A new method is proposed for the production of plane-parallel platelets,
comprising the steps a) vapor-deposition, at a pressure below atmospheric
pressure, of a separating agent onto a carrier to produce a separating
agent layer, b) vapor-deposition, at a pressure below atmospheric
pressure, of at least one product layer onto the separating agent layer,
c) dissolution of the separating agent layer in a solvent and production
of a suspension in which the at least one product layer is present in the
form of plane-parallel platelets, in which method the separating agent is
selected from the group consisting of anthracene, anthraquinone,
acetamidophenol, acetylsalicylic acid, camphoric anhydride,
benzimidazole, benzene-1,2,4-tricarboxylic acid,
biphenyl-2,2-dicarboxylic acid, bis(4-hydroxyphenyl)-sulfone,
dihydroxyanthraquinone, hydantoin, 3-hydroxybenzoic acid,
8-hydroxyquinoline-5-sulfonic acid monohydrate, 4-hydroxycoumarin,
7-hydroxycoumarin, 3-hydroxynaphthalene-2-carboxylic acid, isophthalic
acid, 4,4-methylene-bis-3-hydroxynaphthalene-2-carboxylic acid,
naphthalene-1,8-dicarboxylic anhydride, phthalimide and its potassium
salt, phenol-phthalein, phenothiazine, saccharin and its salts,
tetraphenylmethane, triphenylene, triphenylmethanol, and also mixtures of
at least two of those substances. Separating agents that have been found
to be especially suitable are aromatic compounds having at least one
benzene ring. The present invention relates also to the use of the
plane-parallel platelets thereby produced and also to the products
obtainable using such methods.