CA1146324A - Method and apparatus for the continuous formation of biaxially oriented thermoplastic materials and forming articles therefrom by intermittent forming means interfaced therewith - Google Patents
Method and apparatus for the continuous formation of biaxially oriented thermoplastic materials and forming articles therefrom by intermittent forming means interfaced therewithInfo
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- CA1146324A CA1146324A CA000378800A CA378800A CA1146324A CA 1146324 A CA1146324 A CA 1146324A CA 000378800 A CA000378800 A CA 000378800A CA 378800 A CA378800 A CA 378800A CA 1146324 A CA1146324 A CA 1146324A
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Abstract
ABSTRACT OF THE DISCLOSURE
A method is provided for continuously extruding, biaxially orienting and intermittently forming molded products from a web of thermoplastic material and further, continuously separating the products from the web selvage, stacking and handling the products and recycling the web selvage for further extrusion. The method uses intermittent molding and biaxial orientation devices into which configuration the continuously extruded web is interfaced by continuous-to-intermittent inter-facing loop arrangement which preserves the dimensional and orientational integrity of the web and maintains sufficient thermal stability therein. This provides molded products which are free from defects such as stretch marks and other inertial and thermal discontinuities normally anticipated in cases of intermittent web advance of thermoplastic material at thermo-formable temperature levels.
A method is provided for continuously extruding, biaxially orienting and intermittently forming molded products from a web of thermoplastic material and further, continuously separating the products from the web selvage, stacking and handling the products and recycling the web selvage for further extrusion. The method uses intermittent molding and biaxial orientation devices into which configuration the continuously extruded web is interfaced by continuous-to-intermittent inter-facing loop arrangement which preserves the dimensional and orientational integrity of the web and maintains sufficient thermal stability therein. This provides molded products which are free from defects such as stretch marks and other inertial and thermal discontinuities normally anticipated in cases of intermittent web advance of thermoplastic material at thermo-formable temperature levels.
Description
~146~2~;
This invention relates to methods for biaxially orient-ing thermoplastic materials, e.g., polystyrene and more particu-larly, to a continuous method and manufacturing means for extruding webs of such material and form~ng objects therefrom by interfacing the continuous extrusion process with intermittent orientation and forming means.
The specifics of the following discussion and specifica-tion refer to oriented polystyrene material, hereinafter referred to as OPS but it should be expressly ~nderstood that the process constituting aspects of the present invention is applicable to a wide variety of thermoplastic materials, polymers or mixtures of polymers including such materials as e.g., polymers of ethylene, polypropylene, styrene~ vinyl chloride, etc.
Whilc in~lividual materials have problems whic]) are oftcn eeuliar to tllose materials an~ aml~er commercial cxl)loitatioll of tllem, tllc l)olystyrelle materials exllibit low-cost, lli~]l stiffllcss all~l c~;cellellt transl-arellcy wllell prol~erly orient~l all(l tllc l)rol)er molecular orientati.on urther enhanccs tllc l)olystyrellc material by removin~ its inllerellt brittleness in the abscnce o~ molecul.lr oricntatioll.
l llcrc al'C various l)rior art a~ roacllcs to n~iti~atill~ tllc brittlclless factor in l)olystyrcne materials, by tl~e usc Or iml)~ct molliricrs and tlle like. Ilowever, tllis ~leereases the sti~flless, clilllill;ltcs transl)alerlcy an(l increases tllc cost si~nific;l3ltly.
Illerefore, I rior art al-proaclles to reme~ly the l)rittleness roblem all(l increase the ilnl)act rcsistance of l)olystyrelle result in ccrtnill un~lesiral)le l)rol)erties wllich di~l not cxist pJ-ior to the n~lditioll of sucll modificrs.
~' ~ .
463~2~
I Accor~ ly, i~ sucl~ m;lteli;lIs coul~l he use~ rel;ltively u~ o~irie~ st.~te ill m~l~uL3eturill~ sl)eets or stril)s or this In~terial in a continuous extru~ing process ill wllie~ xial orielltatioll is ¦iml)arted to this material and tllcn, without (Icstloyill~ tllc basic ¦¦continuitY of the proce~s, mol~ articles or otllerwise form ~rticles ¦from it, all of tlle ~esirable pllysical prol)erties of tlle material eoul~ be realized. At the same ti~ne all of tlle ~esira~ilities, sl)ee~ all~ efficiellcies of a su~stanti~lly colltinuous extrusion an~
forlnin~ proeess coul~ be realize~ in tlle ultimate plO~UCt cost.
i11is inte~rated al)~roaell whiell combines contilluous extrusion, ~n~ se4uelltially orientatillg an~ formillg irl rapi~ suecession is the crux of tl-e present inventioll.
lleretoCore, tlle eonventioll.ll al)l)roaches e.g.~ witll foam slleet materials an~ non-~oame~ or noll-cellulllr sheet In~terials has been to first produee sheetillg, store it in roIle~ form an~ terlllina t-the illitial process at that pOillt, 'I'llen, subse~ucntly, the sl-eeting is ul-rollc~l, relleate-l aJld ultimately forme~l illto pro~lucts or ,articles ill its rel~e~te~ state. As with ail tllerlllol)l;lstic teclll~ ues, Ijtllere ale tllree basic il~terrelate(l V;ll'i.ll)lCs illVOlvC~I ill l)I'OCCssill~
This invention relates to methods for biaxially orient-ing thermoplastic materials, e.g., polystyrene and more particu-larly, to a continuous method and manufacturing means for extruding webs of such material and form~ng objects therefrom by interfacing the continuous extrusion process with intermittent orientation and forming means.
The specifics of the following discussion and specifica-tion refer to oriented polystyrene material, hereinafter referred to as OPS but it should be expressly ~nderstood that the process constituting aspects of the present invention is applicable to a wide variety of thermoplastic materials, polymers or mixtures of polymers including such materials as e.g., polymers of ethylene, polypropylene, styrene~ vinyl chloride, etc.
Whilc in~lividual materials have problems whic]) are oftcn eeuliar to tllose materials an~ aml~er commercial cxl)loitatioll of tllem, tllc l)olystyrelle materials exllibit low-cost, lli~]l stiffllcss all~l c~;cellellt transl-arellcy wllell prol~erly orient~l all(l tllc l)rol)er molecular orientati.on urther enhanccs tllc l)olystyrellc material by removin~ its inllerellt brittleness in the abscnce o~ molecul.lr oricntatioll.
l llcrc al'C various l)rior art a~ roacllcs to n~iti~atill~ tllc brittlclless factor in l)olystyrcne materials, by tl~e usc Or iml)~ct molliricrs and tlle like. Ilowever, tllis ~leereases the sti~flless, clilllill;ltcs transl)alerlcy an(l increases tllc cost si~nific;l3ltly.
Illerefore, I rior art al-proaclles to reme~ly the l)rittleness roblem all(l increase the ilnl)act rcsistance of l)olystyrelle result in ccrtnill un~lesiral)le l)rol)erties wllich di~l not cxist pJ-ior to the n~lditioll of sucll modificrs.
~' ~ .
463~2~
I Accor~ ly, i~ sucl~ m;lteli;lIs coul~l he use~ rel;ltively u~ o~irie~ st.~te ill m~l~uL3eturill~ sl)eets or stril)s or this In~terial in a continuous extru~ing process ill wllie~ xial orielltatioll is ¦iml)arted to this material and tllcn, without (Icstloyill~ tllc basic ¦¦continuitY of the proce~s, mol~ articles or otllerwise form ~rticles ¦from it, all of tlle ~esirable pllysical prol)erties of tlle material eoul~ be realized. At the same ti~ne all of tlle ~esira~ilities, sl)ee~ all~ efficiellcies of a su~stanti~lly colltinuous extrusion an~
forlnin~ proeess coul~ be realize~ in tlle ultimate plO~UCt cost.
i11is inte~rated al)~roaell whiell combines contilluous extrusion, ~n~ se4uelltially orientatillg an~ formillg irl rapi~ suecession is the crux of tl-e present inventioll.
lleretoCore, tlle eonventioll.ll al)l)roaches e.g.~ witll foam slleet materials an~ non-~oame~ or noll-cellulllr sheet In~terials has been to first produee sheetillg, store it in roIle~ form an~ terlllina t-the illitial process at that pOillt, 'I'llen, subse~ucntly, the sl-eeting is ul-rollc~l, relleate-l aJld ultimately forme~l illto pro~lucts or ,articles ill its rel~e~te~ state. As with ail tllerlllol)l;lstic teclll~ ues, Ijtllere ale tllree basic il~terrelate(l V;ll'i.ll)lCs illVOlvC~I ill l)I'OCCssill~
2~ tl~e~ ol)l;lsti~ Ill.lteli;lIs wllicl~ eet l)otll tlle ll;-tl~l~ or ~lle ol-el~-¦Itioll al~-l tlle cllalacteristics o~ tlle rillaI l~ro~l~lct. Il~ese v.lrial)les ¦¦;lrc teml-cratllre, tlmc all~l pllysic.ll st.ltc, witl~ tllc l;lttcr vari.ll)le I~lc;ll i1lL~ w itl~ ~)r css UIC, strc s s, ct c .
!~ As a ~e~leral rule, teml)er.lture ,al~l tilllC shou.l~ l)c Illil~illliZ
Iv.Iri;ll)les lec;luse extel~le~ l~eat l~istory cal~ materi;lIIy arfect tl~e l!l)ropcrticsoC;IIlcll~ll)ro~luct Illthcctlscof()l~S rOrcx.lllll)le ¦¦tl~e tellll)elatllle ~It wllicll the materi,ll IllUst l)c oriclltc~ rel)rcscllts ¦~ coml)rolllise l-etweel) Ievels whicll are best rrom ;l flow l~oi~t oC
liview ~ l IeveIs whicll ale l)est ~rom a stress (oriel~tatiol~) pOillt
!~ As a ~e~leral rule, teml)er.lture ,al~l tilllC shou.l~ l)c Illil~illliZ
Iv.Iri;ll)les lec;luse extel~le~ l~eat l~istory cal~ materi;lIIy arfect tl~e l!l)ropcrticsoC;IIlcll~ll)ro~luct Illthcctlscof()l~S rOrcx.lllll)le ¦¦tl~e tellll)elatllle ~It wllicll the materi,ll IllUst l)c oriclltc~ rel)rcscllts ¦~ coml)rolllise l-etweel) Ievels whicll are best rrom ;l flow l~oi~t oC
liview ~ l IeveIs whicll ale l)est ~rom a stress (oriel~tatiol~) pOillt
3() llview. ()I~CC a stl'Css is iml)ose~ at a ~iVCI~ tellll)el.lture, ror ¦Iex;~ lo, ~ oloc~ oliol)t.-tioll is a~llievo~. Ilo~over, tl~e 10ll6or ~1 - 2 -1, . I
11463~4~
tllc illcrclncl~t Or time illvolvc~l l)ct~ccll tl~c ;l~llicvclllcllt; o~ tllat oricntatiol~ an~l ~ sul)se(~uellt operatioll, thc morc strcss (oricllta-tiOII) ~ Igaill be relaxe~. /\ccor~lingly, t]lc (Ic~ree of oricntatio n o~ a l~articular material is not neccssarily a solc runctioll o~ the ¦
S allloullt o~ hc~t stretclling applie~l to that m~teri~l to crcate the oricntation since relaxation o~ that orielltation may silllultancously bc takin~ l-lacc.
Ihcreforc, ~ h~ sl~cccl, intc~rate~l a~ ro;lcll is uni(~ue an~l iml)ort;lnt not ollly from a stall~lpoillt Or cost l~ut also from tlle 10 ¦standl)oillt of results hereto~ore not otherwise attaill~ble.
l Ihese inherent a~lvantages of a high speed integrated al~proac ¦are iml)ortInt in relatively thill l~ro~lucts eg ~ tllose with wall ¦tllicknesscs of 0.005 to 0.010 inclles all~l become illcrcasin~ly si~nifi ¦cant Witll l)ro(lucts h~viJIg wall thicknesses grcater tll~n o.0l0inches 15 ¦lhis is ~lue to tlle fact that conventiollal systen~s as heretofore ~lefille~l, neccssarily involve not only ~re~ter time/teml)erature cxl)osure ~lurin~ the pro~luction of shectill~ from t~l]liC]I tlle ultimate ro~lucts are formcl, but also involve tlle rcllcatin~ all~l sul)se(~ucllt recoolill~ o~ thc sllect ~lurill~ tllc sul)sc(lucllt formill~ ol)cl;ltioll.
2U /~ccor~lill~ly, tlle relicf Or stress occurs ~lurill~ rcllcltin~ ;ll)tl subsc(lucllt rccoolill~ as well as ~lurin~ a l)ossil)lc rcl; xa~ioll ~luri tllc l)ro~lllctioll of the slleetill~ l cr sc.
Theoretically, the ideal process would be biaxially to orient the thermoplastic material, to form it and to cool it simultaneously.
25 In conventional systems, the time factor is significant and there-fore detrimental. Accordingly, the shorter the time factor the less detrimental the effect thereof on the maintenance of a stressed r oriented condition of the _teria1.
114632~! 1 r tlle collve~ltio~ ctl~o~ls elllplo)~e~l fol tl~e l)ro~ ctioll Or articles ma~le from material wllicll is biaxially oriente~l perllal7s tlle most l)opular an~l widely use~ prior art system involves tlle extrusion of a sllcet from a slot die onto a roll tlle teml~erattlre S of that roll being eontrolle~l, an~l thell tllrou~ll a series of a~l~ition ll rolls wllicll first bring the slleet to an al~prol)riate temperature level for orientation an(l then lon~itu~ ally stretch tlle sheet betweell t-10 rolls runllirl~ at (liffercnt spcc~ls. lllis lon~itu~lillal stretehillg or drafting orients tlle matcrial in tlle 10 mael~ine ~lirection. lhe material with tl~e lonFitu~linal orientation is thell passed OlltO a tenter frame to orient it transversely in a manller well-known in the art. Since conventiollal tenterillg involve ;
lar~e lleavy e(~uipmellt, it is also llccessary th;lt teml~eratures be mailltaillc~l in tlle sheetill~ tllrou~ll tlle use Or larL~e exl)ellsive ovenj.
15 IAfter tlle slleeting h lS been oriente(l both lon~itu~ lly an~l trans-¦versely it is then rolled ali(l store(l ~or subse(lucllt use.
¦ 111e formillg oL OI~S sheetillg is usually carrie~l out on noll-¦rotltill~ tllerillorormillg e(luipmellt witll special l)rovisiolls for tlle I()l'S matcri.ll. It is llecossary th;lt tllc relleltill~ of thc slleetill 2(1 ¦.IS i.t is r.~ illtO tlle ~ormin~ e(~uipmcnt l)c m;lillt;lille~l unirorlmly tllrou~llout its wi~ltll afi~l len~tlls. ~s tl~e m;ltcli;ll rca(:lles a satisfactory fornling temperature, tllc stresses llllicll llavc beell iml)ose~l ~lurill~ thc biaxial orienthtioll must bc re.sistc~l by a(le~luate l cl.lml)illg ~levi~:es in or(ler to preclu~le tlle slleet frolll sl~rin};ill~ bac~;
25 to its ori~inal (limensiolls an~l losing the orientation tllereill.
Since m0st non-lotlry formill~ equilllllellt is neccssarily inter-nittcllt ;n its opel;ltion tlle intermittent fec~ lg Or oriellte~l ~ leet ill ~ CI~ collvcntiollal formill~ e~luil)lllcllt illll)o~ics illllcrellt ~(lifficultie; in the creation ancl mailltell;lllce of unirorm teml)erature 3l) con-litiolls tllrou~llout tl~e forming area o~ tlle sl~cet.
i3Z~ I
'I'l~ere;rc sevcral otl~er al-l7ro~cllc.c ~ ll llavc beell use(l to Isome e~tent ill tllc pro~luctioll o~ bi.axially oriente~l sl~cetillg. One joE tl~ese, thc bul)ble T~rocess, is tyl~i.cally t.l~e l~lay mucll tllermo-jl)lastic ~ilm is l)ro~luce~l. By prol)er control ol' tcml)erature an~l 5 Istretc~ g, it is l~ossible to producc a bill~ially oricnte(l film or slleet usinL~ this bubble techllique. Ilowever, in l)ractice it is .I)roven to bc vcry critical because Or teml)erature uniforlllity rc~luirements. Also this techni((ue is not usal)le wherl it comes to Ithickcr Illatericll SUCII as tllat usc(l ill tllermoforme~ alti(:les or 10 products on tlle order of meat trays, containers an(l tableware.
¦ ~urtller, there is some e~luillment in use wllicll simultaneously jstretclles transversely an~l lon~itu(linally. 'I'llis e(~uiplllellt obviates the usc of longitudinal stretchi~ig rolls e.g., tllose l)reviously .~lescribc~17 but it llas certain disaclvalltages, naloely, t]-e amoullt of 5 Iselvage WiliCIl must be (liscar~e(l ~lue to the increase~l scallope~l ff~ect resultill~ from clam~s wllicll are necessarily move(l furtller al)art in tlle longitu(lillal ~li.rection in order to ac]li.cve such a simultalleous biaxial stretclling action.
'I'l~c molccular oricnt;ltioll Or tllcrn~ol~las~i.c n~.ltcri.lls, .IS
Z() ~rcvi.ously i.n~licatecl resui.ts in sigl~iric;lnt .i.ml)rovcmel~ts i.ll m;lll~ of tl~e cll;lracteristics Or ccrtain Or tllesc matcli;lls. 13i.a.~ 1 orienta tion is cssential in most packagillg allcl (lisl~os.lble l)roLIucts. If ,oricl~tatiol~ is only i.n OllC (lirection, cvcn thouyll l)rol)erties may bc Isul)stallti;llly iml)rovecl in that ~lirection, tlley arc re~luce~l ill the 25 lotller ~li.mellsiolls. l'yl)ical of l)ro~lucts wllicll are orielltc(l in one lirectiol~ only are monofilamellts an(l fil)crs. I)uril~g orielltation, tllc molecules in thc matcrial arc slliftecl froln ran~olll coil entall~le mcnt to a relative aliglllllellt l~arallel to l)rillc.il~al axcs o~ stretcll.
'l'llis rcsults ill sigllificallt im~rovcmellts .in l)l~ysical l~rol)crtics, 30 ol~tical l)rol)crtics all~ iml~rove~l barr.ier l~rol~ertics all(l stress Icrack resi St.ll)CC .
1 ~146324t I:ol c~ J)~ loll~ tl~ si~;lL l~lol-~rty illll-lovc~ ts, tll~
iml-~ct strcn~tll in nlaterials e.g., 01'~ .Irc iml~rovc~l on tllc or~er of tcn timcs Witll two to three timcs the tcnsile strcngtJI of noll-oricnte~ polystyrel-e an~ as mucl~ as thrcc times t]lC ilnl)rovelllent in S yiel~ elongation.
lllcre is a definite neccl in tlle art to combiJIe thc a~vantages of continuous cxtrusion with intermittent oricntill~ all~ forming systcms ~ue to the wi~e availability of such intern)ittcllt systems ;IIId tlle cal)ital invcstments whicll tlley rcl)rcscnt. I:urtllcrmore, suc intermittent systems are familiar and basically relia~le e(luipment which have a market acceptancc and goocl will that kcep them in ~cman~.
Accor~ingly, the nee~ is establislle(l to interfacc tllc conti~uous extru~ing systcms ~or thermol)lastics e-g- 7 0l)~ with intermittcnt orienters an~ formers ~llile mcticulously ~reserving the intc~rity of dimension and orientation of tlle continuously ro~uce~ thermol)lastic material. -Ille thcrlllal sta~i1ity of tllc orientc~ tllcrmo~ stic m.ltcriali~ illso critical i~ tllc llcat o~ cxtrusion ~n~ oricnt.~tioll is to bc 2U I)rcscrvc~l in tl~e contilluou~ly l~ro~l~lcc~l wcl) Or tllcrmol~ tic to a su~licicllt ~cglee to l)ermit illtcrmittcnt rOll~ n~ cooling in thc . illtcrmittcnt forming ap~)aratus.
It is therefore an object of one aspect of the present invention to provide a method for forming thermoplastic products by continuous extrusion and intermittent orientation and forming in rapid succession in an integrated in~line system.
An object of yet another aspect of the present invention is to provide a thermoplastic product forming method which extrudes~
biaxially orients and forms thermoplastic products and minimizes, 3(l to an optimum degree 7 the time lag between the extrusion, orien-tation and forming stages thereof.
114~
An object of yet another aspect of the present invention is to provide an integrated method for forming biaxially oriented thermoplastic products in a continuous extrusion, orientation and forming process which achieves higher basic linear speeds than has heretofore been accomplished while interfacing intermitten orienta-tion and forming means with continuous extrusion means to preserve the dimensional, orientational and thermal state of the material through the interface.
An object of yet another object of the present invention is to provide a method for thermoforming biaxially oriented thermo-plastic products of enhanced quality.
By one aspect of this invention, a method is provided for forming products of biaxially oriented thermoplastic material comprising: continuously extruding and providing a web of thermo-plastic material; intermittently ingesting the continuously pro-vided web into intermittently activated biaxial orientation means and biaxially orienting a predetermined throw of the web for each intermittent actuation of the biaxial orientation means; inter-facing the continuously provided web with the the intermittent means ~ 4accumulatingo said continuously provided web in an open loop; the open loop oonfiguration and the throw of the web being compatibly dimensioned such that each throw of web ingested nto the intermittently actuated orientation means will transform the said web from the open loop configuration to a taught substan-tially straight line configuration substantially devoid of stret-ching forces; the compatible dimensions of the throw of the web and the open loop configuration constraining any physical and thermal discontinuities in the web to positions substantially immediately proximate to the extreme ends of each said loop and 1~6~2~
each said throw; and intermittently and immediately ingesting each throw of the biaxially oriented web from the biaxial orienting means into an intermittently actuated thermoformer means synchro-nized therewith and forming products in that portion of the biaxi-ally oriented throw of the web intermediate the discontinuities.
By a variant thereof, the method further includes: separating the formed products from the webj and recycling the remainder of the web for further extrusion.
By a variation thereof, the remainder of the web is first granulated during the recycling.
By another variant, the method further includes: separating and accumulating the formed products from the web; granulating remainder of the web; and recycling the graunlated remainder of the web for further extrusion.
By another aspect of this invention, a method is provided for extruding and orienting a web of thermoplastic material in a continuous mode and subsequently forming molded products therefrom in an intermittent mode without interruption of the continuous mode, comprising: extruding a web of thermoplastic material and presenting it continuously to an orientation means at an optimum orientation temperature; intermittently stretch orienting the web in a biaxial orienting means to a desired degree in the trans-verse and longitudinal dimensions thereof while the web is in a continuous longitudinal motion over predtermined intermittent throw lengths thereof; intermittently extracting the oriented predetermined throw lengths of the oriented web from the biaxial orienting means in synchronism with the intermittent actuations of the latter and ingesting the said throw lengths into a forming means; and intermittently forming products in the throw length6 ~1 46324 of oriented web with the forming means while preserving the in-tegrity of orientation therein.
By a variant thereof, the method includes the further step of: stripping the formed products and the remainder of the web from the forming means.
By a variation thereof, the method includes the further steps of: separating the formed products from the web; and recycling the remainder of the web for further extrusion.
By a further variation, the method further includes stacking the formed products separated from remainder of the web.
By another variant, the method includes the further steps of: separating the formed products from the web; and recycling the remainder of the web for further extrusion.
By a variation of any of these aspects of variants, the thermoplastic material is polystyrene.
By another variation of any of these aspects or variants, in the biaxial orientation means, 50% of the orientation of the predetermined throw lengths of the web in the longitudinal direc-tion is performed both upstream and downstream of the transverse orientation thereof.
By anothen aspect of this invention, a method is provided for forming products of biaxially or'ented thermoplastic material comrpising: continuously extruding a web of thermoplastic material;
biaxially stretching the web in an intermittently actuated biaxial orientation means in a continuous manner,over a predetermined throw length of each actuation of the orientation means to effect biaxial orientation therein and dimension the web for subsequent forming; interfacing the continuously extruded web with the inter-mittently actuated orientation means in a dimensionally and g ~14~3~
thermally stable manner through a graivty formed accumulation loop sized in accordance with the predetermined throw length;
substantially immediately and in synchronism with the orientation means transferring a said throw length of oriented web from the orientation means onto ~ downstream transfer means while maintain-ing the dimensional integrity of the web; and forming products in the intermittently advanced lengths of the web on the transfer means substantially immediately upon the completion of each ad-vance to enhance thermal stability therein and preserve the orientation.
By a variant thereof 5 the method further includes: separating formed products from the remainder of the web; and recycling the remainder of the web for extrusion back into a said web.
By a variation thereof, the remainder of the web is first granulated during the recycling.
By yet another variant, the method further includes: separating and accumulating the formed products from the remainder of the web; granulating the remainder of the web; and recycling the granulated remainder of the web for extrusion.
By a further aspect of this invention, a method is provided for extruding a web of thermoplastic material in a continuous mode and subsequently orienting and forming molded products there-from in an intermittent mode without interruption of the conti-nuous mode, comprising: extruding a web of thermoplastic material and presenting it continuously to an intermittently actuated orientation means at an optimum orientation temperature through a gravity formed accumulator loop accommodating a predetermined throw length of web; stretch orienting the predetermined throw length of web to a desired degree in the transverse and longitu-~1463;24 dinal dimensions thereof while the web is in continuous longitu-dinal motion over a given intermittent actuation cycle of the orientation means; continuously interfacing and juxtaposing the oriented throw of web during the given actuation cycle with a downstream transfer means sunchronized with the orientation means in a dimensionally and thermally stable engagement therewith to preserve the integrity of the orientation and the temperature therein and to establish an intermittent feed mode of the web downstream of the orientation means without disturbing the conti-nuous mode upstream thereof; the downstream transfer means being the input of an intermittent thermoforming means; and intermit-tently forming products in the incremental lengths of oriented web within the thermoforming means substantially immediately upon receipt thereof to enhance the thermal stability of the web while preserving the integrity of orientation therein.
By a variant thereof, the method includes the further steps of: cooling the formed products and the web in the intermittent forming means; stripping the formed products and the remainder of the web from the forming means.
By a variation thereof, the method includes the further steps of; separating the formed products from remainder of the web;
and recycling remainder of the web for further extrusion.
By another variation, the method further includes stacking the formed products separated from remainder of the web.
By yet another variant, the method includes the further steps of: cooling the formed products and the web in the inter-mittent forming means; separating the formed products from the remainder of the web; and recycling remainder of the web for-further extrusion.
~1 463;2~
\
By another aspect of this invention, manufacturing means are provide~ for extruding and presenting a continuous web of thermo-plastic material in a continuous mode and transferring incremental lengths thereof to an orienting and forming device and forming ~roducts in the latter in an intermittent mode downstream of and with no effect on the continuous mode, comprising: first means continuously extruding and presenting a web of thermoplastic material at a temperature suitable for subsequent orientation to an accumulation position; interface means continuously ingesting the extruded web from the extruding and presenting means and intermittently discharging predetermined throw lengths of the web; orientation means intermittently receiving the pPedetermined throw lengths of the web and continuously biaxially orienting the web over each said throw length; each said throw length correspon-ding to a given actuation cycle of the intermittent orientation means; and thermoformer means downstream of the orientation means and synchronized therewith to ingest each throw length of biaxially oriented web and form products therein.
The method of an aspect of the present invention commences with the continuous extrusion of a relatively narrow web of thermoplastic material from a die at a relatively high linear speed and.wXich is cxtru<lc~ at thc l)rercrre~l oricntatioll tcml)cr.lturc. ~t tllC cxtrusioo tcml)cr~turc is ~bove tlle desire~ oricntat.~on tcnll)cr.lturc tllc~l it m;ly be l)assc~l over cooling rolls in or(lcr to brillg it ~owl~ to tllc ~csirc~l orietlt.ltioll tcml-erature. lllc web lcavcs tllc coolill~ rolls cntcrs .an acculllulatillg zone whcrc it .is pcrlllittc~ to S.lg ull~cr tlle I
torcc ot ~ravity in thc l~rovision oL a fa~c or ol)cll lool ~imcllsiolle~l to intcrf.lco thc cyclic throw of tllc intcrmittcnt orielltcr an~
rorn~cr with tlle contilluo-ls~tlow from tlle e.~tru~r. Illc web is ~1 463;~
thcn l)assc(l tIlrou~Il dif$crclltial sI)cc~l rol1s ir dcsir(!d, to i)nl)art a l)rc-lctcrmillccl maximum or l)arti~l amount o~ longitu~ a.l or n~acI~ine <lircctiol~ strctcI~ orlentatioll thcrcto and imme-liately suI~sc~Illent to tI~is ol ientatioll is passe~l illtO a trallsvcr!;c stretcII.illg station whicll consists basically of a pair of divcrgelltly disl)ose(l rotating saw bladc-like dcvices whic11 cngago tl~c web aloIlg cach cdge an-l -~livide it into a series of increments wllicll are tllcn coIltinuously sel)arated transversely to a distance of al)l)roximately three times the original dimension of tIlc extru~lc~l web.
Sillce the longitudinal direction is also ~lesirably oriented by strctchillg on an ordcr of magllitudc of tIlree times t]lC ori~inal diIneJlsioll iE this Ilas not bccn acllievcd by tIIc strctclIing rolls ul stream from thc transverse stretchillg mecIlanism, tlle balance of the longitudinal stretching may be taken care of downstream from the transverse stretching al)paratus. /~11 of tIIe foregoing strctchillg steps, Ilowever are ~)erformed on a continuous and unintcrrulltecl basis by the orientation apparatus OVel tlle extcnt of tllc cycle throw of the intermittently actuatcd oricntcr and former.
After tlle ~ ror)er degree of orientation has bccn biaxially iml)artc(l to t]IC extrude~l and now lcngthcIled aIl~l WidCllCd web of m;ltcri.al, tlle material is imInedi;ltcly trallsfcrrcd tIIrougIl aIl inter-mittcIlt rccd nIealls timcd coterm:iIl;ltely witll tllc actIl;ltioll o~ thc oriclItillL~ a~ ratus aIld syncIlrollizcd witII tIlc intclIlli.ttcnt rormcr to in~est; a givel1 increlIlental lcngtIl of oricntcd wcb Col r csl)oll(lin to a saicl cyclic throw of web and ~lisl)ose it witllill the intcr-llli ttCllt [Ol'IIICI' for an in~mediately succccdi.Ilg t]~C~ o rO,,,,i,-g cyclc.
IIlus I)ccausc of coter1Ilill.ltc an(l si.mlllt.lIlcous actuatioIl Or tlle OriCl~t-ltiOII al)l)ar.ltUs alld tl~c intCrlllittCllt fcc~l IIIC~IIIS, cffcctive mcalls arc l)rovidc~l to mailltain the cliIllcllsiollal aIld oricllt;ltioIlal ~1 ~63;~
illtC~t ity a~ )res~lYo the teml)el.lt--re ill tl~e weh fr-)tll tl~c outlet of tl~c oriclltatlo~ evicc illto tl~e illtcrm:ittollt rorlllor sucll t~ t sufriciellt lleat oE extrusioll an~l oriclltatioll is l)rcsellt to J)ermit tlle rllloforlllin~ .
Illerti~]. all~l tllermal (liscontilluitie~;, ir ;IIIy, tY.i.ll exist only at the ul~strealll and ~lownstrealll extrcmities oE tlle accumulator fake or loop, the ultimate extellt o~ wllicll is controlle~ b~
relative ~cljustlllellt of tlle extrusioll rate all~l cyclie l)erio~l o~ tl-c intermittent orienter an~l formill~ al)l)aratus. lllus, if any such ~liscontinuities exist they are at tllc extremes o E tllo cycl ic throw oE tl~e intcrlllittent former, namely, in tl-e selva~e ratller tl-an in thc fillishell l)ro(lucts.
In the accompanying drawings, Figure 1 is a schematic of an in-line continuous extru-sion, and intermittent biaxial orientation and forming system of one aspect of the present invention;
Figure 2 is a top plan schematic of the system and Figure l;
Figure 3 is a schematic of the cutting, stacking and selvage recycling mechanism used in an aspect of the present in-vention; and Figure 4 is a schematic illustrating the common drive and timing used in an aspect of the present invention.
I~CrCrrillg iJ~ ~Ietail to the ~Irawings ;~ l witll l-;lrtiLul;lr rofcrellce to l:i~ures 1 all~l 2, an extru~ler 11) is ilJustl;ltc(l ;IS
1I,1ViIIg an outl)ut to a ~lie 12 whicll forms ;I llallo~Y wcb 14 ol I)oly-styrcllc or otllcr thcrnlol)lastic cxtru~l;ltc ;ll~(l rc~ls tl~c S;li~CXtrU~I;ltC 14 i.lltO a ballk oE coolillg rolls (~
As illlJstr(lte~l, the extru~ler 1() ~ l tl~c (li~ 12 Eec~
oxtru~;lte web 1~ tO a b;lllk o~ coolill~ rolls (:l~ IYl~ich arc l~rovi(le~3, -- 14 ~
~ 463~
as is well klIowl~ in tlle art, win~lI a sIlit;lbIe IIc;-t e~cllall~e mCtiiUIII
aIld control tllerefor, or wl~ich siml-ly I)rovi~Ie tlIC I)rol)er reaeI~ o~
web m;Iterial 14 ror a ~iVCII temI~erature Or e,xtrIisioll to I)elnlit it to cool sufficiel)tly in tI~e allIbiellt con~Iitiolls of tIIe I)rocess e(Iuil)mel~t sucII tI)at wllen it reaclles aIl inI)Ilt roll a~sell~ it i~
at tlIC I)roI)er teml)er.ltllre ~or orientatioIl.
I1IC illl)ut roller assellIbly l~ is illustr.Ite~ ~is iIlclu~ g a first roller 16A and a second roller 1613 wIIich receives the web 14 in a serI)entine I)atIl therebetweell and whicIl rolls 16A an~ 16L are drivelI at ~ifferential rotational velocities to imI)alt a longi-tu~in.Il or machille ~irection orientatioIl or stretch to the web 14 I)rior to the en~agement o~ the said web 14 with the tCCt]l 18r oE
a transverse ~tretcher blade assembly 18.
Interme~iate the downstream cooling roll ~I~A in tlle cooling roll assembly CI~ and tlle upstream roll 16A Or tlIe inI)Ilt roll assembly 16 is an accumulation area AA ill Wl~iCll the web l~i is permitted to form an accumulation looI) AL as shown in ~ antom es. lIIis acculIlulatioll loop AL is ~orme~ un~er tlle actioll of ~ravity an~ iil resI-onse to the timin~ differelItial c;luse~ by the interfacing Or the continuous emissioIl and cooling Or tIIe web 14 upstrealIl of the accumulatioll area AA an~ tlIe interllIittent orienting aIld ~ormin~ of tllc said web 14 dowIlstrealll of the ~iccumulation area AA.
'I'IIe acculiIul.ltioIl lool) AL becomes taugIIt, witllout stretchi i'-orces l~eing ;I~ ie~l~ as in~lic.lte~l by tllc soli.l ~ e mo~le /~Ls ill I:igure 1. II~e accumIllation lool) AI, I)ul~atcs or altelllatcs betwee tlle sa~gill~ ~otte~ e con~IitioIl an-I the tau~IIt soIi~l linc Illo~le ALS Or tlle web 14 in eoncert witlI tl~e interlllittellt .ICtiOII Or the web ree~ a~I~I transI~ort aI-I)aratus I~ in tlle tl~erlllorormcr ~ oh~n-strealn Or the orielltatioll al)l)aratus as Will be more rully aI)I)arent llcrcinaiStcr.
_ 15 -~1 46;~2~ !
As sIIow~ ures 1 (In~ 2 assembly 2() is ~)rovi~Ie(I ~ow~ tre.
of tIIe traIlsve2se stretcIIer b1a~e asseIllbly 1~3 coInl)risill~ first, secoI~d ;In~l thir-I outl)ut rolls 20A, 2(1I3 aIl~ 2()G exten(Iin~ ~ownstreIlll~in tIIat order, rrom tlle transverse b1a~e asseml)ly 1~3. TIIese ro11erIs 20A, 20I3 and 2t)G may be driveIl at selectively ~irferential rota- I ¦
tioI~al velocities to impart ~urtI~er lon~itlIdilla1 strctcll if ~esired to tlle we~ 14 dowIlstream ol aI~d subse(~ueIlt to tIle in~I)artatioI~ of transverse orientation thereto. Ihe ~ownstreaIn output roller 20C
is en~aged witII tlle surfaces of web a~vaIlce fce~ belts I:B of an intermittent feed device F by I~hicll tlle now oriente~ web matcrial 14 will be carrie~ Into position in the iIltermittent thcrmoforJner TF.
IIle output rollers 20A, 20B and 2UC are mounte~ on a common fran~e 20~ on -~IlicIl the inI~ut rollers 16A and 16~ are also lI~ounte~.
TlIe tr.Insverse stretcll saw bla~es l~ and tIIe nearest rollers thereto naIncly~ the uI)stream input rollers 16A an~ l~B an~ the downstream output rollers 20A, 20B an~ 20C are all ~riven preferably froln a common drive mDtor G~I tllrougII suita~le ~rive belt means an~ the rollers 16B an~ 2()A .Ire illustr.Ited in Iigure 4 as being ~rivell by a common ~rive belt I)C wIIicIl en~a~es drive pulle`ys or sprockets Sl and S2 moullte~ on the sll.lfts of tlle rollers 20A all~ 1613 respeetively.
Iurt.ler tIIe roller 1613 includes a ~rivelI output ueariII~ Gl .IIicIl is Cll~ Cd witII compatiblc ~eariIl~ (or a I)re(Ietcr~ lc~ ratio G2 mouIlte~ on tIlc sIla~t o~ tlle i~litia1 iIl])Ut ro1ler 16A SUCII that tlle ~i~fcrcntia1 spee~ between tlle rolleIs l(-A aIl~ 16~ caIl ~e e~fectu;Ited from tlle same commoII drive me;Ills I)G tIIa~ ~rives botl tllC rol1ers 1613 .Ind 20A.
IIlus tIIe ratio Or tlle ~ears Gl aI1~ G2 C;lll I~C Cll;lll~c~ to var~
tlle amOUllt Or lOn~itUdillal strCt(:ll .lClliCVC(I bCtWCCIl tll(.` initial inI)ut rollers 16A and 1~13.
16;~
Ille last two rolls 2UI3 an~ 2~ on tlle ~lo~nstle;lnl si~e Or tl~e trallsvelse stretc1ler l)lu~les 1~ are also ~Irivell flolll tl)e rirst ~ea~
Gl Or tlle stretcher al)paratus in like mallller by ~C-II'S (;.~, (;4 all~ ¦
G5. Il~e last outl)ut (interface) roll 2~C is ~riven at tl-e surrace sl~ee~l of the ~ee~ belts l:B Or tl~e il~termittellt web a~vance ~ all~ tllis is ~riven in turn by tlle u~strelm sprocket l;l~l. lhese upstrealll sl)rockets ~Rl are ~riven by suital)le ~earill~ ~6 in syn-chrorlisl~ itll tlle intermittent orientatioll mecllallislll 16-18-20.
ln or~er to maintain a constal~t din~ellsiollal relatiollsllip between the transverse stretch saw bla(les 18 an~ tlle initial output roller 20A, the blades 18 are l)ivote~ at t]leir most ~own-stream e~es on tlle respective llivots 1', ratller thall at the centerl of tlle sai~ bla~le.s 18. lherefore, tlle relationsllil) between these ¦
blades 18 an~ tlle output roller 20A renlains constallt ~urin~ adjust mellt of the blacles between a direction l)arallel to the machille ~irectioll oriented at 45 witll resl)ect to the mac}lille ~irection.
Tlle second inl)ut roller 16~ an~ its coml)allioll illl)ut roller 16A in tlle illpUt stretch roll set 16 may be move~ in an(l out to a~just to tlle losition of the transverse stretch saw bla~es 18 ~ellen~in~ )on the a~justed positioll o~ tlle latter. Suitable stol) mealls or l)osses (not sllowll) are l)rovi~le~l on tlle saw bla~le a~ljustlllellt ~;-ckets to illtelact witll tlle mollutill~ ol the various inl)llt rollers 16A all~ 1613 to l-reclll(le ell~a~elllel)t Or tlle rolls wit~
tllo saw bla~e l~ut mailltaillill~ tlle ~Iesire~l imlne~lilte l)roxilllity tllereof.
~ uitable melns (not sllown) are also l)rovi~e~l witllill tlle moLIlltill~l)l;lckot20l)0ftllcoutlutrollst2()tol)lovi~cfor movill~ tll~ tl)ree output rollers 20A, 2~l3 all~l 2()~ al)lrt an~ back to~etller a~;lill to l)rovi~le for tlle tllrea~ of m;ltel-i;ll tllerethrou~l~
;It the be~inllill~ of an extrusioll an~l orielltatioll all~ mol~ cyele !
~1 4~
ell l)laci~lg tlle rollers ul--ler a surriciel)t l)i.~s to l-rovi~le ~
I)re~leter~ e~l IllillilllUIIl Sll.lCillg ;IIUl l)I'CS!;lll-C tll-reoll sllcll as by ~Illal I
air cylill(lers or tlle like, all Or wl~icll is witllin tlle l)ul view Or 01~C oII or-lilla2 y skill in tlle art.
Il~e ell~lless fee~l belts 1:13 of tlle illtermittellt ree~ler 1: are ~lispose~l about input sproekets I~Kl alld outl~ut sl)rocliets F1~2 such th~t 0l7l)0site selvage e~lges of tlle oriellte-l weh 14 will be gripped by tl~e fee~l belts F13. lhus, the wel) 14, witll its ~limellsiorl;ll integrity preserved, will be in~lexe~l tllrough a reci~rocatillg or interJnittellt thermoformer Tl:.
ll~e fee~l belts I-B may be e(~uil)l~e~l t~lith rows Or ul)stan~liJlg teetl~ r:l3r such tllat tllese teeth l~ierce tlle selvage e~lges of the web 14 to l)reserve its ~limerlsional integrity an~l llellce, its orien-tation. Ihe tllermoformer 11; ingests a pre~leterloille~ tllrow lengtl of biaxially oriented web 14 for eacll intermittellt enablelllellt of the web fee~l mecllanism F an(l biaxial orientation mecllanism 1~-18-ZU .
Ille interlnittellt thermoformer 1-1~ is in syllchrollislll witll tllese intermittent fee~l meellanisms tllrouL~h suitable translllissiolls all(l the like SUCII tllat tlle common drive motor Cl)hl (or otller e(luivalent powe~
mealls not sllowll) eontrols the interaction o~ all of tllese mechan~ ¦
isms. lherefore, ~lhen the ~ee~l belts 1:13 are stol~l)e~l the tllermo-~ormer 11~ i11 close its mol~ls 1~1 to l~ro~luce a mol~le~ rocluct 24 ¦
in tlle a~lvallce(l biaYially oriellte~l web 1-1 . I IICII tlle mol~ls 1:~1 willbc OpClIC~] agaill l~rior to tlle COmlllCllCClllCnt of tl~e lle.~t a~lv;ll~ce cycle o tlle wel) 14 from the accumul;ltor lool~ AL l~y tllC illtermi ttCIl jt ~ee~l mecllanislll 1 al~l the associate~l all~l syllcllrollize-l bi;lxi;~l OriCllt;lt.iOII IIIC;IIIS 16-18-2().
llle a~lvallce of tlle weh 14 cle;lrs tlle Lorme~ ro~lucts 24 rrO
the moll~s 11:1~1 all~l carries tllem towar~l tlle CUttillg ;111~1 stacl;illg statioll 23 of l:igure 3.
IJaCII a~lv~llce of the web 14 by tlle ree~l belts 1:13 causcs tlle acculllul;ltor lool~ to shift ~rom tl~e S~ggill~ ]~II;llltOlll line l)ositioll tol tlle soli~l line pOsitiOIl in the m;lllller best illustrate~l in l:i~ure 1.¦
-- 1 8 _ 1l ~1 463~ 1 en, ~uring tlle therllloforl~ g cyc1e of tlle tllermororlller Il: tlle ¦accumulator lool~ ~L resumes tl~e sa~ging ~ alltolll line l)osition lawaitillg tl~e next intermittent advallcc of tlle web 14 througll the jorienter 16-18-20 and web advallce mecllallism l~ 1el1~ ICI1 t]le 5 ! tllerllloformer r~ is opelled to discharge the forlned l-ro~ucts Z4, the !¦next intermittent orientation and fee~ cycle occur ~l~d the accumu-¦¦lator loop AL once more assumes the soli~ line taugllt position of ¦lligure 1.
!~ ln ol~cration, in the biaxial orientation mechanism 1~-18-20 ;the eircular saw bla~es 18 are a~justable about the l)ivot means P
¦between a maximum divergence of 45 to the nlacllille direction or ro~uct center lille and a direction l)arallel to that center line and are driven about their respective central bla~e axes by means ¦~Or ~rive l~ulleys ~P wllich are also positioned for movcment with tlle ~ lades 18 abollt the said resl)ectlve l)ivot means P.
'Ihe teeth 18T about the periphery of eacll bla~e 18 engage tlle ¦~outermost edges of the web 14 and callse it to challge flolll its jillitial extru~e~l dimellsioll at the inl)ut si~le Or the l)la~es to a jn~ucll wi~ler (limellsioll comlllellsurate witl~ the ~ivcrgcll~c at WlliCll the2n ~ a~lc5 arc set at the outl)ut side thereor. In tllis m;lllller, a l,transverse orielitation is iml)arted to tlle wel) 14 ill a colltillnous l~m~llller ,IS it ~ravcrses the transversc oricnt;ltioll l)L;Idcs 18 frolll the inl)llt roll asseml)ly 16 to the outl~tlt rO11 aSSCIIII~IY 2~. 1 ractice, the longitudillal stretchillg or m;lcllille ~irection, 25 llstl ctchillg or orientatioll can l)e carrie(l out imlllc~li;ltcl y l~cl orc or ¦!immediately after the transverse stretclling or half l)efore all~ halfj aftcr tllc sai~l trallsversc stretching. l urtllelmore, ;Illy othcr ratio 0~ illiti.li IlI;lChillC (lireCtiOIl strCtCll alld filla1 lil;lChillC direction Istrctch is also fcasil~le. Thc de~rec of transvcrsc or l.ollgitu~lill;ll¦
11 .
11 .
I' r~ .._ ' ~14632~ !
orientltioll call l~e v~rie~ ~o suit a l);lrticul.ll l)rodllct wllich nlay Ihave de})tll or sllal~e re~luirillg less initial orient~tion of tJIe ¦sheetill~ in one or another dircction. 'Ihercrore, tllc prescllt I inventioll provi~lcs a system wllicll is VCly r.~cilc allcl variable with S ¦ re~ar~ to unique and unusual molded shal-es.
In an aspect of the present invention ? the amount of selvage ¦¦which falls outside of the transverse streteher blades 18 is the ¦ same as that amount of selvage whieh falls outside of the upstand_ ling teeth FBT on the feed belts FB of the intermittent feed meehanism F. -I A wide variety of longitu~inal an~ trallsverse stretch-mo~es can be effectuated with the present invention. In ~11 c~ses, of course tlle transverse stretchill~ is achieveLI wit]~ the zone 1l an~ llot witllin tl~e upstream and ~ownstream zones ~ n~
Iresl)cctively.
¦ l~eferrillg furtller to l~igures 1, ~ and 4, the dialneter of the ! rolls 16A, 16B, 2U~, 20~ all~ 2~C are kept as slllall ~s is collsistent jwitll miniloiZill~ tlle ~leflectioll of tllese rolls ullder lo~d. lhis jlell~s later~l st:iEflless to the web 14 al)d reduces sllrill~bac~ an~
I,atten~nt loss o~ orient;ltion. Also, tl~e distlllce between tlle 20 1 ro.l.ls ill tlle rcsl)cctivc roll sets 1~ alld 2() is l)rcfcr.lblyl~o ~re~ter tll.lll to allow for sli~llt clcarallcc oE tllc wcl) or extrudate ¦
! 14 wl~icll furtller minilllizes tlle sllrin~back wllicll otllerwi.se occurs .ls tllo In-lteri:ll is trallsferred rrom olle roll to Illotller.
¦ Ihe surE;Ice sl~ee~ of tlle second roll 1(~l~ is usu~11y ~ster Ith.lll tlle surr.lce sl)eed of tlle first roll 1~ so ~ to acllieve ~lon~itudill.l1 5trctch ul)stream of the saw b1.ldcs 1~. lf tlle said ¦surf;lcc sl)co~l oE tlle roller 16B is twice th~t oE tlle roller l~A, thell 5~)~ o~ tlle lon~itu~inal or macllille ~irection orient~tio l~occurs in tlle tr~nsrer of m~terial between tl~o tall~ent l)oints of Ithe web 14 oll tl-C rollers 16A all~ 1(13 resl~ectively.
I
~, 1146~1Z~ ~
¦i Also as ShOWII ill l:i~urc 1, tlle teetll 1~'l on ~llC trallsverse ¦Istretcller bla~es 18 are very close to tllc sur~ace o~ tlle second ¦jroller ].6B. 'Ille perimeter speed o~ tlle bl;~-les 18 is pre~erubly l!slightly ~aster but substantially e(~ual to the surL;lce spee~ of Ithe roller 16B thereby making the transfer of material rrom one to !the other more effective. 'rhe teetll 181' actu;llly l)cnetrate the ¦¦edge of the ~eb or striy 14 so as to hol~ the material securely as transverse stretchillg takes place d~lC to the ~ngular orientation l of the blacles 18, t]le latter bein~ best showli witll reference to 1 Figures 2 and 4.
j lhe initial output roller 20A is also positiolle~ very close to tlle teetll 18'1' of the bl~des 18 so as to minimize sllrillkback at tllis l~articular transfer ~oint coml~rise~ by the illterrace bctween '¦ tllc sai~ roll 20A and thc blades 18. 'llle sur~ace sl)eed of tlle roller 20A is usually an~ preferably sli.glltly faster but substan-¦ tially e(~u~l to tlle perimeter sl-eed of the trallsverse stretching bla~es 18, tlle secolld output roller 2()B is IlI;lillt;li.llCd close to tllel !ifirst outl)ut roller 2()A, alld tlle tl~.ird outl-ut ro.ller 2UC close to !
¦jtlle secolld outl)ut roller 20B, ill order to millillliLc sllrillkback 2() ¦1 durill~ the tr.lllsrer ~rom one roller to allotllel. Usu~lly, the secolld outl)ut roller 20B and the third outl)ut roller 2()~ ~re run ¦twice the periplleral speed of tlle first outl)ut roller 20A witll thc rererre~ sl~ee(l being sucll .IS to accollll)lisll tllC l'CllI;lillillg 5()o ofI the longitudillal or m~chille directioll orient;ltioll il~ tlle web 14 ias illustr.lte(l. 'Ille web 14, as it Icavcs tllc third outl)ut ro~ler ¦
ZOC Ol~tO tlle rcel belts ll3 is ~ lly l~ xially ori~llto3.
11 11 ~6324 ¦~ A11 O~ tIIe 1On~itU~ a1 StrCtC~ rO11CI ~; 1(.1\, 1(~13, 2()/~ 3,,~,1 1I 20~ an(l tlle tllir(l output roller 2()C are l)reEcrabl~ coatc(l witll ¦.Eluorocarboll sucll as leflon to avoi~l sticking of tllc wel) 14 thereto.
¦ Also, such rollers arc usually ma~lc ~litll thill-wal1c~l stcc1 tubes in 5 I order to mininlizc tlle lleat retentioll cal~acity an(l lleat trallsfer to the en(ls of the rollers. lllerefore, in tlle arca Or contact with ¦ tl~e wel) 14, the rolls reac]l about tlle salnc tcml)eratllre as that of O the web itself an~l thus maintain thcrlllal stal)ility all(l uniformity 1~ in tlle web 14. Ileat-may also be apl)lic~l to tllc rolls ancl drum by 10 ¦¦ any suitable nleans known in the art.
Refcrellcc is now ma(le to l:igures 1 and 3 in wllich thc molded pro~ucts 24 traveling in the (lirection 26 are delivcre~l to a 1I recil~roc~ting CUttillg an~l stacking n~cans 32 whicll scvcrs tl~c nlO
I I)rO~IUCtS 24 from the selvage of t]lC web 14 an~l causcs tlle sai(l ¦¦ severed l)ro(lucts 24 to be stacl;e~l in a suital31e l~ro~luct stack 24S 1, 1I wllicll is scllematically sllowll. I
While tlle severed pro~lucts travel to a stac}; 2~S, thc selvabc 1.14S travcls to a selvagc gril~ling an~l rccycl.ill~ mc.ll-s ~4 wllicll l~lows Ij tllC L~roullLI sclvaue tllrougll a convc~or tul)c 34A to a rccyclillg 2() !! llol)l)er 34l3 a(ljaccnt a hol)l-cr 36 fe~ rrolll a tul)c 3lA Eroln a source ¦¦ oE llCW l)laStiC grallUlCS 01' I)e11ets to l)lacc both rc~roull~l sclv.lue ¦lan-l tl~e l)cllcts into a mixcr assembly 38 of a tyl)c ~cll-kllowll in 1I tilC lI't to re~ cct botll ~resll raw nl.ltcri;ll all~l rcc)~-:lc-l sclv;l~e 11 illtO thc CXtl u~lcr 10.
In all of tlle cmbo~lilllents of l:igurcs 1, 2 a~l~l 3, tllc various le(luil)mcllt mo-lulcs e.g., tlle cooling roll al)l);lratus, tlle oriellt-linu al)l~;lratus, tllc rormer an~l tlle CUttillg l~ress an~l ~rallulatill&
~al)l)aratus Cor reclai~ the selvagc arc moul~tc(l on a gui~lc tracl;
~il oll a sul)l)orting floor or tllc likc sucll tllat tllesc various Ullits 11 ~
!! I
1 i ~1463Z~
can be placed together in a dimensionally desirable relative orientation to define the final in-line system of the present in-vention. Suitable rollers or wheels W on each of the various components are illustrated schematically as riding along the guide tracks ST.
In any of the foregoing embodiments of aspects of the present invention, an important concept is always positively to restrict shrinkback of the oriented sheet by holding the dimen~ional in-tegrit~ and the thermal stability of the sheet 14 to as close a tolerance as possible.
The thermal integrity of the web 14 subsequent to its orien-tation is also of importance since the temperature of the oriented web 14 in the system of an aspect of the present invention is pre-ferably sufficient for the thermoforming operation to be performed by the downstream theroformer TF. The temperature of the web 14 is controlled, as previously disclosed by the roll or drum struc-ture and/or auxiliary heating means of any suitable type known in the art.
I! Ihe ~imcllsio~ inteF,rity of t:ilc biaxi;lll~ oricntcl anl 2(1 Ijtllerlllally m;l.intaille~l web 14 wl~icl~ cxits r.Om tl~c outl)ut rollcr 20C ¦
!If tl~c intclmittellt orientation mealls 16~ Z~ is m;lintaillc~ by ¦Itl-e tecth l:J~'I on tl~c feed belts lU of the intcrmittcnt [cc~
;mccl-;lll i.sl~ sucl~ tl-at a l)rol)erly oricntc(l all(l st;lb i I izc~l sl~cct Or ¦tl~crlllol)lastic m;lteria.l 14 is incrclllcntc(l within tllc tl~crmQ~orlllcr ll:
¦at a l~rol7cr tcml)craturc for tllcrmoformin~ tl~c l~ro(lucts Z4 thercin.
Illc coolin~ o.[ thc incremclltal scctioll Or ~cb 14 fc-l to tl~e tl~erlno-forlllcr Il: is accol~ lislle~l by tllc thclllloforlllcr Il; wllilc tllc l~ro(luct 24 is in tl)c mol(l an~l thus, whcn tllC wcb 14 bcarill~ tllc l~ro(luct 24 an~ inclu~in~ the sclva~e scral) 14S leavcs tllc thcrlllororlllcr 11:, tllc 3~) Il)ro(lu~t Z~ vc I~OCII fixc(l in tlleir ori~ntc(l .~ fOlnlC(I con(lition~
_ 23 -~1~6.~
Aspects of the present invention combine relatively short cycles (20 to 30 cycles per minute) and correspondingly rapid ex-trusion rates with relatively thick polystyr~ne sheeting on the order of 0.030 inches and up in a preferred operating mode. Ori-entation temperatures on the ~rder of 2600F are considered optimum for retained orientation in OPS material. Slightly higher tem-peratures such as 275F have been found to be less desirable for retention of orientation. The preferred longitudinal orientation mode is 50% elongation upstream of transverse orientation and 50%
downstream thereof in the input and output roller assemblies 16 and 20.
In an alternate embodiment of an aspect of the present inven-tion, referring to Figure 5, the three output rollers 20A, 20B and 20C of the orientation means 16~18-20 of Figures 1, 2 and 4 are replaced by two output rollers 20E and 20~, the upstream output ¦¦rollcr 20l. bcin~ much larger in di~metcr tllall tllc ~ownstrc.lm I¦OUtl)ut rollcr 2~F. 'l'he larger upstrcam outl~ut rollcr 2t)~ is so l,lsizc~ ;Is to ingest substanti.~lly a com~)lcte tl~row Or ;It le.lst ,l)arti.l.lly bricl~tccl wcb 14 corr~sl)olldillu to D c)'ClC of tllc illtCF-~ ittcllt ~ CC~I mc;llls 1. Ille l)ortioll l~ Or tllc oricllt~l w~l) 14 2~ !Icn~ thc slllaller dowllstrc~lll olltl)ut rollcr 2~i: is COllS~l';lillCd to,ll~ss tllrou~ll the therllloformer Tl into a dowllstrc~lll sclvil~c l)ortion ¦I'W~ rcl-ltive to tlle moldcd l)ro~luct 24 sucll tl~t ;Illy l)llySiC~Il or Itllc~lll;ll (li~colltilluiti.cs occ~siollc~l I) y tllC ~ llcl lollcl 2()l:
¦¦not ;Il)l)c.lr in tllc moldc~ l)roduct 24.
~ crcrorc, tlle moldcd l)roduct 24 will bc tllcrlllorollllc~ in th.lt ort.ion o~ tlle wcb 14 on thc fccd beLts ll3 whicll w~lS Lormclly on tllC SLll'l'.lCC O[ tllc l~rgcr outl)ut rollcr 2~l,.
11 - 24 - , ~4632g In this embodiment it should be noted that the feed of the web 14 is inverted on the transverse blades 18 and that a third upstream input roller 16C is required. Also, a third downstream roller 20G is now provided at the downstream end of the feed belts FB adjacent the downstream sprockets FR2 to stabilize the oriented web 14 on the feed means F. Suitable drive gearing interconnects all the rollers 16A, 16B~ 16C, 20E, 20F, 20G, drive sprocket RFl and transverse stretcher blades 18 in a similar manner to that described in connection with Figure4.
Therefore, it can be seen th~t aspects of the present inven-tion provides a means for interacing between a continuous extru-sion mode and an intermittent orienting and forming mode without either mode adversely affecting the integrity of the other or the quality and integrity of the biaxially oriented thermoplastic material in the system.
- 25 _
11463~4~
tllc illcrclncl~t Or time illvolvc~l l)ct~ccll tl~c ;l~llicvclllcllt; o~ tllat oricntatiol~ an~l ~ sul)se(~uellt operatioll, thc morc strcss (oricllta-tiOII) ~ Igaill be relaxe~. /\ccor~lingly, t]lc (Ic~ree of oricntatio n o~ a l~articular material is not neccssarily a solc runctioll o~ the ¦
S allloullt o~ hc~t stretclling applie~l to that m~teri~l to crcate the oricntation since relaxation o~ that orielltation may silllultancously bc takin~ l-lacc.
Ihcreforc, ~ h~ sl~cccl, intc~rate~l a~ ro;lcll is uni(~ue an~l iml)ort;lnt not ollly from a stall~lpoillt Or cost l~ut also from tlle 10 ¦standl)oillt of results hereto~ore not otherwise attaill~ble.
l Ihese inherent a~lvantages of a high speed integrated al~proac ¦are iml)ortInt in relatively thill l~ro~lucts eg ~ tllose with wall ¦tllicknesscs of 0.005 to 0.010 inclles all~l become illcrcasin~ly si~nifi ¦cant Witll l)ro(lucts h~viJIg wall thicknesses grcater tll~n o.0l0inches 15 ¦lhis is ~lue to tlle fact that conventiollal systen~s as heretofore ~lefille~l, neccssarily involve not only ~re~ter time/teml)erature cxl)osure ~lurin~ the pro~luction of shectill~ from t~l]liC]I tlle ultimate ro~lucts are formcl, but also involve tlle rcllcatin~ all~l sul)se(~ucllt recoolill~ o~ thc sllect ~lurill~ tllc sul)sc(lucllt formill~ ol)cl;ltioll.
2U /~ccor~lill~ly, tlle relicf Or stress occurs ~lurill~ rcllcltin~ ;ll)tl subsc(lucllt rccoolill~ as well as ~lurin~ a l)ossil)lc rcl; xa~ioll ~luri tllc l)ro~lllctioll of the slleetill~ l cr sc.
Theoretically, the ideal process would be biaxially to orient the thermoplastic material, to form it and to cool it simultaneously.
25 In conventional systems, the time factor is significant and there-fore detrimental. Accordingly, the shorter the time factor the less detrimental the effect thereof on the maintenance of a stressed r oriented condition of the _teria1.
114632~! 1 r tlle collve~ltio~ ctl~o~ls elllplo)~e~l fol tl~e l)ro~ ctioll Or articles ma~le from material wllicll is biaxially oriente~l perllal7s tlle most l)opular an~l widely use~ prior art system involves tlle extrusion of a sllcet from a slot die onto a roll tlle teml~erattlre S of that roll being eontrolle~l, an~l thell tllrou~ll a series of a~l~ition ll rolls wllicll first bring the slleet to an al~prol)riate temperature level for orientation an(l then lon~itu~ ally stretch tlle sheet betweell t-10 rolls runllirl~ at (liffercnt spcc~ls. lllis lon~itu~lillal stretehillg or drafting orients tlle matcrial in tlle 10 mael~ine ~lirection. lhe material with tl~e lonFitu~linal orientation is thell passed OlltO a tenter frame to orient it transversely in a manller well-known in the art. Since conventiollal tenterillg involve ;
lar~e lleavy e(~uipmellt, it is also llccessary th;lt teml~eratures be mailltaillc~l in tlle sheetill~ tllrou~ll tlle use Or larL~e exl)ellsive ovenj.
15 IAfter tlle slleeting h lS been oriente(l both lon~itu~ lly an~l trans-¦versely it is then rolled ali(l store(l ~or subse(lucllt use.
¦ 111e formillg oL OI~S sheetillg is usually carrie~l out on noll-¦rotltill~ tllerillorormillg e(luipmellt witll special l)rovisiolls for tlle I()l'S matcri.ll. It is llecossary th;lt tllc relleltill~ of thc slleetill 2(1 ¦.IS i.t is r.~ illtO tlle ~ormin~ e(~uipmcnt l)c m;lillt;lille~l unirorlmly tllrou~llout its wi~ltll afi~l len~tlls. ~s tl~e m;ltcli;ll rca(:lles a satisfactory fornling temperature, tllc stresses llllicll llavc beell iml)ose~l ~lurill~ thc biaxial orienthtioll must bc re.sistc~l by a(le~luate l cl.lml)illg ~levi~:es in or(ler to preclu~le tlle slleet frolll sl~rin};ill~ bac~;
25 to its ori~inal (limensiolls an~l losing the orientation tllereill.
Since m0st non-lotlry formill~ equilllllellt is neccssarily inter-nittcllt ;n its opel;ltion tlle intermittent fec~ lg Or oriellte~l ~ leet ill ~ CI~ collvcntiollal formill~ e~luil)lllcllt illll)o~ics illllcrellt ~(lifficultie; in the creation ancl mailltell;lllce of unirorm teml)erature 3l) con-litiolls tllrou~llout tl~e forming area o~ tlle sl~cet.
i3Z~ I
'I'l~ere;rc sevcral otl~er al-l7ro~cllc.c ~ ll llavc beell use(l to Isome e~tent ill tllc pro~luctioll o~ bi.axially oriente~l sl~cetillg. One joE tl~ese, thc bul)ble T~rocess, is tyl~i.cally t.l~e l~lay mucll tllermo-jl)lastic ~ilm is l)ro~luce~l. By prol)er control ol' tcml)erature an~l 5 Istretc~ g, it is l~ossible to producc a bill~ially oricnte(l film or slleet usinL~ this bubble techllique. Ilowever, in l)ractice it is .I)roven to bc vcry critical because Or teml)erature uniforlllity rc~luirements. Also this techni((ue is not usal)le wherl it comes to Ithickcr Illatericll SUCII as tllat usc(l ill tllermoforme~ alti(:les or 10 products on tlle order of meat trays, containers an(l tableware.
¦ ~urtller, there is some e~luillment in use wllicll simultaneously jstretclles transversely an~l lon~itu(linally. 'I'llis e(~uiplllellt obviates the usc of longitudinal stretchi~ig rolls e.g., tllose l)reviously .~lescribc~17 but it llas certain disaclvalltages, naloely, t]-e amoullt of 5 Iselvage WiliCIl must be (liscar~e(l ~lue to the increase~l scallope~l ff~ect resultill~ from clam~s wllicll are necessarily move(l furtller al)art in tlle longitu(lillal ~li.rection in order to ac]li.cve such a simultalleous biaxial stretclling action.
'I'l~c molccular oricnt;ltioll Or tllcrn~ol~las~i.c n~.ltcri.lls, .IS
Z() ~rcvi.ously i.n~licatecl resui.ts in sigl~iric;lnt .i.ml)rovcmel~ts i.ll m;lll~ of tl~e cll;lracteristics Or ccrtain Or tllesc matcli;lls. 13i.a.~ 1 orienta tion is cssential in most packagillg allcl (lisl~os.lble l)roLIucts. If ,oricl~tatiol~ is only i.n OllC (lirection, cvcn thouyll l)rol)erties may bc Isul)stallti;llly iml)rovecl in that ~lirection, tlley arc re~luce~l ill the 25 lotller ~li.mellsiolls. l'yl)ical of l)ro~lucts wllicll are orielltc(l in one lirectiol~ only are monofilamellts an(l fil)crs. I)uril~g orielltation, tllc molecules in thc matcrial arc slliftecl froln ran~olll coil entall~le mcnt to a relative aliglllllellt l~arallel to l)rillc.il~al axcs o~ stretcll.
'l'llis rcsults ill sigllificallt im~rovcmellts .in l)l~ysical l~rol)crtics, 30 ol~tical l)rol)crtics all~ iml~rove~l barr.ier l~rol~ertics all(l stress Icrack resi St.ll)CC .
1 ~146324t I:ol c~ J)~ loll~ tl~ si~;lL l~lol-~rty illll-lovc~ ts, tll~
iml-~ct strcn~tll in nlaterials e.g., 01'~ .Irc iml~rovc~l on tllc or~er of tcn timcs Witll two to three timcs the tcnsile strcngtJI of noll-oricnte~ polystyrel-e an~ as mucl~ as thrcc times t]lC ilnl)rovelllent in S yiel~ elongation.
lllcre is a definite neccl in tlle art to combiJIe thc a~vantages of continuous cxtrusion with intermittent oricntill~ all~ forming systcms ~ue to the wi~e availability of such intern)ittcllt systems ;IIId tlle cal)ital invcstments whicll tlley rcl)rcscnt. I:urtllcrmore, suc intermittent systems are familiar and basically relia~le e(luipment which have a market acceptancc and goocl will that kcep them in ~cman~.
Accor~ingly, the nee~ is establislle(l to interfacc tllc conti~uous extru~ing systcms ~or thermol)lastics e-g- 7 0l)~ with intermittcnt orienters an~ formers ~llile mcticulously ~reserving the intc~rity of dimension and orientation of tlle continuously ro~uce~ thermol)lastic material. -Ille thcrlllal sta~i1ity of tllc orientc~ tllcrmo~ stic m.ltcriali~ illso critical i~ tllc llcat o~ cxtrusion ~n~ oricnt.~tioll is to bc 2U I)rcscrvc~l in tl~e contilluou~ly l~ro~l~lcc~l wcl) Or tllcrmol~ tic to a su~licicllt ~cglee to l)ermit illtcrmittcnt rOll~ n~ cooling in thc . illtcrmittcnt forming ap~)aratus.
It is therefore an object of one aspect of the present invention to provide a method for forming thermoplastic products by continuous extrusion and intermittent orientation and forming in rapid succession in an integrated in~line system.
An object of yet another aspect of the present invention is to provide a thermoplastic product forming method which extrudes~
biaxially orients and forms thermoplastic products and minimizes, 3(l to an optimum degree 7 the time lag between the extrusion, orien-tation and forming stages thereof.
114~
An object of yet another aspect of the present invention is to provide an integrated method for forming biaxially oriented thermoplastic products in a continuous extrusion, orientation and forming process which achieves higher basic linear speeds than has heretofore been accomplished while interfacing intermitten orienta-tion and forming means with continuous extrusion means to preserve the dimensional, orientational and thermal state of the material through the interface.
An object of yet another object of the present invention is to provide a method for thermoforming biaxially oriented thermo-plastic products of enhanced quality.
By one aspect of this invention, a method is provided for forming products of biaxially oriented thermoplastic material comprising: continuously extruding and providing a web of thermo-plastic material; intermittently ingesting the continuously pro-vided web into intermittently activated biaxial orientation means and biaxially orienting a predetermined throw of the web for each intermittent actuation of the biaxial orientation means; inter-facing the continuously provided web with the the intermittent means ~ 4accumulatingo said continuously provided web in an open loop; the open loop oonfiguration and the throw of the web being compatibly dimensioned such that each throw of web ingested nto the intermittently actuated orientation means will transform the said web from the open loop configuration to a taught substan-tially straight line configuration substantially devoid of stret-ching forces; the compatible dimensions of the throw of the web and the open loop configuration constraining any physical and thermal discontinuities in the web to positions substantially immediately proximate to the extreme ends of each said loop and 1~6~2~
each said throw; and intermittently and immediately ingesting each throw of the biaxially oriented web from the biaxial orienting means into an intermittently actuated thermoformer means synchro-nized therewith and forming products in that portion of the biaxi-ally oriented throw of the web intermediate the discontinuities.
By a variant thereof, the method further includes: separating the formed products from the webj and recycling the remainder of the web for further extrusion.
By a variation thereof, the remainder of the web is first granulated during the recycling.
By another variant, the method further includes: separating and accumulating the formed products from the web; granulating remainder of the web; and recycling the graunlated remainder of the web for further extrusion.
By another aspect of this invention, a method is provided for extruding and orienting a web of thermoplastic material in a continuous mode and subsequently forming molded products therefrom in an intermittent mode without interruption of the continuous mode, comprising: extruding a web of thermoplastic material and presenting it continuously to an orientation means at an optimum orientation temperature; intermittently stretch orienting the web in a biaxial orienting means to a desired degree in the trans-verse and longitudinal dimensions thereof while the web is in a continuous longitudinal motion over predtermined intermittent throw lengths thereof; intermittently extracting the oriented predetermined throw lengths of the oriented web from the biaxial orienting means in synchronism with the intermittent actuations of the latter and ingesting the said throw lengths into a forming means; and intermittently forming products in the throw length6 ~1 46324 of oriented web with the forming means while preserving the in-tegrity of orientation therein.
By a variant thereof, the method includes the further step of: stripping the formed products and the remainder of the web from the forming means.
By a variation thereof, the method includes the further steps of: separating the formed products from the web; and recycling the remainder of the web for further extrusion.
By a further variation, the method further includes stacking the formed products separated from remainder of the web.
By another variant, the method includes the further steps of: separating the formed products from the web; and recycling the remainder of the web for further extrusion.
By a variation of any of these aspects of variants, the thermoplastic material is polystyrene.
By another variation of any of these aspects or variants, in the biaxial orientation means, 50% of the orientation of the predetermined throw lengths of the web in the longitudinal direc-tion is performed both upstream and downstream of the transverse orientation thereof.
By anothen aspect of this invention, a method is provided for forming products of biaxially or'ented thermoplastic material comrpising: continuously extruding a web of thermoplastic material;
biaxially stretching the web in an intermittently actuated biaxial orientation means in a continuous manner,over a predetermined throw length of each actuation of the orientation means to effect biaxial orientation therein and dimension the web for subsequent forming; interfacing the continuously extruded web with the inter-mittently actuated orientation means in a dimensionally and g ~14~3~
thermally stable manner through a graivty formed accumulation loop sized in accordance with the predetermined throw length;
substantially immediately and in synchronism with the orientation means transferring a said throw length of oriented web from the orientation means onto ~ downstream transfer means while maintain-ing the dimensional integrity of the web; and forming products in the intermittently advanced lengths of the web on the transfer means substantially immediately upon the completion of each ad-vance to enhance thermal stability therein and preserve the orientation.
By a variant thereof 5 the method further includes: separating formed products from the remainder of the web; and recycling the remainder of the web for extrusion back into a said web.
By a variation thereof, the remainder of the web is first granulated during the recycling.
By yet another variant, the method further includes: separating and accumulating the formed products from the remainder of the web; granulating the remainder of the web; and recycling the granulated remainder of the web for extrusion.
By a further aspect of this invention, a method is provided for extruding a web of thermoplastic material in a continuous mode and subsequently orienting and forming molded products there-from in an intermittent mode without interruption of the conti-nuous mode, comprising: extruding a web of thermoplastic material and presenting it continuously to an intermittently actuated orientation means at an optimum orientation temperature through a gravity formed accumulator loop accommodating a predetermined throw length of web; stretch orienting the predetermined throw length of web to a desired degree in the transverse and longitu-~1463;24 dinal dimensions thereof while the web is in continuous longitu-dinal motion over a given intermittent actuation cycle of the orientation means; continuously interfacing and juxtaposing the oriented throw of web during the given actuation cycle with a downstream transfer means sunchronized with the orientation means in a dimensionally and thermally stable engagement therewith to preserve the integrity of the orientation and the temperature therein and to establish an intermittent feed mode of the web downstream of the orientation means without disturbing the conti-nuous mode upstream thereof; the downstream transfer means being the input of an intermittent thermoforming means; and intermit-tently forming products in the incremental lengths of oriented web within the thermoforming means substantially immediately upon receipt thereof to enhance the thermal stability of the web while preserving the integrity of orientation therein.
By a variant thereof, the method includes the further steps of: cooling the formed products and the web in the intermittent forming means; stripping the formed products and the remainder of the web from the forming means.
By a variation thereof, the method includes the further steps of; separating the formed products from remainder of the web;
and recycling remainder of the web for further extrusion.
By another variation, the method further includes stacking the formed products separated from remainder of the web.
By yet another variant, the method includes the further steps of: cooling the formed products and the web in the inter-mittent forming means; separating the formed products from the remainder of the web; and recycling remainder of the web for-further extrusion.
~1 463;2~
\
By another aspect of this invention, manufacturing means are provide~ for extruding and presenting a continuous web of thermo-plastic material in a continuous mode and transferring incremental lengths thereof to an orienting and forming device and forming ~roducts in the latter in an intermittent mode downstream of and with no effect on the continuous mode, comprising: first means continuously extruding and presenting a web of thermoplastic material at a temperature suitable for subsequent orientation to an accumulation position; interface means continuously ingesting the extruded web from the extruding and presenting means and intermittently discharging predetermined throw lengths of the web; orientation means intermittently receiving the pPedetermined throw lengths of the web and continuously biaxially orienting the web over each said throw length; each said throw length correspon-ding to a given actuation cycle of the intermittent orientation means; and thermoformer means downstream of the orientation means and synchronized therewith to ingest each throw length of biaxially oriented web and form products therein.
The method of an aspect of the present invention commences with the continuous extrusion of a relatively narrow web of thermoplastic material from a die at a relatively high linear speed and.wXich is cxtru<lc~ at thc l)rercrre~l oricntatioll tcml)cr.lturc. ~t tllC cxtrusioo tcml)cr~turc is ~bove tlle desire~ oricntat.~on tcnll)cr.lturc tllc~l it m;ly be l)assc~l over cooling rolls in or(lcr to brillg it ~owl~ to tllc ~csirc~l orietlt.ltioll tcml-erature. lllc web lcavcs tllc coolill~ rolls cntcrs .an acculllulatillg zone whcrc it .is pcrlllittc~ to S.lg ull~cr tlle I
torcc ot ~ravity in thc l~rovision oL a fa~c or ol)cll lool ~imcllsiolle~l to intcrf.lco thc cyclic throw of tllc intcrmittcnt orielltcr an~
rorn~cr with tlle contilluo-ls~tlow from tlle e.~tru~r. Illc web is ~1 463;~
thcn l)assc(l tIlrou~Il dif$crclltial sI)cc~l rol1s ir dcsir(!d, to i)nl)art a l)rc-lctcrmillccl maximum or l)arti~l amount o~ longitu~ a.l or n~acI~ine <lircctiol~ strctcI~ orlentatioll thcrcto and imme-liately suI~sc~Illent to tI~is ol ientatioll is passe~l illtO a trallsvcr!;c stretcII.illg station whicll consists basically of a pair of divcrgelltly disl)ose(l rotating saw bladc-like dcvices whic11 cngago tl~c web aloIlg cach cdge an-l -~livide it into a series of increments wllicll are tllcn coIltinuously sel)arated transversely to a distance of al)l)roximately three times the original dimension of tIlc extru~lc~l web.
Sillce the longitudinal direction is also ~lesirably oriented by strctchillg on an ordcr of magllitudc of tIlree times t]lC ori~inal diIneJlsioll iE this Ilas not bccn acllievcd by tIIc strctclIing rolls ul stream from thc transverse stretchillg mecIlanism, tlle balance of the longitudinal stretching may be taken care of downstream from the transverse stretching al)paratus. /~11 of tIIe foregoing strctchillg steps, Ilowever are ~)erformed on a continuous and unintcrrulltecl basis by the orientation apparatus OVel tlle extcnt of tllc cycle throw of the intermittently actuatcd oricntcr and former.
After tlle ~ ror)er degree of orientation has bccn biaxially iml)artc(l to t]IC extrude~l and now lcngthcIled aIl~l WidCllCd web of m;ltcri.al, tlle material is imInedi;ltcly trallsfcrrcd tIIrougIl aIl inter-mittcIlt rccd nIealls timcd coterm:iIl;ltely witll tllc actIl;ltioll o~ thc oriclItillL~ a~ ratus aIld syncIlrollizcd witII tIlc intclIlli.ttcnt rormcr to in~est; a givel1 increlIlental lcngtIl of oricntcd wcb Col r csl)oll(lin to a saicl cyclic throw of web and ~lisl)ose it witllill the intcr-llli ttCllt [Ol'IIICI' for an in~mediately succccdi.Ilg t]~C~ o rO,,,,i,-g cyclc.
IIlus I)ccausc of coter1Ilill.ltc an(l si.mlllt.lIlcous actuatioIl Or tlle OriCl~t-ltiOII al)l)ar.ltUs alld tl~c intCrlllittCllt fcc~l IIIC~IIIS, cffcctive mcalls arc l)rovidc~l to mailltain the cliIllcllsiollal aIld oricllt;ltioIlal ~1 ~63;~
illtC~t ity a~ )res~lYo the teml)el.lt--re ill tl~e weh fr-)tll tl~c outlet of tl~c oriclltatlo~ evicc illto tl~e illtcrm:ittollt rorlllor sucll t~ t sufriciellt lleat oE extrusioll an~l oriclltatioll is l)rcsellt to J)ermit tlle rllloforlllin~ .
Illerti~]. all~l tllermal (liscontilluitie~;, ir ;IIIy, tY.i.ll exist only at the ul~strealll and ~lownstrealll extrcmities oE tlle accumulator fake or loop, the ultimate extellt o~ wllicll is controlle~ b~
relative ~cljustlllellt of tlle extrusioll rate all~l cyclie l)erio~l o~ tl-c intermittent orienter an~l formill~ al)l)aratus. lllus, if any such ~liscontinuities exist they are at tllc extremes o E tllo cycl ic throw oE tl~e intcrlllittent former, namely, in tl-e selva~e ratller tl-an in thc fillishell l)ro(lucts.
In the accompanying drawings, Figure 1 is a schematic of an in-line continuous extru-sion, and intermittent biaxial orientation and forming system of one aspect of the present invention;
Figure 2 is a top plan schematic of the system and Figure l;
Figure 3 is a schematic of the cutting, stacking and selvage recycling mechanism used in an aspect of the present in-vention; and Figure 4 is a schematic illustrating the common drive and timing used in an aspect of the present invention.
I~CrCrrillg iJ~ ~Ietail to the ~Irawings ;~ l witll l-;lrtiLul;lr rofcrellce to l:i~ures 1 all~l 2, an extru~ler 11) is ilJustl;ltc(l ;IS
1I,1ViIIg an outl)ut to a ~lie 12 whicll forms ;I llallo~Y wcb 14 ol I)oly-styrcllc or otllcr thcrnlol)lastic cxtru~l;ltc ;ll~(l rc~ls tl~c S;li~CXtrU~I;ltC 14 i.lltO a ballk oE coolillg rolls (~
As illlJstr(lte~l, the extru~ler 1() ~ l tl~c (li~ 12 Eec~
oxtru~;lte web 1~ tO a b;lllk o~ coolill~ rolls (:l~ IYl~ich arc l~rovi(le~3, -- 14 ~
~ 463~
as is well klIowl~ in tlle art, win~lI a sIlit;lbIe IIc;-t e~cllall~e mCtiiUIII
aIld control tllerefor, or wl~ich siml-ly I)rovi~Ie tlIC I)rol)er reaeI~ o~
web m;Iterial 14 ror a ~iVCII temI~erature Or e,xtrIisioll to I)elnlit it to cool sufficiel)tly in tI~e allIbiellt con~Iitiolls of tIIe I)rocess e(Iuil)mel~t sucII tI)at wllen it reaclles aIl inI)Ilt roll a~sell~ it i~
at tlIC I)roI)er teml)er.ltllre ~or orientatioIl.
I1IC illl)ut roller assellIbly l~ is illustr.Ite~ ~is iIlclu~ g a first roller 16A and a second roller 1613 wIIich receives the web 14 in a serI)entine I)atIl therebetweell and whicIl rolls 16A an~ 16L are drivelI at ~ifferential rotational velocities to imI)alt a longi-tu~in.Il or machille ~irection orientatioIl or stretch to the web 14 I)rior to the en~agement o~ the said web 14 with the tCCt]l 18r oE
a transverse ~tretcher blade assembly 18.
Interme~iate the downstream cooling roll ~I~A in tlle cooling roll assembly CI~ and tlle upstream roll 16A Or tlIe inI)Ilt roll assembly 16 is an accumulation area AA ill Wl~iCll the web l~i is permitted to form an accumulation looI) AL as shown in ~ antom es. lIIis acculIlulatioll loop AL is ~orme~ un~er tlle actioll of ~ravity an~ iil resI-onse to the timin~ differelItial c;luse~ by the interfacing Or the continuous emissioIl and cooling Or tIIe web 14 upstrealIl of the accumulatioll area AA an~ tlIe interllIittent orienting aIld ~ormin~ of tllc said web 14 dowIlstrealll of the ~iccumulation area AA.
'I'IIe acculiIul.ltioIl lool) AL becomes taugIIt, witllout stretchi i'-orces l~eing ;I~ ie~l~ as in~lic.lte~l by tllc soli.l ~ e mo~le /~Ls ill I:igure 1. II~e accumIllation lool) AI, I)ul~atcs or altelllatcs betwee tlle sa~gill~ ~otte~ e con~IitioIl an-I the tau~IIt soIi~l linc Illo~le ALS Or tlle web 14 in eoncert witlI tl~e interlllittellt .ICtiOII Or the web ree~ a~I~I transI~ort aI-I)aratus I~ in tlle tl~erlllorormcr ~ oh~n-strealn Or the orielltatioll al)l)aratus as Will be more rully aI)I)arent llcrcinaiStcr.
_ 15 -~1 46;~2~ !
As sIIow~ ures 1 (In~ 2 assembly 2() is ~)rovi~Ie(I ~ow~ tre.
of tIIe traIlsve2se stretcIIer b1a~e asseIllbly 1~3 coInl)risill~ first, secoI~d ;In~l thir-I outl)ut rolls 20A, 2(1I3 aIl~ 2()G exten(Iin~ ~ownstreIlll~in tIIat order, rrom tlle transverse b1a~e asseml)ly 1~3. TIIese ro11erIs 20A, 20I3 and 2t)G may be driveIl at selectively ~irferential rota- I ¦
tioI~al velocities to impart ~urtI~er lon~itlIdilla1 strctcll if ~esired to tlle we~ 14 dowIlstream ol aI~d subse(~ueIlt to tIle in~I)artatioI~ of transverse orientation thereto. Ihe ~ownstreaIn output roller 20C
is en~aged witII tlle surfaces of web a~vaIlce fce~ belts I:B of an intermittent feed device F by I~hicll tlle now oriente~ web matcrial 14 will be carrie~ Into position in the iIltermittent thcrmoforJner TF.
IIle output rollers 20A, 20B and 2UC are mounte~ on a common fran~e 20~ on -~IlicIl the inI~ut rollers 16A and 16~ are also lI~ounte~.
TlIe tr.Insverse stretcll saw bla~es l~ and tIIe nearest rollers thereto naIncly~ the uI)stream input rollers 16A an~ l~B an~ the downstream output rollers 20A, 20B an~ 20C are all ~riven preferably froln a common drive mDtor G~I tllrougII suita~le ~rive belt means an~ the rollers 16B an~ 2()A .Ire illustr.Ited in Iigure 4 as being ~rivell by a common ~rive belt I)C wIIicIl en~a~es drive pulle`ys or sprockets Sl and S2 moullte~ on the sll.lfts of tlle rollers 20A all~ 1613 respeetively.
Iurt.ler tIIe roller 1613 includes a ~rivelI output ueariII~ Gl .IIicIl is Cll~ Cd witII compatiblc ~eariIl~ (or a I)re(Ietcr~ lc~ ratio G2 mouIlte~ on tIlc sIla~t o~ tlle i~litia1 iIl])Ut ro1ler 16A SUCII that tlle ~i~fcrcntia1 spee~ between tlle rolleIs l(-A aIl~ 16~ caIl ~e e~fectu;Ited from tlle same commoII drive me;Ills I)G tIIa~ ~rives botl tllC rol1ers 1613 .Ind 20A.
IIlus tIIe ratio Or tlle ~ears Gl aI1~ G2 C;lll I~C Cll;lll~c~ to var~
tlle amOUllt Or lOn~itUdillal strCt(:ll .lClliCVC(I bCtWCCIl tll(.` initial inI)ut rollers 16A and 1~13.
16;~
Ille last two rolls 2UI3 an~ 2~ on tlle ~lo~nstle;lnl si~e Or tl~e trallsvelse stretc1ler l)lu~les 1~ are also ~Irivell flolll tl)e rirst ~ea~
Gl Or tlle stretcher al)paratus in like mallller by ~C-II'S (;.~, (;4 all~ ¦
G5. Il~e last outl)ut (interface) roll 2~C is ~riven at tl-e surrace sl~ee~l of the ~ee~ belts l:B Or tl~e il~termittellt web a~vance ~ all~ tllis is ~riven in turn by tlle u~strelm sprocket l;l~l. lhese upstrealll sl)rockets ~Rl are ~riven by suital)le ~earill~ ~6 in syn-chrorlisl~ itll tlle intermittent orientatioll mecllallislll 16-18-20.
ln or~er to maintain a constal~t din~ellsiollal relatiollsllip between the transverse stretch saw bla(les 18 an~ tlle initial output roller 20A, the blades 18 are l)ivote~ at t]leir most ~own-stream e~es on tlle respective llivots 1', ratller thall at the centerl of tlle sai~ bla~le.s 18. lherefore, tlle relationsllil) between these ¦
blades 18 an~ tlle output roller 20A renlains constallt ~urin~ adjust mellt of the blacles between a direction l)arallel to the machille ~irectioll oriented at 45 witll resl)ect to the mac}lille ~irection.
Tlle second inl)ut roller 16~ an~ its coml)allioll illl)ut roller 16A in tlle illpUt stretch roll set 16 may be move~ in an(l out to a~just to tlle losition of the transverse stretch saw bla~es 18 ~ellen~in~ )on the a~justed positioll o~ tlle latter. Suitable stol) mealls or l)osses (not sllowll) are l)rovi~le~l on tlle saw bla~le a~ljustlllellt ~;-ckets to illtelact witll tlle mollutill~ ol the various inl)llt rollers 16A all~ 1613 to l-reclll(le ell~a~elllel)t Or tlle rolls wit~
tllo saw bla~e l~ut mailltaillill~ tlle ~Iesire~l imlne~lilte l)roxilllity tllereof.
~ uitable melns (not sllown) are also l)rovi~e~l witllill tlle moLIlltill~l)l;lckot20l)0ftllcoutlutrollst2()tol)lovi~cfor movill~ tll~ tl)ree output rollers 20A, 2~l3 all~l 2()~ al)lrt an~ back to~etller a~;lill to l)rovi~le for tlle tllrea~ of m;ltel-i;ll tllerethrou~l~
;It the be~inllill~ of an extrusioll an~l orielltatioll all~ mol~ cyele !
~1 4~
ell l)laci~lg tlle rollers ul--ler a surriciel)t l)i.~s to l-rovi~le ~
I)re~leter~ e~l IllillilllUIIl Sll.lCillg ;IIUl l)I'CS!;lll-C tll-reoll sllcll as by ~Illal I
air cylill(lers or tlle like, all Or wl~icll is witllin tlle l)ul view Or 01~C oII or-lilla2 y skill in tlle art.
Il~e ell~lless fee~l belts 1:13 of tlle illtermittellt ree~ler 1: are ~lispose~l about input sproekets I~Kl alld outl~ut sl)rocliets F1~2 such th~t 0l7l)0site selvage e~lges of tlle oriellte-l weh 14 will be gripped by tl~e fee~l belts F13. lhus, the wel) 14, witll its ~limellsiorl;ll integrity preserved, will be in~lexe~l tllrough a reci~rocatillg or interJnittellt thermoformer Tl:.
ll~e fee~l belts I-B may be e(~uil)l~e~l t~lith rows Or ul)stan~liJlg teetl~ r:l3r such tllat tllese teeth l~ierce tlle selvage e~lges of the web 14 to l)reserve its ~limerlsional integrity an~l llellce, its orien-tation. Ihe tllermoformer 11; ingests a pre~leterloille~ tllrow lengtl of biaxially oriented web 14 for eacll intermittellt enablelllellt of the web fee~l mecllanism F an(l biaxial orientation mecllanism 1~-18-ZU .
Ille interlnittellt thermoformer 1-1~ is in syllchrollislll witll tllese intermittent fee~l meellanisms tllrouL~h suitable translllissiolls all(l the like SUCII tllat tlle common drive motor Cl)hl (or otller e(luivalent powe~
mealls not sllowll) eontrols the interaction o~ all of tllese mechan~ ¦
isms. lherefore, ~lhen the ~ee~l belts 1:13 are stol~l)e~l the tllermo-~ormer 11~ i11 close its mol~ls 1~1 to l~ro~luce a mol~le~ rocluct 24 ¦
in tlle a~lvallce(l biaYially oriellte~l web 1-1 . I IICII tlle mol~ls 1:~1 willbc OpClIC~] agaill l~rior to tlle COmlllCllCClllCnt of tl~e lle.~t a~lv;ll~ce cycle o tlle wel) 14 from the accumul;ltor lool~ AL l~y tllC illtermi ttCIl jt ~ee~l mecllanislll 1 al~l the associate~l all~l syllcllrollize-l bi;lxi;~l OriCllt;lt.iOII IIIC;IIIS 16-18-2().
llle a~lvallce of tlle weh 14 cle;lrs tlle Lorme~ ro~lucts 24 rrO
the moll~s 11:1~1 all~l carries tllem towar~l tlle CUttillg ;111~1 stacl;illg statioll 23 of l:igure 3.
IJaCII a~lv~llce of the web 14 by tlle ree~l belts 1:13 causcs tlle acculllul;ltor lool~ to shift ~rom tl~e S~ggill~ ]~II;llltOlll line l)ositioll tol tlle soli~l line pOsitiOIl in the m;lllller best illustrate~l in l:i~ure 1.¦
-- 1 8 _ 1l ~1 463~ 1 en, ~uring tlle therllloforl~ g cyc1e of tlle tllermororlller Il: tlle ¦accumulator lool~ ~L resumes tl~e sa~ging ~ alltolll line l)osition lawaitillg tl~e next intermittent advallcc of tlle web 14 througll the jorienter 16-18-20 and web advallce mecllallism l~ 1el1~ ICI1 t]le 5 ! tllerllloformer r~ is opelled to discharge the forlned l-ro~ucts Z4, the !¦next intermittent orientation and fee~ cycle occur ~l~d the accumu-¦¦lator loop AL once more assumes the soli~ line taugllt position of ¦lligure 1.
!~ ln ol~cration, in the biaxial orientation mechanism 1~-18-20 ;the eircular saw bla~es 18 are a~justable about the l)ivot means P
¦between a maximum divergence of 45 to the nlacllille direction or ro~uct center lille and a direction l)arallel to that center line and are driven about their respective central bla~e axes by means ¦~Or ~rive l~ulleys ~P wllich are also positioned for movcment with tlle ~ lades 18 abollt the said resl)ectlve l)ivot means P.
'Ihe teeth 18T about the periphery of eacll bla~e 18 engage tlle ¦~outermost edges of the web 14 and callse it to challge flolll its jillitial extru~e~l dimellsioll at the inl)ut si~le Or the l)la~es to a jn~ucll wi~ler (limellsioll comlllellsurate witl~ the ~ivcrgcll~c at WlliCll the2n ~ a~lc5 arc set at the outl)ut side thereor. In tllis m;lllller, a l,transverse orielitation is iml)arted to tlle wel) 14 ill a colltillnous l~m~llller ,IS it ~ravcrses the transversc oricnt;ltioll l)L;Idcs 18 frolll the inl)llt roll asseml)ly 16 to the outl~tlt rO11 aSSCIIII~IY 2~. 1 ractice, the longitudillal stretchillg or m;lcllille ~irection, 25 llstl ctchillg or orientatioll can l)e carrie(l out imlllc~li;ltcl y l~cl orc or ¦!immediately after the transverse stretclling or half l)efore all~ halfj aftcr tllc sai~l trallsversc stretching. l urtllelmore, ;Illy othcr ratio 0~ illiti.li IlI;lChillC (lireCtiOIl strCtCll alld filla1 lil;lChillC direction Istrctch is also fcasil~le. Thc de~rec of transvcrsc or l.ollgitu~lill;ll¦
11 .
11 .
I' r~ .._ ' ~14632~ !
orientltioll call l~e v~rie~ ~o suit a l);lrticul.ll l)rodllct wllich nlay Ihave de})tll or sllal~e re~luirillg less initial orient~tion of tJIe ¦sheetill~ in one or another dircction. 'Ihercrore, tllc prescllt I inventioll provi~lcs a system wllicll is VCly r.~cilc allcl variable with S ¦ re~ar~ to unique and unusual molded shal-es.
In an aspect of the present invention ? the amount of selvage ¦¦which falls outside of the transverse streteher blades 18 is the ¦ same as that amount of selvage whieh falls outside of the upstand_ ling teeth FBT on the feed belts FB of the intermittent feed meehanism F. -I A wide variety of longitu~inal an~ trallsverse stretch-mo~es can be effectuated with the present invention. In ~11 c~ses, of course tlle transverse stretchill~ is achieveLI wit]~ the zone 1l an~ llot witllin tl~e upstream and ~ownstream zones ~ n~
Iresl)cctively.
¦ l~eferrillg furtller to l~igures 1, ~ and 4, the dialneter of the ! rolls 16A, 16B, 2U~, 20~ all~ 2~C are kept as slllall ~s is collsistent jwitll miniloiZill~ tlle ~leflectioll of tllese rolls ullder lo~d. lhis jlell~s later~l st:iEflless to the web 14 al)d reduces sllrill~bac~ an~
I,atten~nt loss o~ orient;ltion. Also, tl~e distlllce between tlle 20 1 ro.l.ls ill tlle rcsl)cctivc roll sets 1~ alld 2() is l)rcfcr.lblyl~o ~re~ter tll.lll to allow for sli~llt clcarallcc oE tllc wcl) or extrudate ¦
! 14 wl~icll furtller minilllizes tlle sllrin~back wllicll otllerwi.se occurs .ls tllo In-lteri:ll is trallsferred rrom olle roll to Illotller.
¦ Ihe surE;Ice sl~ee~ of tlle second roll 1(~l~ is usu~11y ~ster Ith.lll tlle surr.lce sl)eed of tlle first roll 1~ so ~ to acllieve ~lon~itudill.l1 5trctch ul)stream of the saw b1.ldcs 1~. lf tlle said ¦surf;lcc sl)co~l oE tlle roller 16B is twice th~t oE tlle roller l~A, thell 5~)~ o~ tlle lon~itu~inal or macllille ~irection orient~tio l~occurs in tlle tr~nsrer of m~terial between tl~o tall~ent l)oints of Ithe web 14 oll tl-C rollers 16A all~ 1(13 resl~ectively.
I
~, 1146~1Z~ ~
¦i Also as ShOWII ill l:i~urc 1, tlle teetll 1~'l on ~llC trallsverse ¦Istretcller bla~es 18 are very close to tllc sur~ace o~ tlle second ¦jroller ].6B. 'Ille perimeter speed o~ tlle bl;~-les 18 is pre~erubly l!slightly ~aster but substantially e(~ual to the surL;lce spee~ of Ithe roller 16B thereby making the transfer of material rrom one to !the other more effective. 'rhe teetll 181' actu;llly l)cnetrate the ¦¦edge of the ~eb or striy 14 so as to hol~ the material securely as transverse stretchillg takes place d~lC to the ~ngular orientation l of the blacles 18, t]le latter bein~ best showli witll reference to 1 Figures 2 and 4.
j lhe initial output roller 20A is also positiolle~ very close to tlle teetll 18'1' of the bl~des 18 so as to minimize sllrillkback at tllis l~articular transfer ~oint coml~rise~ by the illterrace bctween '¦ tllc sai~ roll 20A and thc blades 18. 'llle sur~ace sl)eed of tlle roller 20A is usually an~ preferably sli.glltly faster but substan-¦ tially e(~u~l to tlle perimeter sl-eed of the trallsverse stretching bla~es 18, tlle secolld output roller 2()B is IlI;lillt;li.llCd close to tllel !ifirst outl)ut roller 2()A, alld tlle tl~.ird outl-ut ro.ller 2UC close to !
¦jtlle secolld outl)ut roller 20B, ill order to millillliLc sllrillkback 2() ¦1 durill~ the tr.lllsrer ~rom one roller to allotllel. Usu~lly, the secolld outl)ut roller 20B and the third outl)ut roller 2()~ ~re run ¦twice the periplleral speed of tlle first outl)ut roller 20A witll thc rererre~ sl~ee(l being sucll .IS to accollll)lisll tllC l'CllI;lillillg 5()o ofI the longitudillal or m~chille directioll orient;ltioll il~ tlle web 14 ias illustr.lte(l. 'Ille web 14, as it Icavcs tllc third outl)ut ro~ler ¦
ZOC Ol~tO tlle rcel belts ll3 is ~ lly l~ xially ori~llto3.
11 11 ~6324 ¦~ A11 O~ tIIe 1On~itU~ a1 StrCtC~ rO11CI ~; 1(.1\, 1(~13, 2()/~ 3,,~,1 1I 20~ an(l tlle tllir(l output roller 2()C are l)reEcrabl~ coatc(l witll ¦.Eluorocarboll sucll as leflon to avoi~l sticking of tllc wel) 14 thereto.
¦ Also, such rollers arc usually ma~lc ~litll thill-wal1c~l stcc1 tubes in 5 I order to mininlizc tlle lleat retentioll cal~acity an(l lleat trallsfer to the en(ls of the rollers. lllerefore, in tlle arca Or contact with ¦ tl~e wel) 14, the rolls reac]l about tlle salnc tcml)eratllre as that of O the web itself an~l thus maintain thcrlllal stal)ility all(l uniformity 1~ in tlle web 14. Ileat-may also be apl)lic~l to tllc rolls ancl drum by 10 ¦¦ any suitable nleans known in the art.
Refcrellcc is now ma(le to l:igures 1 and 3 in wllich thc molded pro~ucts 24 traveling in the (lirection 26 are delivcre~l to a 1I recil~roc~ting CUttillg an~l stacking n~cans 32 whicll scvcrs tl~c nlO
I I)rO~IUCtS 24 from the selvage of t]lC web 14 an~l causcs tlle sai(l ¦¦ severed l)ro(lucts 24 to be stacl;e~l in a suital31e l~ro~luct stack 24S 1, 1I wllicll is scllematically sllowll. I
While tlle severed pro~lucts travel to a stac}; 2~S, thc selvabc 1.14S travcls to a selvagc gril~ling an~l rccycl.ill~ mc.ll-s ~4 wllicll l~lows Ij tllC L~roullLI sclvaue tllrougll a convc~or tul)c 34A to a rccyclillg 2() !! llol)l)er 34l3 a(ljaccnt a hol)l-cr 36 fe~ rrolll a tul)c 3lA Eroln a source ¦¦ oE llCW l)laStiC grallUlCS 01' I)e11ets to l)lacc both rc~roull~l sclv.lue ¦lan-l tl~e l)cllcts into a mixcr assembly 38 of a tyl)c ~cll-kllowll in 1I tilC lI't to re~ cct botll ~resll raw nl.ltcri;ll all~l rcc)~-:lc-l sclv;l~e 11 illtO thc CXtl u~lcr 10.
In all of tlle cmbo~lilllents of l:igurcs 1, 2 a~l~l 3, tllc various le(luil)mcllt mo-lulcs e.g., tlle cooling roll al)l);lratus, tlle oriellt-linu al)l~;lratus, tllc rormer an~l tlle CUttillg l~ress an~l ~rallulatill&
~al)l)aratus Cor reclai~ the selvagc arc moul~tc(l on a gui~lc tracl;
~il oll a sul)l)orting floor or tllc likc sucll tllat tllesc various Ullits 11 ~
!! I
1 i ~1463Z~
can be placed together in a dimensionally desirable relative orientation to define the final in-line system of the present in-vention. Suitable rollers or wheels W on each of the various components are illustrated schematically as riding along the guide tracks ST.
In any of the foregoing embodiments of aspects of the present invention, an important concept is always positively to restrict shrinkback of the oriented sheet by holding the dimen~ional in-tegrit~ and the thermal stability of the sheet 14 to as close a tolerance as possible.
The thermal integrity of the web 14 subsequent to its orien-tation is also of importance since the temperature of the oriented web 14 in the system of an aspect of the present invention is pre-ferably sufficient for the thermoforming operation to be performed by the downstream theroformer TF. The temperature of the web 14 is controlled, as previously disclosed by the roll or drum struc-ture and/or auxiliary heating means of any suitable type known in the art.
I! Ihe ~imcllsio~ inteF,rity of t:ilc biaxi;lll~ oricntcl anl 2(1 Ijtllerlllally m;l.intaille~l web 14 wl~icl~ cxits r.Om tl~c outl)ut rollcr 20C ¦
!If tl~c intclmittellt orientation mealls 16~ Z~ is m;lintaillc~ by ¦Itl-e tecth l:J~'I on tl~c feed belts lU of the intcrmittcnt [cc~
;mccl-;lll i.sl~ sucl~ tl-at a l)rol)erly oricntc(l all(l st;lb i I izc~l sl~cct Or ¦tl~crlllol)lastic m;lteria.l 14 is incrclllcntc(l within tllc tl~crmQ~orlllcr ll:
¦at a l~rol7cr tcml)craturc for tllcrmoformin~ tl~c l~ro(lucts Z4 thercin.
Illc coolin~ o.[ thc incremclltal scctioll Or ~cb 14 fc-l to tl~e tl~erlno-forlllcr Il: is accol~ lislle~l by tllc thclllloforlllcr Il; wllilc tllc l~ro(luct 24 is in tl)c mol(l an~l thus, whcn tllC wcb 14 bcarill~ tllc l~ro(luct 24 an~ inclu~in~ the sclva~e scral) 14S leavcs tllc thcrlllororlllcr 11:, tllc 3~) Il)ro(lu~t Z~ vc I~OCII fixc(l in tlleir ori~ntc(l .~ fOlnlC(I con(lition~
_ 23 -~1~6.~
Aspects of the present invention combine relatively short cycles (20 to 30 cycles per minute) and correspondingly rapid ex-trusion rates with relatively thick polystyr~ne sheeting on the order of 0.030 inches and up in a preferred operating mode. Ori-entation temperatures on the ~rder of 2600F are considered optimum for retained orientation in OPS material. Slightly higher tem-peratures such as 275F have been found to be less desirable for retention of orientation. The preferred longitudinal orientation mode is 50% elongation upstream of transverse orientation and 50%
downstream thereof in the input and output roller assemblies 16 and 20.
In an alternate embodiment of an aspect of the present inven-tion, referring to Figure 5, the three output rollers 20A, 20B and 20C of the orientation means 16~18-20 of Figures 1, 2 and 4 are replaced by two output rollers 20E and 20~, the upstream output ¦¦rollcr 20l. bcin~ much larger in di~metcr tllall tllc ~ownstrc.lm I¦OUtl)ut rollcr 2~F. 'l'he larger upstrcam outl~ut rollcr 2t)~ is so l,lsizc~ ;Is to ingest substanti.~lly a com~)lcte tl~row Or ;It le.lst ,l)arti.l.lly bricl~tccl wcb 14 corr~sl)olldillu to D c)'ClC of tllc illtCF-~ ittcllt ~ CC~I mc;llls 1. Ille l)ortioll l~ Or tllc oricllt~l w~l) 14 2~ !Icn~ thc slllaller dowllstrc~lll olltl)ut rollcr 2~i: is COllS~l';lillCd to,ll~ss tllrou~ll the therllloformer Tl into a dowllstrc~lll sclvil~c l)ortion ¦I'W~ rcl-ltive to tlle moldcd l)ro~luct 24 sucll tl~t ;Illy l)llySiC~Il or Itllc~lll;ll (li~colltilluiti.cs occ~siollc~l I) y tllC ~ llcl lollcl 2()l:
¦¦not ;Il)l)c.lr in tllc moldc~ l)roduct 24.
~ crcrorc, tlle moldcd l)roduct 24 will bc tllcrlllorollllc~ in th.lt ort.ion o~ tlle wcb 14 on thc fccd beLts ll3 whicll w~lS Lormclly on tllC SLll'l'.lCC O[ tllc l~rgcr outl)ut rollcr 2~l,.
11 - 24 - , ~4632g In this embodiment it should be noted that the feed of the web 14 is inverted on the transverse blades 18 and that a third upstream input roller 16C is required. Also, a third downstream roller 20G is now provided at the downstream end of the feed belts FB adjacent the downstream sprockets FR2 to stabilize the oriented web 14 on the feed means F. Suitable drive gearing interconnects all the rollers 16A, 16B~ 16C, 20E, 20F, 20G, drive sprocket RFl and transverse stretcher blades 18 in a similar manner to that described in connection with Figure4.
Therefore, it can be seen th~t aspects of the present inven-tion provides a means for interacing between a continuous extru-sion mode and an intermittent orienting and forming mode without either mode adversely affecting the integrity of the other or the quality and integrity of the biaxially oriented thermoplastic material in the system.
- 25 _
Claims (33)
1. The method of forming products of biaxially oriented thermoplastic material comprising:
continuously extruding and providing a web of thermo-plastic material;
intermittently ingesting said continuously provided web into intermittently activated biaxial orientation means and biaxially orienting a predetermined throw of said web for each in-termittent actuation of said biaxial orientation means;
interfacing said continuously provided web with the said intermittent means by accumulating said continuously provided web in an open loop;
said open loop configuration and said throw of said web being compatibly dimensioned such that each throw of web in-gested into said intermittently actuated orientation means will transform the said web from said open loop configuration to a taught substantially straight line configuration substantially devoid of stretching forces;
the compatible dimensions of said throw of said web and said open loop configuration constraining any physical and thermal discontinuities in said web to positions substantially immediately proximate to the extreme ends of each said loop and each said throw; and intermittently and immediately ingesting each throw of said biaxially oriented web from said biaxial orienting means into an intermittently actuated thermoformer means synchronized therewith and forming products in that portion of the biaxially oriented throw of said web intermediate said discontinuities.
continuously extruding and providing a web of thermo-plastic material;
intermittently ingesting said continuously provided web into intermittently activated biaxial orientation means and biaxially orienting a predetermined throw of said web for each in-termittent actuation of said biaxial orientation means;
interfacing said continuously provided web with the said intermittent means by accumulating said continuously provided web in an open loop;
said open loop configuration and said throw of said web being compatibly dimensioned such that each throw of web in-gested into said intermittently actuated orientation means will transform the said web from said open loop configuration to a taught substantially straight line configuration substantially devoid of stretching forces;
the compatible dimensions of said throw of said web and said open loop configuration constraining any physical and thermal discontinuities in said web to positions substantially immediately proximate to the extreme ends of each said loop and each said throw; and intermittently and immediately ingesting each throw of said biaxially oriented web from said biaxial orienting means into an intermittently actuated thermoformer means synchronized therewith and forming products in that portion of the biaxially oriented throw of said web intermediate said discontinuities.
2. The method of claim 1 which further includes:
separating the formed products from said web; and recycling the remainder of said web for further extrusion.
separating the formed products from said web; and recycling the remainder of said web for further extrusion.
3. The method of claim 2, wherein said remainder of said web is first granulated during said recycling.
4. The method of claim 1, which further includes:
separating and accumulating said formed products from said web;
granulating remainder of said web; and recycling said granulated remainder of said web for further extrusion.
separating and accumulating said formed products from said web;
granulating remainder of said web; and recycling said granulated remainder of said web for further extrusion.
5. The method of extruding and orienting a web of thermoplastic material in a continuous mode and subsequently form-ing molded products therefrom in an intermittent mode without interruption of said continuous mode, comprising:
extruding a web of thermoplastic material and presenting it continuously to an orientation means at an optimum orientation temperature;
intermittently stretch orienting the web in a biaxial orienting means to a desired degree in the transverse and longi-tudinal dimensions thereof while said web is in a continuous lon-gitudinal motion over predetermined intermittent throw lengths thereof;
intermittently extracting the oriented predetermined throw lengths of the oriented web from the biaxial orienting means in synchronism with the intermittent actuations of the latter and ingesting the said throw lengths into a forming means; and intermittently forming products in said throw lengths of oriented web with said forming means while preserving the in-tegrity of orientation therein.
extruding a web of thermoplastic material and presenting it continuously to an orientation means at an optimum orientation temperature;
intermittently stretch orienting the web in a biaxial orienting means to a desired degree in the transverse and longi-tudinal dimensions thereof while said web is in a continuous lon-gitudinal motion over predetermined intermittent throw lengths thereof;
intermittently extracting the oriented predetermined throw lengths of the oriented web from the biaxial orienting means in synchronism with the intermittent actuations of the latter and ingesting the said throw lengths into a forming means; and intermittently forming products in said throw lengths of oriented web with said forming means while preserving the in-tegrity of orientation therein.
6. The method of claim 5, which includes the further step of:
stripping said formed products and the remainder of said web from said forming means.
stripping said formed products and the remainder of said web from said forming means.
7. The method of claim 6, which includes the further steps of:
separating the formed products from the web; and recycling the remainder of said web for further extrusion.
separating the formed products from the web; and recycling the remainder of said web for further extrusion.
8. The method of claim 7, which further includes stack-ing the formed products separated from remainder of said web.
9. The method of claim 5, which includes the further steps of:
separating the formed products from the web; and recycling the remainder of said web for further extrusion.
separating the formed products from the web; and recycling the remainder of said web for further extrusion.
10. The method of claim 9, which further includes stack-ing the formed products separated from remainder of said web.
11. The method of claims 1, 2 or 5, wherein the thermoplastic material is polystyrene.
12. The method of claims 1, 2 or S, wherein in said biaxial orientation means, 50% of the orientation of said prede-termined throw lengths of said web in the longitudinal direction is performed both upstream and downstream of the transverse orien-tation thereof.
13. The method of claims 1, 2 or 5, wherein in said biaxial orientation means, 50% of the orientation of said prede-termined throw lengths of said web in the longitudinal direction is performed both upstream and downstream of the transverse orientation thereof; and wherein said thermoplastic material is polystyrene.
14. The method of forming products of biaxially oriented thermoplastic material comprising:
continuously extruding a web of thermoplastic material;
biaxially stretching said web in an intermittently actuated biaxial orientation means in a continuous manner over a predetermined throw length of each actuation of said orientation means to effect biaxial orientation therein and dimension said web for subsequent forming:
interfacing said continuously extruded web with said intermittently actuated orientation means in a dimensionally and thermally stable manner through a gravity formed accumulation loop sized in accordance with said predetermined throw length;
substantially immediately and in synchronism with said orientation means transferring a said throw length of oriented web from said orientation means onto a downstream transfer means while maintaining the dimensional integrity of said web; and forming products in said intermittently advanced lengths of said web on said transfer means substantially immediately upon the completion of each advance to enhance thermal stability therein and preserve said orientation.
continuously extruding a web of thermoplastic material;
biaxially stretching said web in an intermittently actuated biaxial orientation means in a continuous manner over a predetermined throw length of each actuation of said orientation means to effect biaxial orientation therein and dimension said web for subsequent forming:
interfacing said continuously extruded web with said intermittently actuated orientation means in a dimensionally and thermally stable manner through a gravity formed accumulation loop sized in accordance with said predetermined throw length;
substantially immediately and in synchronism with said orientation means transferring a said throw length of oriented web from said orientation means onto a downstream transfer means while maintaining the dimensional integrity of said web; and forming products in said intermittently advanced lengths of said web on said transfer means substantially immediately upon the completion of each advance to enhance thermal stability therein and preserve said orientation.
15. The method of claim 14, which further includes:
separating formed products from the remainder of said web; and recycling said remainder of said web for extrusion back into a said web.
separating formed products from the remainder of said web; and recycling said remainder of said web for extrusion back into a said web.
16. The method of claim 15, wherein said remainder of said web is first granulated during said recycling.
17. The method of claim 14, which further includes:
separating and accumulating said formed products from the remainder of said web;
granulating said remainder of said web; and recycling said granulated remainder of said web for extrusion.
separating and accumulating said formed products from the remainder of said web;
granulating said remainder of said web; and recycling said granulated remainder of said web for extrusion.
18. The method of claims 14, 15 or 17 in which the thermoplastic material is polystyrene.
19. The method of claims 14, 15 or 17, wherein in said biaxial orientation means, 50% of the orientation of said predetermined throw lengths of said web in the longitudinal direc-tion is performed both upstream and downstream of the transverse orientation thereof.
20. The method of claims 14, 15 or 17, wherein in said biaxial orientation means, 50% of the orientation of said predtermined throw lengths of said web in the longitudinal direc-tion is performed both upstream and downstream of the transverse orientation thereof; and wherein said thermoplastic material is polystyrene.
21. The method of extruding a web of thermoplastic material in a continuous mode and subsequently orienting and forming molded products therefrom in an intermittent mode without interruption of said continuous mode, comprising:
extruding a web of thermoplastic material and presenting it continuously to an intermittently actuated orientation means at an optimum orientation temperature through a gravity formed accumulator loop accommodating a predetermined throw length of web:
stretch orienting the said predetermined throw length of web to a desired degree in the transverse and longitudinal dimen-sions thereof while said web is in continuous longitudinal motion over a given intermittent actuation cycle of said orientation means;
continuously interfacing and juxtaposing said oriented throw of web during said given actuation cycle with a downstream transfer means synchronized with said orientation means in a dimensionally and thermally stable engagement therewith to preserve the integrity of the orientation and the temperature therein and to establish an intermittent feed mode of said web downstream of said orientation means without disturbing the continuous mode upstream thereof;
said downstream transfer means being the input of an intermittent thermoforming means; and intermittently forming products in said incremental lengths of oriented web within said thermoforming means sub-stantially immediately upon receipt thereof to enhance the thermal stability of said web while preserving the integrity of orientation therein.
extruding a web of thermoplastic material and presenting it continuously to an intermittently actuated orientation means at an optimum orientation temperature through a gravity formed accumulator loop accommodating a predetermined throw length of web:
stretch orienting the said predetermined throw length of web to a desired degree in the transverse and longitudinal dimen-sions thereof while said web is in continuous longitudinal motion over a given intermittent actuation cycle of said orientation means;
continuously interfacing and juxtaposing said oriented throw of web during said given actuation cycle with a downstream transfer means synchronized with said orientation means in a dimensionally and thermally stable engagement therewith to preserve the integrity of the orientation and the temperature therein and to establish an intermittent feed mode of said web downstream of said orientation means without disturbing the continuous mode upstream thereof;
said downstream transfer means being the input of an intermittent thermoforming means; and intermittently forming products in said incremental lengths of oriented web within said thermoforming means sub-stantially immediately upon receipt thereof to enhance the thermal stability of said web while preserving the integrity of orientation therein.
22. The method of claim 21, which includes the further steps of:
cooling the formed products and the web in the inter-mittent forming means;
stripping said formed products and the remainder of said web from said forming means.
cooling the formed products and the web in the inter-mittent forming means;
stripping said formed products and the remainder of said web from said forming means.
23. The method of claim 22, which includes the further steps of:
separating the formed products from remainder of said web; and recycling remainder of said web for further extrusion.
separating the formed products from remainder of said web; and recycling remainder of said web for further extrusion.
24. The method of claim 23, which further includes stack-ing the formed products separated from remainder of said web.
25. The method of claim 21, which includes the further steps of:
cooling the formed products and the web in the inter-mittent forming means;
separating the formed products from the remainder of said web; and recycling remainder of said web for further extrusion.
cooling the formed products and the web in the inter-mittent forming means;
separating the formed products from the remainder of said web; and recycling remainder of said web for further extrusion.
26. The method of claim 25, which further includes stack-ing the formed products separated from remainder of said web.
27. The method of claims 21, 22 or 25, wherein the thermoplastic material is polystyrene.
28. The method of claims 21, 22 or 25, wherein in said biaxial orientation means, 50% of the orientation of said predetermined throw lengths of said web in the longitudinal direc-tion is performed both upstream and downstream of the transverse orientation thereof.
29. The method of claims 21, 22 or 25, wherein in said biaxial orientation means, 50% of the orientation of said prede-termined throw lengths of said web in the longitudinal direction is performed both upstream and downstream of the transverse orientation thereof; and wherein said thermoplastic material is polystyrene.
30. Manufacturing means for extruding and presenting a continuous web of thermoplastic material in a continuous mode and transferring incremental lengths thereof to an orienting and forming device and forming products in the latter in an intermittent mode downstream of and with no effect on said continuous mode, comprising:
first means continuously extruding and presenting a web of thermoplastic material at a temperature suitable for subsequent orientation to an accumulation position;
interface means continuously ingesting said extruded web from said extruding and presenting means and intermittently dis-charging predetermined throw lengths of said web;
orientation means intermittently receiving said prede-termined throw lengths of said web and continuously biaxially orienting said web over each said throw length;
each said throw length corresponding to a given actuation cycle of said intermittent orientation means; and thermoformer means downstream of said orientation means and synchronized therewith to ingest each said throw length of biaxially oriented web and form products therein.
first means continuously extruding and presenting a web of thermoplastic material at a temperature suitable for subsequent orientation to an accumulation position;
interface means continuously ingesting said extruded web from said extruding and presenting means and intermittently dis-charging predetermined throw lengths of said web;
orientation means intermittently receiving said prede-termined throw lengths of said web and continuously biaxially orienting said web over each said throw length;
each said throw length corresponding to a given actuation cycle of said intermittent orientation means; and thermoformer means downstream of said orientation means and synchronized therewith to ingest each said throw length of biaxially oriented web and form products therein.
31. The manufacturing means of claim 30, wherein said first means includes thermal stabilizing roller means transferring said web from said extruder to said accumulation position;
wherein said orientation means includes input roller means transversely engaging said web and imparting longitudinal stretch thereto;
said input roller means being intermittently actuated to intermittently ingest a given throw length of said web from said interface means previously and continuously supplied to the latter by said thermal stabilizing roller means;
said interface means comprising an open loop of said web extending from the downstream end of said thermal stabilizing roller means to the upstream end of said input roller means and said loop assuming a sagging mode in a length substantially equal to said throw length between successive actuation cycles of said orientation means in response to the respective feed rates of said thermal stabilizing roller means and said input roller means.
wherein said orientation means includes input roller means transversely engaging said web and imparting longitudinal stretch thereto;
said input roller means being intermittently actuated to intermittently ingest a given throw length of said web from said interface means previously and continuously supplied to the latter by said thermal stabilizing roller means;
said interface means comprising an open loop of said web extending from the downstream end of said thermal stabilizing roller means to the upstream end of said input roller means and said loop assuming a sagging mode in a length substantially equal to said throw length between successive actuation cycles of said orientation means in response to the respective feed rates of said thermal stabilizing roller means and said input roller means.
32. The manufacturing means of claim 31, wherein said orienta-tion means includes transverse orienting means downstream from said input roller means and output roller means downstream from said transverse orienting means;
said output roller means discharging an oriented throw length of said web downstream thereof for each actuation cycle of said orientation means; and wherein said thermoformer means includes transfer means immediately proximate said output roller means and synchronized therewith to receive and ingest said oriented throw lengths of web into said thermoformer in a dimensionally and thermally stable manner.
said output roller means discharging an oriented throw length of said web downstream thereof for each actuation cycle of said orientation means; and wherein said thermoformer means includes transfer means immediately proximate said output roller means and synchronized therewith to receive and ingest said oriented throw lengths of web into said thermoformer in a dimensionally and thermally stable manner.
33. The manufacturing means of claim 32, wherein said output roller means includes enlarged upstream roll means and relatively small downstream roll means;
said output roll means being so dimensioned as to retain a substantially oriented throw length of web thereon between successive actuation cycles of said orientation means in a dimensionally and thermally stable state.
said output roll means being so dimensioned as to retain a substantially oriented throw length of web thereon between successive actuation cycles of said orientation means in a dimensionally and thermally stable state.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000378800A CA1146324A (en) | 1981-06-01 | 1981-06-01 | Method and apparatus for the continuous formation of biaxially oriented thermoplastic materials and forming articles therefrom by intermittent forming means interfaced therewith |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000378800A CA1146324A (en) | 1981-06-01 | 1981-06-01 | Method and apparatus for the continuous formation of biaxially oriented thermoplastic materials and forming articles therefrom by intermittent forming means interfaced therewith |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1146324A true CA1146324A (en) | 1983-05-17 |
Family
ID=4120114
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000378800A Expired CA1146324A (en) | 1981-06-01 | 1981-06-01 | Method and apparatus for the continuous formation of biaxially oriented thermoplastic materials and forming articles therefrom by intermittent forming means interfaced therewith |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1146324A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6136396A (en) * | 1996-08-12 | 2000-10-24 | Tenneco Packaging Inc. | Polymeric articles having antistatic properties and methods for their manufacture |
-
1981
- 1981-06-01 CA CA000378800A patent/CA1146324A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6136396A (en) * | 1996-08-12 | 2000-10-24 | Tenneco Packaging Inc. | Polymeric articles having antistatic properties and methods for their manufacture |
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