A high-performance rubber magnetic material and its preparation method

Abstract

The present invention provides a high-performance rubber magnetic material and a preparation method thereof, relating to the technical field of magnetic materials. The molecular formula of the magnetic material added in the high-performance rubber magnetic material is: Sm x Sr y Fe m Al n Co a O 19 , and the preparation method of the performance rubber magnetic material mainly includes steps such as mixing, ball milling, drying and modification, internal mixing, magnetic field injection molding, secondary magnetization, cross-linking and vulcanization treatment, etc. The present invention overcomes the deficiencies of the prior art. By optimizing the design of magnetic powder composition, microstructure, and adopting magnetic field forming technology in the preforming process for magnetic field forming and other technologies, a rubber magnetic material with high magnetic energy product and high coercivity is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic materials, and particularly relates to a high-performance rubber magnetic material and a preparation method thereof. Background Art

[0002] Traditional rubber magnetic materials are mainly made of ferrite magnetic powder, various types of rubber and additives through mixing and kneading, and then through processes such as extrusion molding, calendering molding, injection molding, magnetization, etc. to form flexible, elastic and distortable magnets, which can be applied to fields such as refrigerator magnets, rubber door seal magnetic strips, signal billboards, magnetic postcards, and home decoration building materials.

[0003] With the progress of technology and the trend of product renewal, the current market has higher and higher requirements for the magnetic properties of products. The magnetic properties have a great causal relationship with the composition of the product, the production process, and the magnetization method. How to optimize the composition of the product and improve the preparation method of the product to obtain a rubber magnet with high magnetic properties is of great significance.

[0004] The conventional rubber magnet production process generally involves conventional mixing of raw rubber, magnetic powder, and various compounding agents - preforming - vulcanization - magnetization [or magnetization before vulcanization] - final inspection and warehousing. The overall magnetic properties are relatively poor and cannot meet the increasing application requirements. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a high-performance rubber magnetic material and a preparation method thereof. By optimizing the design of the magnetic powder composition, the microstructure, and using magnetic field forming technology in the preforming process for magnetic field forming and other technologies, a rubber magnetic material with high magnetic energy product and high coercivity can be obtained.

[0006] To achieve the above objectives, the technical solution of the present invention is realized through the following technical solutions:

[0007] A high-performance rubber magnetic material, the molecular formula of the magnetic material added in the high-performance rubber magnetic material is: Sm x Sr y Fe m Al n Co a O 19 .

[0008] Preferably, in the high-performance rubber magnetic material, 0.12 ≤ x ≤ 0.46, 0.54 ≤ y ≤ 0.88, 10.70 ≤ m ≤ 10.93, 0.10 ≤ n ≤ 1.1, 0.12 ≤ a ≤ 1.2.

[0009] The preparation method of the high-performance rubber magnetic material includes the following steps:

[0010] (1) According to Sm x Sry Fe m Al n Co a O 19 Weigh the corresponding masses of yttrium nitrate, strontium nitrate, iron nitrate, aluminum nitrate, and cobalt nitrate mixtures according to the molecular formula of y - 19 . Then, mix the mixture with deionized water and citric acid evenly under the action of a magnetic stirrer. After that, continue stirring in a constant-temperature water bath to obtain a precursor for standby;

[0011] (2) Dry and sinter the above precursor to obtain an oxide powder. Mix and ball-mill the oxide powder with commercially available hydrogen-crushed N35 neodymium iron boron powder to obtain a mixed powder for standby;

[0012] (3) Dry the above mixed powder by blowing air to obtain a modified magnetic powder for standby;

[0013] (4) Put the above modified magnetic powder, chloroprene rubber, dioctyl phthalate, zinc oxide, silane coupling agent, and vulcanizing agent into a mixer to carry out rubber mixing to obtain a preform for standby;

[0014] (5) Heat the above preform to 160 °C under the protection of nitrogen, and then carry out magnetic field injection molding to obtain a molded rubber magnet;

[0015] (6) Carry out secondary magnetization on the above rubber magnet, and then carry out cross-linking vulcanization treatment with a vulcanizer to obtain a high-performance rubber magnetic material.

[0016] Preferably, in step (1), the mixing ratio of the mixture, deionized water, and citric acid is 1:6:1, and the way of stirring in a constant-temperature water bath is to stir in a constant-temperature water bath at 85 °C for 6 h under the action of a magnetic stirrer.

[0017] Preferably, in step (2), the way of drying and sintering is to dry in a forced-air drying oven at 85 °C for 8 h, and then put it into a muffle furnace for sintering treatment at 900 - 1150 °C for 3 - 8 h.

[0018] Preferably, in step (2), the mixing percentage of the oxide powder and the N35 neodymium iron boron powder is 58% - 96%:4% - 42%, and the way of grinding is to put it into a zirconia ball mill tank and carry out ball milling treatment for 4 - 10 h under the protection of anhydrous ethanol. The ball-to-powder ratio of zirconia balls to powder is 18 - 28:1, and the rotational speed of the ball mill is 250 rpm - 360 rpm.

[0019] Preferably, in step (3), the temperature of blowing air for drying is 85 °C, and the drying time is 2 h.

[0020] Preferably, in the step (4), the mass percentages of the components in the mixing are as follows: modified magnetic powder∶chloroprene rubber∶dioctyl phthalate∶zinc oxide∶silane coupling agent∶vulcanizing agent = 85.60%-91.09%∶5.8%-10.4%∶0.8%-1.1%∶0.9%-1.2%∶1.0%-1.3%∶0.31%-0.4%; and the mixing temperature is 160°C and the mixing time is 18 min.

[0021] Preferably, in the step (5), the magnetic field strength for magnetic field injection molding is 2.0 T.

[0022] Preferably, in the step (6), the magnetic field magnetization voltage for secondary magnetization is 350 V, the temperature for crosslinking vulcanization treatment is 170°C, and the treatment time is 120 s.

[0023] The present invention provides a high-performance rubber magnetic material and a preparation method thereof. Compared with the prior art, the advantages are as follows:

[0024] The present invention designs and optimizes the composition and ratio of each component in the rubber magnetic material, and effectively improves the magnetic properties of the rubber magnet, further improves its magnetic energy product and coercive force, and enhances the market application value of the overall material through the modification treatment of the magnetic powder and the application of the magnetic field forming process. Specific embodiments

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, rather than all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] Example 1:

[0027] Prepare a high-performance rubber magnetic material (select a material with the molecular formula of Sm 0.12 Sr 0.88 Fe 10.93 Al 0.75 Co 0.32 O 19 as the magnetic additive material):

[0028] (1) According to Sm 0.12 Sr 0.88 Fe 10.93 Al 0.75 Co 0.32 O 19Weigh corresponding masses of samarium nitrate, strontium nitrate, iron nitrate, aluminum nitrate, and cobalt nitrate as the mixed materials. Mix them evenly with deionized water and citric acid at a mass ratio of 1:6:1 under the action of a magnetic stirrer. Then place it in a constant temperature water bath at 85 °C and stir for 6 h under the action of a magnetic stirrer to obtain a precursor gel. Then put the precursor gel into a forced air drying oven and dry it at 85 °C for 8 h, and then put it into a muffle furnace and sinter it at 900 °C for 8 h to obtain the oxide Sm 0.12 Sr 0.88 Fe 10.93 Al 0.75 Co 0.32 O 19 powder;

[0029] (2) Put the above-mentioned oxide Sm 0.12 Sr 0.88 Fe 10.93 Al 0.75 Co 0.32 O 19 powder and the hydrogenated and crushed commercial N35 neodymium iron boron powder into a zirconia ball milling tank according to the mass percentage of 96%:4%, and carry out ball milling modification treatment under the protection of absolute ethanol. The ball milling time is 6 h, the ball-to-powder ratio of zirconia balls to powder is 18:1, and the rotational speed of the ball mill is 250 rpm to obtain a mixed powder;

[0030] (3) Put the above-mentioned mixed powder into a forced air drying oven and dry it at 85 °C for 2 h to obtain modified magnetic powder;

[0031] (4) According to the mass percentage, put the above-mentioned modified magnetic powder (89.04%), chloroprene rubber (7.6%), dioctyl phthalate (0.9%), zinc oxide (1.1%), silane coupling agent (1.0%), and vulcanizing agent (0.36%) into a mixer and knead at 160 °C for 18 min to obtain a preform;

[0032] (5) Heat the above-mentioned preform to 160 °C under nitrogen protection and immediately put it into a magnetic field injection molding press with a magnetic field strength of 2.0 T for magnetic field injection molding to obtain a molded rubber magnet;

[0033] (6) Use a magnetizer to perform secondary magnetic field magnetization on the above-mentioned molded rubber magnet, and the magnetic field magnetization voltage is 350 V;

[0034] (7) Use a vulcanizer to perform cross-linking vulcanization treatment on the rubber magnet after the above-mentioned secondary magnetization. The treatment process is 170 °C for 120 s to obtain a high-performance rubber magnetic material.

[0035] Example 2:

[0036] Prepare a high-performance rubber magnetic material (select the molecular formula Sm 0.35Sr 0.65 Fe 10.78 Al 1.1 Co 0.12 O 19 as a magnetic additive material):

[0037] (1) Weigh corresponding masses of samarium nitrate, strontium nitrate, iron nitrate, aluminum nitrate, cobalt nitrate, deionized water, and citric acid according to the chemical formula of Sm 0.35 Sr 0.65 Fe 10.78 Al 1.1 Co 0.12 O 19 and mix them evenly under the action of a magnetic stirrer according to a mass ratio of 1∶6∶1. Then place it in a constant temperature water bath at 85°C and stir for 6 h under the action of a magnetic stirrer. Then put the precursor gel into a forced air drying oven and dry it at 85°C for 8 h, and then put it into a muffle furnace and sinter it at 1050°C for 3 h to obtain the oxide Sm 0.35 Sr 0.65 Fe 10.78 Al 1.1 Co 0.12 O 19 powder;

[0038] (2) Put Sm 0.35 Sr 0.65 Fe 10.78 Al 1.1 Co 0.12 O 19 and the hydrogenated commercial N35 NdFeB powder into a zirconia ball milling tank according to a mass percentage of 82%∶18% and carry out ball milling treatment for 4 h under the protection of anhydrous ethanol. The ball-to-powder ratio of zirconia balls to powder is 25∶1, and the rotation speed of the ball mill is 280 rpm to obtain a mixed powder;

[0039] (3) Put the above mixed powder into a forced air drying oven and dry it at 85°C for 2 h to obtain modified magnetic powder;

[0040] (4) Mix the above modified magnetic powder (91.09%), chloroprene rubber (5.8%), dioctyl phthalate (0.8%), zinc oxide (0.9%), silane coupling agent (1.1%), and vulcanizing agent (0.31%) according to the mass percentage and put them into a mixer and knead them at 160°C for 18 min to obtain a preform;

[0041] (5) Heat the above preform to 160°C under nitrogen protection and immediately put it into a magnetic field injection molding press with a magnetic field strength of 2.0 T for magnetic field injection molding to obtain a molded rubber magnet;

[0042] (6) Use a magnetizer to perform secondary magnetic field magnetization on the above-mentioned formed rubber magnet, and the magnetic field magnetization voltage is 350V;

[0043] (7) Use a vulcanizer to perform cross-linking vulcanization treatment on the above-mentioned rubber magnet after secondary magnetization, and the treatment process is to treat at 170°C for 120s to obtain a high-performance rubber magnetic material.

[0044] Example 3:

[0045] Preparation of high-performance rubber magnetic material (select a material with the molecular formula Sm 0.46 Sr 0.54 Fe 10.70 Al 0.10 Co 1.2 O 19 as the magnetic additive material):

[0046] (1) According to Sm 0.46 Sr 0.54 Fe 10.70 Al 0.10 Co 1.2 O 19 Weigh the corresponding masses of samarium nitrate, strontium nitrate, iron nitrate, aluminum nitrate, cobalt nitrate, deionized water, and citric acid according to the molecular formula and stir and mix them evenly under the action of a magnetic stirrer. Then place it in a constant temperature water bath at 85°C and stir for 6h under the action of a magnetic stirrer to obtain a precursor gel; then put the precursor gel into a forced air drying oven and dry it at 85°C for 8h, and then put it into a muffle furnace and sinter it at 1150°C for 4h to obtain the oxide Sm 0.46 Sr 0.54 Fe 10.70 Al 0.10 Co 1.2 O 19 powder;

[0047] (2) Put Sm 0.46 Sr 0.54 Fe 10.70 Al 0.10 Co 1.2 O 19 and the hydrogenated and crushed commercial N35 powder into a zirconia ball milling tank and perform ball milling treatment for 10h under the protection of anhydrous ethanol. The ball-to-powder ratio of zirconia balls to powder is 28:1, and the rotational speed of the ball mill is 360 rpm to obtain a mixed powder;

[0048] (3) Put the above-mentioned mixed powder into a forced air drying oven and dry it at 85°C for 2h to obtain modified magnetic powder;

[0049] (4) Put the above-mentioned modified magnetic powder (85.60%), chloroprene rubber (10.4%), dioctyl phthalate (1.1%), zinc oxide (1.2%), silane coupling agent (1.3%), and vulcanizing agent (0.4%) into a mixer according to the mass percentage, and knead at 160 °C for 18 min to obtain a preform;

[0050] (5) Heat the above-mentioned preform to 180 °C under nitrogen protection, and immediately put it into a magnetic field injection molding press with a magnetic field strength of 2.0 T for magnetic field injection molding to obtain a molded rubber magnet;

[0051] (6) Use a magnetizer to perform secondary magnetic field magnetization on the above-mentioned molded rubber magnet, and the magnetic field magnetization voltage is 350 V;

[0052] (7) Use a vulcanizer to perform cross-linking vulcanization treatment on the rubber magnet after the above-mentioned secondary magnetization, and the treatment process is 170 °C for 120 s to obtain a high-performance rubber magnetic material.

[0053] Comparative Example 1:

[0054] Prepare a rubber magnetic material (select a material with the molecular formula Sm 0.12 Sr 0.88 Fe 10.93 Al 0.75 Co 0.32 O 19 as the magnetic additive material):

[0055] Step (1) is the same as that in Example 1;

[0056] (2) Put Sm 0.12 Sr 0.88 Fe 10.93 Al 0.75 Co 0.32 O 19 and the hydrogenated commercial N35 powder into a mixer according to a mass ratio of 96%:4% and mix evenly to obtain a mixed magnetic powder;

[0057] (3) Put the mixed magnetic powder (89.04%), chloroprene rubber (7.6%), dioctyl phthalate (0.9%), zinc oxide (1.1%), silane coupling agent (1.0%), and vulcanizing agent (0.36%) into a mixer according to the mass percentage, perform high-temperature kneading (160 °C, 18 min), then inject and mold without a magnetic field, and then use a magnetizer to perform magnetic field magnetization on the molded rubber magnet at a magnetic field magnetization voltage of 350 V; finally, use a vulcanizer to perform cross-linking vulcanization (170 °C, 120 s) on the magnetized rubber magnet to obtain a rubber magnet product.

[0058] Comparative Example 2:

[0059] Preparation of rubber magnetic material (selecting a material with the molecular formula Sm 0.35 Sr 0.65 Fe 10.78 Al 1.1 Co 0.12 O 19 as the magnetic additive material):

[0060] Step 1 is the same as in Example 2

[0061] (2) Put Sm 0.35 Sr 0.65 Fe 10.78 Al 1.1 Co 0.12 O 19 and the hydrogenated commercial N35 powder into a mixer according to the mass percentage of 82%:18% and mix evenly to obtain the mixed magnetic powder;

[0062] (3) Put the mixed magnetic powder (91.09%), chloroprene rubber (5.8%), dioctyl phthalate (0.8%), zinc oxide (0.9%), silane coupling agent (1.1%), and vulcanizing agent (0.31%) into a mixer according to the mass ratio, carry out high-temperature mixing (160 °C, 18 min), then inject and mold under no magnetic field, and then use a magnetizer to magnetize the molded rubber magnet at a magnetic field magnetization voltage of 350 V; finally, use a vulcanizer to cross-link and vulcanize the magnetized rubber magnet (170 °C, 120 s) to obtain the rubber magnet product.

[0063] Comparative Example 3:

[0064] Preparation of rubber magnetic material (selecting a material with the molecular formula Sm 0.46 Sr 0.54 Fe 10.70 Al 0.10 Co 1.2 O 19 as the magnetic additive material):

[0065] Step (1) is the same as in Example 3

[0066] (2) Put Sm 0.46 Sr 0.54 Fe 10.70 Al 0.10 Co 1.2 O 19 and the hydrogenated commercial N35 powder into a mixer according to the mass percentage of 58%:42% and mix evenly to obtain the mixed magnetic powder;

[0067] (3) Mix the mixed magnetic powder (85.60%), chloroprene rubber (10.4%), dioctyl phthalate (1.1%), zinc oxide (1.2%), silane coupling agent (1.3%), and vulcanizing agent (0.4%) according to the mass ratio, put them into a mixer, and after high-temperature mixing (160 °C, 18 min), inject and mold them without a magnetic field, and then use a magnetizer to magnetize the molded rubber magnet at a magnetic field magnetization voltage of 350 V; finally, use a vulcanizer to cross-link and vulcanize the magnetized rubber magnet (170 °C, 120 s) to obtain a rubber magnet product.

[0068] Detection:

[0069] Perform magnetic property tests on the rubber magnet products obtained in the above Examples 1-3 and Comparative Examples 1-3. The results are shown in the following table:

[0070]

[0071]

[0072] As can be seen from the above table, through the modification treatment of the magnetic powder and the application of the magnetic field forming process in the examples, the magnetic properties of the obtained rubber magnets are greatly improved compared with the comparative examples, and they have higher magnetic energy product and coercivity.

[0073] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0074] The above examples are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various examples of the present invention.

Claims

1. A high-performance rubber magnetic material, characterized in that, The molecular formula of the magnetic material added in the high-performance rubber magnetic material is: Sm 0.46 Sr 0.54 Fe 10.70 Al 0.10 Co 1.2 O 19 ; the preparation method of the high-performance rubber magnetic material comprises the following steps: (1) Weigh the corresponding masses of the mixed materials of samarium nitrate, strontium nitrate, iron nitrate, aluminum nitrate, and cobalt nitrate according to the molecular formula of 0.46 Sr 0.54 Fe 10.70 Al 0.10 Co 1.2 O 19 Then, stir and mix the mixed materials evenly with deionized water and citric acid under the action of a magnetic stirrer, and then continue to stir in a constant temperature water bath to obtain a precursor for standby; (2) drying and sintering the above-mentioned precursor to obtain an oxide powder, mixing and ball-milling the oxide powder with a hydrogenated commercial N35 neodymium iron boron powder to obtain a mixed powder for standby; (3) drying the above-mentioned mixed powder by blowing air to obtain a modified magnetic powder for standby; (4) putting the above-mentioned modified magnetic powder, chloroprene rubber, dioctyl phthalate, zinc oxide, silane coupling agent, and vulcanizing agent into a mixer to carry out rubber mixing to obtain a preform for standby; (5) heating the above-mentioned preform to 160 °C under the protection of nitrogen, and then carrying out magnetic field injection molding to obtain a molded rubber magnet; (6) carrying out secondary magnetization on the above-mentioned rubber magnet, and then carrying out cross-linking vulcanization treatment by using a vulcanizer to obtain a high-performance rubber magnetic material.

2. A high-performance rubber magnetic material according to claim 1, characterized in that: in the step (1), the mixing ratio of the mixture, deionized water, and citric acid is 1:6:1, and the way of constant temperature water bath stirring is to stir in a constant temperature water bath at 85 °C under the action of a magnetic stirrer for 6 h.

3. A high-performance rubber magnetic material according to claim 1, characterized in that: in the step (2), the drying and sintering method is to place it in a blast drying oven and dry at 85 °C for 8 h, and then put it into a muffle furnace and sinter at a temperature of 900 - 1150 °C for 3 - 8 h.

4. A high-performance rubber magnetic material according to claim 1, characterized in that: in the step (2), the mixing percentage of the oxide powder and the N35 neodymium iron boron powder is 58% - 96%:4% - 42%, and the grinding method is to put it into a zirconia ball mill tank and carry out ball milling treatment for 4 - 10 h under the protection of anhydrous ethanol, and the ball-to-material ratio of zirconia balls to powder is 18 - 28:1, and the rotational speed of the ball mill is 250 rpm - 360 rpm.

5. A high-performance rubber magnetic material according to claim 1, characterized in that: in the step (3), the temperature of blowing air drying is 85 °C, and the drying time is 2 h.

6. A high-performance rubber magnetic material according to claim 1, characterized in that: in the step (4), the mass percentages of each component in the mixer are: modified magnetic powder:chloroprene rubber:dioctyl phthalate:zinc oxide:silane coupling agent:vulcanizing agent = 85.60% - 91.09%:5.8% - 10.4%:0.8% - 1.1%:0.9% - 1.2%:1.0% - 1.3%:0.31% - 0.4%; and the temperature of mixing is 160 °C, and the mixing time is 18 min.

7. A high-performance rubber magnetic material according to claim 1, characterized in that: in the step (5), the magnetic field strength of the magnetic field injection molding is 2.0 T.

8. A high-performance rubber magnetic material according to claim 1, characterized in that: in the step (6), the magnetic field magnetization voltage of the secondary magnetization is 350 V, the temperature of the cross-linking vulcanization treatment is 170 °C, and the treatment time is 120 s.

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