Ionic Silylated Copolyurethane Adhesive Process

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Solution Overview

Problem

Current silylated polyurethanes, such as SPURs, have limitations in crosslinking time and mechanical properties, particularly requiring toxic tin-based catalysts and not achieving sufficient elongation at break for advanced applications like construction and automotive industries.

Innovation Solution

A process for preparing ionic silylated copolyurethanes with ureido-alkylene-alkoxysilane terminal groups, involving a polyaddition reaction between a polyisocyanate, polyols, and a carboxylic diol, followed by neutralization with a tertiary amine and reaction with an aminosilane, to form a crosslinkable adhesive without the need for tin-based or nitrogen heterocycle catalysts, achieving enhanced mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If tin-based catalysts are used to accelerate crosslinking, then crosslinking time is reduced, but toxicity and environmental impact increase

Engineering Contradiction:

Improvecrosslinking timeVSAvoidtoxicity

Core Design Contradiction:

Loss of timeVSObject-affected harmful factors

Solution Approach 1:

The patent removes the harmful tin-based catalyst from the crosslinking process while maintaining acceptable crosslinking time through optimized formulation of the silylated polyurethane composition, thereby eliminating toxicity while preserving the crosslinking function

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs alternative catalyst systems that are less toxic and more environmentally friendly than tin-based catalysts, sacrificing some catalytic efficiency but gaining in safety and environmental compatibility

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Loss of time

If nitrogen heterocycle crosslinking catalysts are used, then crosslinking time is reduced, but the adhesive joint undergoes color change to yellowish hue

Engineering Contradiction:

Improvecrosslinking timeVSAvoidaesthetic quality

Core Design Contradiction:

Loss of timeVSEase of manufacture

Solution Approach 1:

The patent extracts the nitrogen heterocycle catalyst that causes yellowing while maintaining crosslinking functionality through alternative formulations, thereby preserving the aesthetic quality of the adhesive joint

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces alternative catalyst systems or formulation additives that mediate the crosslinking process without causing the undesirable yellowing effect, acting as intermediaries that enable crosslinking while preserving color stability

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If conventional silylated polyurethanes are used, then crosslinking reactivity is achieved, but elongation at break remains insufficient for advanced applications

Engineering Contradiction:

Improvecrosslinking reactivityVSAvoidelongation at break

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The patent modifies the chemical structure and composition parameters of the silylated polyurethane, including the selection of specific polyols, isocyanates, and silane modifiers, to simultaneously achieve rapid crosslinking and high elongation at break exceeding 200%

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite molecular structure combining polyurethane chains with grafted silane groups that provide both crosslinking reactivity and enhanced elastomeric properties, resulting in a material that exhibits both rapid curing and superior elongation

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 adhesive joint exhibits improved elongation at break (up to 200%) and breaking stress (at least 3 MPa), comparable crosslinking time, and avoids catalyst-related toxicity issues, making it suitable for demanding industrial applications.

Implementation Method 1

forming an isocyanate-terminated polyurethane, by implementing a polyaddition reaction of a polyether diol with a polyisocyanate

Methodology Applied

Scientific EffectPolyaddition reaction: Chemical Bonding

Implementation Method 2

by hydrolysis of the alkoxysilane groups carried by the prepolymer

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

then their condensation to form a siloxane bond (-Si-O-Si-) which unites the prepolymer chains into a three-dimensional polymeric network

Methodology Applied

Scientific EffectCondensation reaction: Chemical Bonding

Data Source

PatentEP4177285A1Process for preparing silylated ionic polyurethanes with improved elasticity

Publication Date: 2023.05.10 BOSTIK SA(FR)

AI summary

1) Process for preparing ionic silylated copolyurethanes comprising 2 ureido-alkylene-alkoxysilane terminal groups comprising: (i) the formation of -NCO-terminated copolyurethanes by polyaddition reaction between a polyisocyanate, a carboxylic diol and a polyol composition comprising a polyol of Mn greater than or equal to 2500 g/mol and a polyol of Mn less than 2500 g/mol; (ii) the neutralization of the product formed with a tertiary amine, (iii) a reaction with an aminosilane derived from a secondary amine 2) Composition of ionic silylated copolyurethanes comprising 2 ureido-alkylene-alkoxysilane terminal groups, capable of being obtained by the process 3) Crosslinkable adhesive and/or sealant composition comprising composition 2) and a filler.