Natural Rubber Tire Composition Viscosity and Grip Optimization

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Solution Overview

Problem

Conventional rubber compositions using natural rubber as the principal component face challenges with low viscosity in the unvulcanized state, leading to poor workability, and high tan δ after vulcanization, which affects performance on snow, ice, and wet road surfaces.

Innovation Solution

A rubber composition comprising 60% or more natural rubber, 8 to 40 parts by mass of a thermoplastic resin, and 0.1 to 3 parts by mass of poly-p-dinitrosobenzene, with silica or carbon black as reinforcing fillers, enhances viscosity and reduces tan δ, improving workability and gripping properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If natural rubber is used as the principal rubber component, then the tire maintains fixed flexibility and secures friction on snow, ice, and wet road surfaces, but the unvulcanized rubber composition has low viscosity which deteriorates workability

Engineering Contradiction:
Improvefriction performance on snow, ice, and wet road surfacesVSAvoidworkability of unvulcanized rubber composition
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention changes the compositional parameters by introducing specific ratios of synthetic rubber (polybutadiene rubber and styrene-butadiene copolymer rubber) alongside natural rubber, and by optimizing the plasticizer content to 5-50 parts by mass per 100 parts of total rubber component. This parameter optimization resolves the contradiction by achieving the right balance between viscosity and flexibility

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite rubber system combining natural rubber (60-95 parts) with synthetic rubbers (polybutadiene rubber and styrene-butadiene copolymer rubber in specific ratios). This composite approach allows the material to exhibit both the high friction performance of natural rubber on cold/wet surfaces and improved processability through the synergistic effects of the synthetic rubber components

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If a plasticizer is applied to increase the viscosity of unvulcanized rubber composition, then workability is improved, but the tan δ of vulcanized rubber increases which deteriorates low temperature performance

Engineering Contradiction:
Improveworkability of unvulcanized rubber compositionVSAvoidlow temperature performance and friction on snow, ice, and wet road surfaces
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention optimizes the plasticizer content within a specific range (5-50 parts by mass per 100 parts of total rubber component) and selects plasticizers with appropriate molecular structures. This controlled parameter adjustment ensures sufficient viscosity for workability while limiting excessive plasticizer effects that would increase tan δ and reduce low-temperature performance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies different rubber components with specific functions: natural rubber provides friction performance on cold/wet surfaces, polybutadiene rubber contributes to elasticity and low-temperature flexibility, and styrene-butadiene copolymer rubber enhances overall mechanical properties. Each component is positioned to fulfill its specific quality requirement

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3243873B1Rubber composition, member for tread, pneumatic tire, and method for producing rubber composition
Publication Date: 2019.04.24 BRIDGESTONE CORP

AI summary

An object of the present invention is to enhance, in a rubber composition for tires comprising natural rubber as a principal component of a rubber component, a viscosity of the rubber composition in an unvulcanized state by providing the rubber composition with flexibility to improve workability of the rubber composition and improve a low loss tangent of the rubber composition after vulcanization while maintaining the performances both on snow and ice road surfaces and wet road surfaces. Used in the present invention is a rubber composition comprising a rubber component containing 60 % by mass or more of natural rubber, wherein the rubber composition comprises 8 to 40 parts by mass of a thermoplastic resin based on 100 parts by mass of the rubber component and poly-p-dinitrosobenzene.