White Ink Coating Adhesion on Non-Absorbent Films
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Solution Overview
Problem
Existing printing methods for non-absorbent or poorly absorbent printing media, such as transparent flexible packing films, face challenges in achieving high adhesion between white ink coatings and protective films, leading to issues with laminate peeling resistance and opacity.
Innovation Solution
A printing method involving the application of non-white and white ink compositions with limited organic solvent content, where the mass ratio of white ink to non-white ink in the superimposed region is 1.5 or more, applied using an ink jet printing apparatus, with optional post-application drying to enhance adhesion and opacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If white ink composition is applied to form an opaque coating on non-absorbent printing media, then opacity is improved, but adhesion between the white ink coating and protective film deteriorates (laminate peeling occurs)
Solution Approach 1:
The invention changes the chemical composition parameters of the white ink by strictly limiting organic solvent content to 15% or less (preferably 5% or less) and controlling the mass ratio of white ink to non-white ink to 1.5 or more. This parameter optimization ensures sufficient opacity while preventing excessive solvent that would compromise adhesion and cause laminate peeling.
Solution Approach 2:
The invention uses a composite ink system consisting of white ink composition applied over non-white ink composition. By controlling the interaction between these two ink layers with specific mass ratios and solvent limitations, the system achieves both opacity and adhesion that neither ink alone could provide.
2Manufacturing precision
If organic solvent content in ink composition is increased to improve ink flow and coverage, then printing quality is improved, but adhesion between ink coating and protective film deteriorates
Solution Approach 1:
The invention optimizes the organic solvent content parameter to 15% or less (preferably 5% or less) in the white ink composition. This parameter change maintains sufficient ink flow and coverage for quality printing while preventing excessive solvent that would interfere with protective film adhesion and cause laminate peeling.
3Illumination intensity
If white ink is applied in large amounts to ensure opacity, then opacity is improved, but laminate peel resistance deteriorates
Solution Approach 1:
The invention changes the mass ratio parameter of white ink to non-white ink to 1.5 or more, which provides sufficient opacity. Simultaneously, it limits organic solvent content to 15% or less, ensuring that even at this elevated ratio, the coating maintains proper adhesion properties and prevents laminate peeling.
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 ensures high laminate peel resistance and opacity by controlling the ink composition and application ratio, allowing for efficient printing on non-absorbent media while maintaining image quality and resistance to rubbing.
Implementation Method 1
The non-white ink application step and the white ink application step each may be performed by ejecting the corresponding ink composition from an ink jet head
Implementation Method 2
the printing method may further include a post-application drying step of heating the printing medium with an infrared heater after the white ink application step
Data Source
AI summary
A printing method for printing a printing medium includes a non-white ink application step of applying an aqueous non-white ink composition containing a non-white coloring material onto the printing medium, and a white ink application step of applying an aqueous white ink composition containing a white coloring material onto the non-white ink composition on the printing medium to form a superimposed region. The non-white ink composition and the white ink composition each have an organic solvent content limited to 15% or less relative to the total mass of the corresponding ink composition. The mass ratio of the white ink composition to the non-white ink composition in the superimposed region is 1.5 or more in a portion to which the non-white ink composition is applied in an amount largest in the superimposed region.