Silane-Terminated Polymer Network for Adhesion and Crosslink Control
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Solution Overview
Problem
Existing silane-terminated polymers lack optimal adhesion properties due to uniformity in crosslink density, limiting their effectiveness in adhesive and sealant applications.
Innovation Solution
A process involving a polymer with NCO groups reacting with a compound containing exactly one NCO-reactive group, followed by silane modification, to control crosslink density and enhance adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silane-terminated polymers are produced with uniform crosslink density, then the production process is simple, but the adhesion properties are insufficient
Solution Approach 1:
The patent applies local quality by creating non-uniform crosslink density within the polymer network. Specifically, it uses a bifunctional silane compound that reacts with NCO groups to form regions of different crosslink density, creating a heterogeneous structure where some areas have higher crosslinking (improving adhesion) while other areas maintain lower crosslinking (preserving flexibility and processability). This localized variation in crosslink density directly improves adhesion properties without requiring complex production processes.
2Strength
If the crosslink density is increased to improve adhesion, then the adhesion properties improve, but the polymer becomes more rigid and less processable
Solution Approach 1:
The patent resolves this contradiction by implementing local quality through spatial variation in crosslink density. The bifunctional silane compound creates localized crosslinked regions that enhance adhesion, while leaving other regions with lower crosslink density that maintain flexibility and processability. This localized approach allows the material to exhibit both improved adhesion and retained processability, avoiding the need to uniformly increase crosslink density throughout the entire polymer matrix.
Solution Approach 2:
The patent employs composite material principles by creating a heterogeneous polymer network with varying crosslink densities. The resulting structure can be viewed as a composite system where regions of high crosslinking (adhesive-rich) are distributed within a matrix of lower crosslinking (processable) regions. This composite structure at the molecular level allows simultaneous optimization of adhesion and processability properties that would be mutually exclusive in uniform systems.
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
Improves the adhesion properties of silane-terminated polymers by controlling crosslink density, resulting in enhanced performance as adhesives and sealants.
Implementation Method 1
which hydrolyze under the influence of moisture, condense with one another as silanol groups and thus form siloxane bonds
Implementation Method 2
condense with one another as silanol groups and thus form siloxane bonds
Implementation Method 3
reacting a polymer P1 comprising NCO groups with a compound C1 comprising exactly one NCO-reactive group
Data Source
AI summary
The present invention relates to a process for producing a polymer mixture, said process comprising: a) contacting a polymer P1 comprising NCO groups with an average NCO-functionality of at least two with a compound C1 comprising exactly one NCO-reactive group, with a molar ratio of NCO-reactive groups of C1 to NCO groups of P1 being from 0.01 to 0.9, so as to obtain a mixture M1; and b) contacting said mixture M1 with a silane comprising at least one NCO-reactive group. It also relates to a polymer mixture produced by such process, to a composition comprising such polymer mixture. It also relates to a sealant or adhesive formed from such composition.