JPH11279464A - Method for toning powder coating, and toning system for its application - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for toning powder paint and to provide a system for its application, capable of forming coating film having uniform color combination without color segregation, motted feeling, variation in color strength, or the like, even when dry-blending a plurality of sorts of powder coatings each having different color from each other. SOLUTION: This first method for toning is to contact the periodical color measurement of a powder coating sample in dry blending in order to find the dry blending time required for the color difference ΔE* between the newest color measurement value and the last one to become 0.8 or below, and to really apply it to the dry blending of powder coatings. The second method for toning is to conduct the periodical color measurement of a powder coating in dry blending and to terminate the dry blending when the above color difference ΔE* becomes 0.8 or below. The system for this method controls a mixer 1 by means of a controller 2, based on the color difference ΔE* known by the result of the color measurement with a measurement equipment 3.

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, a powder coating of a plurality of colors previously adjusted to so-called three primary colors, such as cyan (C), magenta (M), and yellow (Y), particularly a translucent powder coating colored in each color. It has been studied to formulate powder paint having a predetermined color tone by blending according to the target color tone, dry blending using a mixing device such as a rotary wing type mixer, and mixing the colors. I have.

However, when the above-mentioned toning method is actually performed, it is found that defects such as color segregation, mottle, and shading tend to occur in a coating film formed by using the powder coating after toning. There was a problem. An object of the present invention is to form a coating film having a substantially uniform tint without defects such as color segregation, mottle, and shading despite dry blending of powder coatings of a plurality of colors. It is an object of the present invention to provide a new method of toning a powder coating material and a toning system for implementing the method.

[0008]

Means for Solving the Problems In order to solve the above problems, the present inventors first studied the causes of the above-mentioned various defects in the coating film. As a result, after blending powder paints of multiple colors according to the target color, when dry blending using a mixing device, conventionally, the degree of the mixing is visually checked by the operator. The powder paint is not sufficiently dry-blended due to the combination of shades of the powder paint to be adjusted (for example, a combination of similar colors) or individual differences between workers, or the reverse. It was clarified that the excessively dry-blended state caused various defects such as color segregation, mottle, and shading.

In other words, if the dry blending is insufficient, the aggregates of the powder coating for each color are not sufficiently disintegrated. Therefore, if the dry blends are excessive due to such aggregates, In any of these cases, the granularity of the coating film becomes so large as to be visible because of the aggregation of the powder coating, and defects such as color segregation, mottle and shading occur.

Therefore, as a result of studying to solve such a problem and to quantify the state of the dry blend of the powder coating so as not to be affected by the combination of shades of the powder coating to be adjusted and individual differences among workers, The powder paint in the middle of dry blending is sampled at regular intervals, and the hue in the powder state is measured using a colorimeter such as a colorimeter to measure the latest and previous colorimetric values. It can be found that the color difference ΔΕ ^* with the above should be obtained.

That is, in the initial stage of dry blending,
The color difference ΔΕ ^* shows a high value because the aggregates of the powder coating material are disintegrated and the hue changes greatly, but as the disintegration of the aggregates progresses, the change in hue gradually decreases. In addition, the color difference ΔΕ ^* also gradually decreases. Then, when the dry blending is sufficiently performed without excess or shortage, the hue hardly changes, so that the color difference Δ 差^* shows an almost stable value equal to or less than a certain value. However, if the dry blending is further continued in this state, on the contrary, the aggregation of the powder coating proceeds and the hue changes again, so that the color difference ΔΕ ^* tends to increase again.

Then, the inventors next show a state in which the above-mentioned dry blending has been sufficiently performed without excess or deficiency, and a powder which does not cause defects such as color segregation, mottle, and shading when formed into a coating film. As a result of further study on the range of the color difference ΔΕ ^{* from which} a paint can be obtained, the present invention has been completed. That is, the method for adjusting the color of the powder coating of the present invention is performed in advance, while the powder coating sample is dry-blended using the same mixing device as that actually used,
The hue in the powder state is measured at regular intervals, and the dry blending time required for the color difference ΔΕ ^* between the latest color measurement value and the previous color measurement value to be 0.8 or less is calculated ^. Based on the result, the time for dry blending of the actual powder coating is set.

Further, another method of toning a powder coating according to the present invention is as follows.
The powder coating in the middle of dry blending is sampled at regular intervals, and the hue in the powder state is measured, and the color difference ΔΕ ^* between the latest color measurement value and the previous color measurement value is 0.8 or less. It is characterized in that the dry blending is terminated at the point of time. In addition, for performing the above-described color-toning method of the present invention, the powder-color-toning system of the present invention comprises: (i) a mixing device for dry-blending powder paints of a plurality of colors; While dry blending the placed powder coating sample using the same mixing device, the hue in the powder state of the sample in the middle is measured at regular intervals and the latest colorimetric value and the previous colorimetric value Based on the dry blending time required for the color difference ΔΕ ^* with the colorimetric value of 0.8 or less to be 0.8 or less, the dry blending time of the actual powder coating is set, and based on that setting, A control device for controlling the mixing device, or (a) a mixing device for dry-blending powder coatings of a plurality of colors; and A colorimeter for measuring the hue in the body state, and (c) the above colorimeter According to end the dry blend at the time the color difference [Delta] [epsilon] ^* becomes 0.8 latest colorimetric values and colorimetric values of the preceding, characterized in that it comprises a control device for controlling the mixing device It is assumed that.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below. First, a first toning method of the present invention and a toning system for implementing the method will be described. A toning system for implementing the first toning method is, for example, as shown in FIG.
A mixing device 1 for dry-blending powder paints of a plurality of colors and samples thereof, a control device 2 for controlling conditions such as time and speed of dry blending in the mixing device 1, and an input to the control device 2 In order to determine the time for dry blending the powder coating with the mixing device 1,
It comprises a colorimeter 3 for measuring the hue of the sample in the powder state during the dry blending. In the drawing, reference numeral 4 denotes a measuring device for measuring a predetermined amount of the powder coating material and supplying it to the mixing device 1. Further, as the mixing device 1 used in the above system,
For example, a rotary wing type mixer or the like can be cited, and as the colorimetric device 3, for example, a colorimeter or the like can be cited.

In the first toning method of the present invention using such a system, first, predetermined amounts of powder paint samples of a plurality of colors are weighed using the weighing device 4 and supplied to the mixing device 1. Then, as shown in FIG. 1, dry blending (sample blending) is started [step S1].
Next, a part of the sample during the dry blending is sampled from the mixing device 1, and the hue in the powder state is
The colorimeter 3 is used to measure the color at regular intervals such as every 2 to 5 seconds [Step S2].

[0016] and this operation, repeated until the color difference ΔΕ of the latest color measurement value and the measured color value of the last time ^* is 0.8 or less [step S3 → S2], the color difference ΔΕ ^* 0.8
When the following conditions are satisfied, the sample blending is terminated [Step S4], and the time required for the sample blending up to that time is measured [Step S5]. Next, based on the above results, the time for dry blending of the actual powder coating using the mixing device 1 is set, and the time is input to the control device 2 together with other conditions such as the speed of dry blending. At the same time, the powder paints of the plurality of colors to be dry-blended are measured by a predetermined amount using the measuring device 4 and supplied to the mixing device 1.

When the mixing device 1 is operated based on a control signal from the control device 2, the dry blending is sufficiently performed without excess or shortage, and when the coating is formed, color segregation, mottling, shading, etc. A toned powder coating which does not cause defects can be obtained. As the powder coating of the sample used in the above-mentioned toning method, a coating having the same composition as that of the powder coating which is actually toned by dry blending using the mixing apparatus is used. In particular, the same powder coating is preferred. However, the combination of the colors of the sample may or may not be the same as the combination of the colors of the powder paint to be actually dry-blended.

When the same mixing apparatus 1 is used for toning a plurality of types of powder coatings, for example, data of samples may be prepared for each powder coating in advance. In addition, it is preferable to take sample data each time the lot changes for the same type of powder coating. In the mixing apparatus 1, conditions other than the time of the dry blending, such as the speed of the dry blending, are preferably set to coincide between the dry blending of the powder paint and the dry blending of the sample. The dry blending time data required for the color difference ΔΕ ^{* to} be 0.8 or less, obtained by dry blending the sample, can be directly applied to the dry blending time of the actual powder coating.

However, when the relational expression between the dry blending time and other conditions is clear, the other conditions are not necessarily the same between the time of dry blending of the powder paint and the time of dry blending of the sample. The dry blending time data required for the color difference ΔΕ ^{* to} be 0.8 or less, obtained by dry blending the sample, may be converted based on the above relational expression to obtain the actual powder. It may be applied to the time of dry blending of the body paint.

According to the first toning method of the present invention,
Once the sample data is obtained and recorded in the control device 2 in the form of, for example, electronic information, or in an external storage device (not shown), when the same type of powder paint is toned, There is an advantage that it is not necessary to take sample data every time. Next, the second toning method of the present invention will be described.

The toning system for implementing the second toning method is basically the same as the system for implementing the first toning method. That is, as shown in FIG. 4, the toning system of the present invention includes a mixing device 1 and a control device 2.
, A colorimetric device 3, and a measuring device 4.
However, in the present invention, the data measured by the colorimeter 3 is sequentially input to the controller 2, and an arithmetic unit (not shown) provided in the controller 2 calculates ΔΕ ^* in order to calculate the ΔΕ ^* .
The control device 2 and the colorimetric device 3 are connected as indicated by an alternate long and short dash line arrow in the figure.

In the second toning method of the present invention using such a system, first, a predetermined amount of powder paint of a plurality of colors is weighed using a weighing device 4 and supplied to a mixing device 1. Then, as shown in FIG. 3, the dry blending is started [step S11]. Next, a part of the powder coating in the middle of the dry blending is sampled from the mixing device 1 and the hue in the powder state is measured using the colorimeter 3 at regular intervals such as every 2 to 5 seconds. (Step S12).

Then, as described above, the colorimetric data is sequentially input to the control device 2, and the arithmetic unit in the control device 2 causes the color difference ΔΕ ^* between the latest colorimetric value and the previous colorimetric value ^.
Is calculated. This operation is automatically repeated until the color difference ΔΕ ^* becomes 0.8 or less while continuing the dry blending by the mixing device 1 [Step S13
→ S12], when the color difference ΔΕ ^* becomes 0.8 or less,
The mixing device 1 is automatically stopped by the control signal from the control device 2, and the dry blending ends (step S14).

According to the second toning method of the present invention,
There is an advantage that it is not necessary to take sample data in advance, and in a real dry blend, the optimum mixing state can be automatically derived. The first and second methods for toning powder coatings of the present invention described above and a toning system for carrying out the methods may be provided as independent methods and systems. As shown in FIG. 5, it may be incorporated in a powder paint automatic toning system that automatically performs from the color measurement of a target color to the preparation of a plurality of powder paints and toning.

In such an automatic toning system, first,
A color sample of a target color or the like is measured using a colorimeter such as the above-described colorimeter to create a wavelength-reflectance curve [Steps S1 and S2]. Next, from the data of the wavelength-reflectance curve, Kubelka-Munch
Based on Munk's law, a K / S value, which is a 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 S.
3].

Next, as shown in FIG. 6, the K / S value and a plurality of basic data 1 previously measured for each of a plurality of powder coating materials to be used, for example, by changing the color density. K / S values of [(K / S) ₁ to (K
/ S) _n ] to perform an isometric match using the calculated reflectivity to match the spectral reflectance curves [Step Sa4], and then calculate from the isomeric match results and the calculated reflectivity. By performing a metameric match using the tristimulus values and matching the tristimulus values, the compounding ratio of the powder coating of each color is calculated [Step Sa]
5].

Next, based on the calculation results, the powder coating materials of each color are measured using the measuring device 4 [Step Sa].
6] Then, the powder coating material is supplied to the mixing device 1 and dry-blended with each color powder coating by the first or second toning method of the present invention described above [Step Sa7]. Next, until the color difference ΔΕ ^* becomes 0.8 or less as described above, the dry blending is terminated at a stage where the dry blending is sufficiently performed without excess or shortage, and a toned powder coating material is obtained. After a test coating of the powder coating under the same conditions as the actual coating [Step S
a8] The color of the coating film is compared with a color sample of a target color, which was measured first, to determine whether there is any color deviation [Step Sa9]. For this determination, a colorimetric device such as a colorimeter is used.

If there is a color misregistration in this determination, based on the colorimetric data obtained by the above colorimetric device,
Correction calculation of the mixing ratio of the powder coating of each color [Step Sa1
0], and based on the result, steps Sa6 to Sa9 again
repeat. Then, in the determination of step Sa9,
The toning of the powder paint is completed when there is no color difference between the color of the coating film and the color sample of the target color measured first.

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 to reproduce an orange color. 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 respective components constituting the powder coating of a plurality of colors used in the toning method of the present invention are not limited to these, but include, for example, 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-mentioned binder resins, styrene resins, acrylic resins and polyester resins are particularly preferable. Among them, (i)
(1):

[0033]

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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 acid 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 copolycondensing the above components at a temperature of 180 to 250 ° C. in an inert gas atmosphere, for example. 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 benzene-ethanol mixed solvent, 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 resins 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)
:

[0043]

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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):

[0045]

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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):

[0047]

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And a non-metallic 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):

[0051]

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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]. In addition, 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 mixing amount of the magenta-based coloring agent is such that in the case of the magenta (M) 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 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 a condensed azo pigment, an isoindoline pigment, and a benzimidazolone pigment. Among them, the condensed azo pigment is represented by the general formula (5):

[0055]

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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):

[0057]

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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-based pigment include, for example, those represented by the general formula (6):

[0060]

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

[0062]

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FIG. 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):

[0064]

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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-based colorant is 1 to 100 parts by weight of the binder resin in consideration of the fact that a clear color is 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):

[0067]

Embedded image

(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 compounding amount of the red coloring agent is such that in the case of the red (R) powder coating, a clear color is obtained, and further, considering that the translucency of the powder coating does not decrease, the binder is selected. 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) powder coating is produced without adding the above 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 alkylamide, 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 light-transmitting powder coating, (a) it is colorless or light-colored in itself and (b) it is formed so as not to make the powder coating cloudy in order to have as little influence as possible on its color. 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 control agent satisfying the above conditions, quaternary ammonium salts can be mentioned, and as the negative charge control 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):

[0074]

Embedded image

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.

[0077] 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 compounding amount of the charge control agent is preferably 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 blending amount of the leveling 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) For powder coating, a mixture obtained by premixing each of the above-mentioned components using a dry blender, a Henschel mixer, a ball mill, or the like is used, for example, a jet mill, a Banbury mixer, a roll, a single screw or 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 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, etc., 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.

[0087]

[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. Trade name of Epotote YD-014] Next, 0.4 parts by weight of fine powder silica as a surface treatment agent for negative charging was added to 0.4 parts by weight of the produced cyan translucent powder coating based on 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 (M) -based translucent powder paint> As a pigment, 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 Inc.), except that a magenta translucent powder paint having a volume center particle diameter of 13 μm is used in the same manner as the cyan translucent powder paint. Is prepared, and 0.4 parts by weight of fine powder silica (R972 described above) is mixed with 100 parts by weight of the powder coating material by stirring using the rotary blade type mixer described above. It was subjected to toning. <Yellow (Y) -based translucent powder paint> 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: Symuler Fast Yel manufactured by Ciba-Geigy Corporation]
low 4192], except that a yellow-based translucent powder paint having a volume center particle diameter of 13 μm was produced in the same manner as the cyan-based translucent powder paint, and 100 parts by weight of the powder paint was used. 0.4 parts by weight of finely divided silica [R9
72] was also stirred and mixed using the rotary blade type mixer described above, and provided for toning. <Red (R) -based translucent powder paint> As a pigment, C.I.
I. Pigment Blue 15: 3 and the same amount (3.0
Parts by weight) of C.I. I. Pigment Red 170 [trade name of Brilliant Carmine manufactured by Sanyo Dyeing Co., Ltd.]
709], except that a red-based translucent powder paint having a volume center particle diameter of 13 μm was produced in the same manner as the cyan-based translucent powder paint, and 100 parts by weight of the powder paint. 0.4 parts by weight of finely divided silica [R972 mentioned above]
This was also stirred and mixed using the rotary blade type mixer described above, and provided for toning. <Clear (T) -based translucent powder coating> A clear-based translucent powder coating having a volume center particle diameter of 13 μm in the same manner as the cyan-based translucent powder coating except that no pigment was blended. Is prepared, and 0.4 parts by weight of fine powder silica (R972 described above) is mixed with 100 parts by weight of the powder coating material by stirring using the rotary blade mixer described above, It was subjected to toning.

<< Toning of Powder Coatings >> Among the powder coatings of the respective colors prepared above, four kinds of translucent powder coatings of C, M, Y and T were used. The mixture was blended at a blending ratio (parts by weight), and the mixture was charged into the above-mentioned rotary blade type mixer as a mixing device for dry blending, and dry blending was started.

[0089]

[Table 1]

Next, the powder coating materials during the dry blending were sampled at 1 second, 3 seconds, 6 seconds, and 10 seconds after the start of the dry blending, and after 60 seconds at intervals of 5 seconds from the beginning of the 10 seconds. Then, the hue in the powder state,
Colorimeter as a colorimeter [SE manufactured by Nippon Denshoku Co., Ltd.]
-2000]. Then, a color difference ΔΕ ^* between the latest colorimetric value and the previous colorimetric value was obtained, and the transition was recorded. FIG. 7 shows the results. Note that in FIG.
Is-■-■-, and Formulation Example 2 is -−-−- (Formulation Example 2).

From the figure, it was confirmed that the color difference ΔΕ ^* was 0.8 or less (indicated by a dashed line in the figure) at 25 seconds after the start of the dry blending in both Formulation Examples 1 and 2. << Formation of Coating Film >>
10 seconds after the start of dry blending before Ε ^* became 0.8 or less, and color difference ΔΕ ^* became 0.8 or less,
Samples obtained at 25 seconds after the start of the dry blending were powdered as shown in Table 2 below.
To D.

[0092]

[Table 2]

Then, a white powder coating was electrostatically adhered to one surface of an SPCC steel plate as an object to be coated under the following condition I, and each of the powder coatings A to D was applied to the following II, respectively. And then baked at 180 ° C. for 20 minutes to form a white underlayer having a thickness of about 30 μm and powder coatings A to
A sample of a coating film composed of D and having a two-layer structure of a colored overcoat layer having a thickness of about 30 μm was 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 transport 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: 0.5g White, white The following was used as the white powder coating for the 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.

<< Evaluation of Coating Film >> The coating film of each of the above samples was visually observed, and the presence or absence of defects such as color segregation, mottle, and shading was observed. As a judgment method, the coating film is 20 cm
Good when the color segregation, mottled feeling, shading, etc. are not visible even when observed from the position of (good), and poor when the above-mentioned defect can be clearly seen when the coating film is observed from a position of 40 cm (bad). In the middle, that is, when the above-mentioned defect
Although it is not visible when observed from the position of 0 cm, it is 20 cm
Observed from the position of is slightly poor (△).

Table 3 shows the results.

[0096]

[Table 3]

From the table, in each of the coating films using the powder coatings A and C for the overcoat, defects such as color segregation, mottled feeling, and shading were observed, but the powder coatings B and D were used for the overcoat. These defects were not seen in the coated film, and it was found that the coated film had a substantially uniform tint. From this, it was confirmed that the powder coating should be dry-blended until the color difference ΔΕ ^* becomes 0.8 or less when toning the powder coating.

[0098]

As described in detail above, according to the present invention,
A new powder that can form a coating film with almost uniform tint without defects such as color segregation, mottle, and shading despite dry blending of multiple color powder coatings The present invention has a specific effect of being able to provide a method for toning a paint and a toning system suitable for implementing the method.

[Brief description of the drawings]

FIG. 1 is a flow chart showing an example of a step of obtaining a dry blending time of a powder coating from a color difference ΔΕ ^* of a powder coating sample in the first toning method of the present invention.

FIG. 2 is a block diagram showing an example of the toning system of the present invention for implementing the first toning method of the present invention.

FIG. 3 is a flowchart showing an example of a second toning method of the present invention.

FIG. 4 is a block diagram showing an example of a toning system of the present invention for implementing a second toning method of the present invention.

FIG. 5 is a flow chart showing an example of an automatic toning system for a powder paint, which automatically performs from the color measurement to the toning of a target color.

FIG. 6 is a flowchart showing a process of calculating a calculated reflectance and a 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 automatic toning system. .

FIG. 7 is a graph showing the transition of the color difference ΔΕ ^* with the lapse of dry blending time when the powder coating materials of Formulation Examples 1 and 2 are dry blended.

[Description of Signs] 1 Mixing device 2 Control device 3 Colorimetric device

Claims (4)

[Claims] 1. A powder paint of a plurality of colors is blended in a predetermined ratio,
This is a toning method in which a powder coating sample is dry-blended using the same mixing device, and a sample in the middle of the hue in a powder state is dry-blended using a mixing device. Is measured at regular intervals, and the dry blending time required for the color difference ΔΕ ^* between the latest colorimetric value and the previous colorimetric value to be 0.8 or less is determined, and the result is used as a basis. A method for toning a powder coating, characterized by setting the time for dry blending of the actual powder coating. 2. A powder paint of a plurality of colors is blended in a predetermined ratio,
This is a toning method in which color mixing is performed by dry blending using a mixing device.The powder paint during dry blending is sampled at regular intervals, and the hue in the powder state is measured. The color difference ΔΕ ^* between the value and the previous colorimetric value is 0.8
A method for toning a powder coating, wherein the dry blending is terminated when the following conditions are satisfied. 3. A system for carrying out the method for toning a powder paint according to claim 1, wherein (i) a mixing device for dry-blending powder paints of a plurality of colors; While dry blending the placed powder coating sample using the same mixing device, the hue in the powder state of the sample in the middle is measured at regular intervals and the latest colorimetric value and the previous colorimetric value Based on the dry blending time required for the color difference ΔΕ ^* with the colorimetric value of 0.8 or less to be 0.8 or less, the dry blending time of the actual powder coating is set, and based on that setting, A control system for controlling a mixing device, comprising: a color mixing system for a powder coating. 4. A system for carrying out the method for toning a powder paint according to claim 2, wherein (a) a mixing device for dry-blending powder paints of a plurality of colors; A colorimeter that samples the powder paint at regular intervals and measures the hue in the powder state; and (c) the colorimeter between the latest colorimetric value obtained by the colorimeter and the previous colorimetric value. Color difference ΔΕ ^*
And a control device for controlling the mixing device so that the dry blending is terminated when the value becomes 0.8 or less.