JP2899966B2 - Powder paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder coating which gives a coating film having a uniform hue even when two or more powder coatings having different hues are mixed and applied. A combination of powder coatings that gives a coating film having a uniform hue even when mixed and applied, a powder coating composition comprising two or more of such powder coatings, and a uniform coating using such a powder coating or powder coating composition. The present invention relates to a coating method for obtaining a hue coating film, and a resulting uniform hue coating film and coated product.

[0002]

2. Description of the Related Art Conventionally, powder coatings are prepared by adding several color pigments for producing a desired hue to a resin, a curing agent, an additive, etc., mixing, then melt-kneading, then cooling, pulverizing, and classifying. By doing so, it has been manufactured. For this reason, it is inevitable to prepare a paint for each required hue as a powder paint, and an enormous number of products are available.

On the other hand, in order to simplify the process of toning a powder coating, a powder coating in which several kinds of colored powders are mixed has been proposed.

[0004] However, when two or more kinds of powder paints having different hues are uniformly mixed and used as a powder paint,
When a powder coating having a particle size larger than 20 μm is used, particles of the powder coating of each color can generally be visually identified, so that a coating film having a uniform hue cannot be obtained.

On the other hand, as disclosed in Japanese Patent Publication No. 4-504431, a method of mixing two or more powders of 20 μm or less to obtain a coating film having a desired hue has been proposed.
μm or less, and 20 μm
In the following, there are drawbacks such as poor fluidity due to easy aggregation and difficult handling.

Further, a method of improving the fluidity by granulating a powder coating by adding a granulating agent solution or the like has been proposed, but this leads to an increase in cost due to an increase in the number of manufacturing steps.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and is intended to provide a powder having a uniform hue even when two or more powder coatings having different hues are mixed and applied. It is an object of the present invention to provide a body paint, a combination of such powder paints, and a powder paint composition comprising two or more of such powder paints.

Further, the present invention provides a coating method for obtaining a coating film having a uniform hue using the powder coating or the powder coating composition, and a coating film and a coating product having a uniform hue obtained. Aim.

[0009]

Means for Solving the Problems The inventors of the present invention do not independently set heat at 250 ° C. or lower, but when mixed and applied with other types of powder coatings, they are melt-mixed and homogenized and heat-set. A powder coating which can give a coating film with a more uniform hue was found. In particular, it has been found that when such a powder coating is used, a coating film having a uniform hue can be obtained even with a particle size of 20 μm or more, and it can be used without being particularly affected by the particle size of the powder coating. . The present invention has been completed based on such findings.

That is, the gist of the present invention is: (1) A powder coating used in a coating method for obtaining a coating film having a uniform hue by mixing and coating two or more powder coatings having different hues. Although it does not thermally cure at 250 ° C. or less by itself, it can be cured by mixing with another type of powder coating.
Powder coating having a property of thermosetting at 50 ° C. or less; (2) acrylic resin having carboxyl group, polyester resin, polyester polyamide resin, polyamide resin, acrylic resin having amino group, resin having phenolic hydroxyl group, and acid anhydride A powder coating mixed and applied with a powder coating containing at least one resin selected from the group consisting of a series of resins, wherein the powder coating is an epoxy resin, an acrylic resin having a glycidyl group, and an unsaturated resin. (1) a powder coating material according to the above (1), which comprises one or more resins selected from the group consisting of a resin having a bond, (3) an epoxy resin, an acrylic resin having a glycidyl group, and an unsaturated bond. A powder coating mixed and applied with a powder coating containing at least one resin selected from the group consisting of resins having A powder selected from the group consisting of acrylic resins having carboxyl groups, polyester resins, polyester polyamide resins, polyamide resins, acrylic resins having amino groups, resins having phenolic hydroxyl groups, and acid anhydride resins. The powder coating according to the above (1), which contains the resin described above, (4) the powder coating according to any one of the above (1) to (3), wherein the average particle diameter is 1 μm or more and 50 μm or less. (5) A method in which two or more kinds of powder coatings having different hues are used in combination. Each of them does not thermoset at a temperature of 250 ° C. or less alone, but is heat-cured by mixing and coating two or more kinds to obtain a uniform hue. A method of using a combination of powder coatings having the property of forming a coating film of (6) in a resin of a powder coating having two different hues,
One or more resins selected from the group consisting of an acrylic resin having a carboxyl group, a polyester resin, a polyester polyamide resin, a polyamide resin, an acrylic resin having an amino group, a resin having a phenolic hydroxyl group, and an acid anhydride resin A resin, and the other resin is at least one resin selected from the group consisting of an epoxy resin, an acrylic resin having a glycidyl group, and a resin having an unsaturated bond. (7) In a combination using a powder coating further containing a curing agent, the curing agent does not react with a resin mixed in the same powder coating, and other powders to be combined are used. The powder paint described in the above (5) or (6), which reacts with the resin blended in the body paint, is used in combination. (8) The above (5) to (5), wherein the difference in melt viscosity of each powder coating at a temperature of 90% of the curing start temperature of a mixture of two or more powder coatings having different hues is within 20 pa · s. 7)
(9) A powder coating composition containing two or more types of powder coatings having different hues, each of which is not independently thermoset at 250 ° C. or lower, A powder coating composition comprising two or more powder coating materials having a property of forming a coating film having a uniform hue by heat-curing by mixing and coating two or more types; (10) two types; Among the resins of powder coatings having different hues, one resin has an acrylic resin having a carboxyl group, a polyester resin, a polyester polyamide resin,
A polyamide resin, an acrylic resin having an amino group, a resin having a phenolic hydroxyl group, and one or more resins selected from the group consisting of an acid-based resin, the other resin being an epoxy resin, an acrylic resin having a glycidyl group, and The powder coating composition according to the above (9), which is at least one resin selected from the group consisting of resins having an unsaturated bond, (11) the powder coating composition according to any one of the above (1) to (4). (12) A coating method characterized by giving a coating film having a uniform hue by mixing and coating two or more kinds of powder coatings by a method according to any one of the above (5) to (8). (13) A coating method characterized by giving a coating film having a uniform hue by applying the powder coating composition according to the above (9) or (10). Coating method characterized by providing a film, and (14) above (11) to (13) either homogeneous hue obtainable by applying the coating method described coating Sobutsu relates.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The powder coating of the present invention is a powder coating used in a coating method for obtaining a coating film having a uniform hue by mixing and coating two or more powder coatings having different hues. However, it does not thermoset at a temperature of 250 ° C. or less by itself, but has the property of thermosetting at a temperature of 250 ° C. or less when mixed and applied with another type of powder coating.

In the present specification, a coating film having a "uniform" hue means that the color of each mixed powder coating cannot be visually discriminated because the hue of the formed coating film is uniform. Means that

As the resin used in the powder coating of the present invention, conventionally known resins can be used without any particular limitation. In the present invention, each resin used is baked at the time of baking. It is preferable to adjust the melting temperature so that both melt. By adjusting the melting temperature of the resin used, the resin is melted together during baking, uniformly mixed, and then cured, so that a coating film having a uniform hue can be obtained. The melting temperature of the resin can be adjusted, for example, by adjusting the chemical structure of the resin and adjusting the molecular weight distribution.

In the present invention, for example, as described above, when two types of powder coatings which are not thermoset at 250 ° C. or less by themselves are respectively a powder coating and a powder coating, the resin used for the powder coating is By properly selecting the combination of resins used in the powder coating and performing preparations according to each aspect, each of them does not thermoset at a temperature of 250 ° C. or less alone, but is melt-mixed with each other by mixing and coating two or more. It is possible to prepare a powder coating material that can be thermally cured at 250 ° C. or lower to form a coating film.

That is, in the present invention, the resins contained in the powder coating are melt-mixed to form a resin having a 250
A mode in which a curing reaction occurs at a temperature of not more than 250 ° C., and a resin and a resin alone do not cause a curing reaction at a temperature of 250 ° C. or less even if they are melt-mixed. There is a mode to cause.

Hereinafter, each embodiment will be described.

(1) Embodiment in which Resins Initiate Curing Reaction In this embodiment, as described above, the resins contained in the powder coating can be melt-mixed to cause a curing reaction at 250 ° C. or lower. In this embodiment, a resin is used.

In this embodiment, one of the resins serves as a curing agent for the other resin only after the resins used in the respective powder coatings are melted during baking and uniformly mixed. Since a curing reaction occurs, the resulting coating film has a uniform hue. Therefore, it is necessary to select a combination of the functional groups of each resin so that one resin has a functional group having a function that can serve as a curing agent for the other resin.

Examples of combinations of functional groups capable of causing a curing reaction include a carboxyl group and a glycidyl group, an amino group and a glycidyl group, and a phenolic hydroxyl group and a glycidyl group.

Therefore, it is necessary to select the resin used for each powder coating so that the combination of the functional groups possessed by each resin is the combination described above.

Therefore, the powder coating used in this embodiment is:
For example, when displaying as powder coating A and powder coating B,
Combination of resin used for powder coating A and resin used for powder coating B (resin used for powder coating A / powder coating B
Examples of the resin used for this purpose include, for example, an acrylic resin / epoxy resin having a carboxyl group, a polyester resin / epoxy resin, a polyester polyamide resin / epoxy resin, a polyamide resin / epoxy resin, an acrylic resin / epoxy resin having an amino group, and phenol. Resin having a hydroxyl group / epoxy resin, acid anhydride resin / epoxy resin, acrylic resin / epoxy resin, amino polyacrylamide resin / epoxy resin, melamine resin / epoxy resin, polyester polyamine resin / epoxy resin, acrylic resin having carboxyl group / Acrylic resin having glycidyl group, polyester resin / acrylic resin having glycidyl group, polyester polyamide resin / acrylic resin having glycidyl group, polyamide resin / having glycidyl group Acrylic resin, acrylic resin having an amino group / acrylic resin having a glycidyl group, resin having a phenolic hydroxyl group / acrylic resin having a glycidyl group, acid anhydride resin / acrylic resin having a glycidyl group, acrylic resin having a carboxyl group / Resin having unsaturated bond, polyester resin / resin having unsaturated bond, polyester polyamide resin / resin having unsaturated bond, polyamide resin / resin having unsaturated bond, acrylic resin having amino group / having unsaturated bond Resin, resin having phenolic hydroxyl group / resin having unsaturated bond, acid anhydride resin / resin having unsaturated bond, acrylic resin / epoxy resin having carboxyl group and acrylic resin having glycidyl group, polyester resin / epoxy resin And grissy Acrylic resin having a hydroxyl group, polyester polyamide resin / epoxy resin and acrylic resin having a glycidyl group, polyamide resin / epoxy resin and acrylic resin having a glycidyl group, acrylic resin / epoxy resin having an amino group and acrylic resin having a glycidyl group Resin having a phenolic hydroxyl group / epoxy resin and acrylic resin having a glycidyl group, acid anhydride resin / epoxy resin and acrylic resin having a glycidyl group, polyamide resin / polyester resin, polyester resin / acid anhydride resin, urethane resin / Acrylic resin, urethane resin /
Examples include polyol-based resins, urethane resins / polyamide resins, and the like.

Among these, in consideration of the cured film strength, the resin used for either the powder coating A or the powder coating B is an acrylic resin having a carboxyl group, a polyester resin, a polyester polyamide resin, a polyamide resin, an amino resin. One or more resins selected from the group consisting of an acrylic resin having a group, a resin having a phenolic hydroxyl group and an acid-based resin, and the other resin is an epoxy resin, an acrylic resin having a glycidyl group, and an unsaturated bond. It is preferably at least one resin selected from the group consisting of resins having In this case, the polyester polyamide resin and the polyamide resin more preferably have an amino group or a carboxyl group at a terminal. The method for producing the resin is not particularly limited, and the resin can be produced by an ordinary method.

In this embodiment, when a resin is used in the above combination, a curing agent is not particularly required, but a curing agent may be used if necessary. In this case, as the curing agent to be used, conventionally known various curing agents can be used without any particular limitation, but the combination of the resin and the curing agent to be blended in the same powder coating material is singular. In this case, it is necessary to select appropriately so as not to be cured at 250 ° C. or lower.

That is, in the present invention, the powder coating A,
The resins in B are denoted as resin a and resin b, respectively,
When a curing agent that reacts with but does not react with the resin b is indicated as a curing agent a ′, and a curing agent that reacts with the resin b but does not react with the resin a is indicated as a curing agent b ′, the curing agent with the resin in the powder coating is cured. As for the combination of agents, it is necessary to select a resin and a curing agent such that powder coating A = resin a + curing agent b ′ powder coating B = resin b + curing agent a ′. This is an embodiment in which a curing agent suitable for each resin used in each powder coating is added to the other powder coating. Thus, in the powder coating, the resin in the same powder coating is different from the resin in the same powder coating. By using a non-reactive curing agent, a powder coating that does not thermoset at 250 ° C. or lower alone can be prepared.

As another embodiment in which a curing agent is used, an embodiment in which the curing agent is used only in one of the powder coatings as shown below may be used. Powder coating A = Resin a Powder coating B = Resin b + Curing agent a ′ In this embodiment, the curing reaction proceeds by the respective reactions of Resin a and Resin b and Resin a and Curing agent a ′. .

In the present invention, the reaction is carried out at 250 ° C.
Examples of a combination of a resin and a curing agent capable of causing a curing reaction below (for example, resin a <curing agent a ′> or resin b <curing agent b ′>) include, for example, organopolysiloxane <aminoxysilane>, organopolysiloxane Siloxane <alkoxysilane compound>, silicone polymer <tin compound>, polysulfide polymer <lead dioxide>, urethane resin <acrylic oligomer>, urethane resin <polyol compound>, urethane prepolymer <polyol compound>, polyester resin <polyepoxy compound> , Polyester resin <polyanhydride compound>, polyester resin <polyamine compound>, polyester resin <melamine compound>, polyester resin having a hydroxyl group at terminal <alkoxy compound>, polyester resin having carboxyl group <triglycidyl iso Cyanurate (hereinafter, TGI
Abbreviated as C. )>, A polyester resin having a terminal amino group <TGIC>, a polyester resin having a terminal amino group <modified melamine compound>, a polyester resin having a phenolic hydroxyl group <TGIC>, and a polyester resin having a terminal other than phenolic hydroxyl group. Saturated polyester resin <melamine compound>, polyester resin having a hydroxyl group other than phenolic terminal <2,4,6-triaminopyridine>, epoxy resin <polyamine compound>, epoxy resin <polyanhydride compound>, epoxy resin < Diamine compound>, epoxy resin <2,4,6-triaminopyridine>, epoxy resin <polycarboxylic acid compound>, acrylic resin having glycidyl group <2,4,6-triaminopyridine>, acrylic having amino group Resin <TGI
C>, polyamide resin <polycarboxylic acid compound>, polyamide resin having amino group at terminal <TGIC>, polyester polyamide resin <polycarboxylic acid compound>, polyester polyamide resin <TGIC>, novolak resin <TGIC>, alkoxy resin < Polyol compound>
And the like. Here, examples of the diamine compound include adipic dihydrazide.

Accordingly, specific examples of the combination of the resin and the curing agent in the powder coatings A and B include, for example, the combinations shown in Table 1, but are not limited thereto.

[0028]

[Table 1]

The amount of the curing agent used in the present invention may be an amount necessary for a usual thermosetting reaction, and depends on the amount of the functional group present in the resin. Is preferably in the range of 0.8 to 1.2.

(2) Embodiment in which curing reaction does not occur at 250 ° C. or lower only with resin and resin As described above, in this embodiment, only resin and resin do not cause a curing reaction at 250 ° C. or lower even when melt-mixed. However, when a curing agent is used in combination, the mixture is melt-mixed to cause a curing reaction at 250 ° C. or lower.

Therefore, when the powder coating used in this embodiment is indicated as powder coating C and powder coating D, respectively, the resin used for powder coating C and the resin used for powder coating D are It is necessary to select a resin that does not cause a curing reaction at 250 ° C. or lower even if the resin is melt-mixed.

That is, in this embodiment, the powder coating C
And the resin used for the powder coating material D is indicated as resin c and resin d, respectively (however, the resin c and the resin d have a relationship that no curing reaction occurs at 250 ° C. or less even when melted and mixed). When a curing agent that reacts with but does not react with the resin d is indicated as a curing agent c ′, and a curing agent that reacts with the resin d but does not react with the resin c is indicated as a curing agent d ′, the curing agent with the resin in the powder coating is cured. As for the combination of agents, it is necessary to select a resin and a curing agent such that powder coating C = resin c + curing agent d ′ powder coating D = resin d + curing agent c ′. This is an embodiment in which a curing agent suitable for each resin used in each powder coating is added to the other powder coating. Thus, in the powder coating, the resin in the same powder coating is different from the resin in the same powder coating. By using a non-reactive curing agent, a powder coating that does not thermoset at 250 ° C. or lower alone can be prepared.

The combination of the resin and the curing agent in the powder coatings C and D which can react with each other to cause a curing reaction at 250 ° C. or lower is not particularly limited as long as it has the above-described relationship.

Accordingly, specific examples of the combination of the resin and the curing agent in the powder coatings C and D include, for example, the combinations shown in Table 2, but are not limited thereto.

[0035]

[Table 2]

In the combination of the epoxy resin and the polyester resin, depending on the type of the functional group of the polyester resin, as described above, in addition to the combination capable of causing a curing reaction between the resins, as shown in Table 2,
Some combinations can cause a curing reaction by using a curing agent in combination.

As described above, in the powder coating material of the present invention, in addition to the resin, a curing agent appropriately selected according to each embodiment can be used. And various additives can also be used.

As the coloring agent used in the present invention, conventionally known coloring agents can be used without any particular limitation, and are appropriately selected according to the color tone of the powder coating. For example, titanium oxide, carmine 6B, carbon black, copper phthalocyanine, acetoacetic acid arylamide-based monoazo yellow pigment, disazo yellow, pigment red and the like can be mentioned. The amount used is preferably about 5 to 60 parts by weight based on 100 parts by weight of the resin.

The additives used as necessary in the present invention can be used without any particular limitation as far as they are conventionally used in coating compositions. Examples thereof include a spreading agent such as an acrylate polymer, a crosslinking accelerator such as various catalysts and organic tin compounds, and a pinhole inhibitor such as benzoin. These additives are
It is preferable to use about 0.1 to 5 parts by weight for each 100 parts by weight of the resin.

To prepare the powder coating of the present invention, first,
The above various components are melt-kneaded by an extruder or the like. After cooling, for example, physical pulverization is performed using a pulverizing device such as a hammer mill and a jet impact mill, and then an air classifier, and a desired average particle size is obtained by using a classifier such as a micron classifier. Can be obtained. Further, a fluidity modifier such as silica, alumina, titania, or zirconia may be added to the powder surface.

The average particle diameter of the powder coating of the present invention is 1 μm in order to prevent agglomeration and to uniformly mix two or more powder coatings.
m or more, preferably 5 μm or more,
Further, in order to prevent the film thickness of the obtained coating film from becoming too large, it is desirable that the thickness be 50 μm or less, preferably 30 μm or less. Here, the average particle diameter can be measured by the Coulter counter method. In addition, there is no problem even if it is 20 to 50 μm in order to melt and homogenize at the time of mixing and coating.

By using the above-described powder coating composition of the present invention in combination, a coating film having a uniform hue can be obtained.

Next, a more preferred embodiment of the combination of the powder coatings of the present invention will be described from the viewpoint of melt viscosity.

In the present invention, when the powder coatings of the present invention are used in combination, the melting of each powder coating at a temperature of 90% of the curing start temperature of a mixture of two or more powder coatings having different hues. The difference in viscosity is desirably within 20 pa · s, preferably within 15 pa · s, more preferably within 10 pa · s from the viewpoint of the gloss and strength of the coating film. That is, for example, when three types of powder coatings A, B, and C are used in combination, the difference in melt viscosity at a temperature of 90% of the curing start temperature between AB, BC, and AC is within 20 pa · s. Preferably, there is.

In the present invention, the curing start temperature of the powder coating mixture can be determined from the rise of the exothermic peak measured when the temperature is raised at 10 ° C./min using a differential scanning calorimeter.

In the present invention, the melt viscosity of the powder coating is
Under the following measurement conditions, it can be measured using an RDA-II dynamic analyzer (manufactured by Rheometrics).

[Measurement conditions] Geometry: Parallel plate (radius 12.5 mm) Frequency: 62.8 rad / sec Distortion: 2%

In the present invention, examples of a method for adjusting the melt viscosity of the powder coating include a general method for adjusting the melt viscosity of the resin. Adjustment of the melt viscosity of the resin, for example,
It can be performed by adjusting the skeleton, molecular weight, molecular weight distribution, degree of cross-linking, etc. of the resin. The melt viscosity of the powder coating is
It can also be adjusted by adding a filler or the like.

The curing temperature of the mixture of two or more kinds of powder coatings combined according to the present invention is less than 250 ° C., preferably 2 ° C., from the viewpoint of the risk of thermal decomposition and economy.
It is desirable that the temperature is 30 ° C. or lower, more preferably 200 ° C. or lower.

In the present invention, the curing temperature is calculated from the temperature of the exothermic peak top measured when the temperature is increased at 10 ° C./min using a differential scanning calorimeter (DSC220, manufactured by Seiko Instruments Inc.). can do.

As described above, powder coatings can be combined. In the present invention, a powder coating composition in which two or more of the above powder coatings are mixed in advance is provided. That is, it is a powder coating composition containing two or more kinds of powder coatings having different hues, each of which is used alone at 250 ° C.
It is a powder coating composition comprising two or more powder coatings, which do not thermally cure in the following, but have the property of forming a coating film having a uniform hue by being thermally cured by mixing and coating two or more.

In the combination of resin and resin in the powder coating in the powder coating composition, the same combination of resins as described above is blended. Among them, one resin is selected from the group consisting of an acrylic resin having a carboxyl group, a polyester resin, a polyester polyamide resin, a polyamide resin, an acrylic resin having an amino group, a resin having a phenolic hydroxyl group, and an acid-based resin. The above resin is preferable, and the other resin is at least one resin selected from the group consisting of an epoxy resin, an acrylic resin having a glycidyl group, and a resin having an unsaturated bond. In addition, when using a curing agent together with a resin, the above-described combinations are similarly applied.

When mixing two or more powder coatings,
The mixing ratio and the like are appropriately selected depending on the intended hue. As a method for preparing the powder coating composition by mixing the powder coating, a conventionally known method such as a method of dry-mixing each powder coating with a high-speed stirrer such as a Henschel mixer or a super mixer is used. It is possible.

Each of the powder coatings of the present invention alone has 2
Although it does not thermoset at 50 ° C. or less, it is thermoset by mixing and coating two or more types. That is, at the time of baking and curing, the respective powder coatings are melted and sufficiently hardened after being uniformly mixed, so that a coating film having a uniform hue can be obtained. In addition, the powder coating composition of the present invention contains two or more powder coatings having the above-mentioned properties, so that the powder coating composition is melted during baking and hardened to form a uniform state. , It is possible to obtain a coating film having a uniform hue.

The feature of the present invention is that each powder coating alone is 2
It is adjusted so as not to be thermally cured at 50 ° C. or lower. Conventionally known powder coatings,
Since it causes thermal curing at 250 ° C or less, if two or more powder coatings are mixed and applied, the resin used for each powder coating will quickly cure with melting at the time of baking, and the two The powder paints described above do not mix to form a uniform state. As a result, the state after curing is such that the particles of each powder coating can be clearly seen, and the resulting coating film does not have a uniform hue.

On the other hand, in the embodiment of the present invention which does not require a curing agent, the resin used for each powder coating does not cure by itself at 250 ° C. or lower, but two or more powder coatings are used. By mixing and applying, the resin and resin used in each powder coating melt at the time of baking, and only when uniformly mixed do one resin act as a curing agent for the other resin. As a result, the resulting coating film has a uniform hue.

On the other hand, in a mode using a curing agent, a resin and a curing agent which are mixed in the same powder coating material are selected so as not to react with each other. Therefore, the powder coating alone does not cure, and two or more powder coatings are melted and mixed at the time of baking, whereby a curing reaction occurs due to the action of the curing agent in the powder coating on the other side, and the resulting coating is obtained. The film has a uniform hue. This is because the curing agent that reacts with the resin used is compounded in the powder coating on the other side, so unlike the conventional technology mixed in the same powder coating, the start of the curing reaction is delayed by that much. However, it is presumed that a curing reaction occurs after the resin is uniformly melted and mixed.

The powder coating composition and the powder coating composition of the present invention are used in a coating method for obtaining a coating film having a uniform hue by mixing and applying two or more powder coatings having different hues.

In the present invention, “mixed coating” means that two or more powder coatings are mixed and applied. The term “coating” as used herein refers to a series of processes for forming a coating film through a baking process at 100 to 200 ° C. after coating the object by various methods as described below.
Regarding the “coating” of the powder coating composition in the present invention,
It has the same meaning.

When two or more powder coatings are mixed and applied, two or more powder coatings may be mixed in advance, or two or more powder coatings may be mixed using an electron gun or the like. The paint may be applied while being mixed at the time of application. Here, as a method of previously mixing the powder coating, a conventionally known method such as a method of dry-mixing each powder coating with a high-speed stirrer such as a Henschel mixer or a super mixer can be used.

The means for coating is not particularly limited, but includes, for example, a coating method using an electrostatic spray, a fluid immersion method, a plastic spraying method, and a pro-vac method.

As described above, according to the present invention, a coating film having a uniform hue can be provided because, as a result of being melted by heat during baking, they are uniformly mixed and thermally cured. In the present invention, since a uniform hue is obtained by such an action mechanism, a uniform hue is obtained even if the particle size of the powder coating is larger than 20 μm.

The coatings and coated articles obtained using the powder coating of the present invention, or using the powder coating composition of the present invention or two or more powder coatings combined according to the present invention, It has a uniform hue.

[0064]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention.

Resin Production Example 1 750 g of ethylene oxide adduct of bisphenol A
(2 moles) and 438.6 g (3 moles) of adipic acid were placed in a 3 liter four-necked flask equipped with a thermometer, a stainless steel stirring rod, a falling condenser, and a nitrogen inlet tube, and heated to 230 ° C. And reacted. Thereafter, 272.4 g (2 mol) of m-xylylenediamine was added to perform polyamideation.

The degree of polymerization was monitored from the softening point in accordance with ASTM E28-67. When the softening point reached 90 ° C., the reaction was terminated, and a polyester polyamide resin was obtained. The amine value of the obtained resin is 100 mgKOH / g
Met. The amine value is measured according to ASTM D2073-
66. This resin is referred to as binder resin A.

Resin Production Example 2 750 g of ethylene oxide adduct of bisphenol A
(2 moles), 166 g (1 mole) of terephthalic acid and 292.4 g (2 moles) of adipic acid were placed in a 3 liter four-necked flask equipped with a thermometer, a stainless steel stirring rod, a falling condenser and a nitrogen inlet tube. Then, the temperature was raised to 230 ° C. to cause a reaction. Thereafter, m-xylylenediamine 27
2.4 g (2 mol) was added to perform polyamide conversion.

The degree of polymerization was monitored from the softening point in accordance with ASTM E28-67. When the softening point reached 90 ° C., the reaction was terminated, and a polyester polyamide resin was obtained. The amine value of the obtained resin was 80 mgKOH / g. The amine value is measured according to ASTM D2073-6.
6 was measured. This resin is referred to as binder resin B.

Resin Production Example 3 Ethylene glycol 186 g (3 mol), neopentyl glycol 728 g (7 mol), terephthalic acid 1494
g (9 mol) and 192 g (1 mol) of trimellitic anhydride were placed in a 3 L four-necked flask equipped with a thermometer, a stainless steel stirring rod, a falling condenser, and a nitrogen inlet tube, and the temperature was raised to 220 ° C. And reacted.

The degree of polymerization was monitored from the softening point in accordance with ASTM E28-67. When the softening point reached 90 ° C., the reaction was terminated, and a polyester resin was obtained. The acid value of the obtained resin was 52.4 KOHmg / g. The acid value was measured according to JIS K0070. This resin is referred to as a binder resin C.

Resin Production Example 4 186 g (3 mol) of ethylene glycol, 728 g (7 mol) of neopentyl glycol, and terephthalic acid 1
743 g (10.5 mol) was placed in a 3 L four-necked flask equipped with a thermometer, a stainless steel stirrer, a falling condenser, and a nitrogen inlet tube, and heated to 220 ° C. for reaction.

The degree of polymerization was monitored from the softening point in accordance with ASTM E28-67. When the softening point reached 90 ° C., the reaction was terminated, and a polyester resin was obtained. The acid value of the obtained resin was 52.5 KOHmg / g. This resin is referred to as a binder resin D.

Production Example 1 of Powder Coatings 100 parts by weight of epoxy resin (manufactured by Mitsui Petrochemicals Co., Ltd., solid epoxy resin) 8 parts by weight of disazo yellow (manufactured by Dainichi Seika Co., Ltd., Pigment Yellow ECY-210) , Acronal 4F) 1 part by weight After the above composition was mixed well with a super mixer,
Knead using a bush kneader, cool and then mix
The powder was pulverized using an M pulverizer (manufactured by Nippon Pneumatic) to obtain a powder having an average particle size of 27 μm. 100 parts by weight of this powder was mixed with silica (Aerosil R9, manufactured by Nippon Aerosil Co., Ltd.).
72) 0.3 parts by weight was uniformly mixed using a Henschel mixer to obtain a powder coating (1).

Production Example 2 of Powder Coating Polyester polyamide resin (Binder resin A, amine value: 100 mg KOH / g) 100 parts by weight Carmine 6B (Sumitomo Chemical Co., Ltd., Sumika Print Carmine 6B) 8 parts by weight Flow-off agent ( 1 part by weight of Acronal 4F) manufactured by BASF In the same manner as in Production Example 1 of a powder coating, a powder having an average particle size of 29 μm was obtained from the above composition. Silica (Aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts by weight of this powder.
3 parts by weight were uniformly mixed using a Henschel mixer to obtain a powder coating (2).

Production Example 3 of Powder Coating Polyester polyamide resin (binder resin B, amine value: 80 mgKOH / g) 100 parts by weight Copper phthalocyanine (Cyanine Blue KRS, Sanyo Dyeing Co., Ltd.) 6 parts by weight Dispersant (BASF) Acronal 4F) 1 part by weight The above composition was treated in the same manner as in Powder Coating Production Example 1 to obtain a powder having an average particle size of 28 μm. Silica (Aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts by weight of this powder.
3 parts by weight were uniformly mixed using a Henschel mixer to obtain a powder coating (3).

Production Example 4 of Powder Coating Polyester resin (ER-8107, manufactured by Nippon Ester Co., Ltd., acid value: 32.5 mg KOH / g) 40 parts by weight Polyester resin (ER-8100, manufactured by Nippon Ester Co., acid value: 65.8 mg KOH) / g) 54 parts by weight TGIC (Ciba Geigy, Araldite PT810) 18 parts by weight Disazo Yellow (Daiichi Seika Co., Ltd., Pigment Yellow ECY-210) 8 parts by weight Dispersant (BASF, Acronal 4F) 1 part by weight benzoin 0.5 parts by weight A powder having an average particle diameter of 27 μm was obtained from the above composition in the same manner as in Production Example 1 for powder coating. Silica (Aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts by weight of this powder.
3 parts by weight were uniformly mixed using a Henschel mixer to obtain a powder coating (4).

Preparation Example 5 of Powder Coating Polyester resin (ER-8107, Nippon Ester Co., Ltd., acid value: 32.5 mg KOH / g) 40 parts by weight Polyester resin (ER-8100, Nippon Ester Co., Ltd., acid value: 65.8 mg KOH) / g) 54 parts by weight TGIC (Ciba Geigy, Araldite PT810) 18 parts by weight Carmine 6B (Sumitomo Chemical Co., Ltd., Sumika Print Carmine 6B) 8 parts by weight Dispersant (BASF, Acronal 4F) 1 part by weight benzoin 0.5 parts by weight A powder having an average particle size of 28 μm was obtained from the above composition in the same manner as in Production Example 1 for powder coatings. Silica (Aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts by weight of this powder.
3 parts by weight were uniformly mixed using a Henschel mixer to obtain a powder coating (5).

Production Example 6 of Powder Coating Polyester resin (ER-8107, manufactured by Nippon Ester Co., Ltd., acid value: 32.5 mg KOH / g) 40 parts by weight Polyester resin (ER-8100, manufactured by Nippon Ester Co., acid value: 65.8 mg KOH) / g) 54 parts by weight TGIC (Araldite PT810 manufactured by Ciba Geigy) 18 parts by weight Copper phthalocyanine (Cyanine Blue KRS manufactured by Sanyo Dyestuffs) 6 parts by weight Flow-off agent (Acronal 4F manufactured by BASF) 1 part by weight Benzoin 0.5 parts by weight Part The above composition was obtained in the same manner as in Powder Coating Production Example 1 to obtain a powder having an average particle size of 29 μm. Silica (Aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts by weight of this powder.
3 parts by weight were uniformly mixed using a Henschel mixer to obtain a powder coating (6).

Production Example 7 of Powder Coatings 100 parts by weight of epoxy resin (manufactured by Mitsui Petrochemical, solid epoxy resin) 39 parts by weight of melamine compound (Resimene 747 manufactured by Monsant) 8 parts by weight Flowing agent (Acronal 4F, manufactured by BASF) 1 part by weight A powder having an average particle diameter of 29 μm was obtained from the above composition in the same manner as in Production Example 1 for powder coatings. Silica (Aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts by weight of this powder.
3 parts by weight were uniformly mixed using a Henschel mixer to obtain a powder coating (7).

Production Example 8 of Powder Coating Polyester resin (ER-6620, manufactured by Nippon Ester Co., Ltd., acid value: 0.8 mg KOH / g, hydroxyl value: 42.9 mg KOH / g) 100 parts by weight Adipic dihydrazide 9 parts by weight Disazo yellow (large Pigment Yellow ECY-210, manufactured by Nissei Chemical Co., Ltd.) 8 parts by weight Flow-off agent (Acronal 4F, manufactured by BASF) 1 part by weight The above composition was powdered in the same manner as in Powder Coating Production Example 1 to give a powder having an average particle size of 28 μm. I got a body. Silica (Aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts by weight of this powder.
3 parts by weight were uniformly mixed using a Henschel mixer to obtain a powder coating (8).

Production Example 9 of Powder Coating 100 parts by weight of epoxy resin (manufactured by Yuka Shell, Epicoat 1044AF) 8 parts by weight of disazo yellow (manufactured by Dainichi Seika Co., Ltd., Pigment Yellow ECY-210) 4F) 1 part by weight The above composition was mixed well with a spar mixer, kneaded and cooled using a bush kneader, and then pulverized using a PJM pulverizer manufactured by Nippon Pneumatic Co., Ltd. to obtain an average particle size of 2 parts.
A powder of 5 μm was obtained. 100 parts by weight of this powder and 0.3 part by weight of silica (Aerosil R972 manufactured by Nippon Aerosil Co., Ltd.) were uniformly mixed with a Henschel mixer to obtain a powder coating (9).

Production Example 10 of Powder Coating Polyester resin (binder resin C) 100 parts by weight Carmine 6B (Sumitomo Chemical Co., Ltd., Sumika Print Carmine 6B) 8 parts by weight Flow-off agent (BASF Corporation, Acronal 4F) 1 Parts by weight The above composition was obtained in the same manner as in Powder Coating Production Example 9 to obtain a powder having an average particle size of 25 μm. 100 parts by weight of this powder and 0.3 parts of silica (Aerosil R972, manufactured by Nippon Aerosil Co., Ltd.)
The parts by weight were uniformly mixed with a Henschel mixer to obtain a powder coating (10).

Production Example 11 of Powder Coating Except that binder resin D was used as the polyester resin,
A powder having an average particle size of 28 μm was obtained in the same manner as in Production Example 10 of the powder coating. 100 parts by weight of this powder and 0.3 part by weight of silica (Aerosil R972 manufactured by Nippon Aerosil Co., Ltd.) were uniformly mixed with a Henschel mixer to obtain a powder coating material (11).

Production Example 12 of Powder Coating As a polyester resin, ER-8 manufactured by Nippon Ester Co., Ltd. was used.
Except for using 123, a powder having an average particle size of 28 μm was obtained in the same manner as in Production Example 10 of the powder coating. 100 parts by weight of this powder and silica (Aerosil R97 manufactured by Nippon Aerosil Co., Ltd.)
2) 0.3 parts by weight were uniformly mixed with a Henschel mixer to obtain a powder coating (12).

Example 1 50 parts by weight of the powder coating (1) and 50 parts by weight of the powder coating (2) were mixed using a Henschel mixer. The resulting mixture was applied to a degreased steel plate by electrostatic spraying, and then baked at 180 ° C. for 20 minutes to obtain a coating film. The obtained coating film was uniform vermilion.

Example 2 50 parts by weight of the powder coating (1) and 50 parts by weight of the powder coating (3) were mixed using a Henschel mixer. When a coating film was obtained from the obtained mixture in the same manner as in Example 1, the obtained coating film was uniform green.

Example 3 50 parts by weight of the powder coating (7) and 50 parts by weight of the powder coating (8) were mixed using a Henschel mixer. The obtained mixture was applied to a degreased steel plate by electrostatic spraying. Thereafter, the film was baked at 180 ° C. for 20 minutes to obtain a coating film. The obtained coating film was a uniform vermilion color.

Example 4 A powder coating composition was prepared by mixing 50 parts by weight of the powder coating (1) and 50 parts by weight of the powder coating (2) using a Henschel mixer. After storage for 6 months (at normal temperature / normal pressure / normal humidity), a steel plate degreased in the same manner as in Example 1 was applied by electrostatic spraying, and baked at 180 ° C. for 20 minutes to obtain a coating film. The coating film obtained in the same manner as in Example 1 was uniform vermilion.

Example 5 50 parts by weight of powder coating (9) and powder coating (10) 50
Parts by weight were mixed with a Henschel mixer. The curing start temperature of the obtained mixture was 167 ° C. The melt viscosities of the respective powder coatings at 150 ° C., which is 90% of the curing start temperature, were 5 pa · s and 15 pa · s, and the difference was 10 pa · s. The obtained mixture was applied to a degreased steel plate by electrostatic spraying, and then baked at 180 ° C. for 20 minutes to obtain a coating film. The obtained coating film was uniform vermilion.

The gloss and pencil strength of the obtained coating film were measured according to the following methods. As a result, the gloss is 76,
The pencil strength was 2H.

[Gloss] According to a method based on ASTM 3363-74, a gloss meter (manufactured by Minolta Camera Co., Ltd., G
M-60).

[Pencil strength] JIS K5400 8.4
It is measured according to the method according to the above.

Example 6 50 parts by weight of powder coating (9) and powder coating (11) 50
Parts by weight were mixed with a Henschel mixer. The curing start temperature of the obtained mixture was 167 ° C. The melt viscosities of the respective powder coatings at 150 ° C., which is 90% of the curing start temperature, were 5 pa · s and 11 pa · s, and the difference was 6 pa · s. The resulting mixture is applied to a degreased steel plate by electrostatic spraying.
Baking was performed at 80 ° C. for 20 minutes to obtain a coating film. The resulting coating is
It was a uniform vermilion color.

The gloss and pencil strength of the obtained coating film were measured in the same manner as in Example 5. As a result, the gloss is 8
2. The pencil strength was H.

Example 7 50 parts by weight of powder coating (9) and powder coating (12) 50
Parts by weight were mixed with a Henschel mixer. The curing start temperature of the obtained mixture was 167 ° C. The melt viscosities of the respective powder coatings at 150 ° C., which is 90% of the curing start temperature, were 5 pa · s and 34 pa · s, and the difference was 29 pa · s. The obtained mixture was applied to a degreased steel plate by electrostatic spraying. Thereafter, baking was performed at 180 ° C. for 20 minutes to obtain a coating film. The obtained coating film was uniform vermilion.

The gloss and pencil strength of the obtained coating film were measured in the same manner as in Example 5. As a result, the gloss is 5
0, the pencil strength was HB, and the gloss and the pencil strength were inferior to those of Examples 5 and 6.

Comparative Example 1 50 parts by weight of the powder coating (4) and 50 parts by weight of the powder coating (5) were mixed using a Henschel mixer. When a coating film was obtained from the obtained mixture in the same manner as in Example 1,
The resulting coating film was non-uniform vermilion.

Comparative Example 2 50 parts by weight of the powder coating (4) and 50 parts by weight of the powder coating (6) were mixed using a Henschel mixer. When a coating film was obtained from the obtained mixture in the same manner as in Example 1,
The resulting coating was uneven green.

As shown by the above results, in Comparative Examples 1 and 2 in which two types of powder coatings each containing a polyester resin were mixed and applied, each of the powder coatings was independently cured by heat, so that a coating having a uniform hue was applied. No film is obtained. In contrast, in Examples 1 to 7 in which a powder coating containing an epoxy resin and a powder coating containing a polyester polyamide resin or a polyester resin were mixed and applied, each of the powder coatings did not cause thermosetting alone. However, since each powder coating is melted during baking and hardened, and then heat-cured after being sufficiently mixed, a coating film having a uniform hue can be obtained. Further, even in Example 3 in which a resin and a curing agent are blended, a coating film having a uniform hue can be obtained. Further, the same applies to Example 4 using a composition containing two types of powder coatings. In Examples 5 and 6, the difference in melt viscosity at a temperature 90% of the curing start temperature of the powder coating mixture used was 20 p.
Since it is adjusted to be within a · s, a coating film which is more excellent in gloss and pencil strength than in Example 7 can be obtained.

[0100]

According to the present invention, by preparing powder coatings of several colors having different colors, coating films of all colors can be formed. It is no longer necessary to stock.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C09D 135/00 C09D 135/00 161/06 161/06 163/00 163/00 167/00 167/00 177/12 177/12 (72) Inventor Yukiya Sato 1334 Minato, Wakayama City Kao Corporation Research Laboratory (72) Inventor Shingo Tanaka 1-4-1 Nishi-ku, Noribori, Osaka City Kao Corporation Osaka Branch Office (58) Field surveyed (Int.Cl. ⁶ , DB name) C09D 5/03 C09D 7/14

Claims (14)

(57) [Claims] 1. A powder coating used in a coating method for obtaining a coating film having a uniform hue by mixing and coating two or more powder coatings having different hues, and is independently thermosetting at 250 ° C. or lower. A powder coating which has the property of being thermoset at 250 ° C. or less when mixed with another type of powder coating. 2. An acrylic resin having a carboxyl group,
Polyester resin, polyester polyamide resin, polyamide resin, acrylic resin having an amino group, resin having a phenolic hydroxyl group, and mixed with a powder coating containing at least one resin selected from the group consisting of acid anhydride resins. Wherein the powder coating contains at least one resin selected from the group consisting of an epoxy resin, an acrylic resin having a glycidyl group, and a resin having an unsaturated bond. The powder coating according to claim 1. 3. A powder coating mixed and applied with a powder coating containing at least one resin selected from the group consisting of an epoxy resin, an acrylic resin having a glycidyl group and a resin having an unsaturated bond. A powder selected from the group consisting of acrylic resins having carboxyl groups, polyester resins, polyester polyamide resins, polyamide resins, acrylic resins having amino groups, resins having phenolic hydroxyl groups, and acid anhydride resins. The powder coating according to claim 1, comprising the above resin. 4. An average particle size of 1 μm or more and 50 μm or less.
The powder coating according to any one of claims 1 to 3. 5. A method in which two or more powder coatings having different hues are used in combination, and each of them is used alone.
A method using a powder coating material which does not thermoset at 0 ° C. or lower, but has a property of forming a coating film having a uniform hue by thermosetting by mixing and coating two or more kinds. 6. A resin of a powder coating material having two different hues, wherein one resin has an acrylic resin, a polyester resin, a polyester polyamide resin having a carboxyl group,
A polyamide resin, an acrylic resin having an amino group, a resin having a phenolic hydroxyl group, and one or more resins selected from the group consisting of an acid-based resin, the other resin being an epoxy resin, an acrylic resin having a glycidyl group, and The powder coating according to claim 5, which is at least one resin selected from the group consisting of resins having an unsaturated bond.
How to use . 7. A powder coating further comprising a curing agent.
In the combination using, the curing agent is the same powder coating.
Does not react with the resin contained in the mixture,
Reacts with the resin blended in other powder coatings
The powder paint according to claim 5 or 6 is used in combination.
How to use. 8. The difference in the melt viscosity of the powder coating at 90% of the temperature of the curing initiation temperature of a mixture of different powder coatings of two or more hues, claim 5-7 is within 20 Pa · s
A method of using any of the powder coatings described above in combination. 9. A powder coating composition containing two or more kinds of powder coatings having different hues, each of which is 250 powder by itself.
A powder coating composition comprising two or more powder coatings having a property of not being thermosetting at a temperature of not more than 0 ° C., but having a property of forming a coating film having a uniform hue by mixing and coating two or more types. Stuff. 10. A resin of a powder coating material having two different hues, one of which is an acrylic resin having a carboxyl group, a polyester resin, a polyester polyamide resin, a polyamide resin, an acrylic resin having an amino group,
One or more resins selected from the group consisting of a resin having a phenolic hydroxyl group and an acid anhydride resin, and the other resin is an epoxy resin, an acrylic resin having a glycidyl group, and a resin having an unsaturated bond. The powder coating composition according to claim 9, which is at least one selected resin. 11. A coating method characterized in that a coating film having a uniform hue is provided by mixing and applying two or more of the powder coating materials according to any one of claims 1 to 4 . 12. A coating method characterized by providing a coating film of uniform color by mixing a combination of I <br/> Rikonatai paint method in accordance with claim 5-8 coated. 13. A coating method characterized by giving a coating film having a uniform hue by applying the powder coating composition according to claim 9 or 10 . 14. The method of claim 11 to 13 or homogeneous hue of the coating Sobutsu obtained by applying a coating method according.