Water-Based UV Coating Wear Resistance and Crack Control
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Solution Overview
Problem
Water-based UV-curable coatings for automotive interior parts face challenges in achieving high wear resistance while avoiding film cracking and ensuring effective UV curing, particularly due to issues with film thickness and complex substrate geometries, as well as color defects in dark-colored parts.
Innovation Solution
A water-based UV coating formulation comprising water-based polycarbonate dispersion, aliphatic polyurethane acrylate dispersion, UV reactive diluents, photoinitiators, auxiliary agents, and a combination of UV and thermal curing, which balances wear resistance and crack resistance by controlling the molecular weight and functionality of the dispersions, and using nano black pigment dispersion to address color issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the coating film thickness is increased to ensure high wear resistance, then wear resistance is improved, but the coating film is more prone to cracking and UV curing effectiveness is compromised
Solution Approach 1:
The patent modifies the chemical composition parameters of the coating system by incorporating specific water-based polymers with controlled molecular weights and functionalities, along with dual-curing agents, to achieve a coating formulation that provides high wear resistance without increasing film thickness, thereby avoiding cracking issues
Solution Approach 2:
The patent creates a composite coating system combining water-based polymers, UV-curable components, and thermal-curing agents, forming a multi-functional coating composition that simultaneously achieves wear resistance, crack resistance, and effective curing without requiring increased film thickness
2Strength
If the coating film thickness is increased to meet wear resistance standards, then wear resistance is improved, but UV curing effectiveness is reduced
Solution Approach 1:
The patent changes the curing mechanism parameters by introducing dual-curing technology that combines UV photopolymerization with thermal curing, allowing effective curing at lower film thicknesses while maintaining wear resistance through optimized polymer composition and crosslinking density
3Manufacturing precision
If water-based nano black pigment dispersion is added to cover color defects, then color coverage is improved, but volume shrinkage difference between layers causes poor film-build and uneven color
Solution Approach 1:
The patent adjusts the pigment dispersion parameters by using specifically formulated water-based nano black pigment with optimized particle size distribution and surface treatment, combined with modified polymer matrices, to reduce volume shrinkage during curing and achieve uniform film-build while maintaining excellent color coverage
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 coating achieves a balance between excellent wear resistance and crack resistance, ensures effective curing on complex geometries, and prevents volume shrinkage-related color unevenness, meeting stringent industry standards like VW TL226 for wear resistance and gloss retention.
Implementation Method 1
Ultraviolet (UV) curable coatings are a type of coatings that utilize UV initiators to trigger free-radical polymerization of liquid oligomers and monomers in the coating system, achieving crosslinking and curing to form a film
Data Source
AI summary
A water-based dual-cure coating comprising the following raw material components: 15-25 parts by weight of a water-based polycarbonate dispersion, 30-60 parts by weight of a water-based aliphatic polyurethane acrylate dispersion, 5-15 parts by weight of a UV reactive diluent, 1-4 parts by weight of a photoinitiator, 0.2-1 part by weight of an auxiliary agent, 3-8 parts by weight of a film coalescing aid, and 5-15 parts by weight of water. The coating is sprayed onto an automotive interior part and subsequently cured by baking at a temperature of 50-65° C. to form a film, proceeding UV curing; and proceeding thermal curing at temperature of 70-80° C.