Recycled Polyurethane Foam Earplugs with Dispersant Mixing
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Solution Overview
Problem
The production of polyurethane foam earpieces using recycled pulverized polyurethane foam (RPPF) is hindered by challenges such as maintaining suspension, pumping and mixing difficulties, incompatibility with conventional foam, uncleanliness, and maintaining critical properties like sound attenuation and comfort.
Innovation Solution
Incorporating a percentage of clean recycled pulverized polyurethane foam (RPPF) into the base formula, mixing it with isocyanates, and curing the blend in molds to create flexible polyurethane foam earpieces that maintain or improve sound attenuation, comfort, and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If recycled pulverized polyurethane foam (RPPF) is incorporated into the base formula, then cost-effectiveness and biodegradability are improved, but manufacturing difficulties arise including suspension maintenance, pumping and mixing challenges
Solution Approach 1:
The patent introduces a dispersant as an intermediary substance to facilitate the incorporation of RPPF particles into the polyol mixture. The dispersant acts as a mediator that reduces particle aggregation, improves suspension stability, and enables smooth pumping and mixing operations, thereby resolving the manufacturing difficulties while maintaining cost-effectiveness
2Stability of the object's composition
If RPPF is used in the foam formulation, then material compatibility and cleanliness are improved, but maintaining critical properties like sound attenuation and comfort becomes difficult
Solution Approach 1:
The patent systematically optimizes several parameters including RPPF particle size distribution, concentration levels in the formulation, dispersant dosage, and mixing conditions. By adjusting these parameters, the patent achieves both material compatibility and consistent sound attenuation properties, resolving the contradiction between compatibility and property consistency
3Ease of manufacture
If the isocyanate component is reduced to lower cost, then cost-effectiveness is improved, but foam performance and reliability may deteriorate
Solution Approach 1:
The patent recovers and utilizes RPPF particles that would otherwise be waste materials, incorporating them into the foam formulation. This allows for reduced isocyanate content while maintaining foam performance through the reinforcing effect of the RPPF particles, thereby achieving cost-effectiveness without sacrificing reliability
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 allows for cost-effective production of earpieces with equivalent or improved properties to standard polyurethane foam, including sound attenuation and comfort, while reducing the higher-cost isocyanate component and enhancing biodegradability and recyclability.
Implementation Method 1
Current art for the production of molded flexible polyurethane foams consist of mixing isocyanates (A-side) with isocyanate-reactive hydrogen-containing compounds (B-side) in the presence of a foaming agent such as water or carbon dioxide. The resulting exothermic reaction produces flexible polyurethane foam.
Implementation Method 2
mixing isocyanates (A-side) with isocyanate-reactive hydrogen-containing compounds (B-side) in the presence of a foaming agent such as water or carbon dioxide. The chemicals react and expand into foam
Data Source
AI summary
An earpiece of flexible foam construction which incorporates recycled pulverized polyurethane foam (RPPF). RPPF constituting 5% to 30% of the improved foam has been found to be useful. The novel and unique nature of RPPF allows for the replacement of a higher cost component with a lower cost component while maintaining or improving physical properties, such as sound attenuation, sound control, comfort and fit.