One Component UV Curable Coatings for Drag Reduction
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Solution Overview
Problem
Current one-component UV curable polyurethane coatings for drag-reducing applications face challenges such as high viscosity, oxygen inhibition during curing, and the need for solvents that result in VOC emissions, brittleness, and fouling issues due to surface energy limitations, which affect their performance and longevity on aircraft surfaces.
Innovation Solution
A composition comprising an unsaturated (meth)acrylate polymer, allophanate unsaturated urethane (meth)acrylate, lactone-containing (meth)acrylate, reactive diluents, an adhesion promoter, a light stabilizer, and a photoinitiator, optimized to achieve low viscosity, self-cleaning, and chemical binding of superhydrophobic acrylate chemistry within the polymer matrix, reducing fouling and enhancing weathering performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If current UV curable polyurethane compositions are used, then drag-reducing coating function is achieved, but viscosity is extremely high (10,000-200,000 cps) making handling and processing difficult
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating specific low-viscosity oligomers (epoxy resin with epoxide equivalent weight of 1,800-2,200 g/eq), reactive diluents, and catalyst systems that enable the composition to achieve usable viscosity ranges while maintaining drag-reducing functionality after curing
2Ease of manufacture
If UV curing is performed without oxygen inhibition mitigation, then curing process is simple, but uncured material remains on the outer surface
Solution Approach 1:
The patent modifies the photoinitiator system parameters by using a combination of photoinitiators with different absorption characteristics and UV wavelength requirements, enabling effective curing at lower UV energy levels (0.05 Watts/cm²) that reduces oxygen inhibition effects while maintaining process simplicity
Solution Approach 2:
The patent creates a composite curing system combining multiple photoinitiators (including Type I and Type II photoinitiators) with specific UV absorbers and stabilizers, forming a synergistic system that overcomes oxygen inhibition without requiring complex inert atmosphere equipment
3Ease of operation
If low molecular weight acrylate monomers and solvents are added to reduce viscosity, then spray application becomes possible, but VOC emissions occur
Solution Approach 1:
The patent changes the viscosity-reduction approach by using reactive diluents (acrylate-functional compounds that participate in polymerization) instead of traditional volatile solvents, achieving sprayable viscosity levels without VOC emissions since the diluents become part of the cured polymer network
Solution Approach 2:
The patent replaces permanent harmful VOC solvents with temporary reactive diluents that serve their viscosity-reduction function during application then permanently bond into the cured coating, eliminating ongoing VOC emissions while maintaining application performance
4Use of energy by moving object
If UV-A light sources with low intensity (0.05 Watts/cm²) are used, then energy consumption is reduced, but curing effectiveness is compromised
Solution Approach 1:
The patent optimizes photoinitiator concentration parameters (0.5-15 wt%) and selects photoinitiators with high quantum efficiency and broad UV absorption spectra, enabling effective polymerization at low UV energy fluxes by maximizing the utilization of incident photons
Solution Approach 2:
The patent develops a composite photoinitiator system combining multiple photoinitiators with complementary UV absorption characteristics, creating a synergistic effect that extends the effective curing wavelength range and maintains high curing efficiency at low UV energy levels (0.05 Watts/cm²)
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 enables the development of UV curable coatings with improved handling, reduced VOC emissions, enhanced flexibility, and self-cleaning properties, effectively addressing the challenges of high viscosity, oxygen inhibition, and fouling, while maintaining performance at low UV cure energy levels.
Implementation Method 1
A composition and method for making a one component UV curable coating are provided. The method comprises: applying the composition to a substrate; and irradiating the composition with ultraviolet (UV) radiation to cure the composition.
Implementation Method 2
irradiating the composition with ultraviolet (UV) radiation to cure the composition
Data Source
AI summary
A composition is provided and includes an unsaturated (meth)acrylate polymer or oligomer, an allophanate unsaturated urethane (meth)acrylate, a lactone-containing (meth)acrylate, a first reactive diluent, an adhesion promoter, a second reactive diluent, a light stabilizer, and a photoinitiator.