Continuous Ink Composition for Alcohol-Resistant Fast-Drying Marking
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Solution Overview
Problem
Existing continuous inkjet inks face challenges in achieving solvent resistance, particularly to alcohols, and health and safety concerns arise from the use of methyl ethyl ketone (MEK) as a solvent, while maintaining adhesion and fast drying properties.
Innovation Solution
An ink composition comprising volatile C5 ketones, cosolvents, binder resins, and colorants, specifically using methyl propyl ketone, ethanol, copolymers of vinyl chloride and vinyl acetate, and Solvent Black 27, with optional additives, to enhance solvent resistance and adhesion on various substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If methyl ethyl ketone (MEK) is used as the solvent, then fast drying time and good adhesion are achieved, but health and safety concerns and regulatory issues arise
Solution Approach 1:
The patent changes the chemical parameters of the solvent system by replacing MEK with volatile C5 ketones (methyl propyl ketone, methyl isopropyl ketone, or diethyl ketone) in specific proportions (30-80% by weight). This substitution maintains the fast-drying characteristic and adhesion properties while eliminating the health and safety concerns associated with MEK, as the C5 ketones have higher flash points and lower toxicity.
Solution Approach 2:
The patent employs a cosolvent system containing alcohols (ethanol, n-propanol, isopropanol) and esters (ethyl acetate, isopropyl acetate) that are readily biodegradable and environmentally friendly. These cosolvents (3-45% by weight) assist the main solvent in achieving proper drying characteristics while being less harmful to the environment and human health compared to traditional MEK-based formulations.
2Object-affected harmful factors
If the ink formulation is changed to avoid MEK, then health and safety concerns are reduced, but solvent resistance to alcohols deteriorates
Solution Approach 1:
The patent employs a composite binder resin system combining multiple resin types (vinyl chloride-vinyl acetate copolymers, polyesters, co-polyesters) in specific proportions. This composite resin system creates a cross-linked network structure that provides excellent resistance to alcohol solvents while maintaining compatibility with the alternative solvent system (C5 ketones + alcohol cosolvents), thus achieving both health safety and solvent resistance requirements.
Solution Approach 2:
The patent optimizes the molecular weight, functional group content, and composition ratios of the binder resins to achieve the desired balance between adhesion and solvent resistance. By carefully controlling the resin parameters and their interactions with the solvent system, the ink forms a dried film with enhanced chemical resistance to alcohols despite using a MEK-free formulation.
3Reliability
If the ink composition is optimized for solvent resistance, then markings resist alcohol penetration, but adhesion to diverse substrates may be compromised
Solution Approach 1:
The patent utilizes the cosolvent system (alcohols and esters) to modify the local properties of the ink formulation during the drying process. The cosolvents influence the evaporation rate and film formation characteristics, creating a gradient structure in the dried film that enhances both adhesion to the substrate and resistance to alcohol penetration. This local optimization allows the ink to perform well on diverse substrates while maintaining solvent resistance.
Solution Approach 2:
The patent employs a composite binder resin system combining multiple resin types (vinyl chloride-vinyl acetate copolymers, polyesters, co-polyesters) in specific proportions. This composite resin system creates a cross-linked network structure that provides excellent resistance to alcohol solvents while maintaining compatibility with the alternative solvent system (C5 ketones + alcohol cosolvents), thus achieving both health safety and solvent resistance requirements.
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 provides excellent solvent resistance to alcohols, adheres well to diverse substrates, and maintains fast drying properties without using MEK, suitable for industries like electronics, cosmetics, and pharmaceuticals.
Implementation Method 1
the ink composition comprises (a) a solvent comprising one or more volatile C5 ketones... The ink composition provides excellent solvent resistance... maintains fast drying properties
Implementation Method 2
one or more binder resins selected from copolymers of vinyl chloride and vinyl acetate... adheres well to diverse substrates
Implementation Method 3
the solvent resistivity of a marking formed from an ink depends on both the binder resin and the solvent used in the ink formulation, with different combinations of binder resin and solvent producing dried films with different microstructures. These different microstructures arise from the differing drying behaviour of the inks
Data Source
AI summary
Described herein are ink jet ink compositions for continuous inkjet printing comprising a solvent, a cosolvent, a binder resin, and a colorant. Such ink jet ink compositions are resistant to organic solvents, such as alcohols, and are intended for use in industries where such solvents are commonly used, such as electronics, cosmetics, healthcare, and pharmaceuticals.