Acrylate Ink Composition for Digital Offset Lithography
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Solution Overview
Problem
Existing digital offset lithography printing systems face challenges with ink delivery, solubility in dampening fluids, ghosting issues, high manufacturing costs, and inefficient image transfer due to the limitations of current offset-type inks.
Innovation Solution
The development of an acrylate ink composition with specific formulations, including a combination of trifunctional and tetrafunctional polyester acrylate oligomers, photoinitiators, and rheology modifiers, which provides near-zero shear viscosity and high tack at various temperatures, enabling efficient ink transfer without pre-curing and improved compatibility with digital offset lithography systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If offset-type inks are used in digital offset lithography printing systems, then the system can operate with a non-patterned reimageable surface, but the inks exhibit poor delivery performance via anilox roller systems and show solubility in dampening fluids
Solution Approach 1:
The patent modifies the chemical composition parameters of the ink by incorporating specific acrylic oligomers with controlled functionality (difunctional, trifunctional, tetrafunctional) and molecular weight ranges. These parameter changes in the ink formulation improve delivery performance via anilox rollers while maintaining compatibility with the digital offset lithography system and reducing solubility in dampening fluids.
2Productivity
If related art offset inks are used, then digital printing can be performed, but image background and ghosting issues occur
Solution Approach 1:
The patent changes the chemical parameters of the ink composition by using specific acrylic oligomers with controlled hydrophobicity and viscosity characteristics. These parameter modifications prevent unwanted ink migration and background formation, thereby eliminating ghosting issues while maintaining digital printing productivity.
3Productivity
If related art inks are used, then printing can be performed, but manufacturing and operational costs are high
Solution Approach 1:
The patent employs acrylic oligomers that can be formulated into single-use or limited-life ink compositions optimized for digital offset printing. These inks are designed to perform effectively for their intended lifespan without requiring expensive additives or complex formulations, thereby reducing manufacturing costs while maintaining printing productivity.
4Productivity
If related art inks are used, then digital lithography printing can be performed, but image transfer efficiency is low
Solution Approach 1:
The patent optimizes the viscosity and surface tension parameters of the ink by selecting specific acrylic oligomers with controlled molecular weights and functionality. These parameter adjustments enhance the ink's ability to transfer efficiently from the anilox roller to the substrate, improving image transfer efficiency while maintaining high printing speed.
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 acrylate ink composition enhances ink delivery, reduces solubility in dampening fluids, minimizes ghosting, lowers manufacturing costs, and improves image transfer efficiency, addressing the limitations of traditional inks in digital offset lithography.
Implementation Method 1
between 5 and 10% by weight photoinitiator, wherein an effective amount of the trifunctional acrylate monomer in combination with the tetrafunctional polyester acrylate oligomer, and the optional difunctional polyester acrylate oligomer provides the ink composition with a near-zero shear (1 rad/s) viscosity
Implementation Method 2
a near-zero shear (1 rad/s) viscosity of between 2×10^6 cP and 5×10^7 cP at 25° C., and between 2×10^5 cP and 4×10^6 cP at 60° C.
Data Source
AI summary
An ink composition, including 20% or less pigment, 10% or less dispersant, between 50% and 75% acrylate with acrylate being a mixture of a trifunctional acrylate monomer, a tetrafunctional polyester acrylate oligomer, and an optional difunctional polyester acrylate oligomer, 12% or less photoinitiator, and wherein an effective amount of the trifunctional acrylate monomer in combination with the tetrafunctional polyester acrylate oligomer, and the optional difunctional polyester acrylate oligomer provides the ink composition with a near-zero shear viscosity between 2×106 cP and 5×107 cP at 25° C., and between 2.×105 cP and 4.×106 cP at 60° C., and a 60 second tack between 40 and 65 g-m at 25° C., and between 10 and 20 g-m at 60° C., and an energy of activation between 15 and 180 at kJ/mol at 1 rad/s, and between 40 and 120 at kJ/mol at 100 rad/s.