Polyolefin Rubber Sole Bonding via Semi-Curing
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Solution Overview
Problem
Conventional methods for manufacturing sole assemblies in athletic footwear face challenges in efficiently bonding polyolefin midsole and rubber outsole members, often requiring adhesives and resulting in suboptimal performance in terms of traction and ground reaction force attenuation.
Innovation Solution
A method using a mold assembly with specific recess configurations to preheat and partially cure the polyolefin and rubber separately, then fully cure and cross-link them together without adhesives, ensuring a strong bond and optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional methods are used to bond polyolefin midsole and rubber outsole members, then the bonding process is simpler, but the bond strength and performance are suboptimal
Solution Approach 1:
The patent changes the physical and chemical parameters of the polyolefin material by incorporating peroxide and using controlled heating to achieve semi-curing and subsequent full curing. This transforms the material from a simple thermoplastic to a cross-linked elastomeric structure that can form strong bonds with rubber without adhesives
Solution Approach 2:
The patent applies preliminary action by semi-curing the polyolefin midsole member before bonding it to the rubber outsole. This pre-treatment creates a reactive surface and internal structure that enables strong adhesion and cross-linking during the final curing stage, eliminating the need for separate adhesive applications
2Reliability
If adhesives are used to bond midsole and outsole members, then the bonding process is easier, but the traction and ground reaction force attenuation performance deteriorate
Solution Approach 1:
The patent extracts and eliminates the adhesive layer from the sole assembly construction. By using peroxide-crosslinked polyolefin that bonds directly to rubber through chemical cross-linking, the invention removes the intermediate adhesive substance while achieving superior bond strength and maintaining traction performance
Solution Approach 2:
The patent creates a composite material system where peroxide-modified polyolefin and rubber form a unified cross-linked network. This composite structure combines the advantages of both materials while achieving direct molecular-level bonding, eliminating the need for separate adhesive materials
3Manufacturing precision
If polyolefin and rubber are cured simultaneously, then the manufacturing process is simpler, but the bonding quality and cross-linking effectiveness deteriorate
Solution Approach 1:
The patent applies preliminary action by semi-curing the polyolefin midsole member before bonding it to the rubber outsole. This pre-treatment creates a reactive surface and internal structure that enables strong adhesion and cross-linking during the final curing stage, eliminating the need for separate adhesive applications
Solution Approach 2:
The patent segments the curing process into distinct stages: semi-curing of the polyolefin midsole, assembly with rubber outsole, and final full curing. This segmentation allows precise control over each stage's parameters, ensuring optimal cross-linking and bonding quality that simultaneous curing cannot achieve
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 method effectively bonds polyolefin and rubber members, enhancing traction and ground reaction force attenuation, while eliminating the need for adhesives and improving the overall durability and comfort of the sole assembly.
Implementation Method 1
The mold assembly is preheated and a quantity of rubber is placed in a first portion of the lower recess. The top plate, middle plate, and bottom plate are subjected to heat to semi-cure the rubber in the lower recess to form an outsole member.
Implementation Method 2
The top plate and bottom plate are subjected to heat such that the polyolefin expands within the sole recess and the polyolefin and rubber in the sole recess fully cure, cross-link, and bond to one another to form a sole assembly
Implementation Method 3
The top plate and bottom plate are subjected to heat such that the polyolefin expands within the sole recess and the polyolefin and rubber in the sole recess fully cure, cross-link, and bond to one another
Data Source
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AI summary
A sole assembly is formed by preheating a mold assembly, placing a quantity of rubber in a first portion of a lower recess of a mold assembly; placing a middle plate in contact with a bottom plate, and an upper plate in contact with the middle plate; subjecting the top, middle, and bottom plates to heat to semi-cure the rubber in the lower recess to form an outsole member; separating the top plate, the middle plate, and the bottom plate; placing the top plate in contact with the bottom plate, with polyolefin forming a midsole above the semi-cured rubber; subjecting the top and bottom plates to heat such that the polyolefin expands within the sole recess and the polyolefin and rubber in the sole recess fully cure, cross-link, and bond to one another to form a sole assembly; cooling the top and bottom plates; and removing the sole assembly.