RUBBER COMPOSITION FOR USE IN TIRES

• US 20140155520A1
• Filed: 07/13/2012
• Published: 06/05/2014
• Est. Priority Date: 07/14/2011
• Status: Active Grant

• Current Assignee: Yokohama Rubber Company Limited
• Original Assignee: Yokohama Rubber Company Limited
• Inventors: Takeda, Shinya
• Granted Patent: US 9,260,600 B2
• Time in Patent Office: Days
• US Class Current: 523/156
• CPC Class Codes: B60C 1/00 Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
• CPC Class Codes: B60C 1/0016 Compositions of the tread
• CPC Class Codes: C08C 19/22 Incorporating nitrogen atoms into the molecule
• CPC Class Codes: C08K 2201/006 Additives being defined by their surface area
• CPC Class Codes: C08K 2201/014 Additives containing two or more different additives of the same subgroup in C08K
• CPC Class Codes: C08K 3/04 Carbon
• CPC Class Codes: C08K 3/36 Silica
• CPC Class Codes: C08L 15/00 Compositions of rubber derivatives C08L11/00, C08L13/00 take precedence
• CPC Class Codes: C08L 47/00 Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds; Compositions of derivatives of such polymers C08L45/00 takes precedence; of conjugated diene rubbers C08L9/00 - C08L21/00
• CPC Class Codes: C08L 9/00 Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
• CPC Class Codes: C08L 9/06 Copolymers with styrene
• CPC Class Codes: C08L 91/00 Compositions of oils, fats or waxes; Compositions of derivatives thereof
• CPC Class Codes: C08L 93/00 Compositions of natural resins; Compositions of derivatives thereof of polysaccharides C08L1/00 - C08L5/00; of natural rubber C08L7/00
• CPC Class Codes: Y02T 10/86 Optimisation of rolling resistance, e.g. weight reduction

Abstract

A rubber composition comprises from 2 to 50 parts by weight of an aromatic modified terpene resin having a softening point of ≧100° C., and two types of silica, a silica X and a silica Y, at a total quantity of 60 to 130 parts by weight relative to 100 parts by weight of a diene rubber containing from 5 to 50 weight % of a modified S-SBR having a vinyl content of not lower than 60 weight %. A functional group in the modified S-SBR reacts with a silanol group, a proportion of silica relative to the total quantity of a reinforcing filler containing the silica and carbon black is not lower than 85 weight %, a nitrogen specific surface area of the silica X is not lower than 140 m²/g, and a nitrogen specific surface area of the silica Y is not lower than 100 m²/g but lower than 140 m²/g.

Claims

1. A rubber composition for use in tires comprising from 2 to 50 parts by weight of an aromatic modified terpene resin having a softening point of 100°

C. or higher, and two types of silica, including a silica X and a silica Y, at a total quantity of 60 to 130 parts by weight relative to 100 parts by weight of a diene rubber containing from 5 to 50 weight % of a solution polymerization-produced terminally modified styrene-butadiene rubber (a modified S-SBR) having a vinyl unit content of not lower than 60 weight %, wherein a functional group in the modified S-SBR reacts with a silanol group on a surface of the silica, a proportion of silica relative to a total quantity of a reinforcing filler containing the silica and carbon black is not lower than 85 weight %, a nitrogen specific surface area of the silica X is not lower than 140 m2/g, a nitrogen specific surface area of the silica Y is not lower than 100 m2/g but lower than 140 m2/g, and where blending quantities of the silica X and the silica Y relative to 100 parts by weight of the diene rubber are deemed to be x parts by weight and y parts by weight respectively, the relationship x/7<

y≦

x is satisfied.

2. The rubber composition for use in tires according to claim 1, wherein the functional group in the modified S-SBR is a hydroxyl group.

3. The rubber composition for use in tires according to claim 1, wherein the functional group in the modified S-SBR is an amino group.

4. A pneumatic tire that uses the rubber composition for use in tires according to claim 1.

5. The rubber composition for use in tires according to claim 1, wherein the modified S-SBR has a vinyl unit content of from 60 to 80 weight %.

6. The rubber composition for use in tires according to claim 1, wherein the functional group is at least one type selected from a hydroxyl group-containing polyorganosiloxane structure, an alkoxysilyl group, a hydroxyl group, an aldehyde group, a carboxyl group, an amino group, an imino group, an epoxy group, an amide group, a thiol group, or an ether group.

7. The rubber composition for use in tires according to claim 6, wherein the functional group is the hydroxyl group or the amino group.

8. The rubber composition for use in tires according to claim 1, comprising from 10 to 30 weight % of the modified S-SBR relative to 100 weight % of the diene rubber.

9. The rubber composition for use in tires according to claim 1, wherein the diene rubber contains from 50 to 95 weight % of diene rubbers other than the modified S-SBR.

10. The rubber composition for use in tires according to claim 1, wherein the diene rubber contains from 70 to 90 weight % of diene rubbers other than the modified S-SBR.

11. The rubber composition for use in tires according to claim 10, wherein the diene rubbers other than the modified S-SBR include one or more diene rubbers selected from the group consisting of:

natural rubbers, butadiene rubbers, emulsion polymerization-produced styrene-butadiene rubbers, unmodified solution polymerization-produced styrene-butadiene rubbers, solution polymerization-produced terminally modified styrene-butadiene rubbers other than the modified S-SBR, and brominated isobutylene/p-methylstyrene copolymer rubbers.

12. The rubber composition for use in tires according to claim 1, wherein the aromatic modified terpene resin has a softening point of from 100°

C. to 130°

C.

13. The rubber composition for use in tires according to claim 1, comprising from 5 to 50 parts by weight of the aromatic modified terpene resin relative to 100 parts by weight of the diene rubber.

14. The rubber composition for use in tires according to claim 1, wherein the nitrogen specific surface area of the silica X is from 150 m2/g to 230 m2/g.

15. The rubber composition for use in tires according to claim 1, wherein the nitrogen specific surface area of the silica X is from 150 m2/g to 185 m2/g.

16. The rubber composition for use in tires according to claim 1, wherein the nitrogen specific surface area of the silica Y is higher than 100 m2/g and not higher than 130 m2/g.

17. The rubber composition for use in tires according to claim 1, wherein the nitrogen specific surface area of the silica Y is from 105 m2/g to 130 m2/g.

18. The rubber composition for use in tires according to claim 1, comprising a total quantity of 80 to 130 parts by weight of the silica relative to 100 parts by weight of the diene rubber.

19. The rubber composition for use in tires according to claim 1, wherein the proportion of the silica relative to the total quantity of the reinforcing filler containing the silica and carbon black is from 90 to 100 weight %.

20. The rubber composition for use in tires according to claim 1, further comprising a sulfur-containing silane coupling agent in an amount of from 50 to 12 weight % of the silica.