Thermally Recyclable Flexible Polyurethane Foam
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Solution Overview
Problem
Current flexible polyurethane foams with standard free densities are chemically crosslinked, making them non-thermoplastically recyclable by fusion, limiting their application in products like footwear and consumer electronics, and they often have high densities that do not retain elastic properties or cushioning effectively.
Innovation Solution
A process for producing flexible polyurethane foam with a free density between 30 and 150 g/L by converting a reaction mixture comprising an isocyanate component with a functionality between 1.9-2.2, a polyol component with a functionality between 1.7-2.2, at least one blowing agent, and a catalyst, allowing for thermal recyclability and fusion processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flexible polyurethane foams are produced with standard polyol components of functionality between 2 and 8, then the foams achieve adequate cushioning and elastic properties, but they become chemically crosslinked and non-thermoplastically recyclable by fusion
Solution Approach 1:
The patent changes the functionality parameter of the polyol component from the standard range of 2-8 to a specific range of 1.7-2.2. This parameter change prevents chemical crosslinking while maintaining the desired cushioning and elastic properties, thereby enabling thermal recyclability by fusion without sacrificing mechanical performance
Solution Approach 2:
Instead of accepting crosslinking as an inevitable consequence of using polyols with functionality 2-8, the patent inverts the approach by deliberately selecting polyols with lower functionality (1.7-2.2) to avoid crosslinking entirely. This inversion allows the foam to remain thermoplastically recyclable while still achieving the required mechanical properties
2Strength
If flexible polyurethane foams are produced with higher densities, then the foams achieve adequate structural strength, but they lose elastic properties and cushioning effectiveness
Solution Approach 1:
The patent optimizes the density parameter to a specific range of 30-150 g/L, which balances structural strength with elastic properties and cushioning effectiveness. This density range, combined with the controlled polyol functionality, ensures both mechanical integrity and functional performance
3Object-generated harmful factors
If wastes comprising flexible polyurethane foams and thermoplastic materials are recycled, then environmental disposal problems are reduced, but the recycled material is not 100% thermoplastic and limits further applications
Solution Approach 1:
The patent applies preliminary action by designing the foam with specific polyol functionality (1.7-2.2) from the outset to ensure thermal recyclability. This preliminary design choice guarantees that the foam can be recycled by fusion and produce 100% thermoplastic recycled material that maintains full adaptability for further applications such as footwear, consumer articles, and technical products
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 resulting flexible polyurethane foam is thermally recyclable, enabling the production of valuable starting materials for injection-molded or extruded products with improved mechanical properties and reduced weight, suitable for applications in footwear, consumer electronics, and other industries.
Implementation Method 1
conversion of a reaction mixture comprising an isocyanate component having a functionality between 1.9-2.2; b. a polyol component having a functionality between 1.7-2.2
Implementation Method 2
c. at least one blowing agent
Implementation Method 3
d. a catalyst
Data Source
AI summary
The present invention relates to a process for producing a flexible polyurethane foam thermally recyclable by fusion, and to hybrid materials made of flexible polyurethane foam and compact thermoplastic elastomer and/or expanded thermoplastic polyurethane.