Silyl-Modified Polyurethane via Cyclic Monothiocarbonate Ring Opening
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Solution Overview
Problem
There is a demand for alternative polymers with urethane groups and moisture-curable silyl groups that include additional heteroatoms or functionalities to enhance technical applications, and for new processes to prepare silyl-modified polyurethanes that do not involve the use of isocyanates.
Innovation Solution
A process involving compounds with a five-membered cyclic monothiocarbonate group and amino groups, optionally with silicon-functional groups, is used to create cross-linked polymers with urethane and thioether groups, which are cured using ambient water, allowing for the production of silyl-modified polymers suitable for various technical applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If isocyanates are used to prepare silyl-modified polyurethanes, then the mechanical properties and moisture curability are achieved, but the process complexity and safety concerns increase
Solution Approach 1:
The patent extracts and removes isocyanates from the polymerization process, replacing them with cyclic monothiocarbonate compounds that react with amino groups to form urethane linkages. This eliminates the need for hazardous isocyanate handling while maintaining the desired polyurethane properties and moisture curability through silicon-functional groups.
Solution Approach 2:
The invention changes the chemical parameters of the starting materials from isocyanate-based to cyclic monothiocarbonate-based compounds. This parameter change fundamentally alters the reaction pathway, enabling urethane formation through thiocarbonate ring-opening reactions with amino groups, thereby avoiding isocyanate-related safety and complexity issues while achieving the same functional outcomes.
2Adaptability or versatility
If additional heteroatoms or functionalities are incorporated into the polymer, then the technical application field is expanded, but the manufacturing complexity increases
Solution Approach 1:
The patent employs cyclic monothiocarbonate compounds that serve multiple functions simultaneously: they provide the urethane linkage formation through reaction with amino groups, introduce sulfur heteroatoms for enhanced functionality, and can incorporate silicon-functional groups for moisture curability. This multi-functionality in a single starting material expands application fields while avoiding the complexity of multiple separate additives.
Solution Approach 2:
The invention creates composite functionality within the polymer structure by incorporating compounds that contain multiple heteroatoms (sulfur from monothiocarbonate, silicon from functional groups, nitrogen from amino groups). This composite approach at the molecular level provides diverse technical applications while maintaining a relatively simple manufacturing process based on direct polymerization.
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 enables the economic and flexible preparation of silyl-modified polyurethanes with improved mechanical properties and expanded application fields, avoiding the use of isocyanates and providing polymers with silicon and sulfur functionalities.
Implementation Method 1
The ring system of the five-membered cyclic monothiocarbonate group of compound A) is opened by the amino group of compound B), resulting in an adduct comprising a urethane group and a group -SH
Implementation Method 2
The group -SH of the adduct may be further reacted with a -SH reactive group, notably a non-aromatic ethylenically unsaturated group or an epoxy group of compound C) or also of compounds A) and B)
Implementation Method 3
curing the silicon-functional groups with ambient water
Implementation Method 4
curing the silicon-functional groups with ambient water
Data Source
AI summary
Provided is a process for the preparation of a cross-linked polymer comprising urethane groups and silicon atoms, wherein a) a compound A) with a five-membered cyclic monothiocarbonate group and a compound B) with an amino group, selected from primary or secondary amino groups or blocked amino groups, and optionally a compound C) with at least one functional group that reacts with a group -SH are used as starting materials, whereby one of said compounds comprises a silicon- functional group, and wherein compounds A), B) and optionally C) are processed, for example, as follows by b1) reacting compounds A) and B) and optionally C) under exclusion of water to obtain a polymer with curable silicon-functional groups and b2) applying said polymer to a surface, gap or a three-dimensional template and curing the silicon-functional groups with ambient water. The polymer comprises 0.001 to 0.3 mol of silicon per 100 g of the polymer.