Method for synthesizing hexamethylene diisocyanate (HDI) biuret

A technology of hexamethylene diisocyanate and biuret is applied in the field of synthesizing hexamethylene diisocyanate biuret by spray method, and the effect of reducing HDI content, generation and use toxicity is achieved

Inactive Publication Date: 2009-07-08
JIANGMEN YIYUAN BIOCHEM ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The dripping method is commonly used for the reaction of HDI and water, and the method of res

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Add 30 mol of hexamethylene diisocyanate (HDI) into the reaction kettle, stir and heat up to 99°C; pressurize 5 mol of water and spray it into the reaction kettle through the nozzle in the form of mist, spray it in 2 hours, and heat up to 130°C, keep warm for 2 hours, and filter the mixture through a 200-mesh filter cloth. After filtration, it undergoes one-stage separation. The separation device adopts an internal cooling thin film evaporator. The separation temperature is 150°C and the separation pressure is 30Pa. After separation, the HDI biuret product is obtained. The free HDI mass content is 0.48%, and the NCO content is 20.6%. , solid content 99.5%.

Embodiment 2

[0021] Add 30 mol of hexamethylene diisocyanate (HDI) into the reaction kettle, stir and raise the temperature to 60°C. 15 mol of water is pressurized and sprayed into the reaction kettle through the nozzle in the form of mist, and the spraying is completed in 8 hours. After the spraying, it is kept at 80°C for 0 hours, and the mixed solution is filtered through a 200-mesh filter cloth. After filtration, it undergoes two-stage separation. Both stages of the two-stage separation device adopt internal cooling thin-film evaporators. The first-stage separation temperature is 70°C, the separation pressure is 1Pa, the second-stage separation temperature is 70°C, and the separation pressure is 0.5Pa. , HDI biuret product is obtained after separation, its free HDI mass content is 0.12%, NCO content is 19.8%, and solid content is 99.8%.

Embodiment 3

[0023] Add 30 mol of hexamethylene diisocyanate (HDI) into the reaction kettle, stir and raise the temperature to 60°C. 2 mol of water is pressurized and sprayed into the reaction kettle through the nozzle in the form of mist, and the spray is completed in 0.5 hours. After spraying, it is kept at 150°C for 5 hours, and the mixed solution is filtered through a 200-mesh filter cloth. After filtration, it undergoes two-stage separation. The first stage of the two-stage separation device uses an internal cooling thin film evaporator, and the second stage uses a centrifugal molecular still. The first stage separation temperature is 200 ° C, the separation pressure is 50000 Pa, and the second stage separation temperature is 200°C, separation pressure at 5000Pa, HDI biuret product is obtained after separation, diluted with ethyl acetate, its free HDI mass content is 0.15%, NCO content is 16.7%, and solid content is 80.1%.

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Abstract

The invention relates to a method for synthesizing hexamethylene diisocyanate (HDI) biuret through a spray method. The method comprises the following steps: adopting the high pressure to inject water in the form of fog drops into an HDI contained reaction kettle, setting the temperature to be between 60 and 130 DEG C, setting the mol ratio of HDI to water 2 to 15, setting the water spraying time to be between 0.5 and 8 hours, carrying out heat preservation at a temperature of between 80 and 150 DEG C for 0 to 5 hours, and then carrying out the separation through a separating device; setting the separation temperature to be between 70 and 200 DEG C and the pressure to be between 0.5 and 50,000Pa; and pumping the separated steaming residue into a dilution container with a stirrer for dissolution, adding a metered solvent into the dilution container in advance, continuously adding the metered solvent into the dilution container with the pumping of the steaming residue, and carrying out the dilution to obtain an HDI biuret product with 25 to 100 percent of solid content. The method improves the reaction efficiency for producing the HDI biuret product, reduces the generation of polyurea, reduces the HDI content in the HDI biuret, and reduces the use toxicity of the HDI biuret. In addition, the production process is economical and has environmental protection.

Description

technical field [0001] The invention relates to a reaction method of a high-viscosity heat-sensitive easily curable polymer, in particular to a method for synthesizing hexamethylene diisocyanate (HDI) biuret by spraying. Background technique [0002] Hexamethylene diisocyanate biuret, referred to as HDI biuret, is one of the best anti-aging properties among all polyurethane curing agents, and is suitable for crosslinking agents in various materials. Such as coatings, adhesives, leather, polyurethane rubber, polyurethane elastomer, etc. The synthesis and separation of HDI biuret must solve three technical problems: one is to improve the reaction efficiency and reduce the generation of polyurea; the other is to reduce the HDI content in HDI biuret and reduce the toxicity of HDI biuret; the third is the process Both economical and environmentally friendly. [0003] At present, my country is still unable to produce HDI biuret, and there are few domestic research reports. At p...

Claims

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Application Information

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IPC IPC(8): C08G18/79C07C265/14C07C263/18
Inventor 胡孝勇
Owner JIANGMEN YIYUAN BIOCHEM ENG
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