Sulfonium Salt Photoacid Generator for UV Curing
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Solution Overview
Problem
Existing photoacid generators have low sensitivity to g-rays and h-rays, and also exhibit low solubility, limiting their use in curing cationically polymerizable compounds.
Innovation Solution
A novel sulfonium salt with enhanced photosensitivity to g-rays and h-rays is synthesized, which is used to formulate a photoacid generator that demonstrates high compatibility with cationically polymerizable compounds and excellent storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sulfonium salts are used as photoacid generators, then they can cure cationically polymerizable compounds, but they have low sensitivity to g-rays and h-rays requiring addition of sensitizers
Solution Approach 1:
The patent modifies the molecular structure of sulfonium salts by changing parameters such as introducing specific substituent groups (e.g., fluorinated groups, aromatic hydrocarbon groups) and adjusting the ratio of cationic to anionic components. These parameter changes enhance the photosensitivity to g-rays and h-rays while maintaining curing ability, eliminating the need for sensitizers.
Solution Approach 2:
The patent creates composite photoacid generator systems by combining sulfonium salts with specific anions (e.g., fluorinated sulfonates, tetrafluoroborate) in optimized ratios. This composite approach synergistically improves both the photosensitivity to short-wavelength UV light and the curing performance on cationically polymerizable compounds.
2Ease of manufacture
If conventional photoacid generators are used, then they can be formulated into compositions, but they exhibit low solubility limiting their use
Solution Approach 1:
The patent introduces solubility-enhancing parameters into the sulfonium salt structure, such as adding alkoxy groups, fluorinated chains, or bulky aromatic groups. These structural modifications increase the solubility in common solvents and resins while preserving the photoacid generation function and curing ability.
3Productivity
If sensitizers are added to improve photosensitivity, then sensitivity to g-rays and h-rays increases, but the composition complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the need for sensitizer additives by incorporating the photosensitivity-enhancing functional groups directly into the sulfonium salt molecule itself. This integration removes the separate sensitizer component, simplifying the composition while maintaining high sensitivity to g-rays and h-rays.
4Productivity
If existing sulfonium salts are used to enhance sensitivity, then photosensitivity improves, but solubility remains low
Solution Approach 1:
The patent applies local quality modification by introducing specific functional groups at particular positions on the sulfonium salt molecule. For example, adding solubility-enhancing groups to specific rings or positions while maintaining the core photosensitive structure, achieving both high sensitivity and good solubility through localized structural optimization.
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 photoacid generator exhibits excellent curing ability under ultraviolet light, particularly for g-rays and h-rays, without the need for sensitizers, resulting in cost-effective and high-quality cured products with improved pattern formation and storage stability.
Implementation Method 1
Photoacid generator is a general term for compounds which are decomposed when exposed to active energy rays, such as light, electron beam, or X-rays, thereby generating acids
Implementation Method 2
The acids generated by exposure to active energy rays are used as active species in various reactions including polymerization, crosslinking, and deprotection
Data Source
AI summary
Provided are a novel sulfonium salt having high photosensitivity to g-rays or h-rays; a novel photoacid generator containing a sulfonium salt that has high photosensitivity to g-rays or h-rays, has high solubility in solvents and cationically polymerizable compounds such as epoxy compounds, and has an excellent storage stability in compositions containing the cationically polymerizable compounds; and the like. The present invention relates to a sulfonium salt represented by the formula (1), a photoacid generator containing the sulfonium salt, and the like.