GB886884A - Improvements in rubberized blown asphalt and method for making same - Google Patents

Abstract

Rubberized asphaltic compositions, for use as fillers in road building, waterproofing or paper laminants where good low-temperature properties are desired, consist of an asphalt blown to a softening-point of from 80 DEG to 165 DEG F. and rubber solids (e.g. 0,1% to 10% by weight based on the weight of asphalt) such as neoprene, butadienestyrene copolymers or natural rubber. The compositions are produced by air blowing (e.g. at 400 DEG -450 DEG F.) an asphalt flux, such as derived from natural or cracked, straight-run or vacuum-reduced asphalts, and having a viscosity of from 40 to 300 SFS at 210 DEG F., in the absence of any catalyst, to the above mentioned softening-point, and interblending the resultant blown asphalt with the rubber by introducing it, preferably by injecting it, in the form of an aqueous latex, into a hot (e.g. 450 DEG -600 DEG F.) molten highly fluid body of the blown asphalt, preferably flowing at a constant rate in a confined stream, so that the latex-water is flashed into steam upon contact with the asphalt causing vigorous agitation, whereby the rubber is intimately dispersed, and causing a sudden lowering of the temperature of the resultant mixture to below that (but not below 325 DEG F., preferably 350 DEG -400 DEG F.) at which the rubber is deleteriously affected, prior to the mixture being discharged into an open vessel where the steam may escape. Specifications 886,883, 886,885 and U.S.A. Specifications 2,921,105 and 2,921,313 are referred to.ALSO:Rubberised asphaltic compositions, for use as fillers in road building, waterproofing or paper laminants where good low-temperature properties are desired, consist of an asphalt blown to a softening-point of from 80 DEG to 165 DEG F. and rubber solids (e.g. 0,1% to 10% by weight based on the weight of asphalt) such as neoprene, butadiene-styrene copolymers (GRS) or nuatral rubbers. The compositions are produced by air blowing (e.g. at 400 DEG -450 DEG F.) an asphalt flux, such as derived from natural or cracked, straight -run or vacuum-reduced asphalts, and having a viscosity of from 40 to 400 SFS at 210 DEG F., in the absence of any catalyst, to the above mentioned softening-point, and interblending the resultant blown asphalt with the rubber by introducing it, preferably by injecting it, in the form of an aqueous latex, into a hot (e.g. 450 DEG -600 DEG F.) molten highly fluid body of the blown asphalt, preferably flowing at a constant rate in a confined stream, so that the latex-water is flashed into steam upon contact with the asphalt causing vigorous agitation, whereby the rubber is intimately dispersed, and causing a sudden lowering of the temperature of the resultant mixture to below that (but not below 325 DEG F., preferably 350 DEG -400 DEG F.) at which the rubber is deleteriously affected, prior to the mixture being discharged into an open vessel where the steam may escape. Specifications 886,883, 886,885 and U.S.A. Specifications 2,921,105 and 2,921,313 are referred to.