Patent ID: 7402619

Claim:
A method for preparing bitumen/elastomeric polymer compositions comprising: a. heating the bitumen in a stirred tank to a temperature of between 220 and 430° F.; b. adding the elastomeric polymer to the tank in an amount of between 2 and 30 weight percent, to form a mixture of bitumen and elastomeric polymer; c. adding 0.01 to 5 weight percent of a cross-linking composition to the mixture and continuing stirring while maintaining the temperature of the mixture at between 275 and 430° F. for a time period of between 20 and 120 minutes; wherein said cross-linking composition comprises: a. 5 to 50 percent by weight of elemental sulfur: b. 0.5 to 10 percent by weight of a sulfur-containing derivative selected from the group consisting of compounds having the formula where R 1 and R 2 are like or different alky radicals having 1 to 4 carbon atoms and wherein M is selected from the group consisting of zinc, barium, copper, cadmium and thallium; c. 5 to 50 percent by weight of a sulfur activator selected from zinc compounds; d. 5 to 50 percent by weight of a solubilizing agent selected from fatty acids and fatty acid derivatives; and e. 10 to 85 percent by weight of a polymeric carrier, said cross-linking composition having a zinc content of at least 2 weight percent, based on the total weight of the cross-linking composition and a zinc to sulfur content weight ratio of 0.5:1 to 2:1.