Patent ID: 7985787
Filing Date: 2011-07-26
Classification: C08K,C08L

Abstract:
1. A method for producing an improved bitumen comprising the steps of: (a) providing a first quantity of bitumen or mixture of bitumens heated to a temperature of between about 100° C. to about 230° C.; (b) adding to the first quantity of bitumen or mixture of bitumens polyphosphoric acid and maintaining the resulting mixture at a temperature of between about 100° C. to about 230° C. while stirring for a period of at least about 10 minutes; (c) providing a second quantity of bitumen or mixture of bitumens heated to a temperature of between about 100° C. to about 230° C.; (d) adding to the second quantity of bitumen or mixture of bitumens at least one sulfur cross-linkable elastomer and at least one sulfur-donor coupling agent in an amount capable of providing an amount of free sulfur representing between 0.1% and 20% of the weight of the sulfur cross-linkable elastomer while maintaining the temperature of the bitumen at between 100° C. and 230° C. with stirring for a period of at least about 10 minutes (e) combining a sufficient amount of the first quantity of bitumen with a sufficient quantity of the second quantity of bitumen to obtain a final bitumen product having polyphosphoric acid in an amount of between about 0.005% to 5% by weight of the weight of the final bitumen product and at least one sulfur cross-linkable elastomer in an amount of between 0.5% to 20% by weight of the weight of the final bitumen product, and wherein the amount of polyphosphoric acid added to the first quantity of bitumen and the amount of the at least one sulfur cross-linkable elastomer added to the second quantity of bitumen are selected to achieve the desired concentrations of polyphosphoric acid and sulfur-crosslinkable elastomer in the final bitumen product.