Polyurethane Foam Resiliency via Reaction Injection Molding
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Solution Overview
Problem
Compression molding of polyurethane foam articles results in non-uniform density and reduced flexibility and resiliency due to areas of greater compression, compromising the desired properties of cushioning and apparel applications.
Innovation Solution
A method involving reaction injection molding using a combination of polyol, isocyanate, and polyurethaneurea aqueous dispersion, with a chain extender and blowing agent, to form polyurethane foam with improved resiliency, elasticity, and resistance to compression, ensuring uniform properties across the article.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If compression molding is used to prepare shaped polyurethane foam articles, then the desired shape and form are achieved, but the density becomes non-uniform and flexibility and resiliency are reduced
Solution Approach 1:
Instead of molding solid foam blocks under compression, the invention inverts the approach by injecting liquid polyol and isocyanate compositions into the mold cavity where they react and expand in situ to form the foam directly in the desired shape, eliminating compression-induced density non-uniformity
Solution Approach 2:
The invention uses reaction injection molding where liquid compositions are injected under pressure into the mold, and the chemical reaction generates gas expansion to form the foam structure, utilizing fluid dynamics and pressure control to achieve uniform density throughout the shaped article
2Shape
If compression molding is used to prepare shaped polyurethane foam articles, then the desired shape is achieved, but flexibility and resiliency are compromised due to areas of greater compression
Solution Approach 1:
The invention inverts the manufacturing approach by forming the foam in situ through chemical reaction rather than compressing pre-formed blocks, thereby preserving the inherent flexibility and resiliency of the foam material while achieving the desired shape
Solution Approach 2:
The invention changes the fundamental parameters of the molding process by using chemical reaction and expansion instead of mechanical compression, which maintains the foam's cellular structure and mechanical properties while achieving the required shape
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 enhances the flexibility and resiliency of polyurethane foam articles by maintaining consistent density and properties throughout, overcoming the limitations of compression molding.
Implementation Method 1
mixing the first composition and the second composition to form a reaction mixture into a heated mold; and allowing the reaction mixture to form a polyurethane foam
Implementation Method 2
the blowing agent includes a polyurethaneurea aqueous dispersion which comprises: a polymer which is the reaction product of: (1) at least one polyol selected from polyethers, polyesters, polycarbonates, and combinations thereof
Data Source
AI summary
The present invention provides a method for preparing a foam that includes a polyurethaneurea dispersion. These foams have enhanced flexibility and resistance to compressibility compared to convention polyurethane foam. These foams may also be made by a reaction injection molding process. The method includes preparing a shaped polyurethane foam article by: (a) providing a first composition comprising at least one polyol, a chain extender composition and a blowing agent; (b) providing a second composition comprising at least one of a diisocyanate, a capped glycol, and combinations thereof; (c) mixing the first composition and the second composition to form a reaction mixture into a heated mold; and (d) allowing the reaction mixture to form a polyurethane foam; wherein the first composition includes one of: (i) the chain extender composition includes at least one amine compound; (ii) the blowing agent includes a polyurethaneurea aqueous dispersion; and (iii) combinations of (i) and (ii).