Novel Thiol Compounds for Epoxy Adhesives

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Solution Overview

Problem

Conventional thiol compounds used in epoxy resin compositions have ester bonds that decompose under humid conditions, leading to poor moisture resistance in cured products.

Innovation Solution

Development of new thiol compounds with specific structures, represented by chemical formulas (I) to (VII), which are synthesized through reactions involving carbonyl compounds, dialkene compounds, and thiol compounds, excluding ester bonds to enhance hydrolysis resistance and compatibility with epoxy and enic compounds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional thiol compounds with ester bonds are used as curing agents, then the curing reaction proceeds well, but the cured product shows poor moisture resistance due to hydrolysis of ester bonds

Engineering Contradiction:
Improvemoisture resistanceVSAvoidhydrolysis reaction
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention extracts and removes the ester bond structure from the thiol compound molecule. By designing thiol compounds without ester bonds (using formulas I-VII instead of conventional ester-containing structures), the source of hydrolysis is eliminated while maintaining the curing agent functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the chemical structure parameters of the thiol compound by defining specific molecular formulas (I-VII) with controlled alkylene groups (m=1-5, n=1-5) and substituent groups (R1, R2, R3), thereby altering the chemical stability against hydrolysis while preserving reactivity with epoxy compounds.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If thiol compounds are designed for high reactivity with epoxy compounds, then curing efficiency improves, but compatibility and elasticity of the cured product may be compromised

Engineering Contradiction:
Improvecuring efficiencyVSAvoidcompatibility and elasticity
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The invention applies local quality by differentiating the functional regions of the thiol compound: the thiol group (-SH) provides high reactivity for curing efficiency, while the alkylene chain structure (with controllable length m and n) and substituent groups (R1, R2, R3) provide compatibility and elasticity. This spatial separation of functions resolves the contradiction.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The thiol compound structure combines multiple functional elements (thiol groups, alkylene chains, and variable substituent groups) into a composite molecular structure that simultaneously achieves reactivity, compatibility, and elasticity through the synergistic arrangement of its components.

Inventive Principle:
Principle #40Composite materials

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 new thiol compounds provide cured products with improved hydrolysis resistance and moisture resistance, making them suitable for use in adhesives and sealants with low elasticity and excellent compatibility.

Implementation Method 1

reacting a carbonyl compound represented by the chemical formula (1) with a thiol compound represented by the chemical formula (2)

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

reacting a dialkene compound selected from vinylcyclohexene, limonene, tetrahydroindene, and dicyclopentadiene with a thiol compound represented by the chemical formula (3)

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 3

the ester bond is decomposed by hydrolysis reaction under humidification conditions

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentEP3998252B1Thiol compounds, synthesis method therefor, and utilization of said thiol compounds
Publication Date: 2024.04.24 SHIKOKU CHEM CORP
  • EP3998252B1 patent drawingFigure 1
  • EP3998252B1 patent drawingFigure 2
  • EP3998252B1 patent drawingFigure 3

AI summary

The purpose of the present invention is to provide: novel thiol compounds; a method for synthesizing said thiol compounds; curing agents containing said thiol compounds; resin compositions containing said thiol compounds and an epoxy compound; and resin compositions containing said thiol compounds and an ene compound having a carbon-carbon double bond in a molecule. Furthermore, the purpose of the present invention is to provide adhesives and sealants having these resin compositions as ingredients. The thiol compounds of the present invention are represented by chemical formula (II) to chemical formula (IV).