Oxime Ester Photopolymerization Initiator for Low Sublimation

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Solution Overview

Problem

Current oxime ester compounds used as photopolymerization initiators in photosensitive compositions lack satisfactory sensitivity, leading to poor developability and contamination issues due to high concentrations required for high sensitivity, especially in colored alkali-developable photosensitive resin compositions.

Innovation Solution

A novel oxime ester compound represented by a specific general formula, which is stable, has low sublimability, and efficiently absorbs near-ultraviolet light, serving as a high-sensitivity photopolymerization initiator, along with a photosensitive composition containing this compound and a polymerizable compound with ethylenically unsaturated bonds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the concentration of photopolymerization initiator is increased to improve sensitivity, then sensitivity is improved, but developability deteriorates causing scum formation and contamination

Engineering Contradiction:

ImprovesensitivityVSAvoidscum formation and contamination

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention changes the chemical structure parameters of the photopolymerization initiator by introducing specific substituents (R1-R6 groups) at defined positions in the molecular structure. This structural modification alters the compound's physical and chemical properties, enabling high sensitivity at low concentrations while maintaining good developability and reducing contamination issues.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The photopolymerization initiator is designed as a composite molecular structure combining multiple functional groups (oxime ester core with various substituent groups R1-R6). This composite structure integrates the benefits of different molecular components, achieving both high photoreactivity for sensitivity and appropriate volatility control for clean development.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If conventional oxime ester compounds are used, then ease of manufacture is maintained, but sensitivity is insufficient requiring high concentration

Engineering Contradiction:

Improveease of manufactureVSAvoidsensitivity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention modifies the conventional oxime ester structure by changing specific parameters: introducing electron-withdrawing or electron-donating groups (R1-R6) at strategic positions, adjusting the core structure, and optimizing molecular weight. These parameter changes enhance light absorption efficiency and radical generation capability, improving sensitivity while keeping the synthesis route relatively straightforward.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If high concentration of photopolymerization initiator is used to achieve high sensitivity, then sensitivity is improved, but sublimation increases causing contamination

Engineering Contradiction:

ImprovesensitivityVSAvoidsublimation and contamination

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The molecular structure is optimized by adjusting parameters such as molecular weight, intermolecular interaction strength, and volatility characteristics through substituent selection (R1-R6 groups). This enables the initiator to maintain high photoreactivity at low concentrations while having sufficiently low vapor pressure to minimize sublimation and contamination during processing.

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 novel oxime ester compound provides improved sensitivity and stability, reducing sublimation issues and contamination, while maintaining high sensitivity and efficiency in photopolymerization, particularly suitable for colored alkali-developable photosensitive resin compositions.

Implementation Method 1

A photosensitive composition contains a polymerizable compound having an ethylenically unsaturated bond and a photopolymerization initiator. A photosensitive composition polymerizes to cure on being irradiated with energy rays (light)

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

efficiently absorbs, and is activated by, near-ultraviolet light, e.g., at 365 nm

Methodology Applied

Scientific EffectAbsorption of electromagnetic radiation: Absorption (EM radiation)

Data Source

PatentEP3127898B1Oxime ester compound and photopolymerization initiator containing said compound

Publication Date: 2021.08.25 ADEKA CORP

AI summary

An oxime ester compound represented by general formula (I), wherein R1 to R8 are as defined in the description, and n is 0 or 1; a photopolymerization initiator containing the compound; a photosensitive composition, alkali-developable photosensitive resin composition, and colored alkali-developable photosensitive resin composition containing the photopolymerization initiator; and a cured product of these compositions are provided. The compound is useful as a high-sensitivity photopolymerization initiator that has good stability and low sublimability and that efficiently absorbs, and is activated by, near-ultraviolet light, e.g., at 365 nm.