Water-borne UV Coating for Wood Edge Protection
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Solution Overview
Problem
Conventional aqueous UV coating compositions for wood finishing often require multiple layers and processes due to limitations in film thickness, leading to inadequate curing and micro-foam formation, which is time-consuming and costly, and may damage edges and corners if the coating is not thick enough.
Innovation Solution
A water-borne UV-curable coating composition comprising 30-70 wt% polyurethane dispersion, 10-40 wt% acrylate emulsion, 0.5-5.0 wt% silicone-free defoamer mixture, 1.2-5.0 wt% photoinitiator mixture, and optional colorants, allowing for a single high-thickness application without micro-foam formation and improved curing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thick coating layer is applied in one step to protect edges and corners, then edge and corner protection is improved, but micro-foam formation occurs at the paint surface
Solution Approach 1:
The patent modifies the chemical composition parameters of the coating system by selecting specific photoinitiators (Type I and Type II combinations) and controlling their ratios, along with adjusting monomer functionality and crosslinking density. These parameter changes enable the system to cure thick coatings (180-250 g/m²) without micro-foam formation, resolving the contradiction between achieving sufficient edge protection and preventing surface defects
Solution Approach 2:
The patent employs a composite coating formulation combining waterborne UV-curable polyurethane dispersion (30-70 wt%), acrylate emulsion (10-40 wt%), and a balanced photoinitiator system. This composite material approach creates a synergistic effect where the combination of polymers and carefully balanced photoinitiators enables thick film application without micro-foam, while the crosslinking system provides adequate curing throughout the film thickness
2Strength
If multiple lacquer layers are applied to ensure sufficient paint material, then edge and corner protection is improved, but the number of process steps increases
Solution Approach 1:
The patent merges multiple functions into a single coating layer by designing a formulation that simultaneously provides sufficient film thickness (180-250 g/m²), complete curing throughout the film, and protection against micro-foam formation. This is achieved through the balanced photoinitiator system and crosslinking mechanism, allowing one coating step and one sanding operation to replace the conventional multiple layers process, thereby improving productivity while maintaining edge and corner protection
Solution Approach 2:
By changing the photoinitiator system parameters (using both Type I and Type II photoinitiators in specific ratios) and controlling the crosslinking density through monomer selection, the patent enables a single coating layer to achieve the protective function that previously required multiple layers, thus reducing the number of process steps while maintaining adequate edge and corner protection
3Strength
If a thick coating layer is applied to avoid damage during polishing, then surface protection is improved, but adequate curing becomes difficult to achieve
Solution Approach 1:
The patent uses a composite photoinitiator system combining Type I (e.g., benzophenone, thioxanthone) and Type II (e.g., camphorquinone, hydroxyacetophenone) photoinitiators in balanced ratios. This composite approach ensures adequate curing throughout thick film layers (180-250 g/m²) by creating a synergistic effect where Type I photoinitiators initiate polymerization and Type II photoinitiators provide chain transfer and crosslinking, achieving complete curing even at high film thicknesses while maintaining surface protection
Solution Approach 2:
The patent optimizes the photoinitiator concentration (1.2-5.0 wt% of total composition) and the ratio between Type I and Type II photoinitiators, along with controlling monomer functionality and crosslinking agent content. These parameter adjustments ensure that UV energy penetrates through thick film layers effectively and initiates complete curing throughout the entire coating thickness, resolving the contradiction between achieving thick film protection and ensuring adequate curing
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
Enables a single coating step with high film thickness (180-250 g/m²) while reducing micro-foam formation and ensuring adequate curing, thus saving time and costs, and providing a durable, glossy finish with improved edge and corner protection.
Implementation Method 1
water-borne UV-curable coating composition
Implementation Method 2
mixture of photoinitiators comprising (1) 25 to 75 wt% a first photoinitiator selected from the group of acyl-phosphine-oxides, and (2) 75 to 25 wt% a second photoinitiator selected from the group of alpha-hydroxy-ketones
Implementation Method 3
mixture of defoamers comprising (i) 30 to 70 wt% of a silicone-free polymeric defoamer, and (ii) 70 to 30 wt% of a polysiloxane emulsion
Data Source
AI summary
The present invention relates to a water-borne UV-curable coating composition for use in wood finishing of interior joinery, furniture, and in particular in kitchen industry.