Fluorene-Based Photopolymerization Initiator for High Sensitivity

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Solution Overview

Problem

Conventional photopolymerization initiators, such as those with a carbazole skeleton, have limitations in sensitivity to active energy rays and solubility, necessitating the development of a compound with improved characteristics for various applications.

Innovation Solution

A novel fluorene-based compound with specific substitutions at the 2- and 7-positions, which serves as a photopolymerization initiator, enhancing sensitivity and solubility when incorporated into a photosensitive composition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional photopolymerization initiators with carbazole skeleton are used, then sensitivity to active energy ray is achieved, but solubility is insufficient

Engineering Contradiction:
Improvesensitivity to active energy rayVSAvoidsolubility
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the chemical structure parameters by replacing the carbazole skeleton with a fluorene skeleton and introducing specific substituents (oxime ester groups at positions 2 and 7, and alkyl groups at position 9) to simultaneously achieve high sensitivity and improved solubility

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite molecular structure combining fluorene core with oxime ester functional groups and alkyl substituents, achieving synergistic effects that improve both sensitivity and solubility properties

Inventive Principle:
Principle #40Composite materials

2Reliability

If photopolymerization initiator with high sensitivity is developed, then sensitivity to active energy ray is improved, but performance for various applications may be compromised

Engineering Contradiction:
Improvesensitivity to active energy rayVSAvoidperformance for various applications
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The fluorene-based compound is designed to perform multiple functions: it acts as a photopolymerization initiator with high sensitivity, provides good solubility in various solvents, and maintains stability across different application conditions, making it universally applicable

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If new fluorene-based compound is synthesized, then sensitivity and solubility are improved, but synthesis complexity increases

Engineering Contradiction:
Improvesensitivity to active energy rayVSAvoidsynthesis complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The synthesis is divided into distinct segments: first forming the fluorene core with alkyl groups, then introducing oxime ester groups at specific positions, allowing for systematic and manageable synthesis steps

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces functional groups at specific local positions (oxime ester at positions 2 and 7, alkyl at position 9) to achieve desired properties without complicating the entire molecular structure

Inventive Principle:
Principle #3Local quality

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 fluorene-based compound exhibits high sensitivity to active energy rays and improved solubility, making it suitable for diverse applications beyond conventional initiators.

Implementation Method 1

a photosensitive composition containing a compound having an ethylenically unsaturated bond and a photopolymerization initiator can be cured by being irradiated with an active energy ray

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP2913323B1Fluorene-type compound, photopolymerization initiator comprising said fluorene-type compound, and photosensitive composition containing said photopolymerization initiator
Publication Date: 2018.09.12 TOKYO OHKA KOGYO CO LTD
  • EP2913323B1 patent drawingFigure 1(A)~1(B)
  • EP2913323B1 patent drawingFigure 2
  • EP2913323B1 patent drawingFigure 3

AI summary

According to an embodiment of the present invention, there is provided a novel fluorene-based compound and a photopolymerization initiator using the fluorene-based compound. The fluorene-based compound according to an embodiment of the present invention is represented by the general formula (1). A photopolymerization initiator having additionally high sensitivity can be provided by using the fluorene-based compound. In addition, a photopolymerization initiator that can impart additionally excellent characteristics can be provided by appropriately selecting, for example, a substituent.