Flexible bonded magnet and preparation method thereof

A bonded magnet and flexible technology, applied in the direction of magnetic objects, inductor/transformer/magnet manufacturing, adhesives, etc., can solve the problems of low production efficiency, large line deformation rate, and not too high operating temperature, so as to improve production efficiency and high Effects of mechanical properties and excellent flexibility

Inactive Publication Date: 2014-06-11
BEIJING ZHONG KE SAN HUAN HI TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, flexible bonded magnets also have their own shortcomings. The biggest problem is that the operating temperature should not be too high
This is mainly due to the limitation of the binder used in the flexible magnet. In a high temperature environment, the binder itself may decompose, destroy and lose flexibility; in addition, the general processing technology of flexible magnets is calendering or extrusion manufacturing process. Due to the influence of internal stress, the magnetic sheet will increase in thickness direction and shrink in length direction at high temperature, which makes the air gap between the stator and rotor larger than the design value when fan motor products work at high temperature, resulting in these The messy noise produced by motor products may even cause the rotor of the motor to be stuck, and the motor will be scrapped. In severe cases, it may pose a threat to human safety
At present, the most widely used chlorinated polyethylene as a flexible magnet on the market has a relatively simple manufacturing process, which can generally be divided into three processes: mixing, kneading, and calendering. In the low-end field, there are no special requirements for dimensional accuracy and deformation rate
Usually, flexible magnets with nitrile rubber or silicone rubber as the main binder can be used in some industries that require high temperature environments. However, these flexible magnets have a small volume expansion rate when the ambient temperature is above 100°C The linear deformation rate is relatively large (the thickening rate in the thickness direction and the shrinkage rate in the length direction are greater than 5%, while the difference in volume expansion rate is very small), and its processing technology is relatively complicated, requiring secondary vulcanization after rolling. low production efficiency
This limits the development of rubber-like flexible magnets

Method used

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  • Flexible bonded magnet and preparation method thereof

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preparation example Construction

[0016] The invention provides a high-temperature-resistant flexible bonded magnet and its preparation method, which is similar to the general flexible magnet processing method. Firstly, various raw materials are proportioned according to the formula requirements, and they are fully mixed, and then mixed in an open mill or The kneading is uniform in a belt-press kneader, and the obtained kneaded product is rolled into a predetermined thickness in a calender to obtain a single-layer thin magnetic sheet. Then put 2-5 sheets of the thin magnetic sheets into a mold, heat and hold pressure for 10-30 minutes to obtain a composite magnetic sheet, the holding temperature is 150-170° C., and the holding pressure is 5-20 MPa. This heat preservation and pressure holding process is the process of eliminating magnet strain and internal stress added in the preparation method of the present invention. This process is actually compressing the magnetic sheet, which helps to eliminate the strain ...

Embodiment 1

[0028] Bonded NdFeB magnetic powder (particle size 60μm, coupled with 0.1wt% surfactant vinyltriethoxysilane) 92wt%, polyurethane 5.0wt%, zinc stearate 0.8wt%, phthalate Dioctyl ester 1.0wt%, epoxidized soybean oil 1.0wt%, antioxidant triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate] 0.2wt%. First put the above components and magnetic powder into a high-speed mixer and mix them evenly, then knead the resulting mixture fully with an open mill, then put the resulting mixture on a calender to obtain a thin magnetic sheet with a thickness of 0.6mm, and finally put the 2-layer The thin magnetic sheets are laminated, compressed and maintained at 150° C. under a pressure of 5 MPa for 10 minutes, and finally a magnetic sheet with a thickness of 1.0 mm is obtained. The specific parameters are shown in Table 1 below.

Embodiment 2

[0030]Bonded NdFeN magnetic powder (particle size 40μm, coupled with 3wt% surfactant γ-aminopropyltriethoxysilane) 97wt%, polyethylene 2.5wt%, silicone oil 0.1wt%, dioctyl phthalate 0.1wt% ester, 0.1wt% epoxidized soybean oil, 0.2wt% antioxidant thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]. First put the above components and magnetic powder into a high-speed mixer and mix evenly, then fully knead the resulting mixture with a belt-pressure kneader, then put the resulting mixture on a calender to obtain a thin magnetic sheet with a thickness of 0.6 mm, and finally Laminate three layers of thin magnetic sheets, compress and maintain the shape at 160°C under a pressure of 8 MPa for 15 minutes, and finally obtain a magnetic sheet with a thickness of 1.0 mm. The specific parameters are shown in Table 1 below.

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Abstract

The invention discloses a flexible bonded magnet which comprises the following components in percentage by weight: 85-97 percent of magnetic powder, 0.1-3 percent accounting for the content of the magnetic powder of coupling agent, 2.5-12 percent of bonding agent and 0.3-3 percent of processing aid, wherein the bonding agent is a thermoplastic elastomer; meanwhile, the flexible bonded magnet also comprises 0.05-0.2 percent by weight of antioxidant. A preparation method is realized by laminating monolayer magnetic sheets formed by a calender into a die for heat and pressure preserving treatment. The bonded magnet produced by adopting a process and a formula disclosed by the invention has the advantages of high magnetic performance, high mechanical performance and excellent flexibility. The linear deformation rate of the bonded magnet at the working temperature of 40DEG below zero and 150DEG C is lower than 1 percent; meanwhile, secondary vulcanization after calendering is avoided, and thus the production efficiency is increased.

Description

technical field [0001] The invention relates to a flexible bonded magnet and a preparation method thereof, in particular to a high temperature resistant flexible bonded magnet and a preparation method thereof. Background technique [0002] In recent years, with the continuous development of social information technology, people have an urgent demand for further thinning and high efficiency of information products, which puts forward higher requirements for the performance of magnetic materials. For example, high-fidelity planar speakers need high-performance bonded magnets with large area and thin thickness; notebook computers need thinner and higher-power fan motors to meet heat dissipation requirements; household appliances such as washing machines and fans also need more stable direct-drive motors ; Ultra-thin flexible sensors are required in multimedia devices such as mobile phones and mp4, and high-performance flexible bonded magnets can meet these requirements. Flexib...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/117H01F41/02C09J175/04C09J123/06C09J177/00C09J167/02C09J133/00B22F3/16
Inventor 蔡道炎敖学如饶晓雷胡伯平
Owner BEIJING ZHONG KE SAN HUAN HI TECH
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