Composite wiring board material and method for manufacturing the same

Abstract

The application relates to a composite circuit board material and a preparation method thereof, which comprises an electromagnetic shielding layer, a magnetic medium layer, a conductive layer and an insulating protective layer; the magnetic medium layer is prepared from a magnetic medium glue solution and a supporting body. The application has excellent electromagnetic shielding effect and good magnetic and conductive capacity, can effectively improve the electromagnetic compatibility of products, makes the use of products safer, and can reduce the overall thickness of the material as the power receiving coil base material of a wireless charging module, so that the electronic product is lighter and thinner.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electronic materials, and particularly relates to a composite circuit board material and a preparation method thereof. BACKGROUND

[0002] The wireless charger is a charger without connecting to the terminal device to be charged by the traditional charging power line. At present, wireless charging has been widely applied in the field of personal mobile electronic devices, mainly using electromagnetic induction technology. The wireless charging module is basically divided into the following modules: current converter, frequency converter, power output coil, power receiving coil, rectifier circuit and battery. The power receiving coil is the core component in the mobile electronic device, which is mainly composed of the following parts: induction coil, shielding layer and magnetic conductor. The induction coil is usually processed from a flexible circuit board (FPC), the magnetic conductor is usually a nanocrystalline panel or a ferrite magnetic plate, and the shielding layer is a metal composite material. The three are processed and then assembled together, and the process is relatively complicated, the cost is relatively high, and it is not conducive to the light and thin of the product. Therefore, it is of great significance to develop a composite material with good electrical conductivity, magnetic conductivity and electromagnetic shielding effect for reducing production cost and accelerating product miniaturization. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a composite circuit board material and a preparation method thereof. The composite circuit board material has excellent electromagnetic shielding effect and good magnetic conductivity and electrical conductivity, which can effectively improve the electromagnetic compatibility of the product, make the use of the product safer, and as the basic material of the power receiving coil of the wireless charging module, can reduce the overall thickness of the material, so that the electronic product is lighter and thinner.

[0004] The present application provides a composite circuit board material, which comprises an electromagnetic shielding layer, a magnetic medium layer, a conductive layer and an insulating protective layer. The magnetic medium layer is prepared from a magnetic medium glue solution and a supporting body. The powder used in the magnetic medium glue solution has a D 50 0.3 μm < D 50 < 0.5 μm, D 90 0.6 μm < D 90 < 1.0 μm.

[0005] Preferably, the material (also referred to as electromagnetic shielding material) used in the electromagnetic shielding layer is a metal material, a metal composite material or a metalized polymer material. The metalized polymer material includes metalized polyester (PET), polyimide (PI), polypropylene (PP), high-density polyethylene (HDPE), polyphenylene sulfide (PPS) or polyamide (PA). The thickness of the electromagnetic shielding layer is 5-50 μm, and the area is larger than that of the magnetic medium layer and the conductive layer.

[0006] Preferably, the magnetic permeable material used in the magnetic medium layer comprises one or more of zinc ferrite, nickel ferrite, manganese zinc ferrite, nickel zinc ferrite, copper zinc ferrite, and metal magnetic powder material. The magnetic permeability of the magnetic medium layer is 100-2000 H / m; the thickness of the magnetic medium layer is 30-50 μm.

[0007] Preferably, the conductive layer material is copper, and the conductive layer is fixed to the side of the magnetic medium layer away from the electromagnetic shielding layer; the thickness of the conductive layer is 35-105 μm.

[0008] Preferably, the insulating protective layer material is PET, PI, or PP.

[0009] Preferably, the support body is a polymer film subjected to plasma surface activation treatment. The polymer film is PI or PET, and the plasma treatment medium can be oxygen, argon, or nitrogen.

[0010] The present application also provides a preparation method of the composite circuit board material, comprising the following steps:

[0011] (1) preparing a magnetic medium powder; then subjecting the magnetic medium powder to surface modification using an organic alcohol solution as a solvent and a surfactant as a modifier; and then washing and multi-stage filtering the surface-modified magnetic medium powder;

[0012] (2) adding a dispersant to a solvent and mixing and stirring, then adding the magnetic medium powder obtained in step (1) and mixing and stirring uniformly, and finally adding a binder to obtain a magnetic medium glue solution;

[0013] (3) uniformly spraying the magnetic medium glue solution obtained in step (2) on both sides of the support body, then performing baking; then hot-pressing a protective film on the outer surfaces of the magnetic medium glue solutions on both sides, and finally sputtering copper on the outer surface of the protective film to obtain a magnetic medium layer; (4) electroplating a copper layer on one side of the magnetic medium layer obtained in step (3) as a conductive layer, and electroplating an electromagnetic shielding material on the other side; adhering an insulating protective film to the outer surface of the conductive layer and performing solidification treatment to obtain an insulating protective layer, thereby obtaining the composite circuit board material.

[0014] Preferably, the preparation method of the magnetic medium powder in step (1) comprises one or more of high-energy ball milling, hydrolysis precipitation, solvothermal method, hydrothermal method, and sol-gel method. If the preparation method is high-energy ball milling, hydrolysis precipitation, or sol-gel method, subsequent annealing treatment must be combined, with an annealing temperature of 300-600 ℃ and an annealing time of 2-5 h.

[0015] Preferably, the organic alcohol in step (1) includes one or more of ethanol, ethylene glycol, diethylene glycol, glycerol, pentaerythritol, neopentyl glycol, 1,4-butanediol. The mass ratio of alcohol to water in the organic alcohol solution is less than 1 and greater than 0.5.

[0016] Preferably, the surfactant in step (1) includes one or more of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, sodium pyrophosphate, sodium polyacrylate.

[0017] Preferably, the amount of magnetic medium powder in step (1) is 20-50 g / L, and the amount of surfactant is 0.01-0.5 g / L.

[0018] Preferably, the surface modification in step (1) lasts for 15-60 min; air is continuously supplied and stirring is continuously performed during the surface modification.

[0019] Preferably, the solvent in step (2) is pure water.

[0020] Preferably, the dispersant in step (2) includes one or more of carboxymethyl cellulose, gum gur, sodium tripolyphosphate. The mass ratio of dispersant to binder is 1:2-1:8, and the dispersant accounts for 1%-5% of the total mass of the magnetic medium glue solution.

[0021] Preferably, the binder in step (2) includes one or more of styrene-butadiene rubber emulsion, polyvinyl alcohol, polymethyl methacrylate emulsion, thermoplastic polypropylene emulsion, polyvinyl acetate emulsion.

[0022] Preferably, the stirring speed for adding the solvent in step (2) is 200-1000 rpm, and the duration is 10-30 min. The stirring speed for adding the magnetic medium powder is 30-1000 rpm, and the duration is 20-60 min. The stirring speed for adding the binder is 1000-2000 rpm, and the duration is 10-20 min.

[0023] Preferably, the viscosity of the magnetic medium glue solution in step (2) is 2000-3000 mPa·s, the solid content is 35-65%, and the vacuum screening is ≤200 mesh.

[0024] Preferably, the uniform spraying of the magnetic medium glue solution in step (3) has a single-sided density of 30-50 mg / cm 2 .

[0025] Preferably, the baking temperature in step (3) is 80-100°C, and the baking time is 15-40 min.

[0026] Preferably, the protective film in step (3) is preferably PI, the pressure of the hot pressing is 200-400 psi, and the temperature of the hot pressing is 130-200 DEG C.

[0027] Preferably, a glue layer is further arranged between the protective film and the magnetic medium glue solution in step (3). The glue layer is a TPI glue layer to increase the adhesion of the protective film.

[0028] Preferably, the copper thickness of the metal copper in step (3) is 10-40 nm.

[0029] Preferably, the process parameters of the electroplated metal copper layer in step (4) are: the direct current density is 10-60 A / dm 2 , the copper ion content in the electrolyte is 50-90 g / L, and the acid concentration is 90-130 g / L.

[0030] Preferably, the adhesive used for the adhesive insulating protective film in step (4) is one or more of epoxy adhesives, polyester adhesives, acrylic adhesives, and polyurethane adhesives.

[0031] Advantages

[0032] (1) The application has excellent electromagnetic shielding effect and good magnetic and electric conductivity, can effectively improve the electromagnetic compatibility of products, make the use of products safer, and can reduce the overall thickness of materials as the power receiving coil base material of the wireless charging module, so that the electronic finished product is lighter and thinner.

[0033] (2) The application obtains magnetic medium powder with excellent paramagnetism by strictly controlling the particle size distribution of the magnetic medium powder, uses a polymer film as a supporting body, uniformly disperses the magnetic medium powder in the glue solution by modification, uniformly coats the glue solution on both sides of the surface, and finally combines the conductive layer to obtain a composite circuit board material integrating electromagnetic shielding, magnetic conduction and electric conduction. The magnetic medium layer serves as an excellent magnetic medium, can constrain the magnetic lines of force passing through the coil to make the magnetic lines of force more concentrated, and can synergize with the electromagnetic shielding layer to enhance the inhibition effect on electromagnetic interference. The conductive layer uses copper as the conductive medium, can be used as the conductive material of the flexible circuit board, and can be used to process into an inductive coil winding, which can not only save cost but also reduce the volume of the wireless charging module. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 FIG. 1 is a structural schematic diagram of the composite circuit board material of the application;

[0035] In the figure, 1 is an electromagnetic shielding layer, 2 is a magnetic medium layer, 21 is a magnetic medium, 22 is a supporting body, 3 is a conductive layer, and 4 is an insulating protective layer. DETAILED DESCRIPTION

[0036] The application will be further described in connection with the following specific examples. It should be understood that the examples are intended to illustrate the application and not to limit the scope of the application. Furthermore, it should be understood that various modifications can be made by those skilled in the art upon reading the teachings of the present application, and such equivalent forms are intended to fall within the scope of the appended claims.

[0037] Example 1

[0038] S1: Preparation of magnetic medium powder

[0039] ①Using iron nitrate and zinc sulfate as raw materials, and urea as a precipitant, a colloidal zinc ferrite precursor was obtained by hydrolysis precipitation method; ②The obtained colloidal precursor was annealed in a muffle furnace, air atmosphere, temperature 450℃, time 3.5h, to obtain porous zinc ferrite, and finally ground to obtain zinc ferrite powder;

[0040] ③The zinc ferrite powder obtained above was added to an ethanol aqueous solution, the mass ratio of ethanol to water was 0.8, the amount of zinc ferrite was 35g / L, and ultrasonic stirring was used to make it fully dispersed, and 0.1g / L of sodium dodecyl sulfate was added as a surface modifier; continuous stirring for 30min;

[0041] ④The surface modified zinc ferrite powder was washed with water and filtered to obtain the powder D 50 =0.36μm, D 90 =0.68μm.

[0042] S2: Preparation of magnetic medium glue

[0043] First, carboxymethyl cellulose was added to pure water, the mass of carboxymethyl cellulose accounted for 2% of the total mass of the glue, and stirring was continued at a speed of 600rpm for 15min; then the zinc ferrite powder obtained in step S1 was added, stirring was continued at a speed of 300rpm for 30min; finally, 8% of the total mass of the glue was added to the butadiene rubber emulsion, and stirring was continued at a speed of 1500rpm for 15min; the viscosity of the finally obtained magnetic medium glue was 2500mPa·s, the solid content was 50%, and the vacuum screening was ≤200mesh.

[0044] S3: Preparation of magnetic medium layer

[0045] ①PI film with a thickness of 12.5μm was selected as a supporting layer, and oxygen was used as a medium for plasma treatment; ②The magnetic medium glue obtained in step S2 was uniformly sprayed on both sides of the supporting body, the single-sided density was 40mg / cm 2 ; the sprayed glue was baked, the baking temperature was 90℃, and the baking time was 30min;

[0046] III. The PI protective film is hot-pressed on the outer surface of the glue liquid on both sides, the pressure of the pressing is 300 psi, and the temperature of the pressing is 150°C; the total thickness of the final glue liquid layer and the supporting layer is 45 μm;

[0047] IV. A layer of metal copper is sputtered on the outer surface of the protective film on both sides to obtain a metallized protective film, wherein the thickness of the copper is 20 nm. S4: Electroplating to obtain an electromagnetic shielding layer and a conductive layer

[0048] I. A metal copper layer is electroplated on the outer surface of the metallized protective film on one side of the supporting body as a conductive layer, the electroplating process parameters are: the direct current density is 40 A / dm 2 , the content of copper ions in the electrolyte is 80 g / L, the acid concentration is 100 g / L, and the thickness of the copper layer obtained as a conductive layer is 75 μm;

[0049] II. The outer surface of the metallized protective film on the other side of the supporting body is electroplated with single metal copper to obtain an electromagnetic shielding layer with a copper thickness of 6 μm.

[0050] S5: A PI insulating protective film is adhered to the outer surface of the conductive layer, the adhesive is an epoxy-based adhesive, and curing treatment is performed to obtain an insulating protective layer.

[0051] Example 2

[0052] S1: Preparation of magnetic medium powder

[0053] I. Using ferric nitrate, zinc sulfate and nickel sulfate as raw materials, and urea as a precipitating agent, a hydrolysis precipitation method is used to obtain a nickel zinc ferrite precursor;

[0054] II. The obtained precursor is annealed in a muffle furnace, the air atmosphere is 600°C, the time is 4h, and finally the nickel zinc ferrite powder is ground;

[0055] III. The obtained nickel zinc ferrite powder is added to an ethylene glycol aqueous solution, the mass ratio of ethylene glycol to water is 0.6, the amount of nickel zinc ferrite is 50 g / L, and 0.5 g / L of sodium polyacrylate is added as a surface modifier; continuous stirring for 60 min;

[0056] IV. The surface modified nickel zinc ferrite powder is washed with water and filtered to obtain a powder D 50 = 0.41 μm, D 90 = 0.78 μm.

[0057] S2: Preparation of magnetic medium glue liquid

[0058] Firstly, sodium tripolyphosphate is added into pure water, the mass of sodium tripolyphosphate accounts for 5% of the whole mass of the glue solution, and stirring is continuously carried out at a speed of 500 rpm for 30 min; then the nickel-zinc ferrite powder obtained in step S1 is added, and stirring is continuously carried out at a speed of 700 rpm for 50 min; finally, 10% of the whole mass of the glue solution is added as polymethyl methacrylate emulsion, and stirring is continuously carried out at a speed of 1000 rpm for 20 min; the viscosity of the final magnetic medium glue solution is 3000 mPa·s, the solid content is 60%, and vacuum screening is less than 200 meshes.

[0059] S3: Preparation of magnetic medium layer

[0060] ①A PET film with a thickness of 12 μm is selected as a supporting layer, and argon is used as a medium to carry out plasma treatment; ②The magnetic medium glue solution obtained in step S2 is uniformly sprayed on both sides of the supporting body, and the single-sided density is 50 mg / cm 2 ; the sprayed glue solution is baked, the baking temperature is 100 ℃, and the baking time is 40 min;

[0061] ③PI protective film is hot-pressed on the outer surface of the glue solution on both sides, the pressure of the pressure bonding is 350 psi, and the temperature of the pressure bonding is 200 ℃; the total thickness of the final glue solution layer and the supporting layer is 50 μm;

[0062] ④A layer of metal copper is sputtered on the outer surface of the protective film on both sides to obtain a metallized protective film, wherein the thickness of copper is 40 nm.

[0063] ①A metal copper layer is electroplated on the outer surface of the metallized protective film on one side of the above supporting body as a conductive layer, and the electroplating process parameters are: direct current density is 60 A / dm 2 , the content of copper ions in the electrolyte is 90 g / L, the acid concentration is 130 g / L, and a copper layer with a thickness of 105 μm is obtained as a conductive layer;

[0064] ②The outer surface of the metallized protective film on the other side of the above supporting body is electroplated with single metal copper to obtain an electromagnetic shielding layer with a thickness of 12 μm;

[0065] S5: A layer of PET insulating protective film is adhered to the outer surface of the conductive layer, the adhesive is polyester adhesive, and curing treatment is carried out to obtain an insulating protective layer.

[0066] Comparative Example 1

[0067] The difference between this example and Example 1 is that there is no electromagnetic shielding layer in this example.

[0068] Comparative Example 2

[0069] The difference between this example and Example 1 is that the thickness of the magnetic medium layer is 20 μm.

[0070] Comparative Example 3

[0071] Different from Example 1, in this example, the thickness of the conductive layer is 30 pm.

[0072] Comparative Example 4

[0073] Different from Example 1, in this example, the step S1, the surface modification of the magnetic medium powder is not performed.

[0074] Comparative Example 5

[0075] Different from Example 1, in this example, the step S1, the D 50 = 0.28 pm, D 90 = 0.57 pm of the final magnetic medium powder is not controlled.

[0076] Comparative Example 6

[0077] Different from Example 1, in this example, the step S3, the magnetic medium glue solution is uniformly sprayed on both sides of the support body, and the single-sided density is 20 mg / cm 2 .

[0078] Comparative Example 7

[0079] Different from Example 1, in this example, the step S3, the support body is not subjected to surface activation treatment.

[0080] In order to more clearly highlight the beneficial effects of the present application, the following detailed description of the examples and comparative examples.

[0081] Comparative Example 1 and Example 1 are compared: the composite circuit board material in Comparative Example 1 has no electromagnetic shielding layer, and if it is processed into a wireless charging module assembly, it cannot completely eliminate electromagnetic interference.

[0082] Comparative Example 2 and Example 1 are compared: the thickness of the magnetic medium layer in Comparative Example 2 is too small, which cannot provide sufficient magnetic force for the induction coil, and thus cannot provide stronger induced current.

[0083] Comparative Example 3 and Example 1 are compared: the thickness of the conductive layer is too small, which cannot bear larger current, resulting in circuit burning.

[0084] Comparative Example 4 and Example 1 are compared: the magnetic medium powder cannot be uniformly dispersed in the glue solution, resulting in uneven magnetic force received by the induction coil, affecting the stability of the circuit.

[0085] Comparative Example 5 and Example 1 are compared: the particle size of the magnetic medium powder is too small, resulting in smaller magnetic domains, which cannot provide sufficient magnetic force, and the magnetic force lines are not concentrated, which will cause the induction coil circuit to leak magnetic.

[0086] Comparative Example 6 is compared with Example 1: the face density of the coating is too small to provide sufficient magnetic force.

[0087] Comparative Example 7 is compared with Example 1: the surface of the support is not activated, resulting in insufficient adhesion of the glue to the support, which can eventually result in poor overflow.

Claims

1. A method for preparing a composite circuit board material, comprising the following steps: (1) preparing a magnetic medium powder; then surface-modifying the magnetic medium powder, using an organic alcohol solution as a solvent and a surfactant as a modifier; washing and multi-stage filtering the surface-modified magnetic medium powder; (2) adding the dispersant into the solvent and mixing and stirring, then adding the magnetic medium powder obtained in step (1) and mixing and stirring uniformly, and finally adding the binder to obtain a magnetic medium glue solution; wherein, D 50 satisfies 0.3 μm < D 50 < 0.5 μm, D 90 satisfies 0.6 μm < D 90 < 1.0 μm; (3) uniformly spray the magnetic medium glue solution obtained in step (2) on both sides of the support body, the single side density is 40 mg / cm 2 or 50 mg / cm 2 , then baking; then hot-press a protective film on the outer surface of the magnetic medium glue solution on both sides, finally sputter copper on the outer surface of the protective film to obtain a magnetic medium layer; wherein the thickness of the magnetic medium layer is 30-50 μm; the support body is a polymer film treated by plasma surface activation. (4) electroplating a copper layer as a conductive layer on one side of the magnetic medium layer obtained in step (3), and electroplating an electromagnetic shielding material on the other side; adhering an insulating protective film to the outer surface of the conductive layer and performing a curing treatment to obtain an insulating protective layer, thereby obtaining the composite circuit board material; wherein the thickness of the conductive layer is 35-105 μm.

2. The method of claim 1, wherein: The organic alcohol in step (1) includes one or more of ethanol, ethylene glycol, diethylene glycol, glycerol, pentaerythritol, neopentyl glycol, and 1,4-butanediol; the surfactant includes one or more of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium pyrophosphate, and sodium polyacrylate.

3. The method of claim 1, wherein: The solvent in step (2) is pure water; the dispersant includes one or more of carboxymethyl cellulose, gum, and sodium tripolyphosphate; and the binder includes one or more of butadiene-styrene rubber emulsion, polyvinyl alcohol, polymethyl methacrylate emulsion, thermoplastic polypropylene emulsion, and polyvinyl acetate emulsion.

4. The method of claim 1, wherein: The protective film in step (3) is further provided with a glue layer between the protective film and the magnetic medium glue solution.

5. The composite wiring board material produced according to the production method of claim 1, characterized by: The composite circuit board material comprises an electromagnetic shielding layer, a magnetic medium layer, a conductive layer, and an insulating protective layer; the magnetic medium layer is prepared from a magnetic medium glue solution and a supporting body.

6. The composite wiring board material according to claim 5, characterized by: The material used for the electromagnetic shielding layer is a metal material, a metal composite material, or a metallized polymer material; the thickness of the electromagnetic shielding layer is 5-50 μm, and the area is greater than that of the magnetic medium layer and the conductive layer.

7. The composite wiring board material of claim 5, wherein: The magnetic conductive material used for the magnetic medium layer includes one or more of zinc ferrite, nickel ferrite, manganese zinc ferrite, nickel zinc ferrite, copper zinc ferrite, and metal magnetic powder material; the magnetic permeability of the magnetic medium layer is 100-2000 H / m.

8. The composite wiring board material of claim 5, wherein: The material of the conductive layer is copper, and the conductive layer is fixed to the side of the magnetic medium layer that is away from the electromagnetic shielding layer.

9. The composite wiring board material of claim 5, wherein: The material of the insulating protective layer is PET, PI, or PP.

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