Multicolor ETPU Foamed Sole via Co-Extrusion
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Solution Overview
Problem
Foamed soles made from engineered thermoplastic polyurethane (ETPU) pellets often have dense grainy lines that cause discomfort and uneven color distribution due to the properties of ETPU pellets, leading to single-colored soles with aesthetic and functional limitations.
Innovation Solution
An injection molded integral multicolor thermoplastic elastomeric foamed sole is created by mixing, milling, and heating thermoplastic elastomeric raw materials of different colors with lubricants and foaming agents, followed by extrusion and co-extrusion processes to form layers of arbitrarily superposed injection strips, achieving a fully foamed, low-density sole with moderate hardness and improved color separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ETPU pellets are used for foamed soles, then the soles have good resilience and low density, but dense grainy lines appear on surfaces causing visual discomfort
Solution Approach 1:
The patent divides the homogeneous ETPU material into multi-colored granules with different colors and densities. These segmented granules are then distributed throughout the foam structure, creating a multi-layered composition that maintains the resilience benefits of ETPU while eliminating the uniform grainy line pattern through color variation and structural segmentation.
Solution Approach 2:
The patent applies different colors and material properties to different regions of the sole. By creating local variations in color, density, and granule composition across the sole structure, the patent eliminates the uniform visual defect of grainy lines while maintaining good resilience through strategic placement of different material properties in different zones.
2Ease of manufacture
If single forming process is used with multi-color ETPU pellets, then manufacturing is simplified, but uneven pellet distribution occurs causing poor color separation
Solution Approach 1:
The patent performs preliminary classification and sorting of multi-colored ETPU granules before the forming process. By pre-separating and organizing the granules according to color and density characteristics, the patent ensures uniform distribution during molding while maintaining the simplicity of the single-forming process, thus achieving both ease of manufacture and good color separation precision.
3Adaptability or versatility
If auxiliary sheets are attached to ETPU foamed soles to achieve multicolor and specialized functions, then aesthetic features and functions are enhanced, but manufacturing complexity and defect rates increase
Solution Approach 1:
The patent combines multiple functions and aesthetic features into a single integrated foaming process rather than requiring separate auxiliary sheets. By incorporating multi-colored granules, specialized functional materials, and structural variations directly into the ETPU foam matrix during one forming operation, the patent achieves enhanced adaptability while reducing manufacturing complexity and eliminating defects associated with multi-step assembly.
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 solution eliminates visual discomfort from grainy lines, provides a comfortable and aesthetically pleasing multicolor design, enhances resilience and shock absorption, and simplifies the manufacturing process while reducing defects and environmental impact.
Implementation Method 1
adding respectively gas foaming agents at 0.2%-10% of the thermoplastic elastomeric raw materials of the at least two color classifications, compressive injecting the gas foaming agents respectively into the thermoplastic elastomeric fused masses, fully mixing to form thermoplastic elastomeric gas foamed polymers
Implementation Method 2
mixing, milling and heating thermoplastic elastomeric raw materials of at least two color classifications, lubricants, and foaming auxiliaries to be thermoplastic elastomeric fused masses
Implementation Method 3
extruding respectively foaming strips of thermoplastic elastomeric gas polymers of the at least two color classifications with an extrusion and injection process
Data Source
AI summary
An injection molded integral multicolor thermoplastic elastomeric foamed sole, comprising an integral sole made from thermoplastic elastomeric foaming bodies of at least two colors, and on surfaces thereof are provided grains of arbitrarily superposed injection strips; the foamed sole is made by: mixing, milling and heating thermoplastic elastomer raw materials of at least two colors, lubricants, and foaming auxiliaries to be thermoplastic elastomeric fused-masses, adding respectively gas-foaming agents at 0.2%-10% of thermoplastic elastomeric raw materials, compressive injecting gas-foaming agents respectively into thermoplastic elastomeric fused-masses, fully mixing to form thermoplastic elastomeric gas foamed polymers, and extruding foaming strips of thermoplastic elastomeric gas polymers of the at least two colors with an extrusion and injection process and/or co-extruding the foaming strips of thermoplastic elastomeric gas polymers of the at least two colors by a co-extrusion process into molds to form arbitrarily superposed strips, clamp molds, discharge gas and form.