Low-Monomer Isocyanate Prepolymer for Safer Coating Handling
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Solution Overview
Problem
Isocyanate-terminated prepolymers used in coating systems pose a risk of skin sensitization, necessitating expensive handling systems and protective measures due to their potential to cause allergic reactions.
Innovation Solution
Development of isocyanate-terminated prepolymers with reduced skin sensitization potential, achieved by controlling the functional group equivalent weight (FGEW) to ≥560 g/mol and residual monomeric diisocyanate content to <0.2% by weight, ensuring a lysine mean depletion in the Direct Peptide Reactivity Assay (DPRA) of ≤1.00%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If isocyanate-terminated prepolymers are used as curing components in coating systems, then the coating performance is improved, but skin sensitisation risk increases requiring expensive protective measures
Solution Approach 1:
The patent applies parameter changes by precisely controlling the functional group equivalent weight (FGEW) to ≥560 g/mol and residual monomeric diisocyanate content to <0.2% by weight. These parameter adjustments transform the chemical properties of the prepolymer to reduce skin sensitisation potential while preserving coating performance, eliminating the need for expensive protective measures
2Object-affected harmful factors
If residual monomeric diisocyanate content is reduced to <0.2% by weight, then skin sensitisation potential is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs feedback control in the manufacturing process to monitor and adjust the reaction conditions, ensuring that residual monomeric diisocyanate content remains below 0.2% by weight. This feedback mechanism allows precise control of the polymerization process while maintaining cost-effectiveness through optimized reaction parameters and controlled addition sequences
3Object-affected harmful factors
If functional group equivalent weight is increased to ≥560 g/mol, then skin sensitisation risk is reduced, but coating system reactivity may be affected
Solution Approach 1:
The patent utilizes parameter changes by setting the functional group equivalent weight (FGEW) to ≥560 g/mol, which fundamentally alters the reactivity profile of the prepolymer. This parameter optimization reduces skin sensitisation risk while maintaining adequate coating system reactivity through balanced molecular weight control and functional group distribution
Solution Approach 2:
The patent applies dynamics by creating a prepolymer system where the higher FGEW enables more controlled and progressive reaction kinetics. The dynamic balance between molecular weight and functional group concentration allows the system to maintain reactivity while reducing harmful effects, adapting the reaction rate to optimal levels
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
Enhances worker safety by reducing the need for stringent safety measures and allowing safer handling, enabling use in manual applications such as coatings, adhesives, and sealants without the risk of skin sensitization.
Implementation Method 1
the prepolymers then react in the coating or coating system with further polyols, for example with polyacrylate polyols, to give the corresponding polyurethanes
Data Source
AI summary
The present application relates to an isocyanate-terminated prepolymer obtained by reaction of(I) At least one polyol, with a stoichiometric excess of(II) At least one monomeric diisocyanate,wherein the isocyanate-terminated prepolymer hasi. a functional group equivalent weight FGEW of ≥560 g/mol,ii. a content of residual non-reacted monomeric diisocyanate of <0.2% by weight.