JP4939022B2 - Method for producing powder coating - Google Patents

Description

  The present invention relates to a powder coating material and a manufacturing method thereof.

  In recent years, in the paint field, solvent removal has been desired in order to reduce the impact on the environment, and powder paint has attracted attention as a countermeasure. Powder paint has advantages such as not using a solvent and easy recovery of paint that has not adhered to the painted surface, but it is not suitable for small lot production due to the complexity of the manufacturing process compared to the solvent type. However, due to reasons such as a long period from receipt of an order to shipment and difficulty in color matching (color matching), the spread of the product has been delayed.

  The powder coating is generally composed mainly of a resin for forming a coating film having a volume average particle size of about 30 to 40 μm, and is applied and baked by a method such as electrostatic powder coating or fluidized immersion coating. Therefore, a smooth coating film cannot be formed as compared with the solvent-type paint, and the appearance of the coating film is inferior.

  Therefore, in order to improve the above drawbacks, Patent Document 1 below discloses a powder coating material having a volume average particle size of 20 to 50 μm and a particle size distribution standard deviation of 20 μm or less. It is said that a powder coating material that can be formed and has excellent transportability is obtained. Further, Patent Document 2 discloses a powder coating material having an average particle size of 5 to 15 μm, a 90% cumulative particle size of 15 to 25 μm, and a spherical particle shape, and improves fluidity even if the particle size is small. It is said that the workability of powder coating is improved and the smoothness of the coating film is improved.

  However, since the powder coating described in Patent Document 1 is melt-kneaded and cooled and solidified, the solid material obtained is pulverized and sieved to the desired particle size. Don't be. Also, in the case of the spherical powder coating described in Patent Document 2, the solid material obtained by melt-kneading and cooling and solidifying is pulverized, sieved, and then heat-treated to melt the powder coating surface into a spherical shape. There are only.

  As described above, since the powder coatings of Patent Documents 1 and 2 pulverize and screen the powder coating once manufactured, the portion outside the target particle size is wasted, and if the particle size is to be made uniform The higher the cost, the higher the cost. Of course, it can be recovered and reused. In this case, however, an extra step is required, so that it is not possible to deny the possibility of not only cost increase but also quality degradation.

  By the way, powder coating materials have been conventionally dry-blended with a powder resin, a curing agent and, if necessary, a color pigment using a mixer, then heated and melt-kneaded using a kneader such as a twin screw extruder, cooled and pulverized. However, the manufacturing method is complicated because it undergoes a manufacturing process such as dry blending and then heat melting and kneading, and there is a risk of thickening and gelling during heating and melting and kneading. In addition to the time and effort required to clean the kneader and the inability to produce a low-temperature curable paint, the addition of the color pigment is performed in the first step, so it is necessary to return to the first step in order to achieve subtle color matching. There is a problem. Furthermore, the production method is suitable for mass production because it can be continuously produced once the production conditions are determined, but is not suitable for producing various kinds of paints in a small amount.

  In addition, heat melt kneading may not be performed only with dry blend, but this is to break down these scaly pigments as much as possible in order to give the painted surface a brightness feeling using scaly mica or metal as the pigment. Only if you do not want to. However, with dry blend alone, the pigment only adheres to the surface of the powder resin, so it is uneven and easy to peel off, resulting in poor color reproducibility of the painted surface and the use of paint that did not adhere to the painted surface. It will also be difficult.

  In order to improve at least one of the disadvantages of these production methods, the following patents have been filed.

  In Patent Literature 3, at least one substance selected from a curing agent, a curing catalyst, and a colorant is embedded or fixed on the surface of the powder resin particles using an impact impact device having a special structure, and is fixed. A method for producing a thermosetting powder coating is disclosed. Patent Document 4 discloses a manufacturing method for obtaining a powder coating material of a desired color by a compounding process in which a pigment is bonded to the surface of resin particles that are mother particles.

  Each of these is characterized in that at least one substance selected from a curing agent, a curing catalyst and a colorant, or a pigment is embedded and fixed or bonded to the surface of resin particles produced in advance.

  However, the powder impact device described in Patent Document 3 has a rotating disk in which an impact pin is provided in the impact chamber, and is located along the outermost raceway surface of the impact pin and with a certain space with respect to it. Because it is complicated, such as having a circulation path arranged so as to be connected to the vicinity of the center of the rotating disk from a circulation opening opened in a part of the impact belt ring, after providing an impact chamber in which the impact belt ring is arranged, A great deal of effort is required to clean and maintain the device. In particular, when trying to produce a small amount of various types of powder coatings, it causes an increase in cost.

In addition, in the apparatus that combines the pigment described in Patent Document 4 with resin particles that are base particles, the pigment and resin particles that are to be processed are pressed against the receiving surface that rotates by centrifugal force, and the receiving surface and the pressing surface are pressed. It is said that it is combined and combined by receiving pressing force and shearing force with the head, but in order to efficiently mix and circulate the object to be processed, there is a device such as a hole provided at the bottom of the receiving surface It has been subjected. As a result, the apparatus has a complicated structure, which is disadvantageous for cleaning and maintenance.
JP-A-8-41384 JP-A-9-208855 JP-A-8-176468 JP 2003-119427 A

The present invention has been made in view of solving the above-mentioned problems, and even if the particle size is small, the fluidity is good, so that the workability is improved and a high-appearance coating film can be formed. In this case, it is a method for producing a powder paint that can achieve vivid colors even if there are few colorants such as pigments, and the powder paint is produced in a short time with a simple structure that is easy to clean and maintain. It aims to provide a way to do.

In order to solve the above problems, the invention according to claim 1 is a lower stage in which powder resin particles and at least one additive selected from a curing agent, a curing catalyst, and a colorant are rotated along the inner bottom surface of the container. A spherical mixer provided with two types of rotary blades, a rotary blade and an upper rotary blade rotating at the center of the container, is mixed and stirred at a tip peripheral speed of the spherical mixer of 20 m / sec or more. Volume average particle size is 10-30 μm
And a powder coating production method in which the standard deviation is 15 μm or less, the particle shape is spherical , and the additive is embedded or fixed on the surface of the powder resin particles .

The invention according to claim 2 is characterized in that the resin component of the powder resin particles is at least one selected from a polyester resin, an epoxy resin, an acrylic resin, and a hybrid resin thereof. Item 2. A method for producing a powder coating material according to Item 1 .

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the powder coating material which can form a high-appearance coating film, and the method of manufacturing the said powder coating material in a short time can be provided with the apparatus of a simple structure. That is, the powder coating material of the present invention is excellent in fluidity because it has a spherical shape with a uniform particle size even if the particle size is small, and it becomes a coating film having a high appearance when coated. In addition, according to the production method of the present invention, it is possible to achieve a significant productivity improvement of the powder coating material, thereby not only making it possible to break down the cost barrier that is preventing the spread of the powder coating material, but also a small variety of products. It can easily handle the production of powder coatings.

  Furthermore, in the case of colored powder paints colored with pigments, the pigment is buried and fixed only near the surface of the paint powder, so it has higher coloring power than conventional powder paints and has a vivid color coating. A film can be obtained. In addition, since high-speed mixing is performed at a tip peripheral speed of 20 m / sec or more, the powder coating particles are spheroidized and averaged while being pulverized and united by the rotating blades, the machine wall and the particles, and the collision and friction between the particles. As a result, the particle size distribution becomes narrow.

  The powder coating material and its manufacturing method according to this embodiment will be described. In addition, this embodiment is only one form for implementing this invention, and this invention is not limited by this embodiment.

  As a result of intensive research, the inventors of the present invention are powder coatings obtained by embedding or fixing at least one additive selected from a curing agent, a curing catalyst, and a colorant on the surface of powder resin particles, Spherical mixer developed by the present applicant while finding that a powder coating having an average particle size of 10 to 30 μm and a standard deviation of 15 μm or less and having a spherical particle shape can form a coating film with excellent fluidity and high appearance The present invention was completed by finding that the powder coating material can be efficiently produced by using.

In the powder coating produced by the present invention, at least one additive selected from a curing agent, a curing catalyst and a colorant is buried or fixed on the surface of the powder resin particles, so that these additives are added from the surface of the powder coating. Things will not come off. Since these additives are present only near the surface of the powder coating material, the amount of these additives can be reduced compared to the powder coating material by heat-melt kneading, and is less susceptible to thermal degradation due to heat-melting. Moreover, since these additives are not only adhered to the surface as in the case of dry blending, a non-uniform and poorly painted surface is not obtained.

  In the present invention, the powder coating is spherical. The spherical shape is preferably a true spherical shape, but any spherical shape may be used. When the particle shape of the powder coating is other than spherical, for example, when the thermosetting powder coating is mechanically pulverized by a pulverizer such as a jet mill, a pin disc mill, an atomizer, etc., the particle surface shape is irregular and angular. As a result, the fluidity of the powder coating is lowered, and as a result, the coating workability is lowered.

  The powder coating material of the present invention has a volume average particle size of 10 to 30 μm. If it is smaller than 10 μm, it is easy to agglomerate even if the particle size is uniform, and the fluidity is deteriorated, so that clogging with a transfer pipe or nozzle is likely to occur in the painting operation. On the other hand, when the thickness exceeds 30 μm, the coating film having a high appearance cannot be obtained as a result of the loss of smoothness.

  The particle diameter of the largest powder coating material of the present invention is 80 μm or less. If the thickness exceeds 80 μm, the additive is buried and fixed only on the surface of the paint, so that the coating is not sufficiently cured, and the interior of the paint comes out on the surface, resulting in uneven color.

The standard deviation is 15 μm or less. If it exceeds 15 μm, the particle size becomes uneven, so the fluidity is poor and the coating film does not have a high appearance. The standard deviation SD used in the present invention is generally used in statistics, and is defined by Equation 1 and is a measure of the particle size distribution. The smaller the value, the narrower the particle size distribution, that is, the more uniform the particle size.
SD = [Σ {(D−X) ² } / n] ^1/2 (Formula 1)
(In the formula, SD is the standard deviation of the particle size distribution, D is the particle size of each particle, X is the volume average particle size, and n is the number of data.)

  In the present invention, the data used for calculating the volume average particle diameter and standard deviation of powder resin particles, powder paint particles, etc. can be measured using a laser particle size distribution measuring instrument such as Nikkiso Microtrack. it can.

  The powder resin particles used in the present invention preferably have a softening point of 30 to 100 ° C, and more preferably in the range of 40 to 60 ° C. When the softening point is lower than 30 ° C., the powder resin particles are fused with each other at the time of manufacture, making it difficult to manufacture. On the other hand, when the softening point is higher than 100 ° C., the adhesion of the immobilizing substance is deteriorated and the appearance, performance, etc. There are drawbacks.

  The powder resin particles are particles whose main component is a resin, and the particles may contain one or more of a curing agent, a curing catalyst, and a colorant.

  As the resin that is the main component of the powder resin particles, the same resins as those used in general powder coatings can be used, and examples thereof include polyester, epoxy, acrylic, and hybrid resins thereof. These include thermoplastic resins and thermosetting resins. In electrostatic powder coating, thermosetting resins are often used. In addition, fluorine-based thermosetting or thermoplastic resins, polyethylene, polypropylene, nylon, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, thermoplastic resins such as vinyl chloride, melamine, polyurethane, etc. These thermosetting resins can also be used.

  The curing agent that may be contained in the powder resin particles is not particularly limited as long as it reacts with a functional group contained in the resin to form a cured coating film. For example, in a resin containing a hydroxyl group, an amino resin ( Hexamethoxymelamine resins, etc.), block polyisocyanates (caprolactam block isophorone diisocyanate, etc.) hardeners, carboxyl group-containing resins such as polyepoxides (triglycidyl isocyanate etc.), epoxy group-containing resins, polycarboxylic Examples of blocked isocyanate group-containing resins such as acids (dodecanedioic acid, trimellitic acid, adipic hydrazide, etc.) include curing agents such as polyol (trimethylolpropane, etc.).

  Examples of the curing catalyst that may be contained in the powder resin particles include an acid such as an organic acid (paratoluenesulfonic acid, dodecylbenzenesulfonic acid, etc.), an inorganic acid (phosphoric acid, etc.) in the reaction between a hydroxyl group and an amino resin. Catalysts: Organic tin catalysts (tetrabutyltin, dibutyldilauryltin, tetrabutyldiacetylstannoxane, etc.) for the reaction of hydroxyl groups with block polyisocyanate groups; acids (boron trifluoride, etc.) for the reaction of carboxyl groups and epoxy groups Bases (amines, alkaline earth metal hydroxides, etc.), salts (quaternary onium salts, etc.), organometallic catalysts (stannous chloride, tetrabutyl zirconate, etc.) and the like can be used. Epoxy group-containing resin curing catalysts can be obtained without using a curing agent, for example, there are polymerization catalysts such as benzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate. Can be used alone.

  Examples of the colorant that may be contained in the powder resin particles include organic pigments and inorganic pigments. Examples of organic pigments include azo pigments (such as fast yellow), phthalocyanine pigments (such as phthalocyanine blue and phthalocyanine green), condensed polycyclic pigments (such as quinacridone red and perylene red), and nitroso pigments (such as naphthol yellow). Examples of inorganic pigments include oxide pigments (titanium dioxide, dials, etc.), phthalocyanide pigments (bitumen, etc.), chromate pigments (molybdenum red, etc.), carbon pigments (carbon black, etc.) , Mica pigments (colored mica, etc.), metal powder pigments (scale-side aluminum powder, bronze powder, zinc dust, etc.). These pigments may be coated with a pigment dispersant.

  In order to contain a curing agent, a curing catalyst, and a colorant in the powder resin particles, generally, the powder resin particles are melted and kneaded, and then cooled and pulverized.

  In addition to the above-mentioned additives, the powder resin particles may contain a filler, a rust inhibitor, an ultraviolet stabilizer, an ultraviolet absorber, a fluidity modifier, a repellency inhibitor, etc., if necessary. It can be used in any state of powder or liquid (which may be dissolved or dispersed in water or an organic solvent).

  When the additive is used as a powder or dispersion, the average particle size is preferably in the range of 0.001 to 30 μm, more preferably in the range of 0.01 to 20 μm.

When the average particle diameter of the additive is below the above range, mechanical force is less likely to be applied, so the adhesion to the powder resin particle is reduced, and when the above range is exceeded, the contact area with the powder resin particle is reduced. It is not preferable because defects such as powder coating workability, coating film performance, and color unevenness appear.

  In addition, it is preferable to use an additive having a particle size smaller than that of the powder resin particles from the viewpoints of powder coating workability, coating finish, and coating performance.

  When manufacturing the powder coating material of this invention, an additive may be supplied simultaneously with powder resin particle | grains or separately, and these may be supplied after melt | fusion and / or mixing previously.

  Additives such as a curing agent, a curing catalyst, and a colorant are the same as those described above, but as the colorant, a colored powder coating can be used in addition to the above-described ones. Examples of the colored powder coating material include those obtained by blending a thermoplastic resin and / or a thermosetting resin with a colorant, and may contain a curing agent and / or a curing catalyst.

  The mixing ratio of the additive depends on the properties of the target powder coating, but is preferably within 50%, more preferably within 20% with respect to the total amount.

  In order to embed or fix the additive on the surface of the powder resin particles, a spherical mixer developed by the present applicant is used for mixing and stirring. The tip peripheral speed of the rotary blade of the spherical mixer is preferably 20 m / sec or more. If the speed is lower than this, a sufficient amount of force is not applied to the surface of the powder resin particles, so that a powder coating cannot be produced in a short time. The structure of the inner surface of the container of the spherical mixer includes not only a true sphere but also a substantially spherical one, such as an oval or a spherical container having an elliptical cross section. In addition, the stirring blade rotating in the container is provided with two types of rotating blades, a lower rotating blade rotating along the bottom surface of the container and an upper rotating blade rotating at the center, so that a powder coating with better quality can be obtained. Since it is obtained, it is preferable.

  As a typical example of the spherical mixer, a spherical mixer having two upper and lower rotating blades shown in FIG. 2 will be described. The spherical mixer has a sample inlet 1 and an outlet 2 and is spherical inside, and has a spherical container bottom. Are provided with a lower rotating blade 3 and an upper rotating blade 4 rotating at the center. And the sample which exists in the bottom face center part in a container is stirred strongly with the rotational force of the lower stage rotary blade 3, and is pushed up along a wall surface from a container bottom part to a peripheral part and from the downward direction to the upper part. Since the sample pushed up along the container wall surface is spherical, the sample falls on the upper rotating blade 4 rotating at the center, and is vigorously stirred and mixed.

  That is, when the tip peripheral speed of the lower rotary blade of the spherical mixer is increased to 20 m / sec or more, the present inventors efficiently embed and fix the additive on the surface of the powder coating material. It has been found that a coating film excellent in finish, mechanical and chemical performance can be obtained when painted without peeling off. When the peripheral speed of the rotating blades of the spherical mixer is increased, it is preferable to cool the container, the drive shaft and / or the rotating blades of the spherical mixer with a coolant such as water in order to suppress deterioration of characteristics due to generated frictional heat. .

  Further, in FIG. 2, when the drive shaft 5 of the rotary blade is formed in a conical shape extending from the vicinity of the upper rotating portion toward the bottom surface of the spherical container, the sample does not stay on the bottom surface portion in the spherical container, and is stirred efficiently and uniformly. Since it is processed, it is preferable.

  As described above, since the spherical mixer has a simple structure, cleaning and maintenance are easy, and the rotational force is efficiently applied to the surface of the powder resin particles and the additive, so that the processing time is shortened.

  As mentioned above, although the manufacturing method of the powder coating material of this invention was demonstrated using the spherical mixer which the present applicant developed, if the powder coating material of this invention is obtained, it will not be limited to this manufacturing method.

  The powder coating can be performed by a method known per se, for example, a coating method such as electrostatic powder coating, triboelectric powder coating, fluid immersion, or the like. In the case of a thermosetting powder coating, after the powder coating, a cured coating film is formed by baking.

  Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In addition, what is described as a part in an Example and a comparative example represents a weight part.

In this example, the powder coating and powder coating were evaluated by the following test methods.
<Electric powder coating workability>
An electrostatic coating machine (Labjet, manufactured by SAMES) was used, and the stable supply and discharge stability of the powder coating to the gun were evaluated according to the following criteria.
○ is uniform discharge of powder and excellent paint workability.
Δ indicates uneven powder discharge and poor coating workability.
X indicates that the powder discharge is extremely uneven and the coating workability is very poor.

<Preparation of paint performance test coating plate>
Electrostatic powder coating is applied to a zinc phosphate-treated steel sheet so that the dry film thickness is about 60 μm, and baking is performed at a predetermined temperature as a test piece. The coating film appearance, specular reflectance, curability and Workability was tested by the following method.

<Appearance of coating film>
The coating surface was visually observed and evaluated.
○ indicates that there is no abnormality such as smoothness, gloss, and uneven color.
Δ indicates abnormalities such as smoothness, gloss, and uneven color.
X indicates that abnormalities such as smoothness, gloss, and color unevenness are remarkably observed.

<Specular reflectance>
The 60 degree specular glossiness of JIS K-5600-4-7 was measured.

<Curing property>
The appearance after wiping 10 times back and forth while pressing the xylene-impregnated gauze with the fingertips was visually evaluated. ○ indicates that the surface has no abnormality and good curability, Δ indicates that the surface is slightly scratched and inferior in curability, and × indicates that the surface dissolves and the curability is extremely inferior.

<Erichsen test>
The Eriksen test was conducted based on JIS-Z-2247.

Example 1
Epoxy resin powder (trade name: ARALDITE 6014, manufactured by Asahi Ciba) was pulverized with a pin disc mill. 7 parts of adipic acid hydrazide (average particle diameter 1 μm) was mixed with 100 parts of this powder and charged into a spherical mixer. After processing for 3 minutes at a peripheral speed of the stirring and mixing blades of 80 m / sec, 0.2 parts of silica (trade name: Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) was added as a flow regulator for the powder coating, and the periphery of the stirring and mixing blades After processing at a speed of 40 m / sec for 1 minute, coarse particles were removed with 150 mesh to obtain a powder coating material.
FIG. 1A shows a scanning electron micrograph of the powder coating before the spherical mixer treatment and FIG. 1B after the spherical mixer treatment.

Example 2
A polyester resin powder (trade name: GV-126, manufactured by Nippon Iupika Co., Ltd.) was pulverized with a pin disc mill. 100 parts of this powder was mixed with 10 parts of blocked isocyanate (trade name: B1530, manufactured by Huls) and charged into a spherical mixer. After processing for 3 minutes at a peripheral speed of the stirring and mixing blades of 80 m / sec, 0.2 parts of silica (trade name: Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) was added as a flow regulator for the powder coating, and the periphery of the stirring and mixing blades After processing at a speed of 40 m / sec for 1 minute, coarse particles were removed with 150 mesh to obtain a powder coating material.

Example 3
Acrylic resin (trade name: PD-7210 manufactured by Mitsui Chemicals) was pulverized and classified with a jet mill to adjust the average particle size to about 15 μm. To 100 parts of this powder, 15 parts of dodecanedioic acid (trade name: DDA manufactured by Ube Industries) was mixed and charged into a spherical mixer. After processing for 3 minutes at a peripheral speed of the stirring and mixing blades of 80 m / sec, 0.2 parts of silica (trade name: Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) was added as a flow regulator for the powder coating, and the periphery of the stirring and mixing blades After processing at a speed of 40 m / sec for 1 minute, coarse particles were removed with 150 mesh to obtain a powder coating material.

Comparative Example 1
A powder paint by dry blending was obtained in the same manner except that the spherical mixer was changed to a Henschel mixer in Example 1.

Comparative Example 2
A powder paint by dry blending was obtained in the same manner except that the spherical mixer was changed to a Henschel mixer in Example 2.

Comparative Example 3
A powder paint by dry blending was obtained in the same manner except that the spherical mixer was changed to a Henschel mixer in Example 3.

  The evaluation results of the powder coating materials obtained in Examples 1 to 3 and Comparative Examples 1 to 3 are summarized in Table 1, but the powder coating materials manufactured in Examples 1 to 3 according to the present invention are Comparative Example 1. Compared to the dry blends of ~ 3, it has excellent electrostatic coating workability, coating film appearance and curability, a firm coating film is formed from the results of the Eriksen test, and has a high specular reflectance. It can be seen that the coating surface is smooth and has a high appearance.

  In addition, from the scanning electron micrographs before (FIG. 1A) and after processing (FIG. 1B) in the spherical mixer in Example 1, when the spherical mixer processing is performed, the particle size is uniform and the particles are spherical without any angularity. Can be visually confirmed.

  In the following Examples 4 to 8 and Comparative Examples 4 to 8, the particle diameter, the angle of repose, and the visual characteristics (lightness, a value, b value, saturation) of the coating film were measured by the methods shown below.

<Particle size>
The particle size distribution and average particle size of the powder coating were measured using a laser type particle size distribution analyzer (Microtrac Nikkiso Co., Ltd.).

<Repose angle>
Using a powder tester (manufactured by Hosokawa Micron Corporation), the powder coating material was allowed to flow down on the table, and the angle of the ridgeline of the piles was measured.

<Visual characteristics of coating film>
The coating film was measured using a Macbeth CE7000 color difference meter based on JIS K 5600-4-5, and displayed according to JIS Z 8729.
1) Lightness (L value): A numerical value of color brightness. The closer to white, the higher, and the closer to black, the lower the value.
2) a value: A numerical value of redness. The higher the positive value, the closer to red, and the higher the negative value, the closer to green.
3) b value: A numerical value of yellowness. The higher the positive value, the closer to yellow, and the higher the negative value, the closer to blue.
4) Saturation: Quantification of color vividness. The bigger it is, the brighter it becomes.

Example 4
58 parts of epoxy resin powder (trade name: ARALDITE 6003 manufactured by Asahi Ciba Co., Ltd.), 42 parts of polyester resin powder (trade name: GV-230, manufactured by Nippon Yupica Co., Ltd.), curing catalyst (trade name: C11Z, manufactured by Shikoku Kasei Kogyo Co., Ltd.) 2 parts, 30 parts of titanium dioxide (trade name: CR-95, manufactured by Ishihara Sangyo Co., Ltd.), 0.8 parts of flow regulator (BASF product name: Acronal 4F), pinhole inhibitor (trade name, manufactured by Midori Chemical Co., Ltd.) 0.3 parts of benzoin) was weighed, dry blended with a Henschel mixer, melt kneaded at 120 ° C. using a twin screw extruder, and pulverized with a pin disk mill to produce a white powder paint.
100 parts of this white powder coating material was mixed with 1 part of copper phthalocyanine blue (trade name: FBK # 3, manufactured by Sanyo Dye Co., Ltd.) and charged into a spherical mixer. After processing for 5 minutes at a peripheral speed of the stirring and mixing blades of 40 m / sec, 0.2 part of silica (trade name: Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) was added and the peripheral speed of the stirring and mixing blades was 40 m / sec for 1 minute. After the treatment, coarse particles were removed with 150 mesh to obtain a blue powder paint.

Example 5
100 parts of white powder coating material produced in Example 4 1.7 parts of petal (Bayferx brand name: Biferox 120NM), 2.5 parts of titanium dioxide (Ishihara Sangyo brand name: CR-95) Were mixed and put into a spherical mixer. After processing for 5 minutes at a peripheral speed of the stirring and mixing blades of 80 m / sec, 0.2 part of silica (trade name: Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) is added and the peripheral speed of the stirring and mixing blades is 40 m / sec for 1 minute. After the treatment, coarse particles were removed with 150 mesh to obtain a brown powder paint.

Example 6
8 parts of a matting agent (trade name: VESTAGON B-68, manufactured by Huls) were mixed with 100 parts of the white powder coating material produced in Example 4, and charged into a spherical mixer. After processing for 4 minutes at a peripheral speed of the stirring and mixing blades of 120 m / sec, 0.2 part of silica (trade name: Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) is added and the peripheral speed of the stirring and mixing blades is 40 m / sec for 1 minute. After the treatment, coarse particles were removed with 150 mesh to obtain a matte white powder paint.

Example 7
59 parts of polyester resin powder (trade name: GV-126, manufactured by Nippon Iupika Co., Ltd.), 11 parts of blocked isocyanate (trade name: B1530, manufactured by Huls), 30 parts of titanium dioxide (trade name: CR-95, manufactured by Ishihara Sangyo Co., Ltd.) Weighing 0.8 parts of flow control agent (BASF brand name: acronal 4F) and 0.3 part of pinhole inhibitor (brand name: benzoin, manufactured by Midori Chemical Co., Ltd.), dry blending with a Henschel mixer, twin screw extruder Was melt kneaded at 120 ° C. and pulverized with a pin disc mill to produce a white powder coating material.
One part of copper phthalocyanine blue (trade name: FBK # 3, manufactured by Sanyo Dyeing Co., Ltd.) was mixed with 100 parts of this white powder coating material and charged into a spherical mixer. After processing for 5 minutes at a peripheral speed of the stirring and mixing blades of 40 m / sec, 0.2 part of silica (trade name: Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) was added and the peripheral speed of the stirring and mixing blades was 40 m / sec for 1 minute. After the treatment, coarse particles were removed with 150 mesh to obtain a blue powder paint.

Example 8
61 parts acrylic resin (trade name: PD-7210, manufactured by Mitsui Chemicals), 9 parts, dodecanedioic acid (trade name: DDA, manufactured by Ube Industries), 30 parts, titanium dioxide (trade name: CR-95, manufactured by Ishihara Sangyo Co., Ltd.) 0.6 parts of flow control agent (trade name: Resimix RL-4, manufactured by Mitsui Chemicals) is weighed, dry blended with a Henschel mixer, melt kneaded at 120 ° C using a twin screw extruder, and pulverized with a jet mill.・ Classification produced white powder paint.
One part of copper phthalocyanine blue (trade name: FBK # 3, manufactured by Sanyo Dyeing Co., Ltd.) was mixed with 100 parts of this white powder coating material and charged into a spherical mixer. After processing for 3 minutes at a peripheral speed of stirring and mixing blades of 120 m / sec, 0.4 part of silica (trade name: Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) was added, and the peripheral speed of stirring and mixing blades was 40 m / sec for 1 minute. After the treatment, coarse particles were removed with 150 mesh to obtain a blue powder paint.

Comparative Example 4-1
A powder paint by dry blending was obtained in the same manner except that the spherical mixer was changed to a Henschel mixer in Example 4.

Comparative Example 4-2
A compound obtained by removing silica (trade name: Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) from the total composition of Example 4 was mixed with a Henschel mixer, and then melt-kneaded at 120 ° C. using a twin-screw extruder, and then a pin disk. After pulverizing with a mill, 0.2 part of silica (Nippon Aerosil brand name: Aerosil R-972) was added and mixed for 1 minute, and then coarse particles were removed with 150 mesh to obtain a powder coating material by melt kneading and pulverization.

Comparative Example 4-3
0.8 parts of copper phthalocyanine blue (trade name: FBK # 3, manufactured by Sanyo Dye Co., Ltd.) was added to the composition obtained by removing silica (trade name: Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) from the total composition of Example 4. After mixing with a Henschel mixer, it was melt-kneaded at 120 ° C. using a twin screw extruder, pulverized with a pin disc mill, and 0.2 part of silica (Nippon Aerosil product name: Aerosil R-972) was added and mixed for 1 minute. Thereafter, coarse particles were removed with 150 mesh to obtain a powder coating material by melt kneading and pulverization.

Comparative Example 5-1
A powder paint by dry blending was obtained in the same manner except that the spherical mixer was changed to a Henschel mixer in Example 5.

Comparative Example 5-2
A compound obtained by removing silica (trade name: Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) from the total composition of Example 5 was mixed with a Henschel mixer, and then melt-kneaded at 120 ° C. using a twin-screw extruder, and then a pin disk. After pulverizing with a mill, 0.2 part of silica (Nippon Aerosil brand name: Aerosil R-972) was added and mixed for 1 minute, and then coarse particles were removed with 150 mesh to obtain a powder coating material by melt kneading and pulverization.

Comparative Example 6-1
A powder paint by dry blending was obtained in the same manner except that the spherical mixer was changed to a Henschel mixer in Example 6.

Comparative Example 6-2
A compound obtained by removing silica (trade name: Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) from the total composition of Example 6 was mixed with a Henschel mixer, and then melt-kneaded at 120 ° C. using a twin-screw extruder, and then a pin disk. After pulverizing with a mill, 0.2 part of silica (Nippon Aerosil brand name: Aerosil R-972) was added and mixed for 1 minute, and then coarse particles were removed with 150 mesh to obtain a powder coating material by melt kneading and pulverization.

Comparative Example 7-1
A powder paint by dry blending was obtained in the same manner except that the spherical mixer was changed to a Henschel mixer in Example 7.

Comparative Example 7-2
A compound obtained by removing silica (trade name: Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) from the total composition of Example 7 was mixed with a Henschel mixer, and then melt-kneaded at 120 ° C. using a twin-screw extruder, and a pin disk. After pulverizing with a mill, 0.2 part of silica (Nippon Aerosil brand name: Aerosil R-972) was added and mixed for 1 minute, and then coarse particles were removed with 150 mesh to obtain a powder coating material by melt kneading and pulverization.

Comparative Example 8-1
A powder paint by dry blending was obtained in the same manner except that the spherical mixer was changed to a Henschel mixer in Example 8.

Comparative Example 8-2
A blend obtained by removing silica (trade name: Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) from the entire blend composition of Example 8 was mixed with a Henschel mixer, melt-kneaded at 120 ° C. using a twin screw extruder, and jet mill After pulverization and classification, 0.4 part of silica (Nippon Aerosil product name: Aerosil R-972) was added and mixed for 1 minute, and then coarse particles were removed with 150 mesh to obtain a powder coating material by melt kneading and pulverization.

  Table 2 shows Examples 4 to 8, Table 3 shows Comparative Examples 4 and 5, and Table 4 shows Comparative Examples 6 to 8. The blue powder coating material of Example 4 has substantially the same particle size as the dry blend of Comparative Example 4-1, which has the same blending composition, but the standard deviation is small, and there is no coating workability and no color unevenness. It can be seen that the paint appearance is excellent and the colors become vivid. Moreover, although the coating external appearance is equivalent compared with the powder coating material by the melt-kneading grinding | pulverization of the comparative example 4-2 with the same compounding composition, since the angle of repose is small, fluidity | liquidity is good and it becomes a vivid color. In the conventional powder coating by melt kneading and pulverization (Comparative Example 4-3), even when 1.8 times the pigment is added, the saturation equivalent to that in Example 4 is not reached.

  The brown powder coating of Example 5 has a particle appearance that is almost the same as that of the dry blend of Comparative Example 5-1, but has a small standard deviation, excellent coating workability and no color unevenness, and vivid colors. Thus, even if compared with the powder coating material by melt kneading and pulverization of Comparative Example 5-2, the fluidity is good and the color is vivid.

  Example 6 is a formulation to which a matting agent is added, but it is excellent in coating workability and coating appearance as compared with the dry blend (Comparative Example 6-1), and it is understood that the effect of the matting agent is sufficiently exhibited. . Even when compared with the melt-kneaded and pulverized powder coating (Comparative Example 6-2), the effect of the matting agent is sufficiently exhibited.

  Examples 7 and 8 are blue powder coating materials in which the resin components are changed from those in Example 4. Compared to dry blends (Comparative Examples 7-1 and 8-1), the powder coating (Comparative Example 7) has excellent coating appearance such as no coating workability and no color unevenness, has a vivid color, is melt kneaded and pulverized. -2 and 8-2), the fluidity is good and the color is vivid.

  According to the present invention, even if the particle size is small, the fluidity is good, so that the workability is improved and a high-appearance coating film can be formed. It is possible to provide a powder coating material capable of realizing colors and a method of manufacturing the powder coating material in a short time with an apparatus having a simple structure that can be easily cleaned and maintained.

It is a scanning electron micrograph before the spherical mixer process of the powder coating material which concerns on this embodiment. It is a scanning electron micrograph after the spherical mixer process of the powder coating material which concerns on this embodiment. It is a manufacturing apparatus concerning this embodiment.

Claims (2)

Powder resin particles and at least one additive selected from a curing agent, a curing catalyst and a colorant,
Using a spherical mixer provided with two types of rotating blades, a lower rotating blade rotating along the bottom surface of the container and an upper rotating blade rotating at the center of the container,
Mixing and stirring at a tip peripheral speed of the rotary blade of the spherical mixer of 20 m / sec or more, the volume average particle diameter is 10 to 30 μm, the standard deviation is 15 μm or less, the particle shape is spherical , and the additive is A method for producing a powder coating, which is buried or fixed on the surface of powder resin particles .   The method for producing a powder coating material according to claim 1, wherein the resin component of the powder resin particles is at least one selected from a polyester resin, an epoxy resin, an acrylic resin, and a hybrid resin thereof.

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