Abstract: Delayed-release tablets are formed by incorporating hemicellulose and a matrix-forming adjuvant which does not disintegrate in a pharmaceutical dosage form containing the active substance or substances, preferably as a coated tablet or dragee.

Abstract: Pure cyanuric acid is prepared from crude or waste melamine by introducing the melamine into 70 to 80% strength sulfuric acid at room temperature and heating the reaction mixture to 150.degree. to 190.degree. C., the water introduced with the sulfuric acid being distilled off during the heating period.

Abstract: Novel spirocyclic boron compounds of the formula ##STR1## in which R.sub.1 and R.sub.2 are various halogen containing organic :radicals and Z.sup.+ is a hydrogen ion, an equivalent of an alkaline-earth metal ion, a guanidinium ion or alkylammonium ion as flame retarding agents in various plastics, such as polyurethanes, epoxide resins and polyesters.

Abstract: Foamed plastics with improved combustion characteristics are produced by condensing an aqueous solution of formaldehyde-urea and/or melamine precondensates with polyisocyanates and optionally a polyol in the presence of an acid catalyst, being present in an amount of 1 part by weight per at least 20 parts by weight of precondensate, whereby this catalyst is added to the isocyanate before mixing with the precondensate or to the mixture of isocyanate and precondensate, but separately from the precondensate.

Abstract: Melon is prepared by heating, in the solid form, preferably as granules, a mixture of dicyandiamide and melamine, or a mixture of one or both thereof with urea and/or biuret and/or triuret and/or guanidine carbonate at a temperature from 450.degree. to 600.degree. C.

Abstract: Guanidine carbonate is isolated from dilute aqueous solutions containing guanidine, urea, pyrolysis products of urea, ammonia and carbon dioxide, by evaporation of the solution at a temperature of 80.degree. to 130.degree. C until a guanidine carbonate content of 20g/l and a pyrolysis products content of not more than 28g/l at 80.degree. C or not more than 128.degree. g/l at 30.degree. C is achieved, without exceeding a heating time of 6 hours at the upper temperature limit, separation of the precipitated pyrolysis products, subsequent cooling to not more than 45.degree. C, addition of ammonia to an ammonia content of 15 to 30 % by weight and separation of the precipitated guanidine carbonate.

Abstract: Process for obtaining guanidine carbonate from aqueous solutions in which it is present with urea and its pyrolysis products as well as ammonia and carbon dioxide, which comprises heating the aqueous solution to a temperature of at most 80.degree.C at atmospheric pressure, evaporating the resulting solution, which contains an amount of carbon dioxide equal to the guanidine content, until it is saturated with urea, separating the solid precipitate, suspending the mother liquor in liquid ammonia and separating the resulting guanidine carbonate.