Silylated Polyurea Thermal Stability Handling

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Solution Overview

Problem

Isocyanate-terminated polyurea compositions face challenges with handling, aerosol dispersal, and require two-component formulations with limited pot life, which complicates their use in coatings and sealants, and existing moisture-curable silylated resins have limitations in thermal stability and solvent resistance.

Innovation Solution

A moisture-curable silylated polyurea is developed by reacting organofunctional silanes with amine-terminated or isocyanate-terminated polyureas, resulting in a product with a high percentage of urea linkages, which enhances thermal stability and solvent resistance, and can be prepared without the need for two-component systems, thus simplifying handling and processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If isocyanate-terminated polyurea compositions are used, then rapid cure and high thermal stability are achieved, but handling difficulties and aerosol dispersal issues occur

Engineering Contradiction:

Improvethermal stabilityVSAvoidhandling

Core Design Contradiction:

TemperatureVSEase of operation

Solution Approach 1:

The invention changes the chemical parameters by using amine-terminated polyurea instead of isocyanate-terminated polyurea, and by incorporating hydrolyzable silane groups. This parameter change maintains thermal stability while eliminating the handling and aerosol dispersal issues associated with unreacted polyisocyanates.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention converts the potential harm of unreacted polyisocyanates (handling difficulties, aerosol dispersal) into a benefit by using amine-terminated polyurea with hydrolyzable silane groups that cure with moisture, eliminating the harmful unreacted isocyanates while maintaining the desired performance.

Inventive Principle:

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

2Temperature

If two-component polyurea formulations are used, then rapid cure and high thermal stability are achieved, but device complexity and limited pot life occur

Engineering Contradiction:

Improvethermal stabilityVSAvoidformulation complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The invention merges the polyurea formation and silane curing functions into a single-component system. The amine-terminated polyurea with hydrolyzable silane groups combines both functionalities, eliminating the need for separate components and simplifying the formulation while maintaining thermal stability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The amine-terminated polyurea with hydrolyzable silane groups serves multiple functions: it provides the polyurea structure for thermal stability and simultaneously contains the hydrolyzable silane groups for moisture-curable crosslinking, creating a multi-functional single-component system.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If silylated polyurethane-polyurea resins are used, then moisture curability is achieved, but thermal stability decreases due to significant numbers of urethane linkages

Engineering Contradiction:

Improvemoisture curabilityVSAvoidthermal stability

Core Design Contradiction:

Ease of operationVSTemperature

Solution Approach 1:

The invention applies local quality by ensuring that the polyurea segments have high urea linkage content (80-100 equivalent percent) while the silane groups are incorporated at specific locations. This localized approach maintains high thermal stability in the polyurea regions while enabling moisture curability through the hydrolyzable silane groups.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention creates a composite material structure combining polyurea segments with high urea linkage content and hydrolyzable silane groups. This composite structure achieves both moisture curability and high thermal stability by integrating the beneficial properties of both components.

Inventive Principle:

Principle #40Composite materials

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 silylated polyurea exhibits improved thermal stability and solvent resistance, enabling its use in applications with high temperatures and reducing production costs due to faster reactivity, while avoiding the handling issues associated with polyisocyanates.

Implementation Method 1

organofunctional silane (a) possessing hydrolyzable functionality

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

the reaction product of at least one organofunctional silane (a) possessing hydrolyzable functionality and at least one amine-terminated or isocyanate-terminated polyurea (b)

Methodology Applied

Scientific EffectCondensation reaction:

Data Source

PatentEP2231740B1Moisture-curable silylated polyurea and adhesive, sealant and coating compositions containing same

Publication Date: 2011.08.24 MOMENTIVE PERFORMANCE MATERIALS INC

AI summary

A moisture-curable, optionally cured, silylated polyurea possessing an average of from 80 to 100 equivalent percent of urea linkages based on the total equivalents of urea and urethane linkages therein is the reaction product of organofunctional silane (a) possessing hydrolyzable functionality and at least one polyurea (b) possessing amine termination or isocyanate termination, polyurea (b) being obtained from the reaction of at least one polyamine (c) and at least one polyisocyanate (d) in the substantial absence of silane (a).