Liquid crystal phase-forming polymers.

0001The invention relates to liquid-crystalline phase-forming polymers, their production and use and the monomers on which these polymers are based.

0002Low-molecular nematic, smectic, cholesteric or discotic liquid-crystalline systems are known, the characteristic phase properties of which have led to interesting and versatile applications in technology, electro-optics and research. A major disadvantage of the low molecular weight liquid crystal systems is that they completely change their structural parameters during the transition from the liquid crystalline phase to the solid phase (C. Destrade, NH Tinh, H. Gasparoux, J. Malthete, AM Levelut; Disc-Like Mesogens: A Classification in: Mol. Cryst. Liq. Cryst. 71, 111 ff. (1981)).

0003For some time now, polymers with liquid-crystalline properties have been known in which the rigid anisotropic molecular sections leading to the mesophase are arranged in the main chain. The molecular sections leading to the mesophase are connected to one another via flexible alkylene chains (spacers). The latter allow orientation and phase transformation at temperatures in the range of -30 to 200 ° C, made possible by the correspondingly low glass softening temperatures of the polymer.

0004Furthermore, polymers are known in which the rigid anisotropic molecular sections leading to the mesophase are bound as side chains to a polymer chain.

0005So far, only polymers are known which form nematic, smectic or cholesteric phases (EP-A 7574).

0006The object of the present invention was to develop polymers which form discotic phases.

0007It has been found that discotic phase-forming liquid-crystalline polymers are present when the polymer contains, as mesogenic groups, chemically bonded groups which generate discotic phases.

0008These new polymers show new properties or combinations of properties which the known liquid-crystalline phase-forming polymers do not have.

0009An effect not known for other liquid-crystalline polymers is the self-reinforcing birefringence induced by shear. If a sample of the polymers according to the invention is irradiated with polarized light between two planar transparent plates, the sample appears dark. The sample becomes translucent through brief shear. After the shear is finished, the light transmittance increases 2 to 5 times.

0010The new polymers contain chemically bound discotic phase-generating groups as mesogenic groups. The latter can either be bonded via spacers in the chain and thus be part of the main polymer chain or bonded to the polymer chain via connecting groups (spacers) and thus be part of a side chain.

0011Groups which form discotic phases - hereinafter also referred to as discotic groups or mesogens - are, for example, compounds of the following general formulas:<chemistry id="chem0001" num="0001"><img file="EP0140133A2_D0001.tif" /></chemistry><chemistry id="chem0002" num="0002"><img file="EP0140133A2_D0002.tif" /></chemistry>

0012Depending on whether they are incorporated in the polymer chain as chain links or are bound to the polymer chain as side chains, the discotic groups are bound via two of the radicals R, or one of the radicals R via two or a spacer.

0013Accordingly, one or two R in formulas (I) to (IV) represent a radical of the general formula<chemistry id="chem0003" num="0003"><img file="EP0140133A2_D0003.tif" /></chemistry>and the remaining R for radicals of the general formula<chemistry id="chem0004" num="0004"><img file="EP0140133A2_D0004.tif" /></chemistry>

0014Stand in the formulas (V) and (Va)<chemistry id="chem0005" num="0005"><img file="EP0140133A2_D0005.tif" /></chemistry><ul id="ul0001" list-style="none"><li>n for 0, 1, 2 or 3,</li><li>Z for a chemical bond, -0-, -S-,<chemistry id="chem0006" num="0006"><img file="EP0140133A2_D0006.tif" /></chemistry>-SO₂-, <chemistry id="chem0007" num="0007"><img file="EP0140133A2_D0007.tif" /></chemistry><chemistry id="chem0008" num="0008"><img file="EP0140133A2_D0008.tif" /></chemistry>where Z can be the same or different,</li><li>R¹ for hydrogen or C₁- to C₄-Alkyl,</li><li>A for C₄- to C25-alkyl, C₄- to C₂₀-Alkylphenyl or C₄- to C₂₀-Alkoxyphenyl and</li><li>V for a spacer, preferably for a C₂- to C₂₅-Alkylene</li></ul>and wherein the alkyl chain in A and / or the alkylene chain in V optionally by<ul id="ul0002" list-style="none"><li>-0-, -S- and / or<chemistry id="chem0009" num="0009"><img file="EP0140133A2_D0009.tif" /></chemistry>are interrupted and the distance between two heteroatoms is at least 2 carbon atoms.</li></ul>

0015i A and V are preferably attached to the polymer chain or in the polymer chain as well as to the discotic groups via a chemical bond or via -<chemistry id="chem0010" num="0010"><img file="EP0140133A2_D0010.tif" /></chemistry><chemistry id="chem0011" num="0011"><img file="EP0140133A2_D0011.tif" /></chemistry>bound.

0016Suitable spacers are, in particular, alkylene groups with 2 to 25 carbon atoms, which are linear or branched and whose chain is defined by -0-, -S- or <chemistry id="chem0012" num="0012"><img file="EP0140133A2_D0012.tif" /></chemistry> can be interrupted.

0017The following are examples of spacers:<chemistry id="chem0013" num="0013"><img file="EP0140133A2_D0013.tif" /></chemistry><chemistry id="chem0014" num="0014"><img file="EP0140133A2_D0014.tif" /></chemistry><chemistry id="chem0015" num="0015"><img file="EP0140133A2_D0015.tif" /></chemistry><chemistry id="chem0016" num="0016"><img file="EP0140133A2_D0016.tif" /></chemistry><chemistry id="chem0017" num="0017"><img file="EP0140133A2_D0017.tif" /></chemistry>

0018The alkylene radicals Y are -CH₂-, - (CH₂)̵₂, (̵CH₂)̵₃ and<chemistry id="chem0018" num="0018"><img file="EP0140133A2_D0018.tif" /></chemistry>to call.

0019R¹ stands for C₁- to C₄-Alkyl such as methyl or ethyl. Preferably R is¹ Methyl and especially hydrogen.

0020For A, for example, the following should be mentioned in detail:<ul id="ul0003" list-style="none"><li>as C₄- to C₂₅-Alkyl: n-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl; Heneicosyl, docosyl, tetracosyl and pentacosyl;</li><li>as C₄- to C₂₀-Alkylphenyl: 4-butylphenyl, 4-pentylphenyl, 4-hexylphenyl, 4-octylphenyl, 4- (1 ', 1', 3 ', 3'-tetramethylbutyl) -phenyl, 4-nonylphenyl, 4-decylphenyl, 4-undecylphenyl , 4-dodecylphenyl, 4-tridecylphenyl, 4-tetradecylphenyl, 4-hexadecylphenyl, 4-octaphenyldecyl and 4-eicosylphenyl; and</li><li>as C₄- to C₂₀-Alkoxyphenyl; 4-butoxyphenyl, 4-pentoxyphenyl, 4-hexoxyphenyl, 4-octoxyphenyl, 4- (2'-ethylhexoxy) phenyl, 4-nonoxyphenyl, 4-decoxyphenyl, 4-undecoxyphenyl, 4-dodecoxyphenyl, 4-tridecoxyphenyl, 4-tetradecoxyphenyl , 4-pentadecoxyphenyl, 4-hexadecoxyphenyl, 4-heptadecoxyphenyl, 4-octadecoxyphenyl, 4-nonodecoxyphenyl and 4-eicosyloxyphenyl.</li><li>For V are C₄- to C₂₅Alkylene particularly preferred and to be mentioned in particular as preferred: 1,4-butylene and 1,3, pentylene-1,5, hexylene-1,6, octylene-1,8, undecylene-1,11, deeylene-1 , 10, dodecylene-1.12, tetradecylene-1.14, hexadecylene-1.16, octadecylene-1.18, - (CH₂)̵₂₀, - (CH₂)̵₂₁, - (CH₂)̵₂₂, (̵CH₂)̵₂₄ and - (CH₂)̵₂₅.</li><li>For A is C₄- to C₁₂-Alkyl preferred. Y preferably stands for<chemistry id="chem0019" num="0019"><img file="EP0140133A2_D0019.tif" /></chemistry>or - (CH₂)̵_n with n = 0, 1 or 2. Z is -0-, -S-, -SO₂-, <chemistry id="chem0020" num="0020"><img file="EP0140133A2_D0020.tif" /></chemistry>particularly preferred.</li></ul>

0021The discotic group is bonded to the polymer chain via a spacer, preferably via the groups mentioned as particularly preferred for Z, or also via -YZ-, where Y represents - (CH₂)̵_n with n = 1 or 2.

0022Of the discotic groups, those of the formulas (I), (II) and (IV) are preferred. In these formulas, R is preferably a remainder of the formulas<chemistry id="chem0021" num="0021"><img file="EP0140133A2_D0021.tif" /></chemistry>or.<chemistry id="chem0022" num="0022"><img file="EP0140133A2_D0022.tif" /></chemistry>in which<ul id="ul0004" list-style="none"><li>Y 'for a chemical bond, <chemistry id="chem0023" num="0023"><img file="EP0140133A2_D0023.tif" /></chemistry>or -CH₂- and</li><li>Z 'for a chemical bond or for -O-, -S-, -S0₂-, -NH-,<chemistry id="chem0024" num="0024"><img file="EP0140133A2_D0024.tif" /></chemistry><chemistry id="chem0025" num="0025"><img file="EP0140133A2_D0025.tif" /></chemistry>and A and V have the meaning given above. A is preferably C.₄- to C₁₂-Alkyl and V for C₄- to C₂₅-Alkplen.</li></ul>

0023In the discotic groups of formula (I), Y 'is preferably -CH₂-, <chemistry id="chem0026" num="0026"><img file="EP0140133A2_D0026.tif" /></chemistry>or a chemical bond and Z 'a chemical bond or -O-, -S-, -NH-, -SO₂-, <chemistry id="chem0027" num="0027"><img file="EP0140133A2_D0027.tif" /></chemistry>

0024In the discotic groups (II), Y 'is preferably a chemical bond and Z' is a chemical bond or -0-, -S-,<chemistry id="chem0028" num="0028"><img file="EP0140133A2_D0028.tif" /></chemistry>or<chemistry id="chem0029" num="0029"><img file="EP0140133A2_D0029.tif" /></chemistry>

0025A and V have the meaning given.

0026The polymers which contain groups which form discotic phases chemically bonded can be prepared by processes which are known per se and are customary in polymer chemistry. A distinction must be made between the polymers in which the group providing the discotic phases is bound as a chain link in the chain and those in which the discotic group is bound as a side chain or to a side chain.

0027Polymers in which the discotic groups are linked as chain links in the polymer chain can, for example, by polycondensation of compounds which contain two terminal carboxyl groups or their functional derivatives in the molecule, with components which have two terminal reactive groups which react with the carboxyl group or their functional derivatives, such as Containing hydroxyl, amino or mercapto in the molecule. The discotic groups can carry carboxyl groups or functional derivatives of the carboxyl groups as well as groups reacting with the carboxyl groups. Polyesters and polyamides, in particular polyesters, are preferred as polymers.

0028Another process for the production of polymers in which the mesogenic groups are links in the polymer chain consists in the polyaddition of diisocyanates with terminal isocyanate groups with compounds which carry substituents which react with isocyanate. In this case too, the discotic phase-providing compound can carry both the isocyanate residues and the residues reacting with the isocyanate.

0029The radicals which react with the isocyanate are preferably -SH and -NH₂ and especially -OH.

0030The reaction takes place in a manner known per se under customary conditions. The reaction temperatures are around 50 ° C. Ketones such as methyl ethyl ketone or acetone or ethers such as tetrahydrofuran are suitable as solvents. Common catalysts include dibutyltin laurate and 1,4-diaza - bicyclo- [2,2,2] octane. These are generally used in concentrations of 0.1 to 1% by weight, based on the mixture as a whole.

0031Polymers that contain mesogens in the side chain or as a side chain can be produced, for example, by polymer-analogous reactions. The distance from the main chain to the mesogen should be at least 4 chain links.

0032For example, in polymeric compounds which contain links of the formula (VII) in the chain,<chemistry id="chem0030" num="0030"><img file="EP0140133A2_D0030.tif" /></chemistry>where T is an exchangeable radical such as hydroxy, chlorine, low molecular weight alkoxy and R² Hydrogen, methyl, chlorine or bromine are introduced by esterification, transesterification or acylation mesogens with an R-terminated hydroxyl, mercapto or amino group.

0033The methods are known per se (CM Paleos et al .; J. Polym. Sci. Polym. Chem. Ed., 19, 1427 (1981)).

0034T can also be exchanged with a reactive group of a spacer bound to a discotic group.

0035In the case of discotic groups which carry a terminal carboxyl group or their functional derivatives, the polymer must contain amino, mercapto or hydroxyl groups. Such polymers can be obtained, for example, by copolymerizing (meth) acrylic acid half-esters of 1, -diols with other comonomers.

0036The polymer-analogous reaction then takes place in a manner known per se.

0037A further possibility of binding discotic groups to the polymer chain consists in the reaction of discotic groups bearing an isocyanate radical with polymers which have substituents which react with isocyanate, for example copolymers bearing hydroxyl groups mentioned above.

0038The isocyanate radical can be added to the discotic group, for example, by reacting a discotic phase-forming compound which has an R which is a substituent which reacts with isocyanate, such as -OH, -SH or -NH₂ carries, with a diisocyanate in a molar ratio of 1: 1.

0039The reaction of the discotic group bearing an isocyanate radical with the reactive substituent-carrying polymer is carried out according to methods known per se.

0040Conversely, it is also possible to introduce isocyanate residues into polymers and to implement the isocyanate residues with discotic groups which have a terminal substituent which reacts with isocyanate on an R.

0041Furthermore, polymers which form liquid-crystalline phases can be formed by condensation of discotic groups which carry hydroxyl, amino, thio or carboxyl groups on two spacers with bifunctional compounds which react with the groups on the spacers to form a chemical bond to form polymers , are produced, for example by polycondensation of discotic groups which carry two radicals -YZVZH and ZH for, for example, -0H, -NR₂ or -SH, with 1,10-alkanedicarboxylic acids having 6 to 20 carbon atoms, for example adipic acid, 1,6-hexanedicarboxylic acid, 1.8-octanedicarboxylic acid, 1.1-decanedicarboxylic acid in a ratio of 0.9: 1 to 1: 0.9, preferably 1: 1 mol.

0042Polymers which carry mesogens bonded in the side chain or bound to the side chain can also be obtained by polymerizing ethylenically unsaturated compounds of the formula<chemistry id="chem0031" num="0031"><img file="EP0140133A2_D0031.tif" /></chemistry>optionally with other olefinically unsaturated compounds which are copolymerizable with (VIII). Accordingly, the polymers thus produced consist of units of the formula<chemistry id="chem0032" num="0032"><img file="EP0140133A2_D0032.tif" /></chemistry>or contain units of the formula (VIIIa) in the chain.

0043In the formulas (VIII) and (VIIIa), W represents a discotic group of the formulas (I), (II), (III) bonded to the carbon atom of the carbonyl radical via -Y'-Z'-V-Z'- or (IV), wherein Y 'is a chemical bond, Z' -0-, -S- or <chemistry id="chem0033" num="0033"><img file="EP0140133A2_D0033.tif" /></chemistry>means and V has the meaning given above.

0044Suitable comonomers for the copolymerization of (VIII) or as comonomers for the preparation of the polymers required for the polymer-analogous reactions are those monomers which deliver homo- or copolymers with glass transition temperatures of &lt;100 ° C.

0045The degree of polymerization is generally between 5 and 500, preferably between ≥ 10 and 100.

0046The following are particularly suitable as comonomers:<ul id="ul0005" list-style="none"><li>C._l- to C₂₀-, preferably C₄- to C₈Alkyl esters of acrylic acid and / or methacrylic acid, mixtures of these esters and mixtures of the esters mentioned with acrylonitrile, methacrylonitrile, styrene, 4-methylstyrene, acrylamide and / or methaerylamide.</li></ul>

0047In addition to those specified above, the following may in particular be considered as comonomers:<ul id="ul0006" list-style="none"><li>Methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, nonylacrylate, decyl acrylate, dodecyl acrylate, hexadecyl acrylate, octadecyl acrylate and the corresponding methacrylate.</li></ul>

0048The above-mentioned acrylates and methacrylates of alkanols having 4 to 8 carbon atoms are preferred.

0049The polymers are prepared by known processes, preferably by radical polymerization.

0050Polymers which contain discotic groups as side chains or bound to side chains can also be obtained by adding polarizable, reactive hydrogen-bearing radicals to olefinic double bonds.

0051For example, polyorgano-hydrogen siloxanes can be reacted with mesogens containing a terminal vinyl group, if appropriate in solvents in the presence of catalysts, in particular hexachloroplatinic acid, which accelerate the addition of hydrogen bonded to Si to aliphatic multiple bonds.

0052These reactions are carried out in a manner known per se (H. Ringsdorf, A. Schneller; Brit. Polym. Journal 13, 43 (1981); H. Ringsdorf, A. Schneller Makromol. Chem., Rapid Comm. Vol. 3, 557 ( 1982)).

0053The polymers according to the invention, which contain groups which form discotic phases as chemically bound mesogenic groups, can be used in very different ways. The application results on the one hand from the liquid-crystalline properties and on the other hand from the specific properties of the polymers. The unusually high anisotropy of the refractive indices, in contrast to organic materials, opens up possible applications as an optical coating material and as an optical material for components with integrated optics. Because the polymers according to the invention are processed as a viscous liquid above the glass transition temperature and the position of the optical axis can be determined by electrical or magnetic fields, and because the shapes and structures of the orientation, which can be designed as information carriers, are cooled to temperatures can be fixed below the glass temperature, their use in or as storage elements or in electro-optical display elements is possible.

0054On the other hand, the translucency that changes due to shear can be used, for example, for the optical measurement of elongation processes in mechanical engineering, in structural engineering and in mining (elongation sensors).

0055Colored discotic polymers are preferably used in or as optical storage elements or electro-optical displays. The latter are obtained by adding pleochroic dyes which dissolve in the discotic polymers and which are based on the mesogenic groups, or by incorporating pleochroic dyes into the main chain or into the side chain of the polymers according to the invention (DE-OS 32 11 400).

0056Electrically conductive or photoconductive discotic polymers can be produced by incorporating mesogenic residues with electron donor or electron acceptor properties in polymers which contain chemically bonded groups which form mesogenic discotic phases.

0057The polymers according to the invention and their preparation are to be illustrated in addition by the following examples.

example 1

00587 mg of a methyl) hydrogen polysiloxane of the formula<chemistry id="chem0034" num="0034"><img file="EP0140133A2_D0034.tif" /></chemistry>and 99 mg of 2-uadecenoxy-3,6,7,10,11-penta-n-pentoxy-triphenylene, prepared according to Example A.2) were dissolved in 2 ml of toluene and 100 ppm of hexachloroplatinic acid, based on the solution, were added. The mixture was kept at 80 ° C for 2 days.

0059The organopolysiloxane was purified by preparative gel permeation chromatography in tetrahydrofuran and dried in vacuo. The polymer contains an average of. Polymer chain 35 groups of compound (A.2). The polymer had a glass transition temperature of approx. -29 ° C. The transition temperature discotic / isotropic is + 39 ° C, the conversion heat was determined to be 13 J / g.

Example 2

0060According to the information in Example 1, 17 mg of a copolysiloxane of the formula<chemistry id="chem0035" num="0035"><img file="EP0140133A2_D0035.tif" /></chemistry>in which the Si (CH₃)₂0- and SiHCH₃O groups are randomly distributed and n is 35 on average, with 126 mg of 2-undecenoxy-3,6,7,10, 11-penta-n-pentoxy-triphenylene, prepared according to Example A.2). The polymer obtained contains on average 35 groups of compound A.2) bound to the polymer chain.

0061The polymer obtained had a discotic phase which transitioned to the isotropic phase at 36 ° C. The enthalpy of conversion is determined to be 11.7 J / g. The glass temperature was -29 ° C.

Example A

0062<chemistry id="chem0036" num="0036"><img file="EP0140133A2_D0036.tif" /></chemistry>

A.1) 2-Monoacetoxy-3,6,7,10,11-penta-n-pentoxytriphenylene

00634th g (6.9 mmol) 2,3,6,7,10,11-hexyacetoxy-triphenylene XI (manufactured according to OC Musgrave, CJ Webster; J. Chem. Soc. C: 1971, p. 1397), 8.1 g (58.5 mmol) of anhydrous, finely powdered potassium carbonate and 21.2 g (140 mmol) of n-pentyl bromide were stirred in 80 ml of acetophenone under a nitrogen atmosphere at 116 ° C. for 16.5 h. The cooled reaction mixture was suctioned off through a G 3 frit and the filter residue was extracted several times warm with a total of 250 ml of ether until a sample of the residue was completely soluble in water. The filtrate and the ether extract were combined and three times with 100 ml each with CO₂-saturated water washed. After drying over anhydrous sodium sulfate, the ether was distilled off and acetophenone and excess pentyl bromide were distilled off at temperatures below 50 ° C. in an oil pump vacuum.

0064The slowly crystallizing residue was taken up in 20 ml of acetic anhydride in order to acetylate any free OH groups present. The excess acetic anhydride was removed in vacuo. Residue: 5 g of crude product containing 2,3,6,7,10,11-hexapentoxytriphenylene, 2-monoacetoxy-3,6,7,10,11 -pentapentoxytriphenylene and diacetoxy-tetrapentoxytriphenylene.

0065The crude product was separated by column chromatography on silica gel (500 g) with methylene chloride / petroleum ether - 3: 2 volume in fractions, the middle of which contain the desired 2-acetoxy-3,6,7,10,11-pentapentoxy compound.

0066The last fractions contain the diacetoxy compounds.

0067The products obtained from the concentrated fractions were further purified by recrystallization from ethanol / diethyl ether or methanol.

0068The 2-monoacetoxy-3,6,7,10,11-penta-n-pentoxytriphenylene has a clearing point of 161 ° C. It does not crystallize above -50 ° C.

A.2) 2- (Undecen-10'-oxy) -3,6,7,10,11-penta-n-pentoxytriphenylene

00692-Acetoxy-3,6,7,10,11-penta-n-pentoxytriphenylene from A.1 is in the presence of anhydrous finely powdered R₂CO₃ reacted with 1-bromo-undecylene-10 in acetophenone for 7 days at room temperature.

0070The processing and cleaning was carried out analogously to the information under A.1).

A.3) 2,6-diacetoxy-3,7,10,11-cetra-n-pentoxytriphenylene

0071was isolated in pure form from the first fractions of A.1) containing diacetoxy-tetrapentoxytriphenylene. After evaporating the fractions, the residue was recrystallized from methanol.

Example 3

Discotic polyester through polycondensation in the melt

0072<chemistry id="chem0037" num="0037"><img file="EP0140133A2_D0037.tif" /></chemistry>R = - (CH₂)₄CH₃ 599.7 mg (= 0.87 mmol) of 2,6-diacetoxy-3,7,10,11-tetra-n-pentoxy-triphenylene (which was recrystallized from methanol) is mixed with 200.3 mg (= 0.1 87 mmol) decane-1,10-dicarboxylic acid (recrystallized from 20% ethanol and then recrystallized from ethanol: hexane = 1: 1 vol.) Mixed. 1.5 mg (= 1 mol.%) Of p-toluenesulfonic acid are added as catalyst. The mixture is heated to 130 ° C. under a protective gas atmosphere, a melt being formed. This temperature is held for 2 hours. The mixture is then distilled off for 1 hour at 200 mbar acetic acid and the pressure is reduced to ~ 20 mbar in accordance with the evolution of gas bubbles. Duration 2 hours.

0073It is then heated in vacuo to an oil pump (pressure: 0.5 to 0.05 mbar), the temperature having to be increased by 10 ° C. in order to obtain an isotropic (clear) melt in each case. Finally, the melt is held at T = 185 ° C. for 3 hours at a pressure of &lt;0.01 mbar. After cooling, the melt cake obtained is dissolved in 7 ml of THF and carefully precipitated in 120 ml of n-hexane. The precipitate is centrifuged off, digested with hexane and centrifuged, taken up again in 5 ml of THF and precipitated again in 70 ml of hexane. The dried polymer no longer contains any residues of the starting substance (thin layer chromatography in CH₂Cl₂: Rf - 0).

0074Yield: 410 mg = 59% of theory

0075Phases according to DSC and polarization microscopy:<ul id="ul0007" list-style="none"><li>g 40 ° CD 194 ° C i</li><li>D = discostatic columnar phase</li><li>i = isotropic phase.</li></ul>

0076Enthalpy at transition D to i: 15 J / g.

Example 4

007720 mg of the polymer obtained according to Example 1 are dissolved in 1 ml of methylene chloride and treated with 1 mg of tetradecyloxy copper phthalocyanine of the formula (XIII)<chemistry id="chem0038" num="0038"><img file="EP0140133A2_D0038.tif" /></chemistry>

0078(T = -C₁₀H₂₁) in the form of a 5 Xigen solution in tetrahydrofuran. The solvents are allowed to evaporate at room temperature and are then kept for 12 hours at room temperature at a pressure of 1 mbar. No change in the mesophase behavior can be observed on the colored polymer.

Example 5

0079The procedure is as in Example 4, but the compound XIII with ^{T -} C12H25 used.

0080A blue-colored polymer is obtained which corresponds in phase behavior to the polymer of Example 1.