Photo-curable Ink Composition with High-Molecular-Weight Antioxidant
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Solution Overview
Problem
Photo-curable ink compositions face issues with inconsistent curing performance over time, leading to insufficient hardness and adhesion to substrates, particularly non-absorbable materials like plastics, due to the use of low-molecular-weight antioxidants which fail to provide adequate blocking resistance.
Innovation Solution
Incorporating a polymer with a structural unit containing a thioether, phosphorus, or hindered phenol structure to prevent oxidation and enhance radical polymerization inhibition, thereby improving the curing reactivity, hardness, and adhesion of the ink to substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low-molecular-weight antioxidants are used to prevent oxidation, then oxidation resistance is improved, but hardness and blocking resistance of the cured film deteriorate
Solution Approach 1:
The patent changes the molecular weight parameter of the antioxidant from low-molecular-weight to high-molecular-weight (specifically weight-average molecular weight of 1,000 to 50,000), which fundamentally alters the properties of the antioxidant. This parameter change allows the antioxidant to provide both oxidation resistance and adequate hardness/blocking resistance in the cured film, resolving the contradiction between these two properties.
Solution Approach 2:
The patent uses a composite approach by combining the high-molecular-weight polymer antioxidant with other components (radical-polymerizable monomers, photopolymerization initiator, and optionally cationic polymer) to create a multi-functional system. The high-molecular-weight polymer serves dual purposes as both antioxidant and hardness-providing component, while other components contribute to curing and adhesion, collectively resolving the property contradictions.
2Reliability
If low-molecular-weight antioxidants are used, then oxidation prevention is improved, but adhesion to non-absorbable substrates deteriorates
Solution Approach 1:
The patent changes the molecular weight parameter of the antioxidant component to high-molecular-weight range, which fundamentally improves adhesion to non-absorbable substrates while maintaining oxidation prevention capability. The high molecular weight provides better substrate interaction and bonding, resolving the adhesion problem.
Solution Approach 2:
The patent creates a composite ink composition where the high-molecular-weight polymer antioxidant works synergistically with other components (radical-polymerizable monomers, photopolymerization initiator, cationic polymer) to achieve both oxidation prevention and improved adhesion to non-absorbable substrates through combined effects.
3Adaptability or versatility
If photo-curability is enhanced for broad applications, then application versatility is improved, but curing performance stability over time deteriorates
Solution Approach 1:
The patent employs a composite formulation containing both radical-polymerizable monomers (for photo-curability and broad application suitability) and cationic polymer (for enhanced curing performance and stability). This composite approach allows the ink to maintain versatile photo-curability while achieving stable curing performance over time through the synergistic interaction of different polymerization mechanisms.
Solution Approach 2:
The patent adjusts the compositional parameters by incorporating high-molecular-weight polymer antioxidant (weight-average molecular weight of 1,000 to 50,000) which stabilizes the curing performance over time while maintaining the photo-curable properties necessary for broad applications.
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 significantly enhances the hardness and blocking resistance of the cured film while improving adhesion to substrates, particularly non-absorbable materials, by effectively terminating oxygen radical reactions and maintaining stability during the inkjet printing process.
Implementation Method 1
a photopolymerization initiator which generates radicals through photolysis
Implementation Method 2
a radical-polymerizable monomer... to form a cured film
Implementation Method 3
a polymer including a structural unit represented by General Formula (1)... capable of terminating oxygen radical reactions
Data Source
AI summary
A photo-curable ink composition is provided, the composition including: a polymer including a structural unit represented by General Formula 1 below; and a radical-polymerizable monomer, in which a total content of a monofunctional radical-polymerizable monomer and a bifunctional radical-polymerizable monomer is 50% by mass or more with respect to a total amount of the composition: in which, in General Formula 1: R1 represents a hydrogen atom or a methyl group; X represents an oxygen atom or -NR2-, R2 representing a hydrogen atom or an alkyl group having 1 to 8 carbon atoms; Y represents a group including at least one selected from the group consisting of a thioether structure, a phosphorus atom, and a hindered phenol structure; and * represents a bonding site.