Functional magnetic powder and its manufacturing method, magnetic nylon raw particles and its manufacturing method, and magnetic plastic material

Abstract

The present application provides a functional magnetic powder and a manufacturing method thereof, magnetic nylon raw particles and a manufacturing method thereof, and a magnetic plastic material. The functional magnetic powder provided in the present application contains, by mass, 70 to 92 parts of magnetic powder, 0.1 to 1 part of an aminosilane coupling agent, and 0.1 to 1 part of a hydroxycarboxylic acid compound, where the hydroxycarboxylic acid compound is CH3(CH2OHCCH2OH). n It has a COOH structure, and n is an integer of 1 to 4. The functional magnetic powder provided in the present application is obtained by grafting a hydroxycarboxylic acid compound onto the magnetic powder using an aminosilane coupling agent, thereby obtaining a functional magnetic powder having functional groups such as hydroxyl groups, amide groups, methyl groups, and amino groups on the surface, and the large number of functional groups gives the functional magnetic powder and polymer excellent affinity and reactivity, which is advantageous for uniform dispersion of the functional magnetic powder in the polymer and further improves the strength and toughness of the polymer-based magnetic composite material in low-temperature environments.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to a Chinese patent application, application number 202210899899.X, entitled "Functional magnetic powder and manufacturing method thereof, magnetic nylon raw particles and manufacturing method thereof, and magnetic plastic material," filed with the State Intellectual Property Office of the People's Republic of China on July 28, 2022, the entire contents of which are incorporated herein by reference. [Technical Field]

[0002] The present application relates to the technical field of magnetic materials, and more particularly to functional magnetic powders and their manufacturing methods, magnetic nylon raw particles and their manufacturing methods, and magnetic plastic materials. [Background technology]

[0003] Polymer-based magnetic composites are composites made by mixing and processing magnetic powders with polymers. The magnetic powders typically used are strontium ferrite, barium ferrite, neodymium-iron-boron, etc., and the polymers typically used are nylon 6, nylon 12, polyphenylene sulfide, and epoxy resin. Compared to traditional sintered magnets, polymer-based magnetic composites offer advantages such as ease of processing, high precision, and toughness. Polymer-based magnetic composites also offer significant advantages in the fabrication of complex-shaped and integrally molded devices. Therefore, polymer-based magnetic composites are widely used in fields such as automobiles, home appliances, office supplies, and children's toys.

[0004] Compared to sintered magnets, polymer-based magnetic composites have the disadvantage of having poor magnetic properties. The main method for improving the magnetic properties of polymer-based magnetic composites is to select anisotropic magnetic powder and increase the magnetic powder filling rate (filling mass ratio 85% to 92%), but this reduces the melt fluidity of the composite material and further reduces the orientation movement of the anisotropic magnetic powder under an external magnetic field, thereby degrading the magnetic properties of the material.

[0005] With the development of society, the performance requirements for polymer-based magnetic composite materials are becoming increasingly higher, especially when applied in some low-temperature environments, such as the interiors of air conditioners and refrigerators, in the cold regions of Northeast Asia, and even in the transportation of coolants, liquid nitrogen, and liquid ammonia vapor, the toughness of polymer-based magnetic composite materials is reduced and the thermal expansion coefficient differs from that of the surrounding materials, causing the products to easily crack and even fall off.

[0006] Therefore, the present application is submitted. Summary of the Invention [Problem to be solved by the invention]

[0007] The main object of the present application is to provide a functional magnetic powder and a manufacturing method thereof, magnetic nylon raw particles and a manufacturing method thereof, and a magnetic plastic material, which solve the problems of a polymer-based magnetic composite material having reduced toughness in a low-temperature environment and having a product that easily cracks and falls off due to a difference in thermal expansion coefficient between the polymer-based magnetic composite material and the surrounding materials. [Means for solving the problem]

[0008] In order to achieve the above object, according to one aspect of the present invention, a functional magnetic powder is provided, and the raw materials of the functional magnetic powder include, by mass, 70 to 92 parts of magnetic powder, 0.1 to 1 part of an aminosilane coupling agent, and a hydroxycarboxylic acid compound, wherein the hydroxycarboxylic acid compound is CH3(CH2OHCCH2OH). n It has a COOH structure, and n is an integer of 1 to 4.

[0009] Furthermore, the hydroxycarboxylic acid compound is dihydroxymethylpropionic acid, and / or the aminosilane coupling agent includes at least one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminoethylaminopropyltrimethoxysilane, and γ-aminoethylaminopropyltriethoxysilane.

[0010] Furthermore, the material of the magnetic powder contains at least one of strontium ferrite, barium ferrite, neodymium-iron-boron, and samarium-iron-nitrogen, and / or the average particle size of the magnetic powder is 1 to 5 μm.

[0011] According to another aspect of the present application, there is further provided a method for producing a functional magnetic powder, the method comprising: step S1 of mixing a magnetic powder with an aminosilane coupling agent to carry out a coupling reaction to obtain a coupling agent-grafted magnetic powder, the coupling reaction temperature being preferably 60 to 120°C and the time being preferably 0.5 to 4 hours; and step S2 of mixing the coupling agent-grafted magnetic powder with a hydroxycarboxylic acid compound to carry out a graft reaction to obtain a functional magnetic powder, the graft reaction temperature being preferably 60 to 120°C and the time being preferably 0.5 to 4 hours; wherein the magnetic powder, aminosilane coupling agent, and hydroxycarboxylic acid compound have the same definitions as in the first aspect above, and therefore further explanation will be omitted here.

[0012] Furthermore, in step S1, it is preferable that an aminosilane coupling agent is first dispersed in a first solvent to obtain a solution of the aminosilane coupling agent, and then the solution of the aminosilane coupling agent and the magnetic powder are mixed to carry out a coupling reaction, and step S1 further includes a drying step set after the coupling reaction;

[0013] And / or, in step S2, a hydroxycarboxylic acid compound is first dispersed in a second solvent to obtain a solution of the hydroxycarboxylic acid compound, and then the solution of the hydroxycarboxylic acid compound is mixed with the coupling agent-grafted magnetic powder to carry out a graft reaction, and step S2 preferably further includes a drying step set after the graft reaction.

[0014] Furthermore, the first solvent and the second solvent are each independently a mixed solution of ethanol and water, and in the mixed solution of ethanol and water, the volume ratio of ethanol to water is preferably 90-95:10-5.

[0015] According to a third aspect of the present application, the present application provides magnetic nylon base particles, the raw materials of which comprise, by mass percentage, 70% to 94% functional magnetic powder and 6% to 30% nylon 12 elastomer, wherein the functional magnetic powder is any of the functional magnetic powders provided in the first aspect above or a functional magnetic powder obtained by any of the manufacturing methods provided in the second aspect above.

[0016] Furthermore, the raw material of the magnetic nylon raw particles further contains, by mass percentage, 0.3% to 10% of an auxiliary agent, and the auxiliary agent includes at least one of a compatibilizer, a lubricant, an antioxidant, and a plasticizer.

[0017] Furthermore, the compatibilizer is maleic anhydride grafted POE, and the mass content of the maleic anhydride grafted POE in the magnetic nylon raw particle raw material is 0.1% to 5%.

[0018] Furthermore, the lubricant is EVA wax, and the mass content of the EVA wax in the magnetic nylon raw particle raw material is 0.1% to 4%.

[0019] Furthermore, the antioxidant is antioxidant 1010, and the mass content of antioxidant 1010 in the magnetic nylon raw particles is 0.1% to 0.5%.

[0020] According to a fourth aspect of the present application, there is further provided a method for producing the above-mentioned magnetic nylon base granules, which method includes the steps of mixing raw materials for the magnetic nylon base granules, including a functional magnetic powder, a nylon 12 elastomer, and optional auxiliary agents, to obtain a raw material mixture, and extrusion-granulating the raw material mixture to obtain the magnetic nylon base granules.

[0021] Furthermore, extrusion granulation is carried out using a twin-screw extruder, and the extrusion granulation temperature is preferably 160 to 250°C.

[0022] According to a fifth aspect of the present application, there is further provided a magnetoplastic material, which is produced from any of the magnetic nylon base particles provided in the third aspect. [Effects of the Invention]

[0023] By applying the technical solution of the present application, the functional magnetic powder provided in the present application is obtained by grafting a hydroxycarboxylic acid compound onto the magnetic powder using an aminosilane coupling agent, thereby obtaining a functional magnetic powder having functional groups such as hydroxyl groups, amide groups, methyl groups and amino groups on the surface. The large number of functional groups gives the functional magnetic powder and polymer excellent affinity and reactivity, which is advantageous for the uniform dispersion of the functional magnetic powder in the polymer, and further improves the strength and toughness of the polymer-based magnetic composite material in a low-temperature environment, thereby preventing the occurrence of cracking and falling off of the product. DETAILED DESCRIPTION OF THE INVENTION

[0024] In addition, the embodiments and features of the embodiments in the present application may be combined with each other if there is no conflict. The present application will be described in detail below with reference to the embodiments.

[0025] As analyzed in the background art of this application, conventional polymer-based magnetic composite materials have technical problems in that they lose toughness in low-temperature environments and have thermal expansion coefficients that differ from those of their surrounding materials, causing the products to easily crack and even fall off. To solve these technical problems, this application provides functional magnetic powders and methods for producing same, magnetic nylon raw particles and methods for producing same, and magnetic plastic materials.

[0026] In a typical embodiment of the present application, a functional magnetic powder is provided, and the raw materials of the functional magnetic powder include, in parts by mass, 70 to 92 parts of magnetic powder, 0.1 to 1 part of an aminosilane coupling agent, and 0.1 to 1 part of a hydroxycarboxylic acid compound, wherein the hydroxycarboxylic acid compound is CH3(CH2OHCCH2OH). n It has a COOH structure, and n is an integer of 1 to 4.

[0027] The functional magnetic powder provided in the present application is obtained by grafting a hydroxycarboxylic acid compound onto the magnetic powder using an aminosilane coupling agent to obtain a functional magnetic powder having functional groups such as hydroxyl groups, amide groups, methyl groups, and amino groups on the surface. The large number of functional groups gives the functional magnetic powder and polymer excellent affinity and reactivity, which is advantageous for uniform dispersion of the functional magnetic powder in the polymer, and further improves the strength and toughness of the polymer-based magnetic composite material in low-temperature environments, preventing the occurrence of cracking and falling off of the product.

[0028] The type of magnetic powder is not limited, and may be any magnetic powder used in polymer-based magnetic composites, including, but not limited to, mixed magnetic powders consisting of one or more of strontium ferrite, barium ferrite, neodymium-iron-boron, or samarium-iron-nitrogen.

[0029] In order to further improve the uniformity of dispersion of the functional magnetic powder in the polymer, the average particle size of the magnetic powder is preferably 1 to 5 μm.

[0030] The type of the aminosilane coupling agent is not limited, and any aminosilane coupling agent having both an amino group and a siloxy group may be used, including, but not limited to, a mixed coupling agent consisting of one or more of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminoethylaminopropyltrimethoxysilane, and γ-aminoethylaminopropyltriethoxysilane.

[0031] The hydroxycarboxylic acid compound contains methyl, hydroxyl, and carboxyl groups, and the carboxyl groups can be coupled to the surface of the magnetic powder by reaction with the amino groups of the aminosilane coupling agent to form a functional magnetic powder having functional groups such as hydroxyl, amide, methyl, and amino groups on the surface. In the hydroxycarboxylic acid compound, n is an integer selected from 1, 2, 3, and 4.

[0032] In order to further improve the graft rate of the hydroxycarboxylic acid compound, n in the hydroxycarboxylic acid compound is preferably 1, that is, the hydroxycarboxylic acid compound is dihydroxymethylpropionic acid.

[0033] If too much aminosilane coupling agent is used, only a portion of the aminosilane coupling agent will be fully coupled to the magnetic powder, resulting in waste of the aminosilane coupling agent; if too little aminosilane coupling agent is used, the surface of the magnetic powder will not be able to couple to the aminosilane groups, resulting in less hydroxycarboxylic acid compound being grafted later, and therefore the functional groups on the surface of the functional magnetic powder will be too small to form good interactions and reactions with the polymer, and the strength and toughness of the polymer-based magnetic composite material in low-temperature environments will not be effectively improved. If too much hydroxycarboxylic acid compound is used, some of the hydroxycarboxylic acid compound will not be able to graft to the coupled magnetic powder, resulting in waste of the hydroxycarboxylic acid compound; if too little hydroxycarboxylic acid compound is used, the methyl groups, hydroxyl groups, and amide groups on the surface of the functional magnetic powder will be too few to form good interactions and reactions with the polymer. In the present application, the raw materials for producing the functional magnetic powder include, by mass, 70 to 92 parts of magnetic powder, 0.1 to 1 part of aminosilane coupling agent, and 0.1 to 1 part of hydroxycarboxylic acid compound, which improves the functional groups on the surface of the functional magnetic powder while reducing waste of raw materials, thereby improving the affinity and reactivity between it and the polymer.

[0034] Typically, but not exclusively, in the raw materials of the functional magnetic powder, the parts by weight of the magnetic powder are, for example, 70 parts, 72 parts, 75 parts, 78 parts, 80 parts, 82 parts, 85 parts, 88 parts, 90 parts, 92 parts, or a range value consisting of any two numbers; the parts by weight of the aminosilane coupling agent are, for example, 0.1 parts, 0.2 parts, 0.5 parts, 0.8 parts, 1 part, or a range value consisting of any two numbers; and the parts by weight of the hydroxycarboxylic acid compound are, for example, 0.1 parts, 0.2 parts, 0.5 parts, 0.8 parts, 1 part, or a range value consisting of any two numbers.

[0035] A second exemplary embodiment of the present application further provides a method for producing the above-mentioned functional magnetic powder, which includes step S1 of mixing a magnetic powder with an aminosilane coupling agent to carry out a coupling reaction to obtain a coupling agent-grafted magnetic powder, and step S2 of mixing the coupling agent-grafted magnetic powder with a hydroxycarboxylic acid compound to carry out a graft reaction to obtain a functional magnetic powder, wherein the magnetic powder, the aminosilane coupling agent, and the hydroxycarboxylic acid compound all have the same definitions as in the above-mentioned first exemplary embodiment.

[0036] The method for producing functional magnetic powder provided in the present application is a simple process, easy to operate, and adaptable to large-scale production, reducing production costs.

[0037] In the above step S1, in order to further improve the efficiency of the coupling reaction, the temperature of the coupling reaction is preferably 60 to 120° C. and the time is preferably 0.5 to 4 hours.

[0038] In the above step S1, in order to further promote the uniform mixing of the aminosilane coupling agent and the magnetic powder and further improve the efficiency of the coupling reaction, it is preferable to first disperse the aminosilane coupling agent in a first solvent to obtain a solution of the aminosilane coupling agent, and then mix the solution of the aminosilane coupling agent with the magnetic powder to carry out the coupling reaction.

[0039] To avoid the presence of the first solvent affecting the subsequent grafting reaction, it is preferable that step S1 further includes a drying step after the coupling reaction, in which the first solvent is removed by drying to obtain a coupling agent-grafted magnetic powder.

[0040] The mass concentration of the solution of the aminosilane coupling agent is not limited, and may be any mass concentration that allows for easy uniform mixing with the magnetic powder. From the viewpoint of environmental protection and cost, the first solvent is preferably a mixed solution of ethanol and water, and it is particularly advantageous for dispersing the aminosilane coupling agent when the volume ratio of ethanol to water in the first solvent is 90-95:10-5.

[0041] In the above step S2, in order to further improve the grafting efficiency, the grafting reaction temperature is preferably 60 to 120° C. and the time is preferably 0.5 to 4 hours.

[0042] In the above step S2, in order to further promote uniform mixing of the hydroxycarboxylic acid compound and the coupling agent-grafted magnetic powder and further improve grafting efficiency, it is preferable to first disperse the hydroxycarboxylic acid compound in a second solvent to obtain a solution of the hydroxycarboxylic acid compound, and then mix the solution of the hydroxycarboxylic acid compound with the coupling agent-grafted magnetic powder to carry out the grafting reaction.

[0043] In order to avoid the presence of the second solvent affecting the performance of the functional magnetic powder, it is preferable that the above step S2 further includes a drying step after the grafting reaction, in which the second solvent is removed by drying to obtain the functional magnetic powder.

[0044] The mass concentration of the solution of the hydroxycarboxylic acid compound is not limited, and may be any mass concentration that allows for easy uniform mixing with the aminosilane coupling agent. From the viewpoint of environmental protection and cost, the second solvent is preferably a mixed solution of ethanol and water, and it is particularly advantageous for the dispersion of the hydroxycarboxylic acid compound when the volume ratio of ethanol to water in the second solvent is 90-95:10-5.

[0045] Typically, but not limited to, in step S1, the temperature of the coupling reaction is, for example, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, or a range value consisting of any two values, and the time of the coupling reaction is, for example, 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, or a range value consisting of any two values, and in step S2, the temperature of the grafting reaction is, for example, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, or a range value consisting of any two values. The reaction temperature is, for example, 80°C, 90°C, 100°C, 110°C, 120°C, or a range formed from any two of these values; the grafting reaction time is, for example, 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, or a range formed from any two of these values; and the volume ratio of ethanol to water in the first and second solvents is, for example, 90:10, 91:9, 92:8, 93:7, 94:6, 95:5, or a range formed from any two of these values.

[0046] A third exemplary embodiment of the present application further provides magnetic nylon base particles, the raw materials of which contain, by mass percentage, 70% to 94% functional magnetic powder and 6% to 30% nylon 12 elastomer, wherein the functional magnetic powder is any of the functional magnetic powders provided in the first exemplary embodiment or any of the functional magnetic powders obtained by the manufacturing methods provided in the second exemplary embodiment.

[0047] The magnetic nylon base particles provided in this application are prepared by selecting a nylon 12 elastomer with a specific mass blending ratio and blending it with functional magnetic powder, so that the functional magnetic powder is uniformly dispersed in the nylon 12 elastomer, and the nylon and functional magnetic powder are bonded together by the hydroxyl groups, methyl groups, amino groups, and amide groups on the surface of the functional magnetic powder, thereby effectively improving the mechanical properties of the magnetic nylon base particles, which is beneficial in improving the strength and toughness of the magnetic plastic composite material produced from the magnetic nylon base particles at low temperatures and preventing the occurrence of shedding and cracking.

[0048] In order to further improve the processing performance of the magnetic nylon raw particles, it is preferable that the raw material of the magnetic nylon raw particles further contains 0.3% to 10% by mass of an auxiliary agent, and the type of auxiliary agent is not limited, and includes, but is not limited to, a mixing auxiliary consisting of one or more of a compatibilizer, a lubricant, an antioxidant, or a plasticizer.

[0049] In order to further improve the performance of the magnetic nylon base particles, it is preferable that the raw materials for the magnetic nylon base particles further contain, by mass percentage, 0.1% to 5% of a compatibilizer, 0.1% to 4% of a lubricant, 0.1% to 1% of a plasticizer, and 0.1 to 0.5% of an antioxidant.

[0050] The type of the compatibilizer is not limited, but maleic anhydride-grafted POE is preferred from the viewpoint of further improving the performance of the magnetic nylon base particles. The type of the lubricant is not limited, but EVA wax is preferred from the viewpoint of cost reduction. The type of the plasticizer is not limited, but pentaerythritol tetrastearate is preferred from the viewpoint of improving compatibility with nylon 12 elastomer. The type of the antioxidant is not limited, but antioxidant 1010 is preferred from the viewpoint of improving the processing efficiency of the magnetic nylon base particles.

[0051] Typically, but not exclusively, in the raw material of the magnetic nylon grains, the mass content of the functional magnetic powder is, for example, 70%, 70.2%, 72%, 75%, 78%, 80%, 82%, 85%, 88%, 90%, 92%, 94%, or a range value consisting of any two numerical values; the mass content of the nylon 12 elastomer is, for example, 6%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, or a range value consisting of any two numerical values; and the mass content of the selectable maleic anhydride-grafted POE is, for example, 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.5%, 2%. , 3%, 4%, 5%, or a range value consisting of any two numbers, the selectable mass content of EVA wax is, for example, 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, or a range value consisting of any two numbers, the selectable mass content of pentaerythritol tetrastearate is, for example, 0.1%, 0.2%, 0.5%, 0.8%, 1%, or a range value consisting of any two numbers, and the selectable mass content of antioxidant 1010 is, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or a range value consisting of any two numbers.

[0052] A fourth exemplary embodiment of the present application further provides a method for producing the above-mentioned magnetic nylon raw granules, the method including: mixing raw materials for the magnetic nylon raw granules, including a functional magnetic powder, a nylon 12 elastomer, and optional auxiliary agents, to obtain a raw material mixture; and extrusion-granulating the raw material mixture to obtain the magnetic nylon raw granules.

[0053] The method for producing magnetic nylon raw particles provided in the present application is a simple process, easy to operate, and applicable to industrial production, which is advantageous in reducing production costs.

[0054] To further improve the efficiency of extrusion granulation, it is preferable to use a twin-screw extruder for extrusion granulation.To further improve the production efficiency of magnetic nylon base granules, it is preferable that the extrusion granulation temperature is 160 to 250°C.

[0055] Typical, but non-limiting, extrusion temperatures are, for example, 160°C, 170°C, 180°C, 200°C, 220°C, 250°C, or any two ranges therebetween.

[0056] In a fifth exemplary embodiment of the present application, there is further provided a magnetoplastic material, wherein the magnetoplastic material is made from any of the magnetic nylon granules provided in the third exemplary embodiment.

[0057] The magnetoplastic material provided in this application is made from magnetic nylon raw particles. By blending functional magnetic powder with nylon 12 elastomer, the magnetoplastic material has excellent strength and toughness in low-temperature environments, effectively preventing cracking and shedding, and is expected to be widely used in low-temperature resistant parts for automobiles, home appliances, etc.

[0058] The excellent effects of the present invention will be further explained below with reference to examples and comparative examples.

[0059] All of the raw materials used in the following examples and comparative examples were commercially available.

[0060] Example 1 This example provides a functional magnetic powder, the raw materials of which include 70 kg of strontium ferrite magnetic powder (average particle size 1.5 μm), 0.8 kg of γ-aminopropyltriethoxysilane, and 0.5 kg of dihydroxymethylpropionic acid, which is produced according to the following steps: (1) 0.8 kg of γ-aminopropyltriethoxysilane was dispersed in a mixed solution of ethanol and water (the volume ratio of ethanol to water was 95:5) to obtain 10 kg of γ-aminopropyltriethoxysilane solution. (2) 0.5 kg of dihydroxymethylpropionic acid was dispersed in a mixed solution of ethanol and water (the volume ratio of ethanol to water was 95:5) to obtain 10 kg of dihydroxymethylpropionic acid solution; (3) 70 kg of strontium ferrite magnetic powder and 10 kg of γ-aminopropyltriethoxysilane solution were mixed in a mixer to carry out a coupling reaction. The temperature was set to 110°C and the rotation speed was set to 200 r / min. After the reaction for 2 hours, the mixture was dried to obtain a coupling agent-grafted magnetic powder. (4) The coupling agent grafted magnetic powder and 10 kg of dihydroxymethylpropionic acid solution were mixed at room temperature to carry out a graft reaction. After the reaction was carried out for 2 hours, the mixture was dried to obtain 71.3 kg of functional magnetic powder.

[0061] Example 2 This example provides a functional magnetic powder, the raw materials of which include 80 kg of strontium ferrite magnetic powder (average particle size 1.5 μm), 0.8 kg of γ-aminopropyltriethoxysilane, and 0.5 kg of dihydroxymethylpropionic acid. The manufacturing method is the same as that of Example 1, and the obtained functional magnetic powder weighs 81.3 kg.

[0062] Example 3 This example provides a functional magnetic powder, the raw materials of which include 90 kg of strontium ferrite magnetic powder (average particle size 1.5 μm), 0.6 kg of γ-aminopropyltriethoxysilane, and 0.5 kg of dihydroxymethylpropionic acid. The manufacturing method is the same as that of Example 1, and the obtained functional magnetic powder weighs 91.1 kg.

[0063] Example 4 This example provides a functional magnetic powder, the raw materials of which include 85 kg of neodymium-iron-boron magnetic powder (average particle size 100 μm), 0.8 kg of γ-aminopropyltriethoxysilane, and 0.5 kg of dihydroxymethylpropionic acid. The manufacturing method is the same as that of Example 1, and the obtained functional magnetic powder weighs 86.3 kg.

[0064] Example 5 This example provides a functional magnetic powder, the raw materials of which include 70 kg of strontium ferrite magnetic powder (average particle size 1.5 μm), 1 kg of γ-aminopropyltriethoxysilane, and 1 kg of dihydroxymethylpropionic acid. The manufacturing method is the same as that of Example 1, and the obtained functional magnetic powder weighs 72 kg.

[0065] Example 6 This example provides a functional magnetic powder, the raw materials of which include 92 kg of strontium ferrite magnetic powder (average particle size 1.5 μm), 0.1 kg of γ-aminopropyltriethoxysilane, and 0.1 kg of dihydroxymethylpropionic acid. The manufacturing method is the same as that of Example 1, and the obtained functional magnetic powder weighs 92.2 kg.

[0066] (Comparative Example 1) This comparative example provides a functional magnetic powder, the raw materials of which include 70 kg of strontium ferrite magnetic powder (average particle size 1.5 μm), 2 kg of γ-aminopropyltriethoxysilane, and 2 kg of dihydroxymethylpropionic acid, and the resulting functional magnetic powder weighs 74 kg.

[0067] (Comparative Example 2) This comparative example provides a functional magnetic powder, the raw materials of which include 70 kg of strontium ferrite magnetic powder (average particle size 1.5 μm), 0.05 kg of γ-aminopropyltriethoxysilane, and 0.05 kg of dihydroxymethylpropionic acid, and the resulting functional magnetic powder weighs 70.1 kg.

[0068] (Comparative Example 3) This comparative example provides a functional magnetic powder, the raw materials of which include 70 kg of strontium ferrite magnetic powder (average particle size 1.5 μm) and 0.8 kg of γ-aminopropyltriethoxysilane, without adding dihydroxymethylpropionic acid, and the resulting functional magnetic powder weighs 70.8 kg.

[0069] Example 7 This example provides magnetic nylon raw particles, the raw materials of which are 71.3 kg of functional magnetic powder produced in Example 1, 23 kg of nylon 12 elastomer, 3 kg of maleic anhydride grafted POE, 1.5 kg of EVA wax, 0.7 kg of pentaerythritol tetrastearate, and 0.5 kg of antioxidant 1010. The method for producing the magnetic nylon raw particles includes the following steps: (1) 71.3 kg of the functional magnetic powder prepared in Example 1, 23 kg of nylon 12 elastomer, 3 kg of maleic anhydride grafted POE, 1.5 kg of EVA wax, 0.7 kg of pentaerythritol tetrastearate, and 0.5 kg of antioxidant 1010 were added to a high-speed mixer, mixed at a speed of 300 r / min, and dried for 1 hour to obtain a raw material mixture. (2) The raw material mixture was mixed and extrusion-granulated in a twin-screw extruder, and the extrusion-granulation temperature was set to 220°C to obtain magnetic nylon base particles.

[0070] Example 8 This example differs from Example 7 in that the raw materials used in this example are 81.3 kg of the functional magnetic powder produced in Example 2, 14.7 kg of nylon 12 elastomer, 2 kg of maleic anhydride-grafted POE, 1 kg of EVA wax, 0.5 kg of pentaerythritol tetrastearate, and 0.5 kg of antioxidant 1010. The manufacturing method is the same as that of Example 7, and therefore a description thereof will be omitted here.

[0071] Example 9 This example differs from Example 7 in that the raw materials used in this example are 91.1 kg of the functional magnetic powder produced in Example 3, 6 kg of nylon 12 elastomer, 2 kg of maleic anhydride-grafted POE, 0.5 kg of EVA wax, 0.2 kg of pentaerythritol tetrastearate, and 0.2 kg of antioxidant 1010. The manufacturing method is the same as that of Example 7, and therefore a description thereof will be omitted here.

[0072] Example 10 This example differs from Example 7 in that the raw materials used in this example are 86.3 kg of the functional magnetic powder produced in Example 4, 10 kg of nylon 12 elastomer, 2 kg of maleic anhydride-grafted POE, 1 kg of EVA wax, 0.4 kg of pentaerythritol tetrastearate, and 0.3 kg of antioxidant 1010. The manufacturing method is the same as that of Example 7, and therefore a description thereof will be omitted here.

[0073] Example 11 This example differs from Example 7 in that the raw materials used in this example are 72 kg of the functional magnetic powder produced in Example 5, 22.2 kg of nylon 12 elastomer, 3 kg of maleic anhydride-grafted POE, 1.5 kg of EVA wax, 0.7 kg of pentaerythritol tetrastearate, and 0.6 kg of antioxidant 1010. The manufacturing method is the same as that of Example 7, and therefore a description thereof will be omitted here.

[0074] Example 12 This example differs from Example 7 in that the raw materials used in this example are 92.2 kg of the functional magnetic powder produced in Example 6, 6 kg of nylon 12 elastomer, 1 kg of maleic anhydride-grafted POE, 0.3 kg of EVA wax, 0.3 kg of pentaerythritol tetrastearate, and 0.1 kg of antioxidant 1010. The manufacturing method is the same as that of Example 7, and therefore a description thereof will be omitted here.

[0075] Comparative Example 4 This Comparative Example differs from Example 7 in that the raw materials used in this Comparative Example are 74 kg of the functional magnetic powder produced in Comparative Example 1, 21 kg of nylon 12 elastomer, 2 kg of maleic anhydride-grafted POE, 1.8 kg of EVA wax, 0.7 kg of pentaerythritol tetrastearate, and 0.5 kg of antioxidant 1010. The manufacturing method is the same as that of Example 7, and therefore a detailed description thereof will be omitted here.

[0076] (Comparative Example 5) This comparative example differs from Example 7 in that the raw materials used in this comparative example are 70.1 kg of the functional magnetic powder produced in Comparative Example 2, 24.9 kg of nylon 12 elastomer, 2 kg of maleic anhydride-grafted POE, 1.8 kg of EVA wax, 0.7 kg of pentaerythritol tetrastearate, and 0.5 kg of antioxidant 1010. The manufacturing method is the same as that of Example 7, and therefore a description thereof will be omitted here.

[0077] (Comparative Example 6) This comparative example differs from Example 7 in that the raw materials used in this comparative example are 70.8 kg of the functional magnetic powder produced in Comparative Example 3, 24.2 kg of nylon 12 elastomer, 2 kg of maleic anhydride-grafted POE, 1.8 kg of EVA wax, 0.7 kg of pentaerythritol tetrastearate, and 0.5 kg of antioxidant 1010. The manufacturing method is the same as that of Example 7, and therefore a detailed description thereof will be omitted here.

[0078] (Comparative Example 7) This example differs from Example 7 in that magnetic nylon raw particles are provided, and the raw materials are 61.3 kg of the functional magnetic powder produced in Example 1, 33 kg of nylon 12 elastomer, 3 kg of maleic anhydride-grafted POE, 1.5 kg of EVA wax, 0.7 kg of pentaerythritol tetrastearate, and 0.5 kg of antioxidant 1010.

[0079] (Comparative Example 8) This example differs from Example 7 in that magnetic nylon raw particles are provided, and the raw materials are 94 kg of the functional magnetic powder produced in Example 1, 3.3 kg of nylon 12 elastomer, 1.5 kg of maleic anhydride-grafted POE, 0.5 kg of EVA wax, 0.5 kg of pentaerythritol tetrastearate, and 0.2 kg of antioxidant 1010.

[0080] (Test Example 1) The magnetic nylon granules provided in Examples 7-12 and Comparative Examples 4-8 were injection-molded into 180mm x 13mm x 3mm injection-molded strips. The specific injection-molding process involved drying the magnetic nylon granules (100°C for 6 hours), placing them in an injection molding machine, and then injection-molding them into the corresponding mold at a temperature of 280°C and a pressure of 100MPa. After cooling, the injection-molded strips were obtained. Similar steps were followed to obtain injection-molded round cakes (φ25mm x 10mm) for magnetic property and low-temperature measurements.

[0081] The tensile strength and tensile breaking elongation of the injection molded strip, and the residual magnetic flux density Br, magnetic energy product (BH) max and the presence or absence of cracks at -60°C of the injection molded round cake were then detected, and the results are shown in Table 1 below.

[0082] Here, (1) the method for detecting the residual magnetic flux density Br and magnetic energy product (BH)max was to place the injection-molded round cake in a comprehensive magnetic property measuring device, apply a magnetic field to the injection-molded round cake, measure the induced magnetic field of the injection-molded round cake, and record the residual magnetic flux density and magnetic energy product output from the device.

[0083] (2) The method for detecting cracks at -60°C was to place the injection-molded round cake in a refrigerator at -60°C, take it out after one hour and place it in an oven at 100°C, take it out after one hour and place it in a refrigerator at -60°C, and cycle in this manner for 48 hours, after which it was observed whether the injection-molded round cake cracked.

[0084] [Table 1]

[0085] As can be seen from the above explanation, the above examples of the present application provide a functional magnetic powder provided by the present application in which a hydroxycarboxylic acid compound is grafted onto the magnetic powder using an aminosilane coupling agent, thereby obtaining a functional magnetic powder having functional groups such as hydroxyl groups, amide groups, methyl groups and amino groups on the surface. The multiple functional groups provide the functional magnetic powder and polymer with excellent affinity and reactivity, which is advantageous for uniform dispersion of the functional magnetic powder in the polymer. The polymer-based magnetic composite material produced from the obtained magnetic nylon base particles has excellent tensile strength and toughness in a low-temperature environment, thereby achieving the technical effect of effectively preventing the occurrence of cracking and shedding in the product.

[0086] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and variations to the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A functional magnetic powder, the raw material of which comprises, by mass, 70 to 92 parts of magnetic powder, 0.1 to 1 part of aminosilane coupling agent, and 0.1 to 1 part of hydroxycarboxylic acid compound, wherein the hydroxycarboxylic acid compound is CH ３ (CH ２ OHCCH ２ OH) ｎ COOH, and n is an integer of 1 to 4. A functional magnetic powder characterized by:

2. The hydroxycarboxylic acid compound is dihydroxymethylpropionic acid, and / or the aminosilane coupling agent contains at least one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminoethylaminopropyltrimethoxysilane, and γ-aminoethylaminopropyltriethoxysilane; The functional magnetic powder according to claim 1 .

3. The magnetic powder contains at least one of strontium ferrite, barium ferrite, neodymium-iron-boron, and samarium-iron-nitrogen, And / or the average particle size of the magnetic powder is 1 to 5 μm.

3. The functional magnetic powder according to claim 1 or 2.

4. A method for producing a functional magnetic powder, comprising: Step S1 of mixing a magnetic powder with an aminosilane coupling agent to carry out a coupling reaction to obtain a coupling agent-grafted magnetic powder, wherein the temperature of the coupling reaction is preferably 60 to 120°C and the time is preferably 0.5 to 4 hours; a step S2 of mixing the coupling agent-grafted magnetic powder with a hydroxycarboxylic acid compound to carry out a graft reaction to obtain the functional magnetic powder, wherein the temperature of the graft reaction is preferably 60 to 120°C and the time is preferably 0.5 to 4 hours; Here, the magnetic powder, the aminosilane coupling agent, and the hydroxycarboxylic acid compound have the same definitions as those described in any one of claims 1 to 3. A method for producing a functional magnetic powder.

5. In the step S1, the aminosilane coupling agent is first dispersed in a first solvent to obtain a solution of the aminosilane coupling agent, and then the solution of the aminosilane coupling agent and the magnetic powder are mixed to carry out the coupling reaction, and the step S1 preferably further includes a drying step set after the coupling reaction; and / or, in step S2, the hydroxycarboxylic acid compound is first dispersed in a second solvent to obtain a solution of the hydroxycarboxylic acid compound, and then the solution of the hydroxycarboxylic acid compound is mixed with the coupling agent-grafted magnetic powder to carry out a graft reaction, and step S2 preferably further includes a drying step set after the graft reaction; Preferably, the first solvent and the second solvent are each independently a mixed solution of ethanol and water, and in the mixed solution of ethanol and water, the volume ratio of ethanol to water is preferably 90 to 95:10 to 5. The method according to claim 4 .

6. Magnetic nylon raw particles, the raw material of which contains, by mass percentage, 70% to 94% of functional magnetic powder and 6% to 30% of nylon 12 elastomer, wherein the functional magnetic powder is the functional magnetic powder according to any one of claims 1 to 3 or the functional magnetic powder obtained by the manufacturing method according to claim 4 or 5. Magnetic nylon particles characterized by:

7. The raw material of the magnetic nylon raw particles further contains, in mass percentage, 0.3% to 10% of an auxiliary agent, and the auxiliary agent includes at least one of a compatibilizer, a lubricant, an antioxidant, and a plasticizer; Preferably, the compatibilizer is maleic anhydride-grafted POE, and the mass content of the maleic anhydride-grafted POE in the raw material of the magnetic nylon base particles is 0.1% to 5%; Preferably, the lubricant is EVA wax, and the mass content of the EVA wax in the raw material of the magnetic nylon raw particles is 0.1% to 4%; Preferably, the plasticizer is pentaerythritol tetrastearate, and the mass content of the pentaerythritol tetrastearate in the magnetic nylon raw particles is 0.1% to 1%; Preferably, the antioxidant is antioxidant 1010, and the mass content of the antioxidant 1010 in the magnetic nylon raw particles is 0.1% to 0.5%.

7. The magnetic nylon base particle according to claim 6.

8. The method includes the steps of: mixing raw materials for the magnetic nylon base particles, including the functional magnetic powder, the nylon 12 elastomer, and optional auxiliary agents, to obtain a raw material mixture; and extrusion-granulating the raw material mixture to obtain the magnetic nylon base particles.

8. The method for producing magnetic nylon raw particles according to claim 6 or 7.

9. The extrusion granulation is carried out using a twin-screw extruder, and the extrusion granulation temperature is preferably 160 to 250°C. The method according to claim 8 .

10. Produced from the magnetic nylon base particles according to claim 6 or 7. A magnetoplastic material characterized by:

Images