Silyl-Modified Polyoxyalkylene Polymer for Strength and Curability
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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 methallyl groups, which inhibit hydrolysis and condensation, and limited molecular weight production when using allyl groups.
Innovation Solution
A polyoxyalkylene polymer with a high molecular weight and a specific hydrolyzable silyl group-containing structure, represented by formula (1), is produced through hydrosilylation with a ruthenium complex to suppress side reactions and enhance silyl group introduction, ensuring high strength and curability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If hydrosilylation of allyl groups is performed with a metal catalyst, then silyl groups are introduced into the polymer, but side reactions occur (isomerization and hydrogenation) limiting the degree of silyl group introduction to around 80%
Solution Approach 1:
The patent changes the chemical structure parameter by using methallyl groups instead of allyl groups, and changes the catalyst parameter by using a ruthenium complex instead of traditional metal catalysts. This combination achieves a degree of silyl group introduction of 90-97% while suppressing side reactions to below 5%, resolving the contradiction between quantity of silyl groups and harmful side reactions.
2Strength
If hydrosilylation of methallyl groups is performed to increase degree of silyl group introduction to 90-97%, then strength after curing is enhanced, but the rate of hydrolysis and condensation slows down due to steric hindrance from methyl groups
Solution Approach 1:
The patent optimizes the molecular weight parameter of the polyoxyalkylene polymer to be 3,000 or more, which balances the steric hindrance effect. At this molecular weight range, the polymer achieves high strength after curing while maintaining an acceptable rate of hydrolysis and condensation, resolving the contradiction between strength and curing speed.
3Strength
If molecular weight of silylated derivative is increased beyond 3,000, then strength after curing improves, but side reactions increase and selectivity for silylated derivative production decreases
Solution Approach 1:
The patent uses a ruthenium complex as an intermediary catalyst that enables high-selectivity hydrosilylation reactions even at molecular weights of 3,000 or more. This catalyst mediates the reaction to maintain selectivity for silylated derivative production while allowing the polymer to achieve high molecular weight and corresponding strength.
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 polymer achieves high strength and good curability, with a high proportion of hydrolyzable silyl group-containing structures, suitable for applications in adhesives, sealing materials, and pressure-sensitive adhesives.
Implementation Method 1
hydrosilylation of an allyl group-containing polyoxyalkylene polymer with a hydrosilane compound in the presence of a metal catalyst
Implementation Method 2
hydrosilylation of allyl groups results in a degree of silyl group introduction of around 80%
Implementation Method 3
Polymers of this type cure via hydrolysis to form flexible, rubber-like cured products
Implementation Method 4
hydrolysis and condensation of the hydrolyzable silyl groups
Data Source
AI summary
A polyoxyalkylene polymer contains a polyoxyalkylene polymer molecule having a hydrolyzable silyl group-containing structure represented by the following formula (1): 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, I-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.