Patent GB-1526297-A (GB)
Title: Silylated organic polymers and organic-organopolysiloxane block copolymers
IPC: C08F293/00
Filed: 1975-12-16
Abstract: 1526297 Silylated organic polymers and organic-organo-polysiloxane block copolymers SWS SILICONES CORP 16 Dec 1975 [16 Dec 1974] 51425/75 Headings C3S C3T and C3P A silylated organic polymer of the general formula where Y is an organic polymeric radical, M is an alkali metal atom and the remaining valencies of the silicon atom are satisfied by polymeric organic radicals and optionally, by monomeric hydrocarbon radicals, may be prepared by a process which comprises causing an alkali-metal-terminated organic polymer to react with a vinyl-silane of the formula:- where R is a monovalent hydrocarbon radical free of aliphatic unsaturation, X is a halogen atom, an acyloxy group free of aliphatic unsaturation, a hydrocarbonoxy group free of aliphatic unsaturation, a phosphato, sulphonyl, sulphito, sulphato or perchlorato group, a is 1, 2 or 3, b is 0, 1 or 2 and a+b does not exceed 3, optionally in the presence of an aprotic solvent: the said organic polymer is generally an alkali metal terminated hydrocarbon polymer which may be prepared by polymerizing an olefinically unsaturated monomer in the presence of an alkali metal-carbanion-producing substance, e.g. an alkali metal or an organo-alkali metal compound, and an aprotic solvent. Suitable monomers include olefines, vinyl-aromatic compounds, unsaturated esters or nitriles. The silylated organic polymer may be further reacted with an olefinically unsaturated monomer and/or an olefinically unsaturated organosilane and/or a cyclic organopolysiloxane preferably of the formula where n is at least 3, the latter reaction with the cyclic siloxane producing an organic-organosiloxane block copolymer. The said block copolymer may be further reacted with an olefinically unsaturated monomer and/or an olefinically unsaturated organosilane. Any of the above silylated organic polymers or block copolymers may be reacted with a compound selected from carboxylic acids and anhydrides, inorganic acids, alcohols and silanes which have at least one functional group selected from halogen, acyloxy, phosphato, sulfato, hydrocarbonoxy and perchlorato radicals or with a carbanion-terminated organic polymer. The polymers and block copolymers may be vulcanized by heating in the presence of a vulcanizing agent, e.g. sulphur, disulphides, alkylphenol sulphides, p-dinitrosobenzene, sulphur dichloride or tetramethyl thiuram disulphide, or organic peroxy compounds; or by using high energy radiation; or they may be combined with a silane or siloxane crosslinking agent, e.g. methyltriacetoxysilane or methylhydrogensiloxane to form RTV or heat-vulcanizable compositions. Curing may be accelerated using catalysts selected from titanates, tin salts of carboxylic acids, and Pt compounds and complexes. In the examples silylated organic polymers and block co-polymers are prepared by polymerizing t-butylstyrene styrene or isoprene in the presence of n-butyl lithium or 9-fluorenyl-sodium in heptane and tetrahydrofuran and reacting the product with methylvinyldichlorosilane. Then either (1) acetic acid is added to the resultant product to produce a silylated organic polymer; or (2) hexamethylcyclotrisiloxane or octamethylcyclotetrasiloxane and benzene are added to the reaction mixture followed by acetic acid to produce a block copolymer.