JP3308490B2 - Toning method of powder coating and toning system for implementing the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toning method for toning by blending powder paints of a plurality of colors, and a toning system for implementing the method.

[0002]

2. Description of the Related Art In recent years, powder coatings which have high safety because they are coated with air as a medium without using a solvent and which have little influence on the environment have become widespread in the field of household appliances and the like. In general, a powder coating is produced by blending a colorant and other additives into a binder resin that forms a powder, melt-kneading, pulverizing and classifying.

[0003] A powder coating charged to a certain polarity by, for example, friction or corona discharge is electrostatically attached to the surface of a grounded object, and then heated and melted.
Alternatively, a preheated object to be coated is inserted into a powder coating suspended or fluidized in an air stream, and the powder coating is melted and spread on the surface of the coating using the preheating. By doing so, a continuous coating film is formed on the surface of the object to be coated.

[0004]

However, powder coatings are
Although it is becoming widespread in the so-called large lot painting field, which consumes a large amount of the same color paint, such as the home appliances mentioned above, the small lot painting field where multicolor paint is required little by little, Alternatively, in the field of painting or the like where fine adjustment of color is required after toning, the penetration rate is low, and at present it does not reach the level of conventional solvent-based paints.

[0005] One of the causes is that the conventional method for producing a powder coating is not suitable for small-lot production, and the tint cannot be easily adjusted as in the conventional solvent-based coating. That is, the conventional powder coating is prepared by adding a coloring agent that is toned to the target color to the binder resin that forms the powder, so that the color is previously adjusted to the predetermined color. Manufactured in.

For this reason, the conventional powder coating is suitable for coating a large lot in which a large amount of the same color paint is required. It is not suitable because the toning, as it were, is not so small, and the color cannot be easily adjusted. Therefore, in order to solve such problems and to be able to easily cope with small lot painting and color adjustment,
For example cyan (C), magenta (M), yellow (Y), preparation of a plurality of colors which are previously toned like three primary so-called color, a light-transmitting property of the powder coating, in accordance with the color of interest In addition, it has been studied to dry-blend using a mixing device such as a rotary blade type mixer and tones a powder coating having a predetermined color by mixing colors.

[0007] However, at present, it is necessary to rely on the knowledge, experience, and intuition of the worker to perform the above-described toning method. Variations in toning results may occur due to factors or external factors such as the type of colors to be toned (for example, very light colors) and the environmental conditions at work (season, weather, time, light conditions, etc.). Was.

It is an object of the present invention to provide a new method of toning a powder coating material which does not cause a variation in the toning result due to an internal or external factor affecting a worker during the toning operation, and a method for toning the same. And a toning system for implementing the above.

[0009]

In order to solve the above-mentioned problems, a method for toning a powder coating according to the present invention is directed to a method for preparing a plurality of colors of a light-transmitting material.
Is a toning method in which the powder paint is blended at a predetermined ratio, and the blend is performed by dry blending, wherein a light absorption coefficient K and a light absorption coefficient K are obtained from a wavelength-reflectance curve created by measuring a target color. Calculate the K / S value, which is the ratio to the scattering coefficient S. Then, calculate the K / S value and the translucency of a plurality of colors to be used in advance.
For the powder coating, a plurality of coating with Chigae color density, respectively
Isomeric matching is performed using the calculated reflectance calculated from the K / S values [(K / S) ₁ to (K / S) _n ] of n pieces of basic data obtained by forming a film and measuring the color. After performing a metameric match using the result of the isometric match and the tristimulus value calculated from the calculated reflectance, calculating the blending ratio of the powder paint of each color, based on the calculation result, The powder paint of each color is measured and dry blended.

The toning system of the present invention is for implementing the above-described toning method of the present invention. (A) A colorimetric system for measuring a target color to create a wavelength-reflectance curve. And (b) calculating a K / S value, which is a ratio between the light absorption coefficient K and the scattering coefficient S, from the wavelength-reflectance curve, and calculating the K / S value and a plurality of colors to be used in advance. For the translucent powder coating , several coatings with different color densities were formed.
K / S values of the n basic data obtained by measuring Te [(K / S) ₁
~ (K / S) _n ], an isometric match is performed using the calculated reflectance, and a metameric match is performed using the result of the isometric match and the tristimulus value calculated from the calculated reflectance. (C) a mixing device for dry blending a plurality of translucent powder paints, and (d) a calculation device for calculating the blending ratio of the powder coatings of each color. And a metering device for metering a predetermined amount of the powder paint based on the metering device and supplying the metered amount to the mixing device.

[0011] According to the present invention, the colorimetric data of the target color and the basic data of the powder paint of a plurality of colors to be used for the toning are subjected to an arithmetic operation in accordance with a fixed calculation formula to obtain each color. Calculates the mixing ratio of the powder paints, and based on it, weighs and mixes the powder paints of each color. Any effect on the color result can be eliminated. For this reason, according to the present invention, it is possible to always obtain a constant toning result, and it is possible to always toning the powder paint accurately.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below. As shown in FIG. 3, for example, as shown in FIG. 3, a toning system for implementing the toning method of the present invention includes a colorimetric device 1 that creates a wavelength-reflectance curve by measuring a target color, and such a colorimetric device. A K / S value, which is a ratio of a light absorption coefficient K and a scattering coefficient S, is calculated from the data of the wavelength-reflectance curve created by the apparatus 1, and the K / S value and a plurality of colors to be used in advance are calculated. A plurality of coatings with different color densities for translucent powder coatings
Are formed and the K / S values of the n pieces of basic data [(K
/ S) ₁ to (K / S) _n ], and isomeric matching is performed using the calculated reflectance. Then, the result of the isomeric matching and 3 calculated from the calculated reflectance described above.
An arithmetic unit 2 that performs a metameric match using the stimulus value to calculate the compounding ratio of the powder coating of each color, and a predetermined amount of the powder coating based on the calculation result by the arithmetic unit 2 is measured and mixed. The apparatus includes a measuring device 3 for supplying to the device 4 and a mixing device 4 for dry-blending the supplied powder coating materials of a plurality of colors.

In FIG. 1, reference numeral 5 denotes a storage device for recording, for example, the calculated reflectance calculated from the basic data of the powder paint of a plurality of colors to be used. The colorimeter 1 used in the above system includes, for example, a colorimeter and the like.
The storage device 5 includes, for example, a personal computer and an internal or external storage device. The mixing device 4 includes, for example, a rotary blade type mixer.

In the toning method of the present invention using such a system, as shown in FIG. 1, first, a color sample or the like of a target color to be toned is measured using the colorimeter 1, and A wavelength-reflectance curve is created [Steps S1 and S2]. Next, the data of the wavelength-reflectance curve is inputted to the arithmetic unit 2, and the arithmetic operation by the arithmetic unit 2
Based on Kubelka-Munk's law, the K / S value of the target color, which is the ratio between the light absorption coefficient K and the scattering coefficient S, at wavelengths at regular intervals (for example, every 20 nm) is calculated [ Step S3] Next, the K / S value and the color density of each of the powder paints of a plurality of colors to be used are different in advance as shown in FIG.
And K / S values of a plurality of basic data 1~n obtained by measuring a plurality of coating film formed colorimetric device 1 _{[(K / S) 1 ~ (} K /
S) _n ] and the calculated reflectance (the K / S value and the calculated reflectance may also be calculated using the arithmetic unit 2) and recorded in the storage device 5 to perform isometric matching. To match the spectral reflectance curves [Step S
4] Further, by performing a metameric match using the result of the isometric match and the tristimulus value calculated from the calculated reflectance to match the tristimulus values, the compounding ratio of the powder coating of each color can be adjusted. It is calculated [Step S5].

Next, based on the calculation result, the powder paint of each color is measured using the measuring device 3 (Step S6),
Dry blending by supplying to the mixing device 4 [Step S
7]. And then, dry blended powder paint,
After test coating under the same conditions as actual coating [Step S
8], colorimetry is performed using the colorimeter 1, the colorimetric data is input again to the arithmetic unit 2, and the arithmetic unit 2 compares the colorimetric data with the colorimetric data of the target color measured first. Then, it is determined whether there is a color shift (step S9).

If there is any deviation in the color in this determination, the arithmetic unit 2 corrects and calculates the mixing ratio of the powder coating material of each color based on the two colorimetric data (step S10). Steps S6 to S6 are again performed based on the result.
Repeat step 9. Then, in the determination of step S9, when the color shift between the coating film and the target color is eliminated, the toning of the powder paint is completed.

As a criterion for determining the presence or absence of a color shift in step S9, for example, a color difference ΔΕ ^* between the colorimetric data of the target color and the colorimetric data of the coating film is used. Specifically, for example, a color difference ΔΕ ^* between the colorimetric data of the target color and the colorimetric data of the coating film is a color difference Δ 以下^{* that} is equal to or less than a predetermined threshold value, without any color shift, and a color difference value exceeding the threshold value. The arithmetic unit 2 determines that there is a color shift.
Can be programmed. The threshold value is not limited to this, but is preferably about ΔΕ ^* = 0.8.

Step S7 of the above toning method
If the dry blending process is insufficient in the dry blending process, the aggregates of the powder coating for each color are not sufficiently disintegrated. On the contrary, in this case, the granularity of the coating film becomes so large as to be visible due to the aggregation of the powder coating, which may cause defects such as color segregation, mottle, and shading. There is.

Therefore, it is necessary to set an optimum time for the dry blending, and the above-described color difference ΔΕ ^* is suitably adopted as a setting standard. That is, (i) a powder paint sample to be used for toning is dry-blended using the mixing device 4 in advance prior to toning, and the hue in the powder state of the sample in the middle is measured. The color is measured at regular intervals using the color device 1, and it is necessary for the color difference ΔΕ ^* between the latest color measurement value and the previous color measurement value to be equal to or less than a threshold value (preferably 0.8 or less). Measured the dry blending time, and based on the data, set the dry blending time of the actual powder coating, or (ii)
The actual powder coating in the middle of dry blending is sampled at regular intervals using the mixing device 4 and the hue in the powder state is measured using the colorimeter 1 to obtain the latest colorimetric values. By terminating the dry blending when the color difference ΔΕ ^* between the colorimetric value and the previous colorimetric value becomes equal to or less than the threshold value (preferably 0.8 or less), defects such as color segregation, mottle, and shading are reduced. It is possible to produce a powder coating that is dry-blended without any risk of occurrence.

The toning method of the present invention described above uses, for example, magenta (M) to reproduce three colors of cyan (C), magenta (M), and yellow (Y), and particularly orange. C, M, Y in which three colors of cyan (C), red (R), and yellow (Y) to which red (R) is added in place of, or colorless and transparent (clear, T) are further added to these three colors. , T or four colors of C, R, Y, and T, or light cyan (LC) and the like in order to reproduce color gradations more finely and to eliminate graininess in the coating film. Light Magenta (LM) 2
C, LC, M, LM, Y, T with the addition of two colors, light cyan (LC) and light red (LR)
Particularly suitable for toning when performing a powder coating method using a translucent powder coating of a plurality of colors that have been previously toned to six colors such as C, LC, R, LR, Y, and T. Adopted to.

The components constituting the powder coating of the plurality of colors used in the toning method of the present invention include, but are not limited to, the following materials. (Binder Resin) As the binder resin, among various conventionally known resins used in powder coatings, in order to impart light transmission to the powder coating, the resin is excellent in light transmission and is applied to an object to be coated. Any of various resins that can be melted by heating at the time of application or after application to form a continuous coating film can be used.

Examples of the binder resin include, but are not limited to, polystyrene, chloropolystyrene,
Poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-
Butadiene copolymer, styrene-vinyl chloride copolymer,
Styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylate copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer Copolymer, styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.), styrene-methacrylic ester copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene Butyl methacrylate copolymer, styrene-phenyl methacrylate copolymer), styrene-α
Styrene resins (homopolymers or copolymers containing styrene or styrene substituents) such as methyl chloroacrylate copolymer, styrene-acrylonitrile-acrylate copolymer, acrylic acid, methyl acrylate, acrylic acid Acrylic resins [(meth) acrylic acid such as ethyl, butyl acrylate, octyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, phenyl methacrylate, and methyl α-chloroacrylate And a homopolymer or copolymer mainly composed of an ester thereof),
Polyvinyl chloride, low molecular weight polyethylene, low molecular weight polypropylene, ethylene-ethyl acrylate copolymer, polyvinyl butyral, ethylene-vinyl acetate copolymer,
Examples thereof include a polyester resin, an epoxy resin, and a silicone resin. These may be used alone or as a mixture of two or more.

Among the above, particularly preferred binder resins include styrene resins, acrylic resins and polyester resins. Among them, (i)
(1):

[0024]

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Wherein R ¹ and R ² are the same or different, lower alkylene groups. x and y are the same or different and each represent 0 or an integer of 1 or more;
7 A diol component represented by: (ii) a dicarboxylic acid, an acid anhydride or a lower alkyl ester thereof,
(iii) Trihydric or higher polycarboxylic acid, its anhydride or lower alkyl ester, or copolycondensation with trihydric or higher polyhydric alcohol, and has a hydroxyl value (OHV) based on its acid value (AV). ) Ratio OHV / AV value is 1.
Two or more polyester resins are preferred binder resins.

In the above polyester resin, lower alkylene groups corresponding to R ¹ and R ² in the general formula (1) include, for example, methylene, ethylene, trimethylene, propylene, tetramethylene, ethylethylene, pentamethylene, hexamethylene. Examples thereof include an alkylene group having 1 to 6 carbon atoms such as methylene. X + y in the general formula (1) is 1 to 7 as described above, and preferably 3 to 5. x
When + y exceeds 7, there is a problem that the molecular weight of the diol component becomes too large and the light transmittance of the coating film is reduced.

As the diol component represented by the general formula (1), for example, polyoxypropylene (2.2) -2,2
-Bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0)
-2,2-bis (4-hydroxyphenyl) propane,
Polyoxypropylene (2) -polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6.0) -2,2-bis (4-hydroxyphenyl) propane, etc. can give.

Examples of the dicarboxylic acids include oxalic acid, malonic acid, succinic acid, itaconic acid, glutaconic acid,
Examples include adipic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, azelaic acid, sebacic acid, cyclohexanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid and the like. These dicarboxylic acids may be esters with acid anhydrides or lower alkyls. Examples of the lower alkyl include an alkyl group having 1 to 6 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, s-butyl, t-butyl, n-pentyl, and n-hexyl. can give.

The polyhydric carboxylic acid having a valency of 3 or more, its anhydride or lower alkyl ester, and the polyhydric alcohol having a valency of 3 or more are used to adjust the acid value and the hydroxyl value of the polyester resin, It is blended for the purpose of. Examples of the trivalent or higher polycarboxylic acid, its acid anhydride or lower alkyl ester include trimellitic acid, 2,5,7-naphthalene tricarboxylic acid, 1,2,4-naphthalene tricarboxylic acid, 1,2,4- Butanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methoxycarbonylpropane, tetra (methoxycarbonyl) methane, 1,2,2
7,8-octanetetracarboxylic acid and the like.

Examples of the trihydric or higher polyhydric alcohol include glycerin, 2-methyl-1,2,3-propanetriol, 1,2,4-butanetriol and 2-methyl-1,2,4-butanetriol. , 1,2,5-pentatriol, pentaerythritol, dipentaerythritol, tripentaerythritol, hexitol, sorbitol, 1,4-sorbitan, 1,2,4-benzenetriol and the like.

The polyester resin is synthesized by copolycondensation of the above-mentioned components at a temperature of 180 to 250 ° C., for example, in an inert gas atmosphere. Acid value of polyester resin (A
The ratio of the hydroxyl value (OHV) to V) OHV / AV is 1.2 or more, preferably 1.2 to 50, more preferably 2 to 40. OHV / AV value is 1.2
If it is less than 1, the translucency of the resin decreases, the minimum melting temperature of the resin increases, and it becomes difficult to form a continuous coating film by heating and melting, or the fluidity of the powder coating decreases. Problem.

The acid value (AV) is calculated, for example, by dissolving a polyester resin in a mixed solvent of benzene and ethanol, titrating with potassium hydroxide, and calculating the neutralization amount. The hydroxyl value (OHV) is determined by, for example, acetylating a free acid in a polyester resin using a mixed solvent of pyridine and acetic anhydride (3.1: 1), and then titrating acetic acid bound to the resin with potassium hydroxide. It is calculated from the amount of neutralization by titration.

The polyester resin described above can be used alone, or may be blended with the various resins known in the prior art. When other resins are blended, the amount is preferably about 1 to 30% by weight based on the polyester resin. (Colorant) As the cyan (C) colorant, a phthalocyanine pigment is particularly preferably used. As a specific example of such a phthalocyanine pigment, for example, a general formula (2)
:

[0034]

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Wherein X ¹ , X ² , X ³ and X ⁴ are the same or different and are each a hydrogen atom, a group (2a) or a group (2b):

[0036]

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Is shown. R ³ and R ⁴ are an alkylene group having 1 to 5 carbon atoms. A copper phthalocyanine pigment represented by, for example, C.I. I. Pigment Blue 15 (15: 1 to 15: 4,
A compound wherein X ¹ , X ² , X ³ and X ⁴ are all hydrogen atoms) or a derivative thereof, or a compound of the formula (3):

[0038]

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And a metal-free phthalocyanine pigment (CI Pigment Blue 16).
The above C.I. I. Pigment Blue 15 derivatives include partially chlorinated products thereof, and barium salts of sulfonic acid of copper phthalocyanine (CI Pigment Blue 17). Examples of other cyan-based coloring agents other than the above include inorganic pigments such as navy blue (Prussian blue) and cobalt blue; I. Pigment Blue 18, C.I. I. Organic pigments such as CI Pigment Blue 16, C.I. I. Bat Blue 6, C.I. I. And dyes such as Solvent Blue 70.

The amount of the cyan-based coloring agent is such that in the case of the powder coating of cyan (C), the binder resin is taken into consideration in consideration that a vivid color tone is obtained and the light transmittance of the powder coating does not decrease. About 1 to 20 parts by weight per 100 parts by weight, especially 2
It is preferably about 8 parts by weight. In the case of a light cyan (LC) powder coating, the binder resin may vary depending on the color density of the cyan powder coating to be combined in consideration of the above-described improvement in color gradation and elimination of granularity. 1
The amount is preferably about 0.1 to 2.5 parts by weight, particularly about 0.5 to 2.0 parts by weight, per 100 parts by weight.

As the magenta (M) colorant, for example, a quinacridone pigment is used. Specific examples of such quinacridone pigments include, for example, those represented by the general formula (4):

[0042]

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[Wherein Q¹And Q^TwoAre the same or different
Represents a hydrogen atom, an alkyl group or an alkoxy group.
But Q¹, Q^TwoAre not simultaneously hydrogen atoms. ]
Quinacridone pigments such as C.I. I. Pigmentle
Head 122 [Q ¹And Q^TwoAre both methyl groups
Compound]. Also, other magenta other than the above
As the colorants of the tertiary system, for example, bengara, cadmium
Red, lead red, cadmium mercury sulfide, manganese purple, red mouth
Inorganic pigments such as graphite and molybdenum orange; I. Pi
Gment Red 3, C.I. I. Pigment Red 38,
C. I. Pigment Red 48: 2, C.I. I. Pigmen
Tread 49: 1, C.I. I. Pigment Red 49:
2, C.I. I. Pigment Red 50, C.I. I. Pigmen
Tread 57, C.I. I. Pigment Red 60, C.I.
I. Pigment Red 81, C.I. I. Pigment Red
90, permanent red FNG, C.I. I. Pig member
Iolet 3, C.I. I. Pigment Violet 25,
C. I. Pigment Orange 5, C.I. I. Pigmento
Range 13, C.I. I. Pigment Orange 16, etc.
Machine pigment, spiron red, indanthrene brilliant
Orange RK, Indanthrene Brilliant Orange G
Dyes such as K;

The amount of the magenta-based coloring agent is determined in consideration of the fact that in the case of the magenta (M) powder coating, a clear color can be obtained and that the light transmittance of the powder coating does not decrease. The amount is preferably about 1 to 20 parts by weight, particularly about 2 to 8 parts by weight, based on 100 parts by weight of the resin. In the case of a light magenta (LM) powder coating, taking into account the above-described improvement in color gradation and elimination of granularity, the binding depends on the color density of the magenta powder coating to be combined. 0.1 to 2.5 parts by weight with respect to 100 parts by weight of resin,
In particular, it is preferably about 0.5 to 2.0 parts by weight.

Examples of the yellow (Y) colorant include condensed azo pigments, isoindoline pigments, and benzimidazolone pigments. Among them, the condensed azo pigment is represented by the general formula (5):

[0046]

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Wherein R ⁵ and R ⁶ are the same or different and represent an alkyl group or a halogen atom, and R ⁷ and R ⁸ are the same or different and represent a group (5a) or (5b):

[0048]

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Is shown. A compound represented by the formula: I. Pigment Yellow 93 [R ⁵ is a methyl group, R
⁶ is a chlorine atom, and R ⁷ and R ⁸ are both groups (5a)], C.I. I. Pigment Yellow 94 (R ⁵ and R ⁶ are both chlorine atoms, R ⁷ and R ⁸ are both groups (5b)
And C.I. I. Pigment Yellow 9
5 [R ⁵ and R ⁶ are both methyl groups, R ⁷ and R ⁸
Wherein both are groups (5b).

Examples of the isoindoline pigment include, for example, those represented by the following general formula (6):

[0051]

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Wherein Ar is a group (6a) or (6b):

[0053]

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Is shown. A compound represented by the formula: I. Pigment Yellow 109 [compound wherein Ar is group (6a)], C.I. I. Pigment Yellow 110 [Ar
Is a group (6b)]. Further, as a benzimidazolone pigment, a compound represented by the formula (7):

[0055]

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(CI Pigment Yellow 154) and the like. Other yellow-based coloring agents other than the above include, for example, yellow iron oxide,
Inorganic pigments such as loess, graphite, zinc yellow, cadmium yellow, and antimony yellow; I. Pigment Yellow 1, C.I. I. Pigment Yellow 3, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 13,
C. I. Pigment Yellow 16, C.I. I. Pigment Yellow 17, C.I. I. Pigment yellow 55, C.I.
I. Pigment Yellow 65, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I.
Pigment yellow 83, C.I. I. Pigment Yellow 97, C.I. I. Pigment Yellow 98, C.I. I. Pigment yellow 115, C.I. I. Pigment Yellow 1
30, C.I. I. Pigment yellow 133, C.I. I. Pigment yellow 138, C.I. I. Organic pigments such as C.I. Pigment Yellow 169; I. Solvent Yellow 1
6, C.I. I. Solvent Yellow 33, C.I. I. Solvent Yellow 56, C.I. I. Solvent Yellow 60,
C. I. Solvent Yellow 61, C.I. I. Solvent Yellow 162, C.I. I. Acid Yellow 1, C.I.
I. Dyes such as Acid Yellow 23;

The amount of the yellow colorant to be blended is 1 to 100 parts by weight of the binder resin, considering that a vivid color tone can be obtained and that the light transmittance of the powder coating does not decrease.
It is preferably about 20 to 20 parts by weight, particularly preferably about 1.5 to 8 parts by weight. As the red (R) colorant, for example, a naphthol-based pigment is used. As a specific example of such a naphthol-based pigment, for example, a general formula (8):

[0058]

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(CI Pigment Red 170) and the like. Other red-based coloring agents other than the above include, for example, C.I. I. Pigment Red 5, C.I. I. Pigment Red 146, C.I.
I. Pigment Red 177, C.I. I. Pigment Red 178, C.I. I. Pigment Red 202, C.I. I.
Pigment Red 238, C.I. I. Pigment Red 2
51, C.I. I. Pigment Red 254, C.I. I. Pigment Red 255, C.I. I. Pigment Red 264
And other organic pigments.

The mixing amount of the red colorant is such that in the case of a red (R) powder coating, a clear color can be obtained and the light transmittance of the powder coating is not reduced. The amount is preferably about 1 to 20 parts by weight, particularly about 2 to 8 parts by weight, based on 100 parts by weight of the resin. In the case of a light red (LR) powder coating, the binding depends on the color density of the red powder coating to be combined in consideration of the above-described improvement in color gradation and elimination of granularity. It is preferably about 0.1 to 2.5 parts by weight, especially about 0.5 to 2.0 parts by weight, based on 100 parts by weight of the resin.

The clear (T) type powder coating is produced without adding the above-mentioned coloring agent. (Other Additives) In addition to the above-described components, the powder coating may further contain various conventionally known additives such as a charge control agent, a curing agent, and a leveling agent (flowing agent). Good. Among these, the charge controlling agent is used when the powder coating is used in, for example, the above-mentioned electrostatic coating method, for example, the electrostatic coating method using a spray gun, or the electrostatic flow immersion method. In addition to stabilizing regardless of changes in environmental conditions such as temperature and humidity, and matching the charging characteristics of each color powder coating, the color is adjusted by the dispersion of the mixing ratio of each color powder coating. This is to prevent fluctuations in the charging characteristics of the powder coating as a whole. Either a positive charge control agent or a negative charge control agent is used according to the charging polarity of the powder coating. .

Examples of the positive charge controlling agent include a nigrosine electron donating dye, a metal salt of naphthenic acid or a higher fatty acid, an alkoxylated amine, a quaternary ammonium salt, an alkyl amide, a chelate, a pigment, and a fluorine treatment. Activators and the like. Examples of charge control agents for controlling negative charges include electron-accepting organic complexes, chlorinated paraffins, chlorinated polyesters, polyesters having an excess of acid groups, sulfonylamine of copper phthalocyanine, aromatic oxycarboxylic acids, and aromatic dicarboxylic acids. Acids and the like.

However, in the case of a translucent powder coating, in order to have as little influence as possible on its color, (a) it is colorless or pale in itself, and (b) it is formed so as not to make the powder coating cloudy. A charge controlling agent which is excellent in compatibility with the binder resin or incompatible with the binder resin but excellent in dispersibility is preferably used.

As the positive charge controlling agent satisfying the above conditions, quaternary ammonium salts can be mentioned, and as the negative charge controlling agent, aromatic oxycarboxylic acid, aromatic dicarboxylic acid and the like can be mentioned. Among the above, the quaternary ammonium salt which is a positive charge control agent includes various compounds, and in particular, the compound represented by the general formula (9):

[0065]

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Wherein R ^a , R ^b , R ^c and R ^d are
Same or different lower alkyl group, long chain alkyl group,
A represents an alkenyl group or a benzyl group, and A ^- represents an anion. However, at least one of R ^{a to} R ^d is a long-chain alkyl group or a long-chain alkenyl group, and two are a lower alkyl group or a benzyl group. ] Are preferably used.

In the general formula (9), examples of the long-chain alkyl group corresponding to R ^{a to} R ^d include an octyl group,
Decyl group, dodecyl group, tetradecyl group, hexadecyl group, octadecyl group, eicosyl group, docosyl group, oleyl group, linolyl group, hexadecyl group and the like. Examples of the long-chain alkenyl group include, for example, a group having one or more double bonds introduced into the molecule of the long-chain alkyl group.

[0068] A ^- as the anion represented by, for example, molybdate, phosphomolybdic acid, silicomolybdic acid, chromium molybdate, bromine, molybdate, tungstate, phosphotungstic acid, silicotungstic acid, chromium, tungsten Anions, chloride ions, bromine ions, iodine ions, nitrate ions, sulfate ions derived from molybdenum atoms and inorganic acids containing tungsten atoms such as acids, bromotungstic acid, phosphotungsten / molybdic acid, and silicotungsten / molybdic acid , Perchlorate ion, benzoate ion, tetraphenylboron ion, hexafluorophosphate ion, naphtholsulfonate ion and the like.

Specific examples of the quaternary ammonium salt represented by the general formula (9) include, for example, (C ₁₆ H ₃₃ ) ₂ N ⁺
(CH ₃ ) ₂ 1/4 Mo ₈ O ₂₆ ^4- , (C ₁₆ H ₃₃ ) ₂
N ⁺ (CH ₃ ) ₂ 1/6 Mo ₇ O ₂₄ ^6- , (C
^{_{16 H 33) 2 N + (}} CH 3) 2 · 1 / 2WO 4 2- and the like, may be used by mixing one or more of them.

The charge control agent is preferably used in an amount of 1 to 10 parts by weight based on 100 parts by weight of the binder resin.
More preferably, it is 5 parts by weight. If the amount of the charge control agent is less than the above range, the effect of the addition may be insufficient.If the amount exceeds the above range, the light transmittance may decrease or the color may change. There is a possibility that. The curing agent is for curing the coating film by crosslinking the binder resin in the coating film when the powder coating is heated and melted to form a coating film. , For example, blocked isocyanates, epoxy resins,
Examples include an amino resin, an aziridine compound, and a polyvalent carboxylic acid.

A suitable range of the curing agent is set according to the equivalent of the functional group contributing to the curing reaction. If the amount of the curing agent is less than the preferred range, the effect of the addition may be insufficient.If the amount exceeds the preferred range, on the other hand, the light transmittance is reduced or the color is changed. Or The leveling agent is used to improve the fluidity of the powder coating when heated and melted to make the coating film smoother. Examples of the leveling agent include “Acronal 4F” (trade name, manufactured by BASF). "YF-3919" manufactured by Toshiba Silicone Co., Ltd. and "Modaflow 2000" manufactured by Monsanto.

The compounding amount of the smoothing agent is preferably 0.1 to 2 parts by weight based on 100 parts by weight of the binder resin,
More preferably, the amount is from 1 to 1 part by weight. If the blending amount of the leveling agent is less than the above range, the effect of the addition may be insufficient, and if it exceeds the above range, the translucency is reduced or the color is changed. There is a risk. In addition to the above, other additives such as a curing accelerator for assisting a curing reaction by a curing agent, an antifoaming agent, or an epoxy resin for enhancing corrosion resistance of a coating film are also included in the powder coating. May be blended.

(Production Method of Powder Coating) The powder coating is prepared by mixing a mixture obtained by premixing each of the above components using a dry blender, a Henschel mixer, a ball mill, or the like, for example, a jet mill, a Banbury mixer, a roll, a single screw, or the like. 2
It is manufactured by melt-kneading using a shaft extruder and kneading machine, cooling and pulverizing the obtained kneaded material, and further classifying as necessary.

In addition, it can also be produced by a polymerization method, a microcapsule polymerization method, a spray drying method, or the like. The particle size of the powder coating may be the same as the conventional one, but considering the uniformity of the color when two or more colors are mixed, the smaller the particle size is, the more preferable it is, especially the average particle size is 30 μm or less. Is preferred.

In consideration of the chargeability, the ease of forming a coating film, the difficulty of aggregation, and the like, the average particle size of the powder coating is as follows:
It is particularly preferable that the thickness be 1 μm or more within the above range.
Further, in consideration of the balance of the above properties, the average particle size of the powder coating is particularly preferably 5 to 20 μm within the above range. Various external additives may be added to the powder coating in order to improve the fluidity and charging characteristics thereof, and to match the charging characteristics for each color powder coating as described above.

The external additives include aluminum oxide,
Various conventionally known external additives having a particle size of about 1.0 μm or less, for example, fine powder of metal oxide such as silicon oxide, titanium oxide, and zinc oxide, or fine particles of fluorine resin can be used. Silica-based surface treating agents containing hydrophilic or hydrophilic silica fine particles, for example, ultrafine anhydrous silica and colloidal silica are preferably used.

The amount of the external additive to be added is not particularly limited, and may be the same as the conventional one. Specifically, with respect to 100 parts by weight of the powder coating material, the external additive is added in a total amount of about 0.1 to 3.0 parts by weight,
It is preferable to add them, but in some cases, the amount of the external additives added may be outside this range.

[0078]

[Product name ER-6680 manufactured by Nippon Ester Co., Ltd.]

-Pigment C. I. Pigment Blue 15: 3 3.0 [Ket Blue 104 (trade name, manufactured by Dainippon Ink Co., Ltd.)] -Hardener Vestagon B1530 15 (trade name, manufactured by Huls) -Curing accelerator StannOMF (trade name, manufactured by Sankyoki Gosei Co., Ltd.) 0.3 ・ Smoothing agent Dispalon PL525 1.0 (trade name, manufactured by Kusumoto Kasei Co., Ltd.) ・ Defoaming agent Benzoin 0.5 (trade name, manufactured by Midori Kagaku Co., Ltd.) ・ Epoxy resin 2.0 [Toto Kasei Co., Ltd. Epotote YD-014]
Next, 0.4 parts by weight of the produced cyan-based translucent powder coating was used as fine powder silica as a surface treatment agent for negative charging with respect to 100 parts by weight of the powder coating [Nippon Aerosil Co., Ltd.]
Product name R972] and a rotary-wing mixer [WAR
Product name COMMERCIAL manufactured by ING (Walling)
BLENDER HGB-SS] and used for toning. <Magenta translucent powder coating> C.I. I. Pigment Blue 15: 3 and the same amount (3.0 parts by weight) of C.I. I. Pigment Red 122 (trade name KetRed 309 manufactured by Dainippon Ink and Chemicals Co., Ltd.) except that pigment type 122 was used in the same manner as the cyan-based translucent powder coating material. Magenta translucent powder coatings M-0.1, M-0.5, M-1.0,
M-1.5, M-2.0 and M-3.0 were prepared, and 0.4 parts by weight of fine powdered silica [R972 described above] was also added to 100 parts by weight of the powder coating material. The mixture was stirred and mixed using the rotary blade type mixer described above, and provided for toning. The numbers in the above-mentioned abbreviations indicate the number of parts of the added pigment in the same manner as described above. <Yellow translucent powder coating> As a pigment, C.I. I. Pigment Blue 15: 3 and the same amount (3.0 parts by weight) of C.I. I. Pigment Yellow 154 [trade name: Symler Fast Yellow manufactured by Ciba-Geigy Corporation]
w4192], except that six types of yellow-based translucent powder paints Y-0.
1, Y-0.5, Y-1.0, Y-1.5, Y-2.0
And Y-3.0, and 0.4 parts by weight of finely divided silica [R97 described above, based on 100 parts by weight of the powder coating.
2) was also stirred and mixed using the rotary blade type mixer described above, and provided for toning. The numbers in the above-mentioned abbreviations indicate the number of parts of the added pigment in the same manner as described above.

<< Preparation of Basic Data >> A total of 18 types of powder coatings of C, M, and Y each produced in the above-mentioned powder coating preparation, each of which is a total of 18 types, were used as SPCC steel sheets as objects to be coated. First, a white powder coating was electrostatically adhered under the following condition I on the one side, and then electrostatically adhered under the following condition II, and then baked at 180 ° C. for 20 minutes to obtain a white powder having a thickness of about 30 μm. Samples of a coating film having a two-layer structure of an undercoat layer and a colored overcoat layer having a thickness of about 30 μm and made of the powder coating of each sample were prepared. <Condition I (coating of white underlayer)> Powder supply: quantitative feeder [prototype manufactured by Mita Kogyo Co., Ltd.], rotation speed = 380 r.p. p. m. , Scraper angle = scale 1 ・ Substrate conveying speed: 50 mm / sec ・ Coating machine: manufactured by Barcalizing, INF pressure = 3 kg
/ Cm ² G, swirling pressure = 3 kg / cm ² G, transfer pressure =
3 kg / cm ² G ・ Gun: tribo-charging gun, nozzle = fan shape ・ Booth suction air velocity: 0.59 m / sec ・ Coating distance: 300 mm ・ Coating amount: 0.7 g <Condition II (coating of colored top coat layer)> Powder supply: Same as above ・ Substrate conveying speed: Same as above ・ Coating machine: Same as above ・ Gun: Corona charging gun, applied voltage = 60 kV ・ Booth suction wind speed: Same as above ・ Coating distance: Same as above ・ Coating amount: 0.5 g The coating film of each sample was measured using a colorimeter (SE-2000 manufactured by Nippon Denshoku Co., Ltd.) as a colorimeter to create 18 basic data (wavelength-reflectance curve). did. Then, the above 18 basic data are inputted to the arithmetic unit, and the respective K / S values [(K / S) ₁ to (K / S
S) ₁₈ ] was calculated, the calculated reflectance was calculated from each K / S value, and the tristimulus value was calculated from the calculated reflectance.

The following were used as the white powder coating for the white underlayer. <White powder coating> As a pigment, C.I. I. Pigment Blue 15: 3, and the same amount of titanium oxide (trade name: CR-90, manufactured by Ishihara Techno Co., Ltd.) was used. (I)
In the same manner as in the above, a white powder coating material having a volume center particle size of 17 μm was produced. The white powder coating was used as a base without surface treatment.

<< Toning of Powder Coating >> As target colors, CF0089 (red), CF0245 (vivid green), and CF of color cards manufactured by Toyo Ink Co., Ltd.
Select each color of 0461 (purple),
The color difference meter [SE-2000 manufactured by Nippon Denshoku Co., Ltd.]
And a wavelength-reflectance curve was created.

Then, the wavelength-reflectance curve is input to an arithmetic unit to calculate a K / S value. Then, the K / S value and the basic data previously recorded in a storage device are created. An isomeric match is performed using the calculated reflectance, and the result of this isometric match and the tristimulus values obtained in the preparation of the basic data previously recorded in the storage device are used. The type of powder paint of each color of C, M, and Y necessary to reproduce each of the above-mentioned target colors by performing a metameric match (the above-described type due to the difference in the number of pigments), and the compounding ratio (weight) %).

The results are shown in Tables 1 to 3, respectively.

[0084]

[Table 1]

[0085]

[Table 2]

[0086]

[Table 3]

<< Evaluation of Toning >> Based on the results shown in Tables 1 to 3, powder coatings of each color were measured using a measuring device, and the powder coating was mixed with the above-mentioned rotary blade type mixer as a mixing device. Supply 2
Dry blended for 5 seconds. Then this toned 3
Each kind of powder paint, first, on one side of the SPCC steel plate as an object to be coated, on which a white powder paint was electrostatically adhered under the condition I, and then electrostatically adhered under the condition II, Then 1
Baking at 80 ° C. for 20 minutes, a 30-35 μm-thick white base layer and 30-35 μm-thick powder coatings
m having a two-layer structure of a colored overcoat layer having a total thickness of 6
A coating film of 5 μm was produced.

Each coating film is measured using the colorimeter [SE-2000 manufactured by Nippon Denshoku Co., Ltd.], and the colorimetric data of the color card is used as a target color. Calculate the color difference Δ デ ー タ^* from the data, and determine that the color difference ΔΕ ^* is less than or equal to the threshold value 0.8 without color shift (○),
Those exceeding 0.8 were evaluated as having a color shift (x). Table 4 shows the results.

[0089]

[Table 4]

From the table, all of the above three types of powder coatings
It was confirmed that the color was well toned without color shift from the target color.

[0091]

As described in detail above, according to the present invention,
A new method of toning powder paints, which does not cause variations in toning results due to internal or external factors affecting the operator during toning work, and a toning system for implementing it Can be provided.

[Brief description of the drawings]

FIG. 1 is a flowchart showing each step of an example of a toning method of the present invention.

FIG. 2 is a flow chart showing a step of calculating a calculated reflectance and tristimulus value from a plurality of basic data measured in advance for each of a plurality of color powder coatings to be used in the toning method.

FIG. 3 is a block diagram showing an example of the toning system of the present invention for implementing the toning method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Colorimeter 2 Computing device 3 Measuring device 4 Mixing device

Continuation of the front page (56) References JP-A-7-225145 (JP, A) JP-A-6-279716 (JP, A) JP-A-61-19675 (JP, A) Yukio Murayama, Industrial Colorimetry, Japan, Textile Company, June 15, 1969, 364-379 (58) Field surveyed (Int. Cl. ⁷ , DB name) C09D 7/14 C09D 5/03 G01J 3/46

Claims (4)

(57) [Claims] 1. A toning method in which a plurality of translucent powder paints are blended in a predetermined ratio, and dry-blended to produce a toned color. From the reflectance curve, K / S which is the ratio between the light absorption coefficient K and the scattering coefficient S
Then, the K / S value is different from the color density of each of a plurality of translucent powder paints to be used.
Isomeric match using the calculated reflectance calculated from the K / S values [(K / S) ₁ to (K / S) _n ] of n pieces of basic data obtained by forming a plurality of coating films and measuring the color. Then, a metameric match is performed using the result of the isomeric match and the tristimulus value calculated from the calculated reflectance to calculate the compounding ratio of the powder paint of each color. A method for toning a powder coating, characterized in that a powder coating of each color is weighed and dry blended. 2. The dry-blended powder coating is further subjected to test coating under the same conditions as the actual coating, and the obtained coating film is measured for color. The method for toning a powder coating according to claim 1, further comprising a step of correcting and calculating the compounding ratio of the powder coating. 3. A system for implementing the method for toning a powder coating material according to claim 1, wherein: (a) a colorimetric device for measuring a target color to create a wavelength-reflectance curve. (B) calculating a K / S value, which is a ratio between the light absorption coefficient K and the scattering coefficient S, from the wavelength-reflectance curve, and calculating the K / S value and a plurality of colors to be used in advance . For translucent powder coatings , multiple coatings with different color densities were formed.
K / S values of the n basic data obtained by measuring Te [(K / S) ₁
~ (K / S) _n ], an isometric match is performed using the calculated reflectance, and a metameric match is performed using the result of the isometric match and the tristimulus value calculated from the calculated reflectance. (C) a mixing device for dry blending a plurality of translucent powder paints, and (d) a calculation device for calculating the blending ratio of the powder coatings of each color. A metering device for metering a predetermined amount of the powder paint based on the measured amount and supplying the powder paint to the mixing device. 4. An arithmetic unit corrects and calculates the compounding ratio of the powder coating of each color from colorimetric data obtained by colorimetrically measuring a coating film obtained by test coating under the same conditions as actual coating. 4. The powder coating color toning system according to claim 3, which also has a function.