Rubber composition for tires and pneumatic tire

Patent metadata

Field	Value
Publication number	US-2016297954-A1
Application number	US-201415100506-A
Country	US
Kind code	A1
Filing date	Nov 27, 2014
Priority date	Dec 26, 2013
Publication date	Oct 13, 2016
Grant date	—

Abstract

Provided are a rubber composition for tires that shows a balanced improvement in properties such as fuel economy, processability, heat aging resistance, abrasion resistance, wet-grip performance, performance on snow and ice, and handling stability, and a pneumatic tire formed from the rubber composition. The present invention relates to a rubber composition for tires, containing: a highly purified, modified natural rubber having a pH adjusted to 2-7; carbon black and/or a white filler; and a styrene-butadiene rubber having a styrene content of 30% by mass or more, and also relates to a pneumatic tire formed from the rubber composition.

First claim

1 - 13 . (canceled)

14 . A rubber composition for tires, comprising:
a modified natural rubber having a phosphorus content of 200 ppm or less and further having a pH adjusted to 2 to 7; at least one of carbon black or a white filler; and a styrene-butadiene rubber having a styrene content of 30% by mass or more.

15 . The rubber composition for tires according to claim 14 ,
wherein the modified natural rubber is obtained by removing non-rubber components in natural rubber, followed by treatment with an acidic compound, and the modified natural rubber has a pH of 2 to 7.

16 . The rubber composition for tires according to claim 14 ,
wherein the modified natural rubber is obtained by washing a saponified natural rubber latex and treating the washed saponified natural rubber latex with an acidic compound, and the modified natural rubber has a pH of 2 to 7.

17 . The rubber composition for tires according to claim 14 ,
wherein the modified natural rubber is obtained by washing a deproteinized natural rubber latex and treating the washed deproteinized natural rubber latex with an acidic compound, and the modified natural rubber has a pH of 2 to 7.

18 . The rubber composition for tires according to claim 14 ,
wherein the modified natural rubber has a nitrogen content of 0.15% by mass or less.

19 . The rubber composition for tires according to claim 14 ,
wherein the pH is determined by cutting the modified natural rubber into pieces at most 2 mm square on each side, immersing the pieces in distilled water, irradiating the immersed pieces with microwaves for extraction at 90° C. for 15 minutes, and measuring the resulting immersion water with a pH meter.

20 . The rubber composition for tires according to claim 14 ,
wherein the modified natural rubber has a heat aging resistance index of 75 to 120%, the heat aging resistance index being defined by the equation below based on Mooney viscosities ML (1+4) at 130° C. measured in accordance with JIS K 6300:2001-1,
Heat aging resistance index (%)=(Mooney viscosity of the modified natural rubber measured after heat treatment at 80° C. for 18 hours)/(Mooney viscosity of the modified natural rubber before the heat treatment)×100.

21 . The rubber composition for tires according to claim 14 ,
wherein the white filler is silica.

22 . The rubber composition for tires according to claim 14 ,
wherein the modified natural rubber is prepared without mastication.

23 . The rubber composition for tires according to claim 14 ,
wherein the styrene-butadiene rubber is modified with a polar group having an affinity for silica.

24 . The rubber composition for tires according to claim 14 ,
wherein the styrene-butadiene rubber has a weight average molecular weight of 2.5×10 5 to 2.5×10 6 .

25 . A pneumatic tire, formed from the rubber composition for tires according to claim 14 .

Assignees

• Sumitomo Rubber Ind

Inventors

• Sakaki Toshiaki
• Nakamura Masanobu
• YOKOYAMA Yuka

Classifications

• C08C1/04

  Purifying; Deproteinising · CPC title

• B60C11/005

  with cap and base layers · CPC title

• C08L9/06

  Copolymers with styrene · CPC title

• B60C1/00

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

• C08K3/04

  Carbon · CPC title