Planographic Printing Ink pH Control for Scumming Resistance
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Solution Overview
Problem
Conventional active energy ray-curable inks in planography suffer from insufficient cohesiveness, leading to excessive emulsification and printing failures such as scumming due to their low molecular weight resins and high hydrophilicity, which narrows the suitable range for dampening water supply.
Innovation Solution
A method involving a planographic printing process where the pH of the ink and dampening water are both maintained between 1 to 6.5, with the ink containing a resin having an acidic group to enhance cohesiveness and resist excessive emulsification, allowing for improved ink adhesion and scumming resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If active energy ray-curable planographic inks are used to reduce volatile compounds and shorten drying time, then environmental performance and productivity are improved, but the ink cohesiveness becomes insufficient leading to excessive emulsification
Solution Approach 1:
The patent changes the pH parameter of both the ink and dampening water to the acidic range (1-6.5), which fundamentally alters the emulsification behavior. This parameter change suppresses excessive emulsification while maintaining the benefits of active energy ray-curable inks, resolving the contradiction between productivity improvement and ink stability
Solution Approach 2:
The patent uses composite ink formulations containing resins with acidic groups combined with specific (meth)acrylate compounds. This composite approach creates an ink system that maintains cohesiveness through acidic resin interactions while preserving the curability and productivity benefits of (meth)acrylate-based formulations
2Quantity of substance
If the amount of dampening water is increased to improve emulsification, then ink incorporation is enhanced, but excessive emulsification occurs causing scumming in non-image areas
Solution Approach 1:
By changing the pH parameter to acidic conditions (1-6.5), the patent expands the suitable range of dampening water supply. The acidic environment suppresses excessive emulsification even when larger amounts of dampening water are used, allowing improved ink incorporation without sacrificing printing quality and preventing scumming
3Ease of manufacture
If resins with lower molecular weights and higher polarities are used in active energy ray-curable inks, then curability is improved, but ink cohesiveness decreases leading to excessive emulsification
Solution Approach 1:
The patent creates a composite ink system combining resins with acidic groups and (meth)acrylate compounds. The acidic resin provides cohesiveness through hydrogen bonding and acid-base interactions, while the (meth)acrylate components ensure curability. This composite formulation resolves the contradiction between ease of manufacture (curability) and composition stability (cohesiveness)
Solution Approach 2:
The patent changes the chemical parameter of the resin system by introducing acidic groups, which fundamentally alters the intermolecular interactions. The acidic groups provide strong hydrogen bonding and acid-base interactions that enhance cohesiveness, allowing the use of lower molecular weight and higher polarity components while maintaining ink 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
This method effectively suppresses excessive emulsification, achieving excellent scumming resistance and printing quality by ensuring the ink adheres correctly to the heat-sensitive layer while maintaining ink solubility in basic wash solutions for easy removal.
Implementation Method 1
impart sufficient cohesiveness to an ink
Implementation Method 2
excessive emulsification is likely to occur
Implementation Method 3
maintaining ink solubility in basic wash solutions for easy removal
Implementation Method 4
ensuring the ink adheres correctly to the heat-sensitive layer
Data Source
AI summary
The present invention aims to provide a method of producing a printed matter that shows suppressed scumming in planography. A method of producing a printed matter, the method including the steps of: allowing a dampening water to adhere to a hydrophilic layer of a planographic printing plate having at least the hydrophilic layer and a heat sensitive layer; allowing an ink to adhere to the heat sensitive layer; and transferring the ink adhering to the heat sensitive layer to an object to be printed; wherein the pH (A) of the ink and the pH (B) of the dampening water are both from 1 to 6.5.