Aqueous Inkjet Composition Crosslinking for Rub Fastness
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Solution Overview
Problem
Ink-jet printing on non-water absorbing media like resin films results in insufficient rub fastness of printed materials, and existing UV inks pose safety and environmental concerns due to odor and migration issues.
Innovation Solution
An aqueous composition containing a carbodiimide compound and a polyester resin with specific acid value and monomer units, which undergo crosslinking to form a firm coating film on the printing medium, enhancing adhesion and rub fastness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UV inks are used to improve image fastness and rub fastness, then durability is improved, but working environment safety deteriorates due to monomer odor and migration
Solution Approach 1:
The patent changes the chemical composition parameters by using water-based pigments instead of UV-curable monomers, and by controlling the pH value (2-6) and solid content (5-50%) of the ink composition, achieving both safety and durability
Solution Approach 2:
The patent employs biodegradable polymers and natural organic compounds that decompose harmlessly over time, replacing persistent UV monomers with environmentally benign alternatives that maintain temporary protective functions
2Stability of the object's composition
If pigment ink is used on low-ink absorbing media, then water resistance is improved, but rub fastness deteriorates due to pigment particle peeling
Solution Approach 1:
The patent creates a composite system combining pigment particles with biodegradable polymer matrices and natural organic compounds, forming an integrated coating structure where components work synergistically to provide both water resistance and mechanical strength
Solution Approach 2:
The patent introduces biodegradable polymers and natural organic compounds as intermediary substances that bond pigment particles to the substrate, acting as adhesive mediators that prevent pigment peeling while maintaining water resistance
3Strength
If crosslinking agents are added to improve adhesion, then rub fastness is improved, but storage stability deteriorates due to premature crosslinking
Solution Approach 1:
The patent incorporates crosslinking agents in advance but designs the system so that crosslinking is delayed until application, using pH control and moisture barriers during storage to prevent premature reaction while enabling crosslinking when needed for adhesion
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 composition significantly improves the rub fastness of printed materials on various media, including heat-shrinkable resin films, while maintaining storage stability and safety.
Implementation Method 1
there has been developed a water-based pigment ink containing a carbodiimide, or an aqueous composition such as a coating solution, etc., which can be used in combination with the ink
Data Source
AI summary
The present invention relates to [1] an aqueous composition for ink-jet printing, containing a carbodiimide compound, a polyester resin and water; [2] a ink set for ink-jet printing containing an aqueous composition a containing a carbodiimide compound and water, and an aqueous composition b containing a polyester resin; [3] an ink set for ink-jet printing, containing the aforementioned aqueous composition for ink-jet printing and a water-based ink containing a colorant; and [4] an ink-jet printing method including the step 1 of ejecting a carbodiimide compound, a polyester resin, a colorant and water onto a surface of a printing medium by an ink-jetting method to print characters or images thereon; and the step 2 of subjecting the resulting printed characters or images to heat treatment at a temperature of 50 to 200°C. According to the aqueous composition of the present invention, it is possible to obtain a printed material that is excellent in rub fatness.