Thiol-Containing Epoxy Composition for Extended Workability and Bonding
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Solution Overview
Problem
Existing coating and adhesive compositions face challenges in achieving optimal balance of properties such as elongation, load-bearing strength, and resistance to environmental conditions, while maintaining workability and ease of application.
Innovation Solution
A composition comprising an epoxy-containing compound, a polythiol curing agent, and a second curing agent, with specific equivalent weight ratios and filler package pH, to create a 1K system that remains workable for extended periods before curing, allowing for improved adhesion and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high cross-link density is achieved through epoxy-polythiol curing, then load-bearing strength and durability are improved, but elongation and workability deteriorate
Solution Approach 1:
The curing system is segmented into two distinct components: a polythiol curing agent and a second curing agent (amine or anhydride). The polythiol provides initial cross-linking for strength, while the second curing agent completes the cure and enhances elongation. This segmentation allows each component to contribute specific properties without compromising the other.
Solution Approach 2:
The patent optimizes the equivalent weight parameters of the polythiol curing agent (40-600 g/eq) and the epoxy-containing compound (50-2000 g/eq) to control the cross-link density and network structure. By adjusting these parameters, the composition achieves a balance between cross-link density (for strength) and network flexibility (for elongation and workability).
2Ease of operation
If extended workability is achieved by reducing cross-link density, then elongation and ease of application are improved, but load-bearing strength deteriorates
Solution Approach 1:
The polythiol curing agent performs preliminary cross-linking action that establishes the basic network structure and provides initial strength. This preliminary action allows the composition to maintain workability during application while already having sufficient cross-links to prevent complete gelation, enabling extended pot life without sacrificing ultimate strength.
Solution Approach 2:
The composition creates a composite curing network combining two different curing mechanisms: sulfur-based cross-linking from the polythiol and nitrogen- or oxygen-based cross-linking from the second curing agent. This composite structure provides both the flexibility needed for workability and the density required for load-bearing strength.
3Strength
If optimal adhesion is achieved through specific equivalent weight ratios, then bonding strength is improved, but composition complexity increases
Solution Approach 1:
The patent establishes specific equivalent weight ratio ranges (epoxy:polythiol from 1:5 to 5:1) that optimize the cross-linking stoichiometry for maximum adhesion. By defining these parameter ranges, the patent simplifies composition design while achieving optimal bonding strength through controlled chemical stoichiometry.
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 composition achieves enhanced elongation, load-bearing strength, and resistance to environmental factors, with a 1K system that maintains workability and cures effectively upon activation, providing improved bonding and sealing properties.
Implementation Method 1
an epoxy-containing compound; a polythiol curing agent
Implementation Method 2
a composition comprising: an epoxy-containing compound; a polythiol curing agent; and a second curing agent
Data Source
AI summary
The present invention is directed toward a composition comprising: an epoxy compound, a polythiol curing agent, and a second curing agent. Also disclosed are methods of treating a substrate with the composition and substrates formed by such methods.