Elastic Coating System with High-Functionality Polyisocyanate
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Solution Overview
Problem
Existing soft-touch coatings exhibit inadequate chemical resistance and slow curing speeds, compromising their industrial productivity and tactile properties.
Innovation Solution
A two-component system comprising a polymeric polyol with low OH content and a polyisocyanate with high isocyanate group functionality, containing isocyanurate and allophanate groups, is used to enhance chemical resistance and curing speed while maintaining elasticity and tactility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyisocyanate curing agents with low functionality are used, then the coating maintains good elasticity and tactility, but the chemical resistance and curing speed are inadequate
Solution Approach 1:
The patent changes the key parameter of polyisocyanate functionality from conventional low values (2-3) to high values (≥4.0), while carefully controlling the molecular weight distribution (≤780 g/mol) and composition (isocyanurate and allophanate groups) to achieve both improved chemical resistance and maintained curing speed
Solution Approach 2:
The patent creates a composite curing agent system combining polyisocyanate oligomers with specific functional groups (isocyanurate and allophanate) and controlled molecular weight distribution, achieving synergistic effects that simultaneously improve chemical resistance and maintain elasticity
2Reliability
If polyisocyanate with high functionality is used to improve chemical resistance, then chemical resistance improves, but the elasticity and tactility of the coating deteriorate
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: high functionality (≥4.0), low molecular weight (≤780 g/mol), and specific group composition (isocyanurate and allophanate groups) to achieve a balance where chemical resistance improves while elasticity is maintained through the low molecular weight and flexible chain structure
3Stability of the object's composition
If conventional curing agents are used to maintain elasticity, then good tactile properties are achieved, but the curing speed is slow leading to poor productivity
Solution Approach 1:
The patent changes the functionality parameter to high values (≥4.0) which accelerates curing speed and improves productivity, while compensating for potential tactility loss through optimized molecular weight (≤780 g/mol) and specific functional group composition that maintains film flexibility
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 significantly improves chemical resistance and curing speed, maintaining or improving tactile properties, thus addressing the limitations of prior art coatings.
Implementation Method 1
the polyisocyanate is obtained by oligomerization of at least one aliphatic, cycloaliphatic or araliphatic monomeric diisocyanate and at least one hydroxy-functional compound in the presence of a catalyst
Implementation Method 2
a polyisocyanate which has a number average isocyanate group functionality of ≥ 4.0 to ≤ 10.0, based on the total solids content of the polyisocyanate, a fraction of ≤ 25 wt%, preferably ≤ 19 wt%, based on the total solids content of the polyisocyanate, of oligomers containing isocyanate groups and having a number-average molecular weight of ≤ 780 g/mol, and an isocyanurate group fraction of ≥ 5 mol% to ≤ 70 mol%, based on the total amount of isocyanurate groups and allophanate groups in the polyisocyanate
Data Source
AI summary
A two-component system is provided, which comprises a component A) comprising at least one polymeric polyol which has an OH content of ≤ 4.5 wt%, based on the total solids content of the polymeric polyol, and a component B) comprising at least one polyisocyanate which has a number average isocyanate group functionality of ≥ 4.0 to ≤ 10.0, based on the total solids content of the polyisocyanate, a fraction of ≤ 25 wt%, based on the total solids content of the polyisocyanate, of oligomers containing isocyanate groups and having a number-average molecular weight of ≤ 780 g/mol, and an isocyanurate group fraction of ≥ 5 mol% to ≤ 70 mol%, based on the total amount of isocyanurate groups and allophanate groups in the polyisocyanate. A method is also provided for producing a coating on a substrate, to the coating obtainable by this method, and to the coated substrate.