Cyclohexyl Crystalline Gellant for Self-Leveling UV Inks
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Solution Overview
Problem
Conventional methods fail to effectively level UV curable gel inks prior to curing due to their unique properties, such as low cohesive strength and strong affinity to materials, leading to issues like cohesive failure and residual ink on leveling devices.
Innovation Solution
The development of a self-leveling curable solid ink composition incorporating a cyclohexyl-based crystalline gellant with specific formulae, which exhibits crystalline behavior and tuned viscoelastic properties, allowing for non-contact leveling of the inks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional leveling methods are used with UV curable gel inks, then the ink can be applied to substrates, but the ink sticks to the leveling device and undergoes cohesive failure leaving residual ink
Solution Approach 1:
The patent changes the physical and chemical parameters of the gellant material, specifically using crystalline gellants with controlled melting points and glass transition temperatures. This parameter change allows the ink to maintain sufficient cohesive strength during application while enabling effective leveling without sticking to conventional leveling devices.
Solution Approach 2:
The patent employs composite ink formulations combining curable monomers, crystalline gellants, and other additives in specific ratios. This composite approach creates an ink system that balances cohesive strength, levelability, and curing characteristics, resolving the contradiction between manufacturing ease and reliability.
2Ease of operation
If the ink is made with low viscosity for easy jetting, then the ink can be applied smoothly, but the ink cannot maintain its gel consistency and solidify properly on the substrate
Solution Approach 1:
The patent utilizes temperature-dependent parameter changes in the crystalline gellant system. At jetting temperatures, the gellant is in a low-viscosity state enabling smooth flow, while upon cooling to substrate temperature, the gellant crystallizes and increases viscosity to maintain gel consistency and prevent de-wetting.
Solution Approach 2:
The patent exploits phase transitions of the crystalline gellant between solid and liquid states at different temperatures. The gellant transitions from a crystalline solid at room temperature to a melted state during jetting, then re-crystallizes on the substrate, enabling the ink to flow during application and solidify to maintain consistency afterward.
3Strength
If the ink is designed with strong affinity to many materials for good adhesion, then the ink bonds well to substrates, but the ink cannot be leveled uniformly and creates corduroy effects
Solution Approach 1:
The patent adjusts the chemical composition and physical parameters of the gellant to optimize the balance between adhesion and levelability. Crystalline gellants with specific melting points and glass transition temperatures provide sufficient adhesion while maintaining enough cohesion to prevent excessive spreading and corduroy effects during the leveling process.
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 cyclohexyl-based crystalline gellant enables the inks to self-level without physical contact, resulting in improved print uniformity, reduced 'corduroy' effect, and enhanced gloss, while maintaining high hardness and minimal shrinkage post-curing.
Implementation Method 1
a cyclohexyl-based crystalline gellant (or referred to as 'crystalline gellant'); wherein the cyclohexyl-based crystalline gellant has a tan δ above about 0.08, and a melting point of above about 100° C.
Implementation Method 2
which exhibits crystalline behavior and tuned viscoelastic properties, allowing for non-contact leveling of the inks
Implementation Method 3
A UV curable solid ink is characterized by being a gel-like consistency at room temperature and a low viscosity liquid at an elevated temperature for jetting on a substrate. When the ejected ink hits the substrate, it changes phase from the liquid back to its more viscous gel consistency.
Implementation Method 4
Once the gel ink is exposed to UV radiation, the ink is cured to form a cross-linked polymer matrix resulting in a very hard and durable mark on the substrate.
Data Source
AI summary
Disclosed herein are curable solid inks which are solid at room temperature and molten at an elevated temperature at which the molten ink is applied to a substrate. In particular, the curable solid ink of the present embodiments comprises a cyclohexyl-based crystalline gellant that impart self-leveling capabilities to the inks, where the cyclohexyl-based crystalline gellant have a structure of Formula I:wherein each X, Y, p, q, R1, R2, R3, and R4 are as defined herein.