Silane Modified Terpolymer Adhesive Viscosity and Strength
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Solution Overview
Problem
Existing silane modified polymers used in adhesive compositions often exhibit high viscosity, low adhesion, and poor low-temperature performance, which limits their practical application in commercial uses.
Innovation Solution
A moisture-curable silane modified terpolymer is developed, comprising a polyether segment, a polysiloxane segment, and a polytetrahydrofuran or polycarbonate segment, covalently bonded by urethane linkages and terminated with silyl hydrolysable groups, which is synthesized through a two-step process involving isocyanate termination and amino silane reaction, resulting in a composition with improved adhesion and tensile strength while maintaining low viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silane modified polymers are used to improve adhesion in adhesive compositions, then adhesion is enhanced, but viscosity increases
Solution Approach 1:
The patent segments the polymer structure into distinct blocks: polyether segments providing flexibility and low temperature performance, polysiloxane segments providing adhesion and moisture curability, and polytetrahydrofuran or polycarbonate segments contributing to tensile strength. This segmentation allows each block to contribute its specific properties without the entire polymer chain becoming excessively viscous, as the segmented structure maintains better chain mobility compared to a fully crosslinked or homogeneous high-crosslink-density structure.
Solution Approach 2:
The patent applies local quality by concentrating the reactive silyl groups at specific locations (chain ends or side chains) rather than uniformly distributing them throughout the polymer structure. This localized placement of hydrolyzable substituents enables adhesion enhancement at the interface while maintaining lower overall viscosity in the bulk polymer, as the majority of the polymer chain retains its base polymer characteristics with lower inherent viscosity.
2Strength
If crosslinking density is increased to improve tensile strength, then tensile strength is enhanced, but low temperature performance deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the polymer by incorporating polyether segments with low glass transition temperatures. These polyether blocks remain flexible at low temperatures, preventing the entire polymer system from becoming brittle. The parameter change in composition (adding柔韧 polyether segments) allows the material to maintain tensile strength through controlled crosslinking while preserving low-temperature flexibility through the inherent properties of the polyether segments.
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 silane modified terpolymer achieves enhanced adhesion, tensile strength, and low-temperature performance with reduced viscosity, making it suitable for commercial adhesive applications.
Implementation Method 1
In the presence of atmospheric moisture, polymers having silyl groups with hydrolyzable substituents are capable of condensing with one another at room temperature, splitting off the hydrolyzed residues
Implementation Method 2
polymers having silyl groups with hydrolyzable substituents are capable of condensing with one another at room temperature
Implementation Method 3
The silane modified terpolymer comprises: at least one polyether segment... at least one segment selected from a polytetrahydrofuran segment or a polycarbonate segment... covalently bonded to an adjacent segment by a urethane linkage
Implementation Method 4
at least one terminal silyl hydrolysable group connected to the polymer via an isocyanate linkage
Data Source
AI summary
Disclosed is a moisture curable silane modified terpolymer comprising a polyether segment, a segment of polytetrahydrofuran or polycarbonate, a polysiloxane segment and terminal amino silane groups joined to the terpolymer via urethane linkages and wherein the polyether segment comprises at least 70% by weight based on the total weight of the silane modified terpolymer. Also disclosed is a method of forming moisture curable silane modified terpolymer.