Titanium Amide Catalysts for Siloxane Bonding
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Solution Overview
Problem
Current titanium-based catalysts for curing silicon-containing polymers lack sufficient catalytic activity and stability, particularly when used with aminosilanes as adhesion promoters, resulting in suboptimal storage stability and hardness of cured products.
Innovation Solution
Development of curable compositions comprising specific titanium compounds, such as Ti(OR4)3(NX2)m and Ti(R3)(L)3, which are compatible with aminosilanes and enhance catalytic activity, stability, and crosslinking efficiency, forming siloxane bonds in silicon-containing polymers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If known titanium compounds are used as condensation catalysts, then catalytic activity is provided, but stability and compatibility with aminosilanes are insufficient
Solution Approach 1:
The patent modifies the chemical structure of titanium catalysts by changing ligand parameters - specifically using amide ligands (NX2) instead of traditional alkoxide ligands. This parameter change in the catalyst structure improves compatibility with aminosilanes while maintaining catalytic activity and enhancing storage stability.
Solution Approach 2:
The invention creates composite catalyst structures combining titanium center with specific amide ligands and hydrolyzable groups. This composite approach integrates multiple functional properties - catalytic activity from titanium, stability from amide ligands, and compatibility with aminosilanes - into a single catalyst molecule.
2Productivity
If traditional titanium esters are used as catalysts, then curing is enabled, but catalytic activity and storage stability are insufficient
Solution Approach 1:
The patent changes the ligand parameters from simple alkoxides to amide ligands with specific structural features. This parameter modification enhances both catalytic activity through improved substrate interaction and storage stability through stronger Ti-N bonding compared to Ti-O bonds in traditional esters.
3Reliability
If organotin compounds are used as catalysts, then excellent storage stability and curing performance are achieved, but toxicological concerns arise
Solution Approach 1:
The patent replaces persistent organotin compounds with titanium-based catalysts that can be more easily disposed of or degraded. While the titanium catalyst serves its function, it presents lower long-term environmental and toxicological concerns compared to organotin compounds, allowing for safer end-of-life handling.
Solution Approach 2:
The invention converts the historical advantage of organotin compounds (excellent stability) into a design target for titanium catalysts, while transforming the disadvantage (toxicity) into a motivation for selecting environmentally benign titanium-based alternatives with appropriate ligand design to achieve comparable stability.
4Productivity
If known titanium catalysts are used, then curing is facilitated, but hardness of cured products is low
Solution Approach 1:
The patent modifies catalyst structure parameters - specifically incorporating amide ligands with specific electronic and steric properties - to optimize the curing process. These parameter changes promote more effective crosslinking reactions that generate higher hardness in the cured products while maintaining good curing efficiency.
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 proposed titanium compounds demonstrate improved catalytic activity and stability, leading to enhanced storage stability and increased hardness of cured products, addressing the limitations of existing titanium-based catalysts.
Implementation Method 1
titanium-based hydrolysis catalysts
Implementation Method 2
silicon-containing groups of formula (1) —Si(R1)k(Y)3-k where each Y is independently a hydroxy group or a hydrolyzable group
Implementation Method 3
curing polymers containing reactive silicon groups, which meet the above-described requirements, i.e., which have sufficient catalytic activity and stability and which are compatible with the aminosilanes customarily used as adhesion promoters
Data Source
AI summary
The invention relates to a curable composition comprising: a) at least one polymer having at least one silicon-containing group of formula —Si(R1)k(Y)3-k as defined herein; b) at least one titanium compound of formula Ti(L)n(NX2)m or Ti(R3)(L)3, where each X is independently a hydrogen atom, a hydrocarbon radical containing 1 to 20 C atoms, which may optionally contain one or more heteroatoms, in particular nitrogen atoms, or a silicon-containing organic group, or two X together with the nitrogen atom to which they are bound form a heterocyclic ring; each L is independently a hydrolyzable oxygen- or nitrogen-containing organic group, in particular an alkoxy group; R3 is a hydrocarbon radical containing 1 to 20 C atoms, which may optionally contain one or more heteroatoms, in particular silicon atoms; and m is 1, 2, 3, or 4 and and n is 0, 1, 2, or 3, where m+n=4; and c) optionally at least one compound which has a hydrolyzable silicon-containing group and a molecular weight in the range of 100 to 1000 g/mol, preparations containing these compositions and use thereof.