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A kind of polymethylene polyphenyl polyisocyanate composition and preparation method thereof

A technology of polymethylene polyphenyl and polyisocyanate, which is applied in the field of preparing polymethylene polyphenyl polyisocyanate, and can solve problems such as difficult operation, high operation and equipment costs, and complicated process flow

Active Publication Date: 2022-07-12
WANHUA CHEM GRP CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The same DE1107218 and SU1811161 both absorb phosgene in HCl by using different solvents, but the disadvantage is also obvious, part of the solvent will be entrained in the HCl gas flow after absorption
[0012] The published patents DE2143994 and GB737442 have also proposed methods for separating HCl and phosgene by means of condensation, but both require a lower temperature to control the phosgene content in HCl at a lower level, so the operation and equipment costs are relatively high. complicated maintenance
[0013] Although the separation of HCl and phosgene in the above patents also has a certain removal effect on MDI and PI in HCl, especially the method of solvent absorption, there are certain shortcomings, such as high energy consumption, high operating costs, and complicated process flow. Difficult to operate etc.

Method used

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  • A kind of polymethylene polyphenyl polyisocyanate composition and preparation method thereof
  • A kind of polymethylene polyphenyl polyisocyanate composition and preparation method thereof
  • A kind of polymethylene polyphenyl polyisocyanate composition and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0078] Take 100g of N,N-dimethylformamide, add 100g of polyimide, mix and dissolve completely, add 3g of SiC and 0.3g of Pd nanoparticles to the polyimide solution to obtain a mixed solution, and then rotate the mixed solution by rotating The coating instrument is evenly coated on the treated ceramic substrate. The ceramic substrate should be polished and solvent cleaned before use, and dried for use. Then place the ceramic substrate in the oven, set a gradient heating program, start from room temperature, first heat up to 80 °C for 1 hour, and then program the temperature to 300 °C after 200 minutes, and keep the temperature for 2 hours, and then the ceramic substrate is finished. Place in boiling water to remove the membrane.

[0079] The obtained polyimide composite carbon film was trimmed neatly and placed in two stacked quartz sheets, and then placed in a vacuum tube sintering furnace, and nitrogen gas was introduced into the vacuum tube sintering furnace, and the nitroge...

Embodiment 2

[0081] Take 100g of N,N-dimethylformamide, add 100g of polyimide to completely mix and dissolve, add 2g of SiC and 0.1g of Pd nanoparticles to the polyimide solution to obtain a mixed solution, and then rotate the mixed solution by rotating The coating instrument is evenly coated on the treated ceramic substrate. The ceramic substrate should be polished and solvent cleaned before use, and dried for use. Then place the ceramic substrate in the oven, set the gradient heating program, start from room temperature, first heat up to 60 °C for 2 hours, and then program the temperature to 250 °C after 150 minutes, and keep the temperature for 3 hours, and then heat the ceramic substrate after the end. Place in boiling water to remove the membrane.

[0082] The obtained polyimide composite carbon film was trimmed neatly and placed in two stacked quartz sheets, and then placed in a vacuum tube sintering furnace, and nitrogen gas was introduced into the vacuum tube sintering furnace, and...

Embodiment 3

[0087] use figure 1 As shown in the process flow, the prepared reaction solution is passed to the bottom of the dephosgenation tower A, and heat treated under normal pressure and 140 ° C for 1 h, and the phosgene content in the treated reaction solution 2 is reduced to below 100ppm . Then the dephosgenated reaction solution 2 is sent to the top of the HCl stripper B. The top gas stream 3 of the dephosgenation tower A mainly contains phosgene, HCl and solvent.

[0088] The HCl gas flow 4 containing 10,000 ppm of the material that affects the phosgene adduct content is sent to the membrane separation device C, and the HCl gas flow pressure is 3 bar (gauge pressure), and the selected membrane separation unit contains 3 separation blocks, which are prepared in Example 1. Polyimide composite carbon membrane, after 3-stage membrane separation, the purified HCl gas flow 7 enters the gas-liquid separation tank D1, and the gas phase 8 above the gas-liquid separation tank D1 enters th...

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Abstract

The invention provides a polymethylene polyphenyl polyisocyanate composition and a preparation method thereof. The HCl stripping process is adopted in the preparation process, and by controlling impurities in HCl (including COCl 2 , PI (phenyl isocyanate), MDI (diphenylmethane series diisocyanate) these substances that potentially affect the content of phosgene adduct) can effectively control the content of phosgene adduct in the reaction solution after HCl stripping, improve the Curing rate of polymethylene polyphenyl polyisocyanate composition production process, and compressive strength of foam after foaming with polyether. Moreover, the HCl stripping process is simple, the operation cost is low, the operation is convenient, and has certain effects on improving the production efficiency of the product and improving the application performance of the product.

Description

technical field [0001] The invention belongs to the field of isocyanate production, and relates to a method for preparing polymethylene polyphenyl polyisocyanate (methylene cross-linked polyphenylmethane polyisocyanate). Background technique [0002] Polymethylene polyphenyl polyisocyanate is mainly used in the production of polyurethane rigid foam, mainly used in home appliances, and other cold storage, containers, building insulation materials, etc. In the existing poly-MDI application process, the mechanical properties of the foam after foaming are poor, especially the compressive strength of the rigid foam is low, which cannot meet the application requirements. [0003] The production of polymethylene polyphenyl polyisocyanates is well known in the art. The main industrial preparation method is as follows: in the presence of a solvent, aniline and formaldehyde are condensed to form a polyamine mixture, the polyamine mixture is further reacted with phosgene to generate a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C263/10C07C263/00C07C263/18C08G101/00
CPCC08G18/7664C08G18/7812C08G18/725C08G18/48B01D71/021B01D71/022B01D71/02B01D69/02B01D69/12B01D67/0039B01D67/0067B01D53/228C08G2101/00
Inventor 黄荐文放赵东科张宏科吴雪峰
Owner WANHUA CHEM GRP CO LTD
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