JP3293223B2 - Film formation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a film.
Techniques for forming a film on various components are widely used industrially. Since the film determines the appearance of the product, serves as a contact point between the product and the environment, and greatly affects the value of the product, the film forming method requires extremely high reliability. In addition, in the film forming technique, it is an important issue to reduce the film forming cost so that the film forming does not occupy a major part of the product cost, in addition to the above-mentioned requirements. The following technologies are the mainstream at present, as examples of resin coatings.

[0002]

[Prior art]

(1) Electrodeposition The component is immersed in a liquid in which charged resin powder is suspended,
When a voltage is applied to the component by an external power supply, the charged resin powder is attracted to the component, and the component is covered with the resin powder. Thereafter, heating is performed to melt or / and crosslink the resin powder to form a strong continuous film on the component.

(2) Electrostatic coating A component to which a voltage is applied is placed in a space where resin powder having a charge is scattered, thereby attracting the resin powder onto the component and forming a resin powder film on the component. Form. This is heated to melt and crosslink to form a strong continuous film on the part.

(3) Spray coating A resin is diluted with a solvent, and a film is formed by spraying the resin. Then, the solvent is evaporated and melt-crosslinked to form a film on the part.

(4) Dip coating In the case of a low-viscosity resin liquid or a high-viscosity resin, the components are immersed in a tank of a liquid whose viscosity has been reduced by diluting with a solvent, and the resin is adhered to the surface and melt-crosslinked. To form a film.

However, the conventional film forming method has the following problems. (1) Electrodeposition work It is necessary to work to attach the parts to the electrodes, and no film is formed on the parts where the electrodes are attached.
After the film is formed, an operation called touch-up is required to apply resin to the portion. Both of these require the introduction of a robot that performs manual or complicated movements, which increases the cost of surface treatment. Further, the used electrodeposition solution must be disposed of as industrial waste.

(2) Electrostatic coating There is the same problem as in (1). Further, since the powder is scattered, there is a risk of dust explosion, and a large-scale device for preventing dust scattering and explosion is required.

(3) Spray coating The operation of the spray gun requires skill. Operation by a robot is possible, but it requires complicated movements. Since the film thickness greatly depends on the operation of the spray gun, it tends to be non-uniform. After spraying one of the parts on one side, it is necessary to turn the part over to spray the other side. In order to be sprayed, the resin must be diluted with a large amount of solvent. After the application, a process for preventing pollution is required in a step of evaporating the solvent.

(4) Immersion coating Since a large number of parts can be painted in a basket or the like and painted at once in a short time, the immersion method is the most efficient and inexpensive without the problems of (1) and (3). Painting method. However, in this method, liquid dripping and liquid pooling are inevitably generated, and conversely, liquid does not drip or an extremely thin portion is easily formed, and the reliability of the method for forming a film is much lower than the above method.

In order to solve the problems of the conventional film forming method as described above, the applicant of the present invention disclosed in Japanese Patent Application No. 3-224772 a part to be processed, at least partially uncured at least at the beginning of the film forming process. , Powder (which may be a resin powder harder than the resin in the process of forming a film), and a size substantially smaller than the part to be processed and substantially larger than the powder A method of forming a film, characterized in that a film is formed on the surface of the component to be processed by applying vibration or stirring to the film forming medium in a container. In this method, an uncured resin (which may be pre-coated on the part) forms a film on the part to be processed, and the powder that has been hit by the film forming medium is incorporated into the film. Causes film formation.

Further, in Japanese Patent Application No. 4-232681, the above-mentioned powder is composed of one kind or two or more kinds of substances, and the whole or a part of the powder is formed by heating after forming a powder film. An application was filed for a method that requires melting. According to this method, the powder in the powder compression layer coated on the surface of the component melts and adheres to each other, so that there is no risk of powder falling off during use of the component. In addition, there is no need to apply an overcoat to prevent powder from falling out of the powder compression layer. Due to these advantages, a coating more suitable for various components such as automobiles and home appliances was obtained.

[0012]

Although the film forming method proposed by the present applicant can solve the problems of the conventional film forming method, it is applied to relatively complicated parts such as rings and small parts. However, when the film grows locally and the frequency of impact of the film-forming medium, such as the inner peripheral surface of the ring, tends to decrease, the film thickness becomes thinner and uniform coating may not be possible. In some cases, the smoothness of a film formed on a similar part was not good. Furthermore, when heating was performed after the formation of the film, the film became soft, and the parts were greatly deformed on the surface in contact with the support, leaving traces on the contact surface, deteriorating the commercial value. An object of the present invention is to solve these problems, thereby expanding the applicable range of the film forming method of the prior application, ensuring uniformity and smoothness of the film thickness, and further preventing deformation during heating. Things.

[0013]

In order to solve the above problems, the present inventors have devised each step of the film forming method as follows. (1) A layer having an adhesive property (hereinafter, referred to as an “adhesive layer”) is attached in advance to a component to be processed (hereinafter, referred to as a “component”) in order to increase the powder adhesion efficiency. (2) Vibrating or agitating the component, the film-forming medium and the powder in (1) in a container to attach the powder to the component. Here, the film-forming medium mediates the adhesion of the powder but does not adhere to the part or adheres slightly to the extent that no film is formed. (3) The part to which the powder is attached is heated to a temperature equal to or higher than the melting point of the powder to melt the powder. However, flat powder that does not melt is included in the powder of (2).

Therefore, the method of the present invention relates to a method for treating a component having an adhesive layer on at least a part of its surface, a powder comprising two or more substances having different melting points, provided that at least one of the high melting point powders has a shape. Flat—the film forming medium having dimensions substantially smaller than the part to be processed and substantially larger than the powder is subjected to vibration or agitation in a container to apply the vibration or agitation to the surface of the part to be processed. A method for forming a film, comprising: forming a film containing a powder; and thereafter heating the film to a temperature equal to or higher than any one of the melting points of the powder, but equal to or lower than any one of the melting points of the flat powder.

Hereinafter, each step will be described in more detail. The role of the adhesive layer is to adhere powder to the surface of the component by the film-forming medium during vibration / stirring and adhere to the component layer, and to exude between the powder particles already adhered to the surface of the powder. It is to glue. That is, the layer must have sufficient adhesion to keep the powder firmly on the part. For example, very high viscosity oils can be used to form the adhesive layer, but low viscosity oils cannot. An uncured resin having high adhesiveness is a desirable adhesive layer. After heating and melting a part of the charged powder in the heating step subsequent to the vibration / stirring step, the adhesive layers do not need to have an adhesive effect even after the heating and melting, since the powders are bonded to each other by melting. However, when a resin that does not cure is used for the adhesive layer, the powders are bonded after the heating and melting step, but the powder bonded layer may not strongly adhere to the component. Therefore, as the adhesive layer, it is optimal to use a curable resin having an adhesive effect both during vibration / stirring and after heating and melting in an uncured state.

As the uncured resin, resins that can be cured with resins such as epoxy and phenol and various monomers can be used. Polyvinyl alcohol (PVA), water glass, and the like can also be used as the adhesive layer. However, PVA, water glass, and the like lose adhesiveness when water evaporates, and therefore must be used in a state that contains sufficient water. The water contained therein evaporates in the heating step after forming the powder layer on the part. Regarding the resin, even those that cannot be cured, as long as they have adhesive properties, various kinds of strong adhesive resins can be used. An adhesive layer made of a resin is formed by adding a thermosetting resin such as an epoxy resin (an appropriate amount of a curing agent is mixed) to an ME.
This is performed by immersing the component in a liquid dissolved in a solvent such as K and drying. At this time, MEK of epoxy resin
The higher the weight ratio of the adhesive layer, the greater the thickness of the adhesive layer formed on the component surface. When using a liquid obtained by diluting an epoxy resin with MEK, a liquid having a concentration of the epoxy resin of 2 to 30% is a standard. As the resin for forming the adhesive layer,
It is most desirable to use a strong adhesive represented by an epoxy resin. In the following description, a case where the adhesive layer is an uncured resin will be described.

The force of the film-forming medium is applied from the powder to the workpiece by vibration or stirring. This method can be of various types, for example, using a blade rotating in the container, rotating the container, shaking, or placing it on a diaphragm. Also, the component to be processed may be mixed with the film-forming medium in the container, or may be hung in the container or in contact with the surface of the medium. As exemplified here, various methods can be used for the method of vibration or stirring, and the present invention is not limited to the specific method of vibration or stirring. The powder to be vibrated or agitated must be harder than the uncured resin of the adhesive layer and maintain a powder form, so that the powder is pushed into the uncured resin film during vibration or agitation.

As the powder, any kind of resin powder, two or more kinds of metals or inorganic substances can be used in combination. The resin powder is an uncured or cured thermosetting resin or thermoplastic resin.

The flat powder that is not melted by heating is preferably flat before being subjected to vibration or stirring.
It may be a powder such as aluminum or silver that has been flattened and deformed by impact with a film-forming medium during vibration or stirring. The flat shape has a substantially flat surface,
Such a surface is a disk, a flat plate, a curved plate, or the like, which is a main constituent surface of the powder. Preferably, the relationship between the distance H between the opposed flat surfaces and the average diameter D of the flat surfaces (diameter when converted into a circle of the same area) is H / D <1/2, more preferably H / D <1/2. D <１ ／, and most preferably H / D <１ ／.

As the powder that can be melted by heating (hereinafter referred to as "low-melting powder"), resin powder such as epoxy, acryl, polyester and the like, low-melting metal or inorganic powder can be used, but resin powder is preferable. Since these powders are deformed by pressure or impact, the initial shape is not particularly limited and may be flat.

As in the case of resin powders used in various coatings, it is possible to include an inorganic pigment such as TiO 2 or red iron oxide which has a high melting point and does not melt by heating, such as resin powder. Such pigments do not usually have a flat shape and thus have no effect on the uniform growth of the film, but exhibit aesthetic and anticorrosion functions in the film after heating.

Therefore, in the present invention, as a combination of powders, a powder of any shape that can be melted may be combined with a flat powder that does not melt, and a powder of any shape that does not melt may be combined with this combination. Good. The heating of the present invention is performed by holding the powder at a temperature equal to or higher than the melting point of the resin or the like for several seconds to several hours. However, the melting point here means
The melting point is not always clearly defined physically. Here, the melting point means a temperature at which the used powders start to unite with each other. As is well known, amorphous materials do not have a well-defined melting point and gradually soften from around a temperature called the glass transition point. This temperature is also included in the melting point of the present invention. When a thermosetting resin such as an epoxy resin is used as a melting substance, it is necessary to use an uncured resin. These uncured resins are low molecular and have low melting points or glass transition points. When these uncured resin powders are heated above the melting point or glass transition point, the powders once melt and coalesce. At this time, the polymerization of the molecules occurs simultaneously due to the catalytic action of the curing agent and the like, and is cured. Once cured, the thermosetting resin does not melt at the above melting point or the like.

[0023] The coating may be formed directly on the part,
Further, other coatings, for example, a prior application of the present applicant (Japanese Patent Application No.
No. 4782, Japanese Patent Application No. 4-232681) or the coatings of the prior arts (1) to (4) may be already formed. The method of the prior application may be performed after the method of the present invention is performed. These methods may be repeated in any order, in which case an operation of bonding the uncured resin between each operation, for example, spray coating may be performed. Further, a multilayer film in which the ratio of the flat powder decreases, for example, from the inner layer to the outer layer may be formed by the method of the present invention. The flat powder may be a mixture of different kinds of powder such as mica and BN. When the proportion of flat powder is increased for the purpose of increasing the hardness of the film or giving it a gloss, the top coat such as epoxy resin melted with MEK is applied in the usual way to prevent powder dropping and surface Can be repaired.

Next, embodiments of the method of the present invention and preferable conditions will be described. The feeding order of the powder, the film-forming medium, and the components (these are collectively referred to as “film-forming mixture”) may be performed simultaneously or sequentially. The powder and the film-forming medium may be charged, and these may be subjected to vibration or agitation to spread the powder evenly throughout the entire body, and then the articles may be charged.
In this case, the powder once adheres to the film-forming medium depending on the type and particle size, and then adheres to the article to be processed.

Following the formation of the adhesive resin film, the powder is captured and fixed to the resin layer by the adhesive force of the resin layer. When the resin layer cures on the component surface, it captures and cures the powder. The film-forming medium undergoing vibration or agitation imparts a striking force to the similarly vibrated or agitated powder, creating a powder compaction layer.

Although the film-forming medium generates a striking force to mediate the formation of the film, the medium itself does not substantially become a component of the film. A film-forming medium larger than the part cannot generate a uniform impact force on the former surface, and if smaller than the powder, the film-forming medium is trapped in the film. However, a medium larger than the component may be included as long as the volume ratio is in the range of 70% or less. Also, when the impact force is concentrated to some extent, the powder press-in proceeds well, and for example, when a spherical medium is used, the diameter is 0.3 mm.
As described above, more desirably, 0.5 mm or more is desirable, and the same applies to other shapes. Also, smaller than a part means that when each medium is replaced by a sphere of the same volume, its diameter is smaller than the largest one of the parts. In addition, a desired impact force can be produced for the powder if the requirements are satisfied in the average size. That is, even if some of the particles serving as the film forming medium are finer than the powder, a desired impact force can be produced if the former is larger than the latter in average size. However, media finer than these powders may be incorporated into the film,
It is desirable that it is not included as much as possible.

The material of the film-forming medium must satisfy the following requirements. Observation of the film-forming medium after film formation due to plastic deformation does not cause a large change in shape that can be recognized by the naked eye, and elastic deformation does not become extremely large during the film formation process. Therefore, soft rubber does not satisfy this requirement. No cracks, chips, rapid wear, etc. (some wear may be caused by long-term use).

If a film-forming medium of a material that does not satisfy these requirements undergoes plastic deformation or extremely large elastic deformation such as soft rubber due to collision with the material to be processed, the impact on the latter will be insufficient. And the desired film formation does not occur. Further, if cracks, chips, or rapid wear occur, the useful life of the medium is shortened, which is uneconomical.

The powder must be smaller than the film-forming medium in order to be incorporated into the film. First, the non-flat powder and the powder melted by the flat powder will be described. The particle size of the powder depends on the size of the part, the thickness of the coating and the material of the powder. In the case of hard and hardly deformable powders such as ceramic powders, the particle size is desirably small, and in the case of metal powders with high ductility, etc., the particle size may be larger, but generally in the range of 0.01 to 500 μm. Preferably from 0.05 to 200 μm, more preferably from 0.1 to 70
It is in the range of μm. Generally, the smaller the particle size of the powder, the more easily the powder is captured by the resin. In addition, small particles are
The powder particles dispersed on the resin film are easily pushed into the surface by impact and are easily pressed or bonded to each other or the material to be processed due to plastic deformation. Therefore, the smaller the particle size of the powder, the smaller the impact force and the smaller the surface roughness of the film. However, if the particle size is too small, the powder is likely to aggregate, making it difficult to form a uniform film.

Next, the flat powder that does not melt is preferably milled powder of aluminum, copper, silver, tin, zinc or an alloy thereof. Since these have ductility, a flat surface is greatly developed by milling, and has a remarkable property of promoting uniform growth of a film described later. In addition, substances that become flattened by cleavage such as mica and BN can also be preferably used. The diameter D of the flat powder is preferably 300 μm or less. Exceeding this dimension decreases the uniformity of the film thickness. More preferred dimensions are 150 μm or less, most preferably 70 μm.
μm or less. The smaller the diameter D, the higher the uniformity of the film thickness. However, if the diameter D is too small, the effect of uniforming the film thickness of the flat powder is reduced. Therefore, D of the flat powder is desirably 0.1 μm or more, preferably 1 μm or more.

The film forming medium is made of iron, carbon steel, other alloy steel, copper and copper alloy, aluminum and aluminum alloy, other various metals and alloys, or Al 2 O 3,
Ceramics such as SiO2, TiO2, ZrO2, and SiC, glass, and hard plastics can be used. Hard rubber can also be used as long as a sufficient impact force is applied to film formation. The size and material of these media need to be appropriately selected according to the shape and size of the parts and the material of the powder to be used. In addition, a mixture of media of a plurality of sizes and materials can be used. In some cases, it may be used after surface treatment and surface coating.

A composite medium composed of a plurality of the above-mentioned materials may be used. In addition, in order to alleviate and average the impact force and to suppress the uniformity of the film and the variation in the film thickness, a soft medium such as wood flour, soft rubber, or soft plastic is used in a range of 50% or less of the volume ratio to the medium. May be appropriately mixed. Since these hardly generate a striking force by themselves, they are always used in combination with the film-forming medium. Further, a film of a cured resin, an uncured resin, or a volatile liquid can be formed on the surface of the film-forming medium. Such a coating once assists in uniformly depositing the powder on the surface of the film-forming medium and subsequently releasing the powder during mixing or stirring,
Apply a film to the part. This process causes the powder to adhere more evenly to the part.

The shape of the film forming medium is spherical, elliptical, cubic, triangular prism, cylinder, conical, triangular pyramid, quadrangular pyramid, rhombohedral,
Irregular shapes and other various shapes can be used.

The thickness of the uncured resin layer formed on the surface of the part depends on the size of the powder to be used. If this layer is too thin, the powder is difficult to adhere, so use a very fine powder of 0.1 μm or less. Sometimes at least 0.0
5 μm, preferably 0.1 μm or more is required. As the size of the powder becomes smaller, the thickness of the uncured resin layer may be smaller. When a powder having a particle size of 1 μm or more is used, the thickness of the uncured resin layer must be 0.5 μm or more. This layer may be formed on the entire part, or may be formed only on necessary parts.

The mixing ratio of the medium and the component depends on the shape of the component, but at least the apparent volume ratio of the medium is 20%.
Otherwise, uniform and sufficient impact on the surface of the component is not performed, and it is difficult to obtain a good film. The ratio of the flat powder to the other powder is 1 to 40% by volume, especially 3 to 30%.
It is preferably volume%.

As the vibrating container, various types of barrel machines usually used for polishing parts, such as a vibrating barrel, a centrifugal flow barrel, a rotary barrel and a gyro barrel, can be used. Further, the vibrating container is not limited to a pot type (open-top container), but may be a long cylindrical container. In the latter case, continuous processing can be performed and production line can be realized.

When the component is made of plastic, a solvent may be applied to dissolve the plastic of the member to form an adhesive layer. According to this method, since a film is formed only on the portion where the resin or the solvent is applied, it is very easy to form the film only on the inner surface of the plastic housing, for example.

[0039]

The flat powder used in the present invention, which is not melted by heating, has a flat shape and a melting point higher than the heating temperature, which contributes to the expected effect. The latter contribution is as follows. Prevents the coating from being deformed by the weight of the part when heated. In general, a substance having a high melting point has a high hardness at room temperature, so that the hardness of the film is increased. If only low melting point powder is used, the low melting point powder is likely to agglomerate or grow locally during vibration and agitation of parts having a film forming medium and an adhesive layer. However, when powders having a high melting point are present, aggregation of the low melting point powders and abnormal local film growth of the low melting point powders are suppressed.

The flat shape contributes to maximize the above. In other words, flat powder has a larger surface area than non-flat powder of the same volume, so it interrupts between low-melting powders and prevents agglomeration of these powders. As a result, the adhesive substance does not rise from the adhesive layer between these powders. In this case, film growth hardly occurs.

Thus, by using flat powder,
The growth of the film occurs mainly due to the adhesion of the powder by the adhesive substance creeping up from the adhesive layer. If the thickness of the adhesive layer is kept constant over the entire surface of the component, the powder grows. The amount of material trapped on the part is constant over the entire part surface. For example, in the case of a ring magnet, the thickness of the outer surface of the ring was much larger than the thickness of the inner surface of the ring without the addition of flat powder because the impact frequency of the film forming medium on the inner surface of the ring was smaller than that of the outer surface of the ring. Since the addition of the flat powder eliminates the swelling of the adhesive substance, the growth of the film stops after the ring outer surface reaches a certain thickness determined by the thickness of the adhesive layer. The growth of the film on the inner surface of the ring is slower than that of the outer surface, but with time, the film growth continues, and eventually stops at the same thickness as the outer surface (when the adhesive material disappears). Since the film thickness is controlled only by the amount of the adhesive layer without depending on the impact frequency of the film forming medium, the film thickness can be easily controlled.

[0042]

【Example】

Example 1 In a circular container having a volume of 3 liters and a depth of 150 mm, a diameter of 2 was placed.
A ceramic ball of mmφ was put in the container until the eighth minute. White epoxy resin powder (average particle size: 2 μm, uncured) obtained by pulverizing 50 μm powder of thermosetting powder coating for electrostatic coating (Teodur DM752-002 white, trade name, manufactured by Takashi Kubo Paint) into 2 μm (The same applies to the following Examples and Comparative Examples) and 20 g of a powder obtained by mixing aluminum foil powder (powder passing through 100 mesh) at a weight ratio of 9: 1 was added to the above-mentioned container, and 20 g was added to the container for 3 minutes. Vibration (frequency: 1000 to 4000 cpm, amplitude: 0.2 to 5 mm) was applied to spread the powder evenly on the surface of the ceramic ball.The vibration container was a barrel machine (Tipton Espo's vibration barrel machine VM-10 (230 W). )) Was used, and an inverter power supply and a slidac were used for vibration control.

Outer diameter 22mmφ, inner diameter 20mm while applying vibration
Nd-Fe-B super-quenched bonded magnet with φ, 10mm height and Nd-Fe-B with outer diameter 30mmφ, inner diameter 20mmφ, height 1mm
10 sintered magnets were mixed with an uncured epoxy resin (Eucoat 1001-B-80 manufactured by Yuka Shell Co., Ltd. and curing agent Epicure-UIZ-2 at a weight ratio of 10: 1. M) with 10% (by weight) dissolved
After dipping in the EK solution, it was taken out and dried with warm air for 30 seconds to form an adhesive layer. Next, the magnet on which the adhesive layer was formed was sequentially charged into the vibration container. After continuing the vibration for 5 minutes, all 20 parts were taken out. When these magnets were heated on a fluororesin plate at 150 ° C. for 2 hours, white epoxy resin powder was once melted and then started to harden (this process is hereinafter referred to as “melting-hardening process”). The epoxy resin powder as the adhesive layer was also cured.

The film formed in this manner has a uniform thickness of 20 μm ± 3 μm on both the inner and outer circumferences, and no difference in thickness between the components is observed. It was confirmed that the trace of contact with was barely small enough to be seen with the naked eye, and that the surface hardness was 5H (a hardness test using a pencil). As a result of observing the cross section of this film with an electron micrograph, it was found that aluminum flat powder was embedded almost parallel to the film surface.

COMPARATIVE EXAMPLE 1 As a comparative example, the same treatment was applied to the above parts without adding any aluminum foil powder.
50 μm, the outer periphery was extremely variable, 50 μm to 100 μm, the irregularities were severe, and large traces of contact between the lower surface and the lower plate during the melting-hardening treatment were observed. A burr protruded from the lower surface of the ring-shaped magnet tested, and the size of the burr exceeded an allowable range when used as a motor component and was required to be removed. The hardness of the film is from 3H to 4
H.

Comparative Example 2 As a comparative example, instead of aluminum foil powder,
The same treatment was applied to the above parts using a powder obtained by mixing titania powder having an average particle diameter of 1 μm (a shape close to a sphere) at the same weight ratio (9: 1 ratio with epoxy resin powder). The formed film has an inner circumference of 30 μm ± 7 μm and an outer circumference of 40 μm ±
The variation was large at 10 μm, and the unevenness was improved as compared with the case where nothing was added (resin powder alone), but the unevenness was larger than when aluminum foil powder was added. An intermediate contact trace between Example 1 and Comparative Example 1 was found on the contact surface between the lower surface and the lower plate during the melting-hardening treatment. The hardness was 5H.

EXAMPLE 2 A circular container having a volume of 3 liters and a depth of 150 mm was placed in a circular container having a diameter of 2 mm.
A ceramic ball of mmφ was put in the container until the eighth minute. In the container, a white epoxy resin powder (average particle size 2
μm), 20 g of powder obtained by mixing phlogopite powder (powder passing through 400 mesh) with a coupling treatment on the surface at a ratio of 8: 2 by weight is added, and the container is vibrated for 3 minutes (frequency: 4000 to 4000 cpm, amplitude). 0.2 to 5 mm), and the powder was evenly spread on the surface of the ceramic ball. As a vibration container, a barrel machine (VM-10 (230 W) manufactured by Tipton Espo) was used, and an inverter power supply and a SLIDAC were used for vibration control.

Nd having an outer diameter of 22 mm, an inner diameter of 20 mm, and a height of 10 mm
-Fe-B super-quenched bonded magnet and outer diameter 30mmφ, inner diameter
Ten sintered Nd-Fe-B magnets each having a diameter of 20 mm and a height of 1 mm were immersed in a MEK solution in which 7% of an epoxy resin was dissolved, taken out, and dried with warm air for 30 seconds to form an adhesive layer. Next, the magnet on which the adhesive layer was formed was sequentially charged into the vibration container. After continuing vibration for 10 minutes, all 20 parts were taken out. These magnets were subjected to a fusion-hardening treatment at 130 ° C. for 3 hours on a fluororesin net.

The coating thus formed has a uniform thickness of 25 μm ± 3 μm on both the inner and outer circumferences, and no difference in thickness between the components is observed. Was hardly observed, and the surface hardness was 5H (hardness test using a pencil). FIG. 1 shows an electron micrograph of the fracture surface of this film. It was found that flat powder of phlogopite was embedded almost parallel to the film surface.

COMPARATIVE EXAMPLE 3 As a comparative example, the same treatment was applied to the above-mentioned parts without adding any phlogopite powder, and as a result, the inner circumference was 35 μm to 55 μm in thickness.
m, and the outer periphery was extremely variable, 50 μm to 100 μm, the irregularities were severe, and large traces of contact between the lower surface and the lower plate during the fusion-hardening treatment were observed. The hardness was 3H to 4H.

Comparative Example 4 As a comparative example, titania powder having an average particle size of 0.8 μm (a shape close to a sphere) was mixed in the same weight ratio (ratio of epoxy resin powder and 8: 2) instead of phlogopite powder. The parts were subjected to the same treatment using powder. The formed film has an inner circumference of 35 μm ± 7 μm and an outer circumference of 45 μm ±
At 10 μm, there was a large variation, and the unevenness was improved as compared with the case where nothing was added (resin powder alone), but the unevenness was larger than the case where phlogopite powder was added. A slight trace of contact between the lower surface and the lower plate during the melting-hardening treatment was observed. Also,
The hardness was 5H.

Example 3 100 Nd-Fe-B sintered magnets having a diameter of 20 mm and a height of 1.5 mm were prepared. Divide this part into 20 parts each,
Samples A to E were used. Next, 2 mmφ ceramic balls and 20 g of aluminum foil powder (average particle size: 3 μm) were put into a circular container having a volume of 3 liters and a depth of 150 mm using the same vibration barrel machine as in Example 1, and placed in a container. 5
Minute vibration (frequency 3000-4000 cpm, amplitude 0.
5 to 2 mm), and the aluminum foil powder was spread evenly over the ceramic balls.

Samples A to D were prepared by adding 5% epoxy / ME
It was immersed in the K solution and dried to form an adhesive layer. Each of these samples A to D was placed in a vibrating container and vibrated for 10 minutes. In this way, a layer to which the aluminum foil powder was adhered in a layered manner (not cured) was formed. Next, the following processing was performed for each sample.

Sample A: First, the adhesive layer was cured at 150 ° C. for 2 hours. As a result, a layer in which the aluminum foil powder was strongly adhered to the magnet was formed. These magnets were immersed again in a 5% epoxy resin MEK solution and dried to form an adhesive layer on the surface of the aluminum foil film. These samples were placed in another container of the same size as the above container. A ceramic ball of 1 mmφ is put in the container in advance, and 25 g of white epoxy resin powder and 2.5 g of aluminum foil powder are added.
g was mixed well. Vibration (frequency 3)
000-4000 cpm, amplitude 1-10 mm) for 15 minutes. Thereafter, the sample was taken out and kept at 130 ° C. for 2 hours.
The epoxy resin powder applied by the second lamination was subjected to a melting-hardening treatment. As a result, a two-layer film of 8 μm in which the aluminum foil powder was adhered in layers and 15 μm of a mixed film of aluminum foil and epoxy resin was formed.

Sample B: The sample was subjected to a concentration without curing treatment.
It was immersed in a 10% epoxy resin MEK solution and dried to form an adhesive layer. These samples were placed in another container of the same size as the container. A ceramic ball of 2 mmφ is put in the container in advance, and 30 g of an epoxy-polyester resin powder (pulverized powder of 50 μm particle diameter of average particle size 2 μm, Toa Gosei Chemical Aron powder, powder E350 for electrostatic coating) is added. 3 g of aluminum foil was put and mixed well. Next, shake the container for 5 minutes (frequency 3000-
4000 cpm, amplitude 0.5-1 mm). Finally, a melting-hardening treatment was performed at 150 ° C. for 1 hour. As a result, a two-layer film of a film 8 μm in which aluminum foil powder was adhered in a layer and a film 12 μm of an aluminum foil and an epoxy-polyester resin mixed film was formed.

Sample C: The same curing treatment as that of Sample A was performed at 130 ° C. for 1 hour. These samples were put into a vibrating container without forming an adhesive layer, and vibrated for 10 minutes. The same container and ball as those used in the above sample B were used, and 30 g of the epoxy-polyester powder was added and mixed well. Finally, a heat treatment for melting and curing was performed at 150 ° C. for 2 hours. As a result, a film 8 μm in which aluminum foil powder was adhered in layers, an epoxy-polyester resin film 8 μm
m was obtained.

Sample D: The sample was put into the container used for Sample B (the same ball and powder were used) without subjecting the sample to a hardening treatment and forming an adhesive layer, and vibrated for 8 minutes. Was. Next, the sample was taken out and subjected to a fusion-hardening heat treatment at 160 ° C. for 2 hours. As a result, a film 8 μm in which aluminum powder was adhered in a layered manner, an epoxy-polyester resin film 7
A μm bilayer was formed.

Sample E: As a comparative material, an epoxy-polyester paint containing a white pigment was spray-coated on sample E by an average of 25 μm.

In the appearance inspection of Samples A to D, Sample A was the best, having smaller surface roughness, higher uniformity of film thickness and better adhesion of the film than Samples B, C and D. Samples A to above
E was subjected to a corrosion resistance test at 80 ° C. and 95% humidity. As a result, rusting, blistering, etc. were not observed in Samples A to D even after 1000 hours. However, in Sample E, spot rust was observed after 200 hours, and blistering of the film was observed after 500 hours.

[0060]

As described above, according to the present invention, there are no drawbacks of the conventional coating method, the surface is smooth, and the film thickness is excellent in uniformity. This makes it possible to form a simple film and to easily control the thickness of the film, which can greatly contribute to the field of coating technology.

[Brief description of the drawings]

FIG. 1 is a structural photograph showing the structure of a coating film of Example 2, particularly the deposition state of flat phlogopite mica powder.

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Osamu Itaya 1 Eri Part 2 401, Inter Metallics Co., Ltd., 22-22 Matsumuro Ouejo-cho, Nishikyo-ku, Kyoto-shi, Kyoto (58) Field surveyed (Int.Cl. ⁷ , DB name) C23C 26/00

Claims (1)

(57) [Claims] 1. A part to be treated having an adhesive layer on at least a part of its surface, and two or more kinds of powders having different melting points.
A powder mixture, and at least one of the high melting point powders has a flat shape and the mixed powder is substantially smaller in size than the part to be processed , and has a size substantially larger than the mixed powder. in a manner large film-forming medium, by applying vibration or stirring in a container, the surface of the part being processed,
Forming a film containing the mixed powder, and thereafter , forming the film at a temperature equal to or lower than the melting point of any of the flat powders, and
A method for forming a film, comprising heating the mixed powder to at least one of the melting points .