Polythiol Carbamate Compositions for Adhesive Cure
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Solution Overview
Problem
Current polythiol compositions used in adhesives and coatings lack optimal reactivity, cure time, weatherability, and toughness, particularly in comparison to amine curing technologies.
Innovation Solution
Development of polythiol compositions containing sulfur-containing compounds with carbamate groups, formed by reacting compounds with specific molecular structures and H2S, along with optional phosphite compounds, to create sulfur-containing compounds with multiple carbamate and thiol groups, enhancing reactivity and molecular weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional polythiol compositions are used in adhesives and coatings, then the formulations can be produced with existing methods, but the reactivity is insufficient and cure times are prolonged
Solution Approach 1:
The patent modifies the chemical structure of polythiol compounds by incorporating carbamate groups and multiple thiol groups per molecule. This structural parameter change increases the functionality and reactivity of the curing agent, enabling faster cure times while maintaining complete crosslinking of epoxy resins. The specific structural modification transforms conventional polythiols into more reactive compounds without requiring changes to existing formulation procedures.
2Productivity
If polythiol compositions with higher reactivity are developed, then cure times can be reduced, but the complexity of synthesis processes increases
Solution Approach 1:
The synthesis process is divided into two distinct stages: first, forming a polycarbamate intermediate by reacting a polyol with an isocyanate; second, converting the polycarbamate to the final polythiol product by reaction with hydrogen sulfide. This segmentation allows each stage to be optimized independently and simplifies process control while achieving the desired high reactivity product.
Solution Approach 2:
The patent introduces a polycarbamate compound as an intermediate species in the synthesis pathway. This intermediate serves as a bridge between the starting materials (polyol and isocyanate) and the final high-reactivity polythiol product. The intermediary approach enables controlled formation of the complex molecular structure with multiple carbamate and thiol groups.
3Reliability
If conventional polythiol formulations are used, then the manufacturing process is simple, but the weatherability and toughness of the final product are insufficient
Solution Approach 1:
The patent creates a composite molecular structure within the polythiol curing agent by combining multiple functional groups (carbamate groups and thiol groups) in a single molecule. This composite structure provides both the desired performance properties (enhanced weatherability and toughness) and maintains compatibility with existing epoxy resin formulations. The multi-functional molecular design achieves superior material properties without complicating the overall manufacturing approach.
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 resulting polythiol compositions exhibit improved reactivity, faster cure times, enhanced weatherability, and increased toughness, while reducing process steps and waste, compared to traditional methods.
Implementation Method 1
contacting the polycarbamate, H2S, and an optional phosphite compound to form the polythiol composition
Data Source
AI summary
The present invention discloses polythiol compositions containing sulfur-containing compounds with carbamate groups, and to methods for producing such polythiol compositions. These polythiol compositions can be synthesized via the reaction of an isocyanate with an allyl ether alcohol, followed by thiolation with H2S, and these polythiol compositions are often used in formulations for adhesives, paints, and coatings.