Adhesive composition, soft magnetic composite material as well as preparation method and application of soft magnetic composite material

Abstract

The invention provides an adhesive composition, a soft magnetic composite material and a preparation method and application thereof, the adhesive composition comprises an adhesive and a curing agent, and the curing agent comprises a first curing agent, a second curing agent and a third curing agent. The adhesive composition provided by the invention has good adhesion, and the soft magnetic composite material prepared from the adhesive composition has the characteristics of high tensile strength, high magnetic conductivity, difficulty in cracking in a curing process and high resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of soft magnetic composite materials, and specifically relates to an adhesive composition, a soft magnetic composite material, and a preparation method and application thereof. Background Art

[0002] Soft magnetic composite materials are easily magnetized and demagnetized and are made into electronic components. They are widely used in photovoltaic, new energy, home appliances and other fields. With the rapid development of modern information technology, their demand is growing. Soft magnetic composite materials are usually composed of iron-based alloy powder, inorganic insulating coating layer and organic coating resin. The organic coating resin can play the dual functions of bonding and insulation, which has a great influence on the mechanical properties, thermodynamic properties and magnetic properties of the composite materials.

[0003] CN103666364A discloses an organic insulating binder for metal soft magnetic composite materials and a method for preparing metal soft magnetic composite materials. The organic insulating binder for metal soft magnetic composite materials consists of liquid A and liquid B, wherein liquid A is 0.2% to 0.6% of silane coupling agent, and liquid B is an insulating coating liquid mixed with a mass ratio of 10% to 30% alicyclic epoxy resin, 5% to 15% methyl hexahydrophthalic anhydride, 20% to 60% silicone resin and 10% to 40% xylene. The total amount of liquid B is 0.5% to 1.5%, and the above percentages of liquid A and liquid B are mass percentages of the mass of metal powder. The organic insulating binder for the metal soft magnetic composite material provided by this technical solution has the dual effects of insulation and bonding, and has good high temperature resistance, which is beneficial to increase the forming pressure and heat treatment temperature or reduce the content of the binder, thereby increasing the density and strength of the magnet and improving the magnetic permeability and power loss of the magnet under high frequency. However, when using it to prepare metal soft magnetic composite materials, it is necessary to use a silane coupling agent to treat the metal powder in advance, and the main component is liquid, the granulation process is relatively complicated, and the powder after granulation is wet, which is not suitable for large-scale mass production.

[0004] CN108630374A discloses a soft magnetic composite material for inductors and a preparation method thereof. The soft magnetic composite material includes the following components and the mass percentage of each component: 80% to 96% of soft magnetic powder, 2% to 10% of epoxy resin, 1% to 5% of curing agent, and 1% to 5% of release agent. The soft magnetic composite material for inductors provided by this technical solution has simple process and high production efficiency, but the epoxy value of the epoxy resin used is low, the type of curing agent is single, and the heat resistance of the formed inductor is poor, and it cannot be used in high temperature environment.

[0005] There are relatively few types of suitable mechanical coating resins in the prior art, most of which are not suitable for large-scale mass production. It is difficult to simultaneously meet the mechanical properties, thermodynamic properties and magnetic properties required by soft magnetic composite materials, and it is difficult to maintain good magnetic properties while meeting the mechanical strength requirements.

[0006] Therefore, it is necessary to develop an adhesive composition that meets the mechanical and magnetic property requirements of the soft magnetic composite material. Summary of the invention

[0007] In view of the shortcomings of the prior art, the present invention aims to provide an adhesive composition, a soft magnetic composite material, and a preparation method and application thereof. The adhesive composition has good adhesion, and the soft magnetic composite material prepared therefrom has good magnetic permeability, is not prone to cracking during the curing process, has high electrical resistance, and has good mechanical properties and magnetic comprehensive properties.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides an adhesive composition, comprising an adhesive and a curing agent, wherein the curing agent comprises a first curing agent, a second curing agent and a third curing agent.

[0010] In the present invention, the adhesive composition comprises an adhesive, a first curing agent, a second curing agent and a third curing agent, and the adhesive composition has good adhesion. When the adhesive composition is used to prepare a soft magnetic composite material, the soft magnetic powder flows more evenly, is fully filled, the adhesive curing process is progressive layer by layer, the curing process is not easy to crack, and a good curing effect is shown in each temperature range. The first curing agent enables the epoxy resin to better adhere to the surface of the soft magnetic powder during pre-curing at a lower temperature, which can increase toughness and improve resistance; the second curing agent makes the curing process smoother, promotes the molding of soft magnetic powder, and reduces the cracking of the soft magnetic composite material. In addition, the third curing agent, the strength after curing can be greater than the first curing agent and the second curing agent, and can improve the tensile strength. And the storage problem of soft magnetic composite material granules can also be solved by adjusting the material of the third curing agent, so that the storage time is longer. The adhesive composition is prepared by compounding an adhesive, a first curing agent, a second curing agent and a third curing agent, and the soft magnetic composite material prepared therefrom can have the characteristics of good tensile strength and high magnetic permeability, not easy to crack during the curing process, and high resistance.

[0011] Preferably, the difference between the curing temperature of the second curing agent and the curing temperature of the first curing agent is 20-60°C, for example, 23°C, 25°C, 27°C, 30°C, 33°C, 35°C, 37°C, 40°C, 43°C, 45°C, 47°C, 50°C, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C or 59°C, etc.

[0012] Preferably, the difference between the curing temperature of the third curing agent and the curing temperature of the second curing agent is 50-60°C, for example, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C or 59°C.

[0013] Preferably, the curing temperature of the first curing agent is lower than the curing temperature of the second curing agent, the curing temperature of the second curing agent is lower than the curing temperature of the third curing agent, and the difference between the curing temperature of the third curing agent and the curing temperature of the first curing agent is greater than 60°C, for example, 70°C, 80°C, 90°C, 100°C, 110°C or 120°C, etc.

[0014] Preferably, the difference between the curing temperature of the third curing agent and the curing temperature of the first curing agent is 80-200°C, for example, 100°C, 120°C, 140°C, 160°C or 180°C.

[0015] Preferably, the curing temperature of the first curing agent is greater than 60°C (for example, 65°C, 75°C, 80°C, 85°C or 90°C, etc.), and the curing temperature of the third curing agent is greater than 160°C (for example, 165°C, 170°C, 175°C, 180°C, 185°C or 190°C, etc.).

[0016] Preferably, the adhesive comprises epoxy resin.

[0017] Preferably, the epoxy resin includes any one of bisphenol A epoxy resin, bisphenol F epoxy resin or novolac epoxy resin, or a combination of at least two of them.

[0018] Preferably, the epoxy value of the epoxy resin is 0.2-0.5, for example, 0.2, 0.25, 0.3, 0.35, 0.4 or 0.45.

[0019] In the present invention, the epoxy value of the epoxy resin is preferably 0.2-0.5. If the epoxy value of the epoxy resin is too high, the epoxy resin exhibits liquid fluidity, which is not conducive to granulation, and is wet after granulation; if the epoxy value of the epoxy resin is too low, the epoxy resin has a low degree of crosslinking, which is not conducive to coating soft magnetic powder.

[0020] Preferably, the first curing agent includes any one of thiol, diethylenetriamine or polyamide 651, or a combination of at least two of them.

[0021] Preferably, the second curing agent comprises phthalic anhydride and / or methyltetrahydrophthalic anhydride.

[0022] Preferably, the third curing agent includes dicyandiamide and / or adipic acid dihydrazide.

[0023] Preferably, the mass ratio of the adhesive to the curing agent is 100:(15-25), for example, 100:16, 100:17, 100:18, 100:19, 100:20, 100:21, 100:22, 100:23 or 100:24, etc.

[0024] Preferably, based on the total mass of the curing agent as 100%, the mass of the first curing agent is 20% to 40% (for example, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36% or 38%, etc.), and more preferably 25% to 35%.

[0025] Taking the total mass of the curing agent as 100%, the mass of the second curing agent is 20% to 40% (for example, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36% or 38%, etc.), and more preferably 25% to 35%.

[0026] Taking the total mass of the curing agent as 100%, the mass of the third curing agent is 20% to 45% (for example, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42% or 44%, etc.), and more preferably 35% to 45%.

[0027] In a second aspect, the present invention provides a soft magnetic composite material, wherein raw materials for preparing the soft magnetic composite material include soft magnetic powder and the adhesive composition as described in the first aspect.

[0028] Preferably, the raw materials for preparing the soft magnetic composite material further include a release agent.

[0029] Preferably, the raw materials for preparing the soft magnetic composite material include the following components in parts by weight: 95 to 98 parts (for example, 95.5 parts, 96 parts, 96.5 parts, 97 parts or 97.5 parts, etc.) of soft magnetic powder, 2 to 5 parts (for example, 2.5 parts, 3 parts, 3.5 parts, 4 parts or 4.5 parts, etc.) of the adhesive composition as described in the first aspect, and 0.2 to 0.6 parts (for example, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts or 0.55 parts, etc.) of a release agent.

[0030] Preferably, the soft magnetic powder includes phosphating iron-silicon-chromium soft magnetic powder and / or phosphating iron-silicon-aluminum soft magnetic powder.

[0031] Preferably, the method for preparing the phosphated iron-silicon-chromium soft magnetic powder comprises the following steps: phosphating the iron-silicon-chromium soft magnetic powder with a phosphoric acid solution to obtain the phosphated iron-silicon-chromium soft magnetic powder.

[0032] Preferably, the mass percentage concentration of phosphoric acid in the phosphoric acid solution is 85% to 95% (eg, 86%, 88%, 90%, 92%, 94%, 96% or 98%, etc.).

[0033] Preferably, the mass ratio of the phosphoric acid to the iron-silicon-chromium soft magnetic powder is (0.1-0.3):100, for example, 0.13:100, 0.16:100, 0.19:100, 0.22:100, 0.25:100 or 0.28:100, etc.

[0034] Preferably, the method for preparing the phosphating Sendust soft magnetic powder comprises the following steps: phosphating the Sendust soft magnetic powder with a phosphoric acid solution to obtain the phosphating Sendust soft magnetic powder.

[0035] Preferably, the mass percentage concentration of phosphoric acid in the phosphoric acid solution is 85% to 95% (eg, 86%, 88%, 90%, 92%, 94%, 96% or 98%, etc.).

[0036] Preferably, the mass ratio of the phosphoric acid to the sendust soft magnetic powder is (0.1-0.3):100, for example, 0.13:100, 0.16:100, 0.19:100, 0.22:100, 0.25:100 or 0.28:100, etc.

[0037] Preferably, the D50 particle size of the FeSiCr soft magnetic powder and the FeSiAl soft magnetic powder is independently 5 to 15 μm, for example, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm or 14 μm.

[0038] Preferably, the release agent comprises zinc stearate and / or lithium stearate.

[0039] In a third aspect, the present invention provides a method for preparing the soft magnetic composite material as described in the second aspect, the preparation method comprising the following steps:

[0040] (1) mixing the adhesive composition according to the first aspect and an organic solvent to obtain a mixed solution;

[0041] (2) mixing the mixed solution obtained in step (1) with the soft magnetic powder, drying, and granulating to obtain soft magnetic composite material granules;

[0042] (3) pouring the soft magnetic composite material granules obtained in step (2) into a mold for compression molding and curing to obtain the soft magnetic composite material.

[0043] Preferably, the granulation in step (2) specifically includes mixing granulation with a release agent.

[0044] Preferably, the curing in step (3) includes a first curing, a second curing and a third curing performed sequentially.

[0045] Preferably, the first curing temperature is 80-90°C (eg, 81°C, 83°C, 85°C, 87°C or 89°C, etc.), and the time is 30-40 min (eg, 31 min, 33 min, 35 min, 37 min or 39 min, etc.).

[0046] Preferably, the temperature of the second curing is 120-130°C (eg, 121°C, 123°C, 125°C, 127°C or 129°C, etc.), and the time is 30-40 min (eg, 31 min, 33 min, 35 min, 37 min or 39 min, etc.).

[0047] Preferably, the temperature of the third curing is 180-190° C. (eg, 181° C., 183° C., 185° C., 187° C. or 189° C., etc.), and the time is 30-40 min (eg, 31 min, 33 min, 35 min, 37 min or 39 min, etc.).

[0048] In a fourth aspect, the present invention provides a use of the adhesive composition as described in the first aspect in wood bonding, plastic bonding or glass bonding.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] The adhesive composition of the present invention is prepared by compounding epoxy resin, a first curing agent, a second curing agent and a third curing agent, and has good bonding properties. The soft magnetic composite material granules prepared by the adhesive composition have a long storage time and can be stored for 3 months at room temperature. The prepared soft magnetic composite material has the characteristics of high tensile strength, high magnetic permeability, not easy to crack during the curing process, high resistance, and good mechanical properties and magnetic comprehensive properties. The soft magnetic composite material does not crack, has a tensile strength of ≥16.3kg, an initial magnetic permeability of 16.81-35.97H / m, and a resistance of ≥0.8GΩ. DETAILED DESCRIPTION

[0051] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0052] The sources of some components in the embodiments and comparative examples are as follows:

[0053] Bisphenol A epoxy resin, epoxy value 0.2-0.5, brand E50, manufacturer Baling Petrochemical;

[0054] Bisphenol F epoxy resin, epoxy value is 0.5, brand is F50, manufacturer is Dow;

[0055] Phenolic epoxy resin, epoxy value is 0.5, brand name is pne171, manufacturer is Tiantai;

[0056] Thiol: purchased from Aladdin official website;

[0057] Polyamide 651: purchased from Aladdin official website;

[0058] Phthalic anhydride: purchased from Aladdin official website;

[0059] Methyltetrahydrophthalic anhydride: purchased from Aladdin official website;

[0060] Adipic acid dihydrazide: purchased from Aladdin official website;

[0061] Dicyandiamide: purchased from Aladdin official website;

[0062] Release agent: zinc stearate, purchased from McLean's official website;

[0063] Anhydrous ethanol: purchased from Sinopharm Group.

[0064] Preparation Example 1

[0065] The present preparation example provides a phosphating iron-silicon-chromium soft magnetic powder, specifically a phosphating iron-silicon-chromium soft magnetic powder A. The phosphating iron-silicon-chromium soft magnetic powder A is prepared by the following method: mixing the iron-silicon-chromium soft magnetic powder (D50 particle size is 10 μm) and a phosphoric acid solution, wherein the mass percentage concentration of phosphoric acid in the phosphoric acid solution is 90%, the mass ratio of phosphoric acid to the iron-silicon-chromium soft magnetic powder is 0.2:100, stirring for 30 minutes, and drying at 80°C for 2 hours to obtain the phosphating iron-silicon-chromium soft magnetic powder A.

[0066] Preparation Example 2

[0067] The present preparation example provides a phosphating iron-silicon-chromium soft magnetic powder, specifically a phosphating iron-silicon-chromium soft magnetic powder B. The phosphating iron-silicon-chromium soft magnetic powder B is prepared by the following method: mixing the iron-silicon-chromium soft magnetic powder (D50 particle size is 5 μm) and a phosphoric acid solution, wherein the mass percentage concentration of phosphoric acid in the phosphoric acid solution is 90%, the mass ratio of phosphoric acid to the iron-silicon-chromium soft magnetic powder is 0.2:100, stirring for 30 minutes, and drying at 80°C for 2 hours to obtain the phosphating iron-silicon-chromium soft magnetic powder B.

[0068] Preparation Example 3

[0069] The present preparation example provides a phosphating iron-silicon-chromium soft magnetic powder, specifically a phosphating iron-silicon-chromium soft magnetic powder C. The phosphating iron-silicon-chromium soft magnetic powder C is prepared by the following method: mixing the iron-silicon-chromium soft magnetic powder (D50 particle size is 15 μm) and a phosphoric acid solution, wherein the mass percentage concentration of phosphoric acid in the phosphoric acid solution is 90%, the mass ratio of phosphoric acid to the iron-silicon-chromium soft magnetic powder is 0.2:100, stirring for 30 minutes, and drying at 80°C for 2 hours to obtain the phosphating iron-silicon-chromium soft magnetic powder C.

[0070] Example 1

[0071] The present embodiment provides an adhesive composition and a soft magnetic composite material and a preparation method thereof. The adhesive composition includes an epoxy resin (bisphenol A epoxy resin) and a curing agent in a mass ratio of 100:20. The curing agent includes a first curing agent (thiol), a second curing agent (phthalic anhydride) and a third curing agent (dicyandiamide). Taking the total mass of the curing agent as 100%, the mass of the first curing agent is 30%, the mass of the second curing agent is 30% and the mass of the third curing agent is 40%.

[0072] The raw materials for preparing the soft magnetic composite material include the following components in parts by weight: 96.5 parts of soft magnetic powder (phosphating iron-silicon-chromium soft magnetic powder A provided in Preparation Example 1), 3 parts of the above-mentioned adhesive composition and 0.5 parts of a release agent (zinc stearate).

[0073] The preparation method of the soft magnetic composite material is as follows:

[0074] (1) mixing a first curing agent, a second curing agent and a third curing agent, adding epoxy resin and dissolving them together in an organic solvent (anhydrous ethanol), wherein the mass ratio of the epoxy resin to the organic solvent is 1:4, to obtain a mixed solution;

[0075] (2) mixing the mixed solution obtained in step (1) with the soft magnetic powder, stirring thoroughly until the organic solvent is fully volatilized, drying in an oven at 50° C. for 40 min, mixing with a release agent after drying, and granulating to obtain soft magnetic composite material granules;

[0076] (3) pouring the soft magnetic composite material granules obtained in step (2) into a mold for pressing into a magnetic ring with an outer diameter of 17 mm, an inner diameter of 9.6 mm, and a height of 5 mm; after pressing, placing the magnetic ring in an oven for sequentially performing a first curing, a second curing, and a third curing; the first curing temperature is 80°C for 30 min, the second curing temperature is 130°C for 30 min, and the third curing temperature is 180°C for 30 min to ensure sufficient curing, thereby obtaining the soft magnetic composite material.

[0077] Example 2

[0078] This embodiment provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which differs from Embodiment 1 only in that the adhesive composition comprises an epoxy resin (bisphenol A epoxy resin) and a curing agent in a mass ratio of 100:17, and the curing agent comprises a first curing agent (thiol), a second curing agent (phthalic anhydride) and a third curing agent (dicyandiamide). Taking the total mass of the curing agent as 100%, the mass of the first curing agent is 28%, the mass of the second curing agent is 28% and the mass of the third curing agent is 44%, and other conditions are the same as those in Embodiment 1.

[0079] Example 3

[0080] This embodiment provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which differs from Embodiment 1 only in that the adhesive composition comprises an epoxy resin (bisphenol A epoxy resin) and a curing agent in a mass ratio of 100:25, and the curing agent comprises a first curing agent (thiol), a second curing agent (phthalic anhydride) and a third curing agent (dicyandiamide). Taking the total mass of the curing agent as 100%, the mass of the first curing agent is 32%, the mass of the second curing agent is 32% and the mass of the third curing agent is 36%, and other conditions are the same as those in Embodiment 1.

[0081] Example 4

[0082] This embodiment provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which differs from Example 1 only in that the first curing agent (thiol) is replaced with a first curing agent (diethylenetriamine) of the same mass, and other conditions are the same as Example 1.

[0083] Example 5

[0084] This embodiment provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which differs from Example 1 only in that the first curing agent (thiol) is replaced with a first curing agent (polyamide 651) of the same mass, and other conditions are the same as those in Example 1.

[0085] Example 6

[0086] This embodiment provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which differs from Example 1 only in that the second curing agent (phthalic anhydride) is replaced with a second curing agent of the same mass (methyltetrahydrophthalic anhydride), and other conditions are the same as Example 1.

[0087] Example 7

[0088] This embodiment provides a soft magnetic material binder and a soft magnetic composite material and a preparation method thereof, which differs from Example 1 only in that the high-temperature curing agent (dicyandiamide) is replaced with a high-temperature curing agent of the same mass (adipic acid dihydrazide), and other conditions are the same as Example 1.

[0089] Example 8

[0090] This embodiment provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which differs from Example 1 only in that the epoxy resin (bisphenol A epoxy resin) is replaced with an epoxy resin of the same quality (bisphenol F epoxy resin), and other conditions are the same as Example 1.

[0091] Example 9

[0092] This embodiment provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which differs from Example 1 only in that the epoxy resin (bisphenol A epoxy resin) is replaced with an epoxy resin of the same quality (phenolic epoxy resin), and other conditions are the same as Example 1.

[0093] Example 10

[0094] This embodiment provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which differs from Example 1 only in that the soft magnetic powder (phosphating iron-silicon-chromium soft magnetic powder A provided in Preparation Example 1) is replaced with a soft magnetic powder of the same mass (phosphating iron-silicon-chromium soft magnetic powder B provided in Preparation Example 2), and other conditions are the same as in Example 1.

[0095] Embodiment 11

[0096] This embodiment provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which differs from Example 1 only in that the soft magnetic powder (phosphating iron-silicon-chromium soft magnetic powder A provided in Preparation Example 1) is replaced with a soft magnetic powder of the same mass (phosphating iron-silicon-chromium soft magnetic powder C provided in Preparation Example 3), and other conditions are the same as in Example 1.

[0097] Example 12

[0098] This embodiment provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which differs from Example 1 only in that, based on the total mass of the curing agent being 100%, the mass of the first curing agent is 20%, the mass of the second curing agent is 40% and the mass of the third curing agent is 40%, and other conditions are the same as those in Example 1.

[0099] Embodiment 13

[0100] This embodiment provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which differs from Example 1 only in that, based on the total mass of the curing agent being 100%, the mass of the first curing agent is 40%, the mass of the second curing agent is 40% and the mass of the third curing agent is 20%, and other conditions are the same as those in Example 1.

[0101] Embodiment 14

[0102] This embodiment provides an adhesive composition and a soft magnetic composite material and a preparation method thereof. The only difference between this embodiment and Embodiment 1 is that the soft magnetic composite material granules obtained in step (2) are placed at room temperature (25°C) for 3 months before the preparation step (3) is carried out. Other conditions are the same as in Embodiment 1.

[0103] Comparative Example 1

[0104] This comparative example provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which differs from Example 1 only in that the curing agent does not include the first curing agent, and based on the total mass of the curing agent as 100%, the mass of the second curing agent is 42.8% and the mass of the third curing agent is 57.2%. The first curing agent is not added in the preparation method of the soft magnetic composite material, and other conditions are the same as those in Example 1.

[0105] Comparative Example 2

[0106] This comparative example provides an adhesive composition and a soft magnetic composite material and a preparation method thereof. The difference between this comparative example and comparative example 1 is that the soft magnetic composite material granules obtained in step (2) are placed at room temperature (25°C) for 3 months before the preparation step (3) is carried out. Other conditions are the same as those in comparative example 1.

[0107] Comparative Example 3

[0108] This comparative example provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which differs from Example 1 only in that the curing agent does not include the second curing agent, and based on the total mass of the curing agent as 100%, the mass of the first curing agent is 42.8% and the mass of the third curing agent is 57.2%. The second curing agent is not added in the preparation method of the soft magnetic composite material, and other conditions are the same as those in Example 1.

[0109] Comparative Example 4

[0110] This comparative example provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which differs from comparative example 3 only in that the soft magnetic composite material granules prepared in step (2) are placed at room temperature (25°C) for 3 months before the preparation step (3) is carried out, and other conditions are the same as those in comparative example 3.

[0111] Comparative Example 5

[0112] This comparative example provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which differs from Example 1 only in that the curing agent does not include a third curing agent, and based on the total mass of the curing agent being 100%, the mass of the first curing agent is 50% and the mass of the second curing agent is 50%. The third curing agent is not added in the preparation method of the soft magnetic composite material, and other conditions are the same as those in Example 1.

[0113] Comparative Example 6

[0114] This comparative example provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which differs from comparative example 5 only in that the soft magnetic composite material granules prepared in step (2) are placed at room temperature (25°C) for 3 months before the preparation step (3) is carried out, and other conditions are the same as those in comparative example 5.

[0115] Comparative Example 7

[0116] This comparative example provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which is different from Example 1 only in that the curing agent does not include the first curing agent and the second curing agent, and the first curing agent and the second curing agent are not added in the preparation method of the soft magnetic composite material, and other conditions are the same as Example 1.

[0117] Comparative Example 8

[0118] This comparative example provides an adhesive composition and a soft magnetic composite material and a preparation method thereof, which differs from Example 7 only in that the soft magnetic composite material granules obtained in step (2) are placed at room temperature (25°C) for 3 months before the preparation step (3) is carried out, and other conditions are the same as those in comparative example 7.

[0119] The soft magnetic composite materials provided in the above embodiments and comparative examples were tested, and the specific testing methods are as follows:

[0120] (1) Tensile strength: The soft magnetic composite material was placed on a tensile testing machine and slowly stretched at a stretching rate of 1 mm / min to test the tensile force at which the soft magnetic composite material broke.

[0121] (2) Cracking: Visually observe whether the prepared soft magnetic composite material is cracked.

[0122] (3) Magnetic permeability: The initial magnetic permeability at a test frequency of 100 kHz and a current of 0 A.

[0123] (4) Resistance: Test the resistance value under 100V voltage.

[0124] The test results are shown in Tables 1 and 2 below:

[0125] Table 1

[0126]

[0127] Table 2

[0128]

[0129] It can be seen from the contents of Table 1 and Table 2 that the soft magnetic composite materials provided by Examples 1 to 14 have good tensile strength, ranging from 16.3 to 20.1 kg; the initial magnetic permeability is relatively high, ranging from 16.81 to 35.97 H / m; the curing process is relatively smooth and not easy to crack, and has good storage stability; the resistance value is relatively high (0.8 to 1.6 GΩ), and has good mechanical properties and magnetic comprehensive properties.

[0130] Compared with Example 1, if the proportion of the first curing agent is relatively low (Example 12), the magnetic permeability and tensile strength of the prepared soft magnetic composite material increase but the resistance value decreases; if the proportion of the third curing agent is relatively low (Example 13), the resistance value of the prepared soft magnetic composite material increases but the magnetic permeability and tensile strength decrease; it can be seen that in the present invention, by controlling the mass ratio of the first curing agent, the second curing agent and the third curing agent within a specific range, the prepared soft magnetic composite material has better performance.

[0131] Compared with Example 1, if the first curing agent is not included (Comparative Example 1), the resistance value of the prepared soft magnetic composite material will be significantly reduced and it is easy to conduct.

[0132] Compared with Example 1, if the second curing agent is not included (Comparative Example 3), the prepared soft magnetic composite material cracks during the curing process and has low reliability.

[0133] Compared with Example 1, if the third curing agent is not included (Comparative Example 5), the prepared soft magnetic composite material has low magnetic permeability and poor tensile strength.

[0134] Compared with Example 1, if the first curing agent and the second curing agent are not included (Comparative Example 7), the prepared soft magnetic composite material has good tensile properties and magnetic permeability, but low electrical resistance and easy cracking.

[0135] Compared with Example 1, in Example 14, the soft magnetic composite material granules prepared in step (2) are placed at room temperature (25°C) for 3 months, and then the preparation step of step (3) is carried out. The tensile strength and magnetic permeability of the prepared soft magnetic composite material are slightly reduced; compared with Comparative Example 1, the tensile strength and magnetic permeability of the soft magnetic composite material prepared in Comparative Example 2 are slightly reduced; compared with Comparative Example 3, the tensile strength and magnetic permeability of the soft magnetic composite material prepared in Comparative Example 4 are slightly reduced; compared with Comparative Example 5, the tensile strength and magnetic permeability of the soft magnetic composite material prepared in Comparative Example 6 are significantly reduced, and the storage stability is poor; compared with Comparative Example 7, the tensile strength and magnetic permeability of the soft magnetic composite material prepared in Comparative Example 8 are slightly reduced. It can be seen that the addition of the third curing agent can improve the storage stability of the soft magnetic composite material granules.

[0136] The applicant declares that the present invention illustrates an adhesive composition, a soft magnetic composite material, and a preparation method and application thereof through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An adhesive composition, characterized in that The adhesive composition includes an adhesive and a curing agent, wherein the curing agent includes a first curing agent, a second curing agent and a third curing agent.

2. The adhesive composition according to claim 1, characterized in that The difference between the curing temperature of the second curing agent and the curing temperature of the first curing agent is 20 to 60° C.; Preferably, the difference between the curing temperature of the third curing agent and the curing temperature of the second curing agent is 50-60°C; Preferably, the curing temperature of the first curing agent is lower than the curing temperature of the second curing agent, the curing temperature of the second curing agent is lower than the curing temperature of the third curing agent, and the difference between the curing temperature of the third curing agent and the curing temperature of the first curing agent is greater than 60°C; Preferably, the curing temperature of the first curing agent is greater than 60°C, and the curing temperature of the third curing agent is greater than 160°C; Preferably, the adhesive comprises epoxy resin; Preferably, the epoxy resin includes any one of bisphenol A epoxy resin, bisphenol F epoxy resin or novolac epoxy resin or a combination of at least two thereof; Preferably, the epoxy value of the epoxy resin is 0.2 to 0.

5.

3. The adhesive composition according to claim 1 or 2, characterized in that The first curing agent includes any one of mercaptan, diethylenetriamine or polyamide 651 or a combination of at least two thereof; Preferably, the second curing agent comprises phthalic anhydride and / or methyltetrahydrophthalic anhydride; Preferably, the third curing agent includes dicyandiamide and / or adipic acid dihydrazide.

4. The adhesive composition according to any one of claims 1 to 3, characterized in that The mass ratio of the adhesive to the curing agent is 100:(15-25).

5. The adhesive composition according to any one of claims 1 to 4, characterized in that: Based on the total mass of the curing agent as 100%, the mass of the first curing agent is 20% to 40%, and more preferably 25% to 35%; Based on the total mass of the curing agent as 100%, the mass of the second curing agent is 20% to 40%, and more preferably 25% to 35%; Based on the total mass of the curing agent being 100%, the mass of the third curing agent is 20% to 45%, and more preferably 35% to 45%.

6. A soft magnetic composite material, characterized in that: The raw materials for preparing the soft magnetic composite material include soft magnetic powder and the adhesive composition according to any one of claims 1 to 5.

7. The soft magnetic composite material according to claim 6, characterized in that: The raw materials for preparing the soft magnetic composite material also include a release agent; The soft magnetic powder includes phosphating iron-silicon-chromium soft magnetic powder and / or phosphating iron-silicon-aluminum soft magnetic powder; Preferably, the method for preparing the phosphating iron-silicon-chromium soft magnetic powder comprises the following steps: phosphating the iron-silicon-chromium soft magnetic powder with a phosphoric acid solution to obtain the phosphating iron-silicon-chromium soft magnetic powder; Preferably, the mass percentage concentration of phosphoric acid in the phosphoric acid solution is 85% to 95%; Preferably, the mass ratio of the phosphoric acid to the iron-silicon-chromium soft magnetic powder is (0.1-0.3):100; Preferably, the method for preparing the phosphating Sendust soft magnetic powder comprises the following steps: phosphating the Sendust soft magnetic powder with a phosphoric acid solution to obtain the phosphating Sendust soft magnetic powder; Preferably, the mass percentage concentration of phosphoric acid in the phosphoric acid solution is 85% to 95%; Preferably, the mass ratio of the phosphoric acid to the sendust soft magnetic powder is (0.1-0.3):100; Preferably, the D50 particle sizes of the FeSiCr soft magnetic powder and the FeSiAl soft magnetic powder are each independently 5 to 15 μm.

8. A method for preparing the soft magnetic composite material according to claim 6 or 7, characterized in that: The preparation method comprises the following steps: (1) mixing the adhesive composition according to any one of claims 1 to 5 and an organic solvent to obtain a mixed solution; (2) mixing the mixed solution obtained in step (1) with the soft magnetic powder, drying, and granulating to obtain soft magnetic composite material granules; (3) pouring the soft magnetic composite material granules obtained in step (2) into a mold for compression molding and curing to obtain the soft magnetic composite material.

9. The preparation method according to claim 8, characterized in that: The organic solvent includes ethanol; Preferably, the granulation in step (2) specifically includes mixing and granulating with a release agent; Preferably, the curing in step (3) includes a first curing, a second curing and a third curing performed sequentially; Preferably, the first curing temperature is 80-90°C and the time is 30-40 minutes; Preferably, the second curing temperature is 120-130°C and the time is 30-40 minutes; Preferably, the third curing is performed at a temperature of 180 to 190° C. and for a time of 30 to 40 minutes.

10. Use of the adhesive composition according to any one of claims 1 to 5 in wood bonding, plastic bonding or glass bonding.

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