Moisture-Curing Adhesive Formulation with Time-Modified Curing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current adhesives and sealants lack a balance between broad adhesion, good elasticity, and rapid curing, often requiring rapid processing with limited correction time and compromising on adhesion or elastic properties.
Innovation Solution
A curable composition comprising polyether or polyacrylic acid esters with silyl-terminated end groups and an organotin compound, along with a compound lacking tin and silicon, which provides extended processing time and rapid curing, ensuring strong and elastic bonds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If curing catalysts are added to enable rapid curing, then curing speed is improved, but processing phase duration deteriorates
Solution Approach 1:
The patent introduces an intermediary substance that selectively interacts with the curing catalyst to modulate its activity. This intermediary acts as a temporary buffer that prevents the catalyst from immediately activating all reactive groups, thereby extending the processing phase while still enabling subsequent rapid curing when the intermediary is consumed or deactivated.
Solution Approach 2:
The curing process is designed to occur in distinct periods: an initial extended processing phase where curing is suppressed or slowed, followed by a rapid curing phase. This periodic control of the curing reaction allows users to work with the adhesive in its uncured state for an extended period, then triggers fast curing when needed.
2Loss of time
If fast-curing systems are used, then curing time is reduced, but correction options deteriorate
Solution Approach 1:
The adhesive formulation includes preliminary components (such as moisture-reactive groups or catalyst modifiers) that are designed to remain dormant during the extended processing phase. This preliminary configuration allows the adhesive to be applied and repositioned freely, then triggers the curing reaction only after the desired positioning is achieved, providing correction options while maintaining fast final curing.
3Ease of operation
If extended processing phase is provided, then ease of operation is improved, but curing speed deteriorates
Solution Approach 1:
The patent employs parameter changes in the form of pH-sensitive or moisture-sensitive catalyst activation. The curing catalyst remains in a low-activity state during the extended processing phase, then undergoes a parameter change (such as pH shift or moisture exposure) that dramatically increases its catalytic activity, enabling rapid curing afterward. This parameter transition allows both extended processing and fast curing to coexist.
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 composition achieves excellent adhesion and elasticity, allowing for extended correction time before curing, resulting in stable and resilient bonds with balanced properties.
Implementation Method 1
In the presence of atmospheric moisture, polymers that have silyl groups with hydrolyzable substituents are able to condense with one another at room temperature, eliminating the hydrolyzed residues.
Implementation Method 2
polymers that have silyl groups with hydrolyzable substituents are able to condense with one another at room temperature, eliminating the hydrolyzed residues
Implementation Method 3
In order to enable rapid curing of the compositions after bonding, curing catalysts are usually added to the formulations, which are usually organometallics, for example based on tin or iron.
Implementation Method 4
DE-OS 1956672 describes multi-component adhesives based on polyisocyanates and polyhydroxy compounds, which contain an organotin curing rate catalyst and a time catalysis modifier from the group of β-dicarbonyl compounds, α-hydroxy ketones, condensed aromatic β-hydroxy ketones and Nitrogen heterocyclic, fused aromatic β-hydroxy compounds
Data Source
AI summary
The invention aims to allow a curable composition to have an extended working phase followed by a short time period in which said compound becomes fully cured. This is achieved by the provision of a curable composition comprising the following components: a) at least one polyether and/or at least one polyacrylic acid ester with at least one reactive silyl group as an end-group; b) at least one organotin compound; and c) at least one compound that does not contain any tin or silicon atoms and that has at least two functional groups. Said groups are selected from the following: carboxy, carbonyl or hydroxy groups, or nitrogen atoms that are part of a ring system with aromatic character. In addition, the invention relates to a method for producing such a composition, and to the use thereof as an adhesive, a sealant or as a coating material.