Patent GB-689570-A (GB)
Title: Manufacture of polymeric products
IPC: C08F253/00
Filed: 1949-08-25
Abstract: Soluble, tacky products are made by copolymerizing in a latex of rubber, gutta percha or balata, (1) a hydrocarbon or chlorohydrocarbon having conjugated double bonds, and (2) an ester of the type <FORM:0689570/IV (a)/1> where R1 and R2 are hydrogen or halogen atoms or alkyl radicals, R3 is a hydrogen atom or an alkyl radical and R4 is an alkyl radical, at least one of R1, R2 and R3 being an alkyl radical.  Specified diolefinic compounds are butadiene, isoprene and chloroprene.  Suitable esters are alkyl methacrylates, the alkyl group containing not more than 4 carbon atoms, and methyl and ethyl crotonates.  The rubber may comprise 2 to 20 per cent by weight of the total of rubber, diolefin and ester, the ester monomer from 20 to 70 per cent and the diolefin from 10 to 60 per cent.  After vulcanizing, the products range from rubber-like (with not more than 50 per cent ester) to leathery and resin-like materials.  Polymerization is effected in the presence of a catalyst, e.g. hydrogen peroxide, an organic hydroperoxide, persulphates and perborates, and an emulsifying agent, e.g. a soap such as sodium oleate, and salts of sulphated and sulphonated long-chain aliphatic compounds. Stabilizers, e.g. gelatine, casein, glue and polyvinyl alcohol, a surface tension regulator, e.g. an aliphatic alcohol of 5 to 8 carbon atoms, and a buffer are preferably also present.  A redox system may be employed using as reducing agents sodium sulphite or thiosulphate or dextrose, and a copper or iron salt as promotor. Air should be displaced from the reaction vessel and, after polymerization, a stabilizer such as phenyl-beta-naphthylamine is added.  The latex, which may be concentrated by creaming, may be coagulated by acids or polyvalent metal salts.  The products are soluble in benzene and may be compounded with vulcanizing agents, fillers, &c., such as carbon black, sulphur, zinc oxide, mercaptobenzthiazole, polycoumarone resin and diphenylguanidine, and sheeted out and vulcanized.ALSO:Soluble, tacky products are made by copolymerising in a latex of rubber, gutta percha or balata, (1) a hydrocarbon or chlorohydrocarbon having conjugated double bonds, and (2) an ester of the type <FORM:0689570/V/1> where R1 and R2 are hydrogen or halogen atoms or alkyl radicals, R3 is a hydrogen atom or an alkyl radical and R4 is an alkyl radical, at least one of R1, R2 and R3 being an alkyl radical.  Specified diolefinic compounds are butadiene, isoprene and chloroprene.  Suitable esters are alkyl methacrylates, the alkyl group containing not more than 4 carbon atoms, and methyl and ethyl crotonates.  The rubber may comprise 2 to 20 per cent by weight of the total of rubber, diolefin and ester, the ester monomer from 20 to 70 per cent and the diolefin from 10 to 60 per cent.  After vulcanising, the products range from rubber-like (with not more than 50 per cent ester) to leathery and resin-like materials.  Polymerisation is effected in the presence of a peroxy catalyst which may be present in a redox system, an emulsifying agent, an emulsifying stabiliser, surface tension regulator and also preferably a buffer (see Group IV (a)).  After polymerisation, a stabiliser such as phenyl-beta-naphthylamine is added.  The latex, which may be concentrated by creaming, may be coagulated by acids or polyvalent metal salts.  The products are soluble in benzene and may be compounded with vulcanising agents, fillers, &c. such as carbon black, sulphur, zinc oxide, mercaptobenzthiazole, polycoumarone resin and diphenylguanidine, and sheeted out and vulcanised.