Polyurethane Foam Recycling by TPU Extrusion Blending
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Solution Overview
Problem
Existing methods for recycling polyurethane foams, such as chemical recycling and thermal reprocessing, are costly and result in poor mechanical properties due to the use of catalysts and solvents, making it challenging to effectively reuse post-consumer or scrap polyurethane foams.
Innovation Solution
A solvent-free method involving shredding polyurethane foam and blending it with a thermoplastic polymer urethane thermoplastic elastomer at elevated temperatures to produce a recycled polyurethane product, utilizing a weight ratio exceeding 25:75 and temperatures of at least 180°C, without the need for catalysts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If chemical recycling methods using catalysts and solvent swelling are used to recycle thermoset polyurethane waste, then the polyurethane can be reprocessed, but the complexity and cost of the recycling process increases
Solution Approach 1:
The invention extracts and eliminates the need for catalysts and solvents from the recycling process by using mechanical grinding to reduce polyurethane foam to fine particles, which are then directly mixed with thermoplastic polyurethane elastomer and processed through extrusion. This removes the complex chemical processing steps while maintaining reprocessability.
Solution Approach 2:
The invention replaces chemical recycling methods (using catalysts and solvents) with a mechanical approach. The polyurethane foam is mechanically ground into fine particles and physically mixed with thermoplastic polyurethane elastomer, which is then processed through mechanical extrusion. This mechanical substitution eliminates the need for chemical catalysts and solvents, reducing process complexity and cost.
2Ease of manufacture
If thermal reprocessing of polyurethane foams is used by impregnating with catalyst through solvent swelling or direct mixing, then the carbamate exchange reactions can be facilitated, but the mechanical properties of the resultant product become poor
Solution Approach 1:
The invention extracts and eliminates the need for catalysts from the process. Instead of using catalysts to facilitate carbamate exchange reactions, the invention mechanically grinds polyurethane foam into fine particles and physically mixes it with thermoplastic polyurethane elastomer, which maintains good mechanical properties in the final product.
Solution Approach 2:
The invention creates a composite material by mechanically mixing ground polyurethane foam particles with thermoplastic polyurethane elastomer. This composite approach allows the recycled polyurethane to maintain its structural integrity and mechanical properties while being incorporated into new products, avoiding the degradation that occurs with catalytic thermal reprocessing.
3Productivity
If conventional recycling methods are used for polyurethane foams, then the materials can be recycled, but environmental impact increases due to solvent and catalyst usage
Solution Approach 1:
The invention extracts and eliminates harmful substances (catalysts and solvents) from the recycling process. The method uses only mechanical grinding and physical mixing, followed by extrusion processing, which produces no harmful chemical byproducts and eliminates the environmental hazards associated with catalyst and solvent usage in conventional recycling methods.
Solution Approach 2:
The invention replaces chemical recycling methods with a mechanical system. By using mechanical grinding to reduce polyurethane foam to fine particles and physical mixing with thermoplastic polyurethane elastomer, the process eliminates the need for catalysts and solvents, thereby reducing environmental impact while maintaining recycling capability.
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 recycled polyurethane products with acceptable mechanical properties suitable for various consumer applications, reducing environmental impact and production costs.
Implementation Method 1
The plurality of polyurethane masses are blended with the thermoplastic polymer urethane thermoplastic elastomer at an elevated temperature to produce a recycled polyurethane product
Data Source
AI summary
A polyurethane foam product is formed into a plurality of polyurethane masses. The plurality of polyurethane masses are fed into an extruder with a thermoplastic polymer urethane thermoplastic elastomer. The plurality of polyurethane masses are blended with the thermoplastic polymer urethane thermoplastic elastomer at an elevated temperature to produce a recycled polyurethane product. The weight ratio of the plurality of polyurethane masses to the thermoplastic polymer urethane thermoplastic elastomer exceeds about 50:50.