EP0958316A1

EP0958316A1 - Chirally nematic polyesters

Info

Publication number: EP0958316A1
Application number: EP98909394A
Authority: EP
Inventors: Hans R. Kricheldorf; Thorsten Krawinkel; Andreas Gerken; Peter Schuhmacher
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1997-02-06
Filing date: 1998-02-05
Publication date: 1999-11-24
Also published as: CN1252078A; KR20000070763A; US6291629B1; DE19704506A1; WO1998034974A1; JP2001511205A

Abstract

The invention relates to liquid crystal chirally nematic polyesters with flexible chains, comprising isosorbide, isomannide, and/or isoidide units. The polyesters are not crystalline and form stable Grandjean textures which freeze on cooling below glass transition temperature. They are thus particularly suitable for use as surface coating materials

Description

Chiral nematic polyester

description

The invention relates to liquid-crystalline chiral nematic polyesters.

When heating anisotropic substances, liquid-crystalline phases, so-called mesophases, can occur. The individual phases differ in the spatial arrangement of the molecular centers on the one hand and in the molecular arrangement with respect to the longitudinal axes on the other (G. Gray, P A. Winsor, Liquid Crystals and Plastic Crystals, Ellis Horwood Limited, Chichester 1974). The nematic liquid-crystalline phase is characterized by the parallel orientation of the longitudinal axes of the molecules (one-dimensional order). Provided that the molecules that make up the nematic phase are chiral, a so-called chiral nematic (cholesteric) phase is formed in which the longitudinal axes of the molecules form a helical superstructure that is perpendicular to it (H. Baessler, Solid State Problems XI, 1971). The chiral part of the molecule can either be present in the liquid-crystalline molecule itself or be added to the nematic phase as a dopant, the chiral nematic phase being induced. This phenomenon was first investigated on cholesterol derivatives (e.g. H. Baessler, M. M. Labes, J. Chem. Phys. 52, 631 (1970).

The chiral nematic phase has special optical properties: high optical rotation and a pronounced circular dichroism, which is created by selective reflection of circularly polarized light within the chiral nematic layer. If the pitch corresponds to the helical superstructure of the wavelength of visible light, a so-called grandjean texture is formed. The colors, which appear different depending on the viewing angle, depend on the pitch of the helical superstructure, which in turn depends on the twisting relationship of the chiral component. In particular, the pitch and thus the wavelength range of the selectively reflected light of a chiral nematic layer can be varied by changing the concentration of a chiral dopant. Such chiral nematic systems offer interesting possibilities for practical use. By incorporating chiral parts of the molecule into mesogenic acrylic acid esters and orientation in the chiral nematic phase, for example after photocrosslinking, a stable, colored network can be produced, but the concentration of the chiral component can then no longer be changed (G. Galli, M. Laus, A. Angelon, Makromol. Chemie 187, 2289 (1986)). By adding non-crosslinkable chiral compounds to nematic acrylic acid esters, a colored polymer can be produced by photocrosslinking which still contains high proportions of soluble components (I. Heyndricks, DJ Broer, Mol. Cryst. Liq. Cryst. 203, 113 (1991)) . Furthermore, by statistical hydrosilylation of mixtures of cholesterol derivatives and acrylate-containing mesogens with defined cyclic siloxanes and subsequent photopolymerization, a chiral nematic network can be obtained in which the chiral component can have a share of up to 50% in the material used; however, these polymers still contain significant amounts of soluble fractions (Kreuzer University of Applied Sciences, R. Mauerer, Ch. Müller-Rees, J. Stohrer, Lecture No. 7, 22nd Working Conference on Liquid Crystals, Freeburg, 1993).

DE-A-35 35 547 describes a process in which a mixture of cholesterol-containing monoacrylates can be processed to chiral nematic layers by means of photocrosslinking. However, the total proportion of the chiral component in the mixture is approximately 94%. As a pure side chain polymer, such a material is not mechanically very stable, but an increase in stability can be achieved by highly crosslinking diluents.

Numerous chiral nematic polyesters in which the mesogenic structures are built into the main chain are also known, for example from S. Vilasagar, A. Blumstein, Mol. Cryst. Liq. Cryst. (1980), 56 (8), 263-9; A. Blumstein, S. Vilasagar, S. Ponratha, SB Clough, RB Blumstein, G. Maret, J. Polym. Be . , Polym. Phys. Ed. (1982), 20 (5), 877-92; E. Chiellini, G. Galli, C. Manganga, N. Spassky, Polym. Bull (1983), 9 (6-7), 336-43); HJ Park, JI Jin, RW Leng, Polymer (1985), 26 (9), 1301-6; JI Jin, EJ Choi, KY Lee, Polym. J. (1986), 18 (1), 99.101; JI Jin, SC Lee, SD Chi, JH Chang; Pollimo (1986), 10 (4), 382-8; JI Jin, EJ Choi, BW Jo, Pollijno (1986), 10 (6), 635-40; JMG Cowie, HH Wu, Makromol. Chem. (1988), 189 (7), 1511-16; VV Zuev, IG Denisov, SS Skorokhodov, Vyso / cojτ.o2. Soedin. , Ser. A (1989, 31 (5), 1056-61; AS Angeloni, D. Caretti, C. Carlini, E. Chiellini, G. Galli, A. Altomare, R. Solaro, M. Laus, Liq. Cryst. (1986), 4 (5), 513-27; K. Fujishiro, RW Lenz, Macromolecules (1992), 25 (1), 88-95; K. Fujishiro, RW Lenz, Macromolecules (1992), 25 (1) , 81-7; VV Zuev, IG Denisov, SS Skorokhodov, Vysokomol. Soedin., Ser. B (1992), 34 (3), 47-54); VV Zuev, IG Denisov, SS Skorokhodov Vysoko ol. Soedin. , Ser. B (1989), 31 (2), 130-2.

These polyesters generally show narrow areas of existence of the chiral nematic phase and contain predominantly open-chain chiral components which have a low twistability, so that relatively large proportions of these components are necessary in order to achieve a color impression. This makes the selection of the remaining polyester components e.g. limited in their mechanical properties.

DE-A-19504913.6 describes chiral nematic polyesters with chiral diol components with a strong twisting action, in particular dianhydro sugars, and broad liquid-crystalline phase regions.

EP-A-682 092 describes paints based on chiral nematic polymers. Examples which are mentioned are polyesters which have been prepared by polycondensation of dicarboxylic acids and diols.

DE-A-19631658 describes chiral nematic polycarbonates which have been prepared by various types of polycondensation of diols with phosgene or diphosgene.

DE-A-44 41 651 discloses a method for the surface coating of substrates with a coating agent which contains at least one polymerizable low molecular weight liquid-crystalline compound. The use of, in particular, photochemically polymerizable, low molecular weight liquid-crystalline compounds (oligoesters) in printing inks, inks and coating systems is also described.

WO-A-96 02 597 also describes a process for coating or printing substances with a coating or printing agent which contains a chiral or achiral liquid-crystalline monomer and a non-liquid-crystalline chiral compound. The liquid-crystalline monomers are preferably photochemically polymerizable bisacrylates.

WO-A-95 29 962 describes aqueous coating compositions for the production of coatings whose color impression depends on the viewing angle and which contain platelet-shaped pigments from oriented, three-dimensionally crosslinked substances of liquid-crystalline structure with a chiral phase. As a particularly preferred sub- Three-dimensionally crosslinkable polyorganosiloxanes are described.

WO-A-95 29 961 discloses coating compositions with a color impression depending on the viewing angle and their use in basecoats for multi-layer coatings. The compositions contain platelet-shaped pigments with a color that is dependent on the viewing angle and consist of oriented, three-dimensionally crosslinked substances of liquid-crystalline structure with a chiral phase. Three-dimensionally crosslinkable polyorganosiloxanes are described as preferred substances.

DE-A-44 18 076 describes an effect varnish or an effect varnish using liquid-crystalline interference pigments. The interference pigments consist of esterified cellulose ethers, in particular of acylated hydroxypropyl cellulose.

EP-A-724 005 discloses a pigment with a color that is dependent on the viewing angle, its production and use in a lacquer. The pigment is obtained by three-dimensional crosslinking of oriented substances of liquid-crystalline structure with a chiral phase. Preferred substances are three-dimensionally crosslinkable polyorganosiloxanes. In order to make the pigment colourfast compared to elevated temperatures, it is proposed to carry out the crosslinking in the presence of at least one further, color-neutral compound which contains at least two crosslinkable double bonds. Acrylates, polyurethanes, epoxies, siloxanes, polyesters and alkyd resins are mentioned as preferred color-neutral compounds.

EP-A-0686 674 and the priority application on which it is based DE-A-44 16 191 describe interference pigments from molecules fixed in a cholesteric arrangement and their use. The pigments described have a platelet-like structure and a thickness of 1 μm to 20 μm. They contain oriented cross-linked substances of liquid crystalline structure with a chiral phase (preferably polyorganosiloxanes).

EP-A-0601 483 and the priority application on which it is based DE-A-42 40 743 describe pigments with a color that is dependent on the viewing angle, their production and use. The pigments described consist of oriented three-dimensionally crosslinked substances of liquid-crystalline structure with a chiral phase (preferably polyorganosiloxanes) and, if appropriate, further dyes and pigments. Any other dyes and pigments present do not serve as carriers for the oriented three-dimensionally cross-linked liquid-crystalline substances with a chiral phase.

One of the main problems in providing chiral nematic polyester is fixing the Grandjean texture. Various methods for fixing Grandjean textures by crosslinking via σ bonds have recently been published (HR Kricheldorf, N. Probst, M. Gurau, M. Berghahn, Macromolecules 28, 6565 (1995) J. Stumpe, A. Ziegler, M Berghahn, HR Kricheldorf; Macromolecules (1995) 28, 5306; HR Kricheldorf, N. Probst; High Perform. Polym. (1995) 7, 471-480). These methods include the photocrosslinking of UV-sensitive chiral nematic polymers. However, all types of networking have two disadvantages in common. First, the crosslinking process changes the chemical structure of the polymers and, as a result, often changes the supermolecular order that causes the formation of the Grandjean texture. Secondly, the polymers to be crosslinked have to undergo an additional, technologically complex curing step.

Another problem with the provision of chiral nematic polyesters is the fact that most of the liquid crystalline polymers described in the literature and all commercially available liquid crystalline polymers are semi-crystalline materials. However, semi-crystalline materials are unsuitable for many areas of application because the light scattering from the crystallites greatly reduces the brightness and brilliance of the colors.

From H.R. Kricheldorf, N. Probst; Macromol. Rapid. Commun. (1995) 16, 231 and N. Probst, H.R. Kricheldorf; High perform. Polym.

(1995) 7, 461 chiral nematic copoly (ester imides) with a low tendency to crystallize (<20%) are known, but they usually only develop unstable Grandjean textures above 300 ° C. These polymers contain isosorbide or isomannide as the chiral diol component.

Surprisingly, it has now been found that polyesters which comprise diol or dicarboxylic acid units which contain flexibilizing alkylene groups and which comprise isosorbide, isomannide or isoidide units and the polyester chain form stable Grandjean textures without developing a higher tendency to crystallize. They can be fixed without networking without the disadvantages described above and can be produced simply and inexpensively. The present invention therefore relates to chiral nematic polyesters with flexible chains which comprise isosorbide, isomannide and / or isoidide units, preferably isosorbide units, and which contain at least one unit which is selected from (and derived from) to make the chains more flexible.

(a) aliphatic dicarboxylic acids,

(b) aromatic dicarboxylic acids with a flexible spacer,

(c) α, ω-alkanediols,

(d) Diphenols with a flexible spacer and 0 (e) condensation products of a polyalkylene terephthalate or polyalkylene naphthalate with an acylated diphenol and an acylated isosorbide.

The polyesters according to the invention are not crystalline and form 5 stable Grand Jeans textures which can be frozen when they cool below the glass transition temperature. Despite the flexibility, the glass transition temperatures of the polyesters are above 80 ° C., preferably above 90 ° C., in particular above 100 ° C. 0

The polyesters according to the invention are preferably composed of dicarboxylic acids and diols.

The polyesters according to the invention preferably contain, as units (a), those of the formula

—OC— (CH ₂ ) _n —CO—.

where n is a number in the range from 3 to 15, in particular 4 to 30 12 and particularly preferably adipic acid;

as units (b) preferably those of the formula

in which

A represents (CH ₂ ) _n , 0 (CH ₂ ) _n O or (CH ₂ ) _o -0- (CH ₂ ) _p , n is particularly preferably a number in the range from 3 to 15, in particular 4 to 12, 40 Is 4 to 10 and o and p are independently a number in the range of 1 to 7;

as units (c) preferably those of the formula 45 0 (CH ₂ ) _n 0 or 0 (CH ₂ CH ₂ 0) _m where n is a number in the range from 3 to 15, in particular 4 to 12, particularly preferably 4 to 10 and m is a number in the range from 1 to 10; and

as units (d) preferably those of the formula

in which

A is (CH ₂ ) _n , 0 (CH ₂ ) _n 0 or (CH ₂ ) _o -0- (CH ₂ ) _p , n is a number in the range from 3 to 15, in particular 4 to 12, particularly preferably 4 to 10 and o and p independently represent a number in the range from 1 to 7.

The polyesters according to the invention also preferably contain dicarboxylic acid units of the formula as the non-flexible acid component

and as a non-flexible alcohol component diol units of the formula

being in the formulas above

L represents alkyl, alkoxy, halogen, COOR, OCOR, CONHR or NHCOR, X represents S, 0, N, CH ₂ or a single bond,

a single bond,

CH HH V-, _C H ₂ CH ₂ - / H -, - YH \ -, _χ-yoV—

or IQT ( ^~ ZT means and

in which

R ^{1 is} hydrogen, halogen, alkyl or phenyl and R represents alkyl or hydrogen,

The polyesters according to the invention optionally contain additional flexible diol units of the formula

_' ^where

R ^{1 is} hydrogen, halogen, alkyl or phenyl, A (CH ₂ ) _n , 0 (CH ₂ ) _n , S (CH ₂ ) _n or NR (CH ₂ ) _n and n is a number from 1 to 15.

The proportion of isosorbide, isomannide and / or isoidide units of the formulas:

(Isosorbide), (Isomannid) and (Isoidid) _f

is preferably in the range from about 1 to 15 mol%, in particular about 2.5 to 10 mol%, of the total content of structural units and in the range from about 2 to 30 mol%, in particular about 5 to 20 mol%, of the content Diol units. The units mentioned are advantageously distinguished by a very high twisting capacity and by great chemical and thermal stability.

The proportion of the units which make the polyester chain flexible is preferably about 1 to 50 mol%, in particular 5 to 30 mol%, of the total content of structural units.

The polyesters according to the invention can be produced by various types of polycondensation or by transesterification of polyesters with a mixture of acid component and acylated alcohol component. Typical types of polycondensation are, for example, the “HCl process”, the “silyl process” and the “transesterification process”. These processes are from HR Kricheldorf, N. Probst, among others; Macromol. Rapid. Commun. (1995) 16, 231 and N. Probst, HR Kricheldorf; High perform. Polym. (1995) 7, 461.

Acid component and alcohol component are used in a molar ratio of approximately 1: 1.

The reaction time can vary within a wide range. In general, it is 1 to 48 hours, in particular 1 to 24 hours.

The reaction is carried out at elevated temperature, generally in the range from 120 ° C. to 300 ° C., the temperature in this range also being able to be increased in stages.

In the "HCl process" the free diols are mixed with the dichlorides of the dicarboxylic acids in a suitable organic solvent, e.g. an ether such as dioxane, a chlorinated hydrocarbon such as 1, 1,2,2-tetrachloroethane, 1-chloronaphthalene or 1,2-dichlorobenzene, dissolved in a suitable reaction vessel. A pressure-resistant stirred vessel with gas inlet and outlet lines is suitable as the reaction vessel, for example.

The released hydrogen chloride is preferably removed in a gentle stream of nitrogen. The polyester obtained is dried at elevated temperature, for example at about 120 ° C. in vacuo. The polyester is optionally subjected to a cleaning step by redissolving in one of the abovementioned solvents and precipitating in methanol.

If the polymer is soluble in the solvent used, the organic phase is separated off and the polyester is obtained therefrom in a conventional manner, e.g. by taking up in methanol and filtering off. On the other hand, if the polymer precipitates out of the solvent or if gel formation occurs, the reaction mixture is diluted if necessary, e.g. with methanol and the polymer is filtered off.

In the "silyl process", the bissilylated diols are dissolved with the dichlorides of the dicarboxylic acids in the presence of a catalytic amount of a quaternary ammonium salt such as, for example, triethylbenzylammonium chloride in bulk or with one of the abovementioned solvents in a suitable reaction vessel described above. is heating. The polyester obtained is worked up as described above.

In the transesterification process, the free dicarboxylic acids with the acetylated diols in the presence of catalytic amounts of an alkali or alkaline earth metal oxide (for example MgO) or in the presence of zinc, tin, zirconium-manganese and bismuth salts are used in a suitable manner as described above Reaction vessel converted into substance. The polyester obtained is worked up as described above.

When a polyester (A) is esterified with free dicarboxylic acid (B) and acetylated diol (C), the reactants in the molar mass ratio A: B: C are from about 1 to 5: 1 to 5: 1 to 5, in particular about 1 : 2: 2 used. The reaction is carried out in a suitable reaction vessel, preferably in the presence of catalytic amounts of an early transition metal alkylate, e.g. Titanium tetrabutylate. Preferably, the reaction vessel is purged with nitrogen several times to remove air. The acetic acid released during the reaction is preferably removed in a gentle stream of nitrogen. The reaction is preferably continued in vacuo.

The polyester obtained is worked up as described above.

Usable polyesters are in particular polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and polyethylene naphthalate (PEN).

Of the production processes mentioned, the “HCl process”, the “silyl process” and the transesterification are particularly preferred.

The polyesters according to the invention have an inherent viscosity ηi _nh ^v ° n of approximately 0.1 to 3 dl / g, in particular approximately 0.1 to 1.5 dl / g, measured at 20 ° C. with c = 2 g / 1 in dichloromethane / Trifluoroacetic acid (volume ratio 4/1).

The polyesters according to the invention contain statistically distributed units.

The polymers according to the invention are particularly suitable as surface coating materials, as optical components and as chiral nematic colorants. They can be used as a color-imparting lacquer system for coating surfaces (eg as automotive lacquer or effect foils) or for the production of color pigments. The color-giving structure of the polymer can be achieved by rapidly cooling the chiral nematic phase be fixed. The polymers according to the invention advantageously have high glass transition temperatures (determined by means of DSC) of approximately 80 to 300 ° C., in particular approximately 100 to 220 ° C. At temperatures below the respective glass temperature, the coloring structure of the polymer is permanently preserved without additional crosslinking. Color pigments can be produced, for example, by detaching the oriented polymer film from the coated surface and grinding it into platelet-shaped pigments. In contrast to the processes described in DE-A 42 40 743, crosslinking of the polymer is not necessary. The polymer can be used as a coating system as a powder coating, in the melt or in solution (for example in N-methylpyrrolidone or dimethylformamide). In the simplest case, the system is oriented by tempering the coated surface and can be improved if necessary by the action of mechanical, electrical or magnetic forces.

The polymers according to the invention can be mixed with additional components to adjust the viscosity and the leveling behavior.

As such components, polymer binders and / or monomeric compounds, which can be converted into a polymeric binder by polymerization, are particularly suitable for paint-like coatings. As such agents are z. B. in organic solvents soluble polyesters, cellulose esters, polyurethanes, silicones, polyether- or polyester-modified silicones. Cellulose esters such as cellulose acetobutyrate are particularly preferably used.

If desired, stabilizers against UV and weather influences can also be added to the paints according to the invention. For this, z. B. derivatives of 2,4-dihydroxybenzophenone, derivatives of 2-cyan-3,3-diphenylacrylate, derivatives of 2,2 ', 4,4' -tetrahydroxybenzophenone, derivatives of orthohydroxyphenyl-benzotriazole, salicylic acid esters, orthohydroxyphenyl-S-triazines or sterically hindered amines. These substances can be used alone or preferably in the form of mixtures.

Pigments, dyes and fillers can also be added to the coating systems according to the invention.

Inorganic pigments include iron oxides, titanium dioxide and the various types of carbon black. Organic pigments are, for example, those from the class of the monoazo pigments (for example products which are derived from acetoacetic acid derivatives or from β-naphthol derivatives), monoazo dyes and their metal salts, such as β-oxynaphthoic acid dyes, disazo pigments, condensed disazo pigments, and disazo pigments, and Derivatives of naphthalene or perylene tetracarboxylic acid, anthraquinone pigments, thioindigo derivatives, azomethine derivatives, quinacridones, dioxazines, pyrazoloquinazolones, phthalocyanine pigments or basic dyes such as triarylmethane dyes and their salts.

Effect pigments such as aluminum particles, mica or coated mica, micas or the commercially available platelet-shaped effect pigments with different chemical structures can be considered as further pigments.

As fillers such. B. rutile, anatase, chalk, talc and barium sulfate.

Suitable as additional dyes are all which dissolve in the coating composition at least in a concentration of 0.1 mol%. Dichroic dyes are particularly suitable. The proportion of pigments, dyes or fillers is generally up to 40% by weight, preferably 0 to 10% by weight, based on the mass of the polymers according to the invention.

The surface coating can also be carried out by means of a printing process.

All common printing processes (e.g. high, low, flexo, offset, screen printing) can be used.

Methods suitable for coating and printing substrates according to the invention are described in WO 96/02597, to which reference is hereby made in full.

The following examples illustrate the invention without, however, restricting it thereto:

The physical properties of the polymers described in the examples are given in Table 1.

example 1

Tert.-butylhydroquinone (19 mmol), isosorbide (1 mmol), adipoyl chloride (2 mmol) and N- (4'-carboxyphenyl) trimellitic acid imide dichloride (18 mmol) and 1-chloronaphthalene (20 ml) were placed in a cylindrical Glass reactor given that with mechanical stirrer and gas inlet and outlet was provided. The reaction vessel was placed in an oil bath preheated to 120 ° C and the temperature was quickly raised to 230 ° C. At 230 ° C the reaction mixture was stirred in a gentle stream of nitrogen for 8 h. After cooling, the reaction product was dissolved in dichloromethane / trifluoroacetic acid (volume ratio 4: 1), precipitated in methanol and dried at 80 ° C. in vacuo. The polyester obtained is represented by Formula 1

described. The molar ratio v / w / x / z is 19/1/2/18 (la). Analogously, five other polyesters with the molar ratio v / w / x / z = 19/1/4/16 (lb), 19/1/6/14 (lc), 19/1/8/12 (ld), 18/2/6/14 (le) and 18/2/8/12 (lf) manufactured. The yield was 97% for the polyester ld and 98% for the polyesters la, lb, lc, le and lf.

Example 2

The polyesters were prepared analogously to Example 1. Instead of tert-butyl hydroquinone, phenyl hydroquinone was used. There were three polyesters of Formula 2

with the molar ratio v / w / x / z = 19/1/6/14 (2a), 18/2/6/14 (2b) and 18/2/8/12 (2c). The yield was 97% for polyester 2b and 98% for polyester 2a and 2c. Example 3

The polyester of formula 3

were prepared analogously to Example 1, with adipoyl chloride through the dichloride of compound I

(n = 6) was replaced. The molar ratio v / w / x / z was 19/1/2/18 (3a), 19/1/4/16 (3b), 19/1/8/12 (3c), 18/2/4/16 (3d) and 18/2/8/12 (3e). The yield was 97% for the polyesters 3c and 3e, 98% for 3b and 3d and 99% for 3a.

Another polyester of formula 3 was alternatively produced using the "silyl process". 0,0'-bistrimethylsilyl tert.-butylhydroquinone (19 mmol), 0, 0'-bistrimethylsilylisosorbide (1 mmol), the dichloride of compound I (2 mmol) and the dichloride of N- (4 '-carboxyphenyl) trimellitic acid imide ( 18 mmol) and triethylbenzylammonium chloride (10 mg) were placed in a cylindrical glass reactor with a mechanical stirrer and gas inlet and outlet. The reaction vessel was placed in a metal bath preheated to 150 ° C. The temperature was raised to 260 ° C and maintained for 3 hours. A vacuum was applied for 15 minutes. The polyester obtained was worked up as described above. The polyester contains the components of formula 3 in a molar ratio v / w / x / z = 19/1/2/18. The yield for this polymer (3fs) was 99%. Polymers 3a, 3b, 3d and 3e were also produced alternatively using the "silyl process". The corresponding process products are referred to as 3as, 3bs, 3ds and 3es. The yields were 99% for the polyesters 3as, 3bs and 3ds and 97% for 3es. Example 4

Analog to Example 2 was a polyester of formula 4

prepared, wherein adipoyl chloride was replaced by the dichloride of compound I with n = 6 (cf. Example 3). The molar ratio v / w / x / z was 19/1/4/16 (4a). The yield for the polyester 4a was 98%.

Example 5

Analogously to Example 3, a polyester of the formula 5 was obtained using the "silyl process"

prepared, the dichloride of compound I used containing four flexibilizing alkylene groups (n = 4). The molar ratio v / w / x / z was 19/1/4/16 (5a). The yield for the polyester 5a was 98%.

Example 6

Analogously to Example 3, two polyesters of the formula 6 were obtained using the silyl process

prepared, the dichloride of compound I used containing ten flexibilizing alkylene groups (n = 10). The molar ratio v / w / x / z was 19/1/4/16 (6a) and 18/2/4/16 (6b). The yield for each of 6a and 6b was 99%.

Example 7

In a glass reactor equipped with a mechanical stirrer and an inlet or outlet for nitrogen, N- (4-carboxyphenyl) trimellitic acid imide dichloride (5 mmol), tert-butylhydroquinone (4.5 mmol), hexanediol (0, 25 mmol) and isosorbide (0.25 mmol) weighed out. After adding 5 ml of 1-chloronaphthalene, the reactor was heated to 230 ° C. using a metal bath. At this temperature, stirring was carried out for 8 hours under a gentle stream of nitrogen. After cooling, the crude product was dissolved in a mixture of trifluoroacetic acid and dichloromethane (volume ratio 1: 4) and precipitated by pouring it into cold methanol. After filtering off the product, it was dried in a vacuum drying cabinet at 80 ° C. for 2 days. The molar ratio u / v of the resulting polymer of formula 7

was 4.5 / 0.25 (7a). In an analogous manner, two further polymers of the formula 7 were produced with the molar ratio u / v = 4.25 / 0.5 (7b) and 4 / 0.75 (7c). The yield was 97% for polymer 7a and 99% for polymers 7b and 7c.

Example 8

Analogously to Example 7, the dichloride of compound I (see Example 3) with six flexibilizing alkylene groups (n = 6) (5 mmol) and terephthalic acid dichloride (5 mmol) with tert-butylhydroquinone (9.5 mmol) and isosorbide (0 , 5 mmol) implemented. The resulting polyester of Formula 8

(8a) was obtained in 97% yield.

Example 9

Analogously to Example 8, the dichloride of compound I with four flexibilizing alkylene groups (n = 4) (10 mmol) was reacted with tert-butylhydroquinone (9.5 mmol) and isosorbide (0.5 mmol). The resulting polyester of Formula 9

(9a) was obtained in 98% yield. Example 10

Analogously to Example 9, the dichloride of compound I was without flexibilizing alkylene groups (n = 0) (5.25 mmol), adipoyl chloride (3 mmol) and 2, 6-naphthalenedicarboxylic acid dichloride

(1.75 mmol) with tert-butyl hydroquinone (9.5 mmol) and isosorbide (0.5 mmol). The resulting polyester of Formula 10

(10a) was obtained in 99% yield. Three other polyesters with the molar ratio v / w / x / y / z = 9.5 / 0.5 / 3/7/0 (10b), 9/1/3/7/0 (10c) and 9 were used analogously / 1/3 / 5.25 / 1.75 (lOd). The yield for each of these three polyesters was 98%.

Example 11

Polyethylene terephthalate (10 mmol), N- (4'-carboxyphenyl) trimellitic acid imide were placed in a glass reactor equipped with a mechanical stirrer and an inlet or outlet for nitrogen

(20 mmol), 1,4-diacetoxy-2-methylbenzene (16 mmol), diacetoxy isosorbide (4 mmol) and 20 mg titanium tetrabutylate were weighed out. The reactor was treated with dimethyldichlorosilane before use and washed with dry ether. The reactor was placed in a metal bath preheated to 120 ° C. To completely remove the air in the reactor, it was evacuated and nitrogen was passed through four times. The temperature was then quickly raised to 280 ° C. After 30 min there was a homogeneous melt which was stirred for 1 h. The released acetic acid was removed in a gentle stream of nitrogen. A vacuum was applied for 6 hours with continued stirring. After cooling, the crude product was dissolved in a mixture of trifluoroacetic acid and dichloromethane (volume ratio 1: 4), precipitated by pouring it into cold methanol and drying at 80 ° C. The resulting mixed polyester was obtained with a yield of 98%. Table 1 shows the physical properties (inherent viscosity (ηin _h ), glass transition temperature (T _g ) and clearing point (T), the observed textures of the liquid-crystalline phases and the interference colors of polymers 1 to 11.

Table 1

^!) measured at 20 ° C, c = 2 g / 1 in dichloromethane / trifluoroacetic acid (4/1) ⁴⁵ ) DSC measurement, heating rate 20 ° C / min

3 ⁾ Optical microscope heating rate 10 ° C / min

Claims

claims

1. Chiral nematic polyesters with flexible chains, which comprise isosorbide, isomannide and / or isoidide units, and to make the chains more flexible, contain at least one unit which is selected from (and derived from)

(a) aliphatic dicarboxylic acids,

(b) aromatic dicarboxylic acids with a flexible spacer, (c) α, ω-alkanediols,

(d) Diphenols with flexible spacers and

(e) condensation products of a polyalkylene terephthalate or polyalkylene naphthalate with an acylated diphenol and an acylated isosorbide.

Chiral nematic polyesters according to Claim 1, which as units (a) are those of the formula

—OC— (CH ₂ ) _n —CO—.

contain in particular adipic acid, where n is a number in the range from 3 to 15;

as units (b) those of the formula

included, where

A stands for (CH ₂ ) _n , 0 (CH ₂ ) _n 0 or (CH ₂ ) _o -0- (CH ₂ ) _p , n stands for a number in the range from 3 to 15, in particular 4 to 10, and o and p independently represent a number in the range from 1 to 7;

as units (c) those of the formula

—0 (CH ₂ ) _n —0 or —0 (CH ₂ —CH ₂ —0) _m , where n is a number in the range from 3 to 15, in particular 4 to 10 and m is a number in the range from 1 to 10; and

as units (d) those of the formula

included, where A is (CH ₂ ) _n , 0 (CH ₂ ) _n O or (CH ₂ ) _o -0- (CH ₂ ) _p , n is a number in the range from 3 to 15, in particular 4 to

10 is and o and p are independently a number in the range of 1 to 7.

Chiral nematic polyester according to claim 1 or 2, which is a non-flexible acid component units of the formula

and as a non-flexible alcohol component diol units of the formula

included, in the formulas above

L represents alkyl, alkoxy, halogen, COOR, OCOR, CONHR or NHCOR, X represents S, 0, N, CH ₂ or a single bond, A a single bond,

or olo means and

R ^{1 is} hydrogen, halogen, alkyl or phenyl and R is alkyl or hydrogen.

Chiral nematic polyesters according to Claim 1 or 2, which contain 1 to 15 mol%, in particular 2.5 to 10 mol%, of isosorbide, mannid and / or idid units.

5. Chiral nematic polyester according to one of the preceding

Claims containing 1 to 50 mol%, in particular 5 to 30 mol%, of the units which flexibilize the polyester chain.

6. Chiral nematic polyester according to one of the preceding

Claims whose inherent viscosity is about 0.10 to 3 dl / g, in particular about 0.1 to 1.5 dl / g, measured at 20 ° C.

7. Chiral nematic polyester according to one of the preceding claims, the glass transition temperature is in the range of about 80 to 300 ° C, in particular about 100 to 220 ° C.

5 8. Use of the chiral nematic polyester according to one of the preceding claims as an optical component or as a surface coating material.

9. Use of the chiral nematic polyester according to one of the claims 1 to 7 as a colorant, in particular as a coloring component of coating systems for coating surfaces or as a component of printing inks.

10. Use of the chiral nematic polyester according to one of 5 claims 1 to 7 in cosmetic products, in particular

Nail polishes and lipsticks.

11. Pigments containing chiral nematic polyester according to one of claims 1 to 7. 0

12. coating compositions containing at least one chiral nematic polyester according to one of claims 1 to 7 or at least one pigment according to claim 11.

5 13. A process for the production of chiral nematic polyester according to one of claims 1 to 7, characterized in that free diols are reacted with dicarboxylic acid dichlorides in an inert aromatic solvent, in particular 1-chloronaphthalene. 0

14. A process for the preparation of chiral nematic polyesters according to one of claims 1 to 7, characterized in that silylated diols are reacted in bulk with dicarboxylic acid dichlorides.

35

15. A process for the production of chiral nematic polyester according to one of claims 1 to 6, characterized in that acetylated diols are reacted with free dicarboxylic acids.

16. A process for the production of chiral nematic polyester according to any one of claims 1 to 7, characterized in that a mixture of free dicarboxylic acids and acetylated diols with a polyester, in particular with polyethylene terephthalate, polybutylene terephthalate or polyethylene naphthalate.

45 sets.