Tire Rubber Composition Balancing Cutting Resistance and Fuel Efficiency

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Solution Overview

Problem

Existing rubber compositions used in tires, particularly those based on diene-based rubbers, lack sufficient breaking resistance, especially cutting resistance, under high strain input, which affects durability and fuel efficiency.

Innovation Solution

A rubber composition incorporating natural rubber and/or synthetic isoprene rubber combined with syndiotactic 1,2-polybutadiene, optimized for crystal content and molecular weight, to form a double network structure that enhances wear resistance and cutting resistance while maintaining good fuel efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If diene-based rubbers (BR, SBR) are used to improve fuel efficiency and processing, then fuel efficiency is improved, but cutting resistance and breaking resistance under high strain input deteriorate

Engineering Contradiction:
Improvefuel efficiencyVSAvoidcutting resistance
Core Design Contradiction:
Use of energy by moving objectVSStrength

Solution Approach 1:

The patent combines natural rubber (NR) or synthetic isoprene rubber (IR) with syndiotactic 1,2-polybutadiene (sPB) to create a composite rubber composition. This composite structure leverages the high cutting resistance of NR/IR while incorporating sPB's fuel efficiency benefits, achieving both durability and energy efficiency simultaneously.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes specific parameters of syndiotactic 1,2-polybutadiene, including crystal content (5-20 J/g) and number-average molecular weight (6.5×10^4 or more), to achieve the desired balance between fuel efficiency and cutting resistance. By precisely controlling these parameters, the composition achieves optimal performance.

Inventive Principle:
Principle #35Parameter changes

2Strength

If natural rubber is used to improve cutting resistance, then cutting resistance is improved, but fuel efficiency deteriorates

Engineering Contradiction:
Improvecutting resistanceVSAvoidfuel efficiency
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The patent creates a composite system where natural rubber or synthetic isoprene rubber provides the cutting resistance, while syndiotactic 1,2-polybutadiene contributes to fuel efficiency. The synergistic interaction between these components resolves the contradiction between durability and energy consumption.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent assigns different functional roles to different components: NR/IR primarily provides cutting resistance and structural integrity, while sPB primarily contributes to fuel efficiency and elasticity. This functional differentiation allows each component to excel at its specific function without compromising overall performance.

Inventive Principle:
Principle #3Local quality

3Strength

If crystal content of syndiotactic 1,2-polybutadiene is increased to improve wear resistance, then wear resistance is improved, but processing difficulty increases

Engineering Contradiction:
Improvewear resistanceVSAvoidprocessing difficulty
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent optimizes the crystal content of syndiotactic 1,2-polybutadiene to a specific range (5-20 J/g) that provides sufficient wear resistance while maintaining processability. This parameter optimization ensures that the material achieves the desired mechanical properties without becoming too difficult to process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates local crystalline structures within the rubber composition that provide wear resistance only where needed, while the rest of the material remains processable. The crystalline regions are distributed throughout the matrix, providing localized reinforcement without making the entire material rigid and difficult to process.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The proposed rubber composition significantly improves wear resistance and cutting resistance while maintaining excellent fuel efficiency when applied to tires, thereby enhancing the overall performance and durability of tire components.

Implementation Method 1

a second monomer component is introduced into a network structure formed by polymerizing and cross-linking a first monomer component

Methodology Applied
Scientific EffectCross-linking: Chemical Bonding

Implementation Method 2

the syndiotactic 1,2-polybutadiene has a crystal content of 7 J/g to 40 J/g

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Data Source

PatentUS12202977B2Rubber composition and tire
Publication Date: 2025.01.21 BRIDGESTONE CORP

AI summary

Provided is rubber composition that can improve wear resistance and cutting resistance while having good fuel efficiency when applied to a tire. The rubber composition contains a rubber component containing natural rubber and/or synthetic isoprene rubber, and syndiotactic 1,2-polybutadiene, where the syndiotactic 1,2-polybutadiene has a crystal content of 7 J/g to 40 J/g and a number-average molecular weight of 6.5×104 or more.