Tread Rubber Composition for Icy-Road Braking Durability
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Solution Overview
Problem
Tires experience deterioration in braking performance on icy roads due to tread wear, leading to potential accidents, especially after repeated use.
Innovation Solution
A tire with a tread portion featuring a cap rubber layer composed of a rubber composition containing 40-80 parts by mass of styrene-butadiene rubber (SBR) with 25% or less styrene content, combined with silica and carbon black, and having a loss tangent of less than 0.25, along with a carbon black content exceeding 15 parts by mass and a silica-to-carbon black ratio of 1 or more, and a tread thickness of 15 mm or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the tread portion is made thicker to improve durability, then the tire can withstand more wear, but heat accumulation increases leading to faster performance deterioration on icy roads
Solution Approach 1:
The patent optimizes the tread thickness parameter to 15mm or less, and adjusts the rubber composition parameters (SBR content: 40-80 parts, silica content: 20-80 parts, carbon black content: 15-60 parts) to achieve the right balance between durability and heat dissipation. This parameter optimization allows the tread to be thin enough to dissipate heat effectively while maintaining sufficient durability for icy road conditions.
Solution Approach 2:
The patent uses a composite rubber composition containing multiple fillers (silica and carbon black) combined with SBR. This composite material structure improves both the durability and thermal properties of the tread, allowing it to withstand wear while managing heat accumulation effectively on icy roads.
2Force
If silica content is increased to improve friction on icy roads, then braking performance improves, but heat accumulation increases causing performance deterioration
Solution Approach 1:
The patent optimizes the silica content to 20-80 parts and carbon black content to 15-60 parts, with their ratio controlled between 0.3-2.0. This balanced parameter setting ensures sufficient friction on icy roads while preventing excessive heat accumulation that would lead to performance deterioration.
Solution Approach 2:
The patent uses a composite filler system combining silica and carbon black in specific proportions. This composite approach balances the high friction provided by silica with the heat dissipation properties of carbon black, achieving both improved icy road friction and controlled heat accumulation.
3Strength
If SBR with high styrene content is used to improve wear resistance, then tread durability increases, but loss tangent increases leading to more heat accumulation
Solution Approach 1:
The patent specifies SBR content of 40-80 parts and controls the styrene content to be 25% by mass or less. This parameter optimization provides sufficient wear resistance while keeping the loss tangent low to minimize heat generation during braking operations on icy roads.
Solution Approach 2:
The patent combines SBR with silica and carbon black in a composite rubber composition. This composite material structure enhances wear resistance through the reinforcing fillers while the base SBR polymer maintains low heat generation characteristics, resolving the contradiction between durability and energy loss.
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
This configuration effectively suppresses braking performance deterioration on icy roads by preventing heat accumulation, enhancing friction, and maintaining effective braking even after repeated use.
Implementation Method 1
the loss tangent 30°C tan δ of less than 0.25 measured under the conditions of temperature of 30°C, frequency of 10 Hz, initial strain of 5%, dynamic strain rate of 1%, and deformation mode: tensile
Implementation Method 2
containing silica and carbon black together with the rubber component, and having the loss tangent 30°C tan δ of less than 0.25
Data Source
AI summary
A tire having a tread portion, which can suppress deterioration in braking performance of tires on an icy road surface after repeated running; and the cap rubber layer forming the tread portion is formed from a rubber composition containing 40 parts by mass or more and 80 parts by mass or less of styrene-butadiene rubber (SBR) having a styrene content of 25% by mass or less in 100 parts by mass of the rubber component, containing silica and carbon black together with the rubber component, and having the loss tangent 30°C tan δ of less than 0.25 measured under the conditions of temperature of 30°C, frequency of 10 Hz, initial strain of 5%, dynamic strain rate of 1%, and deformation mode: tensile; in the rubber composition, the carbon black content is more than 15 parts by mass with respect to 100 parts by mass of the rubber component, and the ratio of the silica content to the carbon black content is 1 or more; and the thickness of the tread portion is 15 mm or less.