CA1290873C - Bimodal star-block copolymers, showing excellent optical properties and resilience, and process for their manufacture - Google Patents
Bimodal star-block copolymers, showing excellent optical properties and resilience, and process for their manufactureInfo
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- CA1290873C CA1290873C CA000542131A CA542131A CA1290873C CA 1290873 C CA1290873 C CA 1290873C CA 000542131 A CA000542131 A CA 000542131A CA 542131 A CA542131 A CA 542131A CA 1290873 C CA1290873 C CA 1290873C
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- star
- block copolymer
- blocks
- bimodal
- copolymer according
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Classifications
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F293/00—Macromolecular compounds obtained by polymerisation on to a macromolecule having groups capable of inducing the formation of new polymer chains bound exclusively at one or both ends of the starting macromolecule
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G81/00—Macromolecular compounds obtained by interreacting polymers in the absence of monomers, e.g. block polymers
- C08G81/02—Macromolecular compounds obtained by interreacting polymers in the absence of monomers, e.g. block polymers at least one of the polymers being obtained by reactions involving only carbon-to-carbon unsaturated bonds
- C08G81/021—Block or graft polymers containing only sequences of polymers of C08C or C08F
- C08G81/022—Block or graft polymers containing only sequences of polymers of C08C or C08F containing sequences of polymers of conjugated dienes and of polymers of alkenyl aromatic compounds
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F297/00—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer
- C08F297/02—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the anionic type
- C08F297/04—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the anionic type polymerising vinyl aromatic monomers and conjugated dienes
- C08F297/044—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the anionic type polymerising vinyl aromatic monomers and conjugated dienes using a coupling agent
Abstract
ABSTRACT OF THE DISCLOSURE:
Bimodal star-block copolymers are disclosed, containing from 60 to 90% by weight of an aromatic vinyl monomer and from 40 to 10% by weight of a conjugated diene, these copolymers having the general formula:
(S - S1 - B/S2 - B1)m - X - (B1 - S2/B - S1)n wherein X is a polyfunctional redical, m and n are integers (being m ? n) the sum of which is between 3 and 20 and equal to the functionality degree of the radical X, S and S1 are polymer blocks of an aromatic vinyl monomer, B1 is an elastomeric copolymer of conjugated dienic units, containing up to 20% of all the dienic units of the copolymer, and B/S2 and S2/B are blocks of copolymers of aromatic vinyl monomer and conjugated diene of the ramdom and/or tapered type. The copolymers according to the invention are thermoplastic, wholly transparent, highly resilient, that is impact-resistant, and show excellent optical properties.
Bimodal star-block copolymers are disclosed, containing from 60 to 90% by weight of an aromatic vinyl monomer and from 40 to 10% by weight of a conjugated diene, these copolymers having the general formula:
(S - S1 - B/S2 - B1)m - X - (B1 - S2/B - S1)n wherein X is a polyfunctional redical, m and n are integers (being m ? n) the sum of which is between 3 and 20 and equal to the functionality degree of the radical X, S and S1 are polymer blocks of an aromatic vinyl monomer, B1 is an elastomeric copolymer of conjugated dienic units, containing up to 20% of all the dienic units of the copolymer, and B/S2 and S2/B are blocks of copolymers of aromatic vinyl monomer and conjugated diene of the ramdom and/or tapered type. The copolymers according to the invention are thermoplastic, wholly transparent, highly resilient, that is impact-resistant, and show excellent optical properties.
Description
3~
~IELD OF THE IN~ENTION
The present invention relates to new bimodal star-block copolymers showing excellent optical properties and S resilience, and to process for their manufacture.
BACRGROUND OF THE INVENTION
Bimodal star-block copolymers are well known in the field of anionic polymerization. These copolymers are generally prepared forming first a linear block-copolymer bearing active lithium atoms on one end of the chain; these linear tactive) polymeric chains are then coupled, by - ,~
" ~,.2~1087 addition of a polyfunctional compound having at least three reactive sites able to react with the C-Li bond of each polymeric chain, by coupling the polymeric chains to the functional groups of said compound.
U.S. Patent 3,280,084 discloses the polymerization of butadiene with buthyl-lithium as initiator to form blocks of polybutadiene ending with lithium9 which (after having been coupled with divinyl-benzene) gives rise to star copolymers having a poly-divinyl-benzene nucleus and several identical polybutadiene arms departing therefrom;
these arms can be styrene-butadiene copolymers of the "random" or "block" type.
U.S. Patent 3,6399517 d;scloses star-block copolymers where the side arms attached to the same nucleus have a different molecular weight.
These arms are formed by using differential additions of styrene monomer and of initiator to give S-Li, Sl-Li and S2-Li, where S, 51 and S2 are polystyrene blocks having a different molecular weight, then adding butadiene and finally coupling these arms to give star-block copolymers having a bi-, tri and poly-modal distribution of the molecular weight.
U.S. Patent 4,086,298 discloses star-block copolymers having a mixture of arms, some of which are formed by polymerizing styrene with alkyl-lithium to form polymeric S-Li blocks and then adding a styrene-butadiene mixture to form a "tapered" polymer represented by S-B-4Sl, wherein the arro~ represents a "tapered" segment. Other arms cons;st of one single butadiene-styrene tapered copolymer segment (B- Sl).
(V-112-02) Z9~.3 U.S Patent 4,221,88~ describes star and bimodal block copolymers, that are transparent and impact resistant, expecially at the low temperatures, such as between -20 and -40C, having general formula:
(S-S'/B- e ~ ) - x - ( B'-B/S') (I) m n where S is a non elastomeric block of 80-g5% by weight of the total mono-vinyl aromatic compound, S'/B or e/S' is a bloc~ copolymer of "random" and/or "tapered" type of the mono-~inyl aromatic compound and of the conjugated diene, wherein the S'/B weight ratio is lower than 1, B' is an elastomeric segment of conjugated polydiene, containing 20-40% by weight of the total conjugated diene, m and n are integers comprised bet~leen 3 and 20 and X is the radical of a polyfunctional coupling agent forming the nucleus of the star-block copolymer. These star-block copolymers, although endowed with very good high impact features, are not wholly satisfactory as to their optical properties.
The Applicant has now obtained bimodal star-block copolymers having excellent optical features, combined with satisfactory high imp~ct features, by introducing in the copolymer a structural modification and reducing the amount of conjugated diene in the B' segment of the general formula ~I).
DISCLOSURE OF THE INVENTIO~
In its broadest aspect, the invention concerns bimodal star-block copolymers containing from 60 to 90% by weisht of recurring units of mono-vinyl aromatic monomer and from 40 to 10% by weight of recurring units of (V-112-02) ~ ~9~ 8~7 ~
conjugated diene, having formula:
(S-Sl-B/S2-Bl)m -X-(B~-S2/B Sl)n wherein X is a polyfunctional radical, m and n are integers (being m n) the sum of which is between 3 and 20 and equal to the functionality degree of the radical X~ S and Sl are polymer blocks of an aromatic vinyl monomer, Bl is an elastomeric copolymer of conjugated dienic units, containin~ up to 20% of all the dienic units of the compolymer, and B/S2 and S2/B are blocks of the "random"
and/or "tapered" type of the mono-vinyl aromatic compound and of the conjugated diene.
The "bimodal" adjective, as it is used in the pr~sent description and claims, indicates a copolymer containing two types of polymeric chains of different lenght between them, respectively indicated by S-Sl-B/S2-Bl and Sl-B/S2-Bl. ~;
According to a preferred embodiment of the invention, styrene blocks S contain a number of units from 3 to 7 times higher than blocks Sl and the sum Sl + S2 contains from 50 to 80% of all the styrene units of the copolymer, e/S2 and S2/~ blocks own a S2:B weight ratio comprised between 0.8 and 1.2, and preferably equal to 1.
Furthermore, we particularly prefer those products, where the ratio of the molecular weight of S to the molecular weight of B/S2 is higher than 1, such as between 1.2 and 6 and preferably between 1.5 and 3.
The amount of conjugated diene units contained in the elastomeric (Bl) block is generally lower than 20% of all the dienic units contained in the copolymer and is (V-112-02) preferably comprised between 1 and 10%.
The copolymers according to the invention are thermoplastic, wholly transparent, highly resilient, that is impact-resistant and sho~J excellent optical properties.
The invention relates aiso to a multi-stage process for the ~anifacture of the new copolymers.
In a first step, 20-50% by weight of the total amount of the mono-vinyl aromatic monomer is anionically polymerized, in an inert solvent and in the presence of an organo-metallic lithium catalyst (initiator), in order to form living linear polymeric blocks bearing lithium ions at the end of the chain. The polymerization is then continued until completion.
In a second step, a further amount of initiator is added and then a second amount of mono-vlnyl aromatic monomer is added, so as to form S-Sl -Li and Sl-Li polymeric blocl~s.
In a third step, a mixture containing all the remaining mono-vinyl aromatic monomer and an amount of conjugated diene at least corresponding to B0% of the total diene is continuously added; in this third step, the polymeric blocks of the RANDOrl and/or TAPERED type (B/S2) are formed.
In a fourth step, all the remaining conjugated diene is added and it is allowed to react until complete conversion, to form a block of polydiene on each of the blocks of the third step. Thus, the mixture contains S-Sl-B/S2-Li and Sl-B/S2-Bl-Li blocks.
In a fifth step, the polifunctional coupling agent is added, which couples S-Sl-B/S2-Bl-Li and Sl-8/S2-Bl-Li (V-112-02) .3 blocics, to give the star-block copo1ymers of formula (II).
; As an initiator, the generally used lithium alkyl, cycloalkyl or aryl compounds can be used, such as for instance methyl-lithium, n-butyl-lithium, sec-butyl-lithium, cyclohexyl-lithium, phenyl-lithium, p-tolyl-lithium and naphthyl-lithium. The amount is generally comprised between 0.2 and 20 millimols per mole of monomer, in the first and second stage. The amount of initiator,in the second stage, is at least in a 1:1 ratio (and preferably the treble) to the amount of the preceding step As a polyfunctional coupling agent, any compound can be used having functional groups able to react with lithium-carbonium bonds, in order to link the carbon atom chain to the polyfunctional group. Typical examples of polyfunctional coupling agents are the polyepoxides, such as for instance the epoxidized polybutadiene, the epoxidized soia-bean oil, the epoxidized linseed oil, polyesters such as diethyl-adipate, polihalides such as silicon tetrachloride; polyisocyanates such as 1,2,4-benzene-triisocyanate; polyimines; polyaldehydes, polyetones; polyanhydrides such as pyromellitic di-anhydride; polyacid halides, such as mellitic acid chloride and so on; poly-vinyl-aromatic compounds, such as divinyl-benzene, can be also used as coupling agents;
divinyl-benzene polymerizes, forming in situ polyfunctional coupling agents. The coupling must be followed by a termination, generally with methanol, water or carbon dioxide.
Type and amount of coupling agent are depending on (~-112-02) the number of polymeric chains containing the lithium ended ends and on the number of desired arms for each star-block molecule.
Thus, in the case of a for coupling agent having a fixed number of funcional groups ~such as for instance silicon tetrachloride~, an equivalent amount of coupling agent (per each equivalent amount of lithium-ended polymeric chains), gives rise to a 4-arm star-block copolymer. In the a case of difunctional agent, which polymeri2es during the coupling reaction, such as for instance divinyl-benzene, the amount of coupling agent to be used is determined by the reaction conditions (the number of equivalent functional sites being variable).
The most suitable monovinyl-aromatic compound, (for the manufacture of the copolymers of the invention) is styrene; an alkyl substituted styrene having the same copolymerization properties, such as for irstance methyl-styrenes, ethyl-styrenes, t.-butyl-styrenes etc., can also be used.
Conjugated dienes useful for preparing the copolymers of the invention are those having from 4 to 8 C
atoms in the molecule, such as for instance l,3-butadienej isoprene, 2,3-dimethyl-1,3-butadine, piperylene and mixture thereof.
Lithium-organic initiators which may be used are the ~ell-~no~ln lithium-alkyl compound such as methyl-lithium, n.-buthyl-lithium, sec.-buthyl-lithium, lithium-cyclo-al~yl compounds such as cyclohexyl-lithium and the aryl-lithium compounds such as phenyl-lithium, p-tolyl-lithium, naphthyl-lithium and so on.
(V-112-02) 9~37 The amount of initiator is comprised between 0.2 and 20 millimols per each mol of the monomer in each step of the process. Each step can require an amount of initiator equal to or hi~her than that of the preceding stage. The total amount of initiator depends on the molecular weight and on the number of the desired polymeric chains of each type.
The polymerization can be carried out in an inert hydrocarbon solvent such as isobutane, pentane, hexane, cyclo-hexane, benzene, toluene, xylene and the like. The polymerization can be carried out in the absence of air, moisture or other impurities, which, as it is well-known, impair the anionic catalytic system.The polymerization temperature can be ~ept between 0 and 120C, preferably between 40 and 80C.
The following examples illustrate the invention without limiting in any way the scope thereof.
EXA~PLE 1 Into a 5 litre glass reaction vessel, kept at a constant temperature under nitrogen atmosphere and equipped~
with a stirrer, there were loaded 2~00 cm3 of cyclohexane and 0.5 cm of styrene; the mixture was then titrated with sec.-butyl-lithium in cyclohexane (to remove impurities).
The temperature was raised up to SO~C and 3.6 millimols of sec.-butyl-lithium were added, dissolved in 7 cm of cyclohexane. 150 9 of styrene were then loaded and the anionic polymerization was allowed to proceed for 30 minutes keeping the temperature below 60C.
~ he analysis of a sample showed a viscosimeter average molecular weight 41~000. At this point further 11.4 ~V-112-02) .29~373 g millimols of sec.-butyl-lithium (dissolved in Zl cm of cyclohexane) and further 150 9 of styrene were added.
The polymerization went on for further 30 minutes always keeping the temperature below 60C and thereafter 150 9 of styrene and 150 g of butadiene ~lere contemporarily and continuously fed within 90 minutes.
The ~olymerization went on at about 60C for 20 minutes and then the colour of the reaction mixture changed fron yellow (the typical color of butadiene-lithium ending blocks) to orange (the typical colour of styrene-lithium ending blocks). The polymerization then continued for further 30 minutes without any change to colour; 2 9 of butadiene were then added by continuing the polymerization for 20 minutes always at ~0C.
At this point 1.9 9 of epoxidized soia-bean oil known on the market as ESTABEX 2307 were added. The reaction mixture was heated at 7~C for 15 minutes and the polymer was separated by precipitation in methanol. The thus obtained copolymer was stabilized by adding 3 9 of 2 6-di ter.-butyl-paracresol and 3 9 of tri-isodecyl phosphite.
600 9 of the obtained product were analyzed and resulted to own about 3 linear arms showing a bimodal distribution in the molecular weight before coupling.
Polystyrene longest blocks (S) had a molecular weight of about 50 000; shortest polystyrene blocks (51) had a molecular weight of 10 000; the styrene/butadiene (B/52) random copolymers had a molecular weight of 20 000 and the polybutadiene Bl blocks a molecular weight of 1~000.
Avera~e molecular weights were determined by Gel-* trademarl~
9~38~3 Permeation" chromatography, using polystyrene as a standard.
The average composition of the obtained star-block copolymer obtained was as follows:
- 75,c by weight styrene, 67% of which as polystyrene (S+Sl) blocks and 33C,'c in the styrene/butadiene (B/S2) copolymer blocks, - 25% by weight of butadiene.
Example 1 was repeated, replacing the epoxidized soia-bean oil by a coupling agent consisting of 15.2 millimols of divinylbenzene (mixture of isomers), coupling occurred within 1 h at 50C. The reaction was completed using 10 cm of ~ater, saturated with carbon dioxide. The star copolymer was separated and stabilized as in example l; the features of the copolymer are reported in table 1.
EXA~lPLE 3 _ Example 1 was repeated by replacing the epoxidized soia-bean oil by 2.B g of epoxidized linseed oil, ~nown on the market as EDE~OL* B-316; the features of the thus obtained product are recorded on Table 1.
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~IELD OF THE IN~ENTION
The present invention relates to new bimodal star-block copolymers showing excellent optical properties and S resilience, and to process for their manufacture.
BACRGROUND OF THE INVENTION
Bimodal star-block copolymers are well known in the field of anionic polymerization. These copolymers are generally prepared forming first a linear block-copolymer bearing active lithium atoms on one end of the chain; these linear tactive) polymeric chains are then coupled, by - ,~
" ~,.2~1087 addition of a polyfunctional compound having at least three reactive sites able to react with the C-Li bond of each polymeric chain, by coupling the polymeric chains to the functional groups of said compound.
U.S. Patent 3,280,084 discloses the polymerization of butadiene with buthyl-lithium as initiator to form blocks of polybutadiene ending with lithium9 which (after having been coupled with divinyl-benzene) gives rise to star copolymers having a poly-divinyl-benzene nucleus and several identical polybutadiene arms departing therefrom;
these arms can be styrene-butadiene copolymers of the "random" or "block" type.
U.S. Patent 3,6399517 d;scloses star-block copolymers where the side arms attached to the same nucleus have a different molecular weight.
These arms are formed by using differential additions of styrene monomer and of initiator to give S-Li, Sl-Li and S2-Li, where S, 51 and S2 are polystyrene blocks having a different molecular weight, then adding butadiene and finally coupling these arms to give star-block copolymers having a bi-, tri and poly-modal distribution of the molecular weight.
U.S. Patent 4,086,298 discloses star-block copolymers having a mixture of arms, some of which are formed by polymerizing styrene with alkyl-lithium to form polymeric S-Li blocks and then adding a styrene-butadiene mixture to form a "tapered" polymer represented by S-B-4Sl, wherein the arro~ represents a "tapered" segment. Other arms cons;st of one single butadiene-styrene tapered copolymer segment (B- Sl).
(V-112-02) Z9~.3 U.S Patent 4,221,88~ describes star and bimodal block copolymers, that are transparent and impact resistant, expecially at the low temperatures, such as between -20 and -40C, having general formula:
(S-S'/B- e ~ ) - x - ( B'-B/S') (I) m n where S is a non elastomeric block of 80-g5% by weight of the total mono-vinyl aromatic compound, S'/B or e/S' is a bloc~ copolymer of "random" and/or "tapered" type of the mono-~inyl aromatic compound and of the conjugated diene, wherein the S'/B weight ratio is lower than 1, B' is an elastomeric segment of conjugated polydiene, containing 20-40% by weight of the total conjugated diene, m and n are integers comprised bet~leen 3 and 20 and X is the radical of a polyfunctional coupling agent forming the nucleus of the star-block copolymer. These star-block copolymers, although endowed with very good high impact features, are not wholly satisfactory as to their optical properties.
The Applicant has now obtained bimodal star-block copolymers having excellent optical features, combined with satisfactory high imp~ct features, by introducing in the copolymer a structural modification and reducing the amount of conjugated diene in the B' segment of the general formula ~I).
DISCLOSURE OF THE INVENTIO~
In its broadest aspect, the invention concerns bimodal star-block copolymers containing from 60 to 90% by weisht of recurring units of mono-vinyl aromatic monomer and from 40 to 10% by weight of recurring units of (V-112-02) ~ ~9~ 8~7 ~
conjugated diene, having formula:
(S-Sl-B/S2-Bl)m -X-(B~-S2/B Sl)n wherein X is a polyfunctional radical, m and n are integers (being m n) the sum of which is between 3 and 20 and equal to the functionality degree of the radical X~ S and Sl are polymer blocks of an aromatic vinyl monomer, Bl is an elastomeric copolymer of conjugated dienic units, containin~ up to 20% of all the dienic units of the compolymer, and B/S2 and S2/B are blocks of the "random"
and/or "tapered" type of the mono-vinyl aromatic compound and of the conjugated diene.
The "bimodal" adjective, as it is used in the pr~sent description and claims, indicates a copolymer containing two types of polymeric chains of different lenght between them, respectively indicated by S-Sl-B/S2-Bl and Sl-B/S2-Bl. ~;
According to a preferred embodiment of the invention, styrene blocks S contain a number of units from 3 to 7 times higher than blocks Sl and the sum Sl + S2 contains from 50 to 80% of all the styrene units of the copolymer, e/S2 and S2/~ blocks own a S2:B weight ratio comprised between 0.8 and 1.2, and preferably equal to 1.
Furthermore, we particularly prefer those products, where the ratio of the molecular weight of S to the molecular weight of B/S2 is higher than 1, such as between 1.2 and 6 and preferably between 1.5 and 3.
The amount of conjugated diene units contained in the elastomeric (Bl) block is generally lower than 20% of all the dienic units contained in the copolymer and is (V-112-02) preferably comprised between 1 and 10%.
The copolymers according to the invention are thermoplastic, wholly transparent, highly resilient, that is impact-resistant and sho~J excellent optical properties.
The invention relates aiso to a multi-stage process for the ~anifacture of the new copolymers.
In a first step, 20-50% by weight of the total amount of the mono-vinyl aromatic monomer is anionically polymerized, in an inert solvent and in the presence of an organo-metallic lithium catalyst (initiator), in order to form living linear polymeric blocks bearing lithium ions at the end of the chain. The polymerization is then continued until completion.
In a second step, a further amount of initiator is added and then a second amount of mono-vlnyl aromatic monomer is added, so as to form S-Sl -Li and Sl-Li polymeric blocl~s.
In a third step, a mixture containing all the remaining mono-vinyl aromatic monomer and an amount of conjugated diene at least corresponding to B0% of the total diene is continuously added; in this third step, the polymeric blocks of the RANDOrl and/or TAPERED type (B/S2) are formed.
In a fourth step, all the remaining conjugated diene is added and it is allowed to react until complete conversion, to form a block of polydiene on each of the blocks of the third step. Thus, the mixture contains S-Sl-B/S2-Li and Sl-B/S2-Bl-Li blocks.
In a fifth step, the polifunctional coupling agent is added, which couples S-Sl-B/S2-Bl-Li and Sl-8/S2-Bl-Li (V-112-02) .3 blocics, to give the star-block copo1ymers of formula (II).
; As an initiator, the generally used lithium alkyl, cycloalkyl or aryl compounds can be used, such as for instance methyl-lithium, n-butyl-lithium, sec-butyl-lithium, cyclohexyl-lithium, phenyl-lithium, p-tolyl-lithium and naphthyl-lithium. The amount is generally comprised between 0.2 and 20 millimols per mole of monomer, in the first and second stage. The amount of initiator,in the second stage, is at least in a 1:1 ratio (and preferably the treble) to the amount of the preceding step As a polyfunctional coupling agent, any compound can be used having functional groups able to react with lithium-carbonium bonds, in order to link the carbon atom chain to the polyfunctional group. Typical examples of polyfunctional coupling agents are the polyepoxides, such as for instance the epoxidized polybutadiene, the epoxidized soia-bean oil, the epoxidized linseed oil, polyesters such as diethyl-adipate, polihalides such as silicon tetrachloride; polyisocyanates such as 1,2,4-benzene-triisocyanate; polyimines; polyaldehydes, polyetones; polyanhydrides such as pyromellitic di-anhydride; polyacid halides, such as mellitic acid chloride and so on; poly-vinyl-aromatic compounds, such as divinyl-benzene, can be also used as coupling agents;
divinyl-benzene polymerizes, forming in situ polyfunctional coupling agents. The coupling must be followed by a termination, generally with methanol, water or carbon dioxide.
Type and amount of coupling agent are depending on (~-112-02) the number of polymeric chains containing the lithium ended ends and on the number of desired arms for each star-block molecule.
Thus, in the case of a for coupling agent having a fixed number of funcional groups ~such as for instance silicon tetrachloride~, an equivalent amount of coupling agent (per each equivalent amount of lithium-ended polymeric chains), gives rise to a 4-arm star-block copolymer. In the a case of difunctional agent, which polymeri2es during the coupling reaction, such as for instance divinyl-benzene, the amount of coupling agent to be used is determined by the reaction conditions (the number of equivalent functional sites being variable).
The most suitable monovinyl-aromatic compound, (for the manufacture of the copolymers of the invention) is styrene; an alkyl substituted styrene having the same copolymerization properties, such as for irstance methyl-styrenes, ethyl-styrenes, t.-butyl-styrenes etc., can also be used.
Conjugated dienes useful for preparing the copolymers of the invention are those having from 4 to 8 C
atoms in the molecule, such as for instance l,3-butadienej isoprene, 2,3-dimethyl-1,3-butadine, piperylene and mixture thereof.
Lithium-organic initiators which may be used are the ~ell-~no~ln lithium-alkyl compound such as methyl-lithium, n.-buthyl-lithium, sec.-buthyl-lithium, lithium-cyclo-al~yl compounds such as cyclohexyl-lithium and the aryl-lithium compounds such as phenyl-lithium, p-tolyl-lithium, naphthyl-lithium and so on.
(V-112-02) 9~37 The amount of initiator is comprised between 0.2 and 20 millimols per each mol of the monomer in each step of the process. Each step can require an amount of initiator equal to or hi~her than that of the preceding stage. The total amount of initiator depends on the molecular weight and on the number of the desired polymeric chains of each type.
The polymerization can be carried out in an inert hydrocarbon solvent such as isobutane, pentane, hexane, cyclo-hexane, benzene, toluene, xylene and the like. The polymerization can be carried out in the absence of air, moisture or other impurities, which, as it is well-known, impair the anionic catalytic system.The polymerization temperature can be ~ept between 0 and 120C, preferably between 40 and 80C.
The following examples illustrate the invention without limiting in any way the scope thereof.
EXA~PLE 1 Into a 5 litre glass reaction vessel, kept at a constant temperature under nitrogen atmosphere and equipped~
with a stirrer, there were loaded 2~00 cm3 of cyclohexane and 0.5 cm of styrene; the mixture was then titrated with sec.-butyl-lithium in cyclohexane (to remove impurities).
The temperature was raised up to SO~C and 3.6 millimols of sec.-butyl-lithium were added, dissolved in 7 cm of cyclohexane. 150 9 of styrene were then loaded and the anionic polymerization was allowed to proceed for 30 minutes keeping the temperature below 60C.
~ he analysis of a sample showed a viscosimeter average molecular weight 41~000. At this point further 11.4 ~V-112-02) .29~373 g millimols of sec.-butyl-lithium (dissolved in Zl cm of cyclohexane) and further 150 9 of styrene were added.
The polymerization went on for further 30 minutes always keeping the temperature below 60C and thereafter 150 9 of styrene and 150 g of butadiene ~lere contemporarily and continuously fed within 90 minutes.
The ~olymerization went on at about 60C for 20 minutes and then the colour of the reaction mixture changed fron yellow (the typical color of butadiene-lithium ending blocks) to orange (the typical colour of styrene-lithium ending blocks). The polymerization then continued for further 30 minutes without any change to colour; 2 9 of butadiene were then added by continuing the polymerization for 20 minutes always at ~0C.
At this point 1.9 9 of epoxidized soia-bean oil known on the market as ESTABEX 2307 were added. The reaction mixture was heated at 7~C for 15 minutes and the polymer was separated by precipitation in methanol. The thus obtained copolymer was stabilized by adding 3 9 of 2 6-di ter.-butyl-paracresol and 3 9 of tri-isodecyl phosphite.
600 9 of the obtained product were analyzed and resulted to own about 3 linear arms showing a bimodal distribution in the molecular weight before coupling.
Polystyrene longest blocks (S) had a molecular weight of about 50 000; shortest polystyrene blocks (51) had a molecular weight of 10 000; the styrene/butadiene (B/52) random copolymers had a molecular weight of 20 000 and the polybutadiene Bl blocks a molecular weight of 1~000.
Avera~e molecular weights were determined by Gel-* trademarl~
9~38~3 Permeation" chromatography, using polystyrene as a standard.
The average composition of the obtained star-block copolymer obtained was as follows:
- 75,c by weight styrene, 67% of which as polystyrene (S+Sl) blocks and 33C,'c in the styrene/butadiene (B/S2) copolymer blocks, - 25% by weight of butadiene.
Example 1 was repeated, replacing the epoxidized soia-bean oil by a coupling agent consisting of 15.2 millimols of divinylbenzene (mixture of isomers), coupling occurred within 1 h at 50C. The reaction was completed using 10 cm of ~ater, saturated with carbon dioxide. The star copolymer was separated and stabilized as in example l; the features of the copolymer are reported in table 1.
EXA~lPLE 3 _ Example 1 was repeated by replacing the epoxidized soia-bean oil by 2.B g of epoxidized linseed oil, ~nown on the market as EDE~OL* B-316; the features of the thus obtained product are recorded on Table 1.
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l l l l l l l l l l (V-112-02) ~ nn ~ ., .
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Claims (14)
1. A bimodal star-block copolymer, containing from 60 to 90% by weight of recurring units of a mono-vinyl aromatic monomer and from 40 to 10% by weight of recurring units of a conjugated diene, said copolymer being of general formula (II):
(S-S1/S2-B1)m -X-(B1-S2/B-S1)n (II) wherein:
X is a polyfunctional radical, m and n are integers with m ? n and the sum m + n ranging between 3 and 20 and being equal to the functionality degree of the radical X, S and S1 are polymer blocks of an aromatic vinyl monomer, B1 is an elastomeric copolymer block of conjugated dienic units, containing up to 20% of all the dienic units of the copolymer, and B/S2 and S2/B are blocks of the "random" type, the "tapered" type or both of these types, of the mono-vinyl aromatic monomer and of the conjugated diene.
(S-S1/S2-B1)m -X-(B1-S2/B-S1)n (II) wherein:
X is a polyfunctional radical, m and n are integers with m ? n and the sum m + n ranging between 3 and 20 and being equal to the functionality degree of the radical X, S and S1 are polymer blocks of an aromatic vinyl monomer, B1 is an elastomeric copolymer block of conjugated dienic units, containing up to 20% of all the dienic units of the copolymer, and B/S2 and S2/B are blocks of the "random" type, the "tapered" type or both of these types, of the mono-vinyl aromatic monomer and of the conjugated diene.
2. Bimodal star-block copolymer according to claim 1, wherein the elastomeric block (B1) contains from 1 to 10% of all the dienic units of the copolymer.
3. Bimodal star-block copolymer according to claim 1 or 2, wherein the styrene blocks S contain a number of units which is from 3 to 7 times higher than the one of the S1 blocks and wherein the sum of S1 + S2 contains from 50 to 80% of all the styrene units of the copolymer.
4. Bimodal star-block copolymer according to claim 1 or 2, wherein B/S2 and S2/s blocks show a S2:B
weight ratio comprised between 0.8 and 1.2.
weight ratio comprised between 0.8 and 1.2.
5. Bimodal star-block copolymer according to claim 1 or 2, wherein B/S2 and S2/B blocks show a S2:B
weight ratio equal to 1.
weight ratio equal to 1.
6. Bimodal and star-block copolymer according to claim 1, wherein the ratio between the molecular weight of S
and the molecular weight of B/S2 is higher than 1.
and the molecular weight of B/S2 is higher than 1.
7. Bimodal star-block copolymer according to claim 6, wherein the ratio between the molecular weight of S
and the molecular weight of B/S2 is comprised between 1.2 and 6.
and the molecular weight of B/S2 is comprised between 1.2 and 6.
8. Bimodal star-block copolymer according to claim 6, wherein the ratio between the molecular weight of S
and the molecular weight of B/S2 is comprised between 1.5 and 3.
and the molecular weight of B/S2 is comprised between 1.5 and 3.
9. Bimodal star-block copolymer according to claim 1, 2, 6 or 7, wherein the coupling agent is selected from the group consisting of polyepoxides, epoxidized soia-bean oil, epoxidized linseed oil, polyesters, polyhalides, polyanhydrides, polyisocyanates, poly-imines, polyaldehydes, polyketones, polyanhydrides, polyacid halides and poly-vinyl aromatic compounds.
10. Bimodal star-block copolymer according to claim 1, wherein the mono-vinyl aromatic monomer is styrene.
11. Bimodal star-block copolymer according to claim 1 or 10, wherein the conjugated diene has from 4 to 8 carbon atoms.
12. Bimodal star-block copolymer according to claim 1 or 10, wherein the conjugated diene is 1,3-butadiene.
13. Process for the preparation of a bimodal star-block copolymer according to claim 1, comprising the successive step of:
- polymerizing 20-50% by weight of the total amount of mono-vinyl aromatic monomer, by anionic way, in an inert solvent and in the presence of a lithium organo-metallic catalyst used as initiator, to form living linear polymeric blocks (S-Li) bearing lithium ions at the end of the chain;
- adding a further amount of initiator and then a second amount of mono-vinyl aromatic monomer, to form polymeric blocks S-S1-Li and S1-Li;
- adding continuously a mixture containing all the remaining mono-vinyl aromatic monomer and an amount of conjugated diene at least corresponding to 80% of the total diene;
- adding all the remaining conjugated diene and to allow the mixture to polymerize until the conversion is completed to form a polydiene block on each of the blocks of the third step; and - adding the polyfunctional coupling agent which couples S-S1-B/S2-B1Li and S1-B/S2-B1-Li blocks, giving the star-block copolymer of formula (II).
- polymerizing 20-50% by weight of the total amount of mono-vinyl aromatic monomer, by anionic way, in an inert solvent and in the presence of a lithium organo-metallic catalyst used as initiator, to form living linear polymeric blocks (S-Li) bearing lithium ions at the end of the chain;
- adding a further amount of initiator and then a second amount of mono-vinyl aromatic monomer, to form polymeric blocks S-S1-Li and S1-Li;
- adding continuously a mixture containing all the remaining mono-vinyl aromatic monomer and an amount of conjugated diene at least corresponding to 80% of the total diene;
- adding all the remaining conjugated diene and to allow the mixture to polymerize until the conversion is completed to form a polydiene block on each of the blocks of the third step; and - adding the polyfunctional coupling agent which couples S-S1-B/S2-B1Li and S1-B/S2-B1-Li blocks, giving the star-block copolymer of formula (II).
14. Process according to claim 13, wherein the organo metallic catalyst is a lithium-alkyl, lithium cycloalkyl or lithium-aryl compound, in an amount comprised between 0.2 and 20 millimols per mol of the monomer in the first and in the second step.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT21165/86A IT1196517B (en) | 1986-07-17 | 1986-07-17 | RADIAL AND BIMODAL BLOCK COPOLYMERS HAVING EXCELLENT OPTICAL PROPERTIES AND IMPACT RESISTANCE AND PROCESS FOR THEIR PREPARATION |
| IT21165A/86 | 1986-07-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1290873C true CA1290873C (en) | 1991-10-15 |
Family
ID=11177727
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000542131A Expired - Fee Related CA1290873C (en) | 1986-07-17 | 1987-07-15 | Bimodal star-block copolymers, showing excellent optical properties and resilience, and process for their manufacture |
Country Status (11)
| Country | Link |
|---|---|
| US (1) | US4925899A (en) |
| EP (1) | EP0255001A3 (en) |
| JP (1) | JPS6392629A (en) |
| KR (1) | KR880001710A (en) |
| AU (1) | AU601197B2 (en) |
| BR (1) | BR8703704A (en) |
| CA (1) | CA1290873C (en) |
| DK (1) | DK370487A (en) |
| IT (1) | IT1196517B (en) |
| NO (1) | NO168113C (en) |
| ZA (1) | ZA875101B (en) |
Families Citing this family (39)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3738748A1 (en) * | 1987-11-14 | 1989-05-24 | Basf Ag | METHOD FOR THE DISCONTINUOUS MANUFACTURE OF UNSYMMETRICALLY BUILT-ON, STERNOFERMIC BRANCHED BLOCK COPOLYMERISES AND THEIR USE |
| CA2028410C (en) * | 1990-01-02 | 1996-09-17 | William J. Trepka | Tapered block styrene/butadiene copolymers |
| IT1255489B (en) * | 1992-08-05 | 1995-11-06 | Enichem Polimeri | THERMOPLASTIC SHOCKPROOFING MATERIAL FOR MOLDING |
| US5290875A (en) * | 1992-11-30 | 1994-03-01 | Phillips Petroleum Company | Conjugated diene/monovinylarene block copolymers with multiple tapered blocks |
| CA2111062A1 (en) * | 1992-12-23 | 1994-06-24 | George A. Moczygemba | Tapered block copolymers of monovinylarenes and conjugated dienes |
| US5296547A (en) * | 1993-01-28 | 1994-03-22 | Minnesota Mining And Manufacturing Company | Block copolymer having mixed molecular weight endblocks |
| US5412031A (en) * | 1993-05-25 | 1995-05-02 | Minnesota Mining & Manufacturing Company | Multi-arm block copolymers, and pressure sensitive adhesive and tape employing a multi-arm elastomeric block copolymer |
| US5446104A (en) * | 1993-07-12 | 1995-08-29 | Shell Oil Company | Crosslinkable low viscosity star polymer blends |
| US5360875A (en) * | 1993-09-10 | 1994-11-01 | Shell Oil Company | Method for producing coupled asymmetric polymers |
| CA2117708C (en) * | 1993-09-30 | 2002-10-22 | William J. Trepka | Block copolymers of monovinylarenes and conjugated dienes and preparation thereof |
| US6265484B1 (en) * | 1993-11-15 | 2001-07-24 | Phillips Petroleum Company | Tapered block copolymers of monovinylarenes and conjugated dienes |
| CA2134026C (en) * | 1993-11-15 | 1998-06-09 | William J. Trepka | Tapered block copolymers of monovinylarenes and conjugated dienes |
| US5399628A (en) * | 1993-12-02 | 1995-03-21 | Phillips Petroleum Company | Block copolymers of monovinylarenes and conjugated dienes containing two interior tapered blocks |
| FR2714384B1 (en) * | 1993-12-29 | 1996-02-02 | Atochem Elf Sa | Star block copolymer of a vinyl aromatic monomer and of a conjugated diene, process for obtaining it, and the compositions comprising said copolymer and crystal polystyrene. |
| US5438103A (en) * | 1994-03-23 | 1995-08-01 | Phillips Petroleum Company | Block copolymers of monovinylaromatic and conjugated diene monomers |
| US5447995A (en) * | 1994-05-27 | 1995-09-05 | Shell Oil Company | Method for producing asymmetric radial polymers |
| US5550196A (en) * | 1994-11-09 | 1996-08-27 | Shell Oil Company | Low viscosity adhesive compositions containing asymmetric radial polymers |
| US5461116A (en) * | 1994-11-10 | 1995-10-24 | Shell Oil Company | Core functionalized star block copolymers |
| DE19519855A1 (en) * | 1995-05-31 | 1996-12-05 | Basf Ag | Thermoplastic molding compound with high toughness and rigidity |
| US6835778B2 (en) * | 1995-08-29 | 2004-12-28 | Chevron Phillips Chemical Company Lp | Conjugated diene/monovinylarene block copolymers blends |
| US6096828A (en) * | 1995-08-29 | 2000-08-01 | Phillips Petroleum Company | Conjugated diene/monovinylarene block copolymers, methods for preparing same, and polymer blends |
| US6057406A (en) * | 1998-08-03 | 2000-05-02 | The University Of Southern Mississippi | Functionally gradient polymeric materials |
| US6127487A (en) * | 1998-10-14 | 2000-10-03 | Phillips Petroleum Company | Process to produce coupled block copolymers and said copolymers |
| EP1116742A1 (en) * | 2000-01-12 | 2001-07-18 | Fina Research S.A. | S-B-S compositions |
| US6462137B2 (en) * | 2000-10-19 | 2002-10-08 | China Petroleum And Chemical Corporation | Star-block interpolymers and preparation of the same |
| EP1408061A1 (en) * | 2002-10-11 | 2004-04-14 | ATOFINA Research | Process for the production of a transparent copolymer |
| US20050166551A1 (en) * | 2004-02-02 | 2005-08-04 | Keane J. A. | Multilayer high clarity shrink film comprising monovinylarene-conjugated diene copolymer |
| US7348076B2 (en) | 2004-04-08 | 2008-03-25 | Saint-Gobain Ceramics & Plastics, Inc. | Single crystals and methods for fabricating same |
| US20070026251A1 (en) * | 2005-07-26 | 2007-02-01 | Kraton Polymers U.S. Llc | Flexible packaging laminate films including a block copolymer layer |
| US20070078194A1 (en) * | 2005-10-04 | 2007-04-05 | St Clair David J | Flexographic printing plate and flexographic printing plate precursor composition for preparing same |
| US20070078205A1 (en) * | 2005-10-04 | 2007-04-05 | St Clair David J | Hot melt adhesive composition having improved stability |
| US20070078206A1 (en) * | 2005-10-04 | 2007-04-05 | Clair David J S | Sound damping composition |
| US7592390B2 (en) * | 2006-03-24 | 2009-09-22 | Kraton Polymers U.S. Llc | Hydrogenated block copolymer compositions |
| US7582702B2 (en) | 2006-03-24 | 2009-09-01 | Kraton Polymers U.S. Llc | Block copolymer compositons |
| US7858693B2 (en) * | 2006-03-24 | 2010-12-28 | Kratonpolymers U.S. Llc | Unhydrogenated block copolymer compositions |
| US7585916B2 (en) | 2006-03-24 | 2009-09-08 | Kraton Polymers Us Llc | Block copolymer compositions |
| WO2007127155A2 (en) * | 2006-04-24 | 2007-11-08 | Kraton Polymers U.S Llc | Polymeric compositions and films formed therefrom |
| US20100272975A1 (en) * | 2009-04-23 | 2010-10-28 | Chevron Phillips Chemical Company Lp | System and method for the production and use of lamination films |
| WO2015106075A1 (en) * | 2014-01-10 | 2015-07-16 | Tyco Electronics Raychem Bvba | Thermoplastic gel compositions and their methods of making |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4167545A (en) * | 1975-11-08 | 1979-09-11 | Basf Aktiengesellschaft | Branched block copolymers and their manufacture |
| DE2550227C2 (en) * | 1975-11-08 | 1984-12-20 | Basf Ag, 6700 Ludwigshafen | Branched block copolymers and process for their preparation |
| US4180530A (en) * | 1979-02-05 | 1979-12-25 | Arco Polymers, Inc. | Clear impact resistant thermoplastic star-block copolymers |
| US4248982A (en) * | 1979-04-30 | 1981-02-03 | Arco Polymers, Inc. | Clear impact resistant thermoplastic star-block copolymers |
| US4221884A (en) * | 1979-05-14 | 1980-09-09 | Arco Polymers, Inc. | Clear impact resistant thermoplastic star-block copolymers |
| DE3032832A1 (en) * | 1980-08-30 | 1982-04-22 | Basf Ag, 6700 Ludwigshafen | METHOD FOR PRODUCING BRANCHED BLOCK COPOLYMERS, USE THEREOF AND MOLDED PARTS THEREOF |
-
1986
- 1986-07-17 IT IT21165/86A patent/IT1196517B/en active
-
1987
- 1987-07-13 ZA ZA875101A patent/ZA875101B/en unknown
- 1987-07-14 AU AU75653/87A patent/AU601197B2/en not_active Ceased
- 1987-07-15 BR BR8703704A patent/BR8703704A/en not_active IP Right Cessation
- 1987-07-15 CA CA000542131A patent/CA1290873C/en not_active Expired - Fee Related
- 1987-07-16 JP JP62176083A patent/JPS6392629A/en active Pending
- 1987-07-16 KR KR1019870007769A patent/KR880001710A/en not_active Application Discontinuation
- 1987-07-16 NO NO872968A patent/NO168113C/en unknown
- 1987-07-16 DK DK370487A patent/DK370487A/en unknown
- 1987-07-17 EP EP87110387A patent/EP0255001A3/en not_active Ceased
-
1988
- 1988-07-01 US US07/214,831 patent/US4925899A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DK370487A (en) | 1988-01-18 |
| KR880001710A (en) | 1988-04-26 |
| NO168113C (en) | 1992-01-15 |
| IT1196517B (en) | 1988-11-16 |
| BR8703704A (en) | 1988-03-29 |
| NO168113B (en) | 1991-10-07 |
| EP0255001A2 (en) | 1988-02-03 |
| DK370487D0 (en) | 1987-07-16 |
| ZA875101B (en) | 1988-01-13 |
| JPS6392629A (en) | 1988-04-23 |
| NO872968L (en) | 1988-01-18 |
| AU601197B2 (en) | 1990-09-06 |
| EP0255001A3 (en) | 1990-05-16 |
| AU7565387A (en) | 1988-01-21 |
| US4925899A (en) | 1990-05-15 |
| NO872968D0 (en) | 1987-07-16 |
| IT8621165A0 (en) | 1986-07-17 |
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