Functionalized Polymer Blends for Tire Wear
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Solution Overview
Problem
The tire industry faces a compromise between improving tire wear and maintaining wet braking performance, as enhancements in one area often lead to a significant decline in another desired characteristic.
Innovation Solution
A rubber composition for tire treads is developed, comprising a blend of middle-chain and end-chain functionalized highly unsaturated elastomers, along with a silica filler and a plasticizing system, which enhances wear performance without significantly impacting wet braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If tire composition is modified to improve wear properties, then wear resistance is improved, but wet braking performance deteriorates
Solution Approach 1:
The patent uses a composite rubber composition blending three different elastomers (polybutadiene, styrene-butadiene rubber, and styrene-isoprene-styrene block copolymer) with distinct functional properties. Each elastomer contributes different characteristics: polybutadiene provides wear resistance, SBR contributes to wet braking, and SIS provides toughness. This composite approach allows simultaneous optimization of wear resistance and wet braking performance by combining materials with complementary properties rather than relying on a single elastomer.
Solution Approach 2:
The patent applies different elastomers to different functional requirements within the tire tread. The composition is designed so that each elastomer type serves a specific local function: polybutadiene for wear resistance, SBR for wet braking traction, and SIS for overall toughness and processability. This localized functional assignment within the composite material allows the tire to exhibit optimized performance in both wear and wet braking without compromise.
2Strength
If silica filler content is increased to improve wear, then wear resistance improves, but processing difficulty increases
Solution Approach 1:
The patent optimizes the silica filler content to a specific range (50-150 phr) and controls the glass transition temperature of the plasticizing resin to be at least 25°C. These parameter adjustments ensure that the silica-reinforced rubber composition maintains adequate processability during manufacturing while achieving the desired wear resistance in the final product. The controlled Tg of the plasticizing resin prevents excessive stiffness during processing that would make manufacturing difficult.
Data Source
AI summary
A tire tread formed at least in part from a rubber composition that is based upon a cross-linkable rubber composition that may include between 50 phr and 90 phr of a first highly unsaturated elastomer being middle chain functionalized with an aminoalkoxysilane group and having a Tg of between −108° C. and −45° C. and between 10 phr and 50 phr of a second highly unsaturated elastomer being end-chain functionalized with a silanol group and having a Tg of between −108° C. and −10° C. The rubber composition may further include between 50 phr and 150 phr of a silica filler and a plasticizing system comprising between 5 phr and 120 phr of a plasticizing resin having a Tg of at least 25° C. and between 0 phr and 60 phr of a plasticizing liquid.