Polyurethane Foam Thermal Conductivity and Stability

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Solution Overview

Problem

Existing polyurethane foams used for insulation, such as pipe insulation, face challenges in achieving a balance between low thermal conductivity and thermal stability, with prior art often compromising on one aspect at the expense of the other.

Innovation Solution

A polyurethane foam is developed by reacting polyether polyols, polyester polyols, and polyisocyanates in the presence of specific catalysts and blowing agents, with a controlled ISO index of 145 to 165, to achieve a balanced profile of low thermal conductivity and thermal stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional polyurethane foam formulations are used to reduce thermal conductivity, then insulation performance improves, but thermal stability deteriorates

Engineering Contradiction:
Improvethermal conductivityVSAvoidthermal stability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the ISO index (isocyanate index) within the range of 145-165, which represents a deviation from conventional formulations. This specific parameter range optimizes the balance between thermal conductivity and thermal stability, allowing the foam to achieve lower thermal conductivity while maintaining adequate thermal stability through controlled crosslinking density and cell structure formation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials by formulating a multi-component polyol system that includes polyether polyols, polyester polyols, and amino polyether polyols in specific proportion ranges. This composite polyol formulation creates a heterogeneous foam structure with differentiated cell walls and matrices that simultaneously provide thermal insulation properties and thermal stability, resolving the contradiction between these two properties.

Inventive Principle:
Principle #40Composite materials

2Loss of energy

If polyol composition is optimized for low thermal conductivity, then insulation efficiency improves, but foam structure stability worsens

Engineering Contradiction:
Improvethermal insulation efficiencyVSAvoidfoam structure stability
Core Design Contradiction:
Loss of energyVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by creating a differentiated foam structure where different polyol components concentrate in specific regions. The polyether polyols, polyester polyols, and amino polyether polyols distribute non-uniformly within the foam matrix, creating local variations in cell wall composition and density. This local heterogeneity provides both low thermal conductivity pathways and structural stability zones throughout the foam.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by controlling the proportion ranges of each polyol component (polyether polyol: 20-60 wt%, polyester polyol: 20-60 wt%, amino polyether polyol: 10-40 wt%) and the ISO index (145-165). These parameter optimizations create a foam structure that balances insulation efficiency and structural stability through controlled cell morphology and wall thickness distribution.

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 solution results in a polyurethane foam with significantly improved thermal insulation properties, maintaining thermal stability while reducing thermal conductivity, making it suitable for efficient pipe insulation.

Implementation Method 1

reacting at least one polyether polyol as component (A)... at least one polyester polyol as component (C) and at least one polyisocyanate as component (D)

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

in the presence of at least one catalyst selected from the group consisting of salts of carboxylic acids with 1 to 20 carbon atoms, amine-containing compounds and mixtures thereof as component (E)

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 3

at least one blowing agent as component (F)

Methodology Applied
Scientific EffectPhase Change: Phase Change

Implementation Method 4

The solution results in a polyurethane foam with significantly improved thermal insulation properties, maintaining thermal stability while reducing thermal conductivity

Methodology Applied
Scientific EffectThermal Insulation: Thermal Insulation

Data Source

PatentEP2688933B1Pu rigid foam with low thermal conductivity and good thermal stability
Publication Date: 2015.05.13 BASF SE

AI summary

The invention relates to a polyurethane foam that can be obtained by reacting at least one polyether polyol as component (A), at least one polyether polyol based on at least one amine as component (B), at least one polyester polyol as component (C), and at least one polyisocyanate as component (D), in the presence of at least one catalyst selected from the group consisting of salts of carboxylic acids with 1 to 20 C atoms, compounds containing amines, and mixtures thereof, as component (E), and at least one blowing agent as component (F), with the ratio of OCN groups to OH groups (ISO index) being between 140 and 180. In addition, the present invention relates to a method for producing this polyurethane foam, to the use of same for insulation, particularly for pipe insulation, and to a pipe insulator containing a polyurethane foam according to the invention.