Injection molding magnet material, preparation method and injection molding magnet

Abstract

The invention relates to the technical field of injection molding magnetic powder materials, and discloses an injection molding magnet material, a preparation method and an injection molding magnet, and the injection molding magnet material is prepared from the following raw materials in parts by weight: 80-92 wt.% of magnetic powder; 3-9 wt.% of a binder A; 3-9 wt.% of a binder B; 0.3 to 2 wt.% of a coupling agent; 0.2 to 1.5 wt.% of an auxiliary agent; the binder A and the binder B are PA10T / X, the relative viscosity of the binder A and the relative viscosity of the binder B range from 1 to 2, and the difference value between the relative viscosity of the binder A and the relative viscosity of the binder B is not less than 0.3. The binding agent A and the binding agent B with different relative viscosities are adopted for improving the mechanical property and the fluidity of the magnetic material correspondingly, it can be guaranteed that the magnetic material has good size stability in a high-humidity environment and has high strength in a low-temperature environment, the fluidity of the magnetic material is greatly improved, and the magnetic material has the good mechanical property. Meanwhile, the material cost of the injection molding magnet material is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of injection molding magnetic powder materials, and in particular to an injection molding magnet material and a preparation method, and an injection molding magnet. Background Art

[0002] Injection molded magnets are widely used in various motors and electronic products. In high humidity environments, magnets are required to have good dimensional stability and high strength; in low temperature (-40°C) environments, magnets are required to have good strength (such as no cracking). Under this requirement, the plastic substrate of the injection molded magnet is required to have low water absorption and good low temperature strength. At the same time, the injection molding method requires the injection molded magnet material to have good fluidity to facilitate injection molding, which requires the binder to have high fluidity. Injection molded magnets are prepared by injection molding magnetic powder materials through an injection molding machine. The injection molded magnetic powder materials are compounded by permanent magnetic powder (permanent magnetic ferrite powder, rare earth neodymium iron boron magnetic powder, etc.) and polymer resins (nylon series resins, thermoplastic polyester elastomers TPEE, etc.) that act as binders.

[0003] In the process of preparing injection molding magnetic powder materials, nylon series resins such as PA6, PA66, PA12, PA11 or PA612 are commonly used. Among them, PA12 has less low-temperature strength decay and better low-temperature strength, so PA12-based injection molding magnet materials are used for injection molding to obtain PA12-based injection molding magnets. However, the current technical barriers to synthesizing PA12 plastics are high, the synthesis methods are complex, and the number of suppliers is small, resulting in high prices for PA12 plastics, which in turn leads to high costs for preparing PA12-based injection molding magnets, seriously affecting the promotion and use of PA12-based injection molding magnet materials. In addition, the fluidity of existing PA12-based injection molding magnet materials is poor. Even for low-grade injection molding magnet materials with a relatively high proportion of PA12, the melt index is less than 100g / 10min, resulting in extreme molding process conditions and a narrow control range. This seriously affects the service life of injection molding machines and injection molds, and increases equipment costs and management costs. Summary of the invention

[0004] The purpose of the present invention is to overcome the problems of low fluidity and high cost of existing PA12-based injection molding magnet materials, and to provide an injection molding magnet material and a preparation method, and an injection molding magnet.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] An injection molding magnet material, wherein the raw materials for preparing the injection molding magnet material include, by weight:

[0007] Magnetic powder 80~92wt.%;

[0008] Binder A3~9wt.%;

[0009] Binder B 3-9wt.%;

[0010] Coupling agent 0.3-2wt.%;

[0011] Additives 0.2~1.5wt.%;

[0012] The binder A and the binder B are long carbon chain nylon PA10T / X, the relative viscosity of the binder A and the relative viscosity of the binder B are in the range of 1 to 2, and the difference between the relative viscosity of the binder A and the relative viscosity of the binder B is not less than 0.3.

[0013] In the technical solution of the present invention, the raw materials of the injection molding magnet material include magnetic powder, binder A, binder B, coupling agent and auxiliary agent, wherein both binder A and binder B use long carbon chain nylon PA10T / X, and the relative viscosity of binder A and binder B are limited to 1-2, and the difference between the relative viscosity of binder A and the relative viscosity of binder B is not less than 0.3. Through a large number of experimental explorations by the inventor, it is found that there are existing composite materials such as PA4T / X, PA5T / X, and PA6T / X, but due to the short carbon chain, their low temperature strength is not good, and they cannot meet the fluidity requirements of the injection molding magnet material. Therefore, the binders A and B in the injection molding magnet material of the present invention use long carbon chain nylon PA10T / X with different relative viscosities. PA10T / X is a new long-chain nylon with lower price, wider raw material source and simpler synthesis process. It is formed by polymerization of "PA10T" + long carbon chain "X". The variability of "X" branch chain makes the relative viscosity of PA10T / X adjustable between 1 and 2, and has density, melting point, water absorption, mechanical properties, etc. basically equivalent to PA12. In the magnetic material, two long-chain nylon materials with different viscosities, binder A and B, are used, and the relative viscosity range is 1 to 2. The higher viscosity binder A provides mechanical properties, and the lower viscosity binder B provides a high melt index. Different viscosities are used to improve the mechanical properties and high melt index of the magnetic material respectively. Using PA10T / X instead of the existing PA12 plastic for the preparation of injection molded magnet materials can ensure that the magnetic material has good dimensional stability in a high humidity environment and high strength in a low temperature environment.

[0014] As a preferred embodiment of the present invention, the magnetic powder is any one of ferrite, neodymium iron boron, and samarium iron nitrogen, or a combination of at least two thereof, and the ferrite includes at least one of strontium ferrite magnetic powder and barium ferrite magnetic powder.

[0015] As a more preferred embodiment of the present invention, the average particle size of the magnetic powder is 0.5-100 μm.

[0016] As a preferred embodiment of the present invention, PA10T / X is obtained by modifying polydecane terephthalamide (PA10T) with X, and based on the molar percentage of PA10T / X, the 10T unit content is 70-95 mol.%, and the X unit content is 5-30 mol.%; wherein the X unit is a fatty chain, which is a straight chain or branched chain of 4 to 16 carbon atoms.

[0017] As a more preferred embodiment of the present invention, the X unit is a saturated fatty chain having 4 to 16 carbon atoms, and the PA10T / X is selected from at least one of PA10T / 4, PA10T / 5, PA10T / 6, PA10T / 7, PA10T / 8, PA10T / 9, PA10T / 10, PA10T / 11, PA10T / 12, PA10T / 13, PA10T / 14, PA10T / 15, and PA10T / 16.

[0018] As a more preferred embodiment of the present invention, the X unit is a saturated fatty chain having 8 to 14 carbon atoms.

[0019] As a preferred embodiment of the present invention, the ratio of the added weight of the binder A to the added weight of the binder B is 1:0.8-2, and more preferably, the ratio of the added weight of the binder A to the added weight of the binder B is 1:1-1.5.

[0020] As a preferred embodiment of the present invention, the coupling agent is at least one of a titanate coupling agent, an aluminate coupling agent, a silane coupling agent, a phosphate coupling agent, and a zirconate coupling agent. The silane coupling agent used is one or more of silane coupling agent KH550, silane coupling agent KH560, silane coupling agent KH570, etc. The titanate coupling agent used is for example isopropyl tri (dioctyl) pyrophosphate titanate; the aluminozirconate coupling agent is for example, and the titanate coupling agent is for example a monoalkoxy pyrophosphate type.

[0021] As a preferred embodiment of the present invention, the auxiliary agent is a heat stabilizer and a lubricant, the content of the heat stabilizer is 0.05-0.5wt.%, and the content of the lubricant is 0.15-1wt.%. The heat stabilizer is at least one of basic lead salts, polyesters, metal soaps, organic tin, etc., and the lubricant is at least one of stearic acid, amides, esters, alcohols, waxes, etc.

[0022] As a preferred embodiment of the present invention, the auxiliary agent also includes at least one of a dispersant, a plasticizer, and an antioxidant. The dispersant is, for example, sodium hexametaphosphate, sodium polyacrylate, etc.; the plasticizer is, for example, modified citrate, epoxy soybean oil, phthalates, etc.; the antioxidant includes a hindered phenol antioxidant.

[0023] As a more preferred embodiment of the present invention, the raw materials for preparing the injection molding magnet material include, by weight:

[0024] Magnetic powder 86.5-90.5wt.%; binder A 3.2-6.1wt.%; binder B 4.1-7.3wt.%; coupling agent 0.3-2wt.%; heat stabilizer 0.05-0.5wt.%; the lubricant content is 0.15-1wt.%;

[0025] The binder A and the binder B are PA10T / X, the relative viscosity of the binder A and the relative viscosity of the binder B are in the range of 1 to 2, the difference between the relative viscosity of the binder A and the relative viscosity of the binder B is not less than 0.3, and the ratio of the added weight of the binder A to the added weight of the binder B is 1:0.8 to 2.

[0026] Another aspect of the present invention provides a method for preparing an injection molded magnet material, comprising the following steps:

[0027] S1, spraying the coupling agent onto the magnetic powder under stirring at 80-120° C., stirring, then adding the binder A, the binder B, and the auxiliary agent, and continuing to stir evenly at 80-120° C. to obtain a mixed material;

[0028] S2. Add the obtained mixture into a twin-screw extruder, melt extrude into wire at 220° C. to 280° C., cool, and pelletize to obtain an injection-molded magnet material.

[0029] In the above technical scheme, the magnetic powder is first modified with a coupling agent, and then the modified magnetic powder is stirred and mixed with binder A, binder B, and an auxiliary agent, and then extruded and granulated at 220°C to 280°C by a twin-screw extruder to obtain an injection molding magnet material containing long carbon chain nylon. The preparation method of the present invention adopts a one-time extrusion process, which is simple and easy to operate. After one-time injection molding, the injection molding magnet material can be given a good appearance, dimensional stability in a high humidity environment, and high strength in a low temperature environment, which is convenient for industrial promotion. In addition, during the twin-screw extrusion process, the odor of PA10T / X is much lower than that of PA12, which is more friendly to operators.

[0030] As a preferred embodiment of the present invention, in step S1, the coupling agent is dissolved in a diluent, dissolved evenly, and then sprayed on the NdFeB magnetic powder under stirring, the diluent includes ethanol and / or isopropanol, and the ratio of the diluent to the coupling agent is 1 to 2:1.

[0031] As a preferred embodiment of the present invention, in step S2, the temperature in the twin-screw extruder is controlled to be 230°C to 250°C, and the granulation is performed by melt extrusion at 230°C to 250°C. In the mixing process of the magnet material, the temperature has a direct relationship with the final performance of the product. If the temperature is too low, the uniformity of the material is poor; if the temperature is too high, the strength and magnetic properties of the material will be affected. Therefore, the present invention adopts melt extrusion granulation at 230°C to 250°C.

[0032] The present invention also provides an injection-molded magnet, which is obtained by injection molding the above-mentioned injection-molded magnet material through an injection molding machine. The injection-molded magnet prepared by the injection-molded magnet material of the present invention not only has high magnetic properties and strength, but also has good corrosion resistance, low manufacturing cost, and is easy to promote and apply.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The raw materials of the injection molding magnet material of the present invention include magnetic powder, binder A, binder B, coupling agent and additives. Binders A and B are two long carbon chain nylon materials with different viscosities, and their relative viscosity range is 1 to 2. Different viscosities are used to improve the mechanical properties and melt index of the magnetic material, respectively, which can ensure that the magnetic material has good dimensional stability in a high humidity environment and high strength in a low temperature environment, greatly improve the fluidity of the magnetic material, and reduce the material cost of the injection molding magnet material.

[0035] 2. After testing, the injection-molded magnet material prepared by the present invention has good tensile strength, impact strength, and material fluidity, and the MFR is between 105 and 360 g / 10 min, and has good processability; after the high temperature and high humidity environment test, the sample has a good appearance and stable size, and can meet the use requirements of the high humidity environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The MFR test results of PA10T / X for various brands of injection molding magnet materials;

[0037] Figure 2 The prices of various grades of PA10T / X injection molding magnet materials are shown below. DETAILED DESCRIPTION

[0038] In order to more clearly describe the invention purpose, technical scheme and technical effect advantages in the specific implementation case of the present invention, the scheme in the specific embodiment will be described in detail in combination with the drawings of the specification of the present invention. The specific technical scheme involved in the following specific embodiments is only for a clear and complete description of the innovative technical scheme of the present invention. It is only a part of the specific implementation scheme that can be adopted by the present invention, not all embodiments, and should not be understood as a limitation on the innovative scheme of the present invention. Any scheme adopting the same inventive concept of the present invention should be included in the protection scope of the present invention.

[0039] Secondly, the description of the drawings in the specific embodiments of the present invention is only for the convenience of technical personnel to understand the solution of the present invention. The partial details in the drawings are for the convenience of clearly presenting the technical solution. It should not be considered that all technical features in the drawings must be included in the specific implementation cases, and the detailed features in the drawings should not be identified as additional limitations on the innovative technical solution of the present invention. The components in the various embodiments described and shown in the drawings can be combined and arranged according to different configurations, and these changes in combination and arrangement should be identified as part of the entire embodiment of the innovative solution of the present invention and included in the scope of protection of the present invention.

[0040] The binder A and the binder B used in the following specific embodiments are both long carbon chain nylon PA10T / X. PA10T / X is obtained by using polydecane terephthalamide (PA10T) after X modification. The X unit is a saturated fatty chain with 8 to 14 carbon atoms. It is the M series of Company A and has different relative viscosities. The relative viscosities of binder A and binder B are measured by a capillary viscometer. The price cost of PA10T / X is about 70% of that of PA12. After testing, the melting point of PA10T / X is about 172°C, which is basically equivalent to PA12 (the melting point range of PA12 is 172-178°C), ensuring the processability of PA10T / X for magnet material preparation.

[0041] Example 1

[0042] The present embodiment provides an injection molding magnet material, wherein the raw materials include, by weight: 86.5wt.%, ferrite powder, 6.10wt.%, binder A, 6.10wt.%, binder B, 0.75wt.%, coupling agent, 0.05wt.%, heat stabilizer, and 0.5wt.% lubricant, wherein the relative viscosity of binder A is 2.0, and the relative viscosity of binder B is 1.0, and the relative viscosity here refers to the ratio of the absolute viscosity of a liquid to the absolute viscosity of water at the same temperature.

[0043] The preparation method of injection molding magnet material is as follows:

[0044] S1. Dissolve the coupling agent in ethanol and dissolve it evenly. Then spray it on the magnetic powder under stirring at 80-120°C and mix for 30-60 minutes. Then add binder A, binder B, heat stabilizer and lubricant. Continue stirring at 80-120°C for 30-60 minutes until the mixture is uniform to obtain a mixed material.

[0045] S2. The obtained mixed material is put into a twin-screw extruder, melt-extruded into a wire at 240±5° C., cooled, and pelletized to obtain the injection-molded magnet material of this embodiment.

[0046] Example 2

[0047] The present embodiment provides an injection molding magnet material, wherein the raw materials include, by weight: 86.5wt.%, ferrite powder, 4.78wt.%, binder A, 7.17wt.%, binder B, 1.00wt.%, coupling agent, 0.05wt.%, heat stabilizer, and 0.5wt.% lubricant, wherein the relative viscosity of binder A is 2.0, and the relative viscosity of binder B is 1.0.

[0048] The preparation method of injection molding magnet material is as follows:

[0049] S1. Dissolve the coupling agent in ethanol and dissolve it evenly. Then spray it on the magnetic powder under stirring at 80-120°C and mix for 30-60 minutes. Then add binder A, binder B, heat stabilizer and lubricant. Continue stirring at 80-120°C for 30-60 minutes until the mixture is uniform to obtain a mixed material.

[0050] S2. The obtained mixed material is put into a twin-screw extruder, melt-extruded into a wire at 250±5° C., cooled, and pelletized to obtain the injection-molded magnet material of this embodiment.

[0051] Example 3

[0052] The present embodiment provides an injection molding magnet material, wherein the raw materials include, by weight: 87.6 wt.%, ferrite powder, 5.52 wt.%, binder A, 5.52 wt.%, binder B, 0.76 wt.%, coupling agent, 0.10 wt.%, heat stabilizer, and 0.5 wt.% lubricant, wherein the relative viscosity of binder A is 1.8, and the relative viscosity of binder B is 1.1.

[0053] The preparation method of injection molding magnet material is as follows:

[0054] S1. Dissolve the coupling agent in ethanol and dissolve it evenly. Then spray it on the magnetic powder under stirring at 80-120°C and mix for 30-60 minutes. Then add binder A, binder B, heat stabilizer and lubricant. Continue stirring at 80-120°C for 30-60 minutes until the mixture is uniform to obtain a mixed material.

[0055] S2. The obtained mixed material is put into a twin-screw extruder, melt-extruded into a wire at 230±5° C., cooled, and pelletized to obtain the injection-molded magnet material of this embodiment.

[0056] Example 4

[0057] The present embodiment provides an injection molding magnet material, wherein the raw materials include, by weight: 87.6wt.%, ferrite powder, 4.34wt.%, binder A, 6.51wt.%, binder B, 0.75wt.%, coupling agent, 0.30wt.%, heat stabilizer, and 0.5wt.% lubricant, wherein the relative viscosity of binder A is 1.8, and the relative viscosity of binder B is 1.1.

[0058] The preparation method of the injection molded magnet material is the same as that in Example 1.

[0059] Example 5

[0060] The present embodiment provides an injection molding magnet material, wherein the raw materials include, by weight: 89.4wt.%, ferrite powder, 4.75wt.%, binder A, 4.75wt.%, binder B, 0.75wt.%, coupling agent, 0.05wt.%, heat stabilizer, and 0.3wt.% lubricant, wherein the relative viscosity of binder A is 1.7, and the relative viscosity of binder B is 1.2.

[0061] The preparation method of the injection molded magnet material is the same as that in Example 1.

[0062] Example 6

[0063] The present embodiment provides an injection molding magnet material, wherein the raw materials include, by weight: 89.4wt.%, ferrite powder, 3.52wt.%, binder A, 5.28wt.%, binder B, 0.75wt.%, coupling agent, 0.05wt.%, heat stabilizer, and 1.0wt.% lubricant, wherein the relative viscosity of binder A is 1.7, and the relative viscosity of binder B is 1.2.

[0064] The preparation method of the injection molded magnet material is the same as that in Example 1.

[0065] Example 7

[0066] The present embodiment provides an injection molding magnet material, wherein the raw materials include, by weight: 90.5wt.%, ferrite powder, 4.10wt.%, binder A, 4.10wt.%, binder B, 0.75wt.%, coupling agent, 0.05wt.%, heat stabilizer, and 0.5wt.% lubricant, wherein the relative viscosity of binder A is 1.6, and the relative viscosity of binder B is 1.3.

[0067] The preparation method of the injection molded magnet material is the same as that in Example 1.

[0068] Example 8

[0069] The present embodiment provides an injection molding magnet material, wherein the raw materials include, by weight: 90.5wt.%, ferrite powder, 3.28wt.%, binder A, 4.92wt.%, binder B, 0.75wt.%, coupling agent, 0.05wt.%, heat stabilizer, and 0.5wt.% lubricant, wherein the relative viscosity of binder A is 1.6, and the relative viscosity of binder B is 1.3.

[0070] The preparation method of the injection molded magnet material is the same as that in Example 1.

[0071] Example 9

[0072] The present embodiment provides an injection molding magnet material, and the raw materials include, by weight: 90.5wt.%, NdFeB magnetic powder, 4.10wt.%, binder A, 4.10wt.%, binder B, 0.75wt.%, coupling agent, 0.05wt.%, heat stabilizer, and 0.5wt.% lubricant. The relative viscosity of binder A is 1.6, and the relative viscosity of binder B is 1.3. The magnetic energy product of NdFeB magnetic powder used in this embodiment is 8MGOe, and the intrinsic coercive force is 7kOe.

[0073] The preparation method of the injection molded magnet material is the same as that in Example 1.

[0074] Example 10

[0075] The present embodiment provides an injection molding magnet material, wherein the raw materials include, by weight: 87.6wt.%, ferrite powder, 6.02wt.%, binder A, 4.82wt.%, binder B, 0.76wt.%, coupling agent, 0.30wt.%, heat stabilizer, and 0.5wt.% lubricant, wherein the relative viscosity of binder A is 1.8, and the relative viscosity of binder B is 1.1.

[0076] The preparation method of the injection molded magnet material is the same as that in Example 1.

[0077] Embodiment 11

[0078] The present embodiment provides an injection molding magnet material, wherein the raw materials include, by weight: 87.6wt.%, ferrite powder, 3.61wt.%, binder A, 7.23wt.%, binder B, 0.76wt.%, coupling agent, 0.30wt.%, heat stabilizer, and 0.5wt.% lubricant, wherein the relative viscosity of binder A is 1.8, and the relative viscosity of binder B is 1.1.

[0079] The preparation method of the injection molded magnet material is the same as that in Example 1.

[0080] Comparative Example 1

[0081] The injection molding magnet material of this comparative example is commercially available (BH) max =1.5MGOe plastic magnetic particles.

[0082] Comparative Example 2

[0083] The injection molding magnet material of this comparative example is commercially available (BH) max =1.6MGOe plastic magnetic particles.

[0084] Comparative Example 3

[0085] The injection molding magnet material of this comparative example is commercially available (BH) max =1.9MGOe plastic magnetic particles.

[0086] Comparative Example 4

[0087] The injection molding magnet material of this comparative example is commercially available (BH) max =2.0MGOe plastic magnetic particles, wherein the injection molded magnet materials of Comparative Examples 1-4 come from the same company.

[0088] Comparative Example 5

[0089] This comparative example provides an injection molding magnet material, and the raw materials include by weight: 86.5wt.% of ferrite powder, 6.10wt.% of binder A, 6.10wt.% of binder B, 2.10wt.% of coupling agent (total 101.35%, normalized coupling agent ratio 2.06%), 0.05wt.% of heat stabilizer, 0.5wt.% of lubricant, wherein the relative viscosity of binder A is 2.0, and the relative viscosity of binder B is 1.0. It should be noted that in the comparative example, the total proportion of all raw materials may be less than or more than 100%, but it does not affect the proportion between different raw materials.

[0090] The preparation method of the injection-molded magnet material is the same as that in Example 1, to obtain the injection-molded magnet material of this comparative example.

[0091] Comparative Example 6

[0092] This comparative example provides an injection molding magnet material, and the raw materials include, by weight: 87.6wt.%, ferrite powder, 5.52wt.%, binder A, 5.52wt.%, binder B, 0.76wt.%, coupling agent, 0.6wt.%, heat stabilizer (total 100.5%, normalized heat stabilizer ratio 0.59%), and lubricant 0.5wt.%, wherein the relative viscosity of binder A is 1.8, and the relative viscosity of binder B is 1.1.

[0093] The preparation method of the injection-molded magnet material is the same as that in Example 1, to obtain the injection-molded magnet material of this comparative example.

[0094] Comparative Example 7

[0095] This comparative example provides an injection molding magnet material, and the raw materials include, by weight: 89.4wt.%, 89.4wt.%, 4.75wt.%, 4.75wt.%, 0.75wt.%, 0.05wt.%, 1.2wt.% lubricant (total 100.9%, normalized lubricant percentage 1.19%), wherein the relative viscosity of binder A is 1.7, and the relative viscosity of binder B is 1.2.

[0096] The preparation method of the injection-molded magnet material is the same as that in Example 1, to obtain the injection-molded magnet material of this comparative example.

[0097] Comparative Example 8

[0098] This comparative example provides an injection molding magnet material, and the raw materials include, by weight: 90.5wt.%, ferrite powder, 2.46wt.%, binder A, 5.74wt.%, binder B, 0.75wt.%, coupling agent, 0.05wt.%, heat stabilizer, and 0.5wt.% lubricant, wherein the relative viscosity of binder A is 1.6, and the relative viscosity of binder B is 1.3.

[0099] The preparation method of the injection-molded magnet material is the same as that in Example 1, to obtain the injection-molded magnet material of this comparative example.

[0100] Comparative Example 9

[0101] This comparative example provides an injection molding magnet material, and the raw materials include, by weight: 90.5wt.%, ferrite powder, 5.74wt.%, binder A, 2.46wt.%, binder B, 0.75wt.%, coupling agent, 0.05wt.%, heat stabilizer, and 0.5wt.% lubricant, wherein the relative viscosity of binder A is 1.6, and the relative viscosity of binder B is 1.3.

[0102] The preparation method of the injection-molded magnet material is the same as that in Example 1, to obtain the injection-molded magnet material of this comparative example.

[0103] Comparative Example 10

[0104] The present embodiment provides an injection molding magnet material, wherein the raw materials include, by weight: 87.6 wt.%, ferrite powder, 10.85 wt.%, binder A, 0.75 wt.%, coupling agent, 0.30 wt.%, heat stabilizer, and 0.5 wt.% lubricant, wherein the relative viscosity of the binder A is 1.8.

[0105] The preparation method of the injection molding magnet material is the same as that of Example 4, to obtain the injection molding magnet material of this comparative example.

[0106] Comparative Example 11

[0107] The present embodiment provides an injection molding magnet material, wherein the raw materials include, by weight: 87.6 wt.%, ferrite powder, 10.85 wt.%, binder B, 0.75 wt.%, coupling agent, 0.30 wt.%, heat stabilizer, and 0.5 wt.% lubricant, wherein the relative viscosity of the binder B is 1.1.

[0108] The preparation method of the injection molding magnet material is the same as that of Example 4, to obtain the injection molding magnet material of this comparative example.

[0109] Comparative Example 12

[0110] The present embodiment provides an injection molding magnet material, wherein the raw materials include, by weight: 90.5wt.%, ferrite powder, 4.10wt.%, binder A, 4.10wt.%, binder B, 0.75wt.%, coupling agent, 0.05wt.%, heat stabilizer, and 0.5wt.% lubricant, wherein the relative viscosity of binder A is 1.6, and the relative viscosity of binder B is 1.4.

[0111] The preparation method of the injection molding magnet material is the same as that of Example 7 to obtain the injection molding magnet material of this comparative example.

[0112] Comparative Example 13

[0113] The present embodiment provides an injection molding magnet material, wherein the raw materials include, by weight: 87.6wt.%, ferrite powder, 6.78wt.%, binder A, 4.07wt.%, binder B, 0.75wt.%, coupling agent, 0.30wt.%, heat stabilizer, and 0.5wt.% lubricant, wherein the relative viscosity of binder A is 1.8, and the relative viscosity of binder B is 1.1.

[0114] The preparation method of the injection molding magnet material is the same as that of Example 4, to obtain the injection molding magnet material of this comparative example.

[0115] Comparative Example 14

[0116] The present embodiment provides an injection molding magnet material, wherein the raw materials include, by weight: 87.6wt.%, ferrite powder, 3.39wt.%, binder A, 7.46wt.%, binder B, 0.75wt.%, coupling agent, 0.30wt.%, heat stabilizer, and 0.5wt.% lubricant, wherein the relative viscosity of binder A is 1.8, and the relative viscosity of binder B is 1.1.

[0117] The preparation method of the injection molding magnet material is the same as that of Example 4, to obtain the injection molding magnet material of this comparative example.

[0118] The raw materials used for the injection molding magnet materials of Examples 1-11 and Comparative Examples 1-14 are summarized in Table 1 below, where the viscosity difference is the difference between the relative viscosity of binder A and the relative viscosity of binder B, and the content ratio is the ratio between the added weight of binder A and the added weight of binder B.

[0119] Table 1 Raw materials of injection molding magnet materials of Examples 1-11 and Comparative Examples 1-14

[0120]

[0121]

[0122] Test Example 1

[0123] The injection-molded magnet materials prepared in Examples 1-11 and Comparative Examples 1-14 were made into standard samples, the size of which was a Φ10×10 cylinder, and then the remanence (Br) and the maximum magnetic energy product (BH) were tested. max .

[0124] Test Example 2

[0125] The injection molded magnet materials prepared in Examples 1-11 and Comparative Examples 1-14 were made into standard specimens, and the tensile strength and impact strength of the materials were tested using a universal material testing machine and an impact testing machine, respectively. The test standard for tensile strength was GB / T1040-2006, and the test standard for impact strength was GB / T 1843-2008.

[0126] Test Example 3

[0127] The melt index (MFR) of the injection molded magnet materials prepared in Examples 1-11 and Comparative Examples 1-14 was tested using a melt indexer. The test conditions during the test were 270° C.×10 kg and the test standard was GB / T 3682.

[0128] Test Example 4

[0129] The injection molded magnet materials prepared in Examples 1-11 and Comparative Examples 1-14 were used to make hollow cylinders of Φ10.2×Φ5.3×9.2, and the changes in outer diameter dimensions after environmental testing were tested. Environmental testing was performed under the following experimental conditions: storage at 80±2°C and relative humidity of 90%-95% for 100 hours.

[0130] The test data of standard samples and standard specimens of magnetic materials prepared by this formula are summarized in Table 2. Among them, the hollow cylinder of Φ10.2×Φ5.3×9.2 has good appearance and stable size after high temperature and high humidity environment test, which can meet the requirements of use in high humidity environment. The price is compared with the injection molding magnet material of the same brand.

[0131] Table 2 Test results of injection molding magnet material properties of Examples 1-11 and Comparative Examples 1-14

[0132]

[0133]

[0134] Note: The price of the comparison sample with incorrect performance is meaningless, so it is not calculated.

[0135] Some of the embodiment data are as follows Figure 1 , Figure 2 As shown in the table and figure, the following data are analyzed:

[0136] (1) By comparing Examples 1-8 with Comparative Examples 1-4, since the content of magnetic powder added in the formula did not change, the binder PA12 was changed to two long carbon chain nylon post-injection magnet magnetic properties [Br, (BH) max ] Compared with the control example, there is almost no change, and the tensile strength and impact strength are basically unchanged; the size of the product after environmental testing changes very little, which is basically equivalent to PA12, with a change rate of less than 0.2%, and excellent dimensional stability. After PA12 is changed to two long carbon chain nylons, the injection molding magnet materials with grades of 1.5, 1.6, 1.9, and 2.0, the melt index of the injection molding magnet materials of Examples 1-8 is higher than 100g / 10min. Compared with Comparative Example 1, the melt index of Example 1 and Example 2 is increased by 44.6% and 89.14%, respectively. Compared with Comparative Example 2, the melt index of Example 3 and Example 4 is increased by 59.5% and 128.1%, respectively. Compared with Comparative Example 3, the melt index of Example 5 and Example 6 is increased by 50.6% and 120.1%, respectively. .8%, compared with comparative example 4, the melt index of embodiment 7 and embodiment 8 is increased by 84.4% and 144.6% respectively, that is to say, compared with the use of PA12, the melt index is increased by more than 44% after the use of long carbon chain nylon PA10T / X, and the increase ratios of different binders A and B are different. The fluidity of the injection molding magnet material in the preparation process is good, which is conducive to processing; in addition, after PA12 is changed to two long carbon chain nylons, the price reduction of the four alternative grades is between 10% and 16%, which reduces the material cost of the injection molding magnet material.

[0137] (2) Compared with Comparative Example 5, when the coupling agent is added in an excessive amount (>2 wt.%), the surface coverage of the magnetic powder is excessive, resulting in particle agglomeration and decreased dispersibility, thereby reducing the magnetic properties by 6.7% (from 1.5 MGOe to 1.4 MGOe); Compared with Comparative Example 6, when the heat stabilizer is added in an excessive amount (>0.5 wt.%), the incompatibility between the additive and the matrix is ​​increased, or the material structure becomes fragile due to excessive dispersion, thereby greatly reducing the mechanical properties, the tensile strength is reduced by 19.4% (from 60.26 MPa to 48.56 MPa), and the impact strength is reduced by 57.4% (33.41 kJ / m 2 →14.23kJ / m 2 ); Compared with Example 7, when the weight of lubricant added in Example 5 is too much (>1wt.%), the surface quality and glossiness of the product are reduced, the mechanical properties are weakened, and the dimensional expansion rate after the constant wet heat test increases to more than 0.2%. Therefore, the present invention limits the content of coupling agent in the raw material of the injection molding magnet material to 0.3-2wt.%, the content of heat stabilizer to 0.05-0.5wt.%, and the content of lubricant to 0.15-1wt.%.

[0138] (3) In Comparative Example 8, when the content of high-viscosity binder A is too low (<3wt.%), the mechanical properties of the injection-molded magnet material product are greatly reduced, and the fluidity is increased. Compared with Example 8, the tensile strength is reduced by 14.1% (from 54.36MPa to 46.71MPa), and the impact strength is reduced by 37% (16.25kJ / m 2 →10.24kJ / m 2 ); In comparative example 9, when the content of low-viscosity binder B is too small (<3wt.%), compared with Example 7 or Example 8, the mechanical properties of the product are improved, but the flowability is greatly reduced, only 56.71g / 10min, which does not meet the use requirements at all; therefore, the present invention limits the amount of raw material binders A and B in the injection molding magnet material to not less than 3wt.%,

[0139] (4) Compared with Example 10, Example 4 and Comparative Example 11, in Comparative Example 10, only the binder A with a higher viscosity was used, which caused the fluidity of the material to drop sharply to the point where it could not be measured. In addition, the poor fluidity directly resulted in the standard sample being not dense and failing to achieve the predetermined magnetic properties. (BH) max Only 1.38MGOe, compared with Example 4, the magnetic properties are reduced by 14% (from 1.604MGOe to 1.38MGOe); in Comparative Example 11, only the lower viscosity binder B is used, resulting in a sharp decrease in the mechanical properties of the material, and its impact strength is only 8.6kJ / m 2 Compared with Example 4, the impact strength decreased by 68.6% (27.42 kJ / m2 →8.6kJ / m 2 ), which completely fails to meet the use requirements; therefore, the present invention requires the use of both adhesive A and adhesive B, with the higher viscosity adhesive A providing mechanical properties and the lower viscosity adhesive B providing a high melt index, so that the use of a single adhesive cannot achieve the effect of the present invention.

[0140] (5) Compared with Example 7 and Comparative Example 12, the viscosity difference between the two adhesives in Comparative Example 12 is less than 0.3, resulting in varying degrees of decrease in its mechanical properties and magnetic properties, and the melt index is lower than 100g / 10min, which cannot meet the processing requirements. This is because when the difference between the two viscosities is less than 0.3, the following three situations will occur: ① Same high (both viscosities are greater than 1.5); ② Same medium (the two viscosities are 1.6 and 1.4); ③ Same low (both viscosities are less than 1.5); these three situations are basically equivalent to the use of a single adhesive mentioned in Comparative Examples 10 and 11 due to the small viscosity difference, and the final results are also basically equivalent. Therefore, it is necessary to control the relative viscosity of adhesive A and the relative viscosity of adhesive B to be no less than 0.3;

[0141] (6) Compared with Example 4 and Comparative Example 13, when the ratio of binder A to binder B is higher than 1:0.8 (equal to 1:0.6), although the fluidity of the material is greatly improved in Comparative Example 13, its mechanical properties and magnetic properties also show different proportions of decline, the magnetic properties are reduced by 10% (from 1.604MGOe→1.444MGOe), the tensile strength is reduced by 21.4% (from 56.41MPa→44.36MPa), and the impact strength is reduced by 55.2% (27.42kJ / m 2 →12.294 kJ / m 2 ); when the ratio of binder A to binder B is lower than 1:2 (equal to 1:2.2), the situation presented in Comparative Example 14 is exactly opposite to that of Comparative Example 13, and its tensile strength and magnetic properties are slightly increased, but the flow rate decreases too much, and the melt index is lower than 100g / 10min, which is reduced by 85.9% (287.52g / 10min→40.6g / 10min); therefore, the present invention limits the usage ratio of raw material binders A and B in the injection molding magnet material to between 1:0.8 and 2.

[0142] For those skilled in the art, when understanding the solutions described in the specific embodiments of the present invention, they can refer to the conventional technical manuals in the field. At the same time, for the places where the above-mentioned terms appear, they can make appropriate understandings or adjustments for reference, and deduce the implementation of the same or similar technical solutions without paying any creative work.

[0143] The above embodiments describe only the basic principles, main features and / or advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and the invention content of the specification only describe the principles or specific cases of the present invention. Without departing from the essence of the innovative idea of ​​the present invention, the innovative scheme of the present invention may be subject to various changes and improvements, and these changes and improvements all fall within the scope of protection claimed by the present invention.

Claims

1. An injection molding magnet material, characterized in that: The raw materials for preparing the injection molding magnet material include, by weight: Magnetic powder 80~92wt.%; Binder A 3-9wt.%; Binder B 3-9wt.%; Coupling agent 0.3-2wt.%; Additives 0.2~1.5wt.%; The binder A and the binder B are long carbon chain nylon PA10T / X, the relative viscosity of the binder A and the relative viscosity of the binder B are in the range of 1 to 2, and the difference between the relative viscosity of the binder A and the relative viscosity of the binder B is not less than 0.

3.

2. An injection-molded magnet material according to claim 1, characterized in that: The magnetic powder is any one of ferrite, neodymium iron boron, and samarium iron nitrogen, or a combination of at least two thereof. The ferrite includes at least one of strontium ferrite magnetic powder and barium ferrite magnetic powder.

3. The injection molding magnet material according to claim 1, characterized in that: Based on the molar percentage of PA10T / X, the content of 10T unit is 70-95 mol.%, and the content of X unit is 5-30 mol.%; wherein the X unit is a fatty chain, which is a straight chain or branched chain of 4 to 16 carbon atoms.

4. The injection molding magnet material according to claim 3, characterized in that: The X unit is a saturated fatty chain having 8 to 14 carbon atoms.

5. The injection molding magnet material according to claim 1, characterized in that: The auxiliary agents are a heat stabilizer and a lubricant. The content of the heat stabilizer is 0.05-0.5 wt.%, and the content of the lubricant is 0.15-1 wt.%.

6. The injection molding magnet material according to claim 1, characterized in that: The ratio of the added weight of the binder A to the added weight of the binder B is 1:0.8-2.

7. The injection molding magnet material according to claim 6, characterized in that: The ratio of the added weight of the binder A to the added weight of the binder B is 1:1 to 1.

5.

8. An injection molding magnet material according to any one of claims 1 to 7, characterized in that: The magnetic powder content in the injection molding magnet material is 86.5-90.5wt.%, the binder A content is 3.2-6.1wt.%, and the binder B content is 4.1-7.3wt.%. The ratio of the added weight of the binder A to the added weight of the binder B is 1:0.8-2.

9. A method for preparing an injection-molded magnet material according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, spraying the coupling agent onto the magnetic powder under stirring at 80-120° C., stirring, then adding the binder A, the binder B, and the auxiliary agent, and continuing to stir evenly at 80-120° C. to obtain a mixed material; S2. Add the obtained mixture into a twin-screw extruder, melt-extrude into wire at 220° C. to 280° C., cool, and pelletize to obtain an injection-molded magnet material.

10. An injection molded magnet, characterized in that: The magnet is obtained by injection molding using an injection molding magnet material according to any one of claims 1 to 8 through an injection molding machine.

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