Silane-Functional Polymer Synthesis via Hydroxysilane Extraction

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Solution Overview

Problem

Polymers containing silane groups used in construction and industrial applications often have high viscosities and limited thermal stability, and existing methods for preparing hydroxysilanes are inefficient due to self-condensation and short shelf life, leading to inadequate storage stability and thermal performance.

Innovation Solution

A polymer with end groups of a specific formula that can be prepared from hydroxysilanes and polyurethane polymers containing isocyanate groups, which are reactive with moisture to form a crosslinked material with low viscosity, good storage stability, and high thermal stability, using a process that avoids isocyanate groups to reduce toxicity and improve purity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If polymers containing silane groups are prepared via reaction of polyurethane polymers with aminosilanes, then silane-functional polymers can be obtained, but the polymers have high viscosities and limited thermal stability due to urea groups formed in the reaction

Engineering Contradiction:

Improvemanufacturability of silane-functional polymersVSAvoidthermal stability

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The invention extracts and eliminates the harmful urea groups formed during aminosilane reaction by using hydroxysilanes instead, which form urethane bonds that do not produce urea byproducts, thereby resolving the thermal stability issue while maintaining ease of manufacture

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the chemical parameter of the silane coupling agent from aminosilane to hydroxysilane, which fundamentally alters the reaction pathway from urea bond formation to urethane bond formation, improving thermal stability without sacrificing manufacturability

Inventive Principle:

Principle #35Parameter changes

2Strength

If polymers containing silane groups are prepared via reaction of polyurethane polymers with hydroxysilanes, then polymers with better viscosity and thermal stability properties can be obtained, but hydroxysilanes have short shelf life and are impure due to self-condensation

Engineering Contradiction:

Improvethermal stability and viscosity propertiesVSAvoidstorage stability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The invention performs preliminary protection of the hydroxysilane groups by converting them to stable ether derivatives before storage and application. The hydroxysilane is first reacted with a polyol to form a protected intermediate that is storage-stable, and only upon contact with moisture during application does the protection is removed and the silane becomes active

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention introduces a polyol as an intermediary substance that mediates between the hydroxysilane and the final polymer product. The polyol temporarily binds to the hydroxysilane in a reversible manner, preventing self-condensation during storage while allowing the silane to react with the polyurethane polymer when needed

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If isocyanatosilanes are used to prepare silane-functional polymers, then the route is commercially attractive, but isocyanatosilanes are costly, have short shelf life and are highly toxic

Engineering Contradiction:

Improvecommercial attractivenessVSAvoidtoxicity

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention replaces expensive, toxic, and short-lived isocyanatosilanes with cheaper, less toxic hydroxysilanes that can be stored for longer periods. The hydroxysilane serves as a disposable intermediate that is converted to the active form only when needed, eliminating the need to handle and store hazardous materials

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention converts the naturally occurring self-condensation tendency of hydroxysilanes, which was previously a harmful issue, into a beneficial feature by controlling the timing of condensation. The hydroxysilane's reactivity is harnessed to drive the coupling reaction with the polyurethane polymer while preventing unwanted side reactions through proper formulation and storage conditions

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 cures rapidly with moisture to form a nontacky, elastic material with high strength and extensibility, maintaining thermal stability even at elevated temperatures, and is suitable for use in adhesives, sealants, and coatings with improved storage and processing properties.

Implementation Method 1

reactive with moisture to form a crosslinked material

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

crosslinks rapidly with moisture

Methodology Applied

Scientific EffectCondensation: Condensation

Data Source

PatentUS10246546B2Polymer containing silane groups

Publication Date: 2019.04.02 SIKA TECH AG

AI summary

A polymer containing silane groups, a method for synthesizing same, and curable compositions including the polymer. The polymer containing silane groups has a very long shelf life and cures quickly with moisture. The polymer is suitable as an elastic adhesive or sealant or coating that can be applied at room temperature and has good heat resistance, or as a hot melt adhesive.