| 摘要 |
Vulcanized elastomers are prepared by heating a synthetic rubber polymer, having groups which under the vulcanization conditions employed are hydrolysable to carboxylic acid groups, with a sulphur curative or an organic peroxide and with an oxide or hydroxide of an alkaline earth metal or lead monoxide in the presence of a neutral or basic organic hydroxy compound. The rubber polymer may be a copolymer of butadiene and styrene together with an alkyl or aralkyl ester of an a ,b -ethylenically unsaturated carboxylic acid, e.g. an alkyl sorbate or acrylate (including cyanoalkyl acrylates) or methacrylate, or an itaconate; minor proportions of maleate and fumarate esters may also be present; terpolymers of acrylonitrile with butadiene and an ester such as methyl acrylate may also be used. Curing agents specified are dicumyl peroxide and a mixture of sulphur and N-cyclohexyl-2-benzthiazyl sulphenamide. The oxides and hydroxides used are CaO, Ca(OH)2, MgO and PbO; ZnO may additionally be present. The preferred hydroxy compound is glycerol; others mentioned are ethylene glycol, diethylene glycol, 1,2- and 1,3-propylene glycols, 1,4- and 2,3-butylene glycols, 2,4-hexylene glycol, sucrose and starch. Optional ingredients which may be present during vulcanization include reinforcing fillers, e.g. carbon black, extending oils, other polymers, processing aids such as stearic acid and mineral oil, and antioxidants, e.g. phenyl-b -naphthylamine, N,N1-diphenyl phenylenediamine, p,p1-dimethoxydiphenylamine, isopropylaminodiphenylamine and 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline. Examples illustrate the vulcanization of butadiene-styrene-methyl acrylate and butadiene-methyl methacrylate copolymers.
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