Pneumatic tire, studless tire, method for manufacturing pneumatic tire, and method for manufacturing studless tire

Patent metadata

Field	Value
Publication number	US-9862814-B2
Application number	US-201414888285-A
Country	US
Kind code	B2
Filing date	May 12, 2014
Priority date	May 23, 2013
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

Provided are pneumatic tires or studless winter tires that achieve a balanced improvement in fuel economy, reinforcing properties (flex crack growth resistance, abrasion resistance, tensile strength, adhesive strength, resistance to air permeation), grip performance (wet-grip performance, performance on snow and ice), handling stability, and heat aging resistance, and methods for producing such a pneumatic tire or studless winter tire. The present invention relates to a pneumatic tire including at least one component selected from the group consisting of a sidewall, a base tread, a bead apex, a clinch apex, an innerliner, and an undertread, each of which is formed from a rubber composition that contains a highly purified, modified natural rubber whose pH is adjusted to 2 to 7, and carbon black and/or a white filler.

First claim

The invention claimed is:

1. A pneumatic tire, comprising at least one component selected from the group consisting of a sidewall, a base tread, a bead apex, a clinch apex, an innerliner, and an undertread, each of which is formed from a rubber composition that comprises
a modified natural rubber whose pH is adjusted to 2 to 7, wherein the modified natural rubber has a phosphorus content of 200 ppm or less, and
at least one of carbon black or a white filler.

2. A pneumatic tire, comprising at least one of a breaker topping or a ply topping, each of which is formed from a rubber composition that comprises
a modified natural rubber whose pH is adjusted to 2 to 7, wherein the modified natural rubber has a phosphorus content of 200 ppm or less, and
carbon black.

3. A pneumatic tire, comprising a tread, the tread being formed from a rubber composition that comprises
a modified natural rubber whose pH is adjusted to 2 to 7, wherein the modified natural rubber has a phosphorus content of 200 ppm or less,
styrene-butadiene rubber, and
a white filler.

4. The pneumatic tire according to claim 1 , 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.

5. The pneumatic tire according to claim 1 , 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.

6. The pneumatic tire according to claim 1 , 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.

7. The pneumatic tire according to claim 1 , wherein the modified natural rubber has a nitrogen content of 0.15% by mass or less.

8. The pneumatic tire according to claim 1 , wherein the modified natural rubber has a heat aging resistance index of 75 to 120%, the heat aging resistance index being defined by the following equation based on Mooney viscosities ML (1+4) at 130° C. measured in conformity 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.

9. A method for producing the pneumatic tire according to claim 1 , comprising:
step 1-1 of saponifying natural rubber latex;
step 1-2 of coagulating the saponified natural rubber latex obtained in step 1-1, treating the coagulated rubber with a basic compound, and washing the treated coagulated rubber;
step 1-3 of treating the washed coagulated rubber with an acidic compound to adjust the pH of the entire rubber to 2 to 7; and
step 1-4 of kneading the modified natural rubber obtained in step 1-3.

10. A method for producing the pneumatic tire according to claim 1 , comprising:
step 2-1 of deproteinizing natural rubber latex;
step 2-2 of coagulating the deproteinized natural rubber latex obtained in step 2-1, and washing the coagulated rubber;
step 2-3 of treating the washed coagulated rubber with an acidic compound to adjust the pH of the entire rubber to 2 to 7; and
step 2-4 of kneading the modified natural rubber obtained in step 2-3.

11. A studless winter tire, formed from a rubber composition that comprises
a modified natural rubber whose pH is adjusted to 2 to 7, wherein the modified natural rubber has a phosphorus content of 200 ppm or less, and
at least one of carbon black or a white filler.

12. The studless winter tire according to claim 11 , 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.

13. The studless winter tire according to claim 11 , 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.

14. The studless winter tire according to claim 11 , 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.

Assignees

• Sumitomo Rubber Ind

Inventors

• Sakaki Toshiaki
• YOKOYAMA Yuka

Classifications

• B60C1/00 Primary

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

• C08C1/04

  Purifying; Deproteinising · CPC title

• C08K3/04

  Carbon · CPC title

• C08L9/06

  Copolymers with styrene · CPC title

• C08L19/006

  Rubber characterised by functional groups, e.g. telechelic diene polymers · CPC title