CA1214592A - Polymeric liquid crystals - Google Patents
Polymeric liquid crystalsInfo
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- CA1214592A CA1214592A CA000431937A CA431937A CA1214592A CA 1214592 A CA1214592 A CA 1214592A CA 000431937 A CA000431937 A CA 000431937A CA 431937 A CA431937 A CA 431937A CA 1214592 A CA1214592 A CA 1214592A
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- Prior art keywords
- film
- hereof
- set forth
- alkylene
- composition
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K19/00—Liquid crystal materials
- C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
- C09K19/36—Steroidal liquid crystal compounds
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K19/00—Liquid crystal materials
- C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
- C09K2019/0444—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit characterized by a linking chain between rings or ring systems, a bridging chain between extensive mesogenic moieties or an end chain group
- C09K2019/0448—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit characterized by a linking chain between rings or ring systems, a bridging chain between extensive mesogenic moieties or an end chain group the end chain group being a polymerizable end group, e.g. -Sp-P or acrylate
Abstract
POLYMERIC LIQUID CRYSTALS
Abstract The present invention concerns novel cholesteric liquid crystalline monomers and combinations thereof with materials that will support formation of a mixture which demonstrates cholesteric liquid crystalline properties. These materials may be formed as films, heated or cooled to a desired temperature to cause the cholesteric film to exhibit a desired optical response, and photopolymerized to essentially fix the optical characteristics of the resulting polymer.
Abstract The present invention concerns novel cholesteric liquid crystalline monomers and combinations thereof with materials that will support formation of a mixture which demonstrates cholesteric liquid crystalline properties. These materials may be formed as films, heated or cooled to a desired temperature to cause the cholesteric film to exhibit a desired optical response, and photopolymerized to essentially fix the optical characteristics of the resulting polymer.
Description
I æ
POLYMERIC LIQUID CRYSTALS
The present invention relates to liquid crystals and more particularly to polymeric liquid crystals which have fixed optical characteristics.
Background of the Invention The distance of liquid crystalline materials has been recognized since the late 1800's. The terms "liquid crystal" or "misogyny" refer to a number of states of matter which lie between solid crystals and isotropic liquids, the latter being randomly ordered Liquid crystalline materials possess some structural characteristics of crystals, yet they may be viscous or quite mobile liquids.
The varying degrees of order which are possessed by liquid crystals give rise to three distinct types of structures called mesophases. A liquid crystal, when in the crystalline state, has a three-dimensional uniform structure with orientation Al and positional order. As the crystal is heated, it may initially lose one dimension of its positional order. This is referred to as the smectic mesophase, a phase in which the liquid crystal retains the orientation Al order of the crystalline state, as well as two directional positional order.
With further heating, the liquid crystal can convert to the pneumatic mesophase. In this phase, the remaining positional order is lost and the liquid crystalline material retains only the one-directional : `:
:
:
: , . .
POLYMERIC LIQUID CRYSTALS
The present invention relates to liquid crystals and more particularly to polymeric liquid crystals which have fixed optical characteristics.
Background of the Invention The distance of liquid crystalline materials has been recognized since the late 1800's. The terms "liquid crystal" or "misogyny" refer to a number of states of matter which lie between solid crystals and isotropic liquids, the latter being randomly ordered Liquid crystalline materials possess some structural characteristics of crystals, yet they may be viscous or quite mobile liquids.
The varying degrees of order which are possessed by liquid crystals give rise to three distinct types of structures called mesophases. A liquid crystal, when in the crystalline state, has a three-dimensional uniform structure with orientation Al and positional order. As the crystal is heated, it may initially lose one dimension of its positional order. This is referred to as the smectic mesophase, a phase in which the liquid crystal retains the orientation Al order of the crystalline state, as well as two directional positional order.
With further heating, the liquid crystal can convert to the pneumatic mesophase. In this phase, the remaining positional order is lost and the liquid crystalline material retains only the one-directional : `:
:
:
: , . .
- 2 - LFM-7211 orientation Al order of the crystalline state. The molecular order ox pneumatic mesophases is characterized by orientation of the molecules along an axis which coincides with the long axis of the molecules. The centers of gravity of the molecules are arranged randomly 80 that no positional long-range order exists.
In the cholesteric mesophase, the molecular order is characterized by orientation of the molecules along an axis which coincides with the long molecular axis as in a pneumatic phase, however, the axis changes direction in a continuous manner along a second axis perpendicular to the first. For this reason, cholesteric mesophases are often referred to as twisted pneumatic mesophases. Optical activity is necessary for a misogynic material to form a cholesteric mesophase.
The term "cholesteric" is primarily of historical significance because the first-discovered liquid crystalline material which exhibited a cholesteric mesophase was cholesterol bonniest. It has long been recognized, however, that the presence of the cholesterol moiety is not required, and that non-cholesterol derivatives may also exhibit a cholesteric mesophase.
The P or art Substantial interest has been shown in liquid crystalline materials which exhibit cholesteric mesophases because these materials exhibit unique optical properties such as selective reflection of visible light to produce iridescent colors, as well as circular dichroism. Thus, for example, US. Patent 3,720,623 discloses mixtures of cholesteric and pneumatic liquid crystals which are useful in temperature-sensitive visual displays; US. Patent
In the cholesteric mesophase, the molecular order is characterized by orientation of the molecules along an axis which coincides with the long molecular axis as in a pneumatic phase, however, the axis changes direction in a continuous manner along a second axis perpendicular to the first. For this reason, cholesteric mesophases are often referred to as twisted pneumatic mesophases. Optical activity is necessary for a misogynic material to form a cholesteric mesophase.
The term "cholesteric" is primarily of historical significance because the first-discovered liquid crystalline material which exhibited a cholesteric mesophase was cholesterol bonniest. It has long been recognized, however, that the presence of the cholesterol moiety is not required, and that non-cholesterol derivatives may also exhibit a cholesteric mesophase.
The P or art Substantial interest has been shown in liquid crystalline materials which exhibit cholesteric mesophases because these materials exhibit unique optical properties such as selective reflection of visible light to produce iridescent colors, as well as circular dichroism. Thus, for example, US. Patent 3,720,623 discloses mixtures of cholesteric and pneumatic liquid crystals which are useful in temperature-sensitive visual displays; US. Patent
3,766,061 discloses decorative films comprising solid materials which are proportioned such that the composition demonstrates cholesteric properties; US. Patent 3,923,685 discloses cholesteric materials which convert to the pneumatic state upon exposure to an electric field;
I
and US. Patent 3,931,041 discloses combinations of pneumatic and potentially cholesteric material which are useful in imaging and display devices.
Although the colored images produced using cholesteric material are quite useful, most such images are not permanent. Accordingly, there has been substantial interest in preparing cholesteric materials in which the color can be fixed. Thus, US. Patent 3,766,061, which was referred to above, discloses decorative films in which the color is fixed by cooling.
In addition, US. Patent 4,293,435 discloses a polymeric liquid crystal in which the color is fixed by lowering the temperature of the polymer below the glass transition temperature, thereby fixing the polymer in the solid state.
The use of temperature changes to fix the color is not always practical, however, and there has been interest in developing cholesteric materials whose color can be fixed by other means, such as by photo polymerization, whereby the resulting fixed color is temperature insensitive. Applicant is aware of only one such polymer. This was reported by a group of Japanese workers who disclosed that poly(gamma-butyl-L-glutamate) in trim ethylene glycol dimethacrylate could be photo polymerized to fix the color such that it was temperature insensitive.
Accordingly, one objective of the present invention is to provide polymeric cholesteric liquid crystalline materials having mixed, essentially temperature-insensitive colors.
Yet another objective of the present invention is to provide combinations of monomeric compounds which provide variable optical responses over a variety of temperature ranges.
Yet another objective of the present invention is to provide polymeric films having fixed colors which are useful in a variety of optical devices.
These and other objectives of the present I, ~2~5~
I
and US. Patent 3,931,041 discloses combinations of pneumatic and potentially cholesteric material which are useful in imaging and display devices.
Although the colored images produced using cholesteric material are quite useful, most such images are not permanent. Accordingly, there has been substantial interest in preparing cholesteric materials in which the color can be fixed. Thus, US. Patent 3,766,061, which was referred to above, discloses decorative films in which the color is fixed by cooling.
In addition, US. Patent 4,293,435 discloses a polymeric liquid crystal in which the color is fixed by lowering the temperature of the polymer below the glass transition temperature, thereby fixing the polymer in the solid state.
The use of temperature changes to fix the color is not always practical, however, and there has been interest in developing cholesteric materials whose color can be fixed by other means, such as by photo polymerization, whereby the resulting fixed color is temperature insensitive. Applicant is aware of only one such polymer. This was reported by a group of Japanese workers who disclosed that poly(gamma-butyl-L-glutamate) in trim ethylene glycol dimethacrylate could be photo polymerized to fix the color such that it was temperature insensitive.
Accordingly, one objective of the present invention is to provide polymeric cholesteric liquid crystalline materials having mixed, essentially temperature-insensitive colors.
Yet another objective of the present invention is to provide combinations of monomeric compounds which provide variable optical responses over a variety of temperature ranges.
Yet another objective of the present invention is to provide polymeric films having fixed colors which are useful in a variety of optical devices.
These and other objectives of the present I, ~2~5~
- 4 - LFM-7211 invention will become apparent from the detailed description of preferred embodiments which follow.
Summary of the Invention The present invention concerns novel cholesteric liquid crystalline monomers and combinations thereof with materials that will support formation of a mixture which demonstrates cholesteric liquid crystalline properties.
These materials may be formed as films, heated or cooled to a desired temperature to cause the cholesteric film to exhibit a desired optical response, and photo polymerized to essentially fix the optical characteristics of the resulting polymer.
Detailed Description of Preferred Embodiments In one embodiment the present invention comprises a composition suitable to provide a polymeric film having fixed optical properties, said composition comprising a-photopolymerizable monomer having the structure-- -Jo kiwi O OILY
YE
where Al = En or SHEA, A = -R2-, R30 or 4 R2 = an alkaline chain having 3-14 ethylene or lower alkyl-substituted ethylene groups, R3 = an alkaline chain having from 2~14 ethylene or lower alkyd-substituted ethylene groups, R4 = an alkaline or lower alkyl-substituted alkaline ether, dither or triether having a total of from 3-14 carbon atoms in the alkaline linkages, provided that the terminal alkaline linkage adjacent the carbonate moiety comprises not less than I
- _ 5- LFM-7211 two carbon atoms and y = O or l; and a suitable photoinitia~or.
In a second embodiment, the present invention comprises a polymeric film having a fixed optical response, said film being obtained by photo polymerizing a composition comprising a photopolymerizable monomer having the structure SCHICK
Y -1 H or SHEA, A = -R2-, -R O or R O
R2 = an alkaline chain having from 3-14 ethylene or lower alkyl-substituted ethylene groups, R3 = an alXylene chain having from 2-14 ethylene or lower alkyl-substituted ethylene groups, R4 = an alkaline or lower alkyl-substituted alkaline ether, dither or triether having a total of from 3-14 carbon atoms in the alkaline linkages, provided that the terminal alkaline linkage adjacent the carbonate moiety comprises not less than two carbon atoms and y = O or l; and a suitable photo initiator.
In a third embodiment the present invention comprises a process for preparing films comprising polymeric liquid crystalline materials having a fixed optical response, said process comprising the steps of preparing a film comprising a photopolymerizable monomer having the structure .
.
, ye SCHICK lo H
H
where Al = H or C~3, A = -R2-, -R30- or -R40-, R2 = an alkaline chain having from 3-14 ethylene or lower alkyl-substituted ethylene groups, R3 = an alkaline chain having from 2-14 ethylene or lower alkyd-substituted ethylene groups, R4 = an alkylene-or lower alkyl-substituted alkaline ether, dither or triether having a total of from 3 14 carbon atoms in the alkaline linkages, provided that the terminal alkaline linkage adjacent the carbonate moiety comprises not less than two carbon atoms, and y = 0 or 1; and a suitable photo initiator; aligning said film; adjusting the temperature of said film to obtain a desired optical response and photo polymerizing said film The cholesterol derivatives which may be used to practice the present invention are cholesterol (where y =
0) and 5,6-dihydrocholesterol (where y = lo In addition, a number of options are available in the three position side chain. Thus, the polymerizable moiety of the side chain can comprise an acrylate or methacrylate moiety which is bridged to an ester or carbonate linkage. Where an ester linkage it present, the bridge will comprise an alkyd chain comprising from 3-14 ethylene or lower alkyl-substituted ethylene groups. Lower alkyd as used herein shall mean an alkyd group comprising from 1-4 carbon atoms. The methacrylate esters/ where Al = SHEA
and n - 5, 10 and 14, have been reported in the Russian literature; however, these
Summary of the Invention The present invention concerns novel cholesteric liquid crystalline monomers and combinations thereof with materials that will support formation of a mixture which demonstrates cholesteric liquid crystalline properties.
These materials may be formed as films, heated or cooled to a desired temperature to cause the cholesteric film to exhibit a desired optical response, and photo polymerized to essentially fix the optical characteristics of the resulting polymer.
Detailed Description of Preferred Embodiments In one embodiment the present invention comprises a composition suitable to provide a polymeric film having fixed optical properties, said composition comprising a-photopolymerizable monomer having the structure-- -Jo kiwi O OILY
YE
where Al = En or SHEA, A = -R2-, R30 or 4 R2 = an alkaline chain having 3-14 ethylene or lower alkyl-substituted ethylene groups, R3 = an alkaline chain having from 2~14 ethylene or lower alkyd-substituted ethylene groups, R4 = an alkaline or lower alkyl-substituted alkaline ether, dither or triether having a total of from 3-14 carbon atoms in the alkaline linkages, provided that the terminal alkaline linkage adjacent the carbonate moiety comprises not less than I
- _ 5- LFM-7211 two carbon atoms and y = O or l; and a suitable photoinitia~or.
In a second embodiment, the present invention comprises a polymeric film having a fixed optical response, said film being obtained by photo polymerizing a composition comprising a photopolymerizable monomer having the structure SCHICK
Y -1 H or SHEA, A = -R2-, -R O or R O
R2 = an alkaline chain having from 3-14 ethylene or lower alkyl-substituted ethylene groups, R3 = an alXylene chain having from 2-14 ethylene or lower alkyl-substituted ethylene groups, R4 = an alkaline or lower alkyl-substituted alkaline ether, dither or triether having a total of from 3-14 carbon atoms in the alkaline linkages, provided that the terminal alkaline linkage adjacent the carbonate moiety comprises not less than two carbon atoms and y = O or l; and a suitable photo initiator.
In a third embodiment the present invention comprises a process for preparing films comprising polymeric liquid crystalline materials having a fixed optical response, said process comprising the steps of preparing a film comprising a photopolymerizable monomer having the structure .
.
, ye SCHICK lo H
H
where Al = H or C~3, A = -R2-, -R30- or -R40-, R2 = an alkaline chain having from 3-14 ethylene or lower alkyl-substituted ethylene groups, R3 = an alkaline chain having from 2-14 ethylene or lower alkyd-substituted ethylene groups, R4 = an alkylene-or lower alkyl-substituted alkaline ether, dither or triether having a total of from 3 14 carbon atoms in the alkaline linkages, provided that the terminal alkaline linkage adjacent the carbonate moiety comprises not less than two carbon atoms, and y = 0 or 1; and a suitable photo initiator; aligning said film; adjusting the temperature of said film to obtain a desired optical response and photo polymerizing said film The cholesterol derivatives which may be used to practice the present invention are cholesterol (where y =
0) and 5,6-dihydrocholesterol (where y = lo In addition, a number of options are available in the three position side chain. Thus, the polymerizable moiety of the side chain can comprise an acrylate or methacrylate moiety which is bridged to an ester or carbonate linkage. Where an ester linkage it present, the bridge will comprise an alkyd chain comprising from 3-14 ethylene or lower alkyl-substituted ethylene groups. Lower alkyd as used herein shall mean an alkyd group comprising from 1-4 carbon atoms. The methacrylate esters/ where Al = SHEA
and n - 5, 10 and 14, have been reported in the Russian literature; however, these
5~2 esters were prepared for use in solution polymerization reactions and where was no appreciation of their utility for preparing photo polymerized films as disclosed herein.
On the other hand, where a carbonate linkage is present, the bridge may be more complex. Thus, it may comprise from 2-14 ethylene or lower alkyl-substituted ethylene groups, or an alkaline or lower alkyd-substituted alkaline ether, dither or triether having a total of from 3-14 carbon atoms in the alkaline linkages, provided that the terminal alkaline linkage adjacent the carbonate moiety comprises not less than two carbon atoms. Examples of ether moieties which may be utilized in practicing the present invention are those which are analogous to ethylene glycol, diethylene glycol, triethylene glycol, tetramethylene glycol, 3,3'-oxybis-l-propanol, 4,4'-oxybis-l-butanol, l,l'-oxybis-2-propanol, and the like.
When in the pure state the compounds of the present invention are somewhat difficult to work with because they tend to crystallize at inopportune moments.
Furthermore, it is difficult to obtain colored polymers from the pure monomers because the majority of them will show either no colored cholesteric mesophase, or a very narrow colored cholesteric mesophase. rrherefore, the pure compounds of the present invention are limited in their ability to produce polymeric films having desirable optical responses.
Surprisingly, it has been discovered that these limitations may be overcome and that colored and uncolored films comprising a compound of the present invention and either another compound of the present invention, or a second material which is suitable to permit formation of a film that exhibits cholesteric liquid crystalline properties, can be prepared and photo polymerized in the presence of a suitable photo initiator, thereby giving films having fixed optical characteristics. If the film is colored, the - T
fixed color will preferably be substantially the sane 25 the color of the unpolymerized film; however, in certain instances, it may be desirable to obtain â polymerized film having a fixed color which differs from that of the unpolymerized film. Thus, all such possibilities are contemplated by the present invention. retails relating to the preparation of the novel compounds used herein are set forth in my Canadian cop ending application Serial No. 431,936.
A preferred method of practicing the present invention involves the preparation of a film which exhibits a desired optical characteristic at a specific temperature. For colored films, this has been conveniently achieved, for example, by preparing a mixture of the materials which provide the cholesteric film and the photo initiator and, optionally, a cross-linking agent, heating the mixture to obtain a viscous liquid; spreading and aligning the liquid between glass plates; submerging the plates in a thermostatic water bath; and adjusting the temperature to obtain a desired color. For uncolored films, the optical characteristics must be determined spectrophotometrically. The film is then irradiated with a suitable radiation source, such as a mercury lamp. The polymeric films thus obtained can remain substantially unchanged even when exposed to high temperatures for several weeks, depending on the character of the second component as discussed in more detail below.
Examples of photo initiators which will be useful to practice the present invention are benzophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy--acetophenone, 2-benzoyloxyacetophenone, 2-chlorothioxanthone and 2-hydroxs~cyclohexyl phenol kitten, all of said compounds being provided by way of illustration and not limitation.
Examples of optional cross-linking gents g~2~4~2 which will be useful to practice the present invention are trimethylolpropane triacylate, trimethylolpropane trimethacrylate, ethyleneglycol diacrylate, ethyleneglycol dimethacrylate, dip and triethyleneglycol diacrylate and dimethacrylate, l,6-hexanediol diacrylate and dimethyacrylate, l,4-butanediol diacrylate and dimethacrylate, similarly substituted acrylamides and methacrylamides, and many others, said examples similarly being provided by way of illustration and not limitation.
A wide variety of combinations may be made to produce films having different optical characteristics, and these will be largely a matter of choice to the artisan. Nevertheless, several generalizations can be made regarding combinations of the novel monomeric compounds as described herein.
First, combinations of similar monomers will give films which exhibit cholesteric mesophases over a temperature range which is comparable to that of the individual monomers. For example, if an acrylate/me-thacrylate pair of cholesterol derivatives is prepared wherein y = O and A = SHEA-, the methacrylate (R1 = SHEA) exhibits a color range (monotropic only) at 55.8-55.3 C, whereas the acrylate (Al = H) exhibits a color range at 57.8-59.2 C. A 1:1 mixture ox the two exhibits a colored mesophase range of 56.5-55.9 C.
Secondly, combinations of similar monomers having very different alkyd chain lengths provide mixtures with substantially broadened mesophase ranges as compared to the individual components. For example, if a pair of acrylate monomers (Al = H and y - O) is prepared wherein one monomer has A = -(SHEA-, and the other monomer has A = -(SHEA-, the first monomer exhibits a color range of 57.8 - 59.2 C whereas the second monomer exhibits no color. A 1:1 mixture of the two exhibits a substantially broader color range of 68 to -15 C, - 15 C
being the lower detection limit ox the I.
testing apparatus which was used. Accordingly, it will be seen that careful mixing o-f monomers can provide mesophases which exhibit full optical response over a variety of temperature ranges.
Thirdly, the addition of small amounts of non-mesogenic materials to a mixture of misogynic materials can lead to substantial changes in the optical response ranges. Thus, for example, the addition of I of a photo initiator or cross-linking agent can cause a downward shift of 10 degrees or more in the color range exhibited by a mixture of the pure misogynic materials.
so indicated above, an alternative method of preparing photo polymerized films having fixed optical properties is by combining a compound of the present invention with a second material which is suitable to permit formation of a film that exhibits cholesteric liquid crystalline properties. It is not necessary that the second component be either polymerizable or misogynic;
nevertheless it is preferred that it be photopolymerizable in order to provide stable polymeric films. A wide variety of materials will be suitable to provide characteristic films. Examples of such materials, which are provided by way of illustration and not limitation are cholesterol oilily carbonate and 2-methyl-1, 4-phenylene-bis (4'-hexyloxybenzoate~, which are misogynic but not polymerizable; p methoxyphenyl-_-(6-methacryloyloxyhexyloxy)benzoate, which is norl-mesogenic but polymerizable; and cholesterol methacrylamido)undecanoate, which is both misogynic and polymerizable. Illustrations of the utility of certain of these compounds are provided in Example 9, below.
The color intensity and uniformity which may be . .
shown by various combinations of the present invention will also be affected by the alignment. Thus, as is well known in the art, some form of mechanical shearing must be provided to yield the colored films. Such alignment has been satisfactorily achieved by .
.
~2~5~12 sandwiching the monomers between glass plates or polyester films.
Although polymerization of the films can be achieved by radical or thermal initiation, either in solution or in bulk, in virtually all instances, no fixed color or optical response is observed. Instead, the polymers formed in solution or in bulk prefer to form colorless smectic mesophases or amorphous polymers.
Accordingly, photo polymerization is required to achieve the objects of the present invention. The way in which photo polymerization is achieved may have an effect on the optical characteristics of the resulting polymer. Thus, where response duplication is desired, it appears desirable to use a high intensity light source which induces rapid polymerization. On the other hand, slower ; polymerization induced by lower intensity light may tend to produce polymeric films in which the response is j shifted toward the red end of the spectrum.
Multi-response films may also be produced according to the present invention by sequential photo polymerization of the unpolymerized films. For example, a colored film can be placed under a mask and irradiated to fix the color of the exposed areas. By removing the mask and changing the temperature of the partially cured film, a color change can be induced in the non-polymerized portion of the film. Upon subsequent irradiation, the second color can be fixed, thereby providing a two-colored film. Of course, this technique may be extended to provide films having multiple optical responses, if desired by the artisan.
The unique ability of films of the present invention to reflect specific wavelengths of light varying from the near ultraviolet region into the infrared region makes them remarkably useful. For example, their insensitivity to changes in temperature makes them especially suitable as filters, such as band pass, notch, and circular polarization filters, in optical devices.
Further, they will be well suited for :
::
~r5;~'.
Lo 72ll use in reflective displays and so-called "SchefLt-r cells." In addition, where the films reflect in the visible spectrum and show bright iridescent colors, they isle be useful as replacements for dyes and pigments.
use for e~arrlple, they will be usable in floor and wall coverings, textiles, mats, paper products, and in the graphic arts in nonconventional inks.
he advantages and attributes of the present invention will become more apparent from the following examples which are intended to illustrate but not to limit the scope of the present invention.
EXAMPLES
Compounds referred to herein by Roman numeral designation have the following structures, the details of their preparation being described in my cop ending application which was referred to above. As used herein, the temperature ranges are melting ranges unless otherwise indicated by an asterisk (*) or by parentheses. An asterisk signifies that the range is a I mesophase range whereas parentheses indicate that the range is a monotropic mesophase range, the latter being measured as the temperature is decreased. With materials that have ascertainable melting ranges, the ; monotropic mesophase range is often below the melting range.
.
Yo-yo I
"
H
Jo H
`:
wow R2 chosen :
.
~Z~4~
I`
elating or espouse Compound Al n_ my Range _ (C) Via 13 10 0~54.5 - 71.5 Vb C~-13 10 0*58 - 64 Vc H 5 0*45.5 - 68.5 Ed SHEA 5 0*48 - 57.5 Vie H 3 068.5 - 70.5 (67.5) Of SHEA 3 0 73 - 74 (56.0) Vg H 3 1 41 - 43 (35.5) Oh SHEA 3 1 43 - 45 (Below RUT) Vi H 10 162.5 - 64.5 (58.0) Oh SHEA 10 1*33.7 - 49.0 MY
SHUCKS -O IX
H
where A = R30 = (Sheehan, or 1`5 R40 = (Shoeshine ; R3_ Melting or Mesophase Compound Rl(CH2JnO y Range I
Ida SHEA 6 0 58.5 - 60 ~51.0) IXb SHEA 2 0 on - 81 (40.1) ; 20 IXc H 2 0 85.5 - 87 (56.0) I; Id H 6 0 *52 - 62 I: :
: :
I`:
R~0 Melting or Mesophase Compound R1( 2 - 2 on -Range (C) Ire SHEA 2 048.5 - 52.9 (33.1) If SHEA 3 no m. pt. (6.5) Example 1 This example sets forth the color ranges of various monomeric esters V of the present invention, measured with a Lutz optical microscope using transmitted light through cross-polars at 250X magnification. A
Mottler FP5 temperature regulator and a Mottler FP52 hot , stage were used to control the temperature, cooling being obtained by passing a nitrogen stream through a dry-ice cooled copper coil and, subsequently, the FP52 hot stage.
Compound Color Range (C) Via 57.8 - 59.2 Vb (55.8 - 55.3) Vc (~8.5 - 33.0) Ed (51.0 - 26.5) Vie No Color Of Jo Color Example 2 This example describes the colored mesophase ranges obtained for mixtures of previously described paired monomers having identical alkyd chain lengths. The measurements were made using the apparatus described in Example 1, by heating a mixture of the monomers to a melt and cooling. The components were 1:1 mixtures by weight.
optical -2 or R30 Response Components n Color Range Range (C) Via - Vb 10 Violet - Red (56.5 - 55-9) Vc - Ed 5 Violet - Orange (50.2 - 29.5) Vie - Of 3 No Color 61.5 Mesophase ; Vg - Oh 3 No Color Not Measured ; Ida - Id 6 Violet-Blue Violet (51 - 1) IXb - IXc 2 No Color 47 Mesophase I' I
- lo - I- L~!:-7211 Example 3 This example describes the colored mesophase ranges obtained for ~wo-component mixtures of previously described monomers having different alkyd chain lengths.
Color measurements were made as described in Example 1.
The components were 1:1 mixtures by weight.
Optical Wrier RHO Response Components n Color Range Range (C)**
Via volt - orange red (68 - -15) Vie 3 Vb 10 green - orange (47.5 - -15) IXc 2 **-15 C is the lower temperature limit of the thermostat Ed water bath.
x mule 4 This example describes the colored mesophase ranges obtained for mixtures ox previously described monomers having different alkyd chain lengths. The mixtures comprised Irgac~re 651 photo initiator and, optionally other indicated components. Irgacure 651 is 2,2-dimethoxy-2-phenyl acetophenone. Color measurements were made using a thermostat Ed water bath.
Optical Response Components Wig Color Range Range (C) Vb 1.0 Vie 1.0 Violet - Red (50 - -5 Photo initiator 0.04 30Vb 0.25 Oh 0025 Blue Green - Red (40 - -5) Photo initiator 0.01 .
. .
* Trademark , Jo 4~2 -, - 16 - LFM-7211 ., ` Optical Jo Response Components Wt.tg) Color Range Range (C) Ed 0.50 ` Of 0.50 Green - Red (45 - 30) Photo initiator 0.02 Vb 0.50 IXb 0.50 Photo initiator 0.02 Orange Green - Red (32 - o) Methyl methacrylate 0.05 Ed 0.40 Vc 0.40 Via 0.20 Violet - Orange (16 - 6) Photoinitator 0.Q2 Trimethylolpropane triacrylate 0.06 Vb 0.5 Ire 0.5 Green - Red (37 - 0) Photo initiator 0.01 Example 5 This example illustrates a colored polymeric film derived from a film comprising a single monomer of the present invention and 1% Irgacure 651 photo initiator. The table lists "apparent absorbency" maximum (I Max, percentage transmittance (IT) and half-width at half-height (HOWE) of the film and the resulting polymer when the film was photo polymerized at an indicated temperature. The polymerizations in this and other examples were achieved by exposing the film to a 450-watt mercury arc lamp for about 30 seconds.
Film Monomeric Film Polymer Temp. Max HOWE Max HOWE
I no IT (no) (no) IT (no) Vg 25 738 53 45 738 55 50 Id I 438 49 27 441 46 33 ~2~5~
E~m~le 6 This e~:arnple illustrates several colored polymeric films derived from indicated monomer compositioll5. All films contained 1% Irgacure 651 photo initiator. Also, fuller of the films contained 3%
trimethylolpropane triacrylate, excluding pair Vb:IXb which contained 3% trimethylolpropane trimethacrylate.
Film Monomeric Film_ _ P lamer _ Composition Temp. Max HOWE Max HOWE
_ y weight) (C)_ (no) IT no) (no) IT (no?
Valve (1:1) 23 505 4918 505 5120 Vb:IXb (1:1) 25.5 58542 21 585 42 21 Vc:IXc (3:1) 25.5 56346 25 568 45 26 Vc:IXc* (1:1) 24.5 95053 50 950 53 50 15 IXc:IXd* (1:1)25.5 1260 59 112 1260 59 112 *Colorless mixture FxaTnple 7 This example illustrates the differently colored polymeric films which may be produced by subjecting a monomeric mixture to different temperatures and then exposing the colored film to US radiation. The monomeric mixture described for this example comprises a lo by eta mixture of compounds Vb and Of. The apparent absorbency maximum and color are reported for each film.
Film Temperature I Max (no) Color . .
485 - blue - Green 515 Green 542 Iamb Green 11 605 Orange A comparably experiment conducted with a 1:1 mixture of compounds Via and Vie gave the following -results:
:' '.
: :
Jo ., : , . .
Film Temp. Max Transmittance HUH
(C)_ no no Color 32 480 47 32 blue 23 505 51 20 Blarney 18 530 48 42 lime-yreen 574 48 40 orange _xample_8 This example illustrates the effect of non~mesogenic materials on a mixture of monomers. A 1:1 ho weight mixture of compounds Vc and Ed Yale a colored mesophase range of 50.2 - 29.5C, as indicated in Example 2. When 2% by weight of a photo initiator was added, the colored Masonic range shifted to 43-20C~
Example 9 This example illustrates polymer films which can be prepared from a compound of the present invention and unrelated materials, as follows:
On the other hand, where a carbonate linkage is present, the bridge may be more complex. Thus, it may comprise from 2-14 ethylene or lower alkyl-substituted ethylene groups, or an alkaline or lower alkyd-substituted alkaline ether, dither or triether having a total of from 3-14 carbon atoms in the alkaline linkages, provided that the terminal alkaline linkage adjacent the carbonate moiety comprises not less than two carbon atoms. Examples of ether moieties which may be utilized in practicing the present invention are those which are analogous to ethylene glycol, diethylene glycol, triethylene glycol, tetramethylene glycol, 3,3'-oxybis-l-propanol, 4,4'-oxybis-l-butanol, l,l'-oxybis-2-propanol, and the like.
When in the pure state the compounds of the present invention are somewhat difficult to work with because they tend to crystallize at inopportune moments.
Furthermore, it is difficult to obtain colored polymers from the pure monomers because the majority of them will show either no colored cholesteric mesophase, or a very narrow colored cholesteric mesophase. rrherefore, the pure compounds of the present invention are limited in their ability to produce polymeric films having desirable optical responses.
Surprisingly, it has been discovered that these limitations may be overcome and that colored and uncolored films comprising a compound of the present invention and either another compound of the present invention, or a second material which is suitable to permit formation of a film that exhibits cholesteric liquid crystalline properties, can be prepared and photo polymerized in the presence of a suitable photo initiator, thereby giving films having fixed optical characteristics. If the film is colored, the - T
fixed color will preferably be substantially the sane 25 the color of the unpolymerized film; however, in certain instances, it may be desirable to obtain â polymerized film having a fixed color which differs from that of the unpolymerized film. Thus, all such possibilities are contemplated by the present invention. retails relating to the preparation of the novel compounds used herein are set forth in my Canadian cop ending application Serial No. 431,936.
A preferred method of practicing the present invention involves the preparation of a film which exhibits a desired optical characteristic at a specific temperature. For colored films, this has been conveniently achieved, for example, by preparing a mixture of the materials which provide the cholesteric film and the photo initiator and, optionally, a cross-linking agent, heating the mixture to obtain a viscous liquid; spreading and aligning the liquid between glass plates; submerging the plates in a thermostatic water bath; and adjusting the temperature to obtain a desired color. For uncolored films, the optical characteristics must be determined spectrophotometrically. The film is then irradiated with a suitable radiation source, such as a mercury lamp. The polymeric films thus obtained can remain substantially unchanged even when exposed to high temperatures for several weeks, depending on the character of the second component as discussed in more detail below.
Examples of photo initiators which will be useful to practice the present invention are benzophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy--acetophenone, 2-benzoyloxyacetophenone, 2-chlorothioxanthone and 2-hydroxs~cyclohexyl phenol kitten, all of said compounds being provided by way of illustration and not limitation.
Examples of optional cross-linking gents g~2~4~2 which will be useful to practice the present invention are trimethylolpropane triacylate, trimethylolpropane trimethacrylate, ethyleneglycol diacrylate, ethyleneglycol dimethacrylate, dip and triethyleneglycol diacrylate and dimethacrylate, l,6-hexanediol diacrylate and dimethyacrylate, l,4-butanediol diacrylate and dimethacrylate, similarly substituted acrylamides and methacrylamides, and many others, said examples similarly being provided by way of illustration and not limitation.
A wide variety of combinations may be made to produce films having different optical characteristics, and these will be largely a matter of choice to the artisan. Nevertheless, several generalizations can be made regarding combinations of the novel monomeric compounds as described herein.
First, combinations of similar monomers will give films which exhibit cholesteric mesophases over a temperature range which is comparable to that of the individual monomers. For example, if an acrylate/me-thacrylate pair of cholesterol derivatives is prepared wherein y = O and A = SHEA-, the methacrylate (R1 = SHEA) exhibits a color range (monotropic only) at 55.8-55.3 C, whereas the acrylate (Al = H) exhibits a color range at 57.8-59.2 C. A 1:1 mixture ox the two exhibits a colored mesophase range of 56.5-55.9 C.
Secondly, combinations of similar monomers having very different alkyd chain lengths provide mixtures with substantially broadened mesophase ranges as compared to the individual components. For example, if a pair of acrylate monomers (Al = H and y - O) is prepared wherein one monomer has A = -(SHEA-, and the other monomer has A = -(SHEA-, the first monomer exhibits a color range of 57.8 - 59.2 C whereas the second monomer exhibits no color. A 1:1 mixture of the two exhibits a substantially broader color range of 68 to -15 C, - 15 C
being the lower detection limit ox the I.
testing apparatus which was used. Accordingly, it will be seen that careful mixing o-f monomers can provide mesophases which exhibit full optical response over a variety of temperature ranges.
Thirdly, the addition of small amounts of non-mesogenic materials to a mixture of misogynic materials can lead to substantial changes in the optical response ranges. Thus, for example, the addition of I of a photo initiator or cross-linking agent can cause a downward shift of 10 degrees or more in the color range exhibited by a mixture of the pure misogynic materials.
so indicated above, an alternative method of preparing photo polymerized films having fixed optical properties is by combining a compound of the present invention with a second material which is suitable to permit formation of a film that exhibits cholesteric liquid crystalline properties. It is not necessary that the second component be either polymerizable or misogynic;
nevertheless it is preferred that it be photopolymerizable in order to provide stable polymeric films. A wide variety of materials will be suitable to provide characteristic films. Examples of such materials, which are provided by way of illustration and not limitation are cholesterol oilily carbonate and 2-methyl-1, 4-phenylene-bis (4'-hexyloxybenzoate~, which are misogynic but not polymerizable; p methoxyphenyl-_-(6-methacryloyloxyhexyloxy)benzoate, which is norl-mesogenic but polymerizable; and cholesterol methacrylamido)undecanoate, which is both misogynic and polymerizable. Illustrations of the utility of certain of these compounds are provided in Example 9, below.
The color intensity and uniformity which may be . .
shown by various combinations of the present invention will also be affected by the alignment. Thus, as is well known in the art, some form of mechanical shearing must be provided to yield the colored films. Such alignment has been satisfactorily achieved by .
.
~2~5~12 sandwiching the monomers between glass plates or polyester films.
Although polymerization of the films can be achieved by radical or thermal initiation, either in solution or in bulk, in virtually all instances, no fixed color or optical response is observed. Instead, the polymers formed in solution or in bulk prefer to form colorless smectic mesophases or amorphous polymers.
Accordingly, photo polymerization is required to achieve the objects of the present invention. The way in which photo polymerization is achieved may have an effect on the optical characteristics of the resulting polymer. Thus, where response duplication is desired, it appears desirable to use a high intensity light source which induces rapid polymerization. On the other hand, slower ; polymerization induced by lower intensity light may tend to produce polymeric films in which the response is j shifted toward the red end of the spectrum.
Multi-response films may also be produced according to the present invention by sequential photo polymerization of the unpolymerized films. For example, a colored film can be placed under a mask and irradiated to fix the color of the exposed areas. By removing the mask and changing the temperature of the partially cured film, a color change can be induced in the non-polymerized portion of the film. Upon subsequent irradiation, the second color can be fixed, thereby providing a two-colored film. Of course, this technique may be extended to provide films having multiple optical responses, if desired by the artisan.
The unique ability of films of the present invention to reflect specific wavelengths of light varying from the near ultraviolet region into the infrared region makes them remarkably useful. For example, their insensitivity to changes in temperature makes them especially suitable as filters, such as band pass, notch, and circular polarization filters, in optical devices.
Further, they will be well suited for :
::
~r5;~'.
Lo 72ll use in reflective displays and so-called "SchefLt-r cells." In addition, where the films reflect in the visible spectrum and show bright iridescent colors, they isle be useful as replacements for dyes and pigments.
use for e~arrlple, they will be usable in floor and wall coverings, textiles, mats, paper products, and in the graphic arts in nonconventional inks.
he advantages and attributes of the present invention will become more apparent from the following examples which are intended to illustrate but not to limit the scope of the present invention.
EXAMPLES
Compounds referred to herein by Roman numeral designation have the following structures, the details of their preparation being described in my cop ending application which was referred to above. As used herein, the temperature ranges are melting ranges unless otherwise indicated by an asterisk (*) or by parentheses. An asterisk signifies that the range is a I mesophase range whereas parentheses indicate that the range is a monotropic mesophase range, the latter being measured as the temperature is decreased. With materials that have ascertainable melting ranges, the ; monotropic mesophase range is often below the melting range.
.
Yo-yo I
"
H
Jo H
`:
wow R2 chosen :
.
~Z~4~
I`
elating or espouse Compound Al n_ my Range _ (C) Via 13 10 0~54.5 - 71.5 Vb C~-13 10 0*58 - 64 Vc H 5 0*45.5 - 68.5 Ed SHEA 5 0*48 - 57.5 Vie H 3 068.5 - 70.5 (67.5) Of SHEA 3 0 73 - 74 (56.0) Vg H 3 1 41 - 43 (35.5) Oh SHEA 3 1 43 - 45 (Below RUT) Vi H 10 162.5 - 64.5 (58.0) Oh SHEA 10 1*33.7 - 49.0 MY
SHUCKS -O IX
H
where A = R30 = (Sheehan, or 1`5 R40 = (Shoeshine ; R3_ Melting or Mesophase Compound Rl(CH2JnO y Range I
Ida SHEA 6 0 58.5 - 60 ~51.0) IXb SHEA 2 0 on - 81 (40.1) ; 20 IXc H 2 0 85.5 - 87 (56.0) I; Id H 6 0 *52 - 62 I: :
: :
I`:
R~0 Melting or Mesophase Compound R1( 2 - 2 on -Range (C) Ire SHEA 2 048.5 - 52.9 (33.1) If SHEA 3 no m. pt. (6.5) Example 1 This example sets forth the color ranges of various monomeric esters V of the present invention, measured with a Lutz optical microscope using transmitted light through cross-polars at 250X magnification. A
Mottler FP5 temperature regulator and a Mottler FP52 hot , stage were used to control the temperature, cooling being obtained by passing a nitrogen stream through a dry-ice cooled copper coil and, subsequently, the FP52 hot stage.
Compound Color Range (C) Via 57.8 - 59.2 Vb (55.8 - 55.3) Vc (~8.5 - 33.0) Ed (51.0 - 26.5) Vie No Color Of Jo Color Example 2 This example describes the colored mesophase ranges obtained for mixtures of previously described paired monomers having identical alkyd chain lengths. The measurements were made using the apparatus described in Example 1, by heating a mixture of the monomers to a melt and cooling. The components were 1:1 mixtures by weight.
optical -2 or R30 Response Components n Color Range Range (C) Via - Vb 10 Violet - Red (56.5 - 55-9) Vc - Ed 5 Violet - Orange (50.2 - 29.5) Vie - Of 3 No Color 61.5 Mesophase ; Vg - Oh 3 No Color Not Measured ; Ida - Id 6 Violet-Blue Violet (51 - 1) IXb - IXc 2 No Color 47 Mesophase I' I
- lo - I- L~!:-7211 Example 3 This example describes the colored mesophase ranges obtained for ~wo-component mixtures of previously described monomers having different alkyd chain lengths.
Color measurements were made as described in Example 1.
The components were 1:1 mixtures by weight.
Optical Wrier RHO Response Components n Color Range Range (C)**
Via volt - orange red (68 - -15) Vie 3 Vb 10 green - orange (47.5 - -15) IXc 2 **-15 C is the lower temperature limit of the thermostat Ed water bath.
x mule 4 This example describes the colored mesophase ranges obtained for mixtures ox previously described monomers having different alkyd chain lengths. The mixtures comprised Irgac~re 651 photo initiator and, optionally other indicated components. Irgacure 651 is 2,2-dimethoxy-2-phenyl acetophenone. Color measurements were made using a thermostat Ed water bath.
Optical Response Components Wig Color Range Range (C) Vb 1.0 Vie 1.0 Violet - Red (50 - -5 Photo initiator 0.04 30Vb 0.25 Oh 0025 Blue Green - Red (40 - -5) Photo initiator 0.01 .
. .
* Trademark , Jo 4~2 -, - 16 - LFM-7211 ., ` Optical Jo Response Components Wt.tg) Color Range Range (C) Ed 0.50 ` Of 0.50 Green - Red (45 - 30) Photo initiator 0.02 Vb 0.50 IXb 0.50 Photo initiator 0.02 Orange Green - Red (32 - o) Methyl methacrylate 0.05 Ed 0.40 Vc 0.40 Via 0.20 Violet - Orange (16 - 6) Photoinitator 0.Q2 Trimethylolpropane triacrylate 0.06 Vb 0.5 Ire 0.5 Green - Red (37 - 0) Photo initiator 0.01 Example 5 This example illustrates a colored polymeric film derived from a film comprising a single monomer of the present invention and 1% Irgacure 651 photo initiator. The table lists "apparent absorbency" maximum (I Max, percentage transmittance (IT) and half-width at half-height (HOWE) of the film and the resulting polymer when the film was photo polymerized at an indicated temperature. The polymerizations in this and other examples were achieved by exposing the film to a 450-watt mercury arc lamp for about 30 seconds.
Film Monomeric Film Polymer Temp. Max HOWE Max HOWE
I no IT (no) (no) IT (no) Vg 25 738 53 45 738 55 50 Id I 438 49 27 441 46 33 ~2~5~
E~m~le 6 This e~:arnple illustrates several colored polymeric films derived from indicated monomer compositioll5. All films contained 1% Irgacure 651 photo initiator. Also, fuller of the films contained 3%
trimethylolpropane triacrylate, excluding pair Vb:IXb which contained 3% trimethylolpropane trimethacrylate.
Film Monomeric Film_ _ P lamer _ Composition Temp. Max HOWE Max HOWE
_ y weight) (C)_ (no) IT no) (no) IT (no?
Valve (1:1) 23 505 4918 505 5120 Vb:IXb (1:1) 25.5 58542 21 585 42 21 Vc:IXc (3:1) 25.5 56346 25 568 45 26 Vc:IXc* (1:1) 24.5 95053 50 950 53 50 15 IXc:IXd* (1:1)25.5 1260 59 112 1260 59 112 *Colorless mixture FxaTnple 7 This example illustrates the differently colored polymeric films which may be produced by subjecting a monomeric mixture to different temperatures and then exposing the colored film to US radiation. The monomeric mixture described for this example comprises a lo by eta mixture of compounds Vb and Of. The apparent absorbency maximum and color are reported for each film.
Film Temperature I Max (no) Color . .
485 - blue - Green 515 Green 542 Iamb Green 11 605 Orange A comparably experiment conducted with a 1:1 mixture of compounds Via and Vie gave the following -results:
:' '.
: :
Jo ., : , . .
Film Temp. Max Transmittance HUH
(C)_ no no Color 32 480 47 32 blue 23 505 51 20 Blarney 18 530 48 42 lime-yreen 574 48 40 orange _xample_8 This example illustrates the effect of non~mesogenic materials on a mixture of monomers. A 1:1 ho weight mixture of compounds Vc and Ed Yale a colored mesophase range of 50.2 - 29.5C, as indicated in Example 2. When 2% by weight of a photo initiator was added, the colored Masonic range shifted to 43-20C~
Example 9 This example illustrates polymer films which can be prepared from a compound of the present invention and unrelated materials, as follows:
6~13 O I S I -clue SHEA A
OH I C-O-- (OH ) -O-CO~-C-~<~-OCH3, B
I
SHEA 2)7 C Cole C
H
Y
' .
I
.
Compound A is a nernatic liquid crystalline retrial which is not capable of participating in a photo polymerization process. Compound B is a nonmesoyenic material that is capable of participating ~;~ 5 in a photo polymerization reaction. Compound C is a cholesteric liquid crystalline material which is not capable of participating in a photo polymerization I reaction. All three are suitable to permit formation of a film that exhibits cholesteric liquid crystalline properties. To illustrate this, films were prepared and photopolyrnerized using 1% Irgacure 651 photo initiator ; and I trimethylolpropane trimethacrylate.
Composition Film Monomeric Film Polymer _ (weight Temp. Max HOWE Max HOWE
I _ ratio) _ I (no)_ % T (no) (no) % T no Via (2:1) 24 355 43 30 350 41 35 Ebb (1:1) 25 388 52 15 400 42 40 Vg:C (4:1) 25 700 51 33 730 55 52 Although the film derived from pair Via demonstrates suitable optical properties, it's not as stable as other films in which both members of the pair are polymerizable. For example, when this polymeric film was heated at 60 C for one day, it underwent crystallization to give an opaque colorless film.
This invention is not restricted solely to the descriptions and illustrations provided above, but encompasses all modifications envisaged by the following claims.
, ' .
OH I C-O-- (OH ) -O-CO~-C-~<~-OCH3, B
I
SHEA 2)7 C Cole C
H
Y
' .
I
.
Compound A is a nernatic liquid crystalline retrial which is not capable of participating in a photo polymerization process. Compound B is a nonmesoyenic material that is capable of participating ~;~ 5 in a photo polymerization reaction. Compound C is a cholesteric liquid crystalline material which is not capable of participating in a photo polymerization I reaction. All three are suitable to permit formation of a film that exhibits cholesteric liquid crystalline properties. To illustrate this, films were prepared and photopolyrnerized using 1% Irgacure 651 photo initiator ; and I trimethylolpropane trimethacrylate.
Composition Film Monomeric Film Polymer _ (weight Temp. Max HOWE Max HOWE
I _ ratio) _ I (no)_ % T (no) (no) % T no Via (2:1) 24 355 43 30 350 41 35 Ebb (1:1) 25 388 52 15 400 42 40 Vg:C (4:1) 25 700 51 33 730 55 52 Although the film derived from pair Via demonstrates suitable optical properties, it's not as stable as other films in which both members of the pair are polymerizable. For example, when this polymeric film was heated at 60 C for one day, it underwent crystallization to give an opaque colorless film.
This invention is not restricted solely to the descriptions and illustrations provided above, but encompasses all modifications envisaged by the following claims.
, ' .
Claims (26)
1. A composition suitable to provide a polymeric film having a fixed optical response, said composition comprising a photopolymerizable monomer having the structure where R1 = H or CH3, A = -R2-, -R3O-, or -R4O-, R2 = an alkylene chain having 3-14 methylene or lower alkyl- substituted methylene groups, R3 = an alkylene chain having from 2-14 methylene or lower alkyl-substituted methylene groups, R4 = an alkylene or lower alkyl-substituted alkylene ether, diether or triether having a total of from 3-14 carbon atoms in the alkylene linkages, provided that the terminal alkylene linkage adjacent the carbonate moiety comprises not less than two carbon atoms, and y = 0 or 1; and a suitable photoinitiator.
2. The composition as set forth in claim 1 hereof wherein said composition comprises a second material which is suitable to permit formation of a film that exhibits cholesteric liquid crystalline properties.
3. The composition as set forth in claim 2 hereof wherein said second material is a compound having the structure of claim 1.
4. The composition as set forth in claim 2 hereof wherein said second material is a photopolymerizable material having a structure which is different from that of claim 1.
5. The composition as set forth in claim 2 hereof wherein said second material is a mesogenic material having a structure which is different from that of claim 1.
6. The composition as set forth in claim 2 hereof wherein said composition comprises a cross-linking agent.
7. The composition as set forth in claim 2 hereof wherein the alkylene of R4 is lower-alkyl substituted.
8. A polymeric film having a fixed optical response, said film being obtained by photopolymerizing a composition comprising a photopolymerizable monomer having the structure where R1 = H or CH3, A = -R2-, -R3O- or -R4O-, R2 = an alkylene chain having from 3-14 methylene or lower alkyl-substituted methylene groups, R3 = an alkylene chain having from 2-14 methylene or lower alkyl-substituted methylene groups, R4 = an alkylene or lower alkyl-substituted alkylene ether, diether or triether having a total of from 3-14 carbon atoms in the alkylene linkages, provided that the terminal alkylene linkage adjacent the carbonate moiety comprises not less than two carbon atoms, and y = 0 or 1; and a suitable photoinitiator.
9. The film as set forth in claim 8 hereof wherein said composition comprises a second material which is suitable to permit formation of a film that exhibits cholesteric liquid crystalline properties.
10. The film as set forth in claim 9 hereof wherein said second material is a compound having the structure of claim 8.
11. The film as set forth in claim 9 hereof wherein said second material is a photo-polymerizable material having a structure which is different from that of claim 8.
12. The film as set forth in claim 9 hereof wherein said second material is a mesogenic material having a structure which is different from that of claim 8.
13. The film as set forth in claim 9 hereof wherein said composition comprises a cross-linking agent.
14. The film as set forth in claim 9 hereof wherein the alkylene of R4 is lower-alkyl substituted.
15. The film as set forth in claim 9 hereof wherein said film is colored.
16. The film as set forth in claim 15 hereof wherein said film comprises multilple colors.
17. The film as set forth in claim 9 hereof wherein said film reflects ultraviolet light.
18. The film as set forth in claim 9 hereof wherein said film reflects infrared light.
19. A process for preparing films comprising polymeric liquid crystalline materials having a fixed optical response, said process comprising the steps of preparing a film comprising a photopoylmerizable monomer having the structure where R1 = H or CH3, A = -R2-, -R3O- or -R4O-, R2 = an alkylene chain having from 3-14 methylene or lower alkyl-substituted methylene groups, R3 = an alkylene chain having from 2-14 methylene or lower alkyl-substituted methylene groups, R4 = an alkylene or lower alkyl-substituted alkylene ether, diether or triether having a total of from 3-14 carbon atoms in the alkylene linkages, provided that the terminal alkylene linkage adjacent the carbonate moiety comprises not less than two carbon atoms, and y = 0 or 1; and a suitable photoinitiator;
aligning said film;
adjusting the temperature of said film to obtain a desired optical response; and photopolymerizing said film.
aligning said film;
adjusting the temperature of said film to obtain a desired optical response; and photopolymerizing said film.
20. The process as set forth in claim 19 hereof wherein said film comprises a second material which is suitable to permit formation of a film that exhibits cholesteric liquid crystalline properties.
21. The process as set forth in claim 20 hereof wherein said second material is a compound having the structure of claim 19.
22. The process as set forth in claim 20 hereof wherein said second material is a photo-polymerizable material having a structure which is different from that of claim 19.
23. The process as set forth in claim 20 hereof wherein said second material is a mesogenic material having a structure which is different from that of claim 19.
24. The process as set forth in claim 20 hereof wherein said composition comprises a cross-linking agent.
25. The process as set forth in claim 20 hereof wherein the alkylene of R4 is lower-alkyl substituted.
26. The process as set forth in claim 20 hereof comprising the additional steps of masking at least a portion of said film from the photopolymerizing radiation, removing said mask upon completion of the photopolymerization, adjusting the temperature of said film such that the unpolymerized regions of said film exhibit a different optical property, and photo polymerizing said film, thereby providing a polymeric film which exhibits multiple optical properties.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US45008982A | 1982-12-15 | 1982-12-15 | |
| US450,089 | 1982-12-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1214592A true CA1214592A (en) | 1986-11-25 |
Family
ID=23786723
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000431937A Expired CA1214592A (en) | 1982-12-15 | 1983-07-06 | Polymeric liquid crystals |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS59109505A (en) |
| BE (1) | BE897871A (en) |
| CA (1) | CA1214592A (en) |
| DE (1) | DE3340954C2 (en) |
| FR (1) | FR2537989B1 (en) |
| GB (1) | GB2132623B (en) |
| LU (1) | LU85102A1 (en) |
| NL (1) | NL186584C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5629055A (en) * | 1994-02-14 | 1997-05-13 | Pulp And Paper Research Institute Of Canada | Solidified liquid crystals of cellulose with optically variable properties |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2572813A1 (en) * | 1984-11-07 | 1986-05-09 | Armstrong World Ind Inc | PROCESS FOR PREPARING POLYMERIC LIQUID COATINGS HAVING MULTIPLE OPTICAL ANSWERS AND COATINGS THUS OBTAINED |
| US4780383A (en) * | 1985-02-27 | 1988-10-25 | Armstrong World Industries, Inc. | Optical storage system having expanded capacity |
| GB2185487B (en) * | 1986-01-16 | 1990-06-06 | Gen Electric Plc | Electro-optical material |
| JPH02167527A (en) * | 1986-05-19 | 1990-06-27 | Seiko Epson Corp | Liquid crystal device |
| US5073294A (en) * | 1990-03-07 | 1991-12-17 | Hercules Incorporated | Process of preparing compositions having multiple oriented mesogens |
| JP2630044B2 (en) * | 1990-07-17 | 1997-07-16 | 凸版印刷株式会社 | Reversible thermosensitive recording medium and manufacturing method thereof |
| JP2630045B2 (en) * | 1990-09-21 | 1997-07-16 | 凸版印刷株式会社 | Reversible thermosensitive recording medium and manufacturing method thereof |
| DE4418075C2 (en) * | 1994-05-24 | 2000-06-29 | Daimler Chrysler Ag | Effect lacquer or effect lacquering, in particular for vehicle bodies, using liquid-crystalline interference pigments |
| DE4441651A1 (en) * | 1994-11-23 | 1996-04-25 | Basf Ag | Polymerisable material for coating and printing substrates |
| DE19520704A1 (en) * | 1995-06-09 | 1996-12-12 | Basf Ag | Polymerizable chiral compounds and their use |
| GB2321717A (en) | 1997-01-31 | 1998-08-05 | Sharp Kk | Cholesteric optical filters |
| DE19745647A1 (en) * | 1997-10-15 | 1999-04-22 | Basf Ag | Heat insulation covering for e.g. insulation and in automobile sector |
| US7879256B2 (en) * | 2006-03-31 | 2011-02-01 | E. I. Du Pont De Nemours And Company | Liquid crystal compositions, polymer networks derived therefrom and process for making the same |
| JP5510483B2 (en) * | 2006-06-29 | 2014-06-04 | Ｊｎｃ株式会社 | Polymerizable liquid crystal composition and use thereof |
| JP5119736B2 (en) * | 2006-06-29 | 2013-01-16 | Ｊｎｃ株式会社 | Polymerizable liquid crystal composition and use thereof |
| JP5262076B2 (en) * | 2007-11-14 | 2013-08-14 | Ｊｎｃ株式会社 | Polymerizable menthol derivative |
| JP2011137850A (en) * | 2009-12-25 | 2011-07-14 | Dainippon Printing Co Ltd | Infrared reflection member |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3409404A (en) * | 1963-11-13 | 1968-11-05 | Westinghouse Electric Corp | Analytical methods and devices employing cholesteric liquid crystalline materials |
| US3594126A (en) * | 1969-04-30 | 1971-07-20 | Westinghouse Electric Corp | Temperature-limit detection |
| CA1255653A (en) * | 1982-12-15 | 1989-06-13 | Paul J. Shannon | Liquid crystalline materials useful to prepare polymeric films |
-
1983
- 1983-07-06 CA CA000431937A patent/CA1214592A/en not_active Expired
- 1983-08-02 JP JP14066683A patent/JPS59109505A/en active Granted
- 1983-09-29 BE BE0/211610A patent/BE897871A/en not_active IP Right Cessation
- 1983-11-11 DE DE19833340954 patent/DE3340954C2/en not_active Expired
- 1983-11-25 LU LU85102A patent/LU85102A1/en unknown
- 1983-12-02 FR FR8319297A patent/FR2537989B1/en not_active Expired
- 1983-12-13 NL NL8304277A patent/NL186584C/en not_active IP Right Cessation
- 1983-12-14 GB GB8333324A patent/GB2132623B/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5629055A (en) * | 1994-02-14 | 1997-05-13 | Pulp And Paper Research Institute Of Canada | Solidified liquid crystals of cellulose with optically variable properties |
Also Published As
| Publication number | Publication date |
|---|---|
| NL186584C (en) | 1991-01-02 |
| DE3340954C2 (en) | 1986-07-17 |
| JPH0224297B2 (en) | 1990-05-29 |
| NL8304277A (en) | 1984-07-02 |
| FR2537989B1 (en) | 1987-06-05 |
| DE3340954A1 (en) | 1984-07-19 |
| LU85102A1 (en) | 1984-04-02 |
| JPS59109505A (en) | 1984-06-25 |
| BE897871A (en) | 1984-01-16 |
| NL186584B (en) | 1991-01-02 |
| GB2132623A (en) | 1984-07-11 |
| GB2132623B (en) | 1987-06-10 |
| FR2537989A1 (en) | 1984-06-22 |
| GB8333324D0 (en) | 1984-01-18 |
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