Heavy Load Tyre Tread with Modified Styrene-Butadiene Copolymer
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Solution Overview
Problem
Tires for heavy-load vehicles face challenges in achieving a balance between high wet grip, low rolling resistance, and good wear resistance, as improving one performance often compromises others, such as using rubber compositions that enhance grip but increase hysteresis and rolling resistance, or increasing reinforcing filler for wear resistance which can worsen rolling resistance.
Innovation Solution
A tire tread composition featuring a copolymer based on styrene and butadiene with a specific glass transition temperature, reinforced with silica, and a plasticizing system, along with a modifying agent that enhances the copolymer, providing a balance between wet grip, rolling resistance, and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rubber composition with good hysteretic potential is used to achieve high wet grip, then wet grip is improved, but rolling resistance increases due to high hysteresis
Solution Approach 1:
The patent applies parameter changes by precisely controlling the glass transition temperature (Tg) of the styrene-butadiene copolymer within a specific range (-65°C to -30°C) and adjusting the plasticizer content (2-15 phr) to optimize the balance between wet grip and rolling resistance. This parameter optimization allows the rubber composition to achieve both high hysteretic potential for wet grip and controlled hysteresis for acceptable rolling resistance
Solution Approach 2:
The patent uses composite materials by combining styrene-butadiene copolymer with specific plasticizers and modifiers to create a rubber composition that achieves both high wet grip and acceptable rolling resistance. The composite formulation includes copolymer (60-80 parts), plasticizer (2-15 parts), and modifier (0.1-5 parts), creating a material with optimized viscoelastic properties for simultaneous wet grip and rolling resistance performance
2Strength
If the rate of reinforcing filler is increased to improve wear resistance, then wear resistance is improved, but rolling resistance worsens due to increased hysteresis
Solution Approach 1:
The patent applies parameter changes by optimizing the reinforcing filler content within specific ranges (silica: 20-60 parts, carbon black: 5-20 parts) and adjusting the plasticizer to filler ratio. This controlled formulation ensures adequate reinforcement for wear resistance while preventing excessive hysteresis that would increase rolling resistance
Solution Approach 2:
The patent uses plasticizers as intermediary substances that mediate between the reinforcing filler and the copolymer matrix. The plasticizer (2-15 phr) acts as a lubricant and stress distributor, reducing the hysteresis generated by high filler content while maintaining the reinforcing effect, thereby decoupling wear resistance improvement from rolling resistance deterioration
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 both rolling resistance and wet grip performance while maintaining wear resistance, offering a compromise that surpasses existing tire technologies in these key performance areas.
Implementation Method 1
being capable to bond to said copolymer by a [3+2] type cycloaddition on a carbon-carbon double bond of the chain of said copolymer
Data Source
AI summary
A tyre for a vehicle carrying heavy loads, and comprising a tread having at least a rubber composition containing at least one elastomeric matrix comprising, as a major component, a styrene and butadiene copolymer with a glass transition temperature Tg strictly higher than -65°C and not exceeding -30°C; a reinforcing filler comprising silica as a major component; a chemical cross-linking system; a coupling agent for coupling the elastomeric matrix and the reinforcing filler; a plasticiser system comprising 2 to 15 phr of at least one plasticiser resin having a glass transition temperature Tg of at least 20°C, the total proportion of the plasticiser system in the composition ranging from 2 to 17 phr; and a modifier agent for modifying the styrene and butadiene copolymer, optionally already grafted onto said copolymer, which modifier agent is a 1,3-dipolar compound of general formula (I): A-E-D (I). The symbol D is a functional group comprising at least one nitrogen atom and capable of binding to the copolymer via a [3 +2]-type cycloaddition on a carbon-carbon double bond of the chain of said copolymer; the symbol E is a divalent spacer group linking group D to group A; A is a functional group selected from C1-C20 alkyls, C7-C18 alkylaryls, C7-C18 arylalkyls, optionally substituted, 5 to 6 atom nitrogen heterocycles, optionally substituted, 5 to 6 atom sulfur heterocycles, ester groups, phosphate groups, dialkylamino groups and associative groups comprising at least one nitrogen atom.