Photocurable Resin Composition Shrinkage Control
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Solution Overview
Problem
Photocurable resin compositions for plastics often suffer from low adhesion to substrates and appearance defects like cracking due to abrupt volume shrinkage during curing.
Innovation Solution
A photocurable resin composition combining an N-vinyl amide compound, a polyfunctional (meth)acrylate monomer, a photopolymerization initiator, and a radical scavenger, which suppresses volume shrinkage and enhances adhesion by forming a strong mechanical coupling with the plastic substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polyfunctional (meth)acrylate monomer is used to form a cured film, then surface hardness and abrasion resistance are improved, but adhesion to plastic substrate deteriorates and appearance defects such as cracks occur
Solution Approach 1:
The patent changes the chemical composition parameters of the curable resin by incorporating specific N-vinyl amide compounds (with particular R1, R2, R3, R4 group configurations) and controlling the ratio of polyfunctional (meth)acrylate monomers. This compositional parameter adjustment reduces the polymerization shrinkage rate while maintaining crosslinking density, thereby resolving the contradiction between surface hardness and adhesion
Solution Approach 2:
The patent creates a composite curable resin system combining N-vinyl amide compounds with polyfunctional (meth)acrylate monomers. This composite material approach allows the N-vinyl amide component to act as a shrinkage buffer while the (meth)acrylate component provides crosslinking for hardness, simultaneously achieving both adhesion and surface properties
2Strength
If a polyfunctional (meth)acrylate monomer is used to form a cured film, then abrasion resistance is improved, but appearance quality deteriorates due to cracks
Solution Approach 1:
By adjusting the chemical composition parameters—specifically incorporating N-vinyl amide compounds with controlled R1, R2, R3, R4 configurations and optimizing the ratio of polyfunctional (meth)acrylate monomers—the patent reduces polymerization shrinkage rate. This parameter change prevents crack formation during curing while preserving the abrasion resistance provided by the crosslinked structure
Solution Approach 2:
The N-vinyl amide compound acts as a preliminary countermeasure against shrinkage-induced cracking. By incorporating this component before curing, the system pre-compensates for the volume reduction that would otherwise cause appearance defects, allowing the polyfunctional (meth)acrylate to form its protective hard coating without causing cracks
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 high adhesion to plastic substrates without cracks, making it suitable for various applications, including optical substrates like spectacle lenses, and maintains performance over time.
Implementation Method 1
a photocurable resin composition comprising: (A) an N-vinyl amide compound represented by the following formula (1)... (B) a polyfunctional (meth)acrylate monomer... (C) a photopolymerization initiator
Implementation Method 2
a photocurable resin composition comprising: (A) an N-vinyl amide compound... (B) a polyfunctional (meth)acrylate monomer... (D) a radical scavenger... suppresses volume shrinkage and enhances adhesion
Implementation Method 3
high adhesion to a plastic substrate... forming a strong mechanical coupling with the plastic substrate
Data Source
AI summary
To provide a photocurable resin composition comprising an N-vinyl amide compound, a polyfunctional (meth)acrylate monomer and a photopolymerization initiator and having excellent adhesion to an optical substrate and free from an appearance defect such as a crack or shrinkage and a laminate having a coat layer obtained by curing the photocurable resin composition.