Process for preparing bitumen-polymer compositions

• US 4,145,322 A
• Filed: 12/28/1977
• Issued: 03/20/1979
• Est. Priority Date: 12/28/1976
• Status: Expired due to Term

• Current Assignee: KOCH Enterprises Incorporated
• Original Assignee: ELF Union
• Inventors: Maldonado, Paul, Mas, Jean, Phung, Trung K.
• Primary Examiner(s): Marquis, Melvyn I.
• Application Number:
  US05/865,245
• Time in Patent Office: 447 Days
• Field of Search: 260/28.5 AS
• US Class Current: 524/68
• CPC Class Codes: C08K 3/06 Sulfur
• CPC Class Codes: C08L 53/00 Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 53/02 of vinyl-aromatic monomers and conjugated dienes
• CPC Class Codes: C08L 95/00 Compositions of bituminous materials, e.g. asphalt, tar, pitch
• CPC Class Codes: Y10T 428/31815 Of bituminous or tarry residue

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.

Claims

1. A process for obtaining a bitumen-polymer composition which consists in contacting with each other, at a temperature between 130°

and 230°

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_x - B_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.

2. A process according to claim 1, characterized in that the block copolymer has a molecular weight between 70,000 and 200,000.

3. A process according to either claim 1, characterized in that the block copolymer is di-block copolymer.

4. A process according to either claim 1, characterized in that the block copolymer is a tri-sequential or tri- or polyblock copolymer.

5. A process according to claim 1, characterized in that the block copolymer contains 10 to 60% by weight of styrene groups.

6. A process according to claim 5, characterized in that the block copolymer contains 15 to 30% by weight of styrene groups.

7. A process according to claim 1 characterized in that the conjugated diene is butadiene, isoprene or mixtures thereof.

8. A process according to claim 1, characterized in that the conjugated diene is isoprene.

9. Bitumen-polymer compositions characterized in that they are obtained according to the process of claim 1.

10. 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_x - B_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.

11. A composition according to claim 10 wherein the block copolymer has a molecular weight between 70,000 and 200,000.

12. A composition according to claim 10 wherein the block copolymer is a di-, tri- or polyblock copolymer.

13. A composition according to claim 12 wherein the molecular weight of the tri-block or polyblock copolymer is at least 120,000.

14. A composition according to claim 12 wherein the molecular weight of the di-block copolymer is between 30,000 and 120,000.

15. A composition according to claim 10 wherein the block copolymer contains 10 to 60% by weight of styrene groups.

16. A composition according to claim 10 wherein the block copolymer is a butadiene-styrene di-block copolymer with a butadiene/styrene ratio of 70/25, by weight.

17. A composition according to claim 10 wherein the block copolymer is a tri-block butadiene-styrene copolymer with a butadiene/styrene ratio of 70/30, by weight.

18. A composition according to claim 10 wherein the block copolymer is a di-block styrene-isoprene copolymer with an isoprene/styrene ratio of 83/17, by weight.