Polyester-Polyurethane Hybrid Resin for Gel Coat Moisture Resistance
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Solution Overview
Problem
Current polyester-polyurethane hybrid resins used in gel coats for applications like windmill blades lack superior moisture-resistance and toughness, particularly in stressful environmental conditions, which can lead to cracking and deterioration of underlying laminates.
Innovation Solution
A hybrid resin composition comprising an A part with an aliphatic polyfunctional isocyanate compound and a free radical polymerization initiator, and a B part with an ethylenically unsaturated, substantially water-free polyester polyol and a polyurethane catalyst, with a specific molar ratio of NCO groups to OH groups, providing improved crosslinking and chain extension functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyester-polyurethane hybrid resins are used in gel coats, then the resin provides basic toughness and strength, but the moisture-resistance and resistance to cracking in stressful environmental conditions are insufficient
Solution Approach 1:
The patent uses a composite resin system combining polyester polyol, polyurethane catalyst, and aliphatic polyisocyanate to create a hybrid gel coat that achieves both superior moisture-resistance and toughness. The specific combination of components creates a crosslinked network structure that provides enhanced durability and resistance to environmental forces while maintaining mechanical strength.
Solution Approach 2:
The patent specifies precise parameter ranges including the molar ratio of NCO groups to OH groups (0.3 to 2.0, preferably 0.5 to 1.5), isocyanate content (5 to 50 percent), and acid value (10 or less) to optimize the resin's performance. These controlled parameter changes ensure the gel coat achieves both moisture-resistance and toughness requirements.
2Reliability
If conventional polyester-polyurethane hybrid resins are used in gel coats, then the resin provides basic crosslinking and chain extension functions, but the resistance to cracking and deterioration under environmental forces is insufficient
Solution Approach 1:
The patent employs a multi-component composite system (polyester polyol, polyurethane catalyst, aliphatic polyisocyanate, and optional catalyst promoter) that works synergistically to provide enhanced resistance to cracking and environmental deterioration while maintaining ease of processing through standard gel coat application methods.
Solution Approach 2:
The patent optimizes processing parameters including the molar ratio of NCO to OH groups (0.3 to 2.0), isocyanate content (5 to 50 percent), and acid value (10 or less) to ensure the resin remains workable during application while curing to provide superior crack resistance and environmental durability.
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 hybrid resin composition enhances the moisture-resistance, toughness, and thermal properties of gel coats, leading to better protection against environmental forces and improved durability, as demonstrated by enhanced water resistance and mechanical properties compared to conventional gel coats.
Implementation Method 1
A hybrid resin composition is disclosed which comprises an aliphatic polyfunctional isocyanate compound and a polyester catalyst and an ethylenically unsaturated, substantially water-free, polyester polyol and a polyurethane catalyst
Implementation Method 2
A. An A part composition comprising an aliphatic polyfunctional isocyanate compound and a free radical polymerization initiator
Data Source
AI summary
A hybrid resin composition is described, the composition comprising:A. An A part composition comprising an aliphatic polyfunctional isocyanate compound and a free radical polymerization initiator; andB. A B part composition comprising an ethylenically unsaturated, substantially water-free polyester polyol and a polyurethane catalyst.The A part composition can contain a non-interfering solvent, e.g., styrene, and the B part composition typically has an acid value of 5 or less (based on solids). For outdoor use, the B part composition is preferably free of tertiary hydrogens, ether glycols and terephthalic acid residues.