Polyurethane-Isocyanurate Polymer Hardness Without Formaldehyde
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Solution Overview
Problem
Phenolic-formaldehyde resins, widely used for their hardness, face issues with residual formaldehyde outgassing and property loss under high temperature, elevated pressure, and moisture conditions, necessitating an alternative polymer that maintains its properties effectively.
Innovation Solution
A method for producing isocyanurate or polyurethane-isocyanurate polymers by curing aromatic polyisocyanates with polyols in the presence of an isocyanate trimerization catalyst, followed by exposure to high temperature water under superatmospheric pressure, resulting in polymers with a glass transition temperature of at least 100°C and enhanced resistance to water exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If phenolic-formaldehyde resins are used to achieve hardness, then hardness is improved, but residual formaldehyde outgassing occurs creating exposure issues
Solution Approach 1:
The invention changes the chemical composition parameters by using aromatic polyisocyanates with specific isocyanate functionality (1.9-4) and equivalent weight (80-160) combined with polyols having hydroxyl equivalent weight up to 200, and controlling isocyanate index at least 2.00, to produce polymers that achieve comparable hardness without formaldehyde outgassing
Solution Approach 2:
The invention creates composite polymer structures by reacting aromatic polyisocyanates with polyols in the presence of isocyanate trimerization catalysts to form polyisocyanurate or polyurethane-isocyanurate polymers, combining multiple chemical components to achieve both hardness and environmental safety
2Strength
If phenolic-formaldehyde resins are used to achieve hardness, then hardness is improved, but property loss occurs under high temperature, elevated pressure, and moisture conditions
Solution Approach 1:
The invention optimizes chemical parameters including isocyanate functionality (1.9-4), equivalent weight (80-160), polyol hydroxyl equivalent weight (up to 200), and isocyanate index (at least 2.00) to create polymers with superior thermal and moisture resistance while maintaining hardness
Solution Approach 2:
The invention develops composite polyisocyanurate-polyurethane structures that combine the benefits of both polymer types, achieving both mechanical strength and environmental stability under harsh conditions of high temperature, pressure, and moisture
3Temperature
If isocyanate index is increased to at least 2.00 and isocyanate functionality is increased to 1.9-4, then glass transition temperature increases to at least 100°C, but polymerization complexity increases
Solution Approach 1:
The invention introduces isocyanate trimerization catalysts as intermediaries to facilitate the polymerization reaction, enabling the formation of high glass transition temperature polymers through controlled chemical pathways that simplify the overall process despite the complex stoichiometry
Solution Approach 2:
The invention systematically adjusts multiple parameters including isocyanate index (at least 2.00), isocyanate functionality (1.9-4), and equivalent weights to achieve the target glass transition temperature of at least 100°C, optimizing the balance between performance and processability
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 resulting polymers exhibit increased glass transition temperature and improved resistance to high temperature water exposure, maintaining their physical properties, unlike phenolic-formaldehyde resins, which often degrade under similar conditions.
Implementation Method 1
curing an aromatic polyisocyanate or a mixture of at least one aromatic polyisocyanate and at least one polyol having a hydroxyl equivalent weight of up to 200 in which the isocyanate index is at least 2.00, by heating to a temperature of from 50°C to 180°C in the presence of at least one isocyanate trimerization catalyst
Implementation Method 2
by heating to a temperature of from 50°C to 180°C
Implementation Method 3
to form a polyisocyanurate or polyurethane-isocyanurate polymer having a glass transition temperature of at least 100°C
Data Source
AI summary
Polyisocyanurate or polyurethane-isocyanurate polymers are made by curing an aromatic polyisocyanate or a mixture of at least one aromatic polyisocyanate and at least one polyol having a hydroxyl equivalent weight of up to 200 in which the isocyanate index is at least 2.00, in the presence of at least one isocyanate trimerization catalyst, to form a polyisocyanurate or polyurethane-isocyanurate polymer having a glass transition temperature of at least 100°C, and then exposing the polyisocyanurate or polyurethane- isocyanurate polymer formed step a) to water under superatmospheric pressure at a temperature of at least 70°C.