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Method for preparing binded NdFeB in-situ after injection moulding forming

An in-situ polymerization and injection molding technology, applied in the direction of magnetic objects, magnetic materials, inorganic materials, etc., can solve the problems of complex process, low bonding strength, uniformity effect of mixing magnetic powder and binder, etc., to simplify The effect of forming process, ensuring sufficient and uniform mixing, and saving investment in granulation equipment

Inactive Publication Date: 2006-06-07
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] There are following deficiencies in the prior art: (1) prior art adopts NdFeB magnetic powder through surface treatment and polyamide (nylon), lubricant, antioxidant are mixed in a high-speed mixer in a certain proportion, and then in twin-screw ( (single-screw) in the extruder for melt extrusion, granulation, and then injection molding in the injection molding machine. The density is 7.64g/cm 3 , the density of nylon is 1.11g/cm 3 , due to

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0025] Example one

[0026] In the first step, in terms of parts by mass, mix 1 part of KH550 and 99 parts of NdFeB magnetic powder uniformly, and then fully dry to coat the surface of the NdFeB magnetic powder;

[0027] In the second step, the caprolactam monomer (CL) is heated to 80°C and melted into a liquid, and then vacuumed to 1×10 -1 Pa in addition to water for 30 minutes;

[0028] The third step is to add 0.15 parts of antioxidant Irganox 1098 and 5 parts of hexamethylphosphoric triamide to 100 parts of the caprolactam melt prepared in the second step under the condition of 0.2Pa high purity nitrogen. (HPT), 2 parts of calcium stearate to make a monomer solution; mix 7 parts of the monomer solution with 93 parts of NdFeB magnetic powder prepared in the first step, stir thoroughly to obtain a mixed system; in 100 parts of a mixed system Add 0.5 parts of toluene diisocyanate (TDI) and 0.8 parts of potassium hydroxide, stir evenly and heat to 150°C and keep it for 5 minutes t...

Example Embodiment

[0030] Example two

[0031] In the first step, in terms of parts by mass, 3 parts of KH550 and 93 parts of NdFeB magnetic powder are mixed uniformly and fully dried to coat the surface of the magnetic powder;

[0032] In the second step, the caprolactam monomer (CL) is heated to 60°C and melted into liquid, and then vacuumed to 1×10 -4 Remove water for 10 minutes;

[0033] In the third step, under the condition of 0.6Pa high-purity nitrogen, add 0.1 part of antioxidant Irganox 1098 and 7 parts of hexamethylphosphoric triamide to 100 parts of the caprolactam melt prepared in the second step by mass parts. (HPT), 1 part of zinc stearate to make a monomer solution; mix 10 parts of the monomer solution with 90 parts of NdFeB magnetic powder prepared in the first step, stir thoroughly to obtain a mixed system; in 100 parts of a mixed system Add 0.3 parts of toluene diisocyanate (TDI) and 0.5 parts of potassium hydroxide, stir evenly and heat to 140°C and keep it for 3 minutes to prepar...

Example Embodiment

[0035] Example three

[0036] In the first step, in terms of parts by mass, mix 5 parts of KH 550 and 95 parts of NdFeB magnetic powder uniformly and then fully dry it to coat the surface of the magnetic powder;

[0037] In the second step, the caprolactam monomer (CL) is heated to 70°C and melted into a liquid, and then vacuumed to 1×10 -3 Remove water for 15 minutes;

[0038] In the third step, under the condition of 0.4Pa high-purity nitrogen; in parts by mass, add 0.3 parts of antioxidant Irganox 1098 and 10 parts of hexamethylphosphoryl three to 100 parts of the caprolactam melt prepared in the second step Amine (HPT) and 0.5 parts of barium stearate are made into a monomer solution; 15 parts of the monomer solution are mixed with 85 parts of the NdFeB magnetic powder prepared in the first step, and the mixture is fully stirred to obtain a mixed system; in 100 parts of the mixed system Add 0.1 part of toluene diisocyanate (TDI) and 0.2 part of potassium hydroxide, stir evenly, ...

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Abstract

This invention discloses a method for preparing felt NdFeB magnet by in-situ polymerization after formation by injection, which adds coated NdFeB powder into caprolactam monomer solution to prepare a medium reactor to be injected into a model cavity by a double or single screw extruder to form a polymer binder on the magnetic powder surface by in-situ polymerization, which finishes the mixing of the binder of magnetic powder and the formation of the magnet at one run to save the process of sizing and re-heating the size material and generates a polymer as the binder on the surface of a magnet powder to coat a polymer on the surface of each powder uniformly to bind the powder and the binder reliably.

Description

technical field [0001] The invention relates to the technical field of magnet forming and processing, in particular to preparing bonded NdFeB magnets by in-situ polymerization after injection molding. Background technique [0002] Bonded NdFeB magnet is produced by mixing NdFeB magnetic powder prepared by quick quenching method or HDDR method with resin or polymer material, and then preparing it into final size and shape by molding, injection molding, calendering, etc. Bonded magnets have been widely used in industry, agriculture, Military, science and technology, medicine, and all aspects of life, such as small precision motors, stepping motors, and spindle motors for hard disk drives that are widely used. Among them, the application of bonded NdFeB magnets in rotating devices (mainly micromotors for computers) is the largest, accounting for 94% of the total output. [0003] The injection molding bonded permanent magnet process is to mix permanent magn...

Claims

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Application Information

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IPC IPC(8): H01F1/08H01F1/057H01F41/02
Inventor 车晓舟
Owner SOUTH CHINA UNIV OF TECH