Active Energy Ray-Curable Coating Varnish for Low Migration
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Solution Overview
Problem
Active energy ray-curable coating varnishes face challenges in suppressing the outward migration of (meth)acrylate monomers and photopolymerization initiators, which are critical components, especially in foodstuff and pharmaceutical packaging, where safety regulations like Swiss Ordinance (RS817.023.21) demand low migration levels, and simultaneously achieving excellent curability and antistatic properties.
Innovation Solution
The development of an active energy ray-curable coating varnish with specific (meth)acrylate compounds and photopolymerization initiators, including ethylene oxide-modified (meth)acrylates and α-hydroxyalkylphenone compounds, that have weight-average molecular weights within defined ranges and specific ratios, ensuring low migration, excellent curability, and antistatic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional active energy ray-curable coating varnishes are used, then excellent curability is achieved, but outward migration of (meth)acrylate monomer and photopolymerization initiator occurs
Solution Approach 1:
The patent changes the molecular weight parameter of the (meth)acrylate monomer to within a specific range (500-2000), which suppresses outward migration while maintaining curability. This parameter optimization resolves the contradiction between achieving excellent curability and preventing harmful migration of coating components.
Solution Approach 2:
The patent uses a composite formulation combining specific (meth)acrylate monomers with weight-average molecular weights of 500-2000 and photopolymerization initiators with weight-average molecular weights of 300-2000. This composite material approach achieves both excellent curability through the photopolymerization reaction and suppressed migration due to the optimized molecular weight characteristics of the components.
2Object-affected harmful factors
If molecular weight of (meth)acrylate monomer is increased to suppress migration, then outward migration is reduced, but curability deteriorates
Solution Approach 1:
The patent optimizes the molecular weight parameter of the (meth)acrylate monomer within the specific range of 500-2000. This parameter change achieves the dual benefit of suppressing outward migration (improving safety for foodstuff packaging) while maintaining excellent curability through appropriate photopolymerization reactivity.
3Manufacturing precision
If coating varnish is applied for foodstuff packaging, then print quality and protection are improved, but safety concerns arise due to potential migration into food contents
Solution Approach 1:
The patent changes the molecular weight parameter of the coating varnish components to specific ranges, which suppresses migration into food contents while maintaining the coating's protective and aesthetic functions for foodstuff packaging.
Solution Approach 2:
The patent employs a composite material system with optimized molecular weight characteristics that provides both the print quality enhancement and protection needed for packaging applications, while ensuring safety by minimizing migration into food contents through the specific molecular weight selection.
4Reliability
If photopolymerization initiator amount is increased to improve curability, then curability is enhanced, but migration increases
Solution Approach 1:
The patent optimizes the molecular weight parameter of the photopolymerization initiator to within the range of 300-2000. This parameter change enables excellent curability to be achieved while simultaneously suppressing the migration of the photopolymerization initiator, resolving the contradiction between curability enhancement and migration reduction.
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 solution effectively suppresses the outward migration of (meth)acrylate compounds and photopolymerization initiators, meeting stringent safety standards, while providing excellent curability and antistatic properties, enhancing the production efficiency and safety of printed matter for foodstuff and pharmaceutical packaging.
Implementation Method 1
An active energy ray-curable coating varnish contains an unsaturated compound such as an acrylate ester compound that exhibits curability upon irradiation with active energy rays as a structural component. This type of coating varnish cures instantaneously upon irradiation with active energy rays, with a three dimensional crosslinking reaction of the above unsaturated compound forming a tough coating film.
Data Source
AI summary
The invention provides an active energy ray-curable coating varnish which is capable of suppressing outward migration from printed matter, and which is capable of simultaneously achieving excellent curability and excellent line applicability, in addition to low yellowing characteristics. The coating varnish contains a (meth)acrylate compound (A) and a photopolymerization initiator (B), wherein at least one compound selected from the group consisting of ethylene oxide-modified pentaerythritol tetraacrylates, ethylene oxide-modified diglycerol tetraacrylates, ethylene oxide-modified trimethylolpropane triacrylates and ethylene oxide-modified ditrimethylolpropane tetraacrylates is used as the (meth)acrylate compound (A), and at least one of 2-hydroxy-1-[4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl]-2-methylpropan-1-one (b1) and oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone] (b2) is used as the photopolymerization initiator (B).