Ink Composition with Sulfide-Bonded Resin for Ejection Stability
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Solution Overview
Problem
Conventional inkjet recording methods on non-water-absorptive media, such as plastic films, face challenges with ink ejection performance and image adhesion due to increased ink viscosity and surface localization of polymers, leading to insufficient film strength and adhesion.
Innovation Solution
An ink composition comprising a (meth)acrylic resin with a multifunctional thiol structure, connected by sulfide bonds, and including specific (meth)acrylic repeating units, a polymerization initiator, and a polymerizable compound, which maintains low viscosity and enhances adhesion by distributing the polymer chains uniformly, thereby improving ejection stability and film strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polymer compound with amide structure and branched structure is used to improve adhesion and film strength, then adhesion and film strength are improved, but ink viscosity increases and ejection performance deteriorates
Solution Approach 1:
The patent changes the chemical structure parameters of the polymer by replacing amide groups with carboxyl groups and adjusting the branching structure. This parameter change allows the polymer to maintain film strength while reducing viscosity improvement, resolving the contradiction between film strength and ejection performance
Solution Approach 2:
The patent uses a composite polymer structure combining linear chains with controlled branching points. This composite structure achieves both the mechanical strength needed for film formation and the flow properties needed for inkjet ejection, resolving the contradiction between film strength and ejection performance
2Strength
If a polymer with fluorine-substituted hydrocarbon group, siloxane skeleton, or long chain alkyl group is used to improve scratch resistance and anti-blocking properties, then scratch resistance and anti-blocking properties are improved, but adhesion to recording medium deteriorates
Solution Approach 1:
The patent applies local quality by concentrating surface-active groups (carboxyl and hydroxyl groups) at the polymer surface while maintaining a backbone structure that provides mechanical strength. This local concentration of functional groups improves adhesion without sacrificing scratch resistance
Solution Approach 2:
The patent changes the surface chemistry parameters by introducing carboxyl and hydroxyl groups that can form hydrogen bonds and electrostatic interactions with the recording medium surface, thereby improving adhesion while maintaining the mechanical properties through the polymer backbone structure
3Productivity
If polymerization initiator concentration is increased to improve curing sensitivity and recording speed, then curing sensitivity and recording speed are improved, but ink composition complexity and control difficulty increase
Solution Approach 1:
The patent uses a polymer that serves multiple functions: it acts as both the film-forming component and the curing substrate. The polymer contains built-in polymerizable groups that react with the initiator, eliminating the need for separate sensitizer components and simplifying the overall ink composition while maintaining high curing sensitivity
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 composition achieves high ejection stability and excellent film strength with improved adhesion to the recording medium, maintaining low viscosity and preventing surface localization of the polymer, resulting in enhanced image quality on non-water-absorptive media.
Implementation Method 1
an ink is ejected and then irradiated with a radiation to cure an ink droplet
Data Source
AI summary
An ink composition for inkjet recording includes a (meth)acrylic resin, a polymerization initiator, and a polymerizable compound. The (meth)acrylic resin includes a skeleton structure derived from a multifunctional thiol that is trifunctional to hexafunctional, and plural polymer chains connected to the skeleton structure by a sulfide bond, each of the plural polymer chains including at least two kinds of (meth)acrylic repeating units selected from the group consisting of a repeating unit derived from a (meth)acrylate having a C1-C8 linear, C3-C8 branched, C3-C8 alicyclic, or C6-C8 aromatic hydrocarbon group which may include an oxygen atom, a repeating unit derived from a (meth)acrylate having a C9-C10 alicyclic hydrocarbon group, and a repeating unit derived from (meth)acrylic acid, in an amount of more than 90 mol % with respect to the total repeating units in the polymer chain. An inkjet recording method uses the ink composition and a printed matter is printed with the ink composition.