Abstract: The invention relates to a security marking whose level of proof against forgery is greater than that of known security markings, comprising liquid-crystalline material with chiral phase, wherein the security marking is imperceptible to the eye and the properties of the liquid-crystalline material with chiral phase can be detected with the aid of detection systems.

Abstract: The invention relates to a method of producing platelets, wherein a material to be processed into platelets is applied in a flowable or gaseous state to a substrate, consolidated, removed from the substrate, and subjected to a crushing or grinding process, wherein the material is applied to the substrate in succeeding layers such that after application, a lamina pack is present which, in cross section perpendicular to its surface, has individual laminae of a thickness of between 0.2-1000 &mgr;m, and said lamina pack, having been stripped from the substrate, is treated in such a way that the material disintegrates into individual laminae and the individual laminae are reduced in size to a particle size of 0.5-10000 &mgr;m.

Abstract: The invention relates to a security marking whose level of proof against forgery is greater than that of known security markings, comprising liquid-crystalline material with chiral phase, wherein the security marking is imperceptible to the eye and the properties of the liquid-crystalline material with chiral phase can be detected with the aid of detection systems.

Abstract: The invention relates to a security marking whose level of proof against forgery is increased relative to known security markings, comprising liquid-crystalline material with chiral phase, wherein present within the security marking are at least two liquid-crystalline materials with chiral phase which differ in at least one property selected from the group consisting of handedness, color and color flop and which are arranged in the form of a structured or unstructured marking or a multilayer marking or in the form of liquid-crystalline pigments in a liquid-crystalline matrix, or wherein there is at least one liquid-crystalline material with chiral phase whose reflection band has been broadened by means of special techniques, or wherein there is at least one liquid-crystalline material with chiral phase which has a defined three-dimensional arrangement.

Abstract: The invention relates to a method of producing platelets, wherein a material to be processed into platelets is applied in a flowable or gaseous state to a substrate, consolidated, removed from the substrate, and subjected to a crushing or grinding process, wherein the material is applied to the substrate in succeeding layers such that after application, a lamina pack is present which, in cross section perpendicular to its surface, has individual laminae of a thickness of between 0.2-1000 &mgr;m, and said lamina pack, having been stripped from the substrate, is treated in such a way that the material disintegrates into individual laminae and the individual laminae are reduced in size to a particle size of 0.5-10 000 &mgr;m.

Abstract: Crosslinkable LC organosiloxanes exhibiting excellent UV stability, contain units of the general formula 1 [RbMescSiO(4−b−c)/2]  (1) in which R are C1-C4-alkyl radicals, Mes is at least one group of the general formula 2 and, if desired, of the general formula 3, b has the value 0, 1 or 2, and c has the value 0, 1, 2, 3 or 4, with the proviso that the sum of the values of b and c is a maximum of 4, where the Mes groups of the general formulae 2 and 3 exhibit the following structure: —(CH2)p—(O)q—A—[B—A]r—E—F—VN  (2) —(CH2)m—(O)n—(A)t—Q—X  (3) in which A, B, Q, X, E, F, VN, m, p, n, q, t and r have the meanings given in claim 1, with the proviso that the LC organosiloxanes do not constitute a phenyl ester derivative of an aliphatic, aromatic or heteroaromatic carboxylic acids.

Abstract: The invention relates to mixtures containing pigments which comprise oriented three-dimensionally crosslinked substances having a liquid-crystalline structure with a chiral phase, and to the use of such mixtures. Pigment and matrix are matched to one another in such a way that on application of the mixture at different temperatures to a substrate, the lowest application temperature and highest application temperature differing by at least 10° C. and by not more than 150° C., there are no visually perceptible color differences of the pigmented paint on the substrate after drying.

Abstract: The invention relates to a process for the preparation of three-dimensionally crosslinked polymeric materials having a broad cholesteric reflection band, which comprises bringing polymeric materials having cholesteric properties and an extractable material content into contact with a solvent or solvent mixture.

Abstract: Materials of the formula I: ##STR1## in which R.sub.1, R.sub.2 and R.sub.3 in each case independently of one another can be identical or different and are a hydrogen atom, halogen atom, hydroxyl group, nitro group, cyano group or monovalent, optionally substituted organic radical; R.sub.4 is a hydrogen atom, halogen atom, nitro group, cyano group or monovalent, optionally substituted organic radical; and R.sub.5 can be identical or different and is a halogen atom, hydroxyl group, nitro group, cyano group or monovalent, optionally substituted organic radical.

Abstract: The invention relates to optical elements based on liquid-crystalline substances, and to a process for the production thereof. The optical elements based on liquid-crystalline substances are ones which exhibit no birefringence in a defined direction of incidence, optical elements in which no birefringence occurs perpendicularly to the surface being excepted. The process for preparing the optical elements comprises illuminating a liquid-crystalline substance with unpolarized light of suitable wavelength at a defined angle in such a way that, after illumination, the director of this substance is aligned parallel to the direction of the illuminating light on passing through said substance.

Abstract: The invention relates to optical elements based on helical liquid-crystalline substances, having reflection bands of linear-polarized light, and to a process for preparing the same. The optical elements of this invention contain only one optically effective component based on helical liquid-crystalline substances. They reflect light incident perpendicular to the surface in a linear-polarized manner parallel to the direction of incidence of the incident light. The process for preparing the optical elements comprises illuminating a helical liquid-crystalline substance which contains at least one photoisomerizable substance with linear-polarized light in such a manner that this substance is subsequently aligned so that it exhibits at least one reflection band of linear-polarized light on illumination. Suitable helical liquid-crystalline substances are in particular organopolysiloxanes. The optical elements are suitable, for example, for data storage.

Abstract: The invention relates to a process for the preparation of purple membrane containing bacteriorhodopsin, which process comprises obtaining, in a manner know per se, the cell membrane from halobacteria cells, and subjecting the material to gel filtration chromatography in order to isolate the purple membrane from the cell membrane.