Latent Acid One-Component Silane Composition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing moisture-curing silane compositions have limited storage stability, cure too quickly in the presence of moisture, and require additional catalysts, which restrict their use and processing times, especially when combined with nitrogen-containing adhesion promoters or in industrial applications where prolonged open times are necessary.
Innovation Solution
A one-part composition comprising bifunctional and monofunctional silane compounds with a latent acid generator that remains liquid for extended periods without activation, curing only upon exposure to actinic radiation or heat, eliminating the need for additional catalysts and allowing for pre-activation and flexible processing times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If additional catalysts are added to accelerate curing, then curing speed is improved, but storage stability deteriorates and compatibility with nitrogen-containing adhesion promoters is lost
Solution Approach 1:
The patent applies preliminary action by incorporating the acid generator in latent form into the composition before use. The acid generator remains inactive during storage and only activates when exposed to actinic radiation or heat, thereby providing curing acceleration only when needed while maintaining storage stability throughout the product shelf life.
Solution Approach 2:
The patent utilizes parameter changes by transforming the acid generator from an active state to a latent state through chemical modification. The latent acid generator can be activated by changing physical parameters (exposure to actinic radiation or heat), allowing the system to transition between storage mode and curing mode, thus resolving the contradiction between storage stability and curing speed.
2Productivity
If catalysts are added to improve curing speed, then productivity is improved, but the composition becomes incompatible with nitrogen-containing adhesion promoters
Solution Approach 1:
The patent extracts the catalytic function from traditional metal-containing catalysts and transfers it to an organic acid generator system. This extraction eliminates the harmful interactions with nitrogen-containing adhesion promoters while preserving the curing acceleration capability, as the acid generator does not contain metal centers that would coordinate with nitrogen ligands.
Solution Approach 2:
The latent acid generator acts as an intermediary that mediates between the silane components and the adhesion promoters. It provides the necessary acidic catalysis for curing without directly interacting with or deactivating the nitrogen-containing adhesion promoters, thus enabling both fast curing and broad compatibility.
3Strength
If the composition cures quickly in the presence of moisture, then initial strength is improved, but processing time and flexibility are reduced
Solution Approach 1:
The patent applies preliminary action by pre-positioning the latent acid generator in the composition without immediate activation. This allows the composition to be applied and positioned during extended open times, and only after the desired positioning is achieved does activation occur, providing both processing flexibility and rapid initial strength development.
Solution Approach 2:
The patent implements dynamics by making the curing process controllable and adjustable. The latent acid generator allows the system to transition from a dormant state during application to an active curing state on demand, enabling dynamic control over when curing begins, thus optimizing both processing time and initial strength development.
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 long-term storage stability, remains liquid in the presence of moisture for up to 24 hours, and forms a skin quickly after activation, enabling flexible processing and high initial strengths without premature curing, suitable for bonding, sealing, and coating of various substrates, including non-radiolucent materials.
Implementation Method 1
at least one latent acid generator, in particular a photolatent acid generator, which can be activated and releases an acid upon exposure to actinic radiation or heat
Implementation Method 2
the composition...cures only upon irradiation and/or thermal activation of the acid generator
Implementation Method 3
moisture-curing compositions...curing only upon exposure to actinic radiation or heat
Data Source
AI summary
A composition curing upon exposure to moisture comprises (A) one or more at least bifunctional silane compounds with at least two alkoxysilane groups, (B) at least one monofunctional silane compound with only one alkoxysilane group, and/or a partially condensed or bridged derivative thereof, and (C) at least one acid generator which, upon exposure to actinic radiation or heat, releases an acid. In addition, further additives (D) may be contained in the compositions according to the present invention. The composition is liquid at room temperature and, apart from the latent acid generator, does not contain any further catalysts for moisture-curing of alkoxysilanes. After activation of the acid generator the composition cures in the presence of moisture, while remaining liquid at room temperature in the presence of humidity over a period of at least 24 hours prior to activation of the acid generator. Furthermore, a method of joining or casting structural elements using the composition is described.