Fabric-Backed Adhesive Composite for Rubber Outsole Bonding
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Solution Overview
Problem
Existing adhesive technologies face challenges in effectively bonding rubber shoe outsoles to various materials like EVA due to their different properties, leading to inefficiencies, material sourcing issues, and the need for toxic solvent-based adhesives.
Innovation Solution
A method involving vulcanization of a rubber outsole with a fabric, where the rubber permeates into the fabric, creating a direct bond without the need for adhesives, and a water-based adhesive is applied to the fabric or a barrier layer for attachment to shoe uppers/midsoles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional adhesives are used to bond rubber outsoles to EVA or other materials, then bonding can be achieved, but the adhesive does not bond well due to different material properties (nonpolar rubber vs polar EVA)
Solution Approach 1:
A fabric layer is introduced as an intermediary between the rubber outsole and the adhesive. The fabric serves as a mediator that the adhesive can effectively bond to, while the rubber permeates into the fabric structure. This intermediary layer resolves the incompatibility between nonpolar rubber and polar adhesives by providing a surface that the adhesive can adhere to reliably.
Solution Approach 2:
The invention creates a composite structure consisting of rubber, fabric, and adhesive layers. This composite material system combines the advantages of each component: the rubber provides outsole functionality, the fabric provides a bonding interface, and the adhesive provides strong attachment to various materials. The composite structure enables universal adaptability to different materials including EVA, leather, and synthetic fabrics.
2Reliability
If multiple different adhesives are used to accommodate different material combinations, then bonding reliability improves, but device complexity and manufacturing efficiency deteriorate
Solution Approach 1:
The fabric-layer composite structure provides a universal bonding interface that works with a single type of adhesive across multiple material combinations. Instead of requiring different adhesives for rubber-to-EVA, rubber-to-leather, and rubber-to-synthetic fabric bonds, the fabric intermediary enables one adhesive type to reliably bond to all these material combinations, simplifying the adhesive system while maintaining bonding reliability.
3Strength
If solvent-based adhesives are used to achieve strong bonding, then bonding strength improves, but harmful factors increase due to toxicity and environmental pollution
Solution Approach 1:
The invention converts the challenge of material incompatibility into a benefit by using the fabric's physical structure (porosity, surface area) to enhance adhesive bonding. This allows water-based or environmentally friendly adhesives to achieve strong bonding through increased surface area contact and mechanical interlocking with the fabric, eliminating the need for toxic solvents while maintaining or improving bonding strength.
4Adaptability or versatility
If a fabric layer is added to the outsole composite, then adaptability to different materials improves, but manufacturing complexity increases
Solution Approach 1:
The fabric layer is merged with the rubber outsole through permeation and co-vulcanization, creating an integrated composite structure rather than separate layers. The rubber permeates into the fabric during molding and vulcanization, forming a unified structure where the fabric and rubber are mechanically interlocked. This merging reduces manufacturing complexity compared to assembling separate components, as the fabric-rubber-adhesive composite can be molded as a single integrated unit.
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 approach allows for universal adhesion of rubber outsoles to a variety of materials, reducing the need for multiple adhesives and materials, lowering costs, and ensuring a strong, durable bond without toxic chemicals.
Implementation Method 1
the rubber permeates into the fabric and then during vulcanization, the rubber is bonded directly to the fabric
Implementation Method 2
The rubber is then vulcanized in the mold with the fabric material in the mold. This causes the rubber to seep or otherwise permeate into the fabric and then during vulcanization, the rubber is bonded directly to the fabric
Data Source
AI summary
An adhesive composition for use in a shoe outsole assembly, and methods of forming the same are provided. In one aspect, the adhesive composition has a fabric layer with an adhesive applied to a top surface. In another aspect, the adhesive composition has a fabric layer with a barrier layer applied to a top surface, and an adhesive is applied to the barrier layer opposite to the fabric layer. The shoe outsole formed using the adhesive composition has the fabric material directly bonded with the outsole material such that the outsole material partially penetrates into the fabric. An adhesive is applied to the opposite side of the fabric or to the optional barrier layer which is on the opposite side of the fabric. This adhesive may then be used to bond the outsole to a shoe, such as a shoe upper, shoe midsole, and the like.