Magnetic storage medium

Claim 1

A process for the preparation of a magnetic recording and storage material having a flexible layer support carrying and having adhered thereto a layer comprised of a film-forming polymer composition acting as a binder for ferromagnetic particles dispersed in the layer, comprising the steps of dispersng ferromagnetic particles selected from the group consisting of CrO 2 and Fe 2 O 3 particles in a film-forming composition which contains at least 50 percent by weight of a copolymer wherein the copolymer used contains a polymerizable alkoxysilane compound which is based on the formula (R.sub.1 O).sub.3 Si--R.sub.2 in which R 1 represents an alkyl group containing 1 to 9 carbon atoms, and R 2 represents a group which contains a copolymerizable double bond, having a backbone chain and having attached to the backbone chain recurring side chain trialkoxysilane groups with one or more comonomers free of alkoxysilane groups selected from the group consisting of vinyl chloride, vinylidene chloride, vinyl acetate, vinyl ethers, acrylic acid esters, methacrylic acid esters, acrylonitrile and styrene; wherein the said copolymer based on the weight of the copolymer contains 3 to 10% by weight of trialkoxysilane units, said trialkoxysilane units being derived from trialkoxysilane compounds which contain copolymerizable carbon-carbon double bonds selected from the group consisting of vinyl trimethyloxysilane, vinyl triethoxysilane, vinyl tri-tert. butoxysilanemethacryloxy-propyl trimethoxysilane, and said film-forming composition contains from 0-50 percent by weight of a polymeric binder composition free from said alkoxysilane compounds, coating the dispersion of magnetizable material in the composition on a flexible support, and hardening the composition by cross-linking the side chains by a catalyzed reaction with a catalyst selected from the group of acid catalyzed-cross-linking catalysts and alkaline catalyzed-cross-linking catalysts.