Asphalt composition

DETAILED DESCRIPTION The asphalt employed in this invention can be any of the well known bituminous substances derived from a number of materials such as, for example, petroleum, shale oil, coal tar and the like.
Asphalt is a thick, viscous mixture of compounds such as, for example, paraffinic, cycloaliphatic and aromatic hydrocarbons and lesser amounts of heterocyclic compounds containing sulfur, nitrogen or oxygen.
Although asphalt can be obtained from natural sources it is primarily derived as the residue of petroleum distillation (e.
g.
the bottom product of a vacuum distillation of a topped crude).
Although this invention is not limited thereto, it is presently preferred that the asphalt have a penetration (ASTM D5) at 77.
degree.
C.
ranging from about 50 to about 250 and more preferably from about 110 to about 130.
The alkadiene-vinylarene copolymers suitable for use in this invention are derived from alkadiene monomers and vinyl-substituted aromatic monomers.
The copolymers can be linear or branched.
They can be random copolymers or block copolymers.
At the option of the practitioner the copolymers can be partially or substantially hydrogenated.
Thermoplastic block copolymers are presently preferred.
Suitable alkadiene monomers used to produce the alkadiene-vinylarene copolymers are the unsaturated hydrocarbons containing at least two double bonds.
The alkadiene monomers may be straight-chained (e.
g.
1,3-butadiene) or cyclic (e.
g.
cyclopentadiene) but straight-chained is preferred.
It is also preferred that the alkadiene monomer be conjugated (e.
g.
1,3-butadiene) as opposed to unconjugated (e.
g.
1,2-butadiene).
Although the alkadiene monomer can contain any number of carbon atoms it is contemplated that the alkadiene monomer will ordinarily in the practice of this invention contain from 4 to 12 carbon atoms.
Those containing from 4 to 8 carbon atoms are especially preferred.
Examples of suitable alkadiene monomers include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, piperylene, phenyl-1,3-butadiene, 1,3-pentadiene, 2-ethyl-1,3-pentadiene, 1,3-hexadiene, 2-methyl-1,3-undecadiene, 2-methyl-3-isopropyl-1,3-butadiene, and the like