Patent ID: 6025418
Filing Date: 2000-02-15
Classification: C08K,C08L,C10C

Abstract:
A process for preparing bitumen/polymer compositions having improved properties, characterized in that it comprises the steps of:(i) bringing a bitumen of penetration between 20 and 320 and an elastomeric polymer into mixing contact at a temperature of between 140 and 180.degree. C., the said elastomeric polymer being a styrene/conjugated diene block copolymer comprising from 1 to 20% by weight of the bitumen/polymer mixture;(ii) as soon as the elastomeric polymer is incorporated into the bitumen, introducing into the mixture from 0.01 to 0.1% by weight, based on the weight of the bitumen/elastomeric polymer mixture, vulcanizing agents comprising (a) a sulphur-containing derivative selected from the group of derivatives having the formulae I and II ##STR10## in which R.sub.1 and R.sub.2 are like or different alkyl radicals having from 1 to 4 carbon atoms, or, combined together, form a radical having the formula ##STR11## and wherein M is a metal selected from zinc, barium or copper, and (b) elemental sulphur, such that the sulphur-containing derivative: elemental sulphur ratio is between 20:80 and 80:20;and(iii) introducing into the bitumen/elastomeric polymer mixture, simultaneously with the vulcanizing agents, an alkaline compound which is soluble in the bitumen.