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AssigneeBuilding Materials Investment Corporation
InventorsJames A. Svec, Keith Edward Stephens, Denis Muki Tibah
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The subject invention provides a method for producing essentially homogeneous asphalt compositions which are comprised of the asphalt, a block copolymer (such as a linear block copolymer or a radial block copolymer), and one or more additional desired additives. This method offers the advantage of being capable of attaining the essentially homogeneous asphalt composition in one pass procedure with a short residence time in the mixing equipment. This greatly reduces the thermal history to which heat sensitive asphalt additives, such as asphalt modification polymers, are exposed. It also simplifies the mixing procedure and can reduce the overall amount of energy required to attain the desired blend. In some case, it allows for the production on a commercial basis of asphalt compositions which would otherwise not be feasible, for instance the production of asphalt compositions which contain high levels of asphalt modifications polymers which are otherwise difficult to process.
A method for preparing an asphalt formulation in a continuous processor which comprises continuously feeding a base asphalt, a block copolymer, and optionally one or more additional ingredients, into a continuous processor having at least two co-rotating shafts, at least one feed zone, a driving zone, a mixing zone, and a discharge zone, wherein the asphalt is maintained in the continuous processor for a maximum residence time of about 20 minutes at a temperature which is above the softening point of the asphalt, and discharged from the discharge zone of the continuous processor as the asphalt formulation.
Dependencies are inferred from the claim text.