Thermolatent Tin Catalyst for Curable Compositions
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Solution Overview
Problem
In the field of curable compositions, there is a challenge in balancing pot life and cure speed, as higher catalyst concentrations accelerate curing but shorten pot life, while lower concentrations slow down curing and extend pot life, making it difficult to achieve both efficiently and effectively.
Innovation Solution
The development of thermolatently catalytic tin-containing compounds that remain inactive at ambient temperatures but become catalytically active upon heating, allowing for controlled curing reactions without prematurely increasing viscosity, thus optimizing both pot life and cure speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If higher catalyst concentrations are used to accelerate curing, then cure speed is improved, but pot life is shortened
Solution Approach 1:
The patent applies parameter changes by utilizing temperature as a controlling parameter for catalyst activity. The tin catalyst remains inactive at ambient temperatures (maintaining long pot life) but becomes highly active when temperature is increased to moderate levels (accelerating cure speed). This resolves the contradiction by changing the physical state/energy level of the system rather than changing catalyst concentration.
Solution Approach 2:
The patent implements dynamics by making the catalyst activity dynamic and controllable through temperature variation. The catalyst transitions from an inactive state during storage and mixing to an active state during curing, allowing the system to adapt its curing rate based on temperature conditions rather than being fixed by catalyst concentration alone.
2Loss of time
If additional catalyst is added to speed up drying and cure, then dust-free time is reduced, but pot life is shortened due to increased viscosity
Solution Approach 1:
The patent resolves this contradiction by changing the temperature parameter to control catalyst activation. The catalyst remains dormant at ambient temperatures, allowing extended pot life for spraying operations, then activates at moderate temperatures to rapidly reduce dust-free time. This eliminates the need to add more catalyst and avoids the viscosity increase problem.
Solution Approach 2:
The patent introduces temperature as an intermediary control mechanism between the catalyst and the curing reaction. By using temperature as the mediator, the system can selectively activate the catalyst only when desired (during the curing phase after application), preventing premature viscosity increase while ensuring rapid cure when needed.
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
These compounds enable a longer pot life while ensuring efficient curing at moderate temperatures, maintaining stability during storage and rapid activation upon heating, allowing for effective use in various applications such as coatings and film-forming compositions.
Implementation Method 1
Catalysis is an initiation or a change in the rate of a chemical reaction due to the participation of a material called a catalyst. Catalysts that speed the reaction are called positive catalysts.
Implementation Method 2
thermolatently catalytic tin-containing compounds that remain inactive at ambient temperatures but become catalytically active upon heating
Data Source
AI summary
Tin-containing catalysts are provided comprising a compound of formula I. L1, L2, L3, and L4 are each independently selected from -O-, -S-, -OC(=O)-, -OC(=S)-, -SC(=O)-, -SC(=S)-, -OS(=O)2O-, -OS(=O)2- -N(R6)-, and -OP(=O)(R6)-, wherein R6 represents hydrogen or a monovalent aliphatic, araliphatic, cycloaliphatic or aromatic group having up to 20 carbon atoms. R1, R2, R3, R1', R2', and R3' each independently represent a divalent aliphatic, araliphatic, cycloaliphatic or aromatic group having up to 20 carbon atoms; and R4, R5, R4', and R5' each independently represent hydrogen or a monovalent residue derived from reaction of a respective N-H group with an isocyanate, an ethylenically unsaturated compound, a lactone, a dilactone, a thiolactone, a lactam, a thiolactam, a carboxylic acid or derivative thereof, or an epoxide. Also provided are curable compositions containing these catalysts and methods of controlling the rate of cure of curable compositions.