Curable Composition Using Silane-Modified Polymer and Lewis Acid Catalyst
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Solution Overview
Problem
Current curable compositions using non-organotin catalysts face challenges in achieving sufficient curability, especially when fillers are incorporated, and often result in unsuitable adhesiveness for sealants and adhesives.
Innovation Solution
A curable composition comprising a polymer with reactive silicon groups, a Lewis acid, an amine compound, and a specific compound with a reactive silicon group, along with a filler, which are mixed in a specific order and under controlled conditions to enhance crosslinking and adhesiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a non-organotin catalyst (such as amine compound and carboxylic acid combination) is used to avoid toxicity, then environmental friendliness is improved, but curability is insufficient especially when filler is used
Solution Approach 1:
The patent introduces a silane-modified polymer as an intermediary substance that bridges the gap between the non-toxic catalyst system and the curability requirement. This silane-modified polymer contains both silane groups that react with the catalyst and functional groups that enhance crosslinking, effectively mediating between the environmentally friendly catalyst and the need for sufficient curability even in the presence of fillers.
Solution Approach 2:
The patent creates a composite catalytic system combining amine compound, carboxylic acid, and silane-modified polymer. This composite approach integrates multiple functional components: the amine and carboxylic acid provide mild catalytic activity, while the silane-modified polymer contributes additional crosslinking capability, achieving sufficient curability without organotin catalysts.
2Reliability
If amine compound and carboxylic acid are used as catalysts to achieve curability, then curability is improved, but adhesiveness of cured products is insufficient
Solution Approach 1:
The silane-modified polymer acts as an intermediary that enhances the interaction between the catalyst system and the substrate. The silane groups form strong chemical bonds with both the polymer matrix and the substrate, while the amine and carboxylic acid groups provide catalytic activity, thereby improving adhesiveness without compromising curability.
Solution Approach 2:
The patent modifies the chemical parameters of the catalyst system by introducing silane-modified polymer with specific functional group concentrations and molecular weights. This parameter optimization ensures that the catalytic activity is sufficient for curability while the silane groups provide adequate bonding for adhesiveness.
3Strength
If filler is added to improve mechanical properties, then mechanical strength is improved, but curability becomes insufficient
Solution Approach 1:
The silane-modified polymer serves as an intermediary that facilitates the curing reaction in the presence of fillers. The silane groups react with the catalyst to form crosslinks that can bridge across filler particles, maintaining curability even when the filler content is high and would otherwise hinder the curing reaction.
Solution Approach 2:
The patent extracts the curability-enhancing function from the bulk polymer and concentrates it in the silane-modified polymer component. This allows the filler to be added to the composition without compromising curability, as the silane-modified polymer ensures sufficient crosslinking despite the presence of filler particles.
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 good curability and adhesiveness even when fillers are used, improving the industrial practicality and performance of the cured products.
Implementation Method 1
a polymer having at least one reactive silicon group in its molecule has a nature that the polymer is crosslinked through formation of siloxane bonds, which follows hydrolysis reaction or the like of the reactive silicon group due to moisture or the like
Implementation Method 2
Curable compositions containing a polymer having a reactive silicon group are cured by use of a curable catalyst
Data Source
AI summary
An object of the present invention is to provide a curable composition which is made mainly of a polymer having one or more reactive silicon groups, has good curability even when filler is used while a non-organotin catalyst is used, and is further high in industrial practicability. The object is solved by a curable composition, comprising, as constituents, a polymer (A) having one or more reactive silicon groups on average per molecule thereof, the reactive silicon group(s) being (each) a group which can be crosslinked by forming a siloxane bond, a Lewis acid and/or derivative thereof (B), an amine compound (C), a compound (D) having a reactive silicon group, and filler (E), and obtained by mixing the constituents with each other.