Polyisocyanurate Foam Catalyst System for Formic Acid Blowing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing polyisocyanurate rigid foams using formic acid as a blowing agent result in slow hardening, leading to long molding times and low economic efficiency, and surface defects that impair adhesion and aesthetics, especially in continuous processes like the double belt process.
Innovation Solution
A process involving isocyanates, compounds reactive towards isocyanates, formic acid as a blowing agent, and a catalyst system with specific trimerization catalysts, such as ammonium or alkali metal salts of carboxylic acids, to improve hardening and mechanical properties while reducing surface defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If formic acid is used as a blowing agent in polyisocyanurate rigid foam production, then the foam can be produced without halogenated propellants, but the hardening process becomes slow resulting in long molding times
Solution Approach 1:
A catalyst system comprising a metal salt of a carboxylic acid (e.g., zinc stearate, calcium stearate) and an amine catalyst (e.g., dimethylcyclohexylamine, pentamethyldiethylenetriamine) is introduced as an intermediary to accelerate the hardening reaction. The metal salt activates formic acid to generate CO2 more effectively, while the amine catalyst promotes isocyanate polymerization, together resolving the slow hardening issue while maintaining formic acid as the blowing agent
Solution Approach 2:
The catalyst system changes the reaction parameters by providing alternative catalytic pathways. The metal salt catalyst modifies the decomposition kinetics of formic acid, and the amine catalyst adjusts the polymerization rate, collectively transforming the slow hardening process into an efficient one without requiring halogenated propellants
2Object-affected harmful factors
If formic acid is used as a blowing agent, then environmental requirements are met, but surface defects occur that impair adhesion and aesthetics
Solution Approach 1:
The dual-catalyst system acts as an intermediary control mechanism that balances gas generation and polymerization rates. The metal salt catalyst controls formic acid decomposition to produce gas uniformly, while the amine catalyst ensures synchronous polymerization, preventing the surface defects and adhesion problems that would otherwise occur with formic acid blowing
Solution Approach 2:
The catalyst system modifies the reaction parameters to achieve optimal gas evolution and polymerization kinetics. By adjusting catalyst ratios and types, the process transforms formic acid from a surface-defect-causing blowing agent into an environmentally compliant agent that produces high-quality surfaces
3Reliability
If water is used as a chemical blowing agent to achieve good fire properties, then flame retardancy is improved, but excessive isocyanate is consumed reducing productivity
Solution Approach 1:
Formic acid is used as a disposable blowing agent that decomposes to release CO2 without consuming excessive isocyanate. Unlike water which requires significant isocyanate for reaction, formic acid provides the necessary gas generation while preserving isocyanate for foam structure formation, thus maintaining both fire resistance and productivity
Solution Approach 2:
The blowing agent is changed from water to formic acid, fundamentally altering the stoichiometry of the reaction. This parameter change reduces isocyanate consumption while maintaining gas generation capacity, thereby improving productivity without sacrificing the fire-resistant properties of polyisocyanurate foam
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 enhances the hardening and mechanical properties of polyisocyanurate rigid foams, reduces surface defects, and meets stringent fire test standards like SBI and LPS 1181 without using halogenated propellants, enabling more efficient continuous production.
Implementation Method 1
a catalyst system and e) possibly foam stabilizers, flame retardants and other additives, where the catalyst system i) at least one compound of the structure
Implementation Method 2
reacting a) isocyanates with b) compounds with groups reactive towards isocyanates
Implementation Method 3
isocyanurate structures or other structures that arise from the reaction of isocyanate groups with other groups, such as polyurethane groups, are formed by the reaction of the isocyanate groups with one another
Data Source
AI summary
The invention relates to a catalyst system, particularly for formic-acid-blown polyisocyanurate rigid foams, a method for the production thereof and polyisocyanurate rigid foams obtainable by such a method.