Styrene-Butadiene Outsole Wet Grip and Durability
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Solution Overview
Problem
Existing shoe outsoles do not adequately provide grip performance on wet surfaces and lack durability, especially when walking on uneven terrain.
Innovation Solution
The outsole is designed with a viscoelastic body containing a rubber component, specifically a styrene-butadiene random copolymer rubber, silica, and a silane coupling agent, which enhances wet grip performance and durability by optimizing viscoelasticity characteristics and hysteresis frictional forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional rubber composition (styrene-butadiene rubber with 23% styrene content) is used for the outsole, then the manufacturing process is simple and cost-effective, but the wet grip performance is insufficient
Solution Approach 1:
The patent changes the critical parameter of styrene content in styrene-butadiene rubber from the conventional 23% to 35% or more. This parameter change fundamentally alters the rubber's viscoelastic properties, increasing the loss factor (tan δ) at 0°C which directly improves wet grip performance while maintaining the vulcanization molding manufacturing process
Solution Approach 2:
The patent creates a composite rubber composition by combining styrene-butadiene rubber (35%+ styrene) with specific additives including silane-modified rubber (5-20 parts by mass per 100 parts SBR), silica (20-60 parts by mass), and various functional agents. This composite structure achieves both improved wet grip and durability while remaining manufacturable through conventional vulcanization processes
2Reliability
If the rubber composition is optimized for wet grip performance (higher styrene content), then grip performance improves, but the material becomes stiffer and less adaptable to uneven surfaces
Solution Approach 1:
The patent carefully balances the styrene content parameter (35-60%) to achieve optimal viscoelasticity. Additionally, it controls the glass transition temperature (Tg) of the base rubber to be -50°C or higher, and adjusts the loss factor (tan δ) at 0°C to be 0.40 or more but not exceeding 0.80, creating a rubber composition that is sufficiently soft to conform to uneven surfaces while maintaining excellent wet grip performance
Solution Approach 2:
The patent uses a composite formulation incorporating silane-modified rubber (providing flexibility and adhesion), silica (reinforcement), and specific plasticizers to balance the stiffness from high styrene content. This composite approach ensures the outsole remains adaptable to uneven terrain while achieving superior wet grip characteristics
3Adaptability or versatility
If the outsole material is made softer to improve adaptability to uneven surfaces, then adaptability improves, but the durability and wear resistance decrease
Solution Approach 1:
The patent employs a composite reinforcement strategy by incorporating silica (20-60 parts by mass per 100 parts SBR) and silane-modified rubber (5-20 parts by mass). The silica provides exceptional wear resistance and structural integrity, while the silane-modified rubber enhances adhesion and flexibility. This composite structure enables the outsole to be both soft enough for adaptability and durable enough for long-term use
Solution Approach 2:
The patent applies different functional components to different aspects of the rubber composition: the base SBR provides overall flexibility and adaptability, silica provides localized reinforcement and wear resistance, and the silane-modified rubber provides localized adhesion enhancement. This local quality differentiation allows the material to simultaneously achieve softness for adaptability and hardness for durability
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 outsole achieves excellent wet grip performance and durability, preventing slipping on wet surfaces and ensuring long-term use without significant wear.
Implementation Method 1
silane coupling agent having in a molecular structure a structure represented by at least the following Formula (2) between the following Formula (1) and Formula (2)
Implementation Method 2
The viscoelastic body has a loss factor [tan δ] measured by a dynamic viscoelasticity measurement under conditions of a temperature of 23° C., a frequency of 10 Hz, a static strain of 10%, and a dynamic strain of 7% being 0.17 or more
Implementation Method 3
optimizing viscoelasticity characteristics and hysteresis frictional forces
Implementation Method 4
the outsole is designed with a viscoelastic body containing a rubber component, specifically a styrene-butadiene random copolymer rubber
Data Source
AI summary
An outsole is formed of a viscoelastic body containing a rubber component. This viscoelastic body has a loss factor measured by a dynamic viscoelasticity measurement under conditions of a temperature of 23° C., a frequency of 10 Hz, a static strain of 10%, and a dynamic strain of 7% being 0.17 or more, a storage elastic modulus measured by the dynamic viscoelasticity measurement being 5.7 MPa or less, and a ratio of a tensile stress at 300% elongation to a tensile stress at 100% elongation being 4.4 or more. Such outsole is excellent in wet grip performance and durability.