Polyisocyanurate Foam Blowing Agent Mixture for Low Thermal Conductivity
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Solution Overview
Problem
Current methods for producing rigid polyisocyanurate foams face challenges in achieving high compressive strength, low thermal conductivity, and excellent surface quality while minimizing the use of ozone-depleting and greenhouse gas emissions, as well as avoiding the deterioration of mechanical properties and storage stability issues with existing blowing agents.
Innovation Solution
A process involving aromatic polyisocyanate, isocyanate-reactive compounds with a high number-average content of isocyanate-reactive hydrogen atoms, a specific blowing agent mixture of aliphatic, halogenated hydrocarbon compounds, and hydrocarbon compounds with a carbon-carbon double bond, along with a controlled molar fraction, and a catalyst system to form a reaction mixture that cures into a rigid polyisocyanurate foam with enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If HFCs are used as physical blowing agents, then ozone depletion is avoided, but thermal conductivity increases and greenhouse gas effect worsens
Solution Approach 1:
The patent changes the chemical composition parameters of the blowing agent system by incorporating halogenated olefins (HFOs) with specific molecular structures containing carbon-carbon double bonds, which provide lower thermal conductivity compared to conventional HFCs while maintaining acceptable GWP levels
Solution Approach 2:
The patent uses a composite blowing agent system combining multiple components including halogenated olefins, hydrocarbons, and HFCs in specific ratios, creating a synergistic mixture that achieves optimal balance between thermal conductivity, environmental impact, and foam properties
2Loss of energy
If hydrocarbons are used as physical blowing agents, then environmental impact is reduced, but thermal conductivity increases
Solution Approach 1:
The patent modifies the blowing agent composition by introducing halogenated olefins with specific molecular weights and structures (containing C=C bonds) that provide better thermal insulation properties compared to pure hydrocarbons, while maintaining low environmental impact
3Ease of manufacture
If existing blowing agents are used, then production cost is reduced, but storage stability deteriorates
Solution Approach 1:
The patent changes the chemical reactivity parameters by selecting halogenated olefins with specific functional group configurations that exhibit improved storage stability and reduced unwanted side reactions during foam production and storage
4Device complexity
If conventional blowing agents are used, then process simplicity is maintained, but foam quality deteriorates
Solution Approach 1:
The patent optimizes the blowing agent mixture ratios and molecular characteristics to achieve uniform cell structure and consistent foam density, improving manufacturing precision without requiring complex process 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 process results in polyisocyanurate foams with compressive strength greater than 80 kPa, low thermal conductivity, and excellent surface quality, while reducing the need for high amounts of flame retardants and minimizing environmental impact.
Implementation Method 1
aromatic polyisocyanate, isocyanate-reactive compounds containing at least one polyetherol (b1) and/or polyesterol (b2)... mixed to form a reaction mixture and allowed to cure to form the rigid polyisocyanurate foam
Implementation Method 2
blowing agent (d) being at least one aliphatic, halogenated hydrocarbon compound (d1)... and a hydrocarbon compound with 4 to 8 carbon atoms (d2)... to form the rigid polyisocyanurate foam
Implementation Method 3
aromatic polyisocyanate, isocyanate-reactive compounds... (c) catalyst... mixed to form a reaction mixture and allowed to cure
Data Source
AI summary
Disclosed herein is a process for producing rigid polyisocyanurate foams, where (a) aromatic polyisocyanate, (b) isocyanate-reactive compounds including at least one polyetherol (b1) and/or polyesterol (b2), wherein where the number-average content of isocyanate-reactive hydrogen atoms of components (b 1) and (b2) is at least 1.7, (c) catalyst, (d) blowing agents, (e) flame retardants, (f) optionally auxiliary and additive substances and (g) optionally compounds having aliphatic hydrophobic groups and not falling under the definition of compounds (a) to (f) are mixed to afford a reaction mixture and allowed to cure to afford a rigid polyisocyanurate foam. Further disclosed herein is a rigid polyisocyanurate foam obtainable by the process.