Patent ID: 7241821

Claim:
A method for preparing a polymer-modified, vulcanized asphalt composition comprising i) treating an asphalt cement under mild oxidizing conditions sufficient to provide a change in viscosity as measured at 140° C. from 100 to 500 poises per hour of said asphalt cement, ii) adding from about 1 wt. % to about 10 wt. % of a polymer based on weight of said asphalt cement, iii) vulcanizing the polymer-containing asphalt cement, wherein said asphalt cement is selected from the group consisting of natural asphalts and synthetic asphalts, the polymer comprising a linear block copolymer added in amounts ranging from about 1 wt. % to about 5 wt. %; iv) maintaining said asphalt cement at temperatures ranging from 100° to 400° C. and injecting air to said asphalt cement at about 1 to about 10 SCFH, for 0.1 to 5 hours, and wherein said vulcanizing is carried out by adding about 0.01 wt. % to about 1 wt. % sulfur based on said asphalt cement content to provide a sulfur-containing mixture and maintaining the resulting mixture at a temperature ranging from about 150° to about 240° C. for about 0.5 to about 2 hours.