Functionalized Styrene-Butadiene Rubber for Tire Rolling Resistance
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Solution Overview
Problem
Existing rubber mixtures for vehicle tires face a trade-off between improving rolling resistance and maintaining other critical properties like wet grip, abrasion resistance, and handling, with previous attempts often leading to deterioration in one or more of these properties.
Innovation Solution
A sulfur-crosslinkable rubber mixture containing 20 to 100 phr of functionalized styrene-butadiene copolymer with amino-containing alkoxysilyl groups and further alkoxysilyl groups, combined with 7 to 15 phf of blocked or unblocked mercaptosilane, and 20 to 300 phr of silica or carbon black, which enhances rolling resistance without compromising other tire properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silica is used to replace carbon black in rubber mixtures to improve wet grip and dry braking, then wet grip and dry braking are improved, but rolling resistance deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the rubber mixture by introducing functionalized diene rubber with specific functional groups (hydroxyl, amino, carboxyl, or epoxide groups) that can chemically bond to silica. This chemical functionalization modifies the interaction between rubber and filler at the molecular level, optimizing the balance between wet grip and rolling resistance through parameter changes in the rubber-filler interface
Solution Approach 2:
The patent creates a composite material system combining functionalized diene rubber, silica, and carbon black in specific proportions. The composite structure leverages the advantages of both fillers while mitigating their individual disadvantages, achieving improved wet grip from silica while maintaining acceptable rolling resistance through the synergistic combination and chemical bonding at interfaces
2Loss of energy
If the glass transition temperature of the rubber compound is reduced to optimize rolling resistance, then rolling resistance is improved, but abrasion behavior deteriorates
Solution Approach 1:
The patent modifies the glass transition temperature parameter within an optimized range (-50°C to -100°C) rather than minimizing it completely. This controlled parameter change improves rolling resistance while maintaining the rubber compound's durability and abrasion resistance by preserving adequate polymer chain mobility and crosslinking density
Solution Approach 2:
The patent applies local quality enhancement through functional groups concentrated at the rubber-filler interface. The functionalized diene rubber creates localized regions of enhanced bonding at the interface between rubber matrix and filler particles, while the bulk rubber properties are optimized separately for rolling resistance, achieving both goals through spatial differentiation of properties
3Loss of energy
If the degree of filling is reduced to improve rolling resistance, then rolling resistance is improved, but other tire properties deteriorate
Solution Approach 1:
The patent changes the filler content parameter to an optimized range (20-40 phr silica and 20-40 phr carbon black) rather than using minimal filling. This moderate filling level, combined with functionalization, provides sufficient reinforcement for tire properties while limiting the pro-rolling-resistance effect of excessive filling
Solution Approach 2:
The patent employs a composite filling system combining silica and carbon black in specific ratios, creating a dual-filler composite that provides synergistic reinforcement. This composite approach maintains tire properties such as abrasion resistance and strength while the functionalized rubber matrix ensures adequate bonding at lower overall filler concentrations
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 rubber mixture significantly improves rolling resistance indicators while maintaining or improving other key properties such as wet grip and abrasion resistance, resulting in a more efficient tire performance.
Implementation Method 1
functionalized styrene-butadiene copolymer having at least one chain end with an amino group-containing alkoxysilyl group and at least one further alkoxysilyl group(s) and/or at least one further amino group-containing alkoxysilyl group(s)
Implementation Method 2
a sulfur-crosslinkable rubber mixture
Data Source
AI summary
The invention relates to a sulfur-crosslinkable rubber compound, in particular for treads of vehicle tires, and to a vehicle tire. The sulfur-crosslinkable rubber compound contains: - 20 to 100 phr of at least one functionalized styrene-butadiene copolymer A, wherein the functionalized styrene-butadiene copolymer is functionalized at at least one end of each polymer chain with an amino-group-containing alkoxysilyl group and at least one further alkoxysilyl group(s) and/or at least one further amino-group-containing alkoxysilyl group(s), and - 7 to 15 phr of at least one blocked and/or unblocked mercaptosilane, and - 20 to 300 phr of silica and/or carbon black.