| 摘要 |
<p>A composition comprises a major proportion of a vulcanizable butyl rubber having a viscosity average molecular weight in excess of 750,000 and a minor proportion of a hydrocarbon plasticizer oil having an iodine number of not more than 50 cg./g. The butyl rubber is produced by copolymerizing the isoolefin/multiolefin using as catalyst a solution of an aluminium halide, said solution having been purified of contaminating hydrocarbons and the catalyst concentration being maintained at 0,02 to 0,06%; the butyl rubber being subsequently milled and extruded with shearing stresses of less than 0,03 horsepower per pound per hour and at a temperature less than 350 DEG F. Specified plasticizers are paraffinic, naphthenic and aromatic oils. The composition may be compounded and vulcanized with the aid of ingredients selected from zinc oxide, sulphur, stearic acid, carbon black, silica, metal silicates, pigments, tellurium-dialkyl-dithiocarbamatespolyalkyl thiuram sulphides, mercapto-benzo, thiazole and benzo-thiazyl-disulphide. Applications specified are rubber tyres, conveyer and fan belts and rubber overshoes. Specifications 565,974, 589,353 and 664,366 are referred to.</p> |
