Waste plastic additive for asphalt
AssigneeBP Corporation North America Inc.
InventorsJohn M. Forgac, Ashok S. Muzumdar, Arun K. Singhania, April J. Swanson
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Abstract
The present invention provides an improved polymer additive which may be used to increase the high temperature viscosity of an asphalt, without deleteriously affecting the low-temperature viscosity of the asphalt. The polymer additive may also be used to improve the stiffness of certain asphalts. The polymer additive is produced from readily available polymer blends by a thermal process. The invention additionally provides an improved polymer modified asphalt. In its preferred embodiments, the invention also provides an environmentally acceptable method for recycle of post consumer carpet and bottles.
Claims9
A liquefied polymer additive composition, useful for improving the properties of asphalt, which polymer additive is produced by a process of:
- (a) providing a predominantly solid polymer feedstock comprising at least 5 weight percent polypropylene having a molecular weight in the range of about 1,000 to about 50,000;
- and
- (b) thermally, treating the polymer feedstock in the presence of an inert gas purge, which is substantially oxygen free, at a pressure of about 0.1 to about 45 atmospheres and a temperature in the range of about 250° C. to about 600° C. for a time period in the range of about 1 minute to about 48 hours to produce the polymer additive.
A process for manufacturing a polymer additive, useful for improving the properties of an asphalt, comprising the steps of:
- (a) providing a predominantly solid polymer feedstock comprising at least 5 weight percent polypropylene having a molecular weight in the range of about 1,000 to about 50,000;
- and
- (b) thermally, treating the polymer feedstock in the presence of an inert gas purge, which is substantially oxygen free, at a pressure of about 0.1 to about 45 atmospheres and a temperature in the range of about 250° C. to about 600° C. for a time period in the range of about 1 minute to about 48 hours to produce the polymer additive.
Dependencies are inferred from the claim text.