Abstract: A catalyst for the polymerization of 1-olefins is prepared by successively applying a chromate ester and a titanium ester to a carrier containing silicon dioxide, in the absence of an unsaturated polymerizable hydrocarbon, and activating with an aluminum-organic compound. In the manufacture of the catalyst no washing liquids are obtained from which metal compounds would have to be separated. In the presence of hydrogen the catalyst gives a high yield of polymers with broad molecular weight distribution and a small content of high molecular constituents. The films made therefrom are practically free from specks.

Abstract: A catalyst for the polymerization of 1-olefins is prepared by reacting a chromate ester fixed on a carrier selected from the group consisting of oxides of silicon, oxides of aluminum, and mixtures of said oxides, in the absence of an unsaturated polymerizable hydrocarbon, with an aluminum-organic compound and subsequently activating with aluminum-organic compound. No washing liquids that have to be worked up are obtained and the polymers, obtained in a high yield have a broad molecular weight distribution and contain only a small proportion of high molecular constituents. The films made therefrom are practically free from specks.

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.