Polyurethane Ink Composition for High-Speed Printing
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Solution Overview
Problem
High-speed ink jet printing faces challenges with lower image quality compared to offset lithography and gravure, due to ink spreading and water saturation issues, leading to reduced durability and increased costs, especially when using water-based inks on coated papers, which are prone to damage and distortion.
Innovation Solution
An ink composition incorporating a polyurethane with a peak average molecular weight range of 10,000 g/mol to 40,000 g/mol, along with a solvent and a colorant, providing a binder for improved durability and viscosity control, allowing for high-speed printing without fuzziness or intercolor mixing, and including surfactants and humectants for enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If water-based ink is used for high-speed ink jet printing, then printing speed is improved, but image quality deteriorates due to ink spreading and water saturation
Solution Approach 1:
The patent changes the chemical composition parameters of the ink by incorporating polyurethane polymers with specific molecular weights (10,000-100,000 g/mol) and controlling the ratio of colorant to polyurethane (1:4 to 4:1 by weight). This parameter optimization allows the ink to maintain low viscosity for high-speed jetting while preventing excessive spread on the substrate, thereby resolving the contradiction between printing speed and image quality
Solution Approach 2:
The patent creates a composite ink formulation by combining colorant, polyurethane polymer, and solvent in specific proportions. The polyurethane acts as a binder that holds the colorant particles together, forming a composite structure that reduces ink spread while maintaining flowability. This composite approach enables both high-speed deposition and sharp image edges
2Reliability
If ink coverage is increased for color printing, then color quality is improved, but drop spread increases causing fuzzy images
Solution Approach 1:
The patent optimizes the concentration parameters by controlling the colorant to polyurethane ratio (1:4 to 4:1 by weight) and total solids content (5-50%). This parameter control allows higher ink coverage for better color quality while the polyurethane binder prevents individual colorant particles from spreading, maintaining image sharpness even at high coverage levels
Solution Approach 2:
The polyurethane polymer acts as a structural template or 'copy' that replicates the desired drop shape and prevents deviation. When ink is deposited, the polyurethane framework maintains the intended dot geometry, ensuring that increased coverage does not lead to proportional increases in spread, thus preserving image sharpness
3Ease of manufacture
If traditional ink formulation is used, then cost is reduced, but durability against mechanical abrasion and water exposure is poor
Solution Approach 1:
The patent formulates a composite ink system where polyurethane polymer (10,000-100,000 g/mol) serves as a durable binder matrix embedding colorant particles. This composite structure provides inherent resistance to mechanical abrasion and water exposure while using commercially available materials and straightforward formulation processes, balancing cost-effectiveness with enhanced durability
Solution Approach 2:
The polyurethane polymer forms a cohesive matrix that encapsulates colorant particles, creating a spherical or rounded protective structure around each ink deposit. This curved, encapsulating structure resists mechanical breakdown from abrasion and prevents water penetration, significantly improving durability without requiring expensive specialized materials
4Adaptability or versatility
If printed paper web is exposed to moisture, then water saturation occurs leading to wrinkling and distortion
Solution Approach 1:
The polyurethane polymer in the ink formulation acts as an intermediary barrier between the colorant and the paper substrate. This intermediary layer controls moisture interaction, allowing the ink to adhere properly to various paper types while preventing excessive water saturation that would cause wrinkling or distortion, thus maintaining paper integrity across different paper compositions
Solution Approach 2:
The patent adjusts the solvent composition and polyurethane concentration parameters to optimize moisture interaction. By controlling the ratio of volatile to non-volatile components and the total solids content (5-50%), the ink dries at controlled rates that prevent paper saturation and distortion while ensuring proper adhesion, enabling versatile application across different paper types without compromising paper stability
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 immediate and long-term durability, preventing smearing and offsetting during high-speed printing, maintaining image quality, and reducing costs by stabilizing the colorant on the substrate and resisting mechanical abrasions.
Implementation Method 1
The ink composition achieves immediate and long-term durability, preventing smearing and offsetting during high-speed printing, maintaining image quality, and reducing costs by stabilizing the colorant on the substrate
Implementation Method 2
providing a binder for improved durability and viscosity control, allowing for high-speed printing without fuzziness or intercolor mixing
Implementation Method 3
Long term durability refers to the ability of the ink to remain on the final printed product and resist potential damage caused by post-printing water exposure, highlighting markers, and other mechanical abrasions to the printed document
Data Source
AI summary
According to one aspect, an ink composition includes a colorant, a polyurethane having a peak average molecular weight range of from about 25,000 g/mol to about 35,000 g/mol, and a solvent. The ink composition has a total solids content of less than about 12% by weight, and a ratio of colorant to polyurethane between about 1:1 and 1:2 by weight.