Oxime Ester Photopolymerization Initiators for 365 nm and 405 nm Absorption

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Solution Overview

Problem

Conventional oxime ester-based photopolymerization initiators lack high absorption at 365 nm and 405 nm wavelengths, resulting in unsatisfactory sensitivity for short-wavelength light sources used in photopolymerization processes.

Innovation Solution

Development of novel oxime ester compounds represented by general formula (I), which are used as photopolymerization initiators in photosensitive resin compositions, providing enhanced photoabsorption and sensitivity at 365 nm and 405 nm wavelengths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional oxime ester-based photopolymerization initiators are used, then the photopolymerization process can proceed, but the absorption at 365 nm and 405 nm wavelengths is insufficient resulting in low sensitivity

Engineering Contradiction:

Improvephotoabsorption at 365 nm and 405 nmVSAvoidsensitivity

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent modifies the molecular structure of oxime ester compounds by changing parameters such as the aromatic group (Ar) substituents and positions, and the acyl group structure. These parameter changes in the chemical structure result in enhanced photoabsorption at 365 nm and 405 nm wavelengths while maintaining photopolymerization initiator functionality.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates new composite oxime ester compounds combining specific aromatic groups, acyl groups, and oxime ester functional groups. This composite molecular structure achieves both high photoabsorption at target wavelengths and satisfactory sensitivity for photopolymerization initiation.

Inventive Principle:

Principle #40Composite materials

2Reliability

If photopolymerization initiators with higher sensitivity are developed, then the sensitivity improves, but the structural complexity increases

Engineering Contradiction:

ImprovesensitivityVSAvoidmolecular structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces specific local structural features into the oxime ester molecules, such as particular aromatic substituents (methyl, ethyl, halogen atoms) at defined positions, and specific acyl group structures. These localized structural modifications enhance sensitivity without requiring complete redesign of the entire molecular structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention systematically varies molecular parameters including the type of aromatic group, position of substituents, and acyl group structure to optimize sensitivity. This parameter-based approach allows controlled enhancement of performance while managing structural complexity.

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 compounds exhibit excellent photosensitivity, resolution, and stability, making them suitable for photopolymerization processes with i-beam light sources, and are useful in various applications such as photocuring inks and printing plates.

Implementation Method 1

the oxime ester compounds of the invention have excellent photosensitivity, resolution and stability over time, and particularly the absorbance at 365 nm and 405 nm is higher than hitherto possible

Methodology Applied

Scientific EffectPhotoabsorption: Absorption (EM radiation)

Implementation Method 2

ultraviolet irradiation resulting in production of active radicals by the photopolymerization initiator, which reacts with the ethylenic unsaturated compound for polymerization

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS8088836B2Oxime ester compounds and photosensitive resin compositions using the same

Publication Date: 2012.01.03 NIPPON CHEM WORKS

AI summary

An oxime ester compound represented by the following general formula (I):(the symbols of which are defined in the specification)is used as the photopolymerization initiator in a photosensitive resin composition.