KR100835558B1 - Method of coating and granulating a powder by spray dryer process, and method of manufacturing one-body smd inductor thereby - Google Patents

Abstract

A method for coating and granulating powder by a spray dryer process and a method for manufacturing an one-body SMD(Surface Mounted Device) inductor are provided to improve a collection rate of powder for forming through granulation into a predetermined particle size during a process. A method for coating powder by a spray dryer process includes the steps of: manufacturing a coating liquid by dissolving or dispersing an inorganic based coating agent including sodium silicate, potassium silicate, SiO2 and any one coating agent selected from a group consisting of an organic based coating agent including epoxy based resin, polyester based resin, polyetherimide based resin, polyimide based resin, and phenol based resin in one of an organic solvent and an inorganic solvent; and forming a film of the coating agent on the surface of the powder to be coated and granulating the powder into a proper size by simultaneously spraying and drying a slurry obtained by mixing the coating agent with the powder to be coated in a chamber of spray drying equipment through a disc rotating at high speed.

Description

Coating and granulation process of powder using spray drying process and manufacturing method of integrated SMD inductor using the same {Method of coating and granulating a powder by spray dryer process, and method of manufacturing one-body SMD inductor hence}

The present invention relates to a method of coating and assembling a powder using a spray dryer process and a method of manufacturing an integrated SMD (Surface Mounted Device) inductor using the same, and more specifically, using a spray drying process. By uniformly applying the coating to the powder to make it granular, increasing the yield of the powder during the granulation process, and achieving uniformity between molded products in the manufacture of SMD inductors and simplifying the process. It relates to a manufacturing method of.

In addition, the present invention improves the flow rate of the coating powder by granulating the powder during the coating process of the powder, thereby excellent in formability, and by reducing the density difference between the molded products, improving the productivity of the product and variation in characteristics. The present invention relates to a method for manufacturing an integrated SMD inductor which can simultaneously reduce the voltage.

In the case of applying the existing coating method, it is possible to reduce the characteristics of the product due to the difficulty in controlling the coarse coating of the coating layer and the powder, and the dispersion between the products. An additional process for reducing the yield of the coating powder and the pulverization of the granulated powder may occur, and it is a problem to be solved by the present invention.

Recently, due to the high performance of various electronic devices and components, the demand for inductors having soft magnetic characteristics of medium, small, or high performance is increasing. In particular, as the demand for notebooks, LCD TVs / VGAs, and computer / servers increases, the demand for smaller packages increases. This situation requires battery life. In order to satisfy this demand, the demand for inductors driven at high current is increasing. In order to meet the demand of the market, development and application of inductors having high current characteristics and magnetic characteristics are widely progressed. In particular, a separate SMD inductor that inserts and assembles a coil after molding or an integrated SMD inductor that inserts and forms a coil As such, the use of SMD inductors including a coil inside is prominent.

In the case of the integrated SMD inductor, it is mainly used to rectify AC current or remove noise in DC output circuit, and the coating agent is coated on carbonyl iron powder having an average particle size of 10 μm or less. Binder), etc., by coating, and granulated, and then mixed with a lubricant to grind and classify the coated powder into a size that is easy to mold, insert a coil into the inside, and then form a curing process. It is common to carry out the process to manufacture.

However, the conventional powder coating method (mixing method) is difficult to effectively uniformly uniformly insulate or finely granulate the fine powder of 10 μm or less, and thus deteriorate the characteristics of the finally fabricated integrated SMD inductor. Or, it is difficult to implement the optimal characteristics, in particular, due to excessive granulation occurs during the coating process, such as the need for the regrinding process or recoating process is reduced productivity.

In the present invention, in order to solve the conventional problems, the coating film is coated on the surface of the powder during the process of spraying by dropping a slurry (Slurry) mixed with the powder and the coating liquid on a disk rotating at high speed using a spray drying process Invented is a coating and granulation process of powder, which is formed and granulated at the same time, and a method of manufacturing an integrated SMD inductor using the same.

Therefore, in the case of applying the spray-drying coating process as in the present invention, the flow rate of the coating powder is improved through the granulation to an appropriate particle diameter which is easy to uniform coating and molding, and the amount of powder injected during molding It can be controlled well, producing high quality products uniformly and improving productivity.

This process advantage can increase the yield of the coated and granulated powder, it is possible to achieve excellent properties, uniform product characteristics and high productivity in the final product.

An object of the present invention is to provide a method for manufacturing an integrated SMD inductor by simultaneously applying a spray drying process to the coating surface more uniformly on the surface of the powder and assembling to an appropriate size. In addition, it improves the recovery rate of powder after coating and granulation process, simplifies the process, and improves the formability through proper granulation during the process, thereby providing a method to uniformly manufacture high-performance integrated SMD inductors with high productivity. It is.

In order to achieve the above technical problem, in the present invention, (i) an inorganic coating agent including sodium silicate, potassium silicate, and silicon dioxide (SiO 2), epoxy-based resin, and polyester-based The coating agent selected from the group consisting of an organic coating agent including a resin, a polyetherimide resin, a polyimide resin, and a phenol resin is one selected from an organic solvent and an inorganic solvent. Dissolved or dispersed in a solvent to prepare a coating solution,

(Ii) mixing the coating solution with the powder to be coated to form a slurry, and drying the sprayed liquid using a disc rotating at a high speed in a chamber of the spray drying equipment to dry the sprayed surface on the surface of the powder to be coated. It provides a coating and granulation method of the powder using a spray drying process, characterized in that the coating to form a coating and at the same time to granulate the powder to an appropriate size.

In addition, the present invention is an inorganic coating agent containing (i) sodium silicate, potassium silicate (Potassium Silicate) and silicon dioxide (SiO2) and epoxy resins, polyester resins, A coating agent selected from the group consisting of an organic coating agent including a polyetherimide resin, a polyimide resin, and a phenol resin is added to one solvent selected from an organic solvent and an inorganic solvent. Dissolve or disperse to prepare a coating solution,

(Ii) mixing the coating solution with the powder to be coated to form a slurry, and drying the sprayed liquid using a disc rotating at a high speed in a chamber of the spray drying equipment to dry the sprayed surface on the surface of the powder to be coated. At the same time to form a coating film of the coating agent to granulate the powder to the appropriate size,

(Iii) forming the coated and granulated powder at a pressure of 2-18 ton / cm 2 with the coil inserted therein;

(Iii) It provides a method of manufacturing an integrated SMD inductor, characterized in that the molding is heat-treated at 100-800 ° C.

Hereinafter, the present invention will be described in detail.

The present invention is an inorganic coating agent including sodium silicate, potassium silicate and silicon dioxide (SiO2) and epoxy resins, polyester resins, polyetherimide resins, polyimide One coating agent selected from the group consisting of an organic coating agent including a resin and a phenol resin is dissolved or dispersed in an organic solvent or an inorganic solvent to prepare a coating solution, and then the coating solution is mixed with a powder. After the slurry is formed, it is sprayed and dried using a disk (Disc) rotating at a high speed in the chamber of the spray drying equipment to form a coating film on the surface of the powder to be coated, and at the same time the powder is appropriately sized. Assemble with

The coating agent is cured during the heat treatment after molding the integrated SMD inductor to give strength to the integrated SMD inductor, and has a certain bonding strength even at room temperature to prevent cracking while maintaining the strength of the inductor according to pressure even when molded at room temperature. If it can, it is not particularly limited.

The coating agent used in the present invention should be excellent in electrical insulation, and examples thereof include inorganic coating agents including sodium silicate, potassium silicate and silicon dioxide (SiO 2) or epoxy resins, polyester resins, One type selected from organic coating agents including polyetherimide resin, polyimide resin, and phenol resin is used.

The preferred amount of the coating agent is 0.2-10.0% by weight, more preferably 0.5-5.0% by weight, based on the total weight of the powder to be coated. If the amount of the coating agent is less than 0.2% by weight, the bonding strength is weak, and after forming the magnetic powder, the strength may be decreased or cracks may be generated, and the core loss or frequency characteristics may decrease after heat treatment, whereas 10.0 When the weight percentage is exceeded, the amount of the coating agent becomes relatively large, and the bonding strength between the magnetic powder particles becomes strong. However, when the amount of the coating agent in the molding is large, the soft magnetic properties decrease. In addition, the coating solution may further contain 0.1 to 5% by weight relative to the total weight of the powder to be coated with an insulating material selected from kaolin, talc or magnesium hydroxide.

The organic solvent or the inorganic solvent is not particularly limited as long as it can dissolve the coating agent or disperse the insulating material, and can be easily volatilized at the spray drying process temperature. More preferably, water is used for the silicate coating agent, acetone is used for the epoxy and polyester coating agents, methylene chloride is used for the polyetherimide coating agent, and alcohol is used for the coating agent which is a phenol resin. At this time, the preferred amount of the solvent is used 0.1-2L of water or organic solvent per kg of the coating agent. The powder to be coated includes a known magnetic material, and is a representative example, including carbonyl iron having a particle size distribution of about 1-10 μm, iron having a particle size distribution of 150 μm or less, or silicon having a diameter of 150 μm or less. One selected from iron (Fe-Si) and various magnetic powders is used.

Subsequently, the coating and granulation process is carried out while spraying and drying the mixture of the powder on the slurry and the coating liquid through a disk (Disc) rotating at a high speed in the chamber of the spray drying equipment. At this time, the feed rate of the slurry is 10-1000 ml / min, the disk rotation speed is controlled to about 2,000-30,000 RPM to prepare a powder coated and granulated. At this time, the slurry (Slurry) is sprayed through a rotating disk (Disc) in the chamber of the spray drying equipment that is maintained at an appropriate temperature while the solvent of the slurry is volatilized and the coating agent forms a coating film on the surface of the powder particles and the appropriate size The process of assembling is carried out simultaneously. At this time, in order to smooth the volatilization of the solvent, the temperature inside the chamber is different depending on the solvent used, but it is preferable to maintain at 30-300 ℃, if less than 30 ℃ even using an organic solvent is not easy to volatilize, 300 When the temperature is exceeded, the characteristics are degraded due to the oxidation of the powder, or the molding is not easy due to the curing of the coating agent. Coating and granulation of the powder using the spray drying process improves the physical and chemical properties such as electrical insulation, stability and flowability of the powder by a uniform coating film formed on the surface of the powder particles.

The coating and granulation method of the present invention can freely control the granulation degree of the powder, compared to the existing mixing process, and can be granulated to a desired size, resulting in excessive granulation generated in the existing process. And no post-processing such as pulverization is required, and since a uniform coating film can be obtained on the surface of the powder, the characteristics of the product are excellent, and the process can be completed in a short time and economically.

In addition, the present invention provides a method for manufacturing an integrated SMD inductor using the powder coated by the spray drying process described above. The step of uniformly coating the inorganic or organic coating agent on the surface of the powder can be carried out as described above. Specifically, the powder coated and granulated with the above is molded at a pressure of 2-18 ton / cm 2 at room temperature. The molding process was molded at a rate of 5-20 pieces / minute, and the faster the molding speed is economical if the same characteristics can be achieved.

After the molding process, heat treatment is carried out at a temperature of 100-800 ℃. Such a heat treatment process can remove the internal stress caused during powder manufacturing or molding and harden the coating to increase the strength or control the characteristics of the molded integral SMD inductor.

The heat treatment process is preferably carried out in a non-oxidizing atmosphere, the non-oxidizing atmosphere is reduced by using argon (Ar) gas or nitrogen (N ₂ ) gas, or reducing gas such as hydrogen (H ₂ ) gas To maintain a gas atmosphere. The heat treatment temperature is preferably carried out at 100-800 ℃, if less than 100 ℃, there is a problem that the strength of the coating agent of the heat-treated inductor is not sufficiently cured, the strength is weakened, if it exceeds 800 ℃, there is no further improvement of characteristics, It is not preferable because the insulation property of the coating agent is lowered. Moreover, preferable heat processing time is 10-180 minutes, and when heat processing time is less than 10 minutes, when stress removal is not enough and it exceeds 180 minutes, productivity will fall and it is unpreferable.

Hereinafter, embodiments of the present invention will be described in detail. The following examples are merely illustrative of the present invention, but the scope of the present invention is not limited to the following examples.

Example  One

A coating solution was prepared by dissolving 3.0% by weight of epoxy as a coating agent in acetone at a ratio of 1:10 (resin: solvent), and coating carbonyl iron powder having an average particle diameter of 10 μm or less. It is dispersed in to prepare a slurry (Slurry) phase. The slurry thus prepared was sprayed into the spray drying chamber by using a disk (Disc) rotating at a high speed in the chamber of the spray drying equipment, and the powder was uniformly coated on the surface of the powder particles, and granulated powder was prepared at the same time.

After classifying the coating powder prepared above 100 mesh (Mesh) or less, and then add a zinc stearate (lubricant zinc stearate) by adding 0.2% by weight to the weight of the coating powder, the mixed powder prepared is a coil inside It was formed into an inductor of 10.0mm × 10.0mm × 4.0mm (width × length × thickness) at a pressure of 5 ton / ㎠ at room temperature, and then heat-treated at 150 ° C. for 60 minutes to manufacture an integrated SMD inductor. It was.

Example  2

An integrated SMD inductor was manufactured in the same manner as in Example 1, except that the magnetic powder used was changed to iron powder of 100 mesh or less.

Example  3

In the same manner as in Example 1, except that the magnetic powder used was changed to silicon iron (Fe-Si) powder of 100 mesh or less, and a pressure of 10 ton / cm 2 was applied during molding, the integrated SMD inductor was used. Prepared.

Example  4

The coating agent was prepared in the same manner as in Example 1 except that water glass (Sodium silicate) using water as a solvent and the heat treatment temperature was set to 700 ℃.

Example  5

An integrated SMD inductor was manufactured in the same manner as in Example 1, except that the coating agent was changed to polyester.

Example  6

The coating agent was prepared in the same manner as in Example 1, except that polyetherimide using a solvent as methylene chloride was used, and the heat treatment temperature was 300 ° C.

Comparative Example  One

A coating solution was prepared by dissolving 3.5% by weight of epoxy as a coating agent in acetone in a ratio of 1:10 (resin: solvent). Carbonyl iron powder having an average particle diameter of 10 μm or less and the coating solution prepared above are charged to a mixer, mixed, dried, and classified to 150 μm or less. The mixed powder prepared by adding 0.2% by weight of zinc stearate, a lubricant, to the sorted powder, and mixing the powder is 10.0mm × 10.0mm at a pressure of 5 ton / ㎠ at room temperature so that the coil is included inside. A molded SMD inductor was manufactured by forming an inductor having a size of 3.5 mm (width × length × thickness) and heat-treating at 150 ° C. for 60 minutes to cure the coating.

By analyzing the particle size of the coating powder prepared in Examples 1-6 and Comparative Example 1 was measured the flow rate (flow rate) of the coating powder and the recovery of the powder below 150㎛ that can be molded. The measurement results are shown in Table 1 below.

Measurement result of flowability and recovery rate of coating powder division Flow Rate of Coating Powder [sec / 50g] Coating powder recovery rate of less than 150㎛ [%] Example 1 31 95 Example 2 39 93 Example 3 31 94 Example 4 36 92 Example 5 32 93 Example 6 34 94 Comparative Example 1 38 65

In Table 1, the coating powder recovery rate of 150 μm (100 mesh) or less is measured without any additional process after coating.

The characteristics of the integrated SMD inductors manufactured by Example 1-6 and Comparative Example 1 were evaluated. The measurement results are shown in Table 2 below.

Characteristic measurement result of manufactured integral SMD inductor division Inductance [μH, 100 ㎑, 0.25 V] Saturation Current [A] Example 1 1.0 39 Example 2 0.7 35 Example 3 1.4 35 Example 4 0.9 38 Example 5 1.0 37 Example 6 1.1 38 Comparative Example 1 0.9 40

As described above, the present invention by using a spray drying process, by providing a powder coating method that can obtain a uniform coating layer on the surface of the magnetic powder,

First, it can improve the characteristics of the SMD inductor, which is the final product by achieving a uniform assembly compared to the existing mixing method,

Second, through the granulation to a certain particle size during the process, it is possible to improve the flowability of the coating powder, improve the formability, and increase the recovery rate of the moldable powder by more than 20%,

Third, by simplifying the process to shorten the coating process time of the powder particles, and eliminating the post-process such as pulverization, it is possible to manufacture an integrated SMD inductor of excellent economic properties.

Although the present invention has been described in detail only with respect to the embodiments described, it will be apparent to those skilled in the art that various modifications and changes are possible within the scope of the technical idea of the present invention, and such modifications and modifications belong to the appended claims. It is natural.

Claims (6)

(Iii) Sodium Silicate, Potassium Silicate, and Inorganic Coatings including Silicon Dioxide (SiO2), Epoxy resins, Polyester resins, Polyetherimide The coating solution is prepared by dissolving or dispersing one coating agent selected from the group consisting of an organic coating agent including a resin, a polyimide resin, and a phenolic resin in one solvent selected from an organic solvent and an inorganic solvent. Manufacturing, (Ii) mixing the coating solution with the powder to be coated to form a slurry, and drying the sprayed liquid using a disc rotating at a high speed in a chamber of the spray drying equipment to dry the sprayed surface on the surface of the powder to be coated. The coating method of the powder using the spray drying process, characterized in that to form a coating film of the coating agent and at the same time to granulate the powder to an appropriate size. The method of claim 1, wherein the coating liquid is prepared by dissolving or dispersing 0.2-10.0% by weight of the coating agent in a solvent relative to the total weight of the powder to be coated. The powder coating method using a spray drying process according to claim 1, wherein the powder to be coated is magnetic powder. (Iii) inorganic coatings including sodium silicate, potassium silicate and silicon dioxide (SiO2), epoxy resins, polyester resins, polyetherimide The coating solution is prepared by dissolving or dispersing one coating agent selected from the group consisting of an organic coating agent including a resin, a polyimide-based resin, and a phenol-based resin in one solvent selected from an organic solvent and an inorganic solvent. Manufacturing, (Ii) mixing the coating solution with the powder to be coated to form a slurry, and drying the sprayed liquid using a disc rotating at a high speed in a chamber of the spray drying equipment to dry the sprayed surface on the surface of the powder to be coated. At the same time to form a coating film of the coating agent to granulate the powder to the appropriate size, (Iii) forming the coated and granulated powder at a pressure of 2-18 ton / cm 2 with the coil inserted therein; (Iii) A method of manufacturing an integrated SMD inductor, wherein the molded product is heat-treated at 100-800 ° C. The method of claim 4, wherein the coating liquid is prepared by dissolving or dispersing 0.2-10.0 wt% of the coating agent in a solvent relative to the total weight of the powder to be coated. The method of manufacturing an integrated SMD inductor according to claim 4, wherein the powder to be coated is magnetic powder.