Biuret Polyisocyanate Production via Two-Stage Continuous Addition
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Solution Overview
Problem
The existing diisocyanate/diamine process for producing polyisocyanates with a biuret structure faces challenges such as high energy consumption, temperature-related damage to reactants, and limitations in mixing conditions during load and product changes, leading to inefficient production and increased by-product formation.
Innovation Solution
A two-stage continuous process where the first stage involves mixing isocyanate and amine components at temperatures above 170 °C, followed by the addition of a second isocyanate component at 20 to 250 °C, with a controlled ratio of isocyanate to amine, reducing thermal stress and energy requirements while maintaining optimal mixing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the diisocyanate/diamine process is used to produce polyisocyanates with biuret structure, then production economy and quality are improved, but energy consumption increases due to high temperature heating requirements
Solution Approach 1:
The continuous production process is divided into two distinct stages: first stage involves mixing isocyanate and amine components at temperatures above 170°C to form initial reaction products, while the second stage adds a second isocyanate component at 20 to 250°C to complete the biuret formation. This segmentation allows each stage to operate at optimized temperatures, reducing overall energy consumption while maintaining production economy and quality.
2Speed
If high temperatures are used to ensure rapid reaction and biuret formation, then reaction speed is improved, but temperature-related damage to reactants increases
Solution Approach 1:
The reaction process is segmented into two stages with different temperature profiles. The first stage uses temperatures above 170°C to initiate rapid reaction and biuret formation. The second stage adds isocyanate component at 20 to 250°C to complete the reaction. This segmentation ensures rapid reaction while limiting maximum temperature exposure, reducing temperature-related damage to temperature-sensitive reactants.
Solution Approach 2:
The first stage performs preliminary reaction and biuret formation at controlled temperatures above 170°C before introducing the second isocyanate component in the second stage. This preliminary action establishes the reaction foundation under optimized conditions, reducing the need for excessive temperature elevation in subsequent stages and minimizing thermal damage to reactants.
3Manufacturing precision
If mixing chamber/nozzle systems are designed for narrow flow range to ensure optimal mixing, then mixing quality is improved, but adaptability to load and product changes decreases
Solution Approach 1:
The mixing system incorporates adjustable flow ratios between the two stages. The first stage handles a certain proportion of isocyanate flow, while the second stage adds the remaining proportion. This dynamic adjustment capability allows the system to adapt to varying load and product requirements while maintaining optimal mixing conditions through controlled staged addition, resolving the contradiction between fixed narrow flow range and adaptability.
4Device complexity
If the isocyanate component is added in a single stage, then process simplicity is improved, but by-product formation increases due to suboptimal mixing conditions during changes
Solution Approach 1:
The single-stage addition process is segmented into two sequential stages: first stage mixes isocyanate and amine components at temperatures above 170°C, then the second stage adds the remaining isocyanate component at 20 to 250°C. This segmentation maintains relative process simplicity while significantly reducing by-product formation by ensuring optimal mixing conditions are maintained throughout load and product changes, as each stage can be independently optimized for the specific reaction requirements.
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
This approach results in high-quality polyisocyanates with reduced by-product formation and energy consumption, allowing for consistent production without sacrificing the advantages of the diisocyanate/diamine process, and achieving the desired viscosity and NCO content.
Implementation Method 1
reacting excess amounts of organic isocyanates with exclusively aliphatically and/or cycloaliphatically bound isocyanate groups (A) with organic amines with exclusively aliphatically and/or cycloaliphatically bound primary amino groups (B)
Implementation Method 2
the temperature being kept above 170 °C
Data Source
AI summary
The present invention relates to an improved process for the production of polyisocyanates with a biuret structure by continuous reaction of excess amounts of organic diisocyanates with exclusively aliphatic and/or cycloaliphatic bonded isocyanate groups with organic diamines with exclusively aliphatic and/or cycloaliphatic bonded primary amino groups at elevated temperatures by 2-stage addition of the isocyanate component.