Silyl-Modified Polyoxyalkylene Polymer for Selective Hydrosilylation
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Solution Overview
Problem
Existing hydrolyzable silyl group-containing polyoxyalkylene polymers face challenges in achieving both high strength after curing and good curability due to side reactions during hydrosilylation, particularly when using metal catalysts like the Karstedt catalyst, which limits the degree of silyl group introduction and affects the properties of the cured product.
Innovation Solution
A polyoxyalkylene polymer with a high proportion of hydrolyzable silyl group-containing structures represented by formula (1), produced through hydrosilylation of an allyl group-containing polymer using a ruthenium complex, minimizes side reactions and achieves a high degree of silyl group introduction, resulting in a polymer with a molecular weight over 3,000 and improved curability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If hydrosilylation of allyl groups is performed using a Karstedt catalyst, then the polymer can be cured to form a rubber-like product, but side reactions occur limiting the degree of silyl group introduction to around 80%
Solution Approach 1:
The patent changes the catalyst parameter from a Karstedt catalyst (platinum-based) to a ruthenium complex catalyst. This parameter change in the catalytic system enables high-degree silyl group introduction (90% or more) while preventing side reactions, thereby resolving the contradiction between achieving high silyl group introduction and maintaining manufacturing precision.
2Manufacturing precision
If hydrosilylation of methallyl groups is performed to increase degree of silyl group introduction to 90-97%, then silyl group introduction improves, but the curing reaction rate decreases due to steric hindrance from methyl groups
Solution Approach 1:
The patent uses local quality by selecting a specific ruthenium complex catalyst that provides selective catalysis for allyl groups while being less sensitive to steric hindrance compared to other catalysts. This localized catalytic activity at the ruthenium center enables high silyl group introduction without the steric hindrance penalty that affects general catalyst systems.
3Strength
If the molecular weight of the silylated derivative is increased beyond 3,000, then the polymer exhibits better mechanical properties, but side reactions increase and selectivity decreases
Solution Approach 1:
The ruthenium complex acts as an intermediary that mediates the hydrosilylation reaction with high selectivity even for high molecular weight polymers. This intermediary catalyst enables the reaction to proceed selectively at the allyl groups without causing side reactions, allowing the production of high molecular weight polymers (Mn > 3,000) with maintained selectivity.
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 polymer exhibits high strength and good curability, enabling the production of cured products with enhanced mechanical properties such as tensile strength and elongation.
Implementation Method 1
hydrosilylation of an allyl group-containing polyoxyalkylene polymer with a hydrosilane compound in the presence of a ruthenium complex
Implementation Method 2
A polyoxyalkylene polymer that has a silyl group having a hydroxy or hydrolyzable group on a silicon atom and capable of forming a siloxane bond
Data Source
AI summary
A polyoxyalkylene polymer containing a polyoxyalkylene polymer molecule having a hydrolyzable silyl group-containing structure represented by the following formula (1) is provided.The proportion of the number of the hydrolyzable silyl group-containing structures represented by the formula (1), as measured relative to the total number of hydrolyzable silyl groups, 1-propenyl groups, propyl groups, and allyl groups in the polymer, is from 0.85 to 1.00, and the polymer has a number-average molecular weight of more than 3,000. In the formula (1), R groups are the same or different and are each a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, X groups are the same or different and are each a hydroxy group or a hydrolyzable group, and a is 0, 1, or 2.