Magnetic powder glue and preparation method thereof

Abstract

The invention relates to the technical field of magnetic powder glue, in particular to magnetic powder glue and a preparation method thereof.The magnetic powder glue is prepared from, by weight, 20-30 parts of special alkynyl epoxy resin; 5-10 parts of a curing agent; 40-60 parts of a solvent; 2-5 parts of a dispersing aid; the preparation method of the special alkynyl epoxy resin comprises the following steps: S1, mixing ethyoxyl propargyl alcohol, diethylene glycol butyl ether acetate and a DBE solvent, uniformly stirring, and keeping the temperature at 120-140 DEG C to obtain a reaction solution A; s2, uniformly mixing bisphenol F epoxy resin and 98% phosphoric acid to obtain a reaction solution B; s3, slowly dropwise adding the reaction liquid A into the reaction liquid B for three times, dropwise adding for 10-15 minutes each time, reacting for 2-2.5 hours after dropwise adding, cooling and discharging to obtain the special alkynyl modified epoxy resin. Through the synergistic effect of the special epoxy resin and the acidic dispersing aid, the magnetic powder is uniformly dispersed and firmly wrapped, and the agglomeration phenomenon is reduced.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of magnetic powder glue, in particular to a magnetic powder glue with excellent magnetic powder wrapping performance and a preparation method thereof, which is suitable for the fields of magnetic materials, electronic packaging, sensor manufacturing and the like. BACKGROUND

[0002] The magnetic powder glue is a functional adhesive for fixing magnetic particles and is widely applied to the fields of magnetic composite materials, electromagnetic shielding materials and the like. The traditional magnetic powder glue has problems of uneven dispersion of magnetic powder, poor wrapping performance, insufficient mechanical performance after curing and the like, which affect the performance of the final product.

[0003] In view of the related art, it is urgent to develop a magnetic powder glue with excellent magnetic powder wrapping performance, high stability and good curing performance. SUMMARY

[0004] The application provides a high-performance magnetic powder glue, which significantly improves the wrapping performance and dispersibility of the magnetic powder and guarantees the curing performance and mechanical strength of the adhesive by optimizing the formula combination.

[0005] The application provides a magnetic powder glue, which adopts the following technical scheme: A magnetic powder glue, by weight, comprises the following components: 20-30 parts of a special alkyne epoxy resin; 5-10 parts of a curing agent; 40-60 parts of a solvent; 2-5 parts of a dispersing aid; The preparation method of the special alkyne epoxy resin comprises the following steps: S1, ethoxypropynol, diethylene glycol butyl ether acetate and DBE solvent are mixed and uniformly stirred, the temperature is kept at 120-140 DEG C, and reaction liquid A is obtained; S2, bisphenol F epoxy resin and 98% phosphoric acid are uniformly mixed to obtain reaction liquid B; S3, reaction liquid A is slowly added to reaction liquid B in three times, the adding time is 10-15 minutes each time, after the adding is completed, the reaction is carried out for 2-2.5 h, the temperature is lowered to discharge, and the special alkyne modified epoxy resin is obtained.

[0006] As a preferred technical scheme of the application, the special alkyne epoxy resin has a molecular weight of 500-1000 and is soluble in a solvent.

[0007] As a preferred technical scheme of the application, the curing agent comprises one or a mixture of several kinds of amino curing agents and acid anhydride curing agents.

[0008] As a preferred technical solution of the present invention, the solvent includes one or a mixture of several of aromatic hydrocarbons, aliphatic hydrocarbons, ester cyclic hydrocarbons, esters, diol derivatives, alcohols, and ketones.

[0009] As a preferred technical solution of the present invention, the solvent is at least one selected from toluene, xylene, pentane, hexane, octane, cyclohexane, anhydrous ethanol, ethyl acetate, butyl acetate, amyl acetate, isopropanol, n-butanol, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, and propylene glycol methyl ether.

[0010] As a preferred technical solution of the present invention, the dispersing agent is a phosphate ester or sulfonic acid dispersant.

[0011] This invention also provides a method for preparing magnetic powder adhesive, comprising the following steps: S1. Mix the special acetylation epoxy resin with the solvent and stir until homogeneous; S2. Add the acidic dispersant and continue stirring for 10-20 minutes to ensure it is fully dissolved. S3. Add curing agent and mix evenly to obtain magnetic powder adhesive; In use, the active ingredients of the magnetic powder adhesive and the magnetic powder are mixed at a mass ratio of 2:98 and dispersed at high speed. Then, the solvent is removed, the mixture is pressed under normal pressure, and cured at high temperature to obtain a magnet for testing.

[0012] In summary, this application includes the following beneficial technical effects: Excellent magnetic powder encapsulation: Through the synergistic effect of special epoxy resin and acidic dispersant, the magnetic powder is uniformly dispersed and firmly encapsulated, reducing agglomeration.

[0013] Excellent curing performance: The selection of curing agents optimizes the curing speed and crosslinking density, improving the mechanical strength and heat resistance of the adhesive.

[0014] Wide range of applications: It can be used in fields such as magnetic composite materials, electromagnetic shielding materials, and sensor packaging. Detailed Implementation

[0015] The present application will be further described in detail below with reference to the embodiments.

[0016] This application discloses a magnetic powder adhesive, which, by weight, comprises the following components: 20-30 parts of special acetylation epoxy resin; 5-10 parts curing agent; 40-60 parts solvent; 2-5 parts dispersant; The preparation method of the special acetylene-based epoxy resin includes the following steps: S1. Mix ethoxypropynyl alcohol, diethylene glycol butyl ether acetate and DBE solvent, stir until homogeneous, and maintain the temperature at 120-140 degrees Celsius to obtain reaction solution A; S2. Mix bisphenol F epoxy resin and 98% phosphoric acid evenly to obtain reaction solution B; S3. Add reaction solution A slowly in 3 portions to reaction solution B, with each addition taking 10-15 minutes. After the addition is complete, react for 2-2.5 hours, cool down and discharge the material to obtain a special acetylene-modified epoxy resin.

[0017] The special alkynyl epoxy resin has a molecular weight of 500-1000 and is soluble in solvents; the curing agent includes one or a mixture of several amino curing agents and acid anhydride curing agents; the solvent includes one or a mixture of several aromatic hydrocarbons, aliphatic hydrocarbons, ester cyclic hydrocarbons, esters, glycol derivatives, alcohols, and ketones; the solvent is at least one of toluene, xylene, pentane, hexane, octane, cyclohexane, anhydrous ethanol, ethyl acetate, butyl acetate, amyl acetate, isopropanol, n-butanol, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, and propylene glycol methyl ether; the dispersing aid is a phosphate ester or sulfonic acid dispersant.

[0018] This invention also provides a method for preparing magnetic powder adhesive, comprising the following steps: S1. Mix the special acetylation epoxy resin with the solvent and stir until homogeneous; S2. Add the acidic dispersant and continue stirring for 10-20 minutes to ensure it is fully dissolved. S3. Add curing agent and mix evenly to obtain magnetic powder adhesive; In use, the active ingredients of the magnetic powder adhesive and the magnetic powder are mixed at a mass ratio of 2:98 and dispersed at high speed. Then, the solvent is removed, the mixture is pressed under normal pressure, and cured at high temperature to obtain a magnet for testing.

[0019] Preparation of special acetylene-modified epoxy resins: Component A: 1 part ethoxypropynyl alcohol; 30 parts diethylene glycol butyl ether acetate; 10 parts DBE mixed solvent; Component B: 100 parts of bisphenol F epoxy resin with a molecular weight of 500-1000; 0.5 parts of 98% phosphoric acid; 300 parts of diethylene glycol butyl ether acetate; 100 parts of DBE mixed solvent; Mix the required amount of component A in the formula until well combined and set aside. Stir the B component of the formula evenly, and add A dropwise to the B system in 4 portions, with each dropwise addition taking 10-15 minutes. After all the additions are completed, react for 2 hours, cool down and discharge the material to prepare a special acetylene-modified epoxy resin.

[0020] Examples and performance test results of magnetic powder adhesive formulation Table 1 Formulation Examples (parts by weight):

[0021] Table 2. Performance test results after magnetic powder mixing, drying, and pressing:

[0022] Permeability: Measured by impedance analyzer (frequency 1kHz). Loose packing density: tested according to the Ford-4 viscosity cup test; Flow rate: tested according to the viscosity cup test at -4. Unified instructions for experimental conditions: Magnetic powder type: Ferrite magnetic powder (average particle size 5μm); Curing conditions: 80℃ / 2h + 150℃ / 1h; Pressing process: 10MPa pressure molding, holding pressure for 5 minutes; Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that the amount of acidic dispersant BYK-110 added is 0.5 parts; Comparative Example 2: The difference between Comparative Example 2 and Example 2 is that the amount of amine curing agent is 2 parts; Comparative Example 3: The difference between Comparative Example 3 and Example 3 is that the acidic dispersant BYK-110 is replaced with the polymeric dispersant BYK-103; Comparative Example 4: The difference between Comparative Example 4 and Example 4 is that the alkynyl-modified epoxy resin is replaced with conventional bisphenol F epoxy resin. Table 3. Components of magnetic powder adhesives in Comparative Examples 1-4:

[0023] The properties of the magnetic powder adhesives obtained in Examples 1 to 4 were tested, and the results are shown in Table 4. Table 4 shows the properties of the nano-conductive adhesives prepared in Comparative Examples 1–5:

[0024] As can be seen from the results in Table 4: The magnetic powder adhesive prepared by the method of Comparative Example 1, after being mixed with magnetic powder, could not achieve a magnetic permeability of 120. This was because the amount of acidic dispersant was insufficient, resulting in insufficient encapsulation, which led to insufficient curing and low magnetic properties. The magnetic powder adhesive prepared by the method of Comparative Example 2, after being mixed with magnetic powder, could not achieve a magnetic permeability of 120 because there was too little curing agent, resulting in insufficient strength and a loose structure. Comparing Comparative Example 3 with Example 3, the magnetic permeability decreased after the acidic dispersant was replaced with a polymeric dispersant. This is because the dispersing effect of the polymeric dispersant is limited and cannot promote sintering. Comparing Comparative Example 4 with Example 4, when the acetylene-modified epoxy resin was replaced with ordinary epoxy resin without acetylene, the magnetic permeability could not reach 120. This is because the acetylene resin has a synergistic effect on the proximity of magnetic powder particles. If this reactivity is removed, the effect of reducing magnetic permeability when magnetic powder particles approach cannot be achieved. This invention provides a method for significantly improving the magnetic permeability of magnetic powder adhesive systems, thereby greatly reducing curing costs. It also saves material costs by reducing the amount of adhesive used.

[0025] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A magnetic powder adhesive, characterized by: By weight, it includes the following components: 20-30 parts of special acetylation epoxy resin; 5-10 parts hardener; 40-60 parts solvent; 2-5 parts dispersant; The preparation method of the special acetylene epoxy resin includes the following steps: S1. Mix ethoxypropynyl alcohol, diethylene glycol butyl ether acetate and DBE solvent, stir until homogeneous, and maintain the temperature at 120-140 degrees Celsius to obtain reaction solution A; S2. Mix bisphenol F epoxy resin and 98% phosphoric acid evenly to obtain reaction solution B; S3. Add reaction solution A slowly in 3 portions to reaction solution B, with each addition taking 10-15 minutes. After the addition is complete, react for 2-2.5 hours, cool down and discharge the material to obtain a special acetylene-modified epoxy resin.

2. The magnetic powder adhesive according to claim 1, characterized in that: The special acetylene-based epoxy resin has a molecular weight of 500-1000 and is soluble in solvents.

3. The magnetic powder adhesive according to claim 1, characterized in that: The curing agent includes one or a mixture of several of amino curing agents and acid anhydride curing agents.

4. The magnetic powder adhesive according to claim 1, characterized in that: The solvent includes one or a mixture of several of the following: aromatic hydrocarbons, aliphatic hydrocarbons, cycloalkenes, esters, diol derivatives, alcohols, and ketones.

5. The magnetic powder adhesive according to claim 4, characterized in that: The solvent is at least one of toluene, xylene, pentane, hexane, octane, cyclohexane, anhydrous ethanol, ethyl acetate, butyl acetate, amyl acetate, isopropanol, n-butanol, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, and propylene glycol methyl ether.

6. The method for preparing a magnetic powder adhesive according to claim 1, characterized in that: S1. Mix the special acetylation epoxy resin with the solvent and stir until homogeneous; S2. Add the acidic dispersant and continue stirring for 10-20 minutes to ensure it is fully dissolved. S3. Add curing agent and mix evenly to obtain magnetic powder adhesive; In use, the active ingredients of the magnetic powder adhesive and the magnetic powder are mixed at a mass ratio of 2:98 and dispersed at high speed. Then, the solvent is removed, the mixture is pressed under normal pressure, and cured at high temperature to obtain a magnet for testing.

7. The magnetic powder adhesive according to any one of claims 1-6 or the preparation method according to claim 7, characterized in that: Applications of the prepared magnetic powder adhesive in the field of magnetic materials.

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