Optically Clear Resin Composition for Stable Inkjet Curing
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Solution Overview
Problem
Existing optically clear resins (OCRs) used in display devices face challenges in maintaining adhesive properties and stability during photocuring, especially when low viscosity is required for inkjet processes, particularly in oxygen-rich environments.
Innovation Solution
A resin composition comprising urethane (meth)acrylate oligomers, mono-functional acrylate monomers, and a hydrogen abstraction-type photoinitiator, with specific molecular weights and viscosities, allowing stable inkjet processing at room temperature and high adhesion in oxygen atmospheres.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If low viscosity optically clear resins are used for inkjet process, then inkjet processability is improved, but adhesive properties after photocuring deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the resin by incorporating specific functional monomers (epoxy acrylate, carboxylic acid group-containing monomer) and controlling the ratio of oligomer to monomer. This allows the resin to maintain low viscosity for inkjet processability while the reactive functional groups ensure high adhesive strength after photocuring. The parameter optimization balances flow characteristics with curing performance.
Solution Approach 2:
The patent creates a composite resin system combining urethane acrylate oligomer with multiple functional monomers (epoxy acrylate, carboxylic acid monomer, and other acrylate monomers). This composite formulation synergistically combines the low viscosity and adhesion promotion of functional monomers with the structural integrity and UV reactivity of the oligomer, achieving both inkjet processability and high adhesive properties after curing.
2Productivity
If photocuring is performed in oxygen atmosphere, then curing speed is improved, but adhesion strength deteriorates due to oxygen inhibition
Solution Approach 1:
The patent converts the harmful effect of oxygen (which causes inhibition and reduces adhesion) into a beneficial outcome by incorporating oxygen-resistant functional monomers. The epoxy acrylate and carboxylic acid group-containing monomers maintain high reactivity and adhesion even in the presence of oxygen, allowing the curing process to proceed effectively in atmospheric conditions without sacrificing bond strength.
Solution Approach 2:
The patent modifies the chemical composition by adding specific functional monomers that change the polymerization kinetics and oxygen resistance parameters. These monomers enable the system to cure effectively in oxygen-rich environments while maintaining high adhesion, transforming the oxygen atmosphere from a detrimental condition into an acceptable processing environment.
3Use of energy by stationary object
If room temperature inkjet process is used, then energy consumption is reduced, but viscosity control becomes more difficult
Solution Approach 1:
The patent optimizes the viscosity parameters of the resin composition by carefully selecting and ratioing components with different molecular weights and viscosities. The combination of oligomer and low-viscosity monomers creates a formulation that maintains appropriate flow characteristics at room temperature, eliminating the need for heating while ensuring proper inkjet dispensing and film formation.
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 resin composition enables stable photocuring with high adhesion and cohesive forces, maintaining physical properties and resisting yellowing under UV exposure, suitable for various display device shapes.
Implementation Method 1
a hydrogen abstraction-type photoinitiator (D)
Implementation Method 2
about 1 part by weight to about 5 parts by weight of a hydrogen abstraction-type photoinitiator (D)
Implementation Method 3
it has high adhesive strength even when photocured in an oxygen atmosphere
Data Source
AI summary
A resin composition includes about 1 part by weight to about 10 parts by weight of a urethane (meth)acrylate oligomer having two (meth)acrylic groups, about 80 parts by weight to about 95 parts by weight of a mono-functional acrylate monomer, about 0.1 parts by weight to about 1 part by weight of a (meth)acrylate monomer having two (meth)acrylic groups, and about 1 part by weight to about 5 parts by weight of a hydrogen abstraction-type photoinitiator. Some of the mono-functional acrylate monomer include a cyclopentenyl group. The resin composition may have a viscosity of greater than or equal to about 5 mPas and less than 20 mPas at 30° C.