| 摘要 |
A tacky self-sealing rubbery composition suitable for use as a puncture-sealing agent when adhered to a layer of puncturable vulcanized rubbery material comprises at least one polyacrylate as a homopolymer of an alkyl acrylate having a C2 to C8 alkyl group, or a copolymer of mixtures thereof or of one or more such acrylates with less than 50 per cent of at least one other mono-olefinic monomer, or blended or copolymerized mixtures thereof. The sealant may include 10-90 per cent natural and synthetic rubbers, such as polyisobutylene, polychloroprene, and polymers and copolymers of open-chain conjugated dienes having 4 to 8 carbon atoms, e.g. butadienes, or mixtures thereof, and the mono-olefinic monomers may be halogen-substituted ethylenes, substituted alkyl acrylates and methacrylates, acrylic and methacrylic acids and their sodium salts and nitriles, vinyl ethers, styrene and halogen and alkyl derivatives thereof, tetrahydrofurfuryl acrylate, N-tert.-butyl acrylamide, N - vinyl - 2 - pyrrollidone, 2 - vinylpyridine, vinyl triethoxysilane, dichloromaleic anhydride, crotonic acid, or 2-butene-1 : 4-diol. If the sealant contains rubbers it should be treated to effect vulcanization. For this purpose the sealant mixes may contain agents such as sulphur with or without triethyl trimethylenetriamine, triethylenetetramine, paraquinone dioxime with or without red lead, sodium metasilicate pentahydrate, sodium hydroxide, magnesium oxide, zinc oxide, zinc peroxide, phenyl hydrazine, tetramethyl thiuram disulphide, 2-mercaptobenzthiazole, N - cyclohexyl - 2 - mercaptobenzthiazole sulphinamide, while the sealant may also contain plasticisers such as dibutyl phthalate and high molecular weight polyethers, as well as substances such as furnace carbon black, black iron oxide, silica, calcium silicate, clay, silicon monoxide, rosin, hydrogenated rosin, zinc stearate, stearic acid, processing oils, wool grease, and antioxidants if diene rubbers are used. Polybutyl acrylate is produced by coagulation of a latex formed by agitation at 50 DEG C. of an aqueous mixture of the monomer, potassium persulphate, sodium pyrophpsphate and salts of a homologous series of substituted aromatic sulphonic acids, and polymerized sodium salts of alkaryl and aralkyl sulphonic acids. A copolymer of ethyl acrylate and b -chlorethyl vinyl ether and a tetrapolymer of butyl acrylate, b -chloroethyl vinyl ether, acrylic acid, and methacrylic acid may be formed similarly. Specification 648,976, [Group XXXIV], is referred to. |
