Non-Organotin Curable Composition for Sealing Materials
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Solution Overview
Problem
Curable compositions containing organic polymers with reactive silicon groups face challenges in achieving good curability and adhesiveness when using non-organotin catalysts, particularly when metal carboxylates and amine compounds are combined, as they tend to degrade curability compared to organotin compounds.
Innovation Solution
A curable composition is developed using an organic polymer with three hydroxyl or hydrolyzable groups bonded to a silicon atom, combined with a metal carboxylate as a silanol condensation catalyst and a silane coupling agent without amino groups, to enhance curability and adhesiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal carboxylate and amine compound are combined as curing catalyst, then curability is improved compared to single catalyst, but curability is degraded compared to organotin compound
Solution Approach 1:
The patent changes the chemical parameters of the catalyst system by using metal carboxylate in combination with specific amine compounds (aliphatic, aromatic, or cyclic amines) in controlled amounts. This parameter change achieves non-organotin curability while maintaining adequate curing performance through optimized catalyst composition rather than relying on toxic organotin compounds.
2Reliability
If polymer with three hydrolyzable groups per silicon atom is used, then curability is improved, but adhesiveness and elongation are degraded
Solution Approach 1:
The patent applies local quality by using a mixed composition of silicon-containing polymers with different hydrolyzable group counts (two groups and three groups per silicon atom). This allows different regions of the cured product to exhibit different properties: high curability from the three-group polymer and good adhesiveness/elongation from the two-group polymer, achieving balanced overall performance.
Solution Approach 2:
The patent creates a composite curable composition by combining multiple silicon-containing polymers with different structural characteristics (different numbers of hydrolyzable groups per silicon atom). This composite approach allows the final cured product to integrate the advantages of each component polymer type, achieving both curability and adhesiveness.
3Reliability
If organotin compound is used as curing catalyst, then curability is superior, but toxicity issues arise
Solution Approach 1:
The patent replaces persistent toxic organotin compounds with alternative metal carboxylate catalysts combined with amine compounds. This substitution eliminates the harmful toxic effects while maintaining the curing function, using safer catalyst systems that achieve curability without the long-term toxicity concerns of organotin compounds.
Solution Approach 2:
The patent introduces amine compounds as intermediary substances that work in combination with metal carboxylate to achieve curability. The amine compound acts as a mediator that enhances the catalytic activity of the metal carboxylate, enabling effective curing without requiring toxic organotin compounds.
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 superior curability and adhesiveness while avoiding the toxicity issues associated with organotin compounds, demonstrating improved performance in sealing materials and adhesives.
Implementation Method 1
a polymer having a reactive silicon group crosslinks even at room temperature by the formation of a siloxane bond accompanying hydrolysis of the reactive silicon group due to moisture
Implementation Method 2
the formation of a siloxane bond accompanying hydrolysis of the reactive silicon group
Implementation Method 3
crosslinkable by forming a siloxane bond
Implementation Method 4
using metal carboxylate as a silanol condensation catalyst
Data Source
AI summary
Provision of a curable composition having good curability and adhesiveness by the use of a non-organotin catalyst.A curable composition containing an organic polymer (A) having a silicon-containing group crosslinkable by forming a siloxane bond, metal carboxylate (B), a silane coupling agent (C) free of an amino group, and an amino group-containing compound (D) in an amount corresponding to a weight ratio relative to (B) of 0-0.05, which contains, as the silicon-containing group of component (A), a silicon-containing group, wherein three hydrolyzable groups or hydroxyl groups are bonded to a silicon atom, as an essential component.