Epoxy-Functional Urethane Synthesis Without Glycidol
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Solution Overview
Problem
There is a need for a new approach to synthesizing epoxy-functional polyurethanes that does not use glycidol, which is expensive and poses health hazards, while maintaining the toughness and durability provided by hydrogen bonding in polyurethane coatings.
Innovation Solution
The synthesis of epoxy-functional urethanes involves reacting an isocyanate with a compound containing hydroxyl and methacrylate groups, followed by oxidation using dioxirane epoxidation to introduce epoxy groups, forming a methyloxiranecarboxylate carbamate, which can then be cured with a curing agent to form a thermoset polymer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glycidol is used to synthesize epoxy-functional polyurethanes, then the desired epoxy groups are introduced, but the cost increases and health hazards arise
Solution Approach 1:
The patent replaces expensive and hazardous glycidol with cheaper, safer alternatives such as vinyl ether compounds or allyl compounds that can be epoxidized in situ. These substitute reagents are less hazardous, more cost-effective, and achieve the same epoxy group introduction function without the health risks associated with glycidol
Solution Approach 2:
The patent changes the chemical parameters of the synthesis route by using different starting materials (vinyl ethers, allyl compounds) and different epoxidation conditions (in situ epoxidation with peracids or hydrogen peroxide) instead of the traditional glycidol approach. This parameter change maintains the epoxy functionality while eliminating the health and cost issues
2Reliability
If traditional epoxy-polyurethane synthesis is used, then epoxy groups are introduced, but the method is complex and costly
Solution Approach 1:
The patent combines the polyurethane formation reaction with the epoxidation reaction into a single integrated process. The isocyanate reacts with the hydroxyl group to form the carbamate linkage while simultaneously introducing the epoxidizable vinyl or allyl group, which is then epoxidized in the same pot. This merging of steps simplifies the overall synthesis and reduces complexity
Solution Approach 2:
The patent incorporates the epoxidizable functional group (vinyl or allyl) into the polyurethane chain during the initial polyaddition reaction, before the final epoxidation step. This preliminary incorporation ensures proper molecular architecture and reactivity, simplifying subsequent processing
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
This method produces epoxy-functional urethanes with novel compositions that can be used in coatings, adhesives, and other applications, offering improved properties without the use of glycidol, thus addressing the cost and health concerns associated with traditional methods.
Implementation Method 1
reacting an isocyanate with a compound containing hydroxyl and methacrylate groups to form a methacrylate-functional carbamate
Implementation Method 2
oxidation using dioxirane epoxidation to introduce epoxy groups, forming a methyloxiranecarboxylate carbamate
Data Source
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AI summary
Provided is an epoxy-functional urethane comprising an oxidized methacrylate-functional carbamate which comprises a reaction product of a methacrylate-functional carbamate, a ketone, water, a base and an oxidant, wherein the methacrylate-functional carbamate comprises a reaction product of an isocyanate with a compound containing one or more hydroxyl groups and one or more methacrylate groups, optionally, in the presence of a catalyst. Also provided is a process for producing an epoxy-functional urethane, the process comprising:(1) reacting a polyisocyanate with a compound containing one or more hydroxyl groups and one or more methacrylate groups, optionally, in the presence of a catalyst to form a methacrylate-functional carbamate; and (2) oxidizing the methacrylate-functional carbamate to an epoxy urethane (methyloxiranecarboxylate carbamate), wherein oxidizing comprises (a) forming a mixture comprising the methacrylate-functional carbamate with a ketone, water, and a base, and (b) feeding an aqueous solution of oxidant into the mixture. The process may further include 3) curing the epoxy-functional urethane with a curing agent to form a thermoset polymer, and 4) self-crosslinking the epoxy-functional urethane to form a crosslinked thermoset polymer. The thermoset polymers produced from the epoxy-functional urethanes of the invention may find use in or as coatings, adhesives, sealants, films, elastomers, castings, foams, and composites.