Compressed PU Foam Insole Covering Without Adhesive Layers
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Solution Overview
Problem
Existing methods for applying covers to shoe insoles are complex, requiring additional adhesive layers and manufacturing steps, which increase costs and limit material selection and customization.
Innovation Solution
A method involving thermoplastic compression of a PU foam layer below its melting point to reduce thickness and enhance mechanical, orthopedic, and optical properties, allowing direct bonding to a RIM-PU foam base without adhesives, enabling customizable and cost-effective production of multi-layer shoe insoles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional adhesive methods are used to apply covers to shoe insoles, then the cover can be attached to the insole blank, but the manufacturing process becomes complex and costly due to additional adhesive layers and coating steps
Solution Approach 1:
The invention extracts and eliminates the adhesive layer from the manufacturing process. Instead of applying separate adhesive coatings to bond the cover to the insole blank, the patent uses a foamable composition that integrates the bonding function directly into the foam application step, thereby removing the complex adhesive application and drying steps.
Solution Approach 2:
The invention merges the cover attachment function with the foam application process. The foamable composition serves multiple functions simultaneously: it forms the cover layer, provides structural support, and creates the bonding interface with the insole blank, consolidating what were previously separate steps into one integrated process.
2Reliability
If adhesive coating is applied to the cover material to prevent contamination, then the cover material is protected, but additional manufacturing steps and costs are incurred
Solution Approach 1:
The foamable composition is self-protecting during application. The foam structure itself prevents contamination of the cover material surface, eliminating the need for separate protective coating steps. The expanding foam naturally shields the underlying material during the bonding process.
3Manufacturing precision
If the PU foam layer is thermoplastically compressed to reduce thickness, then the mechanical and optical properties are enhanced, but the foam structure may be damaged at high temperatures
Solution Approach 1:
The invention optimizes the thermal and pressure parameters of the compression process. By controlling the temperature to remain below the foam degradation threshold and adjusting pressure and time parameters, the process achieves precise thickness reduction while preserving the foam structure. The key is finding the optimal parameter window that enables compression without damage.
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 simplifies the production process, maintains the foam structure for enhanced properties like abrasion resistance and elasticity, and allows for customizable thickness and design, resulting in a durable, cost-effective, and comfortable shoe insole with improved grip and appearance.
Implementation Method 1
The PU foam layer is thermoplastically compressed in a press in such a way that the wall thickness is permanently reduced
Implementation Method 2
The PU foam layer is thermoplastically compressed below its melting point
Implementation Method 3
a PU foam layer is produced using the RIM process
Implementation Method 4
formed from isocyanate and polyol
Implementation Method 5
thermoplastic compression of a PU foam layer below its melting point to reduce thickness
Implementation Method 6
thermoplastically compressed in a press
Data Source
Figure 1a~1c
Figure 2~4
Figure 5~6
AI summary
A method for producing a top layer material for application to shoe insole blanks as a top layer and/or bottom layer, comprising the steps of: i) manufacturing a PU foam layer using the RIM process; ii) thermoplastically pressing the PU foam layer in a press such that the wall thickness of the foam layer is permanently reduced. A shoe insole covered with such a top layer material, and a method for applying such a top layer material to a shoe insole, in particular to a RIM PU foam shoe insole.