Curable Polyorganosiloxanes with Silane Endcapping for Adhesion and Stability
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Solution Overview
Problem
Current curable silicone compositions face challenges with moderate adhesion on certain substrates like plastics and concrete, and they often suffer from decreased storage stability due to the presence of conventional curing catalysts and adhesion promoters.
Innovation Solution
The development of curable polyorganosiloxanes with specific silane groups that release hydroxycarboxylic acid esters and amides during crosslinking, combined with a catalyst that enhances stability and adhesion properties, and optionally includes an adhesion promoter for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional curing catalysts and adhesion promoters are used in curable silicone compositions, then adhesion on certain substrates is improved, but storage stability deteriorates
Solution Approach 1:
The patent removes conventional curing catalysts and adhesion promoters from the composition during storage. The adhesion promoter is applied only after the composition is applied to the substrate, not during storage. This extraction of harmful components during the storage phase resolves the contradiction by eliminating the cause of degradation while preserving adhesion functionality when needed.
Solution Approach 2:
The patent performs preliminary endcapping of polyorganosiloxane with silane compounds to create stable precursor molecules that do not require conventional catalysts during storage. The composition is prepared in advance in a stable form, and curing is initiated only when applied, thus maintaining storage stability while enabling subsequent adhesion.
2Strength
If silane-based crosslinkers with hydrolyzable groups are used, then crosslinking and adhesion are improved, but aggressive compounds are released that corrode materials and create unpleasant odor
Solution Approach 1:
The patent changes the chemical parameters of the silane crosslinker system by selecting specific silane compounds that hydrolyze to form non-corrosive, odorless byproducts instead of aggressive compounds. This parameter change in the chemical composition resolves the contradiction by maintaining crosslinking functionality while eliminating harmful effects.
Solution Approach 2:
The patent converts the hydrolysis reaction that traditionally produces harmful compounds into a beneficial process by selecting silane crosslinkers whose hydrolysis products are non-corrosive and odorless. The water reaction that previously caused corrosion and odor now contributes to crosslinking without negative side effects, thus converting a harmful process into a beneficial one.
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 solution provides curable compositions with excellent storage stability and strong adhesion on various substrates, ensuring reliable curing at room temperature in the presence of atmospheric moisture.
Implementation Method 1
In the presence of atmospheric moisture these alkoxysilane-terminated polymers are able to condense with elimination of the alkoxy groups
Implementation Method 2
these alkoxysilane-terminated polymers are able to condense with elimination of the alkoxy groups
Data Source
AI summary
The invention relates to curable polyorganosiloxanes with special silicon-containing terminal groups and curable compositions based on these polyorganosiloxanes, a special capped adhesion promoter, and a curing catalyst. These compositions have improved adhesion properties and excellent storage stability. The invention also relates to the use thereof.