Isocyanate-Free Polyurethane Synthesis via Cyclic Monothiocarbonates
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Solution Overview
Problem
The existing methods for manufacturing polyurethanes rely on compounds with isocyanate groups, which are highly reactive, moisture-sensitive, and potentially harmful, leading to issues in technical applications and requiring the development of alternative processes that avoid these compounds while maintaining mechanical and optical properties.
Innovation Solution
A process involving compounds with five-membered cyclic monothiocarbonate groups and amino groups is used to form polymers with urethane groups, avoiding isocyanate groups and minimizing by-products like water or alcohol, with the option to incorporate functional groups for easy modification or crosslinking, using a method that includes reacting epoxy compounds with phosgene or alkyl chloroformate and anionic sulfur to form monothiocarbonate groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If compounds with isocyanate groups are used to manufacture polyurethanes, then the mechanical properties and reactivity are improved, but the moisture sensitivity and harmful effects increase
Solution Approach 1:
The invention extracts and eliminates the harmful isocyanate groups from the polyurethane synthesis process while retaining the desired mechanical properties. This is achieved by using alternative compounds (cyclic monothiocarbonates and amino compounds) that do not contain isocyanate groups but can still form polyurethane polymers through a different reaction pathway, thereby removing the source of moisture sensitivity and harmful effects.
Solution Approach 2:
The invention changes the chemical parameters of the starting materials by replacing isocyanate-containing compounds with cyclic monothiocarbonate and amino compound combinations. This parameter change alters the reaction mechanism and intermediates, eliminating the formation of harmful by-products while maintaining the final polyurethane structure and mechanical properties.
2Ease of manufacture
If traditional polyurethane synthesis using isocyanates is employed, then the manufacturing process is straightforward, but the production of harmful by-products and condensation products increases
Solution Approach 1:
The invention converts the potentially harmful reaction pathway into a beneficial one by using cyclic monothiocarbonates and amino compounds that react to form polyurethanes without generating harmful condensation by-products. The reaction produces water as the only by-product, which is significantly less harmful than the isocyanate-containing by-products of traditional methods, thus turning a potentially harmful process into a clean manufacturing method.
3Speed
If compounds with isocyanate groups are used, then the reactivity and polymerization speed are improved, but the safety and environmental compatibility deteriorate
Solution Approach 1:
The invention introduces cyclic monothiocarbonates as intermediary compounds that react with amino compounds to form polyurethanes. These intermediaries provide a safe and environmentally compatible reaction pathway that maintains adequate polymerization speed while eliminating the safety and environmental issues associated with direct isocyanate use. The intermediary compounds are less hazardous and produce cleaner reaction products.
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 process allows for the production of polymers with improved mechanical and optical properties, reduced moisture sensitivity, and the ability to modify or crosslink easily, providing a safer and more effective alternative to traditional polyurethane synthesis.
Implementation Method 1
a compound A) with at least two five-membered cyclic monothiocarbonate groups and a compound B) with at least two amino groups, selected from primary or secondary amino groups are reacted
Implementation Method 2
a compound C) with at least one functional group that reacts with a group —SH
Data Source
AI summary
Process for the manufacturing of a polymer with urethane groups, wherein in a first alternative a compound A) with at least two five-membered cyclic monothiocarbonate groups and a compound B) with at least two amino groups, selected from primary or secondary amino groups and optionally a compound C) with at least one functional group that reacts with a group —SH are reacted or wherein in a second alternative a compound A) with at least two five-membered cyclic monothiocarbonate groups or a mixture of a compound A) with a compound A1) with one five-membered cyclic monothiocarbonate group and a compound B) with at least two amino groups, selected from primary or secondary amino groups or a compound B1) with one amino group selected from primary or secondary amino groups or mixtures of compounds B) and B1) and a compound C) with at least two functional groups that react with a group —SH or in case of a carbon-carbon triple bond as functional group that react with a group —SH, a compound C) with at least one carbon-carbon triple bond. are reacted.