Polyurethane Foam Surface Shrinkage with HFO Foaming Agent

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Solution Overview

Problem

The use of hydrofluoroolefin (HFO) as a foaming agent in polyurethane foam formation leads to surface shrinkage, resulting in inferior surface smoothness and quality of the formed article.

Innovation Solution

Incorporating a compound represented by Formula 1: RO(CH2CH2O)n, where R is a C1 to C3 linear or branched alkyl and n is an integer of 1 or more, in the polyurethane foam composition containing HFO as a foaming agent, along with a polyether polyol and controlled polyisocyanate index, to stabilize the foam and enhance surface smoothness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If hydrofluoroolefin (HFO) is used as a foaming agent in polyurethane foam formation, then global warming potential is reduced, but surface smoothness deteriorates due to surface shrinkage

Engineering Contradiction:

Improveglobal warming potentialVSAvoidsurface smoothness

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

A surfactant is introduced as an intermediary substance to mediate between the HFO foaming agent and the polyurethane matrix. The surfactant prevents surface shrinkage caused by HFO by stabilizing the foam cell structure during expansion, thereby maintaining surface smoothness while allowing the use of HFO as the environmentally friendly foaming agent

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The concentration of the surfactant in the composition is optimized to specifically counteract the surface shrinkage effect of HFO. By adjusting the surfactant concentration parameter, the foam expansion and surface formation process is controlled to prevent shrinkage while maintaining the low global warming potential benefit of using HFO

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If HFO is used as a foaming agent, then chemical stability is reduced (lower global warming potential), but surface quality deteriorates due to shrinkage

Engineering Contradiction:

Improveglobal warming potentialVSAvoidsurface quality

Core Design Contradiction:

Object-affected harmful factorsVSShape

Solution Approach 1:

The surfactant acts as a mediator that interacts with HFO to stabilize the foam structure during the foaming process. This intermediary substance prevents the surface shrinkage that would otherwise occur due to HFO's chemical properties, thereby maintaining surface quality while preserving the environmental benefit of using HFO

Inventive Principle:

Principle #24Intermediary (Mediator)

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 composition achieves a polyurethane foam with excellent surface quality and smoothness, addressing the shrinkage issue caused by HFO, and forms a suitable thermal insulating material with improved properties.

Implementation Method 1

a composition for forming a polyurethane foam, wherein the composition contains a polyol, a polyisocyanate, and a foaming agent

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Implementation Method 2

to cause foaming

Methodology Applied

Scientific EffectFoaming: Foam

Data Source

PatentEP4229108B1Composition for forming polyurethane foam, polyurethane foam, and thermal insulating material

Publication Date: 2024.09.04 COVESTRO DEUTSCHLAND AG

AI summary

Provided is a composition for forming a polyurethane foam having excellent surface quality of a formed article, in particular, a polyurethane foam having excellent smoothness. The invention is a composition for forming a polyurethane foam, in which the composition comprises a hydrofluoroolefin as a foaming agent; and the composition comprises 0.2 to 6 parts by mass of at least one compound represented by Formula 1 relative to 100 parts by mass of the composition: RO(CH2CH2O)nR (Formula 1) where R is a C1 to C3 linear or branched alkyl, and n is an integer of 1 or more.