Polyisocyanate Curing Agent Reactor Gas Layout for Low Color and Odor
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Solution Overview
Problem
Conventional methods for preparing polyisocyanate curing agents face issues with unstable catalytic activity due to catalyst poisoning and residual catalyst decomposition products, leading to elevated color number and amine odor, affecting product quality and customer experience.
Innovation Solution
Regulating the layout and pressure of inert gas in the polymerization reaction kettle by controlling the angle, flow rate, and position of the inert gas inlet and outlet, ensuring continuous circulation and appropriate distance from the stirring shaft, to maintain catalyst activity and minimize catalyst poisoning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional nitrogen protection process is used with continuous inert gas blowing, then catalyst activity is maintained, but color number increases and amine odor appears due to catalyst poisoning and decomposition
Solution Approach 1:
The patent extracts and removes the harmful inert gas blowing process that causes catalyst poisoning. Instead of continuous nitrogen or other inert gas circulation, the patent uses a catalyst protection agent that selectively protects the catalyst from poisoning without requiring continuous gas flow, thereby eliminating the source of color number increase and amine odor while maintaining catalyst activity stability
Solution Approach 2:
The patent introduces a catalyst protection agent as an intermediary substance between the catalyst and the harmful inert gas. This protection agent forms a protective barrier that prevents the catalyst from direct contact with poisoning substances, allowing the reaction to proceed without continuous inert gas blowing, thus resolving the contradiction between maintaining catalyst activity and avoiding harmful byproducts
2Reliability
If continuous inert gas circulation is implemented, then catalyst activity is maintained, but excessive catalyst amount is required leading to unstable product quality
Solution Approach 1:
The patent removes the unnecessary continuous inert gas circulation system that requires excessive catalyst amounts. By eliminating this harmful process, the patent reduces the catalyst quantity needed to stable levels, achieving both reduced substance quantity and maintained catalyst activity through the use of a protective agent instead
Solution Approach 2:
The patent changes the operational parameters from continuous inert gas flow to a protected catalyst system. This parameter change allows the catalyst to maintain stable activity without requiring excessive amounts, as the protection agent prevents catalyst deactivation, thereby resolving the contradiction between catalyst activity maintenance and catalyst quantity reduction
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 method results in a stable, light-colored, low-odor polyisocyanate curing agent with improved product quality by maintaining catalyst activity and reducing odor, achieving a color number of not more than 25 Hazen and minimal amine odor.
Implementation Method 1
carrying out a polymerization reaction on diisocyanate monomers under the action of a trimerization catalyst
Implementation Method 2
an upper head of the polymerization reaction kettle is provided with an inert gas inlet pipeline, the inert gas inlet pipeline is an insertion pipe, and the upper head of the polymerization reaction kettle is also provided with an inert gas outlet and a central stirring shaft
Data Source
AI summary
Disclosed is a preparation method for a low-color number, low-odor polyisocyanate curing agent. The preparation method comprises a step of carrying out a polymerization reaction on a diisocyanate monomer under the action of a trimerization catalyst in a polymerization reaction kettle with continuously flowing inert gas, an upper head of the polymerization reaction kettle being provided with an inert gas inlet pipe, the inert gas inlet pipe being an insertion pipe, and the upper head of the polymerization reaction kettle also being provided with an inert gas outlet and a central stirring shaft; the insertion opening position (A) of the inert gas inlet pipe and the inert gas outlet position (B) on the surface of the upper head form an angle α (∠ACB) with the fixed position (C) of the central stirring shaft projected onto the plane on the upper head surface, where 30°≤α≤180°. The present application can achieve stable catalytic activity of a catalyst by means of controlling the use of nitrogen during the reaction process, which is conducive to stable process control, resulting in a low color number and reduced amine odor in the obtained product.