WO2010031264A1

WO2010031264A1 - Anisotropic flexible bonded ndfeb magnet and manufacturing method of the same

Info

Publication number: WO2010031264A1
Application number: PCT/CN2009/072142
Authority: WO
Inventors: 戴雨兰; 汪小明; 杨应彬; 范保顺; 罗毅; 舒杰华; 利富贵
Original assignee: 广州金南磁塑有限公司
Priority date: 2008-09-19
Filing date: 2009-06-05
Publication date: 2010-03-25
Also published as: CN101477866A

Abstract

An anisotropic flexible bonded NdFeB magnet and a manufacturing method of the same. Anisotropic NdFeB magnetic powder, modified rubber-like binder, and working assistants are mixed uniformly in a weight ration of 87-97:1-8:0-5, and the obtained mixture is molded by compression, extrusion or injection into a flexible magnet with a certain thickness under magnetic field orientation. HDDR anisotropic NdFeB magnetic powder is used as the anisotropic NdFeB magnetic powder.

Description

The invention relates to an anisotropic flexible bonded rare earth permanent magnet material and a manufacturing method thereof, in particular to an anisotropic flexible bonded NdFeB magnet and a manufacturing method thereof

Background technique

The Nd ₂ Fe _i4 B-based NdFeB permanent magnets, which were introduced in the 1980s in the large family of permanent magnet materials, have the most disproportionate magnetic properties. Since the 1990s, with the computer-based information industry The strong demand for isotropic rigid bonded NdFeB magnets represented by quenched NdFeB is widely used.

In the past, the isotropic bonded NdFeB magnet processing method mostly uses hard plastic, resin, etc. as a binder and NdFeB magnetic powder after mixing and granulation, molding, injection molding or extrusion molding, and the obtained magnets are all sexual. , brittle, inflexible, 3⁄4 and the use of molding, injection molding process to produce different specifications of the product requires different molds, higher development costs, longer cycle „ while rigid magnets have higher magnetic properties and certain shape Degree of freedom, but there are shortcomings such as transportation and assembly inconvenience, and it is very difficult to make a magnet with an ultra-thin thickness (less than Ο.όπιηι) and an extra-large length (greater than 500 mm).

To this end, people have designed and developed a flexible bonded magnet, which is different from a rigid bonded magnet. It is made of rubber as a binder and is produced by a rubber processing process. It does not require a large amount of mold development cost, high production efficiency, and can be freely bent. Cracking, product size can be arbitrarily changed, thickness can be less than 0,6mm, easy for customers to assemble and use, has been widely used in home appliances, automobiles, In areas such as office automation, there is a large demand. However, in the existing large-scale production technology, most of the magnetic powders used are ferrites, and such ferrite bonded magnets have a certain anti-oxidation corrosion property and good mechanical properties, but the magnetic properties are low. In order to solve the above problems, the use of isotropic quenched NdFeB magnetic powder instead of ferrite can increase the maximum magnetic energy product of flexible magnets from 18 kJ/m ³ to 68 kJ/m ³ . This technique has been applied to applicants. It is disclosed in the patent ZL 20041 0052150.3. As the application field continues to demand ultra-thin, ultra-light, stable, high-power components, such as concert halls, squares, homes, etc., high-fidelity planar speakers that require larger areas, thinner thickness, and farther sounds; A thinner and more powerful fan motor is needed in laptops to meet the heat dissipation requirements of high-speed processing chips.: Faster, more torque direct-drive motors are needed in home appliances such as washing machines and fans; multimedia devices such as mobile phones, MP3, MP4, etc. Ultra-thin, ultra-light flexible sensors are required, and flexible bonded neodymium iron magnets can meet this usage requirement.

In recent years, with the urgent need for further thinning and high efficiency of information products, higher requirements have been placed on the performance of magnetic materials. Anisotropic NdFeB materials with higher permanent magnet properties have been researched and developed. Among them, the most successful method for preparing anisotropic NdFeB bonded magnetic powder is to adopt HDDR process (Hydrogenation-Hydrogenation, Disproporticmaticm-Disproportionation, Desorption-Dehydrogenation, Recon bhiatk-Recombination, referred to as HDDR current R&D and market focus They are all prepared by using HDDR anisotropic NdFeB magnetic powder as raw materials. [^-bonded magnets. According to the corresponding physical state, bonded magnets can be divided into rigid bonded magnets and flexible bonded magnets, different types of adhesives. The magnets are divided into molding, injection molding, extrusion, calendering, injection, etc. according to the molding method. In order to obtain a suitable magnet, the selection of raw materials is different when using different molding methods. Among them, the molded HDDR anisotropic rigidity The maximum magnetic energy product of the iron-boron bonded magnet is up to 200 kj/m ³ , which is more than twice the magnetic performance of the isotropic rigid NdFeB bonded magnet: The maximum magnetic energy product of plastic injection molded HDDR anisotropic rigid niobium-iron bonded magnets is also 125id/ni ³ , and no anisotropic flexible bonded NdFeB magnets have been produced at home and abroad.

Summary of the invention

The object of the present invention is to provide a new type of high performance anisotropic flexible bonded NdFeB magnet to meet the needs of high performance special motors, ultra-thin sensors, electroacoustic equipment and the like.

Another object of the present invention is to provide a method for manufacturing the above high performance anisotropic flexible bonded NdFeB magnet

The invention provides a high performance anisotropic flexible bonded NdFeB magnet whose composition and weight content are:

Anisotropic HDDR NdFeB magnetic powder 87-97%;

Modified rubber binder 1 -8%;

Processing aid ^ 0-5%

The magnetic powder used in the present invention is mainly an anisotropic HDDR neodymium iron boron (NdFeB) magnetic powder containing an essential component of Nd ₂ Fe ₁₄ B and is obtained by HDD treatment.

The magnetic properties of the magnet are positively correlated with the product of the square of the density of the magnetic powder and the degree of orientation. The particle size of the magnetic powder has an influence on the density and degree of orientation of the magnet. In the embodiment of the present invention, a magnetic powder having a particle diameter of 250 μm or less is preferably used, and a magnetic powder having a particle diameter of 75 to 180 μm is preferably used. At the same time, in order to obtain good processing fluidity, the particle size distribution of the magnetic powder is preferably in a dispersed state within a certain range. When the present invention is required, the anisotropic HDDR NdFeB magnetic powder may further contain a certain proportion of one or more of other rare earth permanent magnets or permanent magnet ferrite magnetic powder. The content of magnetic powder has an effect on the density and orientation of the magnet. The density is also increased when the amount of the material is increased, but the viscous resistance between the magnetic powder particles and the binder increases, the magnetic powder is difficult to rotate, and the degree of orientation is lowered. Therefore, the magnetic powder content is selected in consideration of both. In the embodiment of the present invention, the magnetic powder content is selected from 87 to 97 wt%, and in the more selected embodiment, 90-95 wt is selected.

The anisotropic HDDR neodymium iron boron magnetic powder is subjected to surface treatment according to the present invention; the surface treatment method is selected from the group consisting of organic or inorganic rubber coating, chemical or physical deposition plating, reverse passivation and a combination thereof.

Different polymer materials have different filling properties for inorganic materials due to cohesive energy, processing viscosity, density, etc. In the development of flexible rare earth magnets, how to select binders and modify binders It is a key task to achieve the highest possible magnetic powder filling property under the premise of ensuring the degree of orientation. The rubber-based binder used in the present invention is selected from the group consisting of: chlorinated polyethylene, nitrile rubber, ethylene rubber, neoprene butadiene rubber, polyester rubber, styrene butadiene rubber, butyl rubber, polyisobutylene rubber, polysulfide A combination of oak, silicone rubber, hydrogenated nitrile rubber, polyisoprene rubber, thermoplastic polymer and its niobium. In a preferred embodiment, one or more of nitrile rubber, polyisobutylene rubber, and thermoplastic polymer are used.

In order to make the rubber and the magnetic powder have a good affinity to increase the filling ratio of the magnetic powder in the magnet, the rubber needs to be modified. The rubber modification method includes one or more of the following: processing co-kneading method, thermoplastic refining method, several rubber blending methods, solution dissolving method, functional group grafting method, and the like. The processing aid mixing method means that the rubber is easily mixed to obtain better plasticity and filling characteristics under the condition of processing aid, and the hot plasticating method means that the rubber obtains plasticity under the condition of heating, and the rubber blending is utilized more. The characteristics of the oak are functional and reinforcing in the case of uniform mixing. The solvent dissolution method is to melt the rubber by using a solvent. The functional group grafting method is to make the rubber have a certain function and will have work. The ability of the molecule molecules to be grafted onto the rubber molecular backbone to achieve the desired performance is a relatively common method.

The processing aids used in the present invention include one or more of an anti-oxygen hydrazine, a crosslinking agent, a coupling cross-section, a plasticizer, a lubricant, a solvent, and an antioxidant.

The manufacturing method of the high performance anisotropic flexible bonded NdFeB magnet provided by the invention is as follows: the rubber-based adhesive which has been modified and the surface treated anisotropy

HDDR NdFeB magnetic powder and auxiliaries are mixed evenly according to the ratio. The mixing method adopts the mixing method, the opening method, the stirring method or the screw mixing method, and then the mixed mixture is pressed, injected or extruded. Forming a flexible magnet of a certain thickness; applying a magnetic field orientation when the magnet is formed, and the circumferentially oriented magnetic field includes one or more of a static magnetic field, an alternating magnetic field, or a pulsed magnetic field.

Under normal circumstances, the strength of rubber products is low, which cannot be satisfied under many conditions of use. For this reason, the flexible NdFeB magnets must be cross-linked to make the rubbers in the case of strength requirements. A network crosslinked structure is formed to obtain higher strength. The cross-linking mode may be one of the following: electron beam radiation, infrared radiation, hot air heating, bubbling bed, microwave irradiation, radiation, flat plate heating, etc. In a more preferred embodiment, a flat plate or hot air heating method is used.

The method for manufacturing the high-performance anisotropic flexible bonded NdFeB magnet of the present invention further comprises the surface protection treatment of the obtained magnet, which is one or more of spraying, gas phase, and protective paint.

Compared with the existing flexible bonded NdFeB magnets, the anisotropic HDDR NdFeB magnetic powder is made into a flexible magnet of a certain thickness by pressing or extrusion or rubber injection molding, and has high magnetic properties and good flexibility. Good reliability, high production efficiency, low cost, etc., and at the same time it has good flexibility and magnetic properties; the magnet can be wound around its thickness Ten times on the shaft, no cracking, the highest magnetic performance of the magnet can reach i30kJ/ni ³ , and the maximum operating temperature is up to 120Ό. The invention uses anisotropic titanium-iron-boron magnetic powder with higher magnetic properties for flexible bonded magnets. In the preparation, the magnetic properties are further improved to exceed the level of the isotropically bonded NdFeB magnets. The application range of the flexible magnets is further expanded from 3⁄4, to meet the global market demand, fill in the gaps at home and abroad, and change the rare earths in China. Current status of the magnetic industry.

Implementation I

A commercially available HDDR anisotropic NdFeB magnetic powder having a particle size of less than 250 μm (nominal maximum magnetic energy product 320 kJ./m ³ :) was selected. The ratio of the magnet formulation (weight ratio) is H.DDR anisotropic NdFeB magnetic powder 100g, nitrile rubber 3,5g, ethylene-vinyl acetate copolymer 0,5g, silane couple 0.3g, organic gas 0.9g, hard 0.3 g of strontium citrate, OJg of antioxidant, 0.3 g of tackifier, and 0.3 g of flowing exhaust gas. Manufacturing process: Mix the magnetic powder and the silane coupling agent uniformly. Mix the magnetic powder and other raw materials into a sheet on the open mill (repeated 20 times)...-■> Break the material into 3~6mm pellets > Preheating on the flat vulcanizing machine (100 °C * 20min) → Orienting in a static magnetic field of 2T, pressing into a magnetic sheet with a thickness of 2.0 hidden → thermal cross-linking for 20 min under i50C condition, the magnetic sheet is wound around Φ20 No cracks appear on the round bar, and the performance of the test magnet is as follows:

Example 2 Screening commercially available HDDR anisotropic NdFeB magnetic powder with a particle size of 60-180 μm (nominal maximum energy product 320kJZm ³ ) „ Magnet formulation ratio (weight ratio) is HDDR anisotropic NdFeB magnetic powder 100g, chlorination Polyethylene 3, 5g, ethylene-vinyl acetate copolymer 0,5g, silane coupling 0. 3g, organic peroxide 0,9g, bismuth stearate 0.3g, antioxidant C g, tackifier 0,3g , Flow venting agent 0.3g, Manufacturing process: Mix the magnetic powder and the silane coupling agent uniformly - Mix the magnetic powder and other raw materials into a sheet on the open mill (repeated 20 times)

Set 70Ό) → Orientation under the action of 3T static magnetic field and 60Hz, 0.5T alternating magnetic field, extrusion width of 25mm, thickness of 2,0mm magnetic sheet. → Thermal cross-linking 15niin under 140 conditions, magnetic sheet No crack occurred on the round bar around Φ20, and the performance of the test magnet was as follows;

Implementation down 3

Screening. A commercially available HDDR anisotropic NdFeB magnetic powder having a particle size of 60 150 μm (nominal maximum energy product 320 kJ/m ³ ). The proportion of the magnet formulation (weight ratio) is 100 g of HDDR anisotropic NdFeB magnetic powder, 3 g of polyisobutylene rubber, 0.4 g of butyl rubber, 0.3 g of silane coupling agent, and there are: 0.8 g of machine vaporization, stearic acid 0 , 3g, anti-aging agent O.lg, tackifier 0.3g, flow exhaust agent 0. 3g, manufacturing process: mixing magnetic powder and silicon germanium series agent hooks → mixing magnetic powder and other raw materials on the coke machine Sheet (repeated 20 times) .. > Heat the sheet 3⁄4 material into the drum to 140€→Inject the material into the cavity and keep the pressure 111】1→ at 2T The magnetic field and the pulsed magnetic field with a peak value of 2 共同 are oriented together, and pressed into a magnetic sheet having a thickness of 2.0 mm _→ thermally crosslinked at 140 C for 15 min, and the magnetic sheet is wound around a round rod of Φ 20 without cracks. The performance is as follows:

Screening. A commercially available HDDR anisotropic ferro-iron-boron magnetic powder having a particle size of 75 150 μm (nominal maximum energy product 320 kJ/m ³ ). The proportion of the magnet formulation (weight ratio) is 100 g of HDDR anisotropic NdFeB magnetic powder, 3 g of polyisobutylene rubber, 0.5 g of butyl rubber, 0.3 g of silane coupling agent, 0.8 g of organic pervaporation, 0,5 g of stearic acid. , Antioxidant O.lg, Flow Exhaust ^ 0.3g, Manufacturing Process: Use solvent to make bonding ^, auxiliary into colloid → add magnetic powder into the gel and stir evenly -. > Bake 5h to remove all solvent to form 3⁄4 material - > Breaking the billet into pellets of 1 to 3 mm → preheating on the flat vulcanizer (140C*10min) → Orienting the magnetism with a thickness of LOmoi under the action of a static magnetic field of 3T and a pulsed magnetic field with a peak of 2T Slice → at 140. Thermal crosslinking under C conditions

A vapor phase is deposited on the isomer coating of the dimethyl styrene resin (paryiene treatment). The magnet was subjected to a neutral salt spray test (5% NaCI solution / 35 C*72 h) and observed with a 5x magnifying glass without rust. The magnetic sheet is wound around a round rod of Φ]0, and the performance of the test magnet is as follows:

Implementation 5

Commercially available anisotropic neodymium iron magnetic powder (nominally Nie magnetic energy product 320kJ/m ³ ) and particle size of 80 μ m or less isotropic fast quenching NdFeB magnetic powder (grade XQP16 10) ). The proportion of the magnet formulation (weight ratio) is HDDR. Anisotropic NdFeB magnetic powder 80g, isotropic quenching NdFeB magnetic powder 20g, polyisobutylene rubber 3,0g butyl rubber 0.5g, silane coupling agent 0.3g, organic Peroxide 0.8g, stearic acid 0.5g, anti-aging agent 0, lg, flow venting agent 0,3g, manufacturing process: using solvent to make binder and auxiliary agent into colloid - adding magnetic powder to the gel body and stirring →Bake at 80 °C for 5 h to remove all solvents to form 3⁄4 material.. *Break the billet into pellets of 1 ~ 3 mm → preheat the pellet on the flat vulcanizer (140 °C * 10 min) → static magnetic field at 3T and The pulsed magnetic field having a 峄 value of 2T was combined and oriented to be pressed into a magnetic sheet having a thickness of 0.5 mm. The magnetic sheet is wound around the round bar of Φ5 without cracks. The performance of the test magnet is as follows:

Claims

^'j "?

ί, an anisotropic flexible bonded NdFeB magnet, whose composition and weight are:

HDDR anisotropic NdFeB magnetic powder 87-97%:

Modified rubber adhesive 1 -8%;

Processing tincture 0 5%.

2. The anisotropic flexible bonded neodymium iron neodymium magnet according to claim 1, wherein the rubber-based adhesive is selected from the group consisting of chlorinated polyethylene, nitrile rubber, ethylene rubber, neoprene, and cisplatin. One or more of rubber, urethane rubber, butyl rubber, butyl rubber, polyisobutylene rubber, polysulfide rubber, silicone rubber, hydrogenated nitrile rubber, polyisoprene rubber and thermoplastic polymer

3. The anisotropic flexible bonded NdFeB magnet according to claim 2, wherein the rubber modification method comprises a thermoplastic refining method, a processing aid mixing method, a rubber blending method, and a solvent dissolution method. And one or more of the functional group grafting methods.

The anisotropic flexible bonded neodymium iron neodymium magnet according to claim 1, characterized in that the HDDR anisotropic NdFeB magnetic powder is a magnetic material or a permanent magnet 'iron gas magnetic powder Or wherever.

The anisotropically flexible bonded NdFeB magnet according to claim 1, wherein the HDDR anisotropic NdFeB magnetic powder has a particle diameter of 250 μηη or less.

6. The anisotropic flexible bonded neodymium iron boron magnet according to claim 1, wherein the HDDR anisotropic ferroniobium. boron magnetic powder has a weight content of 90-95%. The HDDR anisotropic neodymium iron boron magnetic powder is surface-treated, and the surface treatment method is selected from the group consisting of organic or inorganic rubber coating, chemical or physical deposition, reactive passivation, and combinations thereof. 8. The anisotropic flexible bonded neodymium iron neodymium magnet according to claim 1, wherein the processing aid comprises an antioxidant, a crosslinking agent, a coupling agent, a plasticizer, a lubricant, and a dissolution agent. One or more of a dose and an antioxidant.

A method of manufacturing an anisotropic flexible bonded NdFeB magnet according to claim 1, comprising the steps of:

(1) The rubber-bonded and HDDR anisotropic NdFeB magnetic powder and the processing aid which have been modified and treated are uniformly mixed to obtain a dip material, and the mixing method adopts a mixing method, an opening method, Stirring method or screw mixing method;

(2) using a pressing, extrusion or rubber injection molding method, the rubber compound is made into a flexible magnet of a constant thickness, and an orientation magnetic field is applied during molding of the flexible magnet, and the radial magnetic field used includes a static magnetic field and One or more of a variable magnetic field or a pulsed magnetic field.

10. The method of manufacturing an anisotropic flexible bonded neodymium iron boron magnet according to claim 9, wherein the method further comprises the step of crosslinking the obtained magnet, wherein the crosslinking is performed by using electrons. Beam radiation, infrared radiation, hot air heating, ebullating bed, oscillating radiation, radiation radiation or flat heating.

1 L The method for manufacturing an anisotropic flexible bonded NdFeB magnet according to claim 9, wherein the method further comprises the step of performing a surface protection treatment on the flexible magnet, the processing method being selected from One or /L of spray coating, vapor deposition, and protective paint.