Ink Jet Recording Method for Soft Packaging Films
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Solution Overview
Problem
Ink jet recording methods face challenges in forming high-quality images on soft packaging films with water-based inks, particularly in achieving good adhesion and durability due to bleeding issues caused by solvent content in the ink layers.
Innovation Solution
An ink jet recording method involving a first ink composition with resin particles, organic solvent, and water, where 80% or more of water is evaporated to form a stable undercoat layer, followed by a second ink composition that dissolves or swells the resin particles in the first layer, ensuring adhesion and suppressing bleeding, with organic solvents having a normal boiling point above 250°C limited to 2% or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the lower layer is dried completely to suppress bleeding, then bleeding is reduced, but adhesion between layers deteriorates
Solution Approach 1:
The patent changes the parameter of organic solvent content in the ink composition. By formulating the ink with specific organic solvents (e.g., esters, ketones, carbonates) in controlled amounts (0.1-20 mass%), the ink maintains optimal balance between bleeding suppression and adhesion. The organic solvent evaporates at controlled rates, preventing excessive drying that would harm adhesion while still reducing bleeding.
Solution Approach 2:
The patent uses composite ink formulations combining multiple components: water (50-90 mass%), organic solvents (0.1-20 mass%), resins (1-30 mass%), and coloring materials. This composite structure allows the ink to exhibit both bleeding suppression properties (through controlled evaporation) and adhesion properties (through resin content and organic solvent selection), resolving the contradiction between these two requirements.
2Strength
If organic solvent content is increased to improve adhesion, then adhesion improves, but bleeding increases
Solution Approach 1:
The patent precisely controls the organic solvent content parameter within 0.1-20 mass% of the total ink composition. This optimized range provides sufficient adhesion through moderate organic solvent content while preventing excessive bleeding. The specific selection of organic solvents (esters, ketones, carbonates with controlled boiling points) further refines this balance.
Solution Approach 2:
The patent applies different functional components in specific proportions: water-based carriers provide bulk and controlled evaporation, while organic solvents (1-20 mass%) provide localized adhesion enhancement at the ink-substrate interface. The resin component (1-30 mass%) provides localized binding strength. This spatial and functional differentiation resolves the contradiction between adhesion and bleeding.
3Reliability
If water-based ink is used for food packaging safety, then safety is improved, but drying performance deteriorates
Solution Approach 1:
The patent creates a composite water-based ink formulation combining water (50-90 mass%) for safety with organic solvents (0.1-20 mass%) for enhanced drying performance. The organic solvents (esters, ketones, carbonates) evaporate more readily than water alone, improving drying speed while maintaining the water-based safe formulation. Resins (1-30 mass%) provide film formation and adhesion during the drying process.
Solution Approach 2:
The patent modifies the evaporation rate parameter by introducing organic solvents with controlled boiling points (e.g., ethyl acetate 77°C, acetone 56°C, dimethyl carbonate 90°C) into the water-based ink. This creates a multi-component evaporation system where organic solvents evaporate first, followed by water, achieving fast drying performance while maintaining food safety through water-based formulation.
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 method achieves excellent durability and suppressed bleeding by enhancing adhesion between layers and maintaining good drying properties, even on non-ink absorption recording media like soft packaging films.
Implementation Method 1
first drying in which 80% by mass or more of water contained in the first ink composition of the first image layer is evaporated
Implementation Method 2
a second ink composition that contains water, and an organic solvent by which the resin particles contained in the first ink composition dissolve or swell
Implementation Method 3
an organic solvent by which the resin particles contained in the first ink composition dissolve or swell
Data Source
AI summary
An ink jet recording method includes: forming a first image layer by ejecting a first ink composition that contains resin particles, an organic solvent, and water on a recording medium by an ink jet method; first drying in which 80% by mass or more of water contained in the first ink composition of the first image layer is evaporated; and forming a second image layer by ejecting a second ink composition that contains water, and an organic solvent by which the resin particles contained in the first ink composition dissolve or swell on the first image layer subjected to the first drying by the ink jet method, in which the content of an organic solvent having a normal boiling point of higher than 250° C. in the first ink composition and the second ink composition is 2% by mass or less, respectively.