Rubber composition for use in tire treads

Patent metadata

Field	Value
Publication number	US-9790306-B2
Application number	US-201314424435-A
Country	US
Kind code	B2
Filing date	Aug 27, 2013
Priority date	Aug 30, 2012
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

A rubber composition for use in tire treads comprising from 60 to 130 parts by weight of silica per 100 parts by weight of diene rubber containing not less than 50% by weight of hydroxyl group-containing modified styrene butadiene rubber, in which the weight ratio of oil to filler containing the silica is not greater than 0.25, and a silane coupling agent having a mercapto group and an Si—O bond is compounded in an amount from 4 to 15% by weight of the silica content, and diethylene glycol is compounded in an amount from 1 to 6% by weight of the silica content.

First claim

The invention claimed is:

1. A rubber composition for use in tire treads comprising:
from 60 to 130 parts by weight of silica per 100 parts by weight of diene rubber containing not less than 50% by weight of hydroxyl group-containing modified styrene butadiene rubber,
wherein:
a weight ratio of oil with respect to filler containing the silica is not greater than 0.25,
a silane coupling agent having a mercapto group and an Si—O bond is compounded in an amount from 4 to 15% by weight of the silica content,
diethylene glycol is compounded in an amount from 1 to 6% by weight of the silica content;
the silane coupling agent having a mercapto group and an Si—O bond is a mercaptosilane compound represented by general formula (2) below, or a copolymer having the structures of general formulas (3) and (4) below, or a polysiloxane having an average composition formula represented by general formula (5) below:

 (wherein R 3 , R 4 , and R 5 are mutually independently selected from hydrogen, alkyl groups having from 1 to 8 carbons, alkoxy groups having from 1 to 8 carbons, linear polyether groups having a chain length of from 4 to 30, and aryl groups having from 6 to 30 carbons, and, at least one is the alkoxy group and at least one is the linear polyether group, and R 6 is an alkylene group having from 1 to 30 carbons);

 (wherein R 7 and R 8 may form a ring structure, and R 7 is selected from hydrogen, halogen, or alkyl groups or alkylene groups having from 1 to 30 carbons, alkenyl groups or alkenylene groups having from 2 to 30 carbons, alkynyl groups or alkynylene groups having from 2 to 30 carbons, and groups in which a terminal of the above alkyl group or alkenyl group is substituted with a hydroxyl group or carboxyl group; R 8 is an alkylene group having from 1 to 30 carbons, an alkenylene group having from 2 to 30 carbons, or an alkynylene group having from 2 to 30 carbons; x is an integer of 1 or greater);

 (wherein R 9 and R 10 may form a ring structure, and R 9 is selected from a hydrogen, halogen, or alkyl groups or alkylene groups having from 1 to 30 carbons, alkenyl groups or alkenylene groups having from 2 to 30 carbons, alkynyl groups or alkynylene groups having from 2 to 30 carbons, and groups in which a terminal of the above alkyl group or alkenyl group is substituted with a hydroxyl group or carboxyl group; R 10 is an alkylene group having from 1 to 30 carbons, an alkenylene group having from 2 to 30 carbons, or an alkynylene group having from 2 to 30 carbons; y is an integer of 1 or greater);
(A) a (B) b (C) c (D) d (R 11 ) e SiO (4-2a-b-c-d-e)/2    (5)

 (wherein A is a bivalent organic group containing a sulfide group; B is a monovalent hydrocarbon group having from 5 to 10 carbons; C is a hydrolyzable group; D is an organic group containing a mercapto group; R 11 is a monovalent hydrocarbon group having from 1 to 4 carbons; and a to e satisfy relationships 0≦a <1, 0≦b<a, 0<c<3, 0<d<1, 0≦e<2, and 0<2a+b+c+d+e<4; however, at least one of a and b is not 0).

2. The rubber composition for tire treads according to claim 1 , wherein bis(3-triethoxysilylpropyl) tetrasulfide is compounded in an amount from 2 to 5% by weight of the silica content.

3. The rubber composition for tire treads according to claim 2 , wherein a vulcanization retarder represented by general formula (1) below is compounded in an amount greater than 0 parts by weight and not greater than 1.0 parts by weight per 100 parts by weight of the diene rubber:

(wherein R 1 is a linear hydrocarbon group, alicyclic hydrocarbon group or aromatic hydrocarbon group having from 1 to 10 carbons, R 2 is a hydrogen atom, a linear hydrocarbon group or alkoxy group having from 1 to 4 carbons, or a branched hydrocarbon group or alkoxy group having from 3 to 4 carbons).

4. The rubber composition for use in tire treads according to claim 3 , wherein the diene rubber contains greater than 0% by weight and not greater than 45% by weight of natural rubber.

5. The rubber composition for tire treads according to claim 1 , wherein a vulcanization retarder represented by general formula (1) below is compounded in an amount greater than 0 parts by weight and not greater than 1.0 parts by weight per 100 parts by weight of the diene rubber:

(wherein R 1 is a linear hydrocarbon group, alicyclic hydrocarbon group or aromatic hydrocarbon group having from 1 to 10 carbons, R 2 is a hydrogen atom, a linear hydrocarbon group or alkoxy group having from 1 to 4 carbons, or a branched hydrocarbon group or alkoxy group having from 3 to 4 carbons).

6. The rubber composition for use in tire treads according to claim 5 , wherein the diene rubber contains greater than 0% by weight and not greater than 45% by weight of natural rubber.

7. The rubber composition for use in tire treads according to claim 2 , wherein the diene rubber contains greater than 0% by weight and not greater than 45% by weight of natural rubber.

8. The rubber composition for use in tire treads according to claim 1 , wherein the diene rubber contains greater than 0% by weight and not greater than 45% by weight of natural rubber.

9. A pneumatic tire comprising the rubber composition for use in tire treads described in claim 3 .

10. A pneumatic tire comprising the rubber composition for use in tire treads described in claim 2 .

11. A pneumatic tire comprising the rubber composition for use in tire treads described in claim 1 .

Assignees

• Yokohama Rubber Co Ltd

Inventors

• Sato Masaki
• Mihara Satoshi
• Akahori Yayoi
• Tsukishima Shin
• Naka Ayumi

Classifications

• C08K5/548

  containing sulfur {(C08K5/5477 takes precedence)} · CPC title

• C08F236/10 Primary

  with vinyl-aromatic monomers · CPC title

• C08K3/36

  Silica · CPC title

• C08L7/00

  Compositions of natural rubber · CPC title

• C08L15/00 Primary

  Compositions of rubber derivatives (C08L11/00, C08L13/00 take precedence) · CPC title