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Preparation method of polyisocyanate

A technology of polyisocyanate and base isocyanate is applied in the field of preparation of polyisocyanate, and can solve the problems such as adverse effect, influence and increase of operating cost of product turbidity.

Active Publication Date: 2021-07-06
WANHUA CHEM GRP CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In practice, such gel particles will inevitably have an adverse effect on the turbidity of the product because they are heterogeneous with the product.
[0006] Therefore, in today's polyisocyanate production process, more emphasis is placed on how to reduce the turbidity of polyisocyanate while ignoring the change in turbidity of polyisocyanate during storage. As the storage time increases, the turbidity of polyisocyanate will gradually decrease. Increase, adversely affect downstream products
Although the turbidity in polyisocyanate can be reduced by filtering equipment, it also greatly increases the operating cost
Therefore, a new method needs to be sought to solve the problem of turbidity stability in existing polyisocyanate products

Method used

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  • Preparation method of polyisocyanate
  • Preparation method of polyisocyanate
  • Preparation method of polyisocyanate

Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0032] The preparation method of polyisocyanate can refer to the method similar to Example 4 on page 20 of patent CN 1509302 A.

[0033] The measurement of the turbidity of the polyisocyanate uses an American Hach 2100N turbidimeter.

[0034] The above methods are common knowledge in the technical field, and will not be described in detail one by one.

Embodiment 1

[0037] Mix 600kg / h of 1,6-hexamethylenediamine raw material with nitrogen medium and then gasify it, then feed the gasified 1,6-hexamethylenediamine, nitrogen and phosgene into the reaction zone for phosgene The average contact time of 1,6-hexanediamine and phosgene in the reaction zone is 5s, the phosgene contains 5wt% HCl gas, and the volume ratio of nitrogen to 1,6-hexanediamine gas is 0.1:1. The molar ratio of phosgene and 1,6-hexanediamine is 6:1, the temperature of the reaction zone is 350°C, the absolute pressure of the reaction zone is 0.09MPa, and the feed stream of 1,6-hexanediamine and phosgene enters the reaction The flow velocity in the zone is 10m / s, and the Reynolds number of the reaction mixture stream is 4000; after the reaction, the reactant is sprayed and washed with chlorobenzene to cool it to 100°C. The upstream of the above-mentioned reaction zone is adjacent to the raw material delivery pipe, and the downstream is adjacent to the gas phase reaction produc...

Embodiment 2

[0039] Mix 300kg / h of 1,6-hexamethylenediamine raw material with nitrogen medium and then gasify it, then feed the gasified 1,6-hexamethylenediamine, nitrogen and phosgene into the reaction zone together for phosgene The average contact time of 1,6-hexanediamine and phosgene in the reaction zone is 10s, the phosgene contains 10wt% HCl gas, and the volume ratio of nitrogen to 1,6-hexanediamine gas is 1:1. The molar ratio of phosgene and 1,6-hexanediamine is 8:1, the temperature of the reaction zone is 450°C, the absolute pressure of the reaction zone is 0.18MPa, and the feed stream of 1,6-hexanediamine and phosgene enters the reaction The flow velocity in the zone is 80m / s, and the Reynolds number of the reaction mixture stream is 5000; after the reaction, the reactant is sprayed and washed with chlorobenzene to cool it to 90°C. The upstream of the above-mentioned reaction zone is adjacent to the raw material delivery pipe, and the downstream is adjacent to the gas phase reactio...

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PUM

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Abstract

The invention discloses a preparation method of polyisocyanate. The method comprises the following steps: carrying out a phosgenation reaction on 1, 6-hexanediamine and phosgene to obtain 1, 6-hexamethylene diisocyanate containing a difficult-to-separate component A, and rectifying the 1, 6-hexamethylene diisocyanate to enable the content of the difficult-to-separate component A to be less than or equal to 60 mg / kg, wherein when the rectified 1, 6-hexamethylene diisocyanate is used as a monomer raw material to synthesize polyisocyanate, compared with an existing product, the polyisocyanate has the characteristic of relatively stable turbidity, and the turbidity change is small in the storage process.

Description

technical field [0001] The invention belongs to the technical field of polyisocyanate preparation, in particular to a preparation method of polyisocyanate with relatively stable turbidity. Background technique [0002] The corresponding isocyanates can be prepared by gas-phase phosgenation of aliphatic or aromatic amines, which can be carried out particularly advantageously in the gas phase. But frequently the problem arises that, for whatever reason, these isocyanates are turbid or undergo undesired side reactions in later modification steps, such as prepolymerization, formation of biurets or trimers, and have negative effects on the resulting The turbidity of the polyisocyanate is adversely affected. The causes and sources of this turbidity are various and not all impurities in the isocyanate inevitably lead to undesired turbidity changes in the immediate process product or downstream products. [0003] U.S. Patent No. 5,691,440 describes a method for preparing HDI trime...

Claims

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Application Information

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IPC IPC(8): C07D251/34
CPCC07D251/34
Inventor 李强李同和孙淑常王京旭尚永华王鹏飞李建峰石滨韩金平孙立东
Owner WANHUA CHEM GRP CO LTD