Rubber composition

Patent metadata

Field	Value
Publication number	US-11267954-B2
Application number	US-201816485244-A
Country	US
Kind code	B2
Filing date	Feb 14, 2018
Priority date	Feb 15, 2017
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

A rubber composition including 100 parts by mass of a diene rubber containing natural rubber, and blended with from 40 to 80 parts by mass of carbon black, cobalt neodecanoate borate represented by the following Chemical Formula (1), a phenolic resin, a curing agent, sulfur, and a vulcanization accelerator, wherein the carbon black has DBP oil absorption of from 50×10−5 to 80×10−5 m3/kg, and iodine adsorption of from 100 to 150 g/kg, and a vulcanized rubber has characteristics of a dynamic storage modulus (E′) at a dynamic strain of 2% and at 20° C. of 8 MPa or more, a tangent loss (tan δ) at 60° C. of 0.20 or less, and the number of times of repetition until fracture is caused in a constant strain fatigue test at a strain of 60% and at 400 rpm of 45,000 or more.

First claim

The invention claimed is:

1. A rubber composition comprising: 100 parts by mass of a diene rubber containing natural rubber and blended with from 40 to 80 parts by mass of carbon black; cobalt neodecanoate borate represented by Chemical Formula (1) present in an amount from 0.3 to 1.5 parts by mass; a phenolic resin present in amount of 0.5 parts by mass or more and less than 3.0 parts by mass; a methylene donor curing agent present in an amount from 0.5 to 5.0 parts by mass, based on 100 parts by mass of the diene rubber; sulfur; and a vulcanization accelerator, the carbon black having DBP oil absorption of from 50×10 −5 to 80×10 −5 m 3 /kg, a nitrogen absorption specific area (N 2 SA) of 90 to 115 m 2 /g, and iodine adsorption of from 100 to 150 g/kg, wherein the rubber composition formed by mixing the diene rubber, the carbon black, the cobalt neodecanoate borate, the phenolic resin, the curing agent, the sulfur, and the vulcanization accelerator has a water content of 0.25 mass % or more, and wherein when the rubber composition is vulcanized it has characteristics of a dynamic storage modulus (E′) at a dynamic strain of 2% and at 20° C. of 8 MPa or more, a tangent loss (tan δ) at 60° C. of 0.20 or less, and the number of times of repetition until fracture is caused in a constant strain fatigue test at a strain of 60% and at 400 rpm of 45,000 or more

2. The rubber composition according to claim 1 , wherein a sulfenamide-based vulcanization accelerator is present in an amount of from 0.1 to 1.0 part by mass based on 100 parts by mass of the diene rubber.

3. A pneumatic tire comprising a belt layer formed from the rubber composition according to claim 1 .

4. A pneumatic tire comprising a belt layer formed from the rubber composition according to claim 2 .

Assignees

• Yokohama Rubber Co Ltd

Inventors

• Sugimoto Hiroki
• Nomaguchi Tsuyoshi

Classifications

• C08L7/00 Primary

  Compositions of natural rubber · CPC title

• B60C2001/0066

  Compositions of the belt layers · CPC title

• B60C1/00

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

• C08L61/04

  Condensation polymers of aldehydes or ketones with phenols only · CPC title

• C08K5/098

  Metal salts of carboxylic acids · CPC title