Transparent Rubber Composition for Shoe Soles
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Solution Overview
Problem
Current transparent rubber compositions for shoe soles lack sufficient abrasion resistance while maintaining transparency and mechanical properties, particularly in sport shoes where lower abrasion resistance is required.
Innovation Solution
A curable transparent rubber composition comprising 35-60 wt.% of synthetic isoprene polymers and 35-60 wt.% of transparent polymers with similar refractive indices, along with a curing agent, co-agent, and 1-4 wt.% of polyalkenamers, which is processed to achieve haze less than 30% and total light transmission greater than 80%, enhancing abrasion resistance and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If transparent rubber compositions are used for shoe soles, then transparency is improved, but abrasion resistance deteriorates
Solution Approach 1:
The patent uses a composite material system combining polyisoprene (transparent rubber base) with polyoctenamer (transparent polymer with high abrasion resistance) and silica (reinforcing filler). This composite approach allows the material to simultaneously achieve transparency through refractive index matching and improved abrasion resistance through the reinforcing effects of polyoctenamer and silica, directly resolving the contradiction between transparency and abrasion resistance
Solution Approach 2:
The patent optimizes specific parameters including the refractive index of the rubber composition (1.510-1.530) to match transparent polymers, controls the vinyl content of polyisoprene (20-40 mol%) to balance transparency and mechanical properties, and adjusts the ratio of polyoctenamer (5-30 phr) to achieve the desired balance between abrasion resistance and transparency. These parameter changes enable simultaneous achievement of both transparency and abrasion resistance
2Strength
If carbon black and high amounts of additives are added to rubber composition, then mechanical properties are improved, but transparency deteriorates
Solution Approach 1:
The patent fundamentally changes the color/transparency characteristic by eliminating carbon black (which is black and opaque) and using instead transparent reinforcing agents like silica and polyoctenamer. This allows the rubber composition to maintain its transparency while still achieving the necessary mechanical strength through the transparent reinforcing system
Solution Approach 2:
The patent changes the composition parameters by limiting carbon black to 0-10 phr (compared to traditional high amounts) and introducing transparent alternatives. The refractive index of the final composition is controlled to be 1.510-1.530 to ensure transparency, while mechanical strength is maintained through the transparent polymer-polymer and polymer-filler interactions
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 composition achieves improved abrasion resistance, maintaining transparency and mechanical properties, making it suitable for sport shoes and other applications with reduced haze and increased total luminous transmittance, while meeting the requirements for sport shoes.
Implementation Method 1
comprising: from 35-60 wt. % of one or more synthetic isoprene polymers having a refractive index of between 1.500 to 1.525 at 23° C.; from 35-60 wt. % of one or more transparent polymers different from isoprene polymers wherein the difference between the refractive indices of component (a) and (b) is 0.100 or less
Data Source
AI summary
The present disclosure provides a solid curable transparent rubber composition containing one or more synthetic isoprene polymer, one or more transparent polymer, one or more curing agent, additives that do not influence transparency and one or more polyalkenamers. The solid curable transparent rubber composition, once cured, has a haze of less than 30% and a total light transmission of more than 80%. The disclosure further provides a cured transparent rubber composition made thereof, and a manufacturing process for the cured composition. The present disclosure also provides an article including the rubber composition, in particular shoes with transparent soles.