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Method of preparing hexamethylene diisocyanate biuret through water vapor method

A technology of hexamethylene diisocyanate and water vapor, which is applied in the preparation of urea derivatives, chemical instruments and methods, and the preparation of organic compounds, and can solve the problem of free hexamethylene diisocyanate monomers and products with high chroma. Solve problems such as low chroma, achieve good economic and environmental benefits, good storage stability, and low chroma

Inactive Publication Date: 2016-02-24
QINGDAO UNIV OF SCI & TECH +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0015] The invention provides a method for preparing hexamethylene diisocyanate biuret by a steam method, so as to solve the problem of producing a large amount of white polyurea substances in the existing technology of synthesizing HDI biuret, the chroma of the product is high, and the chroma of the product is high. For the problem of remaining free hexamethylene diisocyanate monomers, the present invention can basically suppress the formation of insoluble polyurea during the reaction, the product has low chroma, and the free HDI content in the product reaches the standard after the reaction and separation of the monomers

Method used

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  • Method of preparing hexamethylene diisocyanate biuret through water vapor method
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  • Method of preparing hexamethylene diisocyanate biuret through water vapor method

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Effect test

Embodiment 1

[0042] 40kg of HDI was added to the reactor, and the temperature of the reactor was raised to 98°C. The molar ratio of HDI to water vapor was 5:1, and the volume flow rate of nitrogen and water vapor was mixed at 1:1. After dilution, the water vapor was evenly added to the reactor within 2 hours. After the addition, the reactor was kept warm for 0.5 hours, the temperature of the reactor was raised to 130° C., and the reaction was continued for 3 hours to obtain the crude product of HDI biuret. The crude product of HDI biuret passes through a filter to remove a little solid impurity, and is separated by a thin-film evaporator. The operating temperature is 160°C and the pressure is 20Pa. After separation and removal, the finished HDI biuret product is obtained. The free HDI mass content is 0.45%, and the NCO content is 21.8%, biuret group content 46.2%.

Embodiment 2

[0044]40kg of HDI was added to the reactor, and the temperature of the reactor was raised to 98°C. The molar ratio of HDI to water vapor was 5:1, and the volume flow rate of nitrogen and water vapor was mixed at 1:1. After dilution, the water vapor was evenly added to the reactor within 2 hours. After the addition, the reactor was kept warm for 0.5 hours, then the temperature of the reactor was raised to 120°C, and the reaction was continued for 3 hours to obtain the crude product of HDI biuret. The crude product of HDI biuret passes through a filter to remove a little solid impurity, and is separated by a thin-film evaporator. The operating temperature is 160°C and the pressure is 20Pa. After separation and removal, the finished HDI biuret product is obtained. The free HDI mass content is 0.52%, and the NCO content is 22.1%, biuret group content 45.7%.

Embodiment 3

[0046] 40kg of HDI was added to the reactor, and the temperature of the reactor was raised to 98°C. The molar ratio of HDI to water vapor was 5:1, and the volume flow rate of nitrogen and water vapor was mixed at 1:1. After dilution, the water vapor was evenly added to the reactor within 3 hours. After the addition, the reactor was kept warm for 0.5 hours, and the temperature of the reactor was raised to 130° C., and then reacted for 3 hours to obtain the crude product of HDI biuret. The crude product of HDI biuret passes through a filter to remove a little solid impurity, and is separated by a thin-film evaporator. The operating temperature is 160°C and the pressure is 20Pa. After separation and removal, the finished HDI biuret product is obtained. The free HDI mass content is 0.61%, and the NCO content is 21.3%, biuret group content 44.9%.

[0047] In the above examples, the percentage content of NCO groups is detected by di-n-butylamine titration; the content of free HDI mo...

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Abstract

The invention relates to a method of preparing hexamethylene diisocyanate biuret through a water vapor method. According to the method, water vapor diluted with inertial material flow and hexamethylene diisocyanate (HDI) are subjected to a reaction at the temperature between 80 DEG C and 140 DEG C, and a filter is used for removing a small quantity of white polyurea particles generated in the reaction process; a film evaporator is adopted to separate free HDI monomers remaining in the product, a gas chromatograph is used for determining the content of free HDI in the product, infrared spectrum detection and gel permeation chromatography detection are used for judging whether biuret is generated or not and the content of the biuret relative to other components.

Description

technical field [0001] The present invention relates to a method for preparing a non-yellowing highly decorative polyurethane coating, in particular to a method for preparing hexamethylene diisocyanate biuret from hexamethylene diisocyanate using water vapor as a biuretization agent . Background technique [0002] Although my country's polyurethane coatings have developed greatly in recent years, with more varieties and wider uses, they are basically aromatic polyurethane coatings, while most of the aliphatic polyisocyanates needed in my country come from abroad. It has excellent weather resistance and will not turn yellow after long-term sunlight. It is mostly used in high-end applications, such as train paint, aircraft paint, large passenger car paint, building exterior walls, and upper layer paint on offshore platforms. As the earliest high-performance two-component polyurethane coating curing agent, HDI biuret has played a vital role in the development and application of...

Claims

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Application Information

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IPC IPC(8): C08G18/79C07C273/18C07C275/62
CPCC07C273/18C08G18/792C07C275/62
Inventor 杨霞钟洁水徐进付振波郑世清
Owner QINGDAO UNIV OF SCI & TECH
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