Rubber composition for tires and pneumatic tire

Patent metadata

Field	Value
Publication number	US-10538647-B2
Application number	US-201816164203-A
Country	US
Kind code	B2
Filing date	Oct 18, 2018
Priority date	Oct 8, 2014
Publication date	Jan 21, 2020
Grant date	Jan 21, 2020

Abstract

The present invention aims to provide rubber compositions for tires that contain a natural rubber achieving a balanced improvement in abrasion resistance, breaking performance, and processability to achieve a balanced improvement in abrasion resistance, breaking performance, and processability, and also provide pneumatic tires containing such rubber compositions for tires. Included is a rubber composition for tires comprising a modified natural rubber prepared by treating natural rubber latex with a proteolytic enzyme, and then treating the treated natural rubber latex with a lipolytic enzyme and/or a phospholipid degrading enzyme. Also included is a rubber composition for tires, comprising a modified natural rubber prepared by centrifuging natural rubber latex to recover a latex fraction comprising latex particles having an average particle size of 0.25 μm or less.

First claim

The invention claimed is:

1. A pneumatic tire comprising a rubber composition wherein said rubber composition comprises a modified natural rubber, the modified natural rubber prepared by centrifuging natural rubber latex to recover a latex fraction comprising latex particles having an average particle size of 0.25 μm or less.

2. The pneumatic tire according to claim 1 ,
wherein the modified natural rubber is prepared by, after recovering the latex fraction by centrifugation:
treating the recovered latex fraction with at least one enzyme selected from the group consisting of a proteolytic enzyme, a lipolytic enzyme, and a phospholipid degrading enzyme.

3. The pneumatic tire according to claim 1 ,
wherein the modified natural rubber is prepared by, after recovering the latex fraction by centrifugation:
treating the recovered latex fraction with a proteolytic enzyme, and then treating the treated latex fraction with at least one of a lipolytic enzyme or a phospholipid degrading enzyme.

4. The pneumatic tire according to claim 1 ,
wherein the modified natural rubber has a nitrogen content of 0.30 mass % or less.

5. The pneumatic tire according to claim 1 ,
wherein the modified natural rubber has a phosphorus content of 200 ppm or less.

6. The pneumatic tire according to claim 1 ,
wherein the modified natural rubber has a gel content of 20 mass % or less.

7. The pneumatic tire according to claim 1 ,
wherein the modified natural rubber is prepared by further coagulating the resulting latex fraction with (1) an acid and (2) at least one of: (i) at least one salt selected from the group consisting of calcium salts, sodium salts, potassium salts, and ammonium salts of nitric acid, sulfuric acid, carbonic acid, phosphoric acid, hydrochloric acid, and formic acid; and (ii) a polymer flocculant.

8. A method of producing a pneumatic tire, comprising:
centrifuging natural rubber latex to recover a latex fraction comprising latex particles having an average particle size of 0.25 μm or less to produce a modified natural rubber, and
kneading the modified natural rubber.

Assignees

• Sumitomo Rubber Ind

Inventors

• Matsuura Ai
• Tarachiwin Lucksanaporn
• KUM-OURM Hathainat

Classifications

• B60C1/00

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

• C08C1/10

  by centrifugation · CPC title

• C08C1/02 Primary

  Chemical or physical treatment of rubber latex before or during concentration · CPC title

• C08L7/00 Primary

  Compositions of natural rubber · CPC title

• C08L15/00

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