Road paving binders

Abstract

This invention provides for novel road paving binder compositions and the method of making them. One embodiment is a road paving binder composition of a storage stable blend of a sulfonated, unhydrogenated random copolymer of styrene and butadiene having a sulfonation level of from 1 to 100 meq S0.sub.3 H/100 g of polymer and a sulfonated asphalt. Another is a method of making a storage stable polymer modified asphalt composition by combining a sulfonated unhydrogenated random styrene butadiene copolymer having a sulfonation level of from about 1 to 100 meq S0.sub.3 H per 100 g of polymer and a sulfonated asphalt at a temperature of at least about 180.degree. C. to produce a storage stable polymer modified asphalt. Yet another is a method of making a storage stable polymer modified asphalt by combining a sulfonated unhydrogenated random styrene and butadiene copolymer having a sulfonation level of from about 1 to 100 meq S0.sub.3 H/100 g of polymer, and unsulfonated asphalt and a basic neutralizing agent at a temperature of from about 170.degree. C. to 185.degree. C. to produce a storage stable polymer modified asphalt. Still another is a method for making a storage stable road paving composition by cosulfonation of a blend of unhydrogenated random styrene-butadiene copolymer and an asphalt at 180.degree.-210.degree. C. The novel road paving asphaltic compositions have enhanced viscoelasticity and storage stability. The compositions can be used as binders in road paving applications. Sulfonated copolymers of random styrene-isoprene may be substituted for the sulfonated copolymers of styrene-butadiene herein.

Dependencies are inferred from the claim text.