Heavy Load Tyre Tread Silica Composite Wear Resistance
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Solution Overview
Problem
Tires for heavy-load vehicles face challenges in achieving a balance between wear resistance, rolling resistance, and aggression resistance, as improving one performance often compromises others, particularly due to high hysteretic losses from increased reinforcing materials.
Innovation Solution
A tire tread composition featuring a styrene-butadiene copolymer in emulsion with a high butadiene unit content, combined with silica as a reinforcing filler and a specific plasticizing system, which includes a chemical crosslinking system and an agent for coupling silica with the elastomeric matrix, to enhance mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the stiffness of the tread is increased by increasing the rate of reinforcing filler (carbon black) and/or using high levels of synthetic elastomers, then wear resistance is improved, but rolling resistance increases due to high hysteretic losses
Solution Approach 1:
The patent changes the chemical composition parameters of the rubber compound by specifying a styrene-butadiene copolymer with at least 50% butadiene units (preferably 55-80%), using silica as the main reinforcing filler instead of carbon black, and incorporating a specific plasticizing system (2-17 phr total, with 2-15 phr of resin having Tg ≥ 20°C). This parameter optimization achieves wear resistance while reducing hysteretic losses and rolling resistance.
Solution Approach 2:
The patent creates a composite rubber compound combining styrene-butadiene copolymer (≥50% butadiene units), silica filler, coupling agent, and plasticizing system. This composite formulation provides both wear resistance and reduced rolling resistance by leveraging the complementary properties of each component, particularly the low hysteresis of high-butadiene-content SBR combined with silica reinforcement.
2Reliability
If the tread thickness is increased to improve resistance to attack for heavy-load vehicles, then durability is improved, but rolling resistance increases
Solution Approach 1:
The patent optimizes the rubber compound parameters to achieve high resistance to attack with reduced rolling resistance. The specific formulation (styrene-butadiene copolymer with ≥50% butadiene units, silica filler, coupling agent, and plasticizing system) provides superior mechanical properties and tear resistance that allow for thinner, more efficient tread designs with lower hysteretic losses.
Solution Approach 2:
The patent enhances the local quality of the rubber compound by concentrating reinforcing agents (silica with coupling agent) and optimizing the elastomer composition in the tread formulation. This localized reinforcement provides high resistance to attack and ground contact stresses while maintaining overall tread flexibility and low rolling resistance.
3Strength
If high levels of synthetic elastomers are used to improve tread stiffness and wear resistance, then mechanical strength is improved, but rolling resistance increases due to high hysteretic losses
Solution Approach 1:
The patent specifies a styrene-butadiene copolymer with at least 50% butadiene units (preferably 55-80%), which inherently exhibits lower hysteresis compared to other synthetic elastomers. This parameter selection for the elastomer composition provides the necessary tread stiffness and wear resistance while minimizing hysteretic energy losses and rolling resistance.
Solution Approach 2:
The patent uses silica as a reinforcing filler that replicates and enhances the reinforcing effect traditionally achieved with carbon black, but with superior properties. The silica-coupling agent system creates a reinforcement network that provides tread stiffness and wear resistance with lower hysteresis, effectively copying the functional benefits of high elastomer content without the associated energy losses.
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 composition achieves improved wear resistance, reduced rolling resistance, and enhanced resistance to aggression without compromising other performance metrics, demonstrating a favorable performance compromise.
Implementation Method 1
an elastomer matrix comprising in the majority a styrene-butadiene copolymer in emulsion
Implementation Method 2
a chemical crosslinking system
Implementation Method 3
an agent for coupling silica with the elastomeric matrix
Data Source
AI summary
The invention relates to a pneumatic tyre for a vehicle carrying heavy loads, said tyre having a tread comprising a rubber composition on the basis of at least: - an elastomer matrix comprising a styrene-butadiene copolymer in emulsion as the major constituent, said copolymer containing more than or equal to 50% by weight butadiene units in relation to the total weight of the copolymer, preferably from 55 to 80% by weight in relation to the total weight of the copolymer; - a reinforcing filler comprising silica as the major constituent, - a chemical crosslinking system, - a crosslinking agent for crosslinking the silica with the elastomer matrix, and - a plasticizer system comprising 2 to 15 phr, preferably 2 to 10 phr, of at least one plasticizing resin with a glass transition temperature Tg greater than or equal to 20°C, the total concentration of the plasticizer system in the composition being from 2 to 17 phr, preferably from 2 to 12 phr.