Aqueous Pigment Concentrate for Inkjet Printing Stability
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Solution Overview
Problem
Aqueous inkjet inks used in corrugated board printing face challenges such as short open-time issues, limited heat abrasion resistance, and instability of physical-chemical properties, particularly when used in in-line printing applications within corrugated board production lines, leading to issues like nozzle clogging and poor image quality.
Innovation Solution
An aqueous pigment concentrate comprising 5-40% pigments, 0.5-10% pigment dispersing agents, and 0.1-10% non-ionic surfactants with a hydrophilic-lipophilic balance (HLB) value of at least 12, which forms an effective organic shell around pigment particles, reducing dewetting and coagulation, and is used to create an aqueous ink with improved stability and performance for inkjet printing on corrugated boards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional aqueous inkjet inks are used in in-line printing on corrugated board, then printing can be performed, but the inks exhibit short open-time issues, poor heat abrasion resistance, and instability of physical-chemical properties leading to nozzle clogging and poor image quality
Solution Approach 1:
The patent modifies the chemical composition parameters of the ink by introducing a specific polymeric dispersing agent with controlled molecular weight (10,000-100,000 g/mol) and functional groups, along with optimized pigment concentration (5-40 wt%) and surfactant content. These parameter changes improve ink stability, reduce nozzle clogging, and eliminate start-up issues while maintaining printing performance in in-line corrugated board production
Solution Approach 2:
The invention creates a composite ink system combining pigment particles, polymeric dispersing agents with specific functional groups (carboxylic acid, hydroxyl, or amine), and non-ionic surfactants. This composite formulation enhances heat abrasion resistance and physical-chemical stability, allowing continuous operation without nozzle clogging or image quality degradation
2Manufacturing precision
If pigment concentration in aqueous ink is increased to improve color strength, then image quality improves, but viscosity increases leading to poorer jetting performance and potential nozzle clogging
Solution Approach 1:
The patent optimizes the balance between pigment concentration (5-40 wt%) and polymeric dispersing agent content, with the dispersing agent comprising 0.1-10 wt% of the total ink composition. The molecular weight control (10,000-100,000 g/mol) and functional group selection create optimal steric and electrostatic repulsion, maintaining low viscosity even at high pigment concentrations, thus enabling both high image quality and smooth jetting performance
Solution Approach 2:
The polymeric dispersing agent acts as an intermediary between pigment particles and the aqueous medium, providing steric and electrostatic stabilization. This mediator prevents pigment aggregation, maintains uniform dispersion at high concentrations, and ensures adequate fluidity for jetting, thereby resolving the conflict between color strength and jetting performance
3Productivity
If in-line printing is implemented in corrugated board production to eliminate analog flexography, then manufacturing cost and production flexibility improve, but the ink must meet exceptional requirements including high frequency jettability, good drying performance, high stability, and high water resistance
Solution Approach 1:
The invention formulates a composite ink system integrating pigment, polymeric dispersing agents with specific functional groups, and non-ionic surfactants. This composite structure provides synergistic effects: the dispersing agent ensures stable pigment suspension and controlled rheology, while the surfactant enhances wetting and adhesion to corrugated board. The formulation achieves high frequency jettability, rapid drying, exceptional stability during continuous recirculation, and high water resistance, meeting all exceptional requirements for in-line printing in corrugated board production
Solution Approach 2:
The patent carefully controls key parameters including pigment concentration (5-40 wt%), polymeric dispersing agent content (0.1-10 wt%), and surfactant concentration. The molecular weight range (10,000-100,000 g/mol) and functional group selection (carboxylic acid, hydroxyl, or amine) are optimized to balance jetting performance, drying speed, and heat abrasion resistance. These parameter optimizations enable the ink to withstand heat exposure during in-line printing while maintaining production flexibility and efficiency
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 inkjet inks exhibit reduced start-up issues, enhanced heat abrasion resistance, and long-term stability, ensuring continuous operation and high image quality in in-line printing applications, while also minimizing VOC emissions and filter clogging.
Implementation Method 1
one or more non-ionic surfactants with a hydrophilic-lipophilic balance (HLB) value of at least 12, wherein the total concentration of non-ionic surfactants with a HLB value of at least 12 in the aqueous pigment concentrate is from 0.1 weight % to 10 weight %
Implementation Method 2
non-ionic surfactants with a hydrophilic-lipophilic balance (HLB) value of at least 12
Data Source
AI summary
The present invention provides an aqueous pigment concentrate comprising one or more pigments, wherein the total pigment concentration in the aqueous pigment concentrate is from 5 to 40 wt. %, one or more pigment dispersing agents, wherein the total pigment dispersing agent concentration in the aqueous pigment concentrate is from 0.5 to 5 wt. %, one or more non-ionic surfactants with a hydrophilic-lipophilic balance (HLB) value of at least (12), wherein the total concentration of non-ionic surfactants with an HLB value of at least (12) in the aqueous pigment concentrate is from 0.1 to 10 wt. %, and water as balance. Also provided is an aqueous ink comprising the aqueous pigment concentrate as well as a use thereof for inkjet printing, preferably on a corrugated board or on a liner for the production of corrugated board.