Dual Cure Coating Resin for Uniform Hardness on Complex Geometries
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Solution Overview
Problem
Dual cure compositions fail to achieve consistent hardness, solvent resistance, acid resistance, and scratch/mar resistance across all surface zones of complex three-dimensional substrates, such as automotive bodies, particularly in areas inaccessible to UV radiation.
Innovation Solution
A dual cure composition comprising partially acrylated tri or polyalcohols, crosslinking agents, photoinitiators, radical scavengers, and reactive diluents, which allows for excellent curing properties when exposed to both thermal and UV radiation, ensuring uniform performance on complex geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dual cure compositions are used with conventional polyester resins esterified with acrylic acid, then UV curing provides excellent surface properties in directly accessible areas, but thermal curing alone in shaded areas produces inadequate hardness and poor scratch resistance
Solution Approach 1:
The patent changes the chemical parameters of the resin system by using partially acrylated polyalcohols with specific hydroxyl values (50-500 mg KOH/g) and double bond concentrations (1-10 mmoles/g), along with specific crosslinking agents, to achieve uniform curing properties that maintain adequate hardness in thermally cured areas while preserving excellent surface properties in UV-cured areas
Solution Approach 2:
The patent creates a composite resin system combining partially acrylated polyalcohol components with crosslinking agents and photoinitiators, where the synergistic interaction between thermal and UV curing mechanisms produces a unified coating system that delivers consistent performance across all surface zones, eliminating the property disparity between thermally and UV-cured areas
2Reliability
If the composition uses high molecular weight polymers to improve solvent resistance, then acid resistance and hardness improve, but the composition becomes less adaptable to complex three-dimensional geometries and UV radiation penetration
Solution Approach 1:
The patent optimizes the molecular weight parameters of the polyalcohol components and controls the degree of acrylation to achieve a balance where the composition maintains sufficient viscosity for solvent resistance while remaining fluid enough to conform to complex three-dimensional automotive body geometries and allow adequate UV radiation penetration for uniform curing
Solution Approach 2:
The patent creates a resin system where the partially acrylated polyalcohol components provide localized reactivity that enables uniform curing throughout the coating thickness on complex geometries, ensuring that both directly accessible and shaded areas achieve consistent hardness, solvent resistance, and acid resistance properties
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 composition achieves excellent solvent resistance, acid resistance, and hardness when cured thermally and by UV irradiation, addressing the limitations of prior art by providing consistent performance on intricate surfaces.
Implementation Method 1
a composition being curable by free-radical polymerisation, such as by UV irradiation
Implementation Method 2
curable by thermally induced polyaddition or polycondensation with participation of hydroxyl groups
Data Source
AI summary
A liquid radiation and thermally curing composition characterized in, that said composition comprises at least one ester between at least one tri or polyalcohol and acrylic and/or methacrylic acid, which ester has at least two hydroxyl groups, at least one acrylic or methacrylic double bond, a hydroxyl value of 50-500 mg KOH/g and a double bond concentration of 1-10 mmoles/g, at least one crosslinking agent for hydroxyl functional compounds, which crosslinking agent optionally has at least one olefinic double bond, and an additive package comprising at least one photoinitiator, radical scavenger, light stabilizer, wetting agent and/or leveling agent, and optionally at least one monomeric or oligomeric reactive diluent.