Patent ID: 6767939
Filing Date: 2004-07-27
Classification: C08L

Abstract:
A method for preparing asphalt and polymer compositions comprising:heating the asphalt in a stirred tank to a temperature sufficient to allow stirring of the asphalt in the tank, wherein said temperature is at least 330Â° F.; adding an elastomeric polymer to the tank in an amount not greater than twelve percent by weight of the total composition to form a mixture; adding a crosslinking composition to the composition; continue stirring and maintain the temperature in the tank for at least forty-five minutes, wherein the crosslinking composition comprises at least 0.08 percent by weight based on the asphalt of 2-mercaptobenzothiazole from 0.08 to 0.3 percent by weight based on the asphalt of elemental sulfur, at least 0.04 percent by weight based on the asphalt of zinc oxide, less than 0.01 percent by weight based on the asphalt of tetramethylthiuram disulfide, and less than 0.02 percent by weight based on the asphalt of stearic acid.