Abstract: The present invention relates to a method for preparing an industrial asphalt comprising (1) heating an asphalt flux to a temperature which is within the range of about 400° F. (204° C.) to 550° F. (288° C.) to produce a hot asphalt flux, (2) sparging an oxygen containing gas through the hot asphalt flux for a period of time which is sufficient to increase the softening point of the asphalt flux to a value of at least 100° F. (38° C.), to produce an underblown asphalt composition; and (3) mixing a sufficient amount of a polyphosphoric acid throughout the underblown asphalt composition while the underblown asphalt composition is maintained at a temperature which is within the range of 200° F. (93° C.) to 550° F. (288° C.) to attain a softening point which is within the range of 185° F. (85° C.) to 250° F. (121° C.) and a penetration value of at least 15 dmm at 77° F. (25° C.) to produce the industrial asphalt.

Abstract: This invention is based upon the discovery that a small amount of lime can be incorporated into industrial asphalt to greatly improve its resistance to oxidative hardening cracking and low temperature thermal cracking. The incorporation of a small amount of lime into industrial asphalt accordingly results in products made therewith offering improved service life. For instance, roofing shingles made with such asphalt that contains a small amount of lime will be more resistant to cracking and failure in both hot and cold weather climates. The subject invention more specifically discloses an asphalt roofing shingle having an upper surface and an underside, said asphalt roofing shingle being comprised of a fiber mat which is coated with an asphalt composition, wherein the upper surface of the asphalt roofing shingle includes a layer of roofing granules, wherein the asphalt composition has a softening point which is within the range of 185° F. (85° C.) to 250° F. (121° C.

Abstract: The present invention relates to a method for preparing an industrial asphalt comprising (1) heating an asphalt flux to a temperature which is within the range of about 400° F. (204° C.) to 550° F. (288° C.) to produce a hot asphalt flux, (2) sparging an oxygen containing gas through the hot asphalt flux for a period of time which is sufficient to increase the softening point of the asphalt flux to a value of at least 100° F. (38° C.), to produce an underblown asphalt composition; and (3) mixing a sufficient amount of a polyphosphoric acid throughout the underblown asphalt composition while the underblown asphalt composition is maintained at a temperature which is within the range of 200° F. (93° C.) to 550° F. (288° C.) to attain a softening point which is within the range of 185° F. (85° C.) to 250° F. (121° C.) and a penetration value of at least 15 dmm at 770° F. (25° C.) to produce the industrial asphalt.