JP2002155237A - Lubricating powder coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new solventless type and resource-saving lubricating powder coating composition with a small amount of volatile gases. SOLUTION: This lubricating powder coating composition is obtained by dry blending (A) a raw material powder coating with (B) a composite particle prepared by making an acrylic polymer fine powder having 0.1-2.0 μm mean particle diameter adhere through a binder to a lubricating polymer powder having 2-30 μm means particle diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a novel lubricating powder coating composition.

[0002]

2. Description of the Related Art Lubricating paints are used for maintenance-free whole-life lubrication of parts where lubricants cannot be used or general-purpose products.
It is a paint for forming a solid lubricating film to be used. Lubricating paints are usually used for precision equipment, drive units for OA equipment, etc., for example, shutter blades of cameras, zoom lens barrels,
It is applied to slide rails of printers.

[0003] As a conventional lubricating paint, an organic solvent type paint in which a lubricating polymer powder is dispersed in a solvent-soluble resin containing an organic solvent is mainly used, and this is spray-painted, dipped-painted, tumbled-painted. Thus, a coating film was formed by painting on an object to be coated. At this time, a large amount of the organic solvent was volatilized in the atmosphere.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a solvent-free, resource-saving, novel lubricating powder coating composition containing less volatile gas.

[0005]

Means for Solving the Problems As a result of earnest studies, the present inventors have found that the above object can be achieved by dry mixing specific composite particles into a powder coating, and based on this, the present invention is completed. Reached.

That is, the present invention relates to a raw material powder coating (A)
Composite particles (B) obtained by adhering an acrylic polymer fine powder having an average particle diameter of 0.1 to 2.0 μm to a lubricating polymer powder having an average particle diameter of 2 to 30 μm via a binder,
The present invention relates to a lubricating powder coating composition obtained by dry mixing.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The powder coating (A) used as a raw material in the present invention is not particularly limited, and a thermoplastic powder coating or a thermosetting powder coating can be widely used. It is preferable to use a thermosetting powder coating in terms of abrasion and the like.

As the thermosetting powder coating, for example, an epoxy powder coating obtained by adding an imidazole-based curing agent to an epoxy resin composed of epichlorohydrin and bisphenol A, and an epichlorohydrin and bisphenol A are conventionally used. Epoxy obtained by adding a polyester resin containing a terminal carboxylic acid to an epoxy resin as a curing agent
A polyester powder coating, a polyester powder coating obtained by adding a blocked isocyanate to a polyester resin as a curing agent, an acrylic powder coating obtained by adding a carboxylic acid-based curing agent to a glycidyl group-containing acrylic resin, and the like can be used.

The average particle diameter of the raw material powder coating material (A) can be usually about 10 to 70 μm.
If the thickness is less than 5 μm, the film thickness tends to be difficult to be formed.
If it is 0 μm or more, the smoothness tends to decrease.
Those having an average particle diameter of about 50 μm are desirable.

The composite particles (B) to be dry-mixed with the raw material powder coating (A) are prepared by adding a lubricating polymer powder having an average particle size of 2 to 30 μm via a binder to an average particle size of 0.1 to 2.0.
Acrylic polymer fine powder of μm is attached.

The lubricating polymer powder is a base particle of the composite particles. Examples of the polymer powder include polytetrafluoroethylene (PTFE), polyolefin,
Polyphenylene sulfide (PPS), polyamide (PA), polyimide (PI), polyamide imide (P
Powders such as AI) and polyetheretherketone (PEEK) can be used. The average particle diameter of the polymer powder is 2 to 30 μm. When the average particle diameter is less than 2 μm, the lubricating properties are reduced, and when the average particle diameter is more than 30 μm, the smoothness of the coating film is reduced, and both are not preferred.

The acrylic polymer fine powder is a child particle of the composite particle, and has a function of charging the base particle cationically or anionicly by attaching it to the lubricating polymer powder of the base particle. For example, if the base particles are to be cationically charged, the child particles may be cationically charged using a cationic polymerization initiator during the polymerization of the child particles, and if the base particles are to be anionically charged,
The child particles may be anionically charged using an anionic polymerization initiator during the polymerization of the child particles.

As the acrylic polymer fine powder, for example, polymethyl methacrylate and the like can be preferably used.
The average particle diameter is from 0.1 to 2.0 from the viewpoint of uniformly adhering to the particle surface of the lubricating polymer powder as the base particle.
μm. The average particle size is preferably from 0.1 to 1.
0 μm.

The acrylic polymer fine powder is attached to the lubricating polymer powder particles via a binder. As the binder at this time, for example, an acrylic copolymer such as a copolymer of ethyl acrylate and butyl acrylate, and ethylene oxide-modified polydimethylsiloxane can be suitably used.

The composite particles (B) are generally used in an amount of 0.2 to 5.0 binders per 100 parts by weight of the lubricating polymer powder.
It can be suitably prepared by attaching 5 to 20 parts by weight of the acrylic polymer fine powder via parts by weight. If the amount of the binder is less than 0.2 parts by weight, the adhesive force to the acrylic polymer fine powder which becomes the child particles becomes weak, and if it exceeds 5.0 parts by weight, the obtained composite particles are likely to adhere to each other. Are not preferred. When the amount of the acrylic polymer fine powder is less than 5 parts by weight, the charging characteristics are deteriorated, and when the amount exceeds 20 parts by weight, an excessive amount of the acrylic polymer fine powder remains as a single powder. Absent.

More specifically, the composite particles (B) can be prepared, for example, by adding a predetermined amount of a binder to a lubricating polymer powder serving as a base particle, and using a Henschel mixer, a ball mill, a pin disk mill or the like. Mix for about 60 minutes, apply the binder to the surface of the lubricating polymer powder, then add a predetermined amount of acrylic polymer fine powder that will become child particles, mix for about 3 to 60 minutes, and add By attaching child particles via a binder,
The composite particles (B) are suitably obtained. The composite particles (B) can also be suitably obtained by simultaneously adding a predetermined amount of a binder and a fine acrylic polymer powder to the lubricating polymer powder and mixing them in the same manner.

FIG. 1 shows a schematic view of the cross-sectional structure of the composite particle (B). In FIG. 1, 1 indicates a lubricating polymer powder, 2 indicates a binder, and 3 indicates an acrylic polymer fine powder. As shown in FIG. 1, the composite powder (B) is obtained by adhering an acrylic polymer fine powder to a lubricating polymer powder via a binder.

The lubricating powder coating composition of the present invention comprises the composite powder (B) 5 per 100 parts by weight of the raw powder coating (A).
It is preferably obtained by dry-mixing 〜50 parts by weight with, for example, a Henschel mixer, a drum blender, a ribbon blender or the like. If the composite particles (B) are less than 5 parts by weight, it is difficult to satisfy the lubrication performance of, for example, a coefficient of kinetic friction (μs) of 0.15 or less and a weight loss of 10 mg or less.
When the amount exceeds 0 parts by weight, the adhesion between layers when re-coating the obtained powder coating material is reduced, and neither is preferable.

When the powder coating composition of the present invention is a powder coating composition containing composite particles to which a cationically-charged acrylic polymer fine powder is adhered, for example, a corona-charged electrolytic fluidized powder may be used. Using a body electrostatic coating machine, a corona electrostatic spray gun, or the like, the paint particles are negatively charged when passing through the coating gun, and are powder-coated on the object to be coated. At this time, among the paint particles, the composite particles to which the cationically-charged acrylic polymer fine powder is adhered have a negative charge speed, and the coating is delayed, so that they are present at a high density on the surface layer of the coating film. become.

When the powder coating composition of the present invention is a powder coating composition containing composite particles to which anionic charged acrylic polymer fine powder is adhered, for example,
Using a tribomatic powder electrostatic coating machine of a triboelectric charging system or the like, the coating particles are positively charged when passing through the coating gun, and are powder-coated on the object to be coated. At this time, among the paint particles, the composite particles to which the anionic-charged acrylic polymer fine powder is attached have a slower rate of positive charge,
Since the coating is delayed, it is present at a high density in the surface layer of the coating film.

Here, the object to be coated, the coating thickness of the powder coating composition, the curing conditions after coating, and the like are the same as in the case of ordinary powder coatings.

The structure of a coating film obtained by applying and curing the coating composition of the present invention will be described with reference to schematic diagrams. FIG. 2 shows an untreated lubricating polymer powder in a powder coating as a raw material,
FIG. 3 is a schematic view of a cross section of a cured coating film of a mixed powder coating composition. FIG. 3 is a composite particle obtained by adhering an acrylic polymer fine powder to a lubricating polymer powder via a binder to a powder coating material serving as a raw material. FIG. 1 is a schematic diagram of a cross section of a cured coating film of a powder coating composition of the present invention mixed with (B). 2 and 3, 4 indicates a cured coating film, 5 indicates an untreated lubricating polymer powder, and 6 indicates a composite particle (B). In each figure, the upper part of the cured coating film 4 is the coating film surface side, and the lower part is the object side. 2 and 3 that the lubricating polymer powder is uniformly present in the cured coating film of the powder coating composition mixed with the untreated lubricating polymer powder,
In the cured coating film of the powder coating composition of the present invention mixed with the composite particles (B), the composite particles (B) containing the lubricating polymer powder may be present at a high density on the surface layer of the coating film. I understand.

[0023]

The present invention will now be described more specifically with reference to examples and comparative examples. In each case, parts and% are based on weight in principle.

Example 1 100 parts of "Epicoat 1004K" (epoxy resin, manufactured by Yuka Shell Epoxy Co., Ltd., trade name), "Cureazole C11Zazine" (imidazole-based curing agent, trade name, manufactured by Shikoku Chemicals Co., Ltd.) 0.5 parts, "Carbon MA-10
0 "(color pigment, manufactured by Mitsubishi Kasei Co., Ltd., trade name) (1.5 parts) was kneaded, heated and melted, pulverized and classified to obtain an average particle diameter of 23.
As a result, 102 parts of a black powder coating material having a thickness of μm was obtained.

Next, 18 parts of a lubricating polymer powder "Lubron L-2" (polytetrafluoroethylene, trade name, manufactured by Daikin Industries, Ltd.) having an average particle diameter of 4 μm, and cationically charged having an average particle diameter of 0.4 μm. Acrylic polymer fine powder “MP-2701” (polymethyl methacrylate,
2 parts by Soken Chemical Co., Ltd., trade name: Binder “BYK
-331 "(ethylene oxide-modified polydimethylsiloxane, Big Chemie Japan Co., Ltd., trade name)
0.04 parts were mixed with a Henschel mixer for 5 minutes,
20.04 parts of composite particles having an average particle diameter of 5 μm containing polytetrafluoroethylene as base particles were obtained.

To 102 parts of the black powder coating, 20.04 parts of the composite particles were added and mixed with a Henschel mixer for 5 minutes to form an epoxy black lubricating powder coating 122.04.
Got a part.

This coating material was applied to a mild steel plate by a corona charging type electrolytic fluidized powder electrostatic coating machine (manufactured by Mesac Co., Ltd.) and cured by heating at 200 ° C. for 10 minutes. The resulting cured coating film was a 20 μm-thick lubricating coating film with uniform and good smoothness.

Example 2 100 parts of "Yupika coat GV-700" (polyester resin, trade name, manufactured by Nippon Yupika Co., Ltd.), 100 parts of "Cleran U-
1 "(block isocyanate, manufactured by Bayer Japan K.K., trade name) 23 parts," Titanium R-930 "(colored pigment, manufactured by Ishihara Sangyo K.K., trade name) 36 parts," Todacolor KN-320 "(colored) 3 parts of a pigment (trade name, manufactured by Toda Kogyo Co., Ltd.) were kneaded, heated and melted, pulverized, and classified to obtain 162 parts of a gray powder coating material having an average particle diameter of 25 μm.

Next, 45 parts of a lubricating polymer powder "Lancowax PE-1500" (polyethylene, manufactured by Langer & Co., trade name) having an average particle diameter of 6 μm, an average particle diameter of 0.
5 parts of 5 μm anionic-charged acrylic polymer fine powder “MP-1000” (polymethyl methacrylate, manufactured by Soken Chemical Co., Ltd., trade name), binder “BYK-3”
31 "(ethylene oxide-modified polydimethylsiloxane, trade name, manufactured by Big Chemie Japan KK) is mixed for 15 minutes by two passes of a pin disc, and a composite having an average particle diameter of 7 μm using polyethylene wax as base particles is mixed. 51 parts of particles were obtained.

To 162 parts of the above-mentioned gray powder coating material, 51 parts of the above-mentioned composite particles were added and mixed with a Henschel mixer for 5 minutes to obtain 213 parts of a polyester-based gray lubricating powder coating material.

This coating material is applied to a mild steel plate by a tribomatic electrostatic coating machine “MT-R” (trade name, manufactured by Matsuo Sangyo Co., Ltd.).
And cured by heating at 200 ° C. for 10 minutes.
The obtained cured coating film was a 30 μm-thick lubricating coating film with uniform and good smoothness.

Comparative Example 1 "Epicoat 1004K" (epoxy resin, manufactured by Yuka Shell Epoxy Co., Ltd., trade name) 100 parts, "Curesol C11Zazine" (imidazole-based curing agent, trade name, manufactured by Shikoku Chemicals Co., Ltd.) 0.5 parts and "Carbon MA-10"
0 "(color pigment, manufactured by Mitsubishi Kasei Co., Ltd., trade name) (1.5 parts) was kneaded, heated and melted, pulverized and classified to obtain an average particle diameter of 23.
As a result, 102 parts of a black powder coating material having a thickness of μm was obtained.

To 102 parts of the above black powder coating material, 18 parts of lubricating polymer powder "Rublon L-2" (polytetrafluoroethylene, manufactured by Daikin Industries, Ltd., trade name) having an average particle diameter of 4 μm was added, and a Henschel mixer was added. For 5 minutes to obtain 120 parts of an epoxy black lubricating powder coating material.

This coating material was applied to a mild steel plate by a corona charging type electrolytic fluidized powder electrostatic coating machine (manufactured by Mesac Co., Ltd.), and was cured by heating at 200 ° C. for 10 minutes. The obtained cured coating film was a black coating film having a uniform thickness and good smoothness with a thickness of 20 μm.

Comparative Example 2 100 parts of "Yupika coat GV-700" (polyester resin, trade name, manufactured by Nippon Yupika Co., Ltd.), "Cleran U-
1 "(block isocyanate, manufactured by Bayer Japan K.K., trade name) 23 parts," Titanium R-930 "(colored pigment, manufactured by Ishihara Sangyo K.K., trade name) 36 parts," Todacolor KN-320 "(colored) 3 parts of a pigment (trade name, manufactured by Toda Kogyo Co., Ltd.) were kneaded, heated and melted, pulverized, and classified to obtain 162 parts of a gray powder coating material having an average particle diameter of 25 μm.

Next, 162 parts of the above-mentioned gray powder coating material was coated with a lubricating polymer powder having an average particle diameter of 6 μm “Lancowax P”.
E-1500 "(polyethylene, manufactured by Langer & Co., trade name) (45 parts) was added and mixed with a Henschel mixer for 5 minutes to obtain 207 parts of a polyester-based gray lubricating powder coating material.

This coating material was applied to a mild steel plate by using a tribomatic electrostatic coating machine “MT-R” (trade name, manufactured by Matsuo Sangyo Co., Ltd.).
And cured by heating at 200 ° C. for 10 minutes.
The obtained cured coating film was a gray coating film having a uniform thickness and a good smoothness with a thickness of 30 μm.

Comparative Example 3 50% organic solvent (cyclohexanone / butyl acetate / xylene = 30/30/40 (weight ratio)) solution of "Epicoat 1004" (epoxy resin, trade name, manufactured by Yuka Shell Epoxy Co., Ltd.) 100 parts, "Hitanol 4020"
60% organic solvent (isobutanol / n-butanol /
Xylene = 60/20/20 (weight ratio)) solution (phenol resin, manufactured by Hitachi Chemical Co., Ltd., trade name) 500 parts,
50 parts of "Carbon FW-200" (color pigment, manufactured by Degussa Japan Co., Ltd., trade name), lubricating polymer powder "Lubron L-2" having an average particle diameter of 4 [mu] m (polytetrafluoroethylene, manufactured by Daikin Industries, Ltd.) , Product name) 300 copies,
500 parts of methyl isobutyl ketone, 150 parts of isopropyl alcohol and 150 parts of ethyl acetate were mixed and dispersed by an attritor mill for 200 minutes to obtain 1,750 parts of an organic solvent type black lubricating paint.

To 100 parts of the coating material, 50 parts of a special thinner having a composition (weight ratio) of ethyl acetate / methyl isobutyl ketone / xylene / toluene / cyclohexane = 15/15/35/30/5 was added, and spray-painted on a mild steel plate. And 1
It was cured by heating at 80 ° C. for 40 minutes. The obtained cured coating film was a lubricating coating film having a uniform thickness and good smoothness with a thickness of 15 μm.

Next, the lubricating coating films obtained in Examples and Comparative Examples were tested for (1) dynamic friction coefficient, (2) loss on wear, and (3) solvent volatilization according to the following methods. .

(1) The coefficient of dynamic friction is expressed as a coefficient (μs) measured using a reciprocating slide type dynamic friction coefficient measuring device (manufactured by Copal Co., Ltd.) at a load of 0.49 N and a slide frequency of 100 times / min. did.

(2) The weight loss was measured using a Taber type wear tester (manufactured by Tester Sangyo Co., Ltd.) with a load of 4.9.
N, wear wheel CS-10, wear loss at 1000 revolutions (m
g).

(3) Regarding the amount of solvent volatilization, the change in weight of the coated film before and after curing was measured, and the volatilization amount was calculated by the formula [(coating weight−dry coating weight) / (coating weight)] × 100. %) Was calculated.

The test results are shown in Table 1.

[0045]

[Table 1]

From Table 1, it is apparent that the lubricating coating film obtained from the coating composition of the present invention has no volatilization of the organic solvent and has extremely excellent lubricating performance.

[0047]

Industrial Applicability The lubricating powder coating composition of the present invention is a solvent-free powder coating containing less volatile gas and is a resource-saving powder coating. Further, the lubricating powder coating composition of the present invention, the acrylic polymer fine powder adhered via a binder, the lubricating polymer powder is uniformly dispersed, excellent in the smoothness of the coating film, further, Since the lubricating polymer powder concentrates on the surface of the coating film to form a cured coating film, it can exhibit lubricating properties equal to or better than that of a conventional organic solvent type lubricating coating material.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a cross-sectional structure of a composite particle (B).

FIG. 2 is a schematic diagram of a cross section of a cured coating film of a powder coating composition in which an untreated lubricating polymer powder is mixed with a powder coating.

FIG. 3 is a schematic view of a cross section of a cured coating film of the powder coating composition of the present invention in which the composite particles (B) are mixed with the powder coating.

[Explanation of symbols]

 1: Lubricant polymer powder 2: Binder 3: Acrylic polymer fine powder 4: Cured coating film 5: Untreated lubricious polymer powder 6: Composite particles (B)

Claims (3)

[Claims] The raw material powder coating material (A) has an average particle diameter of 2 to 3
A lubricating powder coating composition obtained by dry-mixing composite particles (B) obtained by adhering an acrylic polymer fine powder having an average particle diameter of 0.1 to 2.0 µm to a 0 µm lubricating polymer powder via a binder. object. 2. The composite particles (B) are composed of a lubricating polymer powder 1
2. The coating composition according to claim 1, wherein 5 to 20 parts by weight of an acrylic polymer fine powder is adhered to 00 parts by weight via a binder of 0.2 to 5.0 parts by weight. 3. The coating composition according to claim 1, wherein 5 to 50 parts by weight of the composite particles (B) are mixed with 100 parts by weight of the raw material powder coating (A).