Lithographic Printing Plate Precursor Chemical Resistance
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Solution Overview
Problem
Existing positive type lithographic printing plates face challenges in achieving excellent chemical resistance and printing durability without performing a burning treatment, especially when using binder resins like urea or urethane polymers that have low chemical resistance.
Innovation Solution
A lithographic printing plate precursor with a hydrophilic support, an underlayer containing a polymer compound with urethane or acetal structures, an interlayer with sulfonamide or active imide groups, and an upper layer with phenolic hydroxy groups, where one or more layers include an infrared absorbent, allowing for improved chemical resistance and durability without burning treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a burning treatment is performed to improve printing durability, then printing durability is improved, but chemical resistance is degraded due to polymer decomposition
Solution Approach 1:
The invention changes the chemical composition parameters of the binder resin by introducing specific functional groups (sulfonamide groups, active imide groups, urea bonds) that fundamentally alter the material's thermal stability and chemical resistance properties, allowing high printing durability without burning treatment
Solution Approach 2:
The invention creates a composite binder resin system combining multiple polymer components with complementary functions: polyvinyl acetal provides base adhesion, while copolymers containing sulfonamide and active imide groups provide thermal stability and chemical resistance, achieving synergistic effects that eliminate the need for burning treatment
2Stability of the object's composition
If a polymer compound with high chemical resistance is used, then chemical resistance is improved, but printing durability is degraded
Solution Approach 1:
The invention adjusts the chemical composition parameters by controlling the types and ratios of functional groups (sulfonamide, active imide, urea) in the binder resin, achieving an optimal balance where chemical resistance and printing durability are simultaneously improved through specific molecular structure design
3Measurement precision
If the amount of infrared absorbent is increased to improve image forming sensitivity, then image forming sensitivity is improved, but ablation occurs causing contamination of the exposure machine
Solution Approach 1:
The invention changes the thermal parameters of the binder resin by introducing sulfonamide and active imide groups that raise the decomposition temperature and improve thermal stability, allowing higher infrared absorbent content to be used without causing ablation, thus improving image forming sensitivity without contamination
Solution Approach 2:
The invention converts the potential harmful effect of heat generation from infrared absorbent into a beneficial effect by using the heat to trigger controlled development while the thermally stable binder resin prevents harmful ablation, turning a previously problematic parameter into an advantage
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 configuration enhances chemical resistance and printing durability of the lithographic printing plate, improving image formability and resistance to UV ink and oil-based inks without the need for high-temperature treatments.
Implementation Method 1
an infrared absorbent (for example, an infrared absorbing dye (IR dye)) which absorb light and generate heat
Implementation Method 2
in the exposed portion (non-image area), the interaction between the IR dye and the binder resin weakens due to generated heat
Data Source
AI summary
Provided is a positive type lithographic printing plate precursor including at least: a support which has a hydrophilic surface or a hydrophilic layer; and an underlayer, an interlayer, and an upper layer on the support in this order, in which the underlayer contains a polymer compound 1 which has at least one structure selected from the group consisting of a urethane bond, an acetal structure, and a urea bond in a main chain, the interlayer contains a polymer compound 2 which has at least one structure selected from the group consisting of a sulfonamide group, an active imide group, and a urea bond in a side chain, the upper layer contains a polymer compound 3 which has a phenolic hydroxy group, and one or more layers among the underlayer, the interlayer, and the upper layer contain an infrared absorbent. Further, provided are a method of producing the positive type lithographic printing plate precursor and a method of preparing a lithographic printing plate using the positive type lithographic printing plate precursor.