Polyesterol Composition for Rigid Polyurethane Foam Fire Safety
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Solution Overview
Problem
The production of rigid polyurethane foams faces challenges such as high viscosity issues with aromatic polyester polyols, leading to mixing difficulties with isocyanates, insufficient dimensional stability, surface defects, brittleness, and excessive smoke gas formation during fires, which affect the quality and safety of sandwich elements.
Innovation Solution
A process using a specific polyesterol composition, comprising terephthalic acid, fatty acid triglycerides, diols, and polyether polyols with high functionality, which reduces smoke gas formation and improves mechanical properties and fire behavior, while also enhancing processing ease and surface quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aromatic polyester polyols are used to produce rigid polyurethane foams, then fire behavior is improved, but viscosity increases and mixing with isocyanate becomes difficult
Solution Approach 1:
The patent modifies the chemical composition parameters of polyester polyols by incorporating specific diols (ethylene glycol, diethylene glycol, polyethylene glycol) and controlling molecular weight and functionality to reduce viscosity while maintaining fire resistance. This allows aromatic polyester polyols to be used without the severe viscosity increase that would prevent proper mixing with isocyanate.
Solution Approach 2:
The invention creates a composite polyol system combining aromatic polyester polyols with aliphatic polyester polyols and polyether polyols. This composite approach maintains the fire resistance benefits of aromatic components while the aliphatic and polyether components contribute to lower viscosity and improved processability.
2Strength
If polyester polyols with high functionality are used, then crosslinking and mechanical properties are improved, but viscosity increases and processing becomes more difficult
Solution Approach 1:
The patent carefully controls the functionality parameter of polyester polyols, using a mixture of diols with different functionalities (ethylene glycol with functionality 2, diethylene glycol with functionality 2, and polyethylene glycol with varying functionalities). This allows achieving sufficient crosslinking density for good mechanical properties while keeping the average functionality low enough to maintain acceptable viscosity for processing.
3Quantity of substance
If conventional polyester polyols are used, then production cost is reduced, but smoke gas formation during fire increases
Solution Approach 1:
The patent changes the chemical structure parameters of the polyester polyol by incorporating specific diol components (particularly polyethylene glycol) and controlling the ratio of aromatic to aliphatic components. This modification reduces the formation of toxic smoke gases during fire while maintaining cost-effectiveness through the use of commercially available starting materials and standard polycondensation processes.
4Strength
If rigid polyurethane foams are produced with high density, then mechanical strength is improved, but brittleness increases and surface defects occur
Solution Approach 1:
The invention uses a composite polyol system combining aromatic polyester polyols, aliphatic polyester polyols, and polyether polyols in specific ratios. This composite approach creates a foam structure that achieves high density and mechanical strength while the aliphatic and polyether components provide flexibility that reduces brittleness and prevents surface defects during processing.
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 rigid polyurethane foams with reduced smoke gas formation, improved mechanical properties, and enhanced processing characteristics, leading to better fire behavior and surface quality in sandwich elements.
Implementation Method 1
polyester polyols from the polycondensation of alcohols with dicarboxylic acids
Implementation Method 2
reacting organic or modified organic di- or polyisocyanates with higher molecular weight compounds with at least two reactive hydrogen atoms
Data Source
AI summary
The invention relates to polyesterols obtainable by reaction of b1) from 10 to 70 mol% of at least one compound selected from the group consisting of terephthalic acid, dimethyl terephthalate, polyethylene terephthalate, phthalic anhydride, phthalic acid and isophthalic acid, b2) from 0.8 to 4.5 mol% of a fatty acid triglyceride, b3) from 10 to 70 mol% of a diol selected from the group consisting of ethylene glycol, diethylene glycol and polyethylene glycols, b4) from 5 to 50 mol% of a polyether polyol having a functionality of greater than 2, wherein at least 200 mmol of component b4) are used per kg of the polyesterol, where the sum of the components b1) to b4) adds up to 100 mol%.