Photosensitive Resin Composition for Flexographic Plates

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Solution Overview

Problem

Flexographic printing plates face issues with fine line reproducibility, ester solvent resistance, and surface cracking due to existing photosensitive resin compositions, which affect the quality and durability of printed images.

Innovation Solution

A photosensitive resin composition comprising a thermoplastic elastomer with vinyl aromatic hydrocarbon, butadiene, and alkylene units, where alkylene units range from 5 to 80 wt% of the total, providing improved fine line reproducibility, ester solvent resistance, and reduced surface cracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a styrene-isoprene block copolymer is used as a polymer in a photosensitive resin, then resistance to ester solvents is improved, but cracks occur on plate surface and abrasion resistance is insufficient

Engineering Contradiction:
Improveester solvent resistanceVSAvoidsurface crack resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent changes the chemical composition parameters of the polymer by specifying a styrene content of 10-40 wt% and incorporating specific diene units (1,2-bond units) content of 1-70 wt%, creating a balanced polymer structure that simultaneously achieves ester solvent resistance and surface crack prevention

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite polymer structure combining styrene units, diene units with specific 1,2-bond configurations, and alkylene units in defined proportions, creating a multi-component polymer system that delivers both chemical resistance and mechanical durability

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If a terpolymer having randomly distributed ethylene, propylene, and diene units is used as a polymer in a photosensitive resin, then processing is facilitated, but fine line reproducibility is insufficient

Engineering Contradiction:
Improveprocessing easeVSAvoidfine line reproducibility
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent optimizes the polymer's molecular parameters by controlling styrene content (10-40 wt%) and diene unit composition (1,2-bond units 1-70 wt%), achieving a balance between processability and fine line reproduction capability

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If a block copolymer having a styrene block, an alkylene block, and an isoprene block is used as a polymer in a photosensitive resin, then elasticity is improved, but fine line reproducibility, chipping resistance, and prevention of cracks occurring on plate surface are insufficient

Engineering Contradiction:
ImproveelasticityVSAvoidfine line reproducibility
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent modifies the block copolymer structure by precisely controlling the composition ratios: styrene (10-40 wt%), diene units with 1,2-bond (1-70 wt%), and alkylene units (5-80 wt%), optimizing both elastic properties and fine line reproduction

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite polymer structure integrating multiple functional units (styrene, diene, alkylene) in specific proportions, where each component contributes different properties that collectively achieve elasticity, fine line reproducibility, and crack resistance

Inventive Principle:
Principle #40Composite materials

4Reliability

If the alkylene units content in a thermoplastic elastomer is increased to improve ester solvent resistance, then chipping resistance decreases

Engineering Contradiction:
Improveester solvent resistanceVSAvoidchipping resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent optimizes the alkylene units content within a specific range (5-80 wt%) rather than maximizing it, balancing ester solvent resistance with chipping resistance by preventing excessive alkylene content that would compromise mechanical strength

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 high fine line reproducibility, enhanced ester solvent resistance, and prevents surface cracking, ensuring better printing quality and durability of flexographic printing plates.

Implementation Method 1

a photopolymerization initiator (c)... subjecting the surface of a photosensitive resin layer to relief exposure through a negative film... and conducing post-exposure

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS7785765B2Photosensitive resin composition
Publication Date: 2010.08.31 ASAHI KASEI CHEM CORP

AI summary

The present invention relates to a photosensitive resin composition comprising at least a thermoplastic elastomer (a), a photopolymerizable unsaturated monomer (b), and a photopolymerization initiator (c), characterized in that the thermoplastic elastomer (a) comprises at least vinyl aromatic hydrocarbon units, butadiene units, and alkylene units and contains alkylene units not less than 5 wt % and not more than 80 wt % with respect to the total amount of butadiene units and alkylene units. The present invention provides a photosensitive resin composition that simultaneously achieves excellent fine line reproducibility, ester solvent resistance, and prevention of cracks occurring on plate surface.