Patent ID: 7417082
Filing Date: 2008-08-26
Classification: C08K,C08L

Abstract:
1. A method for making a modified asphalt binder composition, comprising the steps of: a. providing neat asphalt in an appropriate vessel; b. heating the neat asphalt to a temperature of between about 120° C. and about 200° C.; c. adding to the neat asphalt a first modifying ingredient selected from the group consisting of crumb rubber, at least one acid, and one or more synthetic polymers; d. mixing the asphalt and the first modifying ingredient with one of a high shear mixer or a low shear mixer for a period of between about 5 minutes and about 10 hours; e. adding a second modifying ingredient selected from the group consisting of crumb rubber, at least one acid, one or more synthetic polymers, and a cross-linking agent, wherein the second modifying ingredient is a different type of modifying ingredient than the first modifying ingredient, and the second modifying ingredient may be a cross-linking agent only if the first modifying ingredient is crumb rubber; f. mixing the second modifying ingredient and the asphalt with one of a high shear mixer or a low shear mixer for a period of between about 5 minutes and about 10 hours g. adding a third modifying ingredient selected from the group consisting of crumb rubber, at least one acid one or more synthetic polymers and a cross-linking agent, wherein the third modifying ingredient is a different type of modifying ingredient than the first modifying ingredient and the second modifying ingredient, and the third modifying ingredient may be a cross-linking agent only if the first or the second modifying ingredient is crumb rubber; h. agitating the third modifying ingredient and the asphalt with one of a high shear mixer or a low shear mixer for a period of between about 5 minutes and about 48 hours; i. adding a fourth modifying ingredient selected from the group consisting of at least one acid one or more synthetic polymers and a cross-linking agent, wherein the third modifying ingredient is a different type of modifying ingredient than the first modifying ingredient, the second modifying ingredient, and the third modifying ingredient; and j. agitating the fourth modifying ingredient and the asphalt with a low shear mixer for a period of between about 5 minutes and about 48 hours.