EP1029021A1

EP1029021A1 - Cholesteric oligomers with cross-linked end groups

Info

Publication number: EP1029021A1
Application number: EP98961151A
Authority: EP
Inventors: Peter Schuhmacher; Hans R. Kricheldorf; Thorsten Krawinkel
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1997-11-06
Filing date: 1998-11-06
Publication date: 2000-08-23
Also published as: JP2001522927A; KR20010031812A; DE19749123A1; WO1999024529A1

Abstract

The invention relates to cholesteric oligomers of formula (I) [(Zn?1-Y1-)\(A-Y2-)¿q\(B-Y3-)p\Z2], wherein n represents a value from 0 to 1 in the agent, q represents a value from 0.1 to 2 in the agent, p represents a value from 1 to 20 in the agent, A represents a chiral group, B represents a mesogene group. Y?1, Y2 and Y3¿, independent of one another, represent a group of formula -CO-O-, -O-CO- or -O-CO-O-, whereby the q-units (A-Y2-) and the p-units (B-Y3-) exist in any sequence, the q-groups A are the same or different and the p-groups B are also the same or different. In addition, Z?1 and Z2¿, independent of one another, represent a group of formula W-Q-, wherein Q represents a chemical bonding or one or multiple substituted alkylene-spacers or arylene-spacers; and W represents a cross-linked heterocyclic group. The invention also relates to a method for producing and utilizing said cholesteric oligomers.

Description

Cholesteric oligomers with crosslinkable end groups

description

The invention relates to cholesteric oligomers with crosslinkable end groups, processes for their preparation and their use.

When heating anisotropic substances, liquid-crystalline phases, so-called mesophases, can occur. The individual phases differ by the spatial arrangement of the molecular centers on the one hand and by the molecular arrangement with regard to the longitudinal axes on the other hand (G. Gray, P A. insor, 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 created 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 power 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. Thus, by incorporating chiral parts of the molecule into mesogenic acrylic acid esters and orientation in the chiral nematic phase, e.g. B. after photocrosslinking, a stable, colored network can be produced, the concentration of chiral component of which is then no longer changed can (G. Galli, M. Laus, A. Angelon, Makromol. Chemie 187, 2289 (1986)). By admixing 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, a statistical chiral nematic network can be obtained by statistical hydrosilylation of mixtures of cholesterol derivatives and acrylate-containing mesogens with defined cyclic siloxanes and subsequent photopolymerization, in which the chiral component can have a share of up to 50% of 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, Freiburg, 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 known, e.g. B. from S. Vilasagar, A. Blumstein, Mol. Cryst. Liq. Cryst. (1980), 56 (8), 263-9; A. Blumstein, S. Vilasagar, S. Ponratham, 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, Pollimo (1986), 10 (6), 635-40; JMG Cowie, HH Wu, Makromol. Chem. (1988), 189 (7), 1511-16; VV Zuev, IG Denisov, SS Skorokhodov, Vysokomol. 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 Vysokomol. 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 such. B. limited in terms of their mechanical properties.

DE-A-19 538 700 describes cholesteric phase-forming polymers which have at least one bifunctional chiral molecular building block, at least one bifunctional achiral or racemic molecular building block and at least one bifunctional molecular building block which can be any chiral or achiral, and which of the first two Molecular building blocks is different. The polymers described are as molding compound granules for further processing, for. B. in injection molding, suitable. They can also be processed into pigments for iridescent paints.

EP-A-682 092 describes paints based on chiral nematic polymers containing cinnamic acid groups, which can be crosslinked by UV radiation, but not thermally. Examples are polyesters which have been prepared by polycondensation of dicarboxylic acids and diols.

DE-A-44 41 651 discloses a process for the surface coating of substrates with a coating composition which contains at least one polymerizable, low-molecular 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 describes a method for coating or printing substrates 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, the color impression of which depends on the viewing angle and the platelet-shaped pigments made from oriented, three-dimensionally crosslinked substances of liquid-crystalline structure. contain chiral phase. Three-dimensionally crosslinkable polyorganosiloxanes are described as particularly preferred substances.

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 which is dependent on the viewing angle and which 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 lacquer or an effect lacquer 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 color-retaining at 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-686 674 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-shaped structure and a thickness of 7 μm. They contain oriented cross-linked substances of liquid-crystalline structure with a chiral phase, preferably polyorganosiloxanes.

EP-A-601 483 and the priority application on which it is based DE-A-42 40 743 describe pigments with coloration which 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 optionally further dyes and pigments. DE-A-19 502 413 describes a pigment with a color which is dependent on the viewing angle and which has been obtained by three-dimensional crosslinking of oriented substances of liquid-crystalline structure with a chiral phase. In order to make such a pigment contain color compared to elevated temperatures, it is proposed that the crosslinking be carried out in the presence of at least one further color-neutral compound containing at least two crosslinkable double bonds.

DE-A-19 704 506 describes liquid-crystalline chiral nematic polyesters with flexible chains which comprise isosorbide, isomannide and / or isoidide units. The polyesters are not crystalline and form Grandjean textures that can be frozen below the glass transition temperature when they cool. They are therefore particularly useful as surface coating materials.

From P.M. Hergenrother, Encyclopedia of Polymers 1, 61 (1985), acetylene-terminated prepolymers are known (pp. 61-86) and polymers that contain propargyl groups in the side chains (pp. 82f). The connection described can be thermally crosslinked.

From P.M. Hergenrother et al., Journal of Polymer Science: Part A: Polymer Chemistry, 32, 3061-3067 (1994), phenylacetylenyl-terminated oligo- / polyimides are known which are not cholesteric and can be crosslinked at high temperatures without the release of volatile substances. The crosslinked polymers described are said to be more stable to thermal oxidation than those made from acetylene-terminated oligomers.

US-A-4, 166, 168 describes non-cholesteric acetylene-terminated polyimide esters and their thermal crosslinking for the production of insoluble non-meltable polymers without the formation of by-products.

Wang, C.-S. and Hwang, H.-J. describe non-cholesteric naphthalene units and their thermal crosslinking in Journal of Polymer Science, Part A: Polymer Chemistry, 34, 1493-1500 (1996) containing bismaleimide. The crosslinking products are thermally stable, have a high resistance to chemicals and absorb little moisture.

Non-cholesteric liquid-crystalline polymers are known from Hoyt, AE and Benicewicz, BC, Journal of Polymer Science: Part A: Polymer Chemistry, 28, 3403-3415 and 3417-3427 (1990), which are obtained by polymerizing with maleimide, norbornene dicarboxylic acids. rhimidic and methylnorbornenedicarboxylic acid: lmid groups terminated Monomers are available. The maleimide-terminated monomers crosslink faster than the methylnorbornene dicarboximide-terminated monomers.

5 Hao, J. et al. describe in Polymer, 37, 16, 3721-3727 (1996) the synthesis of maleimide-terminated polysiloxanes by reacting N- (4-hydroxyphenyl) maleimide with dichlorodimethylsilane and subsequent reaction with hydroxyl-terminated polysiloxane. The incorporation of the maleimide-terminated polysiloxanes in a matrix of 10 4, 4 '-Bismaleimidodiphenylmethan (BMI) in an amount of about

20% by weight leads to a considerable mechanical reinforcement of the matrix.

From Lin, K.-F. et al., Polymer, 37, 21 4729-4737 (1996), the 15 reaction of various non-cholesteric bismaleimides with allylamines is known. The crosslinking products have outstanding mechanical and thermal properties.

Meador, M.A.B. et al. describe in high perform. Polym., 8, 20 363-379 (1996) the effects of cyclic heating and cooling of samples of a non-cholesteric norbomenyl-terminated polyimide resin (PMR-15), its weight, microhardness and crack formation.

25 From Barton, J.M. et al., Polymer, 33, 17, 3664-3669 (1992), non-cholesteric aryl bismaleimides and biscitraconimides are known. In particular, the thermal polymerization kinetics of these compounds and the effects of the purity of the monomers on the characteristics of the thermal polymerization

30 tion examined.

Habas, J.P. et al. describe in high perform. Polym., 8, 407-426 (1996) a new non-cholesteric high temperature resin (IP960) as an alternative to the above-mentioned PMR-15. The

35 IP960 prepolymers are also norbornenedicarboximide-terminated, differ from the PMR-15 prepolymers in that a carbonyl function is replaced by a C-OH group. In contrast to PMR-15, IP960 should be storable in dry powder form.

40

US Pat. No. 5,475,133 describes thermally crosslinkable diesters which are terminated by 4-propargyloxybenzoic acid or p-propargyloxyphenyloxy radicals. Some of the diesters described by way of example have liquid-crystalline properties, but they do

45 are lost far below the crosslinking temperature. It will no example of crosslinking in the liquid-crystalline phase.

WO-A-97/00600 describes polymerizable liquid-crystalline compounds which contain a mesogenic group and are terminated with polymerizable residues. By polymerization with compounds that contain a chiral component, cholesteric polymerization products can be produced, which can be comminuted, for example, into pigments. The described compounds and compositions containing them are said to be distinguished by favorable liquid-crystalline phase temperature ranges and to be usable in optical display devices and in cholesteric liquid-crystalline colorants.

DE-A-19 631 658 describes chiral nematic polycarbonates which are produced by various types of polycondensation of diols with phosgene or diphosgene. Photoreactive and / or thermally crosslinking groups can be condensed in the form of the corresponding diol compounds. Cinnamic acid chloride can be added as a chain terminator.

DE-A-19 504 913 describes chiral nematic polyesters with chiral diol components with a strong twisting action, in particular dianhydro sugars, and broad liquid-crystalline phase regions. The polymers can contain cinnamic acid groups which can be crosslinked via a [2 + 2] photocycloaddition.

From DE-A-19 717 371 propargyl terminated, nematic or cholesteric oligo- / polyesters, oligo- / polycarbonates or nematic or cholesteric mixtures containing them are known. The compounds described can be thermally crosslinked at a temperature of about 180 to 340 ° C. They are particularly useful as surface coating materials.

One of the main problems in the provision of nematic or cholesteric oligo- / polyesters or oligo- / polycarbonates is the fixation of their supermolecular order, which determines the desired optical properties of the oligo- / polymers. Various methods for fixing the supermolecular order of polymers by crosslinking via σ bonds have recently been published (HR Kricheldorf, N. Probst, M. Gurau, M. Berghahn; Macromolecules (1995) 28, 6565; 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 photo-crosslinking of UV-sensitive chiral nematic polymers. There is a considerable need for cholesteric oligomers with, in particular, thermally crosslinkable end groups, the supermolecular order of which is not destroyed by the crosslinking and which are thus crosslinkable in the anisotropic phase.

The invention is therefore based on the object of providing further cholesteric oligomers which can be crosslinked in the anisotropic phase, in particular thermally, without eliminating the cholesteric effect.

The present invention relates to cholesteric oligomers of the formula I.

( _Z l_γl _) \ (A-γ2-) \ (B-γ3-) \ Z ² n ' ^v qp (I)

wherein

n stands on average for a value from 0 to 1,

q stands on average for a value from 0.1 to 2,

p stands on average for a value from 1 to 20,

A represents a chiral group,

B represents a mesogenic group,

Y ¹ , Y ² and Y ³ independently of one another represent a group of the formula -CO-O-, -O-CO- or -O-CO-O-,

wherein the q units (AY ² -) and the p units (BY ³ -) are in any order, the q groups A are the same or different and the p groups B are also the same or different, and

Z ¹ and Z ² independently of one another represent a group of the formula WQ-,

wherein Q represents a chemical bond or a mono- or polysubstituted alkylene or arylene spacer; and

W represents a crosslinkable heterocyclic group.

The cholesteric oligomers according to the invention have some surprising advantages:

a) The oligomers can be crosslinked to polymer networks in the anisotropic phase without destroying the supermolecular order, so that the cholesteric effect is permanently fixed.

b) The polymeric networks are resistant to the effects of temperature and weather.

c) The starting materials used for the production of the oligomers are easy to synthesize and clean and are therefore economically accessible.

Preferred cholesteric oligomers are those in which W is selected from residues of the formula

in which E represents a crosslinkable alkenylene group, and the radicals R can be the same or different and are hydrogen or Cχ-C ₄ alkyl, such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl or tert-butyl. E preferably stands for

wherein the radicals R have the meaning given above. The groups A are preferably selected from chiral groups which differ from aliphatic ethers or thioethers; araliphatic ethers or thioethers; .Amino acids, especially L-proline; Prolinol; Camphoric acid or lithocholic acid; Resin acids, in particular .Abietic and dehydroabietic acid; Sugars, especially pentoses and hexoses; Derive binaphthyl or biphenyl derivatives or from optically active glycols or diols;

The groups B are preferably selected from optionally by fluorine, chlorine, bromine, cyano, -CC alkyl, -C-alkoxy, hydroxy or nitro substituted, linear aliphatic, isocycloaliphatic, heterocycloaliphatic, isoaromatic or heteroaromatic groups or among compounds , the 2 to 4 such groups, linked by chemical bonds or via bridge members, such as oxygen, sulfur, -CO-O-, -O-CO-O-, -CO-N (R) - or -N (R) - CO- included.

Q preferably represents a chemical bond or an arylene radical optionally substituted with one or more groups selected from C 1 -C alkoxy, fluorine, chlorine, bromine, cyano, hydroxyl or nitro, in particular a phenylene or naphthylene radical.

Groups A are particularly preferably selected independently of one another from groups of the formula

being in the formulas above

represents H, alkyl, alkoxy, alkylthio, halogen, COOR, OCOR, CONHR or NHCOR, R is C 1 -C 4 -alkyl or hydrogen and

X represents S, 0, N, CH ₂ or a single bond.

The groups B are particularly preferably selected independently of one another from groups of the formula

where each of the phenyl groups or the naphthyl group may have 1, 2 or 3 substituents which are selected independently of one another from straight-chain or branched Cχ-C-alkyl, Cι-C ₄ alkoxy, fluorine, chlorine, bromine, cyano, hydroxy or nitro , where in the formulas above

W 'represents NR, S, O, (CH ₂ ) _g O (CH ₂ ) _h , (CH ₂ ) _m or 0- (CH ₂ ) _m -0,

G represents a single bond, 0 or S,

R represents alkyl or hydrogen,

m represents an integer from 1 to 15, and

g and h are independently integers from 0 to 10.

Very particularly preferred oligomers according to the invention are those in which The groups A are selected independently of one another under groups of the formula

1 . in particular

The groups B are selected independently of one another under groups of the formula

and - (CH ₂ ) _m -, in particular (a), (d) and / or (e), where (f)

where m is an integer from 4 to 12;

m represents an integer from 4 to 10;

the groups Y independently of one another are -CO-O- or -O-CO-, and

stands for or.

The oligomers of the invention preferably have the formula

1 q for 0.1 to 1, p for 2 and n for 1.

The oligomers according to the invention contain the groups A, B and Z in the molar ratio A / B / Z from about 0.05 to 2 / about 1 to 30 / about 0.5 to 5, in particular from about 0.1 to 1 / about 4, 5 to 20 / about 1.5 to 2.5 condensed.

The inherent viscosity of the cholesteric oligomers is approximately 0.1 to 3 dl / g, in particular approximately 0.1 to 1.5 dl / g, particularly preferably approximately 0.1 to 0.5 dl / g, measured at 20 ° C. with c =

2 g / 1 in dichloromethane / trifluoroacetic acid (volume ratio 4/1). The glass transition temperature (determined by means of DSC) of the oligomers according to the invention is approximately in the range from 80 to 300 ° C., in particular approximately 90 to 200 ° C., particularly preferably approximately 90 to 140 ° C.

By heating the oligomers according to the invention, preferably at a temperature of about 200 to 350 ° C., in particular about 250 to 300 ° C., cholesteric polymeric networks can be obtained, which are a further subject of the present invention.

The cholesteric oligoesters or oligocarbonates according to the invention can be prepared by various condensation reactions which are familiar to the person skilled in the art and which, for polyesters, include H.R. Kricheldorf, N. Probst; Macromol. Rapid. Commun., 16, 231 (1995) and N. Probst, H.R. Kricheldorf; High perform. Polym., 7, 461 (1995) and for polycarbonates are known from DE-A-19631658.

The oligoesters according to the invention are preferably produced at elevated temperature, but below the crosslinking temperature of the reactants or reaction products, generally in the range from 120 ° C. to 250 ° C., the temperature in this range also being able to be increased in stages. However, it is also possible to use the oligoesters according to the invention at low temperature, e.g. B. in the range of -10 to +50 ° C.

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

In the condensation process preferred for the preparation of the oligoesters according to the invention, free diols of the formula A- (OH) _{2 are} activated with activated dicarboxylic acids, in particular with dicarboxylic acid dichlorides of the formula B- (C0C1) ₂ and with groups or radicals of the formula Z-OH and, if appropriate with free diols Formula B- (OH) ₂ in a suitable inert solvent, especially an inert organic solvent, e.g. B. N, N-dimethylacetamide, an ether such as dioxane or tetrahydrofuran, a chlorinated hydrocarbon such as dichloromethane, dichloroethane, 1, 1-2,2-tetrachloroethane, 1,2-dichlorobenzene or particularly preferably 1-chloronaphthalene for the reaction brought. The chain length of the oligomers according to the invention can be adjusted via the amount of groups or residues of the formula Z-OH used and / or via the time of their addition. The condensation is expediently in the presence of a base, for. B. pyridine, N-methylmorpholine or a trialkylamine, especially triethylamine as HCl acceptor. A pressure-resistant stirred tank with gas inlet and outlet lines, for example, is suitable as the reaction vessel. The process is preferably carried out under nitrogen. The oligoester obtained is dried at elevated temperature, for example at about 80 ° C. in vacuo. If necessary, the oligoester is subjected to a cleaning step by redissolving in one of the abovementioned solvents and precipitating with methanol. If the oligomer is soluble in the solvent used, the organic phase is separated off and the oligoester is obtained therefrom in a conventional manner, eg. B. by taking up in methanol and filtering off. However, if the oligomer precipitates out of the solvent or if gel formation occurs, the reaction mixture is optionally diluted, e.g. B. with methanol, and the oligomer is filtered off.

The oligocarbonates according to the invention are generally prepared at a reaction temperature which is approximately in the range from 0 ° C. to ambient temperature. However, it can also be higher, in particular to complete the reaction. The reaction time is variable over a wide range; it is generally 10 minutes to 24 hours, especially 10 minutes to 5 hours.

In the condensation process preferred for producing the oligocarbonates according to the invention, groups of the formulas A- (0H) ₂ and B- (OH) _{2 are dissolved} in an amine, preferably a tertiary or aromatic amine, for example pyridine or triethylamine. Groups or radicals of the formula Z-OH are dissolved in the same solvents, either separately from the diols or together with them. Phosgene, diphosgene or triphosgene is in a suitable organic solvent, e.g. B. an ether such as tetrahydrofuran or dioxane, a chlorinated hydrocarbon such as dichloromethane, 1, 1-2,2-tetrachloroethane, 1-chloronaphthalene, chlorobenzene or 1,2-dichlorobenzene. This solution is added to the solution containing the diols and optionally the groups or the residues of the formula Z-OH with stirring. The groups or radicals of the formula Z-OH are not together with the diols dissolved, the solution containing Z-OH is added to the ongoing condensation reaction. The chain length of the oligomers according to the invention can be set via the amount of groups or radicals of the formula Z-OH used and / or via the time of addition. If the oligomer is soluble in the solvent used, the organic phase is separated off and the oligocarbonate is obtained therefrom in a conventional manner, e.g. B. by taking up in methanol and filtering off. If, on the other hand, the oligomer precipitates out of the solvent or if gel formation occurs, the reaction mixture is diluted, if necessary, e.g. B. with methanol, and the oligomer is filtered off. As an alternative to phosgene, diphosgene or triphosgene, the chlorinated carbonic acid esters or carbonic acid diesters of the alcohols or diols to be condensed can also be used.

The oligomers according to the invention contain groups A and B in a statistical distribution.

The cholesteric oligomers according to the invention can be used in particular as surface coating material or for the production of pigments.

The pigments can be prepared in a customary manner by applying the cholesteric oligomers according to the invention to a surface using one of the customary application methods (knife coating, pouring, spraying, etc.), optionally reorienting the oligomer layer, crosslinking the oligomer layer, detaching the oriented crosslinked film the surface and grinding to platelet-shaped pigments. Single or multilayered pigments which contain cholesteric oligomers according to the invention or cholesteric polymer networks according to the invention are therefore a further subject of the present invention.

The cholesteric polymeric networks according to the invention or the pigments according to the invention can be used in particular in the vehicle and vehicle accessories sector, in the EDP, leisure, sports and games sector, as optical components, such as polarizers or filters, in the cosmetics sector, in the textile, leather or jewelry sector, be used in the field of gifts, in writing utensils or on spectacle frames, in the construction sector, in the household sector and in all types of printed matter, as well as for the production of paints and varnishes.

The color effects which can be achieved by the cholesteric polymeric networks or pigments according to the invention also include, owing to the diversity of the reflection wavelengths which can be achieved the UN and IR ranges and of course the range of visible light.

If the pigments according to the invention are applied to banknotes, check cards, other cashless means of payment or identity cards (for example by known printing processes) or incorporated into them, this makes identical copying, in particular the counterfeiting of these objects, considerably more difficult. Another object of the present invention is therefore the use of the polymeric networks or pigments according to the invention for the processing of objects, in particular banknotes, check cards or other cashless means of payment or identification, which makes counterfeiting difficult. Another object of the present invention is the use of the polymeric networks or pigments according to the invention for coating everyday objects and for painting vehicles.

The present invention further relates to compositions, in particular coating or coating agents, paints or lacquers, which contain pigments according to the invention.

The compositions according to the invention generally contain, in addition to the pigments according to the invention, customary leveling agents, binders and one or more substances which are or are selected from water-based paints, for example in the form of aqueous dispersions such as P.MA, SA, polyvinyl derivatives, PVC, Polyvinylidene chloride, SB-Copo, PV-AC-Copo-resins, or in the form of water-soluble binders, such as shellac, maleic resins, colophony-modified phenolic resins, linear and branched, saturated polyesters, aminoplast-crosslinking, saturated polyesters, fatty acid -modified alkyd resins, plasticized urea resins, or in the form of water-dilutable binders, such as PUR dispersions, EP resins, urea resins, melamine resins, phenolic resins, alkyd resins, alkyd resin emulsions, silicone resin emulsions; Powder sheets, such as powder coatings for TRIBO / ES, such as polyester coating powder resins, PUR coating powder resins, EP coating powder resins, EP / SP hybrid coating powder resins, P.MA coating powder resins, or powder coatings for fluidized bed sintering, such as thermoplasticised EPS, LD- PE, LLD-PE, HD-PE; solvent-based paints, for example as one- and two-component paints (binders), such as shellac, rosin rosin esters, maleate resins, nitrocelluloses, rosin-modified phenolic resins, physically drying, saturated polyesters, aminoplast-crosslinking, saturated polyesters, Isocyanate-crosslinking, saturated polyesters, self-crosslinking, saturated polyesters, alkyds with saturated fatty acids, linseed oil alkyd resins, soybean oil resins, sunflower menölalkyd resins, safflower oil alkyd resins, ricinenalkyd resins, wood oil / linseed oil alkyd resins, mixed oil alkyd resins, resin-modified alkyd resins, styrene / vinyl toluene-modified alkyd resins, acrylated alkyd resins, urethane-modified alkyd resins, silicone-modified alkyd resins, epoxy resins, epoxy resins, epoxy resins , non-plasticized urea resins, plasticized urea resins, melamine resins, polyvinyl acetals, non-crosslinking P (M) A homo- or copolymers, non-crosslinking P (M) A homo- or copolymers with non-acrylic monomers, self-crosslinking P (M) A-homo- or Copolymers, P (M) A copolymers with other non-acrylic monomers, externally crosslinking P (M) A homopolymers or copolymers, externally crosslinking P (M) A copolymers with non-acrylic monomers, acrylate copolymerization resins, unsaturated hydrocarbon resins, organically soluble cellulose compounds, silicone Combination resins, PUR resins, P-resins, peroxide-curing, unsaturated synthetic resins, radiation-curing synthetic resins rze, containing photoinitiator, radiation-curing synthetic resins free of photoinitiator; solvent-free paints (binders), such as isocyanate-crosslinking, saturated polyesters, PUR 2K resin systems, PUR-IK resin systems moisture-curing, EP resins, as well as synthetic resins - individually or in combination - such as acrylonitrile-butadiene-styrene copolymers , BS, cellulose acetate, cellulose acetobutyrate, cellulose acetopropionate, cellulose nitrate, cellulose propionate, synthetic horn, epoxy resins, polyamide, polycarbonate, polyethylene, polybutylene terephthalate, polyethylene terephthalate, polymethyl methacrylate, polypropylene, polystyrene, polypropylene, polystyrene, polystyrene, polypropylene, polystyrene, polystyrene, polypropylene, polystyrene, polystyrene, polypropylene, polystyrene, polystyrene, polypropylene, polystyrene, polystyrene, polypropylene, polystyrene, polystyrene, polypropylene, polystyrene, polystyrene, polypropylene, polystyrene, polystyrene, polypropylene, polystyrene, polystyrene, polypropylene, polystyrene, polystyrene, polypropylene, polystyrene, polypropylene, polystyrene, polystyrene, polypropylene, polystyrene, polypropylene, polystyrene, polypropylene, polystyrene, polypropylene, polypropylene, -Acrylonitrile copolymers, unsaturated polyester resins as granules, powder or casting resin.

The compositions according to the invention can also contain stabilizers against UV and weather influences and additionally inorganic or organic pigments.

The pigments according to the invention can be incorporated individually or in mixtures into the compositions according to the invention and, if appropriate, additionally aligned there by methods which trigger shear forces. Suitable methods for aligning the pigments according to the invention are, for example, printing or knife coating.

Both the coating of surfaces with cholesteric oligomers according to the invention and the coating of articles of daily use with compositions according to the invention can be carried out by customary surface coating methods, such as knife coating, air knife coating, squeeze coating, impregnation coating, reverse roller coating, transfer roller coating, "kiss coating", Spray coating, spin coating or cast coating, as described in DE-A-19740181, consequences. Other suitable surface coating processes are the customary printing processes (eg high, low, flexographic, offset or screen printing), which are described, for example, 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 compounds described in the examples are given in Tables 1 to 3.

Examples:

The monomers shown in Scheme 1 were dissolved in 20 ml of 1-chloronaphthalene in the amounts indicated in Scheme 2 and placed in a cylindrical glass reactor which was equipped with a mechanical stirrer and gas inlet and outlet. The reaction vessel was placed in an oil bath preheated to 120 ° C and the temperature was quickly raised to 200 ° C. The reaction mixture was stirred at 200 ° C under nitrogen for 6 hours. 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.

In this way, 16 cholesteric oligoesters were produced which were thermally crosslinkable in the anisotropic phase.

Scheme 1: Structural formulas of the monomers used (Me stands for methyl)

(C)

(O)

(E)

(H) (J)

(K) (L) (X) Scheme 2: Amounts used (in mmol) of the monomers used

Oligomer 1: 10 M + 40 C + 15 E + 45 K + 5 X Oligomer 2: 10 M + 20 C + 10 E + 25 K + 2.5 X

Oligomer 3: 10 M + 20 C + 10 E + 23.75 K + 1.25 X

Oligomer 4: 10 M + 10 C + 5 E + 9.375 K + 0.625 X

Oligomer 5: 10 M + 20 C + 10 O + 23.75 K + 1.25 X

Oligomer 6: 10 M + 10 C + 5 0 + 9.375 K + 0.625 X Oligomer 7: 10 M + 20 C + 20 H + 32.5 K + 2.5 X

Oligomer 8: 10 M + 10 C + 10 H + 14.375 K + 0.625 X

Oligomer 9: 10 M + 20 C + 10 O + 23.75 L + 1.25 X

Oligomer 10: 10 M + 10 C + 5 0 + 9.375 L + 0.625 X

Oligomer 11: 10 M + 20 C + 10 J + 23.75 K + 1.25 X Oligomer 12: 10 M + 10 C + 5 J + 9.375 K + 0.625 X

Oligomer 13: 10 N + 20 C + 10 O + 23.75 L + 1.25 X

Oligomer 14: 10 N + 10 C + 5 0 + 9.375 L + 0.625 X

Oligomer 15: 10 N + 20 C + 20 H + 32.5 L + 2.5 X

Oligomer 16: 10 N + 10 C + 10 H + 14.375 L + 0.625 X

Table 1: Yields and properties of oligo (ester-imides) with maleimide end groups

a) measured at 20 ° C with c = 2 g / 1 in CH ₂ C1 ₂ / trifluoroacetic acid (volume ratio 4: 1) b) DSC measurement, heating rate 20 ° C / min c) optical microscope, heating rate 10 ° C / min

Table 2: Yields and properties of oligoesters with maleimide end groups

Table 3: Yields and properties of oligoesters with norbornenedicarboximide end groups

Claims

claims

1. Cholesteric oligomers of formula I.

( _Z l _γl_) \ (AY ² -) \ (BY ³ -) \ Z ² n ' ^v ' q ^λ 'p (I)

wherein

n stands on average for a value from 0 to 1,

q stands on average for a value from 0.1 to 2,

p stands on average for a value from 1 to 20,

A represents a chiral group,

B represents a mesogenic group,

wherein

represents a chemical bond or a mono- or polysubstituted alkylene or arylene spacer; and

w represents a crosslinkable heterocyclic group.

2. Cholesteric oligomers according to claim 1, characterized in that W is selected from residues of the formula

wherein E represents a crosslinkable alkenylene group, and the radicals R can be the same or different and hydrogen or -CC alkyl, such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec .-Butyl or tert-butyl.

3. Cholesteric oligomers according to claim 2, characterized in that E for

stands in which the radicals R have the meaning given above.

4. Cholesteric oligomers according to claim 3, wherein the groups A are selected from chiral groups which are derived from aliphatic ethers or thioethers; araliphatic ethers or thioethers; .Amino acids, especially L-proline; Prolinol; Camphoric acid or lithocholic acid; Resin acids, in particular abietic and dehydroabietic acid; Sugars, especially pentoses and hexoses; Derive binaphthyl or biphenyl derivatives or from optically active glycols or diols;

the groups B are selected from if necessary by

Fluorine, chlorine, bromine, cyano, C 1 -C ₄ -alkyl, C 1 -C ₄ -alkoxy, hydroxy- or nitro-substituted, linear aliphatic, isocycloaliphatic, heterocycloaliphatic, isoaromatic or heteroaromatic groups or among compounds containing 2 to 4 such groups , linked by chemical bonds or via bridging elements, such as oxygen, sulfur, -CO-O-, -0- CO-0-, -CO-N (R) - or -N (R) -C0- contain and

W has the meaning given above; and Q represents a chemical bond or an arylene radical optionally substituted with one or more groups selected from C 1 -C ₄ -alkoxy, fluorine, chlorine, bromine, cyano, hydroxy or nitro, in particular a phenylene or naphthylene radical.

Cholesteric oligomers according to one of the preceding claims, wherein the groups A are selected independently of one another from groups of the formula

CH ₃ CH ₂ CH CH ₂ S CH ₂ CH ₂ -

being in the formulas above

for H, alkyl, alkoxy, alkylthio, halogen, COOR, OCOR,

CONHR or NHCOR stands,

R is C 1 -C ₄ alkyl or hydrogen and X is S, 0, N, CH ₂ or a single bond.

Cholesteric oligomers according to one of the preceding claims, wherein the groups B are selected independently of one another from groups of the formula

where each of the phenyl groups or the naphthyl group may have 1, 2 or 3 substituents which are independently selected from straight-chain or branched C 1 -C ₄ -alkyl, C,-C ₄ -alkoxy, fluorine, chlorine, bromine, cyano, hydroxy or Nitro, being in the formulas above

W represents NR, S, 0, (CH ₂ ) _g O (CH ₂ ) _h , (CH ₂ ) _m or 0- (CH ₂ ) _m -0,

G represents a single bond, 0 or S,

R represents alkyl or hydrogen,

m represents an integer from 1 to 15, and

g and h are independently integers from 0 to 10.

7. Cholesteric oligomers according to any one of the preceding claims, wherein

the groups A are selected independently of one another under groups of the formula

' in particular

(c) (e)

and - (CH ₂ ) _m -, in particular (a), (d) and / or (e), where (f)

m represents an integer from 4 to 12;

the groups Y independently of one another are -CO-O- or -0-CO-, and

stands for or.

8. Cholesteric oligomers according to one of the preceding claims, wherein

q represents 0.1 to 1,

p stands for 2 and

n stands for 1.

9. Cholesteric oligomers according to one of the preceding claims, which contain the groups A and B and Z in the molar ratio A / B / Z, from about 0.05 to 2 / about 1 to 30 / 0.5 to 5, in particular from about Contain 0.1 to 1 / about 4.5 to 20 / about 1.5 to 2.5 in condensed form.

10. Cholesteric oligomers according to one of the preceding claims, whose inherent viscosity is about 0.1 to 3 dl / g, in particular 0.1 to 1.5 dl / g, particularly preferably about 0.1 to 0.5 dl / g, measured at 20 ° C.

5

11. Cholesteric oligomers according to one of the preceding claims, whose glass transition temperature is in the range from about 80 to 300 ° C, in particular 90 to 200 ° C, particularly preferably about 90 to 140 ° C.

10

12. Cholesteric polymer network, obtainable by heating the cholesteric oligomers according to one of the preceding claims.

15 13. Cholesteric polymeric network according to claim 12, obtainable by heating at a temperature of about 200 to 350 ° C, in particular about 250 to 300 ° C.

14. A process for the preparation of cholesteric oligoesters according to one of claims 1 to 11, characterized in that free diols of the formula A- (OH) ₂ with activated dicarboxylic acids, in particular with dicarboxylic acid dichlorides of the formula B- (C0C1) ₂ and groups or residues of the formula Z-OH and optionally with free diols of the formula B- (OH) ₂ in an inert solvent, in particular in an inert aromatic solvent, particularly preferably 1-chloronaphthalene.

15. A process for the preparation of cholesteric oligocarbonates according to any one of claims 1 to 11, characterized in that free diols of the formulas A- (0H) ₂ and B- (OH) ₂ and groups or radicals of the formula Z-OH with phosgene or in particular condensed diphosgene.

35 16. Use of the cholesteric oligomers according to one of claims 1 to 11 as a surface coating material or for the production of pigments.

17. Single or multilayer pigments containing cholesteric 40 oligomers according to one of claims 1 to 11, or cholesteric polymeric networks according to claim 12 or 13.

18. Use of cholesteric polymeric networks according to claim 12 or 13, or of pigments according to claim 17, in

45 Vehicle and vehicle accessories sector, in the IT, leisure,

Sports and games sector, as optical components, such as polarizers or filters, in the cosmetics sector, in the textile, leather or jewelry, in the area of gifts, in writing utensils or on spectacle frames, in the construction sector, in the household sector, for all kinds of printed matter, for the production of paints and varnishes, for the counterfeiting of processing objects and for the coating of everyday objects or for painting vehicles.

19. Compositions containing at least one pigment according to claim 17.