Liquid Crystal Elastomer Rubber Composition for Tire Wet Grip and Fuel Efficiency
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Solution Overview
Problem
Existing rubber compositions struggle to balance wet grip performance (WET performance) and fuel efficiency in pneumatic tires, as technologies fail to effectively optimize the loss tangent (tan δ) at different temperatures, leading to suboptimal results in both areas.
Innovation Solution
Incorporating a diene rubber with a liquid crystal elastomer or polymer filler, specifically a liquid crystal polyurethane elastomer with a (liquid crystal phase)-to-(isotropic phase) transition temperature of 20° C. or less, to enhance tan δ at 0° C. while reducing it at 60° C., thereby improving the balance between these performance metrics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the formulation is designed to improve WET performance by increasing tan δ at 0°C, then wet grip performance is improved, but fuel efficiency deteriorates due to increased tan δ at 60°C
Solution Approach 1:
The patent applies parameter changes by carefully selecting and controlling the molecular weight, composition, and structure of liquid copolymer components to achieve a rubber composition where tan δ at 0°C is increased (improving wet grip) while tan δ at 60°C is kept low (maintaining fuel efficiency). This is accomplished by adjusting the types and ratios of monomers in the liquid copolymer to create specific viscoelastic properties.
Solution Approach 2:
The patent uses composite materials by combining multiple rubber components including liquid copolymers with different characteristics. Specifically, it combines liquid copolymers containing aromatic vinyl compounds and conjugated dienes with other rubber materials to create a synergistic effect where the composite composition achieves both high tan δ at 0°C and low tan δ at 60°C, resolving the contradiction between wet grip and fuel efficiency.
2Reliability
If tan δ at 0°C is increased to improve WET performance, then grip on wet road surface is improved, but the balance between tan δ at 0°C and tan δ at 60°C becomes difficult to achieve
Solution Approach 1:
The patent applies parameter changes by precisely controlling the molecular weight distribution, monomer composition ratios, and structural parameters of the liquid copolymer. By adjusting these parameters, the patent achieves a rubber composition with tan δ at 0°C of 0.4 or more (improving grip) while maintaining tan δ at 60°C at appropriate levels, thus achieving the desired balance across temperatures.
Solution Approach 2:
The patent applies local quality by creating different functional regions within the rubber composition through the use of liquid copolymers with specific local molecular structures. The liquid copolymer segments with aromatic vinyl compounds provide one set of properties (affecting tan δ at 0°C) while other segments provide different properties (affecting tan δ at 60°C), allowing each component to contribute locally to the overall temperature-dependent performance.
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 composition achieves a well-balanced tan δ at 0° C. and 60° C., resulting in improved WET performance and fuel efficiency of pneumatic tires, with the liquid crystal elastomer or polymer filler enhancing dispersibility and rubber properties.
Implementation Method 1
a liquid crystal elastomer having a (liquid crystal phase)-to-(isotropic phase) transition temperature (Ti) of 20° C. or less
Implementation Method 2
Liquid crystal elastomers exhibit specific dynamic viscoelasticity as compared with diene rubbers, and have high heat loss over a wide temperature range
Implementation Method 3
Liquid crystal elastomers exhibit specific dynamic viscoelasticity as compared with diene rubbers
Data Source
AI summary
A rubber composition comprising a diene rubber and a liquid crystal elastomer. It is preferred that the liquid crystal elastomer has a (liquid crystal phase)-to-(isotropic phase) transition temperature (Ti) of 20° C. or less. It is preferred that the liquid crystal elastomer has a functional group that reacts with the diene rubber. It is preferred that the functional group is a functional group containing at least a sulfur atom. It is preferred that the liquid crystal elastomer is a liquid crystal polyurethane elastomer. Moreover, it is preferred that the liquid crystal polyurethane elastomer is a reaction product of a mesogenic group-containing compound having at least an active hydrogen group, an isocyanate compound, a polysulfide-containing compound, and a photopolymerizable group-containing compound.