Ink Composition for Clear Layer Adhesion
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Solution Overview
Problem
Existing ink compositions for forming clear layers in ink-jet printing fail to achieve sufficient adhesiveness with substrates, recording layers, and clear layers, as well as adequate overcoating and refinishing properties, limiting their design and durability characteristics.
Innovation Solution
An ink composition with specific surface energy ranges for substrates and recording layers, combined with a clear layer ink having controlled contact angles and containing specific pigments, polymerizable compounds, and photopolymerization initiators, is used to form a clear layer that enhances adhesiveness and refinishing properties through energy ray-curable processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If existing ink compositions are used for forming clear layers, then the coating process can be completed, but the adhesiveness with substrate, recording layer and clear layer is insufficient
Solution Approach 1:
The patent applies parameter changes by carefully controlling the surface free energy of the substrate (30-45 mJ/m²) and the surface tension of the clear layer ink composition (20-35 mN/m) to achieve optimal adhesiveness. This involves selecting specific polymerizable compounds with appropriate functional groups and adjusting their proportions to tune the surface properties of the ink composition, thereby resolving the contradiction between achieving sufficient adhesiveness and maintaining reliable coating quality.
Solution Approach 2:
The patent uses composite materials by formulating the clear layer ink composition with multiple polymerizable compounds including (meth)acrylates, vinyl esters, and carboxylic acid esters in specific proportions. This composite approach combines materials with different adhesive properties and curing characteristics to achieve both strong adhesion to substrate/recording layer and reliable overcoating performance, resolving the technical contradiction.
2Ease of manufacture
If existing ink compositions are used for forming clear layers, then the coating can be applied, but the overcoating property and refinishing properties are insufficient
Solution Approach 1:
The patent applies parameter changes by controlling the viscosity and surface tension of the clear layer ink composition through selective use of polymerizable compounds with different molecular weights and functional groups. The surface tension is maintained at 20-35 mN/m and viscosity at 4-50 mPa·s to ensure both easy overcoating application and high refinishing quality, resolving the contradiction between ease of manufacture and manufacturing precision.
Solution Approach 2:
The patent applies local quality by creating different functional zones within the clear layer through the use of multiple polymerizable compounds that cure at different rates and provide different local properties. The composition enables the clear layer to have both good flow characteristics for overcoating and refined surface properties after curing, addressing the contradiction between overcoating ease and refinishing precision.
3Adaptability or versatility
If double coating is performed to form thick-coated portion for three-dimensionality, then design characteristics are enhanced, but the adhesiveness and refinishing properties become insufficient
Solution Approach 1:
The patent applies universality by formulating a clear layer ink composition that simultaneously provides multiple functions: strong adhesion to substrate and recording layer, good overcoating properties, and excellent refinishing characteristics. The multi-functional polymerizable compound system ensures that even when double coating is performed for three-dimensional effects, the adhesiveness and refinishing properties remain sufficient, resolving the contradiction between design versatility and adhesion strength.
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 excellent adhesiveness and overcoating properties, enabling the creation of printed articles with improved design characteristics, including three-dimensionality and pattern formation, while maintaining long-term durability and weather resistance.
Implementation Method 1
an ink composition for forming a clear layer... energy ray-curable ink composition... containing specific pigments, polymerizable compounds, and photopolymerization initiators, is used to form a clear layer that enhances adhesiveness and refinishing properties through energy ray-curable processes
Data Source
Figure 1
AI summary
Disclosed is an ink composition for clear layer formation having excellent adhesion properties on substrates, recording layers, and clear layers, as well as excellent overcoat characteristics and refinishing properties. Further disclosed are a coating method for the ink composition, and a printed article formed using the ink composition. The ink composition for clear layer formation is used for forming at least one clear layer on a substrate, or on a printed article on which a printed coating film is formed on a substrate as a recording layer. The ink composition for clear layer formation is characterised in that: the surface free energy of the substrate is 30-45 (mJ/m2); the surface free energy of the recording layer is 40-50 (mJ/m2); the contact angle of the ink composition to the substrate is 30-65 degrees, the contact angle of the ink composition to the recording layer is 40-55 degrees, and the contact angle of the ink composition to the clear layer is 45-60 degrees.