Dual Curing Acrylate Composition for Shadow Area Resolution
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Solution Overview
Problem
Conventional photocurable compositions based on acrylate functional compounds face challenges in achieving complete curing in areas not illuminated by actinic radiation, particularly on complex surfaces like circuit boards, leading to uncured 'shadow' regions.
Innovation Solution
A dual curing composition comprising epoxy acrylate and thiol-functional compounds, curable at room temperature, by heat, or photo-irradiation, with a molar ratio of thiol groups to acrylate groups ranging from 0.2:1 to 1:1, eliminating the need for free-radical photoinitiators and thermal initiators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If photocurable compositions are used for fast curing, then productivity is improved, but manufacturing precision deteriorates due to uncured shadow areas
Solution Approach 1:
The patent merges photocuring and thermal curing mechanisms into a single dual-curing composition. The composition contains both photoinitiator and thermal initiator, allowing it to be cured by either UV/visible light or heat treatment, thereby ensuring complete curing throughout the coating including shadow areas while maintaining fast curing capability
Solution Approach 2:
The invention uses a composite curing system combining two different curing mechanisms (photopolymerization and thermal polymerization) in one composition. This composite approach allows the material to exhibit both fast initial curing under light and complete throughout-curing when heated, resolving the contradiction between speed and completeness
2Ease of operation
If photoinitiators are used to enable photocuring, then ease of operation is improved, but harmful factors increase due to residue compounds
Solution Approach 1:
The patent changes the chemical parameters of the curing system by selecting photoinitiators and thermal initiators that decompose into harmless byproducts. Specifically, it uses compounds that produce carbon dioxide and water as residues, transforming the harmful effect into a benign outcome while maintaining the ease of dual-curing operation
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 effectively cures throughout, including shadow areas, without residual initiators, ensuring complete curing at room temperature or under heat and photo-irradiation, making it suitable for coatings, adhesives, and composite materials.
Implementation Method 1
a composition which may be cured either at room temperature or by using actinic radiation and/or heat
Implementation Method 2
cured either at room temperature or by using actinic radiation and/or heat
Data Source
AI summary
The present application is directed to a dual curing composition which may be cured at room temperature but which is also heat- and photo-curable, said composition comprising, based on the weight of the composition: from 10 to 95 wt. % of a) at least one epoxy acrylate compound having at least two acrylate groups; and, from 5 to 90 wt. % of b) at least one polythiol compound, wherein the composition is characterized in that the molar ratio of thiol groups (—SH) to acrylate groups (H2C═CHC(O)O—) is in the range from 0.2:1 to 1:1, preferably from 0.5:1 to 1:1. The composition may be further characterized as being free from free-radical initiators.