Rubber composition for tire

Patent metadata

Field	Value
Publication number	US-10377883-B2
Application number	US-201515128406-A
Country	US
Kind code	B2
Filing date	Feb 19, 2015
Priority date	Mar 31, 2014
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

The present invention provides a rubber composition for a tire having improved workability and abrasion resistance. A rubber composition for a tire according to the present invention comprises: a polybutadiene which has: (A) a Mooney viscosity (ML1+4,100° C.) being 43 or more; (B) a ratio (Tcp/ML1+4,100° C.) of 5 wt % toluene solution viscosity (Tcp) to Mooney viscosity (ML1+4,100° C.) being 0.9 to 2.3; (C) a stress relaxation time (T80) being 10.0 to 40.0 seconds, which is a time until a torque is attenuated by 80% when the torque at the end of ML1+4,100° C. measurement is 100%; and (D) a molecular weight distribution (Mw/Mn) being 2.50 to 4.00; another rubber (ii); and a rubber reinforcing material (iii).

First claim

What is claimed is:

1. A rubber composition for a tire, comprising:
a polybutadiene (i) which has:
(A) a Mooney viscosity (ML 1+4,100° C. ) being 43 to 70;
(B) a ratio (Tcp/ML 1+4,100° C. ) of 5 wt % toluene solution viscosity (Tcp) to Mooney viscosity (ML 1+4,100° C. ) being 0.9 to 1.7;
(C) a stress relaxation time (T80) being 10.0 to 40.0 seconds, which is a time until a torque is attenuated by 80% when the torque at the end of ML 1+4,100° C. measurement is 100%; and
(D) a molecular weight distribution (Mw/Mn) being 2.50 to 4.00;

a second rubber (ii); and
a rubber reinforcing material (iii).

2. The rubber composition for a tire according to claim 1 , wherein 1 to 100 parts by weight of the rubber reinforcing material (iii) is compounded with respect to 100 parts by weight of the rubber component (i)+(ii) which consists of 5 to 90 parts by weight of the polybutadiene (i) and 95 to 10 parts by weight of the second rubber (ii).

3. The rubber composition for a tire according to claim 1 , wherein the polybutadiene (i) further has:
(E) a weight average molecular weight (Mw) being 40.0×10 4 to 75.0×10 4 , and
(F) a ratio of cis-structure to cis-structure, trans-structure and vinyl-structure in microstructural analysis being 98 mol % or less.

4. The rubber composition for a tire according to claim 1 , wherein the polybutadiene (i) is produced by using a cobalt catalyst.

5. The rubber composition for a tire according to claim 1 , comprising a styrene butadiene rubber as the second rubber (ii).

6. The rubber composition for a tire according to claim 1 , comprising a natural rubber or an isoprene rubber as the second rubber (ii).

7. The rubber composition for a tire according to claim 2 , wherein the polybutadiene (i) further has:
(E) a weight average molecular weight (Mw) being 40.0×10 4 to 75.0×10 4 , and
(F) a ratio of cis-structure to cis-structure, trans-structure and vinyl-structure in microstructural analysis being 98 mol % or less.

8. The rubber composition for a tire according to claim 2 , wherein the polybutadiene (i) is produced by using a cobalt catalyst.

9. The rubber composition for a tire according to claim 3 , wherein the polybutadiene (i) is produced by using a cobalt catalyst.

10. The rubber composition for a tire according to claim 2 , comprising a styrene butadiene rubber as the second rubber (ii).

11. The rubber composition for a tire according to claim 3 , comprising a styrene butadiene rubber as the second rubber (ii).

12. The rubber composition for a tire according to claim 4 , comprising a styrene butadiene rubber as the second rubber (ii).

13. The rubber composition for a tire according to claim 2 , comprising a natural rubber or an isoprene rubber as the second rubber (ii).

14. The rubber composition for a tire according to claim 3 , comprising a natural rubber or an isoprene rubber as the second rubber (ii).

15. The rubber composition for a tire according to claim 4 , comprising a natural rubber or an isoprene rubber as the second rubber (ii).

16. The rubber composition for a tire according to claim 5 , comprising a natural rubber or an isoprene rubber as the second rubber (ii).

Assignees

• Ube Industries
• Sumitomo Rubber Ind

Inventors

• AMBE Mitsuharu
• KANOU Yuuto
• Shoda Takeshi
• Mabuchi Takahiro
• Haba Toshifumi

Classifications

• C08L9/06 Primary

  Copolymers with styrene · CPC title

• C08L9/00

  Compositions of homopolymers or copolymers of conjugated diene hydrocarbons · CPC title

• C08F36/06

  Butadiene · CPC title

• C08F4/7096

  Cobalt or compounds thereof · CPC title

• B60C1/00

  Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition · CPC title