Photosensitive Resin Composition for Flexographic Printing Plates

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Solution Overview

Problem

Conventional photosensitive resin compositions for flexographic printing plates face challenges with low water solubility, long developing times, reduced image reproducibility, and poor drying properties, particularly when using surfactants to shorten developing times or combining components like water-dispersible latex and photopolymerizable monomers.

Innovation Solution

A photosensitive resin composition comprising water-dispersible latex, a rubber other than a (meth)acrylic modified polymer, a sulfonate surfactant, a photopolymerizable monomer, and a photopolymerization initiator, with specific mass ratios and a dispersed phase size of 10 µm or smaller, along with optional plasticizers, to enhance water developability, drying properties, and image reproducibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If conventional photosensitive resin composition components (water-dispersible latex, photopolymerizable monomer, rubber) are used, then the composition can be formulated, but water developability is insufficient and developing time becomes long

Engineering Contradiction:
Improvedeveloping timeVSAvoidwater developability
Core Design Contradiction:
Loss of timeVSProductivity

Solution Approach 1:

The invention changes the chemical composition parameters by introducing a sulfonate surfactant and specifically controlling the mass ratios of components (A)/(A+B) at 20-90% and (C)/(A+B+C) at 0.1-20%, which fundamentally alters the water developability of the system and reduces developing time

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite photosensitive resin composition integrating water-dispersible latex, rubber, sulfonate surfactant, and photopolymerizable monomer in specific proportions, where the synergistic effect of these components achieves both short developing time and good image reproducibility

Inventive Principle:
Principle #40Composite materials

2Loss of time

If surfactant is added to shorten developing time, then developing time is reduced, but drying time becomes excessively long

Engineering Contradiction:
Improvedeveloping timeVSAvoiddrying time
Core Design Contradiction:
Loss of timeVSDuration of action of moving object

Solution Approach 1:

The invention optimizes the surfactant concentration parameter by limiting (C)/(A+B+C) to 0.1-20%, and controls the overall composition balance to achieve a sweet spot where developing time is shortened without causing excessive drying time

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies sulfonate surfactant locally at controlled concentrations rather than uniformly high concentrations, enabling effective water developability in the development zone while maintaining acceptable drying properties in the final product

Inventive Principle:
Principle #3Local quality

3Loss of time

If surfactant is added to conventional photosensitive resin composition, then developing time is shortened, but image reproducibility deteriorates

Engineering Contradiction:
Improvedeveloping timeVSAvoidimage reproducibility
Core Design Contradiction:
Loss of timeVSManufacturing precision

Solution Approach 1:

The invention changes the chemical environment by using sulfonate surfactant with specific mass ratio constraints, which modifies the development kinetics to achieve both fast development and fine dot reproduction

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention formulates a composite system where sulfonate surfactant works synergistically with water-dispersible latex and photopolymerizable monomer, creating a balanced composition that achieves short developing time while maintaining excellent image reproducibility

Inventive Principle:
Principle #40Composite materials

4Ease of manufacture

If components with low water solubility are used, then the composition can be formulated, but developing process requires long time

Engineering Contradiction:
ImproveformulabilityVSAvoiddeveloping time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The invention fundamentally changes the water solubility parameter of the composition by introducing sulfonate surfactant and optimizing the (A)/(A+B) ratio to 20-90%, transforming the system from low water solubility to high water developability

Inventive Principle:
Principle #35Parameter changes

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 composition achieves excellent water developability, drying properties, and image reproducibility, with improved ink resistance and flexibility, allowing for high-quality flexographic printing with fine structure reproduction.

Implementation Method 1

the photosensitive layer is exposed to ultraviolet rays through a negative film contacted with the photosensitive layer and then uncured portions of the photosensitive layer are removed

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP2551721B1Photosensitive resin composition, printing plate precursor and flexographic printing plate
Publication Date: 2020.07.08 SUMITOMO RIKO CO LTD
  • EP2551721B1 patent drawingFigure 1A~1D
  • EP2551721B1 patent drawingFigure 2A~2C

AI summary

Disclosed is a photosensitive resin composition that provides an excellent water developability, drying property, and image reproducibility. The photosensitive resin composition comprises a water-dispersible latex (A), a rubber (B), a surfactant (C), a photopolymerizable monomer (D), and a photopolymerization initiator (E). A ratio of a mass of the component (C) to a total mass of the components (A), (B), and (C) is within a range of 0.1 to 20%. A ratio of a mass of the component (A) to a total mass of the components (A) and (B) is within 20 to 90%. A size of a dispersed phase consisting mainly of the component (B) is 10 µm or smaller.