| 摘要 |
Chlorinated polyethylene containing carboxylic ester groups in which the alcohol residue is aliphatic and ethylenically unsaturated and contains 3 to 20 carbon atoms, the proportion of chlorine atoms being sufficient to render the polymer elastomeric and the proportion of ester groups being sufficient to render it sulphurcurable may be prepared by chlorocarboxylating with oxalyl chloride or phosgene a solution of polyethylene and then adding, preferably in excess, the unsaturated alcohol. In the chlorocarboxylating the solvent employed for the polyethylene should be substantially inert to chlorine, free radical catalysts may be used and suitable temperatures are 100 DEG to 200 DEG C. After esterification with the unsaturated alcohol, the esterified carboxylated polyethylene can be isolated by precipitation from solution. Alcohols mentioned are allyl, oleyl, crotyl, o -undecylenyl and 9-eicosenyl alcohols and 1-butene 3-ol; 3-hexene-1-ol; 1-heptene-4-ol and 2-methyl-2-heptene-6-ol. The esterified carboxylated chlorinated polyethylene may be cured with organic peroxides or sulphur. In the examples: (1) linear polyethylene dissolved in 1,2,4-trichlorobenzene is treated with oxalyl chloride and benzoyl peroxide. After adding 1,11 - azobisisobutyronitrile, chlorine is added until the chlorine content has reached 31%. The mixture is then treated with allyl alcohol to produce the chlorinated polyethylene of the invention and (2) a solution of chlorocarboxylated polyethylene prepared as in Example 1 except that it contains 35.9% of chlorine, is treated with oleyl alcohol. |
