Leather Footwear Adhesive Bonding
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Solution Overview
Problem
Existing methods for manufacturing leather-based footwear struggle with creating strong, flexible, and cost-effective multilayered structures, often resulting in stiff constructions and high manufacturing costs due to complex layer patterns.
Innovation Solution
A method involving the use of a leather base layer and a leather attachment layer, bonded together with an intermediate application of adhesive, activated, and then cured under pressure, allowing for strong and robust bonding without stitching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If multiple layers of leather are used to create comfortable and insulating footwear, then the footwear provides better insulation and comfort, but the construction becomes stiff and more expensive
Solution Approach 1:
The patent replaces traditional mechanical stitching systems with a chemical adhesive bonding system. The adhesive layer chemically bonds leather layers together, providing both structural integrity and flexibility without the rigidity introduced by stitching holes and threads. This substitution allows multiple leather layers to move together as a unified flexible structure while maintaining insulation properties.
Solution Approach 2:
The patent introduces an adhesive layer as an intermediary substance between leather layers. This adhesive mediator creates strong bonds between layers while allowing them to flex and move relative to each other, preventing the stiffness that would result from direct mechanical fastening. The adhesive acts as a flexible bridge that maintains layer cohesion without restricting movement.
2Strength
If traditional stitching methods are used to bond leather layers, then the construction is strong, but the manufacturing becomes more complex and expensive
Solution Approach 1:
The patent replaces the complex mechanical stitching system (needles, threads, stitching machines) with a simpler chemical adhesive application system. The adhesive can be applied using rollers, brushes, or spray systems, eliminating the need for puncturing the leather and threading needles through multiple layers. This reduces manufacturing complexity while maintaining bonding strength.
Solution Approach 2:
The patent changes the bonding mechanism from mechanical (stitching) to chemical (adhesive curing). By controlling parameters such as adhesive application rate, drying time, and curing conditions, the process achieves strong bonds with simpler equipment. The chemical bonding process allows for continuous production without the stopping and starting required by mechanical stitching operations.
3Strength
If adhesive is applied between leather layers and then cured under pressure, then strong bonding is achieved, but the process requires additional time and energy
Solution Approach 1:
The patent utilizes phase transitions of the adhesive material to achieve bonding. The adhesive transitions from a liquid or semi-liquid application state to a solid bonded state through controlled drying and curing. This phase change process allows the adhesive to flow into contact surfaces during application, then solidify under pressure to create strong bonds, efficiently using energy only during the transition phases rather than continuous heating.
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 achieves a strong and flexible bonding of leather layers, capable of withstanding daily wear and tear, while also allowing for complex designs and reduced manufacturing costs by eliminating the need for stitching.
Implementation Method 1
fixing the leather base layer (LBL) and the leather attachment layer (LAL) against each other with an intermediate application of adhesive (A) between them
Implementation Method 2
curing the adhesive and thereby bonding the leather base layer (LBL) and the leather attachment layer (LAL) to each other
Implementation Method 3
subjecting the applied adhesive (A) to pressure and heat thereby forcing the leather base layer (LBL) and the leather attachment layer (LAL) against each other under a pressure P with the adhesive (A) between them while melting the adhesive (A)
Implementation Method 4
cooling the adhesive (A) thereby bonding the leather base layer (LBL) and the leather attachment layer (LAL) to each other
Data Source
AI summary
A method of manufacturing a footwear includes the steps of providing a leather base layer and providing a leather attachment layer. The leather base layer and the leather attachment layer are fixed against each other with an intermediate application of adhesive between them. The applied adhesive is activated. The leather base layer and the leather attachment layer are forced against each other under a pressure with the adhesive between them. The adhesive is cured and thereby the leather base layer and the leather attachment layer are bonded to each other. The bonded leather base layer and the leather attachment layer are integrated as part of the footwear.