Multi-Phase Rubber Composition for Tire Ice Traction and Wear
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Solution Overview
Problem
Conventional studless tires face a trade-off between improving on-ice performance and wear resistance, as soft tread rubber enhances ice traction but compromises dry road durability, and existing rubber compositions with additives like potassium titanate fibers do not adequately improve ice friction coefficients.
Innovation Solution
A rubber composition comprising at least three types of diene polymers with specific glass transition temperatures and modifications, along with silica and carbon black, forming immiscible polymer phases to enhance both on-ice performance and wear resistance, including the use of a foaming agent and hydrophilic short fibers for improved drainage and traction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tread rubber is made relatively soft to improve on-ice performance, then on-ice performance is improved, but wear resistance deteriorates
Solution Approach 1:
The tread rubber is divided into multiple polymer phases with different glass transition temperatures, where each phase segment contributes differently to the overall performance. The low-Tg phase provides softness for ice traction while the high-Tg phase maintains structural integrity for wear resistance, resolving the contradiction through functional segmentation of the rubber matrix.
Solution Approach 2:
Different regions of the rubber composition have different local properties through the immiscible polymer phases. The low-Tg polymer regions provide local softness for ice contact, while high-Tg polymer regions provide local strength for wear resistance, allowing both softness and durability to coexist in different locations within the same material.
2Reliability
If organic fibers or glass fibers are blended with rubber composition to improve on-ice performance, then on-ice performance is improved, but fracture resistance deteriorates
Solution Approach 1:
Silica acts as an intermediary substance that mediates between the polymer phases and provides reinforcement without acting as a stress concentration point like organic fibers. The silica particles interact with the rubber matrix to enhance fracture resistance while the polymer phase composition maintains on-ice performance, resolving the contradiction by replacing direct fiber-rubber interaction with silica-mediated reinforcement.
Solution Approach 2:
The invention uses a composite system of immiscible polymer phases combined with silica reinforcement, creating a multi-phase composite material that achieves both ice performance and fracture resistance. The composite structure allows the low-Tg phase to provide ice traction while the high-Tg phase and silica provide structural strength, avoiding the brittleness introduced by organic fibers.
3Reliability
If potassium titanate fiber is added to rubber composition to improve on-ice performance, then on-ice performance is improved, but wear resistance deteriorates
Solution Approach 1:
The invention changes the fundamental parameters of the rubber composition by using multiple polymer phases with different glass transition temperatures instead of adding fiber reinforcements. This parameter change in the base polymer system allows achieving ice performance through the low-Tg phase while maintaining wear resistance through the high-Tg phase, avoiding the wear deterioration caused by potassium titanate fibers.
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 significantly enhances on-ice performance while maintaining or improving wear resistance, providing a studless tire with improved traction and durability on both icy and dry surfaces.
Implementation Method 1
at least three types of diene polymers forming a plurality of polymer phases which are immiscible with each other
Implementation Method 2
the silica has content of ≥25 parts by mass with respect to the total mass or 100 parts by mass of the diene polymers
Data Source
AI summary
A rubber composition has: at least three types of diene polymers forming a plurality of polymer phases immiscible with each other; and silica, wherein: a diene polymer (B), of which glass transition temperature (Tg) is neither the highest nor the lowest among the diene polymers each having content of ≥10% by mass with respect to the total mass of the diene polymers, has been modified by a compound containing silicon atom; the diene polymer (B) satisfies formula (i) shown below:St+Vi/2≤33 (i)(In the formula, “St” represents content of bonded styrene (mass %) of the diene polymer (B) and “Vi” represents vinyl bond content (mass %) of a conjugated diene compound part of the diene polymer (B)); and the silica has content of ≥25 parts by mass with respect to the total mass or 100 parts by mass of the diene polymers.