Functionalized Rubber Blend for Tire Tread
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Solution Overview
Problem
Existing rubber mixtures for tires face trade-offs between winter properties, abrasion resistance, rolling resistance, and wet grip, with improvements in one area often leading to deterioration in others, particularly when using silica as a filler.
Innovation Solution
A rubber blend comprising a high molecular weight solution-polymerized diene polymer A and a low molecular weight solution-polymerized polymer B, both functionalized with specific groups, is used in a sulfur-crosslinkable rubber mixture to enhance processing characteristics and achieve a balanced profile of winter, abrasion, and rolling resistance properties without compromising wet grip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silica is used as filler to replace carbon black, then wet grip and dry braking properties are improved, but rolling resistance and abrasion characteristics deteriorate
Solution Approach 1:
The patent applies parameter changes by using a dual polymer system with specifically controlled molecular weights and glass transition temperatures. Polymer A has high molecular weight (Mw > 350,000 g/mol) and low Tg (≤ -100°C) to reduce rolling resistance, while polymer B has low molecular weight (Mw: 1,300-10,000 g/mol) and higher Tg (≥ -50°C) to improve wet grip and processing. This precise parameter control allows simultaneous optimization of contradictory properties.
Solution Approach 2:
The patent employs composite materials by combining two distinct polymers (polymer A and polymer B) with complementary properties in a single rubber composition. This composite approach allows the benefits of both polymers to work together: polymer A provides low rolling resistance through its low Tg, while polymer B enhances wet grip through its higher Tg and functional groups that improve silica interaction.
2Reliability
If liquid polybutadiene is added to improve winter properties, then adhesion on ice and snow is enhanced, but processing characteristics and mixing behavior deteriorate
Solution Approach 1:
The patent resolves the processing issue by changing the molecular weight parameter of the low-Tg polymer to very high values (Mw > 350,000 g/mol). This high molecular weight provides viscosity and elasticity that improve processing characteristics, counteracting the negative effects of adding low-Tg polymer content.
Solution Approach 2:
The patent applies local quality by assigning different functional roles to different polymer components. Polymer A (high Mw, low Tg) specifically addresses rolling resistance and processing, while polymer B (low Mw, higher Tg) specifically addresses wet grip and winter properties. Each polymer is optimized for its specific function rather than trying to achieve all properties in a single component.
3Loss of energy
If polymer with low glass transition temperature is used to reduce rolling resistance, then fuel consumption is reduced, but wet grip and adhesion properties deteriorate
Solution Approach 1:
The patent applies segmentation by dividing the rubber composition into two distinct polymer segments with different Tg values. Polymer A (Tg ≤ -100°C) handles the rolling resistance function, while polymer B (Tg ≥ -50°C) handles the wet grip function. This segmentation allows each polymer to specialize in one property rather than compromising both.
Solution Approach 2:
The patent uses composite materials by combining polymers with complementary Tg values. The low-Tg polymer provides low rolling resistance through reduced hysteresis losses, while the high-Tg polymer provides wet grip through better adhesion at operating temperatures. The composite system achieves properties that neither polymer could achieve alone.
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 blend improves handling characteristics, abrasion resistance, and winter properties while maintaining wet grip performance, achieving a balanced relationship between these properties in tire applications.
Implementation Method 1
at least one of the solution-polymerized diene polymer A of high molecular weight and the solution-polymerized polymer B of low molecular weight has been functionalized at the chain end and/or along the polymer chain and/or at a coupling site with at least one group selected from epoxy groups, hydroxyl groups, carboxyl groups, silane sulfide groups, amino groups, siloxane groups, organosilicon groups, phthalocyanine groups
Implementation Method 2
a sulfur-crosslinkable rubber mixture comprising the rubber blend
Data Source
AI summary
The invention relates to a rubber blend, to a sulfur-crosslinkable rubber mixture comprising the rubber blend and to a vehicle tire comprising such a rubber mixture.The rubber blend comprisesat least one solution-polymerized diene polymer A of high molecular weight andat least one solution-polymerized polymer B of low molecular weight,wherein at least one of polymers A and B has been functionalized at the chain end and/or along the polymer chain and/or at a coupling site with at least one group selected from epoxy groups, hydroxyl groups, carboxyl groups, silane sulfide groups, amino groups, siloxane groups, organosilicon groups, phthalocyanine groups and amino group-containing alkoxysilyl groups.