Rigid Polyurethane Foam Insulation Shelf-Life Stability

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Solution Overview

Problem

Existing rigid polyurethane foam-forming compositions face challenges with shelf-life issues, poor foam structure, and flammability when using halogenated hydroolefins as blowing agents, particularly in applications requiring long storage and high thermal insulation properties.

Innovation Solution

A rigid foam-forming composition comprising a diisocyanate and/or polyisocyanate, an isocyanate-reactive component with a polyol blend, a halogenated olefin as a blowing agent, water, a surfactant, and a tertiary amine catalyst composition, which provides improved stability, adhesion, and thermal insulation while minimizing ozone depletion and global warming potential.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If hydrohaloolefins are used as blowing agents in rigid polyurethane foam, then ozone depletion potential is reduced and global warming potential is lowered, but shelf-life of the B-side composition deteriorates and foam structure quality worsens

Engineering Contradiction:
Improveozone depletion potentialVSAvoidshelf-life of B-side composition
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the catalyst system by selecting specific tertiary amines (triethylamine, triisopropylamine, or trimethylamine) with controlled reactivity toward hydrohaloolefins. This parameter change allows the use of environmentally friendly blowing agents while maintaining acceptable shelf-life through optimized catalytic activity levels.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite catalyst system combining tertiary amines with specific ratios of other catalysts (metal soaps, organometallic compounds) to achieve balanced performance. This composite approach allows the tertiary amine to protect against hydrohaloolefin decomposition while other catalysts maintain foam formation efficiency.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If hydrohaloolefins are used as blowing agents, then environmental properties improve, but foam structure quality and stability deteriorate due to catalyst-blowing agent reactions

Engineering Contradiction:
Improveglobal warming potentialVSAvoidfoam structure quality
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The tertiary amine catalyst acts as an intermediary that selectively interacts with hydrohaloolefins to prevent their premature decomposition. It mediates between the blowing agent stability requirement and the need for controlled foam formation, protecting the blowing agent during storage while allowing controlled reaction during foaming.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent optimizes the concentration and type of tertiary amine catalyst to control its reactivity with hydrohaloolefins. By adjusting these parameters, the system achieves sufficient blowing agent stability during storage while maintaining adequate reactivity during the actual foaming process to produce high-quality foam structure.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If water is used as a blowing agent component, then thermal insulation properties improve, but gel time becomes unstable after long storage periods

Engineering Contradiction:
Improvethermal insulation propertiesVSAvoidgel time stability
Core Design Contradiction:
TemperatureVSDuration of action of stationary object

Solution Approach 1:

The patent adjusts the catalyst system parameters (type and amount of tertiary amine, metal soap, and organometallic catalyst) to compensate for the gradual consumption of water and changes in composition that occur during long-term storage. This parameter optimization ensures consistent gel time performance both immediately after mixing and after extended storage periods.

Inventive Principle:
Principle #35Parameter changes

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 stable foam structure with enhanced thermal insulation, long shelf life, low shrinkage, and excellent adhesion to facer substrates, making it suitable for refrigerated trailer floor insulation without generating high pressure during foaming.

Implementation Method 1

They are produced by reacting an appropriate polyisocyanate and an isocyanate-reactive compound, usually a polyol, in the presence of a blowing agent.

Methodology Applied
Scientific EffectGas generation from blowing agent:

Implementation Method 2

They are produced by reacting an appropriate polyisocyanate and an isocyanate-reactive compound, usually a polyol, in the presence of a blowing agent.

Methodology Applied
Scientific EffectChemical reaction between water and isocyanate:

Implementation Method 3

The thermal insulating properties of closed-cell rigid foams are dependent upon a number of factors, including the average cell size and the thermal conductivity of the contents of the cells.

Methodology Applied
Scientific EffectThermal insulation through closed-cell structure: Thermal Insulation

Data Source

PatentEP3784709B1Rigid polyurethane foams suitable for use as panel insulation
Publication Date: 2025.02.19 COVESTRO LLC

AI summary

Disclosed are polyurethane-foam forming compositions, rigid polyurethane foams and methods for their production, as well as to composite articles comprising such foams sandwiched between facer substrates, including use of such composite elements for floor insulating elements for refrigerated tractor trailers. The rigid polyurethane foams are produced from an isocyanate-reactive component comprising: (1) a polyol blend; (2) a halogenated hydroolefin; (3) a surfactant; (4) water; and (5) a tertiary amine catalyst composition.