Terminal-Modified Diene Rubber Tire Tread Hardness
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Solution Overview
Problem
Pneumatic tire base tread rubber compositions using terminal-modified diene rubber face challenges in maintaining hardness while achieving low fuel consumption and driving stability, often compromising on flexural fatigue characteristics.
Innovation Solution
A rubber composition incorporating terminal-modified diene rubber with a number average molecular weight of 150,000 to 400,000, combined with a specific vulcanizing agent represented by the formula (R-benzyl group, n=3-12), and a filler like carbon black, to enhance hardness without degrading low fuel consumption or flexural fatigue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the number of terminals is increased and a larger amount of modifier is added to improve low fuel consumption property, then the low fuel consumption property is improved, but the hardness of the rubber composition is reduced
Solution Approach 1:
The patent specifies a particular number average molecular weight range (150,000 to 400,000) for the terminal-modified diene rubber to optimize the balance between low fuel consumption property and hardness. This parameter control prevents excessive hardness reduction while maintaining the low rolling resistance benefits
Solution Approach 2:
The patent creates a composite rubber composition by combining terminal-modified diene rubber with specific vulcanizing agents (0.5 to 5 parts by weight per 100 parts rubber component) and fillers. This composite approach enhances hardness through filler-rubber interactions and controlled crosslinking while preserving the low fuel consumption properties
2Strength
If the amount of filler is increased or the amount of oil is decreased to enhance hardness, then the hardness is improved, but the low fuel consumption property is degraded
Solution Approach 1:
The patent optimizes the filler content within specific ranges and controls the oil amount to maintain the low fuel consumption property. By precisely controlling these parameters alongside the rubber molecular weight, the composition achieves both adequate hardness and low rolling resistance
3Strength
If the crosslinking density is increased by increasing the amount of sulfur to enhance hardness, then the hardness is improved and low fuel consumption property is maintained, but the flexural fatigue characteristic is degraded
Solution Approach 1:
The patent carefully controls the sulfur amount and vulcanizing agent dosage (0.5 to 5 parts by weight per 100 parts rubber component) to achieve optimal crosslinking density. This controlled approach ensures adequate hardness and low fuel consumption property while preventing excessive crosslinking that would harm flexural fatigue characteristics
Solution Approach 2:
The patent uses a composite vulcanization system combining sulfur with specific vulcanizing agents and fillers. This composite approach creates a balanced crosslinking structure that maintains flexibility and fatigue resistance while achieving the desired hardness and low rolling resistance
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 solution effectively improves hardness and maintains compatibility between low fuel consumption and driving stability without impairing flexural fatigue characteristics, ensuring better tire performance.
Implementation Method 1
the dispersibility of the filler is improved by the effect of the modifier for the terminal
Implementation Method 2
the crosslinking density is increased by an increase in amount of sulfur as a vulcanizing agent for the enhancement in hardness
Data Source
AI summary
The rubber composition for a tire base tread includes a rubber component containing not less than 15% by weight of a terminal-modified diene rubber having a number average molecular weight prior to modification of 150000 to 400000, a filler, and a compound (vulcanizing agent) represented by the following general formula (1) in an amount of 0.5 to 5 parts by weight based on 100 parts by weight of the rubber component:(wherein R represents a benzyl group, and n represents an integer of 3 to 12.)