Polyetherester Polyols for Rigid Foam Fire Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The production of rigid polyurethane foams faces challenges such as high viscosity issues with polyester polyols, leading to mixing difficulties with isocyanates, insufficient dimensional stability, surface defects, brittleness, and the formation of toxic compounds during fires, along with inefficiencies in catalyst use and processing steps like neutralization and filtration.
Innovation Solution
A process using polyetherester polyols, obtained by esterification of dicarboxylic acids with aliphatic or cycloaliphatic diols and polyether polyols, in the presence of an amine catalyst, which allows for acid-catalyzed esterification without additional work-up steps, improving mixing with isocyanates and reducing processing efforts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If polyester polyols based on aromatic carboxylic acids are used, then fire behavior is improved, but viscosity increases making mixing with isocyanate difficult
Solution Approach 1:
The patent changes the chemical structure parameters of the polyol by using polyetherester polyols with specific molecular weight ranges (300-3000 g/mol) and controlled aromatic content (10-70 mol% of dicarboxylic acid component), thereby achieving lower viscosity while maintaining fire resistance
Solution Approach 2:
The patent employs composite polyetherester polyols combining aliphatic and aromatic dicarboxylic acid components, creating a material that balances the fire resistance benefits of aromatic structures with the lower viscosity characteristics of aliphatic structures
2Productivity
If KOH catalyst is used for alkoxylation, then product yield is improved, but additional workup steps are required for catalyst separation
Solution Approach 1:
The patent removes the need for catalyst separation by selecting catalysts (metal salts, carboxylic acids, sulfonic acids) that do not require neutralization and filtration steps, effectively extracting the problematic workup operations from the process
Solution Approach 2:
The chosen catalysts enable the reaction mixture to proceed directly to esterification without requiring separate neutralization and filtration steps, making the process self-sufficient and eliminating additional processing equipment
3Object-affected harmful factors
If trimethylolpropane is used as higher-functional alcoholic polyester component, then fire resistance is improved, but toxic compounds form during fire
Solution Approach 1:
The patent applies local quality by selecting specific polyetherester polyols with controlled aromatic dicarboxylic acid content (10-70 mol%) and molecular weight, creating regions of optimized fire resistance without the toxic byproducts associated with traditional polyols like trimethylolpropane
4Stability of the object's composition
If glycerin is used as higher-functional alcoholic polyester component, then dimensional stability is improved, but foam deformation occurs after demoulding
Solution Approach 1:
The patent changes the parameters of the polyol structure by using polyetherester polyols with specific molecular weights (300-3000 g/mol) and controlled functionality, achieving dimensional stability without the deformation issues observed with glycerin-based systems
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
This approach enhances the production of rigid polyurethane foams by improving dimensional stability, reducing surface defects, and providing better fire protection while minimizing catalyst usage and processing complexity.
Implementation Method 1
esterification of dicarboxylic acids with aliphatic or cycloaliphatic diols and polyether polyols, in the presence of an amine catalyst
Data Source
AI summary
The invention relates to a method for producing polyurethane rigid foams or polyisocyanurate rigid foams by reacting at least one polyisocyanate A), polyether ester polyols b) based on aromatic dicarboxylic acids which can be obtained by esterification of b1) 10 to 70 mol-% of a dicarboxylic acid composition, comprising b11) 50 to 100 mol %, based on the dicarboxylic acid composition, of one or more aromatic dicarboxylic acids or derivatives thereof, b12) 0 to 50 mol %, based on the dicarboxylic acid composition b1), of one or more aliphatic dicarboxylic acids or derivatives thereof, b2) 2 to 30 mol-% of one or more fatty acids and/or fatty acid derivatives, b3) 10 to 70 mol-% of one or more aliphatic or cycloaliphatic diols with 2 to 18 C-atoms or alkoxylates thereof, b4) 2 to 50 mol % of a polyether polyol having a functionality greater than or equal to 2, produced by alkoxylation of a polyol having a functionality greater than or equal to 2 in the presence of an amine as a catalyst, optionally additional polyester polyols C), which are different from that of components B), and at least one polyether polyol D), wherein the mass ratio of the sum of the components B) and optionally C) to component D) is at least 7. The invention also relates to the resulting hard foams and to the use thereof for the production of sandwich elements with rigid or flexible cover layers. The invention further relates to the underlying polyol components.