Liquid-crystalline polymer blends comprising two or more cholesteric liquid-crystalline polymers or at least one nematic liquid-crystalline polymer and at least one cholesteric liquid-crystalline polymer. All hues can be produced specifically and in a reproducible manner by variation in the blend components and in the mixing ratio. The polymer blends are suitable as materials or as effect pigments.
A liquid crystal polyester resin composition which suppresses the formation of a blister caused by a heat treatment at a high temperature and has excellent moldability. This composition comprises (A) a liquid crystal polyester comprising at least two aromatic oxycarbonyl recurring units and (B) a liquid crystal polyester comprising at least two aromatic oxycarbonyl recurring units, at least one aromatic dioxy recurring unit and at least one aromatic dicarbonyl recurring unit. The weight ratio of the liquid crystal polyester (A) to the liquid crystal polyester (B) is 90/10 to 30/70.
A method for producing a liquid crystalline polyester comprising the steps of acylating phenolic hydroxyl groups of an aromatic diol, an aromatic hydroxycarboxylic acid, or an aromatic diol and aromatichydroxycarboxylic acid with a fatty anhydride to obtain an acylated substance, and trans-esterifying said acylated substance with an aromatic dicarboxylic acid, an aromatic hydroxycarboxylic acid, or an aromatic dicarboxylic acid and aromatic hydroxycarboxylic acid, wherein the acylation, the trans-esterification, or the acylation and trans-esterification is conducted in the presence of a heterocyclic organic base compound containing two or more nitrogen atoms.
Cholesteric liquid-crystalline polymers, especially cholesteric liquid-crystalline polyesters, polycarbonates or polyamides, are used as photostable UV screens in cosmetic and pharmaceutical preparations for protecting the human epidermis or hair against UV radiation, especially in the region from 280 to 450 nm.
A shading spacer for liquid crystal consisting of a cross-linked polymer particles containing a dyestuff which is fixed in said polymer particles by taking a dyestuff compound having a silyl group which can be hydrolyzed in said polymer particles having a silyl group which can be hydrolyzed when said polymer particles are cross-linked, is provided in the present invention. In said shading spacer, removal of dyestuff from said polymer particles is prevented.
Colorant composition consisting essentially of one or more cholesteric liquid-crystalline polymers having a pitch of the helical superstructure of between 760 nm and 500 .mu.m, and of at least one colorant which absorbs light in the visible wavelength range. Suitable colorants are organic or inorganic pigments or dyes. Coatings featuring such colorant compositions are notable for heat insulation properties.