Process for preparing bitumen-polymer compositions
AssigneeElf Union
InventorsPaul Maldonado, Jean Mas, Trung K. Phung
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Abstract
The present invention is related to a novel process for preparing bitumen-polymer compositions. These compositions contain block copolymers comprising diene and styrene groups. The compositions present excellent mechanical properties even at low temperatures.
Claims18
A process for obtaining a bitumen-polymer composition which consists in contacting with each other, at a temperature between 130.degree. and 230.degree. C., 80 to 98% by weight of a bitumen exhibiting a penetration value between 30 and 220, and 2 to 20% by weight of a block copolymer, with an average molecular weight between 30,000 and 300,000 having the theoretical formula S.sub.x - B.sub.y in which:
- S corresponds to the styrene structure groups,
- B corresponds to the conjugated diene structure groups,
- x and y are integers,
- stirring the obtained mixture for at least two hours, then adding 0.1 to 3% by weight of elemental sulphur with respect to the bitumen and maintaining the mixture thus obtained under agitation for at least 20 minutes.
A bitumen-polymer composition comprising 80 to 98% by weight of a bitumen having a penetration value between 30 and 220, and 2 to 20% by weight of a block copolymer, with an average molecular weight between 30,000 and 300,000 having the theoretical formula S.sub.x - B.sub.y in which:
- S corresponds to the styrene structure groups,
- B corresponds to the conjugated diene structure groups and
- x and y are integers, and 0.1 to 3% by weight of sulphur.
Dependencies are inferred from the claim text.