Heavy-Duty Tyre Tread Composition for Crack Resistance
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Solution Overview
Problem
Heavy-duty vehicle tires face accelerated tread crack propagation due to mechanical stresses and aggressive road surfaces, leading to reduced tire life, particularly on stony ground and under heavy loads.
Innovation Solution
A tire tread composition combining a styrenic thermoplastic elastomer, polybutadiene or butadiene copolymer, silica, carbon black, a coupling agent, and a crosslinking system, optimized to enhance resistance to crack propagation without compromising wear and rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heavy-duty vehicle tires use traditional tread compositions, then wear resistance and rolling resistance are maintained at acceptable levels, but resistance to crack propagation is insufficient leading to reduced tire life
Solution Approach 1:
The patent applies composite materials by combining styrenic thermoplastic elastomer (10-45% by mass) with diene elastomer (more than 50% of the difference between elastomer matrix mass and thermoplastic elastomer mass) to create a tread composition that simultaneously achieves crack propagation resistance and extended service life. This composite approach allows the rigid styrenic segments to provide crack resistance while the flexible diene segments maintain elasticity and durability.
Solution Approach 2:
The patent changes the chemical composition parameters of the tread by incorporating specific amounts of styrenic thermoplastic elastomer (10-45% by mass) and diene elastomer with defined glass transition temperatures. This parameter modification transforms the tread's mechanical properties to resist crack propagation while maintaining acceptable wear and rolling resistance characteristics.
2Reliability
If the tread uses natural rubber to improve crack propagation resistance, then crack resistance improves, but wear resistance and rolling resistance deteriorate substantially
Solution Approach 1:
The patent replaces natural rubber with a composite system of styrenic thermoplastic elastomer and diene elastomer. The styrenic thermoplastic elastomer provides crack propagation resistance through its rigid styrenic segments, while the diene elastomer component maintains wear resistance and rolling resistance properties, avoiding the substantial deterioration caused by natural rubber.
Solution Approach 2:
The patent applies local quality by using rigid styrenic segments specifically for crack propagation resistance while using flexible diene segments for maintaining elasticity and wear properties. This localized functional distribution within the composite material allows each component to excel at its specific function without compromising overall performance.
3Force
If the tire operates on stony ground under heavy loads, then the tire must carry heavy loads and operate on aggressive surfaces, but crack propagation accelerates reducing tread life
Solution Approach 1:
The patent uses composite materials with styrenic thermoplastic elastomer and diene elastomer to create a tread that can withstand heavy loads and aggressive stony surfaces. The composite structure provides both the strength needed for load carrying and the crack propagation resistance needed to withstand mechanical stresses and road aggression.
Solution Approach 2:
The patent incorporates styrenic thermoplastic elastomer with rigid segments that provide beforehand cushioning against crack initiation and propagation. This preventive mechanism is built into the tread composition before the tire encounters heavy loads and aggressive surfaces, allowing the tread to resist crack propagation from the outset rather than failing after crack initiation.
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
Significantly improves the resistance to crack propagation in tire treads, extending the service life of heavy-duty vehicle tires by reducing the impact of incipient cracks and enhancing durability on aggressive surfaces.
Implementation Method 1
the elastomeric matrix comprises at least one styrenic thermoplastic elastomer which represents from 10 to 45% by mass of the elastomeric matrix, which styrenic thermoplastic elastomer comprises at least one rigid styrenic segment and at least one flexible diene segment
Implementation Method 2
a diene elastomer chosen from the group consisting of polybutadienes, butadiene copolymers and mixtures thereof, which represents more than 50% of the difference between the mass of the elastomer matrix and the mass of the styrenic thermoplastic elastomer
Implementation Method 3
a reinforcing filler comprising silica between 50% and 99% by mass of the reinforcing filler, carbon black, between 1% and 50%, for example between 2% and 50%, by mass of the reinforcing filler
Implementation Method 4
a coupling agent and a crosslinking system
Implementation Method 5
a coupling agent and a crosslinking system
Data Source
AI summary
The present invention relates to a tyre for vehicles intended to bear heavy loads, the tread of which comprises a composition based on at least one elastomer matrix comprising at least one thermoplastic styrene elastomer which represents at most 50% by weight of the elastomer matrix, which thermoplastic styrene elastomer comprises at least one rigid styrene segment and at least one flexible diene segment, which flexible diene segment comprises at least 20% by weight of conjugated diene units, it being possible for the conjugated diene units to be completely or partly hydrogenated; a diene elastomer selected from the group consisting of polybutadienes, butadiene copolymers and mixtures thereof, which represents more than 0% of the difference between the weight of the elastomer matrix and the weight of the thermoplastic styrene elastomer; a reinforcing filler comprising silica between 50% and 99% by weight of the reinforcing filler, carbon black, between 2% and 50% by weight of the reinforcing filler, the content of reinforcing filler varying within a range extending from 25 to 60 phr; a coupling agent and a crosslinking system.