Abstract: Oxymethylene polymers are obtained in a granular form by cooling a solution or dispersion of an oxymethylene polymer, the temperature of which solution or dispersion is above the sintering temperature of the oxymethylene polymer, to a temperature just below the sintering temperature of the oxymethylene polymer. As dissolving or dispersing agent as well as precipitating and cooling agent there is used a mixture of methanol and water having a methanol content of at least 75% by weight. The oxymethylene polymer obtained is suitable as engineering plastic for preparing moulded articles.

Abstract: Poly(acrylic acid) salts having specific structural characteristics, which salts are useful for combatting virus diseases.

Abstract: Granular oxymethylene polymers are prepared by cooling a solution or dispersion of an oxymethylene polymer, the temperature of the said solution or dispersion being above the sintering temperature of the oxymethylene polymer, to a temperature just below the said sintering temperature. As dissolving or dispersing agent there is used a mixture of methanol and water. The cooling of the said solution or dispersion is effected in two stages while using a liquid cooling agent or a cooling device. After precipitation the coarse-granular polymer is separated from the fine-granular portion. It is suitable as engineering plastic for preparing molded articles.

Abstract: Vinylene carbonate may be polymerized in bulk, in solution or in dispersion by means of free radical forming initiators. Suitable comonomers are vinyl compounds. The polymerization is carried out generally at a temperature of 40 to 170.degree. C. The dispersing agents used in the dispersion polymerization are organic compounds which are liquid under normal conditions and which do not dissolve vinylene carbonate. Homo- and copolymers of vinylene carbonate may be used as starting material for the preparation of homo- and copolymers of vinylene glycol.

Abstract: Oxymethylene polymers are prepared by polymerization of trioxane, optionally in the presence of comonomers, with the acid of a cationically active initiator. Suitable initiators are salt-like compounds, especially onium salts of Lewis acids. The initiator is used in the form of a solution in a cyclic carbonic acid ester present in a liquid phase. The oxymethylene polymers are thermoplastic and may be used as engineering materials.

Abstract: The invention provides thermoplastic molding compositions having improved properties. The compositions are composed of a mixture of from 99.999 to 99.9 wt.% of a linear polyoxymethylene and from 0.001 to 0.1 wt.% of a branched or cross-linked copolymer of trioxan with a multifunctionally reacting compound and optionally a monofunctionally reacting compound, or with a monofunctionally reacting compound and a branched or cross-linked polyether, or of a subsequently branched or cross-linked linear polyoxymethylene having functional groups in lateral or chain position.

Abstract: Oxymethylene polymers (POM) are obtained in granular form by cooling a POM solution or dispersion having a temperature above the sintering temperature of the POM in two stages to a temperature just below the said sintering temperature. The solvent or dispersion agent used is a mixture of methanol and water and the cooling agent is a methanol/water mixture which may contain POM suspended therein. The granular POM obtained is suitable as technical material for making shaped articles.

Abstract: Copolymers of trioxane with cyclic acetals may be prepared by copolymerization of the monomers in solid phase. For this purpose the monomers are first mixed homogeneously in a liquid phase with a catalyst, the mixture is then solidified by cooling and finally polymerized by heating, while maintaining it in a solid phase. The liquid phase mixture is cooled to solidify it immediately after mixing and prior to development of turbidity in the liquid mixture. Cooling can be effected, for example, on a chilled rotating roll. The moulding composition, obtained after having worked up the copolymer as usual, is a suitable material for the preparation of molded semi-finished products and finished articles.

Abstract: Oxymethylene copolymer having heat and hydrolysis resistant terminal groups is prepared by heating the polymers present in a liquid phase, whereby a thermal degradation of the unstable terminal groups takes place. The degradation is advantageously effected in the presence of a calcium or magnesium salt of an aliphatic carboxylic acid of low molecular weight. The oxymethylene copolymers are suitable as engineering plastic for preparing semi-finished products and finished products.

Abstract: Branched or crosslinked poly(exymethylenes) are suitable as nucleating agents for linear poly(oxymethylenes). For ameliorating the mechanical properties of shaped articles, being prepared of such moulding compositions which contain nucleating agents, high molecular weight polymers are used having a certain softening point, second order transition temperature and particle size, and which are blended into the moulding compositions. The modified moulding compositions can be processed in the thermoplastic state and are suitable as industrially useful materials for preparing semi-finished articles and finished products.

Abstract: Oxymethylene polymers are stabilized against the action of heat and oxygen by a stabilizer combination of an ester of a hydroxyl group containing araliphatic or aromatic carboxylic acid and an alkaline earth metal salt of an aliphatic, araliphatic or aromatic carboxylic acid. The efficiency of the stabilizer combination can be further improved by the addition of a costabilizer, especially a guanidine compound. The stabilized poly(oxymethylenes) are suitable for the manufacture of semifinished and finished articles.

Abstract: Polyacetals can be stabilized by means of a stabilizing composition, one of its components acting concurrently as a nucleating agent. Linear oxymethylene-polymers are used as polyacetals. The stabilizing composition consists of an urea-like compound and a phenolic anti-oxidation agent. Moulding compositions based on these stabilized polyacetals are appropriate for being worked-up in the thermoplastic state to shaped articles of all kinds.

Abstract: A moulding composition based on poly(oxymethylene) containing a substituted ureido-s-triazine as nucleating and stabilizing agent is an excellent engineering plastic useful for preparing shaped articles having stable dimensions and an exact size.