Polyurethane Polyol Blends Stabilized by Ester Additives
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Solution Overview
Problem
Thermosetting foam blends incorporating hydrochlorofluoroolefin blowing agents face stability issues and foam collapse due to the inherent chemical instability of these materials, leading to reduced shelf life and quality of the resultant foams.
Innovation Solution
The addition of an ester to the thermosetting foam blends stabilizes the composition over time, enhancing the shelf life and foam characteristics, resulting in foams with a uniform cell structure and minimal collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If hydrochlorofluoroolefin blowing agents are used to replace HFCs, then environmental performance is improved (zero ODP, low GWP), but chemical stability deteriorates leading to reduced shelf life and foam collapse
Solution Approach 1:
A stabilizer compound is introduced as an intermediary substance between the hydrochlorofluoroolefin blowing agent and the polyol premix. This stabilizer prevents direct harmful interactions, maintains chemical stability during storage, and allows the environmentally beneficial blowing agent to function properly without causing foam collapse or degradation
Solution Approach 2:
The chemical composition parameters of the polyol premix are modified by adding specific stabilizer compounds. This changes the chemical stability parameter of the system, enabling the premature mixture to remain stable during storage while still allowing the hydrochlorofluoroolefin to perform its blowing function effectively
2Loss of time
If polyol premix is aged prior to treatment with polyisocyanate, then processing time is reduced, but foam quality deteriorates and collapse occurs
Solution Approach 1:
The stabilizer compound is added in advance to the polyol premix during formulation, before any aging or storage occurs. This preliminary stabilization action ensures that even if the premix is aged or stored for extended periods before mixing with polyisocyanate, the chemical stability is maintained and foam quality is preserved
Solution Approach 2:
The stabilizer acts as a protective cushion against chemical degradation that would normally occur during aging or storage of the polyol premix. By providing this protective effect in advance, the system can tolerate longer storage times without compromising foam quality or causing collapse
Data Source
AI summary
The present invention is directed towards a method of stabilizing thermosetting foam blends such as polyurethane poly blends containing a blowing agent with negligible (low or zero) ozone-depletion and low GWP based upon unsaturated halogenated hydroolefins in which one or more ester is added to the thermosetting foam blends. The thermosetting foam blends typically in clued: polyol(s); surfactant(s); catalyst(s); flame retardent(s); organic acid inhibitor(s)/stabilizer(s); carbon dioxide generating agent(s). The addition of the one or more esters to the thermosetting foam blends was unexpectedly found to result in blends which were stable over time and the resulted foams have a uniform cell structure with little or no foam collapse.