Vegetable-Oil Extended SSBR Outsole for Wet Traction and Flexibility
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Solution Overview
Problem
Conventional footwear soles lack high traction and durability, particularly in wet conditions, and existing high Tg SSBR compositions are too stiff, limiting their performance in varying temperatures.
Innovation Solution
A rubber composition for shoe soles using vegetable triglyceride oil-extended high Tg styrene/butadiene elastomer, combined with reinforcing fillers like carbon black and precipitated silica, and optionally including corncob granules, to enhance traction and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high Tg SSBR is used to promote wet traction, then traction is improved, but the rubber composition becomes too stiff
Solution Approach 1:
The patent changes the chemical composition parameters of the rubber compound by incorporating high Tg SSBR (20-45 parts per 100 parts elastomer) with specific glass transition temperatures (-20°C to +10°C) and bound styrene content (25-50%), combined with precipitated silica (50-100 parts per 100 parts rubber) and carbon black (20-70 parts per 100 parts rubber). This parameter optimization achieves both improved wet traction through the high Tg SSBR and maintained flexibility through the balanced filler composition and silica coupling agent system.
Solution Approach 2:
The patent creates a composite rubber composition combining multiple elastomers (high Tg SSBR, cis-1,4-polybutadiene, and optionally other diene elastomers) with reinforcing fillers (precipitated silica and carbon black). The synergistic interaction between these components, particularly the silica coupling agent bridging the polymer and filler, achieves both the desired traction performance and flexibility that neither component could provide alone.
2Duration of action of stationary object
If reinforcing filler is increased to improve durability, then durability is improved, but the rubber composition becomes stiffer
Solution Approach 1:
The patent introduces a silica coupling agent as an intermediary substance that chemically bridges the precipitated silica filler and the rubber polymer matrix. This coupling agent (typically silane-based) creates strong chemical bonds between the inorganic silica particles and the organic polymer, allowing the silica to provide reinforcement and durability while maintaining flexibility by preventing stress concentration at the filler-polymer interface.
Solution Approach 2:
The patent optimizes the ratio and type of reinforcing fillers, using predominantly precipitated silica (50-100 parts per 100 parts rubber) with controlled particle size distribution and surface treatment. The combination of silica and carbon black in specific proportions, along with the coupling agent concentration, creates a balanced composite that delivers durability through reinforcement while preserving the necessary flexibility for footwear application.
Data Source
AI summary
An outsole for a shoe is disclosed. The outsole is intended to be ground-contacting and comprises a rubber composition comprising, based on parts by weight per 100 parts by weight elastomer (phr): (A) conjugated diene-based elastomer comprising: (1) from 20 to 45 phr of styrene/butadiene elastomer (SSBR) pre-extended with vegetable triglyceride oil, wherein said SSBR has a glass transition temperature (Tg) in a range of from -20°C to +10°C, a bound styrene content in a range of from 25 to 50 percent and a vinyl 1,2-content in a range of from 10 to 80 percent based on butadiene content; (2) from 55 to 80 phr of at least one additional conjugated diene-based elastomer comprising at least one of polybutadiene, polyisoprene rubber, cis 1,4-polyisoprene rubber, acrylonitrile-butadiene rubber and combinations thereof; and (B) from 20 to 70 phr of a reinforcing filler comprising a combination of a rubber reinforcing carbon black and silica, preferably precipitated silica, where the reinforcing filler comprises from 50 to 100 weight percent of said silica, preferably precipitated silica.