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A kind of method of polyoxymethylene copolymer semi-dry post-treatment

A kind of copolyformaldehyde and semi-dry technology, which is applied in the field of post-treatment process of copolyformaldehyde, can solve the problems of short process flow, poor economy, low efficiency and the like

Active Publication Date: 2021-03-02
TANGSHAN KAILUAN CHEM TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method solves the problems of poor economy and low efficiency of the post-treatment process of polyformaldehyde, and effectively provides a short process flow, green and efficient post-treatment method of polyformaldehyde

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Use 0.2MPa saturated water vapor at a temperature of 120°C and a flow rate of 500kg / min to pass into the steam distributor at the bottom of the drying tower. The working temperature of the drying tower is 140°C, the material level of acetal copolymer in the tower is 50kg, that is, the ratio of the mass of vapor per minute to the mass of acetal copolymer sample is 10, and the powder of acetal copolymer is continuously fed into the drying tower at a speed of 10kg / min, and passes through the bottom of the tower The rotary valve discharges continuously at a speed of 10kg / min and enters the raw material bin. The post-treatment reaction time of the copolymerized formaldehyde powder in the drying tower is 5 minutes (the ratio of the material level in the drying tower to the output speed). The working pressure at the top of the drying tower is 0.1MPa, and the steam is discharged from the top gas pipeline.

[0017] Table 1 Changes in properties of acetal copolymer powder before...

Embodiment 2

[0020] Use 0.6MPa, 160°C containing 20% ​​v / v ammonia-containing water vapor, with a flow rate of 25kg / min, to pass into the steam distribution bubbling orifice plate at the bottom of the horizontal twin-shaft paddle dryer. The barrel and screw temperature of the horizontal twin-shaft paddle dryer is 140°C, and the polyoxymethylene particles are continuously added to the feeding end of the horizontal twin-shaft paddle dryer at a speed of 50kg / min, and the angle of the overflow plate is adjusted to make the dryer The quality of the internal POM is 50kg, that is, the ratio of the vapor mass to the POM sample mass per minute is 0.5, and the conveying screw speed is adjusted to 30r / min, so that the POM particles are discharged at a speed of 50kg / min and enter the raw material bin. The sample post-treatment residence time is 1min (the mass ratio of acetal copolymer in the dryer to the output speed). The working pressure of the horizontal double-shaft paddle dryer is -0.01MPa, and t...

Embodiment 3

[0024] Heat the post-treatment reactor with a volume of 100 L to 120°C, add 50 kg of polyoxymethylene powder, and stir at a speed of 20 r / min. The working pressure of the post-treatment reactor is 0.6MPa. 0.6MPa, 160°C water vapor is continuously added to the bottom of the post-treatment reactor at a rate of 5kg / min, that is, the ratio of the mass of vapor per minute to the mass of acetal copolymer sample is 0.1. The post-treatment reactor was continuously reacted for 60 minutes at the temperature and pressure. The mixed steam is discharged from the top of the kettle through the pressure reducing valve. After the reaction is over, close the steam valve at the bottom of the post-processing reactor, and the polyoxymethylene powder is discharged from the discharge valve at the bottom of the kettle and enters the raw material warehouse.

[0025] Table 3 Changes in performance before and after post-treatment of polyoxymethylene powder reactor

[0026] sample M value / p...

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Abstract

The invention discloses a semi-dry post-treatment method of polyformaldehyde, which relates to the field of post-treatment technology of polyformaldehyde. By passing the steam of a certain temperature and pressure through the polyoxymethylene sample heated by the drying device and at the corresponding pressure according to the adapted flow rate, and maintaining a suitable reaction time, the unstable group in the polyoxymethylene sample is prompted to react with the steam, At the same time, use the mass transfer effect of steam to remove unreacted monomers, solvents and other volatile substances in the polyoxymethylene sample. This method utilizes the high reactivity and diffusivity in the vapor state of the substance to realize the post-treatment of the POM sample in the semi-dry state, significantly improves the efficiency and economy of the post-treatment process, and greatly improves the quality of the POM product.

Description

technical field [0001] The invention relates to the field of post-treatment technology of polyoxymethylene copolymer, in particular to a method for stabilizing and cleaning polyoxymethylene copolymer samples with reactive steam to realize high-efficiency and green preparation of high-quality polyoxymethylene copolymer products. [0002] technical background [0003] POM products can be divided into homopolyoxymethylene and copolymerized polyoxymethylene according to their different molecular structures. Polyoxymethylene is polymerized from trioxane and one or more comonomers. The addition of comonomers changed the molecular structure of polyoxymethylene and interrupted the sequence of methoxy repeating units, thereby changing the crystallization properties and thermal stability of polyoxymethylene. Copolyoxymethylene prepared by copolymerization has a large number of cationic active centers and unstable end groups in its molecular chain, which tends to continue to react and ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G2/28
CPCC08G2/28
Inventor 李建华马小丰刘莉莉金旺陈曦关礼争王亚涛杨大志
Owner TANGSHAN KAILUAN CHEM TECH CO LTD