Bituminous compositions prepared with process treated vulcanized rubbers
AssigneePolyphalt L.L.C.
InventorZhi-Zhong Liang
Life of this patent
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Abstract
Stable rubberized bitumen concentrates are prepared by initially forming a mass comprising bitumen and crumb rubber particles in an amount of at least about 15 wt % of the mass with the crumb rubber being swollen in-situ, and applying shear and temperature conditions to the mass to dissociate the vulcanizate network of the rubber particles and to incorporate the digested vulcanizate into the bitumen. The stable rubberized bitumen concentrate is stable against sedimentation of rubber particles both following storage of the concentrate at about 320.degree. F. for 48 hours and dilution to a lower concentration in the ASTM solubility test.
Claims16
A stable rubberized bitumen concentrate, comprising:
- bitumen, and
- dissociated rubber vulcanizate network comprising at least about 15 wt % of said composition and incorporated into the bitumen to the extent that rubber particles in the composition do not sediment as determined by the Polymer Separation Test and upon dilution by bitumen to a lower concentration of dissociated rubber vulcanate network.
A method of forming a rubberized bitumen concentrate, which comprises:
- (A) providing a mass comprising:
- (a) bitumen, and
- (b) crumb rubber having a vulcanizate network in an initial amount of at least about 15 wt % of the mass, wherein said crumb rubber is swollen in-situ to form a vulcanizate network structure in the bitumen susceptible to dissociation of vulcanizate particles in a high shear field;
- and
- (B) subjecting said mass to sufficient shear and temperature conditions to effect dissociation of the vulcanizate network structure of the rubber particles to incorporate the vulcanizate into the bitumen to the extent that rubber particles in the composition do not sediment as determined by the Polymer Separation Test and upon dilution by bitumen to a lower concentration of dissociated rubber vulcanate network.
Dependencies are inferred from the claim text.