Ink-Jet Ink Formulation for Adhesion and Viscosity
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Solution Overview
Problem
Ink-jet inks face challenges in incorporating passive resins to enhance adhesion and cure speed without increasing viscosity, which is necessary for radiation-cured coatings on plastics substrates, as traditional passive materials have high solution viscosity, precluding their use at effective levels.
Innovation Solution
The development of an ink-jet ink formulation that includes a high proportion of monofunctional (meth)acrylate monomers and a thermoplastic acrylic resin, such as Paraloid DM55, which balances viscosity and adhesion properties, allowing for efficient curing and adhesion without the need for volatile solvents, and includes a photoinitiator and pigment for UV curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive resin is incorporated into ink-jet ink to enhance adhesion and cure speed, then adhesion and cure speed are improved, but viscosity increases which precludes effective use in ink-jet printing
Solution Approach 1:
The patent changes the molecular weight parameter of the passive resin to a specific range (1,500-70,000) and controls its concentration (2-15 wt%), which fundamentally alters the viscosity-adhesion relationship. This parameter optimization allows the resin to provide adhesion benefits without excessively increasing viscosity, resolving the contradiction between reliability and compositional stability.
Solution Approach 2:
The patent creates a composite ink formulation combining monofunctional (meth)acrylate monomers with thermoplastic acrylic resin and photoinitiator. This composite system allows the resin to enhance adhesion while the monomer content and formulation balance maintain low viscosity suitable for ink-jet printing, effectively resolving the contradiction through material composition.
2Speed
If passive resin is incorporated into ink-jet ink to enhance adhesion and cure speed, then cure speed is improved, but viscosity increases which precludes effective use in ink-jet printing
Solution Approach 1:
The patent optimizes the molecular weight parameter of the passive resin (1,500-70,000) and controls its concentration (2-15 wt%) to achieve the desired cure speed without excessive viscosity increase. This parameter control allows the resin to accelerate curing while maintaining ink-jet compatibility.
Solution Approach 2:
The composite formulation combines thermoplastic acrylic resin with monofunctional (meth)acrylate monomers and photoinitiator, creating a system where the resin provides cure speed enhancement while the overall composition maintains low viscosity through balanced ingredient selection and formulation.
3Reliability
If traditional passive materials are used to enhance adhesion, then adhesion is improved, but solution viscosity becomes too high for effective ink-jet ink formulation
Solution Approach 1:
The patent fundamentally changes the molecular weight parameter of passive materials from traditional high values to a specific range (1,500-70,000). This parameter change reduces solution viscosity significantly while maintaining adhesion performance, making the material compatible with ink-jet formulation requirements and resolving the contradiction between reliability and ease of manufacture.
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 ink achieves low viscosity suitable for high-speed printing, improved adhesion, and enhanced cure speed, with the ability to form three-dimensional articles through vacuum forming, while maintaining the benefits of radiation curing without the limitations of traditional ink-jet inks.
Implementation Method 1
The ink is hardened by irradiation of radiation or heat, and the ratio of total thickness of the ink layer to total thickness of the substrate is from 0.40 to 0.05
Implementation Method 2
the use of passive or inert resins to enhance adhesion of radiation cured coatings to plastics substrates is well known in screen-ink technology, in particular the use of thermoplastic acrylic resins is common to improve cure speed and adhesion
Implementation Method 3
This type of ink has the advantage that it is not necessary to evaporate the liquid phase to dry the print; instead the print is exposed to radiation to cure or harden it
Data Source
AI summary
This invention relates to a printing ink and in particular to an ink for ink-jet printing which is cured by irradiation. The ink comprises at least one radiation-curable monomer; at least one passive thermoplastic resin; at least one radical photoinitiator; and at least one colouring agent; wherein the ink has a viscosity of less than 100 mPas at 25ºC, and wherein the at least one passive resin is present at 2 to 15 wt% based on the total weight of the ink and has a molecular weight of 1,500 to 70,000.