JP2000044842A - Powder coating material composition used for specific method for forming film and toning thereof and formation of film using the same powder coating material composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a powder coating material capable of readily carrying out stable toning even in a coating spot by using a powder coating material containing plural colored powder particles of different colors and to provide both a toning method and a method for forming a film by which the film of stable colors is obtained by using the composition. SOLUTION: This powder coating material is used for a method for forming a film comprising applying powder coating material particles through a film-forming medium to a material which is to be coated and has a preformed tacky layer and the powder coating composition containing colored powder coating material particles of different >=2 or more colors is obtained. The colored powder coating material particles preferably have 1-10 μm volume- average particle diameter and preferably are translucent particles. A flat powder is preferably contained in the powder coating material composition and the content thereof is preferably 5-50 wt.% based on the whole powder coating material composition. As a method for toning the powder coating material composition, the toning is preferably carried out by dry blending of the colored powder coating material particles of different colors. Furthermore, the powder coating material composition and the method for toning are applied to a method for forming the film by which the powder coating material can be applied through a film-forming medium to a material which is to be coated and has the preformed tacky layer on the surface to thereby simply and uniformly form the film of the stable colors.

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 coating film on a surface of an object to be coated such as various parts or articles used in a wide range of technical fields, and a coloring powder coating material used in the method. The present invention relates to a composition and a method for toning a powder coating composition.

[0002]

2. Description of the Related Art Electrostatic spraying, fluid immersion, electrostatic fluidizing immersion, and powder coating particles are applied to a surface of a workpiece through a film forming medium. There is known a method of forming a film to be attached to the surface of an object. However, powder coatings used in these film forming methods generally include a binder resin, a curing agent, an additive, a coloring pigment, and the like. It is manufactured by melt-kneading using, cooling the obtained melt-kneaded product, and then performing pulverization and classification. Therefore, the toning of the powder coating obtained by this method is limited to the method performed in advance by the type and amount of the coloring pigment used at the time of weighing, hue,
Toning of brightness and saturation (hereinafter also simply referred to as “color”)
This could not be done after the production of the powder coating.

[0003] It is extremely effective if the desired toned colored powder coating can be obtained simply by dry blending of the coloring pigment and the powder coating. However, in this dry blending method, the coloring pigment is usually used in the form of primary particles. The colored pigment is present in the form of agglomerated powder in the powder coating particles, so that when a film is formed using this colored powder coating, a uniform color is obtained. Film cannot be formed. As the next toning method, a method of mixing powder paint particles of different colors can be considered. However, in this method, it is necessary to make particles of different colors into fine particles to the extent that they cannot be visually discriminated, and the specific gravity and chargeability of the particles of the colored powder coating vary depending on the coloring pigment used. Occurs.

[0004] For example, since the specific surface area of the powder coating particles increases as the particles become finer, the fluidity of the powder coating particles significantly decreases, and as a result, the powder coating particles tend to adhere to each other. . Therefore, when a powder coating material having poor fluidity is used for the electrostatic spray powder coating, the adhesion of the powder coating particles to the inside of the hopper, the inner surface of the pipe, the tip of the spray gun, etc. of the coating machine proceeds. When the adhered amount reaches a certain amount or more, it is detached in a solid state and is called a "spit", that is, a coagulated powder having a diameter of about 1 to 5 mm is discharged from the spray gun and adheres to the object to be coated. However, a problem that a convex portion is formed on the surface frequently occurs. In addition, powder paint with poor fluidity does not enter the fluidized state (cloud state) due to fluidized air ejected from the perforated plate at the bottom of the hopper of the coating machine, so supply of powder paint to the spray gun is unstable. A phenomenon called "pulsation" occurs. It is impossible to perform uniform and stable coating using a powder coating material and a coating machine that generate this "pulsation".

[0005] Next, a problem when a powder coating material having poor fluidity is applied to the electrostatic fluidized immersion method will be exemplified. In the electrostatic fluidized immersion method, charged powder coating particles in a fluidized tank are fluidized using fluidized air jetted from a perforated plate at the bottom of the fluidized tank, and a grounding coating is applied to the fluidized state. This is a coating method in which particles of the powder paint are electrically attached by immersing objects, so if a powder paint with poor fluidity is used, the powder paint will not be in a fluidized state in the fluidizing tank. ,
Uniform and stable coating cannot be performed.

In general, powder coatings need to have fluidity in order to prevent the occurrence of “spits”, “pulsations” and “not in a fluidized state” as described above. The lower limit of the volume average particle size is about 10 μm even when a fluidity imparting agent or the like is added. However, when a mixture of colored powder coating particles of different colors having a volume average particle diameter of more than 10 μm is used, particles of each color can be visually identified, and a uniform color film cannot be obtained.

Further, powder coating particles using different coloring pigments are difficult to disperse uniformly in the air due to the difference in specific gravity of the particles, or in a hopper or a fluidized tank of a coating machine. Problems such as uneven product occur. Also,
In the case of powder coating particles using different coloring pigments, during electrostatic powder coating, color unevenness may occur due to selective adhesion at an edge portion and a flat portion due to a difference in chargeability. At present, there are the above-mentioned problems, and it is difficult to perform toning after manufacturing a powder coating.

[0008] At present, as a toning method after the production of a powder coating, Japanese Patent Publication No. 4-504431 and Japanese Patent Application Laid-Open No.
JP-A-188586 discloses a method for toning powder coatings
No. 143788 is known, but in order to avoid the above-mentioned problems, all of these powder coatings are manufactured in advance to produce fine colored powder coating fine particles so fine that the color of the particles cannot be visually identified. However, it is necessary to use it after granulating it to a particle size capable of electrostatic powder coating. Can't do color.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art, which are generally difficult after the production of a powder coating material, with respect to the toning of the powder coating material, and to prepare a powder coating material which has been manufactured in advance. A powder coating composition capable of easily performing stable toning even at a coating site using a body paint, a method for toning the same, and a stable color film can be easily obtained using the powder coating. An object of the present invention is to provide a method for forming a film that can be performed. Another object of the present invention is to apply a powder coating containing two or more colored powder coating particles and a toning method to form a film having various hues, lightness and saturation on an object to be coated. Is to provide a film forming method capable of easily and stably obtaining the film.

[0010]

Means for Solving the Problems As a result of intensive studies to solve the problems of the conventional film forming method and the powder coating as described above, the present inventors have found that the previously proposed film forming method (particularly, The present invention has been completed by finding a film forming method capable of easily obtaining a film having a uniform and stable color by a powder coating and a toning method suitable for use in Japanese Unexamined Patent Publication No. 5-302176).

That is, the powder coating composition of the present invention is used in a film forming method for adhering particles of a powder coating via a film forming medium to an object to be coated on which an adhesive layer is previously formed. A powder paint, characterized by containing two or more different colored powder paint particles. The colored powder coating particles preferably have a volume average particle diameter of 1 to 10 μm, and are preferably translucent particles. The powder coating composition preferably contains flat powder, and the content ratio of the flat powder is as follows:
The range of 5 to 50% by weight of the whole powder coating composition is preferred. Further, the powder coating composition preferably contains a fluidity-imparting agent. Further, the method for toning a powder coating composition of the present invention is characterized in that a powder coating composition containing colored powder coating particles of different colors is dry-blended. Furthermore, the film forming method of the present invention is characterized in that the above-mentioned powder coating composition is adhered via a film forming medium to the surface of the object on which the adhesive layer has been formed in advance.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. First, an explanation will be given using an apparatus used in the film forming method of the present invention. As an example of the method of forming a film in the present invention, as shown in FIG. 1, as shown in FIG. 1, an adhesive layer is formed on a surface of a container C disposed on a vibration device V with an uncured resin or another liquid or semi-liquid material. A mixture T such as the formed object to be coated W, the powder coating material, and a film forming medium to be described later is put therein.
Vibration is applied to the container C by the vibration device V to form a powder adhesion layer on the surface of the workpiece W.

The container C is made of a hard material such as a hard synthetic resin or metal. As an example, as shown in FIG. 1, the container C is formed in a bowl shape having an opening c1 at an upper portion. Then, a columnar portion c3 reaching the vicinity of the opening c1 is protruded by bulging a central portion of a bottom portion c2 of the container C upward. In FIG. 1, F is a frame of the vibration device V, and the frame F has a coil spring f.
A diaphragm f3 is arranged via the first and f2, and a columnar portion c3 of the container C is attached to an upper end portion of a vertical axis f4 protruding from the diaphragm f3. A motor f5 is attached to the lower surface of the diaphragm f3, and a weight f7 is eccentrically attached to an output shaft f6 of the motor f5. Therefore, by rotating the motor f5, the eccentric weight f7 is rotated, so that the container C is vibrated via the vertical axis f4 attached on the diaphragm f3. The containers of such a shaker coating machine are not limited to those having the shape or structure shown in FIG. 1, and various containers such as a cylindrical container, a box-shaped container or a spiral tubular container are used. it can.

In the method of forming a film of the present invention, an external force such as rotation or dropping can be used as in a ball mill or a V-blender, instead of vibrating the container. The viscous body is placed in the container and the mixture is vibrated to form a film on the object to be coated, or the mixture is agitated with a blade to form a powder coating composition on the adhesive layer. An object can be attached.

In the present invention, the powder coating composition in the coating machine is vibrated together with the film-forming medium and the object to be coated, so that the film-forming medium plays a role of a pulverized ball of a ball mill and is different. While uniformly dispersing and mixing a powder coating composition containing colored powder coating particles of two or more colors (hereinafter simply referred to as “colored particles”), a film is formed on the adhesive layer formed on the object to be coated. Particles of the powder coating composition (hereinafter simply referred to as “powder particles”) adhere via the forming medium. Next, the adhered powder particles are beaten by the film-forming medium, and are pressed or pressed into the adhesive layer to be firmly adhered. Then, the pressure-sensitive adhesive is extruded onto the surface of the powder particle adhesion layer by being further hit by the film-forming medium, and the powder particles further adhere to the extruded pressure-sensitive adhesive via the film-forming medium. Thus, the adhesion of the powder particles to the surface of the object to be coated proceeds. Then, even if the powder particle adhesion layer on the surface of the object to be coated is hit by the film forming medium, the point at which the pressure-sensitive adhesive is no longer extruded onto the surface of the powder particle adhesion layer, The attachment process will end. The powder particle adhesion layer thus formed has the advantage that the powder particles composed of colored particles of two or more colors are uniformly dispersed and filled in multiple layers and at a high density. It is possible to form a film having a uniform film thickness and a stable color even on concave and convex portions of an object to be coated having various shapes.

The objects to be coated used in the film forming method of the present invention include, for example, parts of various machine tools, vehicles, ships, airplanes, etc., home electric parts, electric / electronic parts, office equipment parts, furniture, building materials, decorations. Examples include supplies, hardware, magnets, toys, and the like, but are not limited thereto. And as the material of these objects to be coated, not only various metals,
Conventionally, insulating materials such as ceramics, glass, plastic, wood, paper, and inorganic compounds, for which electrostatic powder coating has been considered difficult, can also be used.

In the present invention, an adhesive layer made of an adhesive having an adhesive force necessary for adhering the powder particles must be formed on the surface of the object to be coated in advance. As the adhesive, an uncured liquid or semi-liquid resin, as well as other general liquid or semi-liquid substances can be used. The binder component of the pressure-sensitive adhesive is not limited to known liquid or semi-liquid resins such as epoxy resin, acrylic resin, polyester resin, phenol resin, amino resin, silicone resin, and urea resin. Known liquid or semi-liquid substances such as glycols, tars, and monomers, oligomers, and polymers such as styrene, acrylic, phenol, and isocyanate can also be used. These binder components can be used alone or as a blend of two or more, and in order to adjust the adhesive strength, it is also possible to use a blend of a solid and a liquid. is there. further,
It is also possible to dissolve a solid resin or the like in a solvent having a high boiling point such as cyclohexanone and use it in a tack-dry state.

Further, the above-mentioned binder component may be a hydroxyl group, an epoxy group, an amino group, a carboxyl group, an isocyanate group,
When having a functional group such as an aldehyde group, a nitro group, and a sulfone group, a substance capable of causing a cross-linking reaction with the functional group, for example, a known resin such as a phenol resin or a polyamide resin, or an imidazole, Imidazolines, acid anhydrides, hydrazines, amines, amides,
It is preferable to add a known curing agent such as a dibasic acid, isocyanate, or isocyanurate, or a curing catalyst to the pressure-sensitive adhesive as needed. As the pressure-sensitive adhesive, those having excellent compatibility with the powder coating melted at the time of heat treatment and good adhesion to an object to be coated are preferable, so that various pressure-sensitive adhesives such as coupling agents and surfactants are used. Additives may be added as appropriate.

To form the adhesive layer, the object to be coated is immersed in the adhesive, the adhesive is sprayed on the object by spraying or the like, or the adhesive is applied to the object with a brush or a roller. Can be performed. At this time, if the adhesive component has a high viscosity, a common diluent such as ethers, alcohols, ketones, and aromatic compounds may be added for dilution. In addition, the thickness of these pressure-sensitive adhesive layers affects the amount of powder particles attached, and is appropriately adjusted according to the viscosity and pressure-sensitive adhesive strength of the pressure-sensitive adhesive, the particle diameter of powder particles and a film-forming medium, the material, and the like. Is preferred.

The film-forming medium used in the present invention exerts a function of generating a striking force to uniformly disperse and mix the powder particles, and to uniformly adhere the powder particles to the adhesive layer. It must not adhere to the adhesive layer itself. Therefore, a medium having a size substantially smaller than the object to be coated and substantially larger than the powder particles is used as the film forming medium. In the case of a film forming medium larger than the object to be coated, a uniform impact cannot be applied to the surface of the object to be coated, and a film forming medium smaller than the powder particles is preferably taken into the adhesive layer. Absent.

It is important that the material of the film forming medium satisfies the following conditions. In other words, there is no significant change in shape as observed with the naked eye by observing the film forming medium after film formation, and elastic deformation does not become extremely large during the film forming process. I can't, but crack, chip,
It is important that rapid wear does not occur. If a film-forming medium that does not meet these requirements is used, the film-forming medium will undergo plastic deformation or large elastic deformation due to collision with the object to be coated.
Since the impact force applied to the object to be coated is insufficient or uneven, the desired film formation does not occur. Also, if cracks or chips occur, the fragments are taken into the powder adhering layer and cause film defects such as protrusions, which is not preferable.

As the material of the film forming medium, for example,
Iron, carbon steel, other alloy steels, copper ore and copper alloys, aluminum and aluminum alloys, various other metals, or Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , SiC
Ceramics, glass, various plastics, various rubbers, wood, and the like can be used. The material and size of these film forming media are appropriately selected according to the shape and size of the object to be coated, the particle size and material of the powder particles, and the like. Further, a plurality of film forming media of different materials and sizes can be used in combination, or the film forming medium can be used after being subjected to surface treatment, surface coating, and the like. Furthermore, a composite film forming medium composed of a plurality of the above-mentioned materials may be used. The shape of the film forming medium is
For example, spherical, elliptical, cube, triangular prism, cylinder, cone,
Triangular pyramids, quadrangular pyramids, rhombohedrons, amorphous bodies, and various other things can be used, and those of these shapes alone,
Alternatively, they can be used by appropriately mixing.

In the present invention, after the powder particles are adhered to the pressure-sensitive adhesive layer by the above-mentioned method, the object to be coated and the film-forming medium are separated, and the powder particles are subjected to a heat treatment at a predetermined temperature for a predetermined time so that the powder particles are removed. Melts to form a film. Here, the predetermined time at the predetermined temperature is a temperature determined by the constituent material of the powder particles and the material of the object to be coated. In other words, when the colored particles are thermosetting, the object to be coated does not melt and deform, and the temperature and time are such that the functional group of the binder component sufficiently reacts with the curing agent. In the case of a thermoplastic material, the temperature is not less than the melting point of the powder particles and is an arbitrary temperature and time without the object to be coated being melted and deformed.

Next, the powder coating of the present invention will be described in detail. The powder coating composition of the present invention is a powder coating used in a film forming method of attaching a powder coating via a film forming medium to an object to be coated on which an adhesive layer is previously formed, One containing two or more colored powder coating particles, that is, one containing a plurality of colored particles having different colors.

First, the colored particles which are one of the components of the powder coating composition of the present invention will be described in detail. The colored particles contain at least a binder resin. Examples of the binder resin include powders such as epoxy resin, acrylic resin, phenol resin, amino resin, xylene resin, urea resin, melanin resin, and polyester resin. The resins used in the paint can be used alone or in combination. When the binder resin is a thermosetting resin, a curing agent containing a functional group capable of performing a crosslinking reaction with a functional group contained in the thermosetting resin may be used. As the curing agent, for example, amines, amides, dicyandiamides, acid anhydrides, isocyanates, polysulfides, acid dihydrazides, imidazoles and other curing agents commonly used in powder coatings can be used alone. Or mixed.

The coloring particles include various fillers such as calcium carbonate, barium sulfate, talc, silica, alumina and aluminum hydroxide, various spreading agents such as esters and silicones, and various foaming inhibitors such as benzoin. In addition, various additives such as a wax, a coupling agent, an antioxidant, an antibacterial agent, and an ultraviolet absorber may be appropriately added as needed.

Further, the colored particles used in the present invention include:
Preferably, the particles are translucent particles. The translucent particles referred to in the present invention refer to those in which the proportion of the coloring pigment contained in the colored powder coating of each color is 10% by weight or less, and also includes clear. Further, in a film formed using a powder coating containing two or more colored particles in which the proportion of the colored pigment exceeds 10% by weight, the difference in color becomes clear at the outline of the colored particles of different colors, and visual observation is performed. Thus, it is easy to identify the difference in color, and it is necessary to reduce the particle size. On the other hand, in a film formed using a powder coating containing colored particles having a color pigment ratio of 10% by weight or less, the outline of the colored particles of different colors is blurred, and the color is distinguished by the so-called "blur" effect. Is difficult, which is preferable.

Examples of the coloring pigment include organic pigments such as phthalocyanine, azo pigments and condensed polycyclic pigments, and inorganic pigments such as titanium dioxide, carbon black, graphite, and red iron oxide. Known pigments or dyes used can be used. Regarding the color of the coloring pigment, for example, red, blue, green, yellow, white, black, brown, violet,
Any color pigment such as orange may be used,
In particular, using colored particles of a total of six colors obtained by adding clear to five colored particles containing five colored pigments of yellow, cyan, magenta, black, and white, By dry-blending the variously modified ones, it is preferable because colors of desired hue, lightness and saturation can be almost mixed.

The raw materials comprising the binder resin, the coloring pigment, the curing agent, the additives and the like are weighed, preliminarily mixed by using a mixer or a blender, and then melt-kneaded by a kneader and cooled. Thereafter, the particles are pulverized using a mechanical or air-flow type pulverizer to obtain colored particles. Further, the production of the colored particles is not limited to the above-mentioned method at all, and can be produced by, for example, a spray drying method or a polymerization method.

The colored powder coating particles used in the powder coating composition of the present invention preferably have a volume average particle diameter of 1 to 10 μm. The two or more different colored particles are suitable for obtaining a uniform color film because the smaller the volume average particle diameter becomes, the more difficult it is to visually discriminate the different color particles. When the diameter is smaller than 1 μm, the productivity of the colored particles is extremely reduced, which is not preferable. Also, the maximum volume average particle diameter that can visually identify the difference in the color of the colored powder coating particles is affected by the difference in two or more colors to be mixed, and is light and dark, and light and dark. And the like, and become smaller when the similar colors are mixed with each other, but if it is 10 μm or less, it is difficult to visually distinguish the color difference of the colored particles. For these reasons, the volume average particle diameter of the colored particles is 1 to 10 μm.
m is preferred, more preferably 2 to 8 μm, and most preferably 3 to 5 μm. The volume average particle size of the particles used in the present invention is measured using a laser diffraction type particle size distribution analyzer (Microtrack, manufactured by Nikkiso Co., Ltd.).

The powder coating composition of the present invention preferably contains flat powder. This flat powder is mainly used for reflecting light. This flat powder that reflects light has the effect of a white pigment that reflects light in the coating and improves the whiteness of the coating, the effect of a concealing aid that conceals the surface of the object to be coated, and powder particles. It has a leveling aid function to smooth the surface of the adhesion layer.

First, the action of the flat powder as a white pigment is adjusted by using, for example, four color powder coating particles of yellow, magenta, cyan and black which do not contain a white pigment represented by titanium dioxide. When performing color, the flat powder reflects light, acts as if it were white paper of full color printing, and tones to various colors like full color printing by superimposing four colored particles on it It is preferable because it can be used.

Next, as an effect of the flat powder as a hiding auxiliary material, for example, when a film is formed using translucent colored particles having the above-mentioned “blur” effect, the film thickness becomes thin. If the base material is easily transparent due to insufficient hiding power, however, it is preferable to have light-reflecting flat powder in the film because the hiding power can be improved.

Next, as a leveling aid function, as described above, in the film forming method of the present invention, when a powder coating containing flat powder is used, the film forming medium converts the powder particles into flat powder. Tap together on the adhesive layer. At that time, if the colored particles are sufficiently smaller than the flat powder, the flat powder adheres parallel to the surface of the object to be coated, and as a result, the smoothness of the surface of the powder particle adhesion layer is improved. . Further, when the flat powders are arranged horizontally in the film, there is an advantage that the action as a white pigment and the action as a hiding aid are increased, which is very effective. because of these reasons,
The powder coating of the present invention preferably contains a flat powder that reflects light.

As the flat powder used in the present invention, those which reflect light are preferable, and specifically, powders of various metals such as aluminum, titanium, stainless steel, nickel, copper, brass, silver, gold, palladium and the like. Or, in addition to these alloy powders, mica powder, glass powder and the like can be mentioned. As these flat powders, those subjected to a known surface treatment such as coupling treatment, resin coating, metal plating, and the like, and those colored with a coloring pigment or the like can be suitably used. These flat powders that reflect light may be used alone or in combination of two or more. The flat powder referred to in the present invention refers to a thing in which a solid is crushed between surfaces and has a flat surface as compared with a sphere or an irregular shape, and has a distortion, a warp, a curve, Irregularities may be present, and the opposing surfaces may not necessarily be parallel.

The volume average particle diameter of the flat powder is 5 to 1
It is preferably in the range of 00 μm, more preferably 5 to
50 μm. When the volume average particle diameter is less than 5 μm, the particle diameter of the colored particles relative to the flat powder becomes relatively large, so that the direction of the flat powder becomes uneven in the powder particle adhesion layer, and This is not preferable because the three functions and effects of the above are reduced. On the other hand, when the volume average particle diameter is 1
If the particle size is larger than 00 μm, both the flat portion and the thickness of the flat powder become large, and it is not preferable because a coarse film can be visually observed. The ratio of the flat powder to the powder coating is preferably 5 to 50% by weight. If the ratio of the flat powder is less than 5% by weight, the above three effects of adding the flat powder cannot be sufficiently exhibited. On the other hand, if it exceeds 50% by weight, the flat powder is likely to be detached from the film after the heat treatment, which is not preferable.

The colored particles of two or more colors contained in the powder coating composition of the present invention must be uniformly mixed. In order to uniformly mix the colored particles, the above-mentioned raw materials of the powder coating composition containing two or more colored particles are appropriately weighed, and dry-blended using a mixer or a blender to obtain a desired mixture. An excellent powder coating composition toned in color can be obtained easily and easily. If the mixing is carried out by a wet mixing method, a step of drying the powder coating is required, which undesirably lowers the working efficiency.

The powder coating composition of the present invention further comprises:
If necessary, as a fluidity imparting agent / dispersing aid, an inorganic substance such as ultrafine silica particles or alumina ultrafine particles, an acrylic cross-linked resin fine particle, a methyl silicone resin fine particle, or an organic substance represented by a metal soap, etc. By adding ultrafine particles or the like, the fluidity and dispersibility of the powder particles can be improved.

[0039]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and the like, but the present invention is not limited to these Examples. Example 1 (Production of colored powder coating particles) Yellow colored particles Polyester resin 85.0 parts by weight (trade name: ER-6680, manufactured by Nippon Ester Co., Ltd.) 15.0 parts by weight of blocked isocyanate (trade name: B- 1530, manufactured by Daicel Huls Co., Ltd. Flow-off agent (butyl acrylate) 1.0 part by weight Antifoaming agent (benzoin) 0.5 part by weight Color pigment 5.0 parts by weight (trade name: YELLOW HG VP2155, Hoechst) After mixing the raw materials having the above mixing ratios with a supermixer, melt-kneading them in a kneader under a temperature condition of 100 ° C., cool them, and then pulverize them with a pulverizer to obtain a volume average particle diameter. 3.0 μm yellow colored particles were obtained.

The magenta-based coloring particles were mixed with magenta-based coloring pigments (trade name: EOR-186T, manufactured by Dainichi Seika Kogyo Co., Ltd.).
Except that the amount was changed to 0 parts by weight, magenta colored particles having a volume average particle diameter of 3.0 μm were obtained by the same method using the same raw materials as described above. In the compounding components of the cyan-based colored particles, the same procedure was performed using the same raw materials except that the colored pigment was changed to 5.0 parts by weight of the cyan-based colored pigment (trade name: KET BLUE 118, manufactured by Dainichi Seika Kogyo). According to the method of volume average particle diameter 3.0μ
m cyan colored particles were obtained. In the compounding components of the white colored particles, except that the colored pigment was changed to 10 parts by weight of a white colored pigment (trade name: CR-90, manufactured by Ishihara Sangyo Co., Ltd.), a similar method was performed using the same raw materials as described above. White colored particles having a volume average particle diameter of 3.0 μm were obtained.

The same ingredients were used except that the coloring pigment was changed to 1 part by weight of black coloring pigment (trade name: MA-100, manufactured by Mitsubishi Kasei Co., Ltd.). By the method, black colored particles having a volume average particle diameter of 3.0 μm were obtained. Clear colored particles having a volume average particle diameter of 3.0 μm were obtained in the same manner using the same raw materials as in the above, except that no coloring pigment was added to the components of the clear colored particles.

(Production of powder coating) As shown in Table 1, two or more colored particles obtained by mixing the colored particles obtained in the above (1) and (2) at the mixing ratios shown in A to D were used. Parts by weight and 1.0 part by weight of alumina fine particles (trade name: Aluminum Oxide C, average particle size: 21 nm, manufactured by Nippon Aerosil Co., Ltd.) as a fluidity-imparting agent, respectively, by stirring and mixing using a Henschel mixer. Powder coatings A to D were obtained. Further, 100 parts by weight of two or more colored particles shown in Table 1 mixed at a compounding ratio of E to G, and 10 parts by weight of aluminum flat powder (trade name: HR-51, manufactured by Asahi Chemical Industry Co., Ltd.) Alumina fine particles (trade name: Aluminum Oxide
C, average particle size: 21 nm, manufactured by Nippon Aerosil Co., Ltd.)
And 0 parts by weight using a Henschel mixer with stirring to obtain powder coatings EG. As the aluminum powder, a commercially available aluminum powder to which solvents such as mineral spirits and petroleum naphtha were added, was used after removing these solvents by vacuum drying.

[0043]

[Table 1]

(Formation of Film) Using each of the powder coatings A to G shown in Table 1, a film was formed by the following method. A 0.8 mm thick SPCC steel plate (trade name: PB-137M, manufactured by Nippon Test Panel Co., Ltd.) was used for the object to be coated.
What was cut into mm × 50 mm was used. As the adhesive, a liquid epoxy resin (trade name: Epicoat 8)
28, Yuka Shell Epoxy Co., Ltd.) and curing agent (Product name: C)
11Z, manufactured by Shikoku Kasei Kogyo Co., Ltd.) at a ratio of 95: 5, and the mixture was diluted with ethanol (solid concentration:
5% by weight). Place the object to be coated in this adhesive solution
After immersion for 0 second, it was taken out and the diluent was dried and removed with warm air of a dryer to obtain an SPCC steel sheet having an adhesive layer formed on the surface.

The coating machine has the same structure as that of FIG. 1, and its container C has a capacity of 2.8 liters and a depth of 150 m.
m was arranged at an angle of 30 degrees from the vertical direction. In addition, iron powder coated with urethane rubber and having a diameter of about 0.8 mm was used as a film forming medium. First, container C
Was charged with 1200 g of the iron powder and 7.0 g of the powder coating A, and then the container C was shaken for 5 minutes to uniformly mix the powder coating A and the iron powder. Next, the SPCC steel sheet having the adhesive layer formed on the surface was charged into the container C and vibrated for 3 minutes, so that the powder coating material A was attached to the adhesive layer of the SPCC steel sheet. Then, the SPCC steel sheet is taken out of the container C,
This was placed in a hot air drying furnace and subjected to a heat treatment at 180 ° C. for 20 minutes, so that the SPC having the powder coating A film formed thereon was formed.
C steel plate was obtained. In this way, a film of the powder coating material A was formed on the surfaces of the three SPCC steel sheets. An SPCC in which three layers of powder coatings B to G were formed in the same manner except that the powder coating A used for forming the coating was replaced with powder coatings B to G, respectively. A steel plate was obtained.

(Evaluation of coating) Each of the obtained SPCs
Regarding the film formed on the surface of the C steel sheet, the distinction of the color difference between a plurality of colored particles having different colors, the uniformity of the color of each film, the color stability of the three films, and the smoothness of the surface The properties were evaluated by visual observation. Incidentally, the visual evaluation in the present invention, the distance between the film and the eye was 20 cm
The test was performed by a person having a normal eyesight of 1.2 or more.

Comparative Example 1 A magenta colored pigment (trade name: EOR-186T, 100 parts by weight) was added to 100 parts by weight of the yellow colored particles obtained in Example 1.
3.0 parts by weight (made by Dainichi Seika Kogyo Co., Ltd.) and alumina fine particles as a fluidity imparting agent (trade name: Aluminum Oxi)
de C, average particle size: 21 nm, manufactured by Nippon Aerosil Co., Ltd.)
The powder coating was obtained by stirring and mixing 1.0 part by weight with a Henschel mixer. Using this powder coating, a film was formed on three objects to be coated in the same manner as in Example 1.

Comparative Example 2 Using the powder coating material A, an attempt was made to form a film by the following method using a corona charging type electrostatic spray gun (trade name: GX-108, manufactured by Chichibu Onoda). An SPCC steel plate having a thickness of 0.8 mm and a size of 70 mm × 150 mm (trade name: PB-137M, manufactured by Nippon Test Panel Co., Ltd.) was used as the object to be coated. 300 g of powder coating material A is put into a hopper of a coating machine, applied voltage is 60 KV, and pattern adjustment is 1.0 kgf / c.
m ² , 1.5kgf / cm ² empty space, 2.0k discharge rate
gf / cm ² , flowing air 2.0 kgf / cm ² , and the distance between the object to be coated and the tip of the gun was maintained at 20 cm. When the coating was performed, the powder coating did not become fluidized in the hopper. The powder coating cannot be supplied and conveyed stably to the spray gun, so that "spits" and "pulsations" occur, and a large number of agglomerated powders having a diameter of about 1 to 5 mm (hereinafter described) Island) has adhered.
This could not be improved by changing the conditions of the coating machine.
Further, the powder coating material adhering to other places was in the form of a sponge (sea described later) in which a large amount of air was caught, and was far from fine packing. This is presumed to be due to the fact that the powder coating particles are not dispersed to the primary particles by the carrier air, but adhere to the object to be coated in the form of secondary aggregated powder. In this case, the powder adhesion layer on the object to be coated was in a sea-island structure in which islands of agglomerated powder floated in a sponge-like sea. In order to observe the film after heat treatment, the three coated objects coated under the above-mentioned coating conditions were placed in a hot-air drying furnace and heat-treated at 180 ° C. for 20 minutes to form a film. The evaluation of the film was performed according to Example 1.

Comparative Example 3 An electrostatic fluidized dip coating machine (trade name: C
-30, ELECTROSTATIC TECHNOLO
GY INC. (Manufactured by K.K.) in the following manner. When the fluidizing air flow rate of the coating machine was set to 40 L / min and 100 g of powder coating material A was charged into the fluidizing tank,
Since the powder coating did not become fluidized at all in the fluidized tank, the powder coating could not be attached to the object to be coated. And even if the flow rate of the fluidizing air was changed, the powder coating in the fluidizing tank could not be fluidized. for that reason,
With the electrostatic fluidized immersion coating machine, a film could not be formed on the object to be coated.

Table 2 shows the evaluation results of the films obtained in the above examples.

[Table 2]

In the film of Example 1 using the powder coatings A to G, it was not possible to visually identify particles having different colors irrespective of the mixing ratio of the colored particles having different colors. The color uniformity of each film, the color stability of the three films, and the smoothness of the films were also good. On the other hand, Comparative Example 1
In the film (1), the agglomerated powder of the magenta coloring pigment can be visually confirmed, and the color is clearly different between the first and third coatings. This is presumably because the magenta color pigment dry-blended with the yellow color particles was gradually dispersed in the container during the film formation due to the impact force of the film forming medium, and the color changed over time. . In the film of Comparative Example 2, a uniform color was obtained. However, since the powder particle adhesion layer before the heat treatment had a sea-island structure due to "poor dispersion of the powder coating by the carrier air" and "spits" and "pulsations", the film after the heat treatment had a A large number of islands having a diameter of about 1 to 5 mm are present in the skin-like sea and cannot be used. In Comparative Example 3, a film could not be formed on the object to be coated.

[0052]

According to the present invention, there is provided a powder coating composition comprising a powder coating composition containing at least two or more different colored powder coating particles, which is adhered to an adhesive layer via a film forming medium. By using, the toning after the production of the powder coating, which has been difficult with the conventional technology, can be performed easily and stably even at the painting site, and this has been an issue of the colored powder coating. Toning can be performed easily,
Very useful industrially. Further, by applying a powder coating containing two or more colored powder coating particles and a toning method to the coating forming method of the present invention, a coating having various hues, lightness, and saturation can be formed on an object to be coated. It can be easily and stably formed thereon.

[Brief description of the drawings]

FIG. 1 is a schematic view of an example of a coating machine for forming a film using the powder coating material of the present invention.

[Explanation of symbols]

C: container, c1: opening, c2: bottom, c3: columnar part,
V: shaker, F: machine, f1 and f2: coil spring, f3: diaphragm, f4: vertical axis, f5: motor,
f6: output shaft, f7: weight, T: mixture, W: object to be coated.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Osamu Itaya 1-2-1 Eripart 2 401, Matsumuro-Ojocho, Nishikyo-ku, Kyoto-shi, Kyoto (72) Inventor Akira Fujiwara For Shizuoka-shi, Shizuoka No. 3-1 Sompocho F-term in the Chemical Products Division of Hamakawa Paper Co., Ltd. 4D075 BB16X EA02 EB56 EB57 4J038 DB001 EA011 KA08 KA20 MA02 MA14 PA02 PA07

Claims (9)

[Claims] 1. A powder paint used in a film forming method for adhering particles of a powder paint via a film forming medium to an object to be coated on which an adhesive layer has been formed in advance.
A powder coating composition comprising colored powder coating particles of a color or more. 2. The colored powder coating particles having a volume average particle diameter of 1
The powder coating composition according to claim 1, which has a particle size of from 10 to 10 m. 3. The powder coating composition according to claim 1, wherein the colored powder coating particles are translucent particles. 4. The powder coating composition according to claim 1, further comprising a flat powder. 5. The powder coating composition according to claim 4, wherein the content of the flat powder is in the range of 5 to 50% by weight of the whole powder coating composition. 6. The powder coating composition according to claim 1, further comprising a fluidity-imparting agent. 7. A method for toning a powder coating composition, which is used in a method for forming a coating film, in which a powder coating material is adhered via a film forming medium to an object to be coated on which an adhesive layer has been formed in advance. A method of toning a powder coating composition, comprising dry blending a powder coating composition containing two or more colored powder coating particles. 8. A method for toning a powder coating composition according to claim 7, wherein the powder coating composition according to claim 1 is used. 9. The powder coating composition according to any one of claims 1 to 6, wherein the powder coating composition according to any one of claims 1 to 6 is attached via a film forming medium to a surface of the object on which an adhesive layer has been formed in advance. Film formation method.