| 摘要 |
The invention relates to a polyvinyl chloride-based composition with high heat and impact resistance and to a process for preparing the same. According to the invention, the composition comprises 80 parts of polyvinyl chloride, 20 parts of nitrile rubber of the NBR 28-45-type, 4 parts of tribasic lead sulphate, 1 part of dibasic lead stearate, 0.3 parts of stearin, 0.08 parts of sulphur and 0.6 parts of vulcanization accelerator selected from dicumyl peroxide, tetraethyl-thiuram or tetramethyl-thiuram disulphide, cyclohexyl-benzthiazyl sulphamide, diphenyl-guanidine, benztriazole disulphide, phenyl-naphthyl amine and N-isopropyl-N'-phenyl-p-phenylene diamine, the parts being expressed by weight. The claimed process for preparing the composition consists in mixing polyvinyl chloride with nitrile rubber, lead-based stabilizers and a system for cross-linking the resulting mixture, said system comprising sulphur and a compound selected from dicumyle peroxide, tetraethyl-thiuram or tetramethyl-thiuram disulphide, cyclohexyl-benzthiazyl sulphamide, diphenyl-guanidine, benztriazole disulphide, phenyl-naphthyl amine and N-isopropyl-N'-phenyl-p-phenylene diamine at a temperature of 165 C, for 15 min., then pressing the resulting mixture at a temperature of 170 C and a pressure of 170 atm., for 3 min.
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