Supercritical CO2 Foamed Polyurethane Insulation
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Solution Overview
Problem
Existing methods for producing insulation bodies based on rigid polyurethane/polyisocyanurate (PUR/PIR) foams face challenges such as long processing times and the inability to consistently achieve fine-celled and high open-cell content foams with low thermal conductivity.
Innovation Solution
A process involving the injection of a polyurethane reactive mixture containing supercritical CO2 into a pressurized mold, followed by rapid decompression and curing, with subsequent application of a vacuum to produce insulation bodies with high open-cell content and small cell sizes, utilizing a barrier film for gas-tightness and incorporating a gas scavenger material to bind residual gases and moisture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to produce rigid PUR/PIR foams, then the foam structure can be formed, but the processing time is excessively long and fine-celled structure with high open-cell content cannot be consistently achieved
Solution Approach 1:
The patent changes the physical state of CO2 from gaseous to supercritical by increasing pressure and temperature parameters. This supercritical state allows CO2 to penetrate the polymer matrix more effectively and form uniform fine cells during rapid decompression, achieving >90% open-cell content with cell diameters <180 μm while reducing processing time to 1-40 seconds
Solution Approach 2:
The patent performs preliminary saturation of the polyurethane reactive mixture with supercritical CO2 before mold injection. This pre-loading of CO2 ensures that sufficient gas is available during the subsequent rapid decompression to create the desired fine-celled open-cell structure without requiring extended processing times
2Reliability
If the foam is evacuated to achieve low thermal conductivity, then insulation performance improves, but gas permeability of the foam structure limits the effectiveness of evacuation
Solution Approach 1:
The patent creates a controlled porous structure with >90% open-cell content and small cell sizes (。<180 μm) that facilitates efficient gas evacuation. The uniform fine-cell structure provides numerous small pathways for gas removal while the subsequent application of vacuum effectively evacuates these pores, achieving low thermal conductivity despite the inherently high gas permeability of open-cell foams
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
This process enables the production of insulation bodies with an open-cell content of >90% and cell diameters <180 μm, achieving low thermal conductivity and reducing processing time, thereby addressing the limitations of prior art.
Implementation Method 1
A process involving the injection of a polyurethane reactive mixture containing supercritical CO2 into a pressurized mold
Implementation Method 2
WO 2011/054868 A and WO 2011/054873 A disclose production processes for fine- and closed-cell urethane-containing foams using CO2 as a supercritical blowing agent. The production of a microemulsion from the polyol phase and supercritical CO2 is in each case decisive for the success of the process.
Implementation Method 3
The sudden decompression of CO2-containing reaction mixtures is described in WO 2001/98389 A1. This patent application relates to a process for producing polyurethane block foam, wherein a carbon dioxide-containing polyurethane reactive mixture is suddenly decompressed from a pressure above the equilibrium solution pressure of the carbon dioxide to standard pressure.
Implementation Method 4
The liquid polyurethane reactive mixture is foamed by the liberation of dissolved carbon dioxide and the foamed mixture is applied to a substrate and subsequently cured to afford block foam.
Implementation Method 5
a barrier material which attenuates gas permeability and envelops the open-celled rigid PUR/PIR foam
Implementation Method 6
subsequent application of a vacuum to produce insulation bodies with high open-cell content and small cell sizes
Implementation Method 7
incorporating a gas scavenger material to bind residual gases and moisture
Data Source
AI summary
The present invention relates to an insulation body based a hard, fine-cell and open-cell polyurethane/polyisocyanurate foam with a barrier film, and a method for producing same.