Radiation-Curable Ink Jet Ink Composition Balancing Viscosity and Blocking
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Solution Overview
Problem
Ink compositions with high monofunctional monomer content form soft coatings prone to blocking, while reducing monofunctional monomers increases viscosity and decreases adhesion.
Innovation Solution
A radiation-curable ink jet ink composition with a balanced ratio of monofunctional and multifunctional monomers, including specific monomers with controlled glass transition temperatures and a vinyl-containing (meth)acrylate, to enhance adhesion and reduce viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the monofunctional monomer content is increased to 85% by mass or more, then the adhesion of ink coatings is improved, but the cured ink coatings become soft and prone to blocking
Solution Approach 1:
The patent changes the glass transition temperature parameter of the homopolymer formed from monofunctional monomers to 50°C or higher, which fundamentally alters the physical properties of the cured coating. This parameter change enables the coating to maintain both high adhesion and resistance to blocking by achieving a glass transition temperature that provides sufficient hardness and structural stability while retaining bonding capability.
Solution Approach 2:
The patent creates a composite polymer system by combining monofunctional monomers (forming the adhesive matrix) with multifunctional monomers (providing crosslinking and structural reinforcement). This composite approach allows the system to simultaneously achieve high adhesion from the monofunctional component and resistance to blocking through the crosslinked network structure formed by the multifunctional component.
2Reliability
If the monofunctional monomer content is reduced, then the proportion of multifunctional monomers increases, but the ink viscosity increases and adhesion decreases
Solution Approach 1:
The patent changes the glass transition temperature parameter of the homopolymer to 50°C or higher, which allows the use of monofunctional monomers with higher Tg values. This parameter change enables the formulation to maintain low viscosity (ease of operation) while still achieving the desired adhesion and blocking resistance, as the high Tg monomers provide structural integrity without requiring high multifunctional monomer content that would increase viscosity.
3Strength
If the proportion of multifunctional monomers is increased, then the crosslinking density increases, but the ink viscosity increases and the ink coatings become less resistant to rubbing
Solution Approach 1:
The patent changes the glass transition temperature parameter to 50°C or higher, which fundamentally alters the relationship between crosslinking density and viscosity. High Tg monomers provide inherent structural rigidity and resistance to rubbing, allowing the formulation to achieve high crosslinking density without proportionally increasing viscosity, as the Tg effect dominates the flow behavior.
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 improved adhesion and resistance to rubbing while maintaining low viscosity, addressing the issues of blocking and viscosity in existing ink compositions.
Implementation Method 1
radiation-curable ink jet ink composition... irradiating the radiation-curable ink jet ink composition on the printing medium with radiation
Data Source
AI summary
A radiation-curable ink jet ink composition contains polymerizable monomers A including at least one monofunctional monomer B and at least one multifunctional monomer C. The polymerizable monomers A include at least one polymerizable monomer A1 whose homopolymer has a glass transition temperature of 50° C. or more in a proportion of 20% by mass or more relative to the total mass of the polymerizable monomers A. Homopolymers of the polymerizable monomers A have glass transition temperatures whose average weighted by the proportions by mass of the individual polymerizable monomers A is 25° C. to 40° C. The amount of at least one monofunctional monomer B is 50% to 80% by mass relative to the total mass of the polymerizable monomers A. The at least one multifunctional monomer C includes a specific vinyl group-containing (meth)acrylate C1.