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Stabilizing treatment method for polyformaldehyde

A technology for stabilizing polyoxymethylene, which is applied in the field of stabilizing polyoxymethylene with a screw extruder, can solve the problems of unstable end groups, uneven distribution of additives, appearance performance, heat resistance and environmental protection performance. Improvement and other issues to achieve the effect of improving uniformity and appearance performance

Active Publication Date: 2013-06-12
CHNA ENERGY INVESTMENT CORP LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method results in uneven distribution of the additive in the polymer
CN101273073A discloses a method for preparing polyoxymethylene or polyoxymethylene, in which the prepared polymer and general auxiliary agents are entered into an extruder for melt blending and extrusion, but the method of adding auxiliary agents is not mentioned
[0007] In the above method, the unstable polyoxymethylene powder with unstable end groups is used to directly pre-mix with compounding additives and then melt extrude, or to add to the extruder at the same time and melt extrude, so that the obtained polyoxymethylene has a high appearance. Performance, heat resistance, environmental performance and other aspects still need to be improved

Method used

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  • Stabilizing treatment method for polyformaldehyde
  • Stabilizing treatment method for polyformaldehyde
  • Stabilizing treatment method for polyformaldehyde

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0059] Preparation of compound additives:

[0060] ①With 186g aldehyde absorbent melamine, 546g antioxidant triethylene glycol bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], 268g lubricant ethylene bisstearate Add the amide into a 3L high-speed mixer, and mix evenly at a speed of 3000 rpm;

[0061] ②Put the uniformly mixed additives into the extrusion molding machine, extrude and pelletize to obtain long compound additives;

[0062] ③Put the granulated composite additives into the crusher for crushing, and finally obtain granular composite additives with a particle size of 0.65-0.85 mm.

[0063] POM stabilization treatment:

[0064] Grind 2.95kg of polyoxymethylene pellets with stable end groups into a powder with a particle size of 0.58-0.94mm through a mill, then mix the powder with 213g of compound additives in a mixer, and mix with 27.04 kg polyoxymethylene powder with unstable end groups from the polymerization reactor (the molecular chain is not terminated...

Embodiment 2

[0067] Preparation of compound additives:

[0068] ①With 175g aldehyde absorbent melamine, 563g antioxidant triethylene glycol bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], 218g lubricant ethylene bisstearate Add the amide into a 3L high-speed mixer, and mix evenly at a speed of 3000 rpm;

[0069] ② Add 284g of ethanol to the compounding additive and mix evenly, then add the compounding additive into the extrusion molding machine, extrude and pelletize to obtain a strip-shaped compounding additive;

[0070] ③Dry the granulated compound auxiliary agent and put it into a crusher for crushing, finally obtain a granular compound auxiliary agent with a particle size of 0.58-0.85 mm.

[0071] POM stabilization treatment:

[0072] Mix 3.05kg of polyoxymethylene powder with stable end groups (particle size: 0.54-0.89mm) and 215g of composite additives in the mixer after being pulverized by a mill, and then mix them with 26.95kg of polyoxymethylene powder from the polyme...

Embodiment 3

[0075] Preparation of compound additives:

[0076] ① Mix 182g aldehyde absorbent melamine formal, 538g antioxidant N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyphenylpropanamide), 271g lubricant ethylene bisoleic acid Add the amide into a 3L high-speed mixer, and mix evenly at a speed of 3000 rpm;

[0077] ②Put the uniformly mixed additives into the extrusion molding machine, extrude and pelletize to obtain long compound additives;

[0078] ③Put the granulated composite additives into the crusher for crushing, and finally obtain granular composite additives with a particle size of 0.59-0.83 mm.

[0079] POM stabilization treatment:

[0080]Mix 2.98kg of polyoxymethylene powder (particle size: 0.53-0.91mm) and 211g of composite additives in a mixer with stable end groups after being pulverized by a pulverizer, and then mix them with 26.98kg of polyoxymethylene powder from a polymerization reactor. The polyoxymethylene powder with unstable end groups (molecular chain is n...

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Abstract

The invention discloses a stabilizing treatment method for polyformaldehyde. The method comprises the following steps: (1) uniformly mixing polyformaldehyde having a stable end group with a composite auxiliary agent to form a premix; and (2) uniformly mixing the premix with polyformaldehyde having an instable end group in a screw extruder and converting polyformaldehyde having the instable end group into polyformaldehyde having the stable end group through fused termination in the screw extruder; wherein the composite auxiliary agent comprises an aldehyde absorbing agent, an anti-oxidant and a lubricant. With the method provided by the invention, uniformity of dispersion of the auxiliary agent in polyformaldehyde can be improved; furthermore, appearance performance, heat resistance and environmental protection performance (e.g., aldehyde content on the surface of polyformaldehyde is reduced) of a product can be improved.

Description

technical field [0001] The invention relates to a method for stabilizing polyoxymethylene, in particular to a method for stabilizing polyoxymethylene with a screw extruder. Background technique [0002] Polyoxymethylene resin has a regular molecular structure and high crystallinity, so it has high tensile strength, high flexural modulus, high hardness, and excellent comprehensive performance. It is widely used in the fields of automobiles, electronics, office equipment, mechanical engineering and household devices. Polyoxymethylene resin plays a very important role in the preparation of various rotating parts (eg, gears, bearings) and the like. [0003] Polyoxymethylene usually uses paraformaldehyde as the main monomer, and dioxolane, dioxepane, ethylene oxide, propylene oxide, etc. as comonomers. Boron ether complex, cation exchange resin, ionic liquid, perchloric acid and other reagents that can provide cationic active centers are polymerized. During the polymerization p...

Claims

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Application Information

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IPC IPC(8): B29C47/38B29C47/92C08L59/00B29C48/395B29C48/49B29C48/92
CPCB29C47/6031B29C47/369B29C47/362B29C47/56B29C47/6037B29C48/362B29C48/39B29C48/49B29C48/54B29C48/55
Inventor 方伟罗春桃袁炜赵建宁李虎张彩霞申宏鹏姜慧婧余中云孙亚楠黄河张维
Owner CHNA ENERGY INVESTMENT CORP LTD
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