Footwear Outsole Fabric Attachment via Molten Plastic Interlayer
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Solution Overview
Problem
The fabric layer in footwear soles often peels off due to wear and tear, as the adhesive used to attach it to the EVA-based sole fails to provide a secure bond.
Innovation Solution
A method involving a foam material with a fabric layer adhered to it using a molten plastic layer, where heat pressing ensures the plastic flows and contacts the foam material, dispelling air and increasing contact area, resulting in a strong adhesive bond between the fabric, plastic, and foam material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive is used to attach fabric to the outsole surface, then the fabric can be attached to the sole, but the fabric peels off as the sole is worn and the adhesive gives way to wear and tear
Solution Approach 1:
A layer of plastic is introduced as an intermediary material between the fabric and the foam outsole. This plastic layer acts as a mediator that bonds to both the fabric and the foam material, creating a more durable attachment system than adhesive alone. The plastic layer distributes mechanical stresses and prevents direct failure at the fabric-adhesive interface.
Solution Approach 2:
The invention uses a composite structure consisting of fabric, plastic layer, and foam material. This multi-material construction combines the advantages of each material: the fabric provides surface coverage and aesthetics, the plastic provides strong bonding and structural integrity, and the foam provides cushioning and support. The composite structure resists peeling and wear better than single-material constructions.
2Strength
If heat pressing is applied to melt plastic and adhere fabric to foam material, then strong bonding is achieved, but energy and time are required for heating and pressing
Solution Approach 1:
The plastic layer undergoes a phase transition from solid to molten state during heat pressing, allowing it to flow and conform to the foam material surface. Upon cooling, it solidifies and forms a strong bond. This phase change enables effective bonding while using a relatively simple and energy-efficient heat pressing process.
Solution Approach 2:
The heat pressing process temporarily changes physical parameters (temperature and pressure) to enable bonding, then returns them to normal conditions. The temperature is raised to melt the plastic, pressure is applied to ensure contact, and then both are reduced to solidify the bond. This controlled parameter change achieves strong bonding without excessive energy consumption.
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 secures the fabric to the foam material, enhancing durability and preventing peeling, with the molten plastic solidifying to form a strong adhesive contact, even after cooling and potential cold pressing for additional bonding.
Implementation Method 1
the plastic melts under heat and the molten plastic flows over the surface of the foam material
Implementation Method 2
the heat expands any air between the foam material and dispels some of the air from between the layers of fabric-plastic-foam material
Implementation Method 3
On cooling, the thermoplastic solidifies and adheres the layers of fabric, plastic and foam material together
Implementation Method 4
the plastic is a thermoset material which can be heat cured to bind to the fabric and to the foam material
Data Source
AI summary
The sole of a footwear such as slipper having an outsole. The sole is made of a foam material and outsole area of which is partly laid with a fabric material. The fabric is attached to the outsole layer by a plastic which has been heat pressed to the fabric and the foam material. This provides a strong attachment between the fabric-plastic-foam material.