High-Speed Screen Printing Ink Composition for Sharp Pattern Definition
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Solution Overview
Problem
High-speed screen printing technologies face challenges in simultaneously achieving high-quality, high-definition printing of both fine patterns and wide-area solid patterns in a single step, particularly with cylinder press printers, due to issues like spreading and bleeding caused by low-viscosity inks, and high-viscosity inks failing to maintain even coverage at rapid squeegee speeds.
Innovation Solution
An ink composition with a solvent boiling point of at least 170°C at 70 wt% and a prepolymer or polymer with a weight-average molecular weight of at least 2000, having a viscosity of 6-30 Pa·s and a thixotropic index of 2.0-8.0, which allows for stable flow and adhesion, enabling high-quality printing at squeegee speeds of 350 mm/sec without spreading or bleeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If low-viscosity ink is used to enable high-speed printing, then printing speed is improved, but image sharpness deteriorates due to spreading and bleeding
Solution Approach 1:
The patent applies parameter changes by carefully controlling the viscosity of the ink composition within a specific range (6-30 Pa·s at 25°C) and the molecular weight of the binder resin (2000-100000). This optimized parameter combination allows the ink to maintain adequate flow at high printing speeds while preventing excessive spreading and bleeding, thereby resolving the contradiction between printing speed and image sharpness
Solution Approach 2:
The patent uses composite materials by combining specific types of binder resins (polyester resin, acrylic resin, polyurethane resin, or epoxy resin) with carefully selected solvents and pigments. This composite ink formulation achieves both the flow properties needed for high-speed printing and the adhesion properties that prevent spreading, thus maintaining image sharpness at high printing speeds
2Manufacturing precision
If high-viscosity ink is used to prevent spreading and bleeding, then image sharpness is improved, but printing speed deteriorates due to insufficient ink flow at rapid squeegee speeds
Solution Approach 1:
The patent applies parameter changes by precisely controlling the viscosity within the range of 6-30 Pa·s at 25°C, which is higher than conventional inks but optimized for high-speed screen printing. This parameter optimization ensures the ink has sufficient viscosity to prevent spreading while maintaining adequate flowability at rapid squeegee speeds of 350 mm/sec or more, thus resolving the contradiction between image sharpness and printing speed
Solution Approach 2:
The patent applies dynamics by considering the ink's behavior under different shear conditions. The ink composition is designed to exhibit appropriate rheological properties that allow it to flow smoothly during high-speed application while maintaining shape and preventing spreading after deposition, thus achieving both high printing speed and image sharpness
3Stability of the object's composition
If ink viscosity is increased to maintain coverage at high speed, then coverage uniformity is improved, but spreading and bleeding increase
Solution Approach 1:
The patent applies parameter changes by optimizing the viscosity to a specific range (6-30 Pa·s) and controlling the binder resin content (7-70 wt%). This balanced parameter combination ensures the ink maintains uniform coverage during high-speed printing while preventing excessive spreading and bleeding, thus resolving the contradiction between coverage uniformity and pattern definition
Solution Approach 2:
The patent uses composite materials by formulating an ink composition with specific ratios of binder resin (7-70 wt%), solvent (20-80 wt%), and pigment (1-50 wt%). This composite formulation achieves the right balance between coverage uniformity and pattern definition by selecting resins that provide both adhesion and controlled flow characteristics
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
Enables high-quality, high-definition printing of fine and solid patterns in a single step with reduced edge spreading, maintaining image sharpness and stability across multiple prints, even at high speeds, using a cylinder press or semi-automatic screen printers.
Implementation Method 1
having a thixotropic index (TI Value) of 2.0 to 8.0
Data Source
AI summary
An ink composition for high-speed screen printing, includes a solvent with a boiling point of not less than 170° C. at not less than 70 wt % of the total solvent, and a prepolymer or polymer with a weight-average molecular weight of not less than 2000 at not less than 7 wt % with respect to the total ink composition, and having a viscosity of not less than 6 Pa·s and less than 30 Pa·s as measured with a BH-type rotating viscosimeter at 25° C., and a thixotropic index (TI value) of 2.0 to 8.0, the measured flow radius value of 14.0 to 24.0 mm after 1 minute from the start of measurement by a flow property measuring method using a spread meter at 25° C. according to JIS K5701-1:2000.