JPH09302272A - Powder coating material for forming uneven pattern, its production, and coated article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a coating film which has a soft satiny uneven pattern excellent in terms of design and formed by uniform fine minute round projections. SOLUTION: A powder coating material comprising 60-99.9wt.% thermosetting component contg. a thermosetting resin which is solid at normal temp. and 0.1-40wt.% resin beads having an average bead size of 10-200μm and has a shape stability at the thermal curing temp. of the foregoing component is applied to an object 2 to form a coating film 4 having a thickness not higher than the average size of the beads 5, thus forming an uneven coating film 3 having a pattern formed by roundish projections 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder coating material for forming a satin-like uneven pattern having a soft and high design property, a method for producing the same, and a coated article.

[0002]

2. Description of the Related Art In recent years, as application development of powder coating materials has progressed, there has been an increasing demand for powder coating materials having a design property with the diversification of decorative expressions on objects to be coated. Under such circumstances, there is provided a powder coating material that changes the basic tone of the material, for example, forms an uneven pattern such as a matte tone, a velvet tone, a suede tone, and a hammer tone finish to impart design characteristics. As a method of forming such a concavo-convex pattern, for example, by using an additive such as a silicon compound, a unique cissing-like concavo-convex pattern is formed on the surface of the coating film, and the designability can be imparted.

Another method is to form a concavo-convex pattern by mixing resins having different characteristics into powder coating. For example, JP-B-48-7686 has an average particle size of 200 mesh or less and 100 to 25.
A resin powder that has a melt viscosity at 0 ° C. of 100 poise or less and is solid at room temperature, and a resin powder that has an average particle size of 60 mesh or more and less than 200 mesh and that has a melt viscosity at 100 to 250 ° C. of 100 poise or less and is solid at room temperature. There is disclosed a powder coating material characterized by a mixed uneven pattern. However, the coating film formed by this powder coating has shallow irregularities,
It becomes orange peel (ORANGE PEEL) and has poor design. Further, this method has a defect that the expression pattern of the obtained coating film changes depending on the coating conditions and the use of recovered powder.

As another method, a method in which a specific resin is dispersed in a main resin of a powder coating material to form a coating material is already known. For example, JP-A-60-258270 discloses a mixture containing a thermosetting resin which is solid at room temperature and a thermoplastic cellulose ether resin powder, in which the thermosetting resin melts but the thermoplastic cellulose ether resin dissolves. There is disclosed a powder coating material which is kneaded at a temperature not controlled, cooled and then finely pulverized. However, in this powder coating, since the thermosetting resin and the thermoplastic cellulose ether resin are kneaded at the same temperature, it is not possible to obtain a sufficient dispersion of the thermoplastic cellulose ether resin. In addition to the lack of uniformity, the coating film had a problem that it had a phenomenon of reaching the base material and lacked in corrosion resistance.

[0005]

The designable coating film obtained by these various methods is limited to the expression of designability by forming a continuous irregular asperity pattern on the surface of the object to be coated, and a pattern of different tones can be obtained. Has not been done. However, there is a demand for a soft, highly moisturized coating film having a high design, centering on OA equipment and measuring equipment.

In order to meet such a demand, an object of the present invention is to form a satin-like uneven pattern having a soft and high design, which is represented by a uniform, precise, and minute rounded projecting pattern. It is an object of the present invention to provide a pattern-forming powder coating material, an efficient manufacturing method thereof, and a coated article formed by the method.

[0007]

The present invention is the following method for producing a powdery coating material for forming an uneven pattern and its coated article. (1) (A) 60 to 99.9% by weight of a thermosetting powder coating material component containing a thermosetting resin that is solid at room temperature, and (B) an average particle size of 10 to 200 μm, and A concavo-convex pattern-forming powder coating material, which contains 0.1 to 40% by weight of resin beads whose shape is stable at a heating and curing temperature. (2) Resin beads are polyamide resin, polyolefin resin, acrylic resin, epoxy resin, polyester resin,
The powder coating according to (1) above, which is at least one selected from polyurethane resin, melamine resin, and resin beads composed of a thermoplastic resin and a thermosetting resin obtained by three-dimensionally crosslinking these resins. (3) (A) 60 to 99.9% by weight of a thermosetting powder coating material component containing a thermosetting resin that is solid at room temperature, and (B) an average particle size of 10 to 200 μm, and (A) 0.1 to 40% by weight of resin beads whose shape is stable at the heat curing temperature is heated to a temperature at which the resin component in the component (A) is melted to disperse the component (B) in the component (A). A method for producing a powder coating composition capable of forming an uneven pattern, which comprises: (4) The powder coating composition according to (1) or (2) is applied to an object to be coated so that the cured coating film of component (A) has a film thickness not exceeding the average particle size of component (B). Formed coated object.

The powder coating composition for forming uneven patterns of the present invention comprises
It contains a thermosetting powder coating component as the component (A) and resin beads as the component (B). The thermosetting powder coating material component (A) contains a thermosetting resin solid at room temperature and other components added as necessary, and has been conventionally used as a thermosetting powder coating material. The ingredients can be used as they are.

In the powder coating material of the present invention, the thermosetting resin which is solid at room temperature and is used as the component (A) is not particularly limited, but it is used as a coating film forming component in the conventional thermosetting powder coating material. Known thermosetting resins such as a self-crosslinking type, a curing agent-containing type, and a curing agent post-addition type can be used. As a general example of such a thermosetting resin, for example, epoxy-based, polyester-based, acrylic-based, fluorine-based, etc. solid thermosetting resins that are solid at room temperature are preferably used as the main agent, and melamine as a curing agent, Blocked isocyanates, polybasic acid / amides, glycidyl compounds, polymers thereof and the like can be used.

The component (A) may be added as other components in an amount of 0.01 to 10 relative to 100 parts by weight of the thermosetting resin.
The pigment can be added in the range of 0 parts by weight. As the pigment, inorganic pigments such as titanium dioxide, carbon black and iron oxide, extender pigments such as talc, precipitated barium sulfate, silica and calcium carbonate, and organic pigments such as cyanine blue azo pigment can be used. Further, as in the conventional powder paint, other components such as a curing accelerator, a leveling agent, a defoaming agent, an antioxidant, a modifier such as an ultraviolet absorber, and other additives are added to 100 parts by weight of the thermosetting resin. On the other hand, it can be added in the range of 0.01 to 30 parts by weight.

The resin beads used as the component (B) of the present invention have an average particle size in the range of 10 to 200 μm and are composed of a polymer compound having a stable shape at the heat curing temperature of the component (A). It is a sphere. The shape of the resin beads is preferably a true spherical body, but may be a pseudo spherical body having a slightly deformed shape. A columnar body, a needle-shaped body, an amorphous body, or the like is not preferable because the dispersibility during the production of a coating material is reduced and the desired satin pattern is impaired.

The resin beads are preferably made of a resin having compatibility or compatibility with the thermosetting resin as the component (A). Further, from the viewpoint of preventing thermal deformation during heating, a thermoplastic resin or a thermosetting resin having a three-dimensional crosslinked structure is desirable, but if the shape is stable at the heat curing temperature of the component (A), it is highly non-crosslinkable. It may be a molecular compound. Further, the resin beads may contain various reactive functional groups, but it is preferable that the resin beads are inactive with respect to the reactive functional groups of the component (A).

These resin beads are not particularly limited in their resin composition, synthetic route, etc. as long as they have the above-mentioned average particle diameter and the above-mentioned shape, and nylon, polyolefin, acrylic resin, epoxy resin, polyester resin, urethane resin, Polymer compounds such as melamine resins, thermoplastic resins or three-dimensionally crosslinked thermoplastic resins or thermosetting resins can be preferably used. Further, as the resin beads, colored beads containing an organic pigment and / or an inorganic pigment can be used depending on the desired pattern tone.

As a method of producing these resin beads, for example, in the case of an acrylic resin, it can be produced by emulsion polymerization of an α, β-unsaturated monomer and a polyfunctional unsaturated monomer. Further, resin beads such as an epoxy resin can be produced by carrying out a solution polymerization, followed by a crosslinking reaction at the time of emulsification, and removing the solvent. Other resins can also be manufactured by known methods for manufacturing the respective resins.

Commercially available products can also be used as the resin beads.
Typical examples of commercially available resin beads include, for example, polyamide resin (nylon) such as Olgasol powder (trade name: Nippon Rilsan Co., Ltd.), Daiamide (trade name: Daicel Huls Co., Ltd.), and polyolefins such as miperone. XM (trade name: Mitsui Petrochemical Industry Co., Ltd.) and the like can be mentioned. Furthermore, examples of the acrylic resin include Julimer MB (trade name: Nippon Pure Chemicals Co., Ltd.), Tough AR (trade name: Toyobo Co., Ltd.),
Love Koror (trade name: Dainichi Seika Kogyo Co., Ltd.), Techpolymer MBX, Techpolymer SBX, Techpolymer S
Thermoplastic resins such as ME (trade name: Sekisui Plastics Co., Ltd.), Fine Pearl PB, Fine Pearl PM (trade name: Sumitomo Chemical Co., Ltd.), SPG type, SP type (trade name: Soken Chemical Co., Ltd.) Examples include beads.
Also, as the polyester resin, Varinax FC (trade name: Mitsui Toatsu Chemical Co., Ltd.), and as the urethane resin, Vernox CFB (trade name: Dainippon Ink and Chemicals Co., Ltd.), urethane beads (Sekisui Plastics Co., Ltd. product ), Decosilk (trade name: Sakai Shoji Co., Ltd.), and melamine resin, Eposter L (trade name: Nippon Shokubai Co., Ltd.), Bell Pearl R, Bell Pearl H, Bell Pearl C (trade name: Kanebo Co., Ltd.) and Univex-C, The thermosetting resin beads such as Univex-WA-C and GCP series (trade name: Unitika Ltd.) can be mentioned.

Regarding the use of these resin beads,
Only one type of arbitrary type may be used, or two or more types may be used in combination, depending on the desired pattern tone regardless of whether it is colored or colorless.

The average particle size of the resin beads used as the component (B) may be in the range of 10 to 200 μm, but is preferably in the range of 30 to 150 μm.
Here, if the average particle size exceeds 200 μm, the obtained pattern becomes rough and not only the uniformity and design of the obtained pattern are impaired but also the physical properties of the coating film deteriorate. The average particle size is 1
If it is less than 0 μm, it becomes difficult to form a pattern on the coating film,
In addition, a matting effect may occur, which is not preferable.

The particle size of the resin beads may be selected from those having an appropriate particle size depending on the desired pattern tone, and only one kind may be used.
Alternatively, two or more kinds may be used in combination. For example, when only resin beads having an average particle size of less than 50 μm are used, a satin pattern generally obtained tends to be shallow, but beads having an average particle size of less than 50 μm and an average particle size of 5 are used.
A good satin pattern can be obtained by using resin beads of 0 to 200 μm in combination.

The uneven pattern-forming powder coating material of the present invention is a thermosetting powder coating material of component (A) containing the above-mentioned thermosetting resin and pigments, modifiers and other additives optionally added. 60 to 99.9% by weight of the component, preferably 70 to 95% by weight, 0.1 to 40% by weight of the resin beads of the component (B),
It is preferably a powder coating material containing 5 to 30% by weight. A satin-like pattern can be obtained even if the content of the resin beads exceeds 40% by weight, but the physical properties of the coating film are deteriorated with respect to processability and corrosion resistance, and if it is less than 0.1% by weight, the coating has poor uniformity. It becomes a film.

In the powder coating material of the present invention, it is desirable that the resin beads of the component (B) are uniformly dispersed in the powder coating component of the component (A). In this case, the resin beads need to be uniformly dispersed in the component (A) while maintaining the spherical shape. In order to prevent the components (A) and (B) from separating during storage, transportation, and painting operations, it is important that both components are in a melted and integrated state.

In the method for producing a powder coating composition for forming a concavo-convex pattern according to the present invention, both components (A) and (B) are heated to a temperature at which the resin component in component (A) is melted, and component (B) is added. This is a method of dispersing it in the component (A). In this case, the softening temperature of the component (B) melts the resin component in the component (A) so that the resin component of the component (B) maintains the spherical shape at the temperature at which the resin component in the component (A) melts. Must be above temperature.

In the above-mentioned manufacturing method, the components (A) and (B) are simultaneously kneaded at the temperature at which the resin component in the component (A) is melted during the production of the powder coating material, and the powder coating material thus melted is mixed. The resin beads can be dispersed. This is not a special method, and the resin beads can be dispersed by kneading in accordance with the usual powder coating production.

Specifically, the powder coating material is manufactured by adding a predetermined amount of the component (B) to a mixture of the thermosetting resin main component, the pigment and the additive which is the component (A), and mixing them with a dry blender. Then, using an extrusion kneader, a single-screw or twin-screw extruder, and the like, melt-kneading is performed in a temperature range in which the resin component in the component (A) is melted, usually 80 to 120 ° C., and pelletized and then cooled. This is finely pulverized by an impact pulverizer, an air flow type pulverizer or the like, and classified to produce a powder coating material. The resin beads as the component (B) are required to have such strength that they are not deformed by heating and that they are not crushed when crushed.

If the component (B) is not dispersed in the component (A) and the component (B) is added and dispersed at the time of pulverization after the melt kneading of the component (A) or at the time of classification, the powder coating composition is obtained. Not only the content of component (B) in the product becomes unstable between production lots, but also the uniformity of the pattern is impaired due to the change in the coating efficiency during coating, and the pattern tone changes when the recovered powder is used. May cause the deterioration of the physical properties of the coating film such as workability and corrosion resistance due to non-uniformity of the formed pattern,
Not preferred.

The coating method using the irregularity pattern-forming powder coating material of the present invention is a conventional coating method for powder coating material such as electrostatic spraying method, fluidized bed immersion method or electrostatic fluidized bed coating method. By applying to an object to be coated with the above, and then heating and melting to cure, a coating film having a satin-like uneven pattern having a soft and high design is formed to obtain a coated object. in this case,
In order for the cured coating film formed by the component (A) to have a film thickness that does not exceed the average particle size of the resin beads of the component (B),
Select the powder coating composition and coating amount. Of the coating finishing methods, the electrostatic spraying method is particularly preferable.

The material and shape of the article to be coated are not particularly limited as long as it can withstand the heating conditions at the time of forming the coating film, and any article can be coated. As a material of such an object to be coated, for example, 0.2 to 2 mm
Examples include thick steel plates, galvanized steel plates, aluminum plates, metal plates such as stainless steel plates, glass, ceramics, and molded products thereof.

In order to apply the powder coating material to the above-mentioned object to be coated, a commercially available electrostatic coating machine (load voltage: -50 to-) is applied to the object to be coated.
(90 kV) or other powder coating method, and then uniformly heated and melted in a hot-air baking furnace, an infrared furnace, an induction heating furnace or the like to be cured to form a coating film. The conditions for heat curing depend on the type of the thermosetting powder coating composition (A) and the composition of the coating composition, but the temperature of the article to be coated is usually 150 to 280 ° C.
For 1 to 30 minutes, preferably 170 to 250 ° C. for 3 to
Twenty minutes is suitable.

The coating film thickness is usually 30 to 30 on average.
It is suitable to apply it to 150 μm, preferably 50 to 80 μm. At this time, if the film thickness is adjusted so as not to exceed the average particle diameter of the component (B) used, a coating film having uniform, dense and fine rounded protrusions is formed, and it is soft and has a satin tone of high design. An uneven pattern is obtained. Here, the average film thickness is the average value of the entire film thickness including the convex and concave portions, and is calculated arithmetically from the area of the object to be coated, the coating weight of the coating used for coating, and the specific gravity of the coating. You can

Regarding the uneven pattern formed as described above, if the range of the pattern is limited from the parameters of surface roughness and undulation according to "JIS B-0601 (1994) Definition and indication of surface roughness", the rounded protrusions are formed. The above parameters of surface roughness and waviness due to the pattern are preferably within the range of the following Table 1 at all 5 or more arbitrarily selected surface roughness measurement points on the coating film surface.

Here, the center line average roughness Ra, the average spacing Sm of the uneven portions, and the average spacing S of the local peaks are the density of the above-mentioned projection-like pattern, and the ten-point average roughness Rz is the height of the pattern. It is expressed and has the following values. Ra: average value of absolute value deviation from the average line. Rz: The sum of the average value of the absolute values of 5 points from the highest convex portion and the average value of the absolute values of 5 points from the lowest concave portion for each reference length. Sm: The average value of the intervals of one cycle of unevenness obtained from the intersection where the roughness curve intersects the average line. S: Average value of the interval between adjacent local convex portions.

[0031]

[Table 1]

The coating film formed as described above has a uniform, dense, finely rounded, projection-like pattern formed of resin beads, so that a satin-like uneven pattern having a soft and high design can be obtained. Since the powder coating component of component (A) and the resin beads of component (B) are integrated by welding, a coating film having excellent chemical performance, physical performance, particularly workability and corrosion resistance can be obtained. It is possible to visually observe whether or not the projections of the uneven pattern are rounded, but they can be visualized by drawing an enlarged three-dimensional sectional view.

When a crushed or amorphous resin granular material is used instead of the resin beads of the component (B), a coating film having angular projections is formed, and a coating film having a cold feeling and a bad texture is formed. Since the coating film peels off from the angular portion, a coating film with inferior chemical and physical properties can be obtained.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an enlarged view of a coated article in which a powder coating material composed of a powder coating material component (A) and resin beads of a component (B) is applied to form an uneven coating film.
Is a perspective view, and (b) is a sectional view.

In FIG. 1, a coated article 1 has an uneven coating film 3 formed on the surface of a coated article 2. In this uneven coating film 3, resin beads 5 of component (B) are embedded in a coating film 4 formed of component (A). A portion where the resin beads 5 do not exist is formed as a concave portion 6, and a portion where the resin beads 5 project is formed as a convex portion 7.

In this uneven coating film 3, since the spherical resin beads 5 are projected on the convex portion 7 and the coating film 4 is continuous in a skirt shape, the rounded convex portion 7 is formed, and the satin is soft and has high designability. An uneven coating film having a tone is obtained.

FIG. 2A is an enlarged perspective view showing a coated article using crushed resin particles 8 instead of the resin beads 5 of FIG. 1 as a comparative example, and FIG. 2B is a sectional view thereof. . In FIG. 2, since the convex portion 7 is formed by the crushed resin granular material 8, the convex portion 7 becomes an angular protrusion, a soft uneven pattern is not obtained, and a coating film having a cold feeling and a bad texture is obtained.

[0038]

EXAMPLES Next, the present invention will be described more specifically by way of examples, but the present invention is not limited to these examples.

In each example, physical properties such as coating film performance were determined as follows. (1) Specular gloss The values when the incident angle and the light receiving angle are 60 degrees are shown according to JIS K-5400 (1990) 7.6. (2) Pencil hardness The pencil hardness was determined according to JIS K-5400 (1990) 84.2 Hand-shaking method.

(3) Erichsen value It was measured according to JIS K-5400 (1990) 8.2.2 Breaking distance method. (4) Impact resistance The impact resistance was measured according to JIS K-5400 (1990) 8.3.2 DuPont type. (5) Flex resistance It was performed according to JIS K-5400 (1990) 8.1.

(6) Workability test A material piece is sandwiched between test pieces and a 180-degree bending test is performed using a vise. The number of material pieces that do not cause coating film defects such as cracks on the curved surface of the coating film is shown. In this case, for example, a passing value when two pieces of material are sandwiched is expressed as 2T.

(7) Salt Water Spray Resistance According to JIS K-5400 (1990) 9.1, the surface of the coating film was cross-cut and then continuously tested for 300 hours. In the peel test, peel the tape on the cut surface,
The maximum value of the width peeled from the cut center line was shown.

(8) Surface condition The condition was judged by the following criteria by visual observation. Normal: A state in which convex portions form independent protruding patterns. Slightly dense: A state in which a protruding pattern is formed by partially overlapping convex portions. Quite dense: A state in which most of the convex portions overlap to form a protruding pattern.

(9) Surface Roughness Measurement Surface roughness and undulation parameters were measured according to JIS B-0601 (1994) Definition of Surface Roughness and Display, and the range of pattern tone was expressed numerically. [Parameters related to amplitude] Ra: center line average roughness (μm), Rz: ten-point average roughness (μm) [Parameters related to wavelength] Sm: average interval of irregularities (mm), S: average interval of local peaks ( mm)

(10) Three-dimensional cross-sectional view The three-dimensional cross-sectional view is a three-dimensional surface roughness profile measuring device (trade name: Tokyo Seimitsu Co., Ltd., Surfcom E-RC-XY).
3B), a cross-sectional curve of the surface of the coating film that was not tilt-corrected was prepared by measuring the longitudinal magnification at 100 times, the lateral magnification, and the front-back magnification at 50 times, and the pitch at 20 μm.

(11) Evaluation of pattern tone Overall judgment was made according to the following criteria from the results of visual observation, three-dimensional sectional view and surface roughness measurement. Good: A design coating film having a uniform, dense and fine rounded protrusion pattern was formed, and the parameter due to the protrusion pattern was within the preferable range in Table 1 above. Bad: Other than the above.

Examples 1 to 3 The components of Examples 1 to 3 shown in Table 2 were uniformly mixed for about 1 minute with a dry blender (trade name: Henschel Mixer, manufactured by Mitsui Miike Kakoki Co., Ltd.), and then 80 to 1
Melt-kneading is performed using an extrusion kneader (trade name: Busco Kneader PR-46, manufactured by Buss Co., Ltd.) under a temperature condition of 00 ° C., and after cooling, finely pulverized by a hammer-type impact pulverizer and then classified by an 80-mesh wire net. To produce a powder coating. The obtained powder coating material was applied to an object to be coated having a predetermined plate thickness by an electrostatic spraying method with a charge of -80 kv so that the coating average film thickness shown in Table 3 was obtained. Then, after heat curing under the baking conditions shown in Table 3, the appearance of the coating film and the physical properties of the coating film were evaluated. The results are shown in Table 3 and FIGS.

[0048]

[Table 2]

Note 1 in Table 2) Trade name: DSM Resins product, polyester resin, acid value 35 mg KOH / g. 2) Trade name: Dainippon Ink and Chemicals, Inc. product, polyester resin, hydroxyl value 30 mgKOH / g. 3) Trade name: Shell Chemicals, epoxy resin, epoxy equivalent 650 g / Eq. 4) Trade name; product of Huels, isocyanate hardener for adduct, isocyanate equivalent weight 280 g / Eq. 5) Trade name: Monsant product, leveling agent. 6) Trade name: Estron Chemical, In
c. Company product, curing accelerator. 7) Product name: Toyobo Co., Ltd. product, true spherical acrylic beads, average particle size in parentheses.

[0050]

[Table 3]

Example 1 is a hybrid powder coating as the component (A), Example 2 is a hybrid powder coating using two kinds of resin beads having different average particle diameters, and Example 3 is a PCM.
It is a thermosetting powder coating material of the present invention using a urethane-based powder coating material for (Brecoat metal steel sheet). As is clear from Table 3 and FIGS. 3 to 5, the coating film coated with the above powder coating has a satin-like uniform uneven pattern formed on the article to be coated, A coating film having excellent chemical properties and physical properties as well as excellent design properties was obtained.

Comparative Examples 1 and 2 The components of Comparative Examples 1 and 2 shown in Table 4 were uniformly mixed for about 1 minute by a dry blender (trade name: Henschel mixer, manufactured by Mitsui Miike Kakoki Co., Ltd.), and then 80 to 1
Melt-kneading is performed using an extrusion kneader (trade name: Busco Kneader PR-46, manufactured by Buss Co., Ltd.) at a temperature of 00 ° C., and after cooling, finely pulverized with a hammer-type impact pulverizer, and then classified with a wire mesh of 80 mesh. To produce a powder coating. The obtained powder coating material should have the coating average film thickness shown in Table-5.
Coating was performed on an object to be coated having a predetermined plate thickness by electrostatic spraying with 80 kv charging. Then, after heating and curing under the baking conditions shown in Table 5, the appearance of the coating film and the physical properties of the coating film were evaluated. The results are shown in Table 5 and FIGS.

Comparative Examples 3 to 4 In Comparative Example 3, the components (A) shown in Table 4 were uniformly mixed for about 1 minute by a dry blender (trade name: Henschel mixer, manufactured by Mitsui Miike Kakoki Co., Ltd.), and then 80 to 10
Melt-kneading is performed using an extrusion kneader (trade name: Busco Kneader PR-46, manufactured by Buss Co., Ltd.) under a temperature condition of 0 ° C., and after cooling, the component (B) is added and finely pulverized with a hammer-type impact pulverizer. The powder coating was manufactured by classifying with a wire mesh of 80 mesh. In Comparative Example 4, melt kneading was performed in the same manner as in Comparative Example 3 described above, and after cooling, finely pulverized by a hammer impact crusher. Then, the powder coating was manufactured by adding the component (B) and then classifying with a wire mesh of 80 mesh. The obtained powder coating material was applied to an object to be coated having a predetermined plate thickness by an electrostatic spraying method with a charge of -80 kv so that the average coating film thickness shown in Table 5 was obtained. Then, after heating and curing under the baking conditions shown in Table 5, the appearance of the coating film and the physical properties of the coating film were evaluated.
The results are shown in Table 5 and FIGS.

[0054]

[Table 4]

[0055]

[Table 5]

Comparative Example 1 is a powder coating using an amorphous resin as the component (B). As shown in FIG. 6, the obtained coating film formed an irregular rectangular convex pattern due to the amorphous resin, and the desired rounded convex pattern was not obtained. In Comparative Example 2, the component (B) has an average particle size of 80 μm.
The powder coating containing the resin beads described in 1 above was applied to a thickness of 100 μm or more. As shown in FIG. 7, the obtained coating film did not have a sufficient convex pattern on the surface of the coating film and lacked in designability. On the other hand, in each of the paints obtained in Comparative Examples 3 and 4, spraying unevenness occurred during coating, no pattern was obtained, and deterioration of physical properties of the coating film was also recognized.

[0057]

EFFECTS OF THE INVENTION Since the powder coating material for forming a concavo-convex pattern of the present invention contains resin beads whose shape is stable at the heat curing temperature of the thermosetting resin in the powder coating composition, it is possible to obtain uniform, dense and fine roundness. It is possible to form a coating film having a satin-like concavo-convex pattern that is soft and has a high design, which is represented by a tinged projecting pattern.

In the method for producing a powder coating composition for forming a concavo-convex pattern of the present invention, the resin beads are dispersed by heating to the melting temperature of the resin in the powder coating component, so that the powder coating component and the resin beads are welded and integrated. It is possible to produce a powder coating that has been converted into a powder coating, and thereby a coating film having the above-mentioned unevenness pattern and excellent in chemical performance and physical performance, particularly workability and corrosion resistance can be formed.

In the coated article of the present invention, the powder coating material as described above is applied to the article to be coated to form a coating film having a film thickness not exceeding the average particle diameter of the resin beads. A coated article on which a coating film having a pattern is formed can be obtained.

[Brief description of drawings]

FIG. 1A is an enlarged perspective view of a surface of a coated article according to an embodiment, and FIG. 1B is a sectional view.

FIG. 2A is an enlarged perspective view of a surface of a coated article of a comparative example,
(B) is a sectional view.

FIG. 3 is a three-dimensional cross-sectional view of Example 1.

FIG. 4 is a three-dimensional cross-sectional view of Example 2.

FIG. 5 is a three-dimensional cross-sectional view of Example 3.

6 is a three-dimensional sectional view of Comparative Example 1. FIG.

7 is a three-dimensional sectional view of Comparative Example 2. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coated product 2 Coated product 3 Uneven coating film 4 Coating film 5 Resin beads 6 Recessed portion 7 Convex portion 8 Resin granular material

Claims (4)

[Claims] 1. A thermosetting powder coating composition containing 60% to 99.9% by weight of (A) a thermosetting resin which is solid at room temperature, and (B) an average particle size of 10 to 200 μm, and (A). Resin beads whose shape is stable at the heat curing temperature of the components.
An uneven pattern-forming powder coating material containing 1 to 40% by weight. 2. Resin beads comprising a polyamide resin, a polyolefin resin, an acrylic resin, an epoxy resin, a polyester resin, a polyurethane resin and a melamine resin, and a thermoplastic resin and a thermosetting resin obtained by three-dimensionally crosslinking these resins. The powder coating composition according to claim 1, which is at least one selected from the group consisting of: 3. (A) 60 to 99.9% by weight of a thermosetting powder coating material component containing a thermosetting resin which is solid at room temperature, and (B) an average particle size of 10 to 200 μm, and (A) Resin beads whose shape is stable at the heat curing temperature of the components.
1-40% by weight is heated to a temperature at which the resin component in the component (A) is melted to disperse the component (B) in the component (A). Manufacturing method. 4. The powder coating composition according to claim 1 or 2 is applied to an object to be coated, and a cured coating film of component (A) is formed so as to have a film thickness not exceeding the average particle diameter of component (B). Painted items.