JP2009155461A - Powder paint and electronic equipment casing - Google Patents

Abstract

Disclosed are a powder coating material and an electronic device casing that can realize stable coating and exhibit antibacterial properties without reducing the amount of antibacterial agent added and without increasing the number of manufacturing steps.
A first resin, a second resin, and an antibacterial agent are included, the antibacterial agent is unevenly distributed in the first resin, and the first resin and the second resin are out of phase. A powder coating material, wherein the first resin is in the form of particles and dispersed in the second resin. An embodiment in which the average particle diameter of the first resin dispersed in the second resin is 1 μm to 10 μm is preferable.
[Selection figure] None

Description

  The present invention relates to a powder coating material and an electronic device casing on which a coating film made of the powder coating material is formed.

  In recent years, titanium oxide has been used as an antibacterial agent, bactericidal agent, deodorizing agent, environmental purification agent, etc., utilizing the photocatalytic function (oxidative decomposition function) of titanium oxide. However, since titanium oxide itself does not have an ability to adsorb organic substances on its surface, there is a limit to the oxidative decomposition function obtained.

  Recently, research and development of products that can effectively bring out the characteristics of a combination of a semiconductor material such as titanium oxide and a calcium phosphate compound such as calcium hydroxyapatite have been carried out (for example, patents). Reference 1 and 2).

Further, calcium / titanium hydroxyapatite Ca ₉ Ti (PO ₄ ) ₆ (OH) ₂ having a photocatalytic function has been developed by exchanging a part of calcium ions in the apatite with titanium ions (for example, patents). Reference 3-6). Thereby, it has a photocatalytic function equivalent to that of titanium oxide, and further, the efficiency of the photocatalytic function can be improved by the specific adsorption property of the apatite.

  In addition, paints that can be mixed with antibacterial agents are roughly divided into three types: organic solvent-type paints, water-based emulsion-type paints, and powder paints. Currently, organic solvent-type paints are useful in terms of workability and durability. Therefore, it is considered that the spread of powder coating materials, which are considered to be the coating materials with the smallest environmental load, is promoted for the reasons described later.

  The organic solvent-type paint and the aqueous emulsion-type paint contain VOC (Volatile Organic Compounds), but since no solvent is used in the powder paint, VOC-less can be achieved.

  A conventional antibacterial agent-containing powder coating is composed of an antibacterial agent, a resin, a colorant, a charge control agent, and the like, and an antibacterial agent (antibacterial inorganic particles) 31 is dispersed in the coating film (resin) 30 (FIG. 3). ). Accordingly, when coating is performed using a conventional powder coating material, the antibacterial agent 31 is scattered almost evenly in the coating film 30, and the antibacterial agent 31 that is not present in the vicinity of the coating film surface can exert its function. There wasn't. Moreover, since the antibacterial agent 31 is more expensive than other constituent materials, there has been a problem of reducing the addition amount as much as possible.

  Therefore, in order to solve the above-mentioned problem, firstly, coating is performed using a powder coating containing no antibacterial agent, and after forming a coating film, coating is performed using a powder coating containing an antibacterial agent. It is conceivable that the antibacterial agent is unevenly distributed in the vicinity of the coating film surface by a painting method. However, in this case, there is a problem that the coating is performed twice, and the man-hour and cost cannot be reduced.

  Therefore, in order to solve the above problems, a powder coating containing no antibacterial agent and a powder coating containing an antibacterial agent are mixed, and the antibacterial agent is applied by one coating using the difference in resin viscosity. Although it has been disclosed that the layer made of the resin contained can be applied to the upper layer of the layer made of the resin not containing the antibacterial agent (paragraph [0030] in Patent Document 9), the following problems occur.

  In two types of powder paints with different compositions, the chargeability cannot be matched equally. Therefore, in the powder paint coating based on the powder chargeability, in the powder paint coating, depending on the mixing ratio There is a problem that two types of powder paints are not applied. For example, in two types of powder paints with a mixing ratio of 50:50, the chargeability of either one of the powder paints is increased, so that the powder paint with higher chargeability is applied more.

  In addition, since the chargeability is easily affected by humidity, and the manner in which humidity is affected varies depending on the composition of the paint, when two types of powder paints having different compositions are mixed, the humidity changes, The coating ratio of the powder paint will fluctuate.

  Furthermore, in order to realize antibacterial properties, there are the following problems.

  The calcium-titanium hydroxyapatite has a light energy required to excite the photocatalyst of 3.2 eV, which is approximately 380 nm when converted to the wavelength of light. Therefore, when calcium / titanium hydroxyapatite is used in antibacterial paints, it can exhibit antibacterial properties due to its photocatalytic function under ultraviolet light, but it is antibacterial in dark places and indoors under fluorescent lamps where there is almost no ultraviolet light. I can't show my sexuality. Therefore, an antibacterial paint using calcium / titanium hydroxyapatite is not used as a means for imparting antibacterial properties to electronic equipment casings and the like mainly used indoors.

Japanese Patent Laid-Open No. 2003-80078 JP 2003-321313 A JP 2000-327315 A JP 2001-302220 A JP 2003-175338 A Japanese Patent Laid-Open No. 2003-334883 JP-A-8-165216 JP-A-9-132502 Japanese Patent Laid-Open No. 10-324824

An object of the present invention is to solve the conventional problems and achieve the following objects.
That is, the present invention provides a powder coating material and an electronic device casing capable of realizing stable coating and exhibiting antibacterial properties without increasing the amount of antibacterial agent added and without increasing the number of manufacturing steps. The purpose is to do.

Means for solving the above-described problems are as listed in the appendix to be described later. That is,
The powder coating of the present invention includes a first resin, a second resin, and an antibacterial agent, and the antibacterial agent is unevenly distributed in the first resin, and the first resin and the second resin Are incompatible with each other, and the first resin is particulate and dispersed in the second resin.

  In the powder coating, the first resin (resin A10) is unevenly distributed with antibacterial agents and is incompatible with the second resin (resin B11), and the resin A10 is in the form of particles and dispersed in the resin B11. Therefore, when the powder coating material is heated and melted on the material to be coated, the molten resin A10 is dispersed in the molten resin B11 in the form of particles (FIG. 1A). When the curing is started, the uncured resin A10 is extruded (FIG. 1B). After the resin B11 is cured, the curing of the resin A10 is started (FIGS. 1C and D), and the antibacterial layer is formed on the layer made of the resin B11. A layer made of resin A10 in which agent (antibacterial inorganic particles) 12 is unevenly distributed is formed (FIG. 1E). Here, the direction in which the resin A10 is extruded is determined by the affinity of the resin A10 and the resin B11 with respect to the material to be coated (for example, an electronic device casing). For example, the affinity of the resin B11 with respect to the material to be coated is When the affinity for the material to be coated is higher, the resin A10 can be extruded in a direction away from the material to be coated (from the surface direction to the side surface direction of the coating film formed by the powder coating material).

  The electronic device casing of the present invention has an electronic device casing main body and a coating film formed on the outer surface of the electronic device casing main body and made of a powder coating, and the powder coating is a first resin. And a second resin and an antibacterial agent, the antibacterial agent is unevenly distributed in the first resin, the first resin and the second resin are incompatible, and the first resin The resin is particulate and dispersed in the second resin.

  In the electronic device casing, since the coating film made of the powder coating is formed on the outer surface of the electronic device casing main body, the amount of antibacterial agent added is reduced, and the manufacturing process is not increased and stable. Can be applied and can exhibit antibacterial properties.

According to the present invention, conventional problems can be solved, and the above object can be achieved.
According to the present invention, since the coating is performed using the powder coating composed of resin particles having the same composition, even when the humidity environment at the time of coating varies, stable coating (stability of coating thickness and two layers) A powder coating that can reduce the amount of antibacterial agent added and also exhibit antibacterial properties by making the antibacterial agent unevenly distributed on the coating surface. An electronic device housing can be provided.

(Powder paint)
The powder coating material of the present invention contains a first resin (resin A), a second resin (resin B), and an antibacterial agent, and further contains other components as necessary. Become.

  Moreover, it is preferable that the average particle diameter of the said powder coating material is 10-100 micrometers, and the powder with an average particle diameter of 5 micrometers or less is 5 mass% or less. When the average particle diameter of the powder coating material is less than 10 μm, the powder coating material is a mixture of two types of resins (resin A and resin B). The charge distribution of the powder coating is widened and a large amount of powder coating that is not applied is generated. On the other hand, when the average particle size of the powder coating exceeds 100 μm, stable coating by spraying becomes difficult. In addition, the average particle diameter of the powder coating was measured using a Coulter Multisizer (manufactured by Nikka Kisha Co., Ltd.).

  Furthermore, when the resin A is an acrylic resin and the resin B is an epoxy resin, formation of a two-layer coating film can be easily realized.

<Production method of powder paint>
In order to manufacture the powder coating material of the present invention, for example, a powder coating composition composed of resin A, resin B, and antibacterial agent is dry-mixed using a mixer or a blender, and then kneaded. Melt and knead and cool. Next, after pulverization using a mechanical or airflow type pulverizer, particles of the powder coating material can be obtained by classification.

<Resin A>
The resin A is not particularly limited as long as the antibacterial agent is unevenly distributed and is incompatible with the resin B, and can be appropriately selected according to the purpose. Resins such as epoxy resin, acrylic resin, phenol resin, xylene resin, urea resin, melanin resin, polyester resin, polyethylene resin, silicone resin, polyurethane resin, and polyamide resin can be used. When the main component of the resin A is a thermosetting resin, it is preferable to use a curing agent having a functional group capable of undergoing a crosslinking reaction with a functional group of the thermosetting resin. As such a curing agent, for example, known ones used in powder coatings such as amines, amides, dicyandiamides, carboxylic acids, acid anhydrides, isocyanates, polysulfides, acid dihydrazides, imidazoles, etc. may be used alone or in combination. Can be used.

  Furthermore, it is preferable that the average particle diameter of the resin A is 1 to 10 μm. When the average particle size of the resin A is less than 1 μm, when the resin B is cured, the resistance for extruding the resin A is too small, and the resin A that is cured in an island shape in the resin B It becomes more difficult to form a two-layer coating film. When the average particle size of the resin A exceeds 10 μm, when the resin B is cured, the resin A is not fully extruded, and there are many resins A that are cured in an island shape in the resin B. It becomes difficult to form a coating film having a two-layer structure.

  Furthermore, it is preferable that the content rate of the said resin A is 10 mass%-40 mass% with respect to the total mass of a powder coating material. When the content ratio of the resin A is less than 10% by mass with respect to the total mass of the powder coating material, a portion where the layer made of the resin A does not exist is formed on the layer made of the resin B. Film formation becomes difficult. Further, when the content ratio of the resin A exceeds 40% by mass with respect to the total mass of the powder coating material, the amount of the resin A that is cured in an island shape in the resin B increases, and the resin B is cured. In this case, separation of the resin A and the resin B becomes difficult.

  Furthermore, it is preferable that the loss elastic modulus at 120 ° C. of the resin A is 90% or less with respect to the loss elastic modulus at 120 ° C. of the resin B. Here, the loss elastic modulus is an index indicating dynamic viscosity, and 120 ° C. is the curing temperature of the powder coating material. When the loss elastic modulus at 120 ° C. of the resin A exceeds 90% of the loss elastic modulus at 120 ° C. of the resin B, the resin A has a high viscosity when cured, and the resin A is the resin It becomes difficult to extrude from B, and it becomes difficult to form a coating film having a two-layer structure.

The loss elastic modulus can be obtained with the following apparatus and conditions.
Apparatus: Rheometer RDA-II type manufactured by Rheometrics Measurement jig: Parallel plate with a diameter of 25 mm Measurement sample: Resin is used by compression molding into a disk shape with a diameter of 25 mm and a height of 3 mm Measurement temperature conditions: 80 to 190 ° C The temperature is raised at 2 ° C. per minute, and the value of the loss elastic modulus at 120 ° C. is read.
Measurement frequency: 6.28 rad / sec
Measurement strain setting: Automatic measurement mode (initial value set to 0.1%)

  Further, the curing temperature of the resin A is preferably higher by 5 ° C. than the curing temperature of the resin B. When the curing temperature of the resin A is not higher than the curing temperature of the resin B by 5 ° C. or more, the curing of the resin A and the resin B proceeds almost simultaneously, so that the resin A is extruded from the resin B. It becomes difficult to form a coating film having a two-layer structure. In addition, the measuring method of the said curing temperature used the temperature of the exothermic peak as the curing temperature with the temperature increase rate of 5 degree-C / min using the differential thermal scanning calorimeter (the Seiko Electronics make, SSC / 5520).

  Furthermore, the resin A is preferably an acrylic resin. The acrylic resin has an advantage of high hardness.

<Resin B>
The resin B is not particularly limited and can be appropriately selected according to the purpose. For example, an epoxy resin, an acrylic resin, a phenol resin, a xylene resin, a urea resin, Resins such as melanin resin, polyester resin, polyethylene resin, silicone resin, polyurethane resin, and polyamide resin can be used. When the main component of the resin B is a thermosetting resin, it is preferable to use a curing agent having a functional group capable of undergoing a crosslinking reaction with a functional group of the thermosetting resin. As such a curing agent, for example, known ones used in powder coatings such as amines, amides, dicyandiamides, carboxylic acids, acid anhydrides, isocyanates, polysulfides, acid dihydrazides, imidazoles, etc. may be used alone or in combination. Can be used.

  Furthermore, the resin B is preferably an epoxy resin. The epoxy resin has an advantage of excellent adhesion to a material to be coated.

<Antimicrobial agent>
The antibacterial agent is not particularly limited and may be appropriately selected depending on the intended purpose. However, the antibacterial agent includes a first apatite (apatite A) containing a metal atom having a photocatalytic function and a metal atom having an antibacterial function. 2 apatite (apatite B) is preferably included. When the antibacterial agent contains apatite A containing a metal atom having a photocatalytic function, it exhibits a strong antibacterial property due to its photocatalytic function under ultraviolet irradiation in the daytime or outdoors, and further removes foreign substances such as attached dead bodies of bacteria. Since it can be decomposed into water and carbon dioxide, antibacterial properties can be maintained over a long period of time. Further, when the antibacterial agent contains apatite B containing a metal atom having an antibacterial function, the antibacterial property can be exhibited even in a dark place and a room with a small amount of ultraviolet irradiation.

  Further, the apatite A and the apatite B are preferably dispersed in the resin A in a powder form. Thereby, antibacterial properties can be imparted evenly to the entire coating material, particularly to the coating film surface.

  Further, the total content of the apatite A and the apatite B is preferably 0.5% by mass or more and 5.0% by mass or less with respect to the total mass of the powder coating material. If the content of apatite A and apatite B is high, the antibacterial property is improved, but if the total content of both exceeds 5.0% by mass, it is difficult to maintain the original appearance of the paint, and 0.5% by mass. This is because it is difficult to exhibit antibacterial properties at less than%.

<< Apatite A >>
The apatite A is not particularly limited as long as it contains a metal atom having a photocatalytic function, and can be appropriately selected according to the purpose. For example, hydroxyapatite, fluoroapatite, chloroapatite, tricalcium phosphate Apatite in which a metal atom contained in calcium hydrogen phosphate or the like is substituted with a metal atom having a photocatalytic function is preferable, and the metal atom having the photocatalytic function is selected from Ti, Zr and W Apatite containing Ti, particularly Ti having a large photocatalytic function, is more preferable. Calcium / titanium hydroxyapatite (for example, Ca ₉ Ti (PO ₄ ) ₆ (OH) in which a part of Ca of calcium hydroxyapatite is substituted with Ti. ₂ ) is particularly preferred. This is because Ca ₉ Ti (PO ₄ ) ₆ (OH) ₂ has a large photocatalytic function.

  Moreover, it is preferable that content of the said apatite A is 0.25 mass% or more and 4.75 mass% or less with respect to the total mass of the said powder coating material. If the content of apatite A is large, the antibacterial property is improved, but if it exceeds 4.75% by mass, it is difficult to maintain the original appearance of the paint, and if it is less than 0.25% by mass, it is difficult to exhibit the antibacterial property. Because it becomes.

<< Apatite B >>
The apatite B is not particularly limited as long as it contains a metal atom having an antibacterial function, and can be appropriately selected according to the purpose. Examples of the metal atom having an antibacterial function include Ag, Cu, and Zn. Apatite containing at least one metal atom selected from among them, particularly Ag having a high antibacterial function is preferable, and calcium / silver hydroxyapatite in which Ag is added to a part of Ca of calcium hydroxyapatite (for example, antibacterial function) Is more preferably Ca ₁₀ XAg (PO ₄ ) ₆ (OH) ₂ ). Note that X in Ca ₁₀ XAg (PO ₄ ) ₆ (OH) ₂ is an arbitrary metal atom, and examples thereof include Fe, Cr, Mn, Ni, Co, and the like.

  Moreover, it is preferable that content of the said apatite B is 0.25 mass% or more and 4.75 mass% or less with respect to the total mass of the said powder coating material. If the content of the apatite B is large, the antibacterial property is improved, but if it exceeds 4.75% by mass, it is difficult to maintain the original appearance of the paint, and if it is less than 0.25% by mass, the antibacterial property is exhibited. It will be difficult.

<Other ingredients>
There is no restriction | limiting in particular as long as the said other component does not impair the effect of this invention, According to the objective, it can select suitably.

(Electronic equipment casing)
The electronic device casing of the present invention includes an electronic device casing main body, a coating film formed on the outer surface of the electronic device casing main body and made of the powder paint, and other members.

  FIG. 2 is a front view of a notebook PC casing showing an example of the electronic apparatus casing of the present invention.

  In FIG. 2, the powder coating material of the present invention is coated on the surface of the electronic device casing. As a result, a stable coating can be realized and antibacterial properties can be exhibited without reducing the amount of antibacterial agent added and without increasing the number of manufacturing steps. In addition, when the powder coating material applied to the surface of the electronic device casing includes apatite A and apatite B, it may be irradiated under ultraviolet irradiation such as in the daytime or outdoors, or in a dark place or indoor where the ultraviolet irradiation amount is small. Can also exhibit antibacterial properties.

<Electronic device housing>
There is no restriction | limiting in particular as said electronic device housing body, According to the objective, it can select suitably, For example, electronic device housing bodies, such as a notebook personal computer, a personal digital assistance (PDA), a mobile telephone, a car navigation system Is included.

<Coating film>
The coating film is not particularly limited as long as it is formed on the outer surface of the electronic device casing body and is made of the powder coating material, and can be appropriately selected according to the purpose, but it is 10 μm or more and 50 μm or less. It is preferable to have a thickness of When the thickness of the coating film is less than 10 μm, the antibacterial effect is insufficient, and even when the thickness of the coating film exceeds 50 μm, the antibacterial property does not improve and changes almost constant. Because.

<Other members>
The other members are not particularly limited as long as the effects of the present invention are not impaired, and can be appropriately selected depending on the purpose.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

Here, first, how to obtain the average particle diameter of the resin dispersed in a sea-island shape will be described.
The powder coating material was embedded in an epoxy resin, and a measurement sample was prepared in which the powder coating material was ultrathinned to about 100 nm with a microtome (LETRACUT UCT manufactured by LEICA).
Using an electron microscope (H-7650, manufactured by Hitachi, Ltd.), a plurality of TEM photographs were taken at a magnification of 1,000 with an acceleration voltage of 100 kV, and the image information was analyzed by an image processing analyzer (made by Oji Paper Co., Ltd. The image data was converted with an analyzer DA-5000S. For the target apatite particles, particles having a particle size of 0.1 μm or more were randomly sampled, and the measurement was repeated until the particle size exceeded 300 times to obtain the distribution of the volume average particle size.
Regarding the particle size of each particle, eight angles (0 degree, 22.5 degree, 45 degree, 67.5 degree, 90 degree, -22.5 degree, -45 degree, -67) are obtained for the particle projection image. .5 degrees) and the average of these dimensions is taken as the particle size of the particles.

Example 1
<Preparation of antibacterial agent-containing resin A powder>
The following four kinds of materials were put into a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.) and mixed at 2,000 rpm for 1 minute.
(1) Resin A: Acrylic resin (Number average molecular weight (Mn): 8,000, Weight average molecular weight (Mw): 40,000, Tg: 70 ° C.): 75 parts by mass (2) Curing agent: Dodecanedioic acid: 15 parts by mass (3) Antibacterial agent: apatite A: Calcium / titanium hydroxyapatite [Ca ₉ Ti (PO ₄ ) ₆ (OH) ₂ ] “TiHAP0201”: 5 parts by mass (4) Antibacterial agent: apatite B: Apatite silver “Silver Ace B-100” manufactured by Taihei Chemical Industry: 5 parts by mass

  Thereafter, using a kneader heated to 100 ° C. (KH-3-S, manufactured by Inoue Seisakusho), the pre-kneaded material melted and kneaded for 30 minutes is cooled, pulverized with a hammer mill, and then pulverized and classified with an airflow type pulverizer. To obtain an antibacterial-containing acrylic resin powder having a volume average particle diameter of 2 μm. The curing temperature of this antibacterial agent-containing acrylic resin powder was 140 ° C.

<Preparation of Colorant-Containing Resin B Powder>
Next, the following three kinds of materials were put into a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.) and mixed at 2,000 rpm for 1 minute.
(1) Resin B: Epoxy resin (Number average molecular weight (Mn): 4,000, Weight average molecular weight (Mw): 15,000, Tg: 60 ° C.): 92 parts by mass (2) Curing agent: Dicyandiamide: 3 masses Part (3) Colorant: White pigment: Rutile titanium oxide (R-960, manufactured by DuPont): 5 parts by mass

  Thereafter, using a kneader heated to 100 ° C. (KH-3-S, manufactured by Inoue Seisakusho), the pre-kneaded material melted and kneaded for 30 minutes is cooled, pulverized with a hammer mill, and then pulverized and classified with an airflow type pulverizer. The colorant-containing epoxy resin powder having a volume average particle diameter of 20 μm was obtained. The curing temperature of this colorant-containing epoxy resin powder was 130 ° C.

  Further, comparing the loss elastic modulus at 120 ° C. of the prototype antibacterial agent-containing acrylic resin powder with the loss elastic modulus at 120 ° C. of the prototype colorant-containing epoxy resin powder, the acrylic resin powder of 120 ° C. The loss elastic modulus at was 10% with respect to the loss elastic modulus at 120 ° C. of the epoxy resin powder.

<Preparation of powder coating>
20 parts by mass of the prepared antibacterial agent-containing acrylic resin powder and 80 parts by mass of the prepared colorant-containing epoxy resin particles were put into a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.). For 1 minute at 2,000 rpm.

Then, using a kneader heated to 100 ° C. (KH-3-S, manufactured by Inoue Seisakusho), the kneaded material melted and kneaded for 30 minutes is cooled, pulverized with a hammer mill, and then pulverized and classified with an airflow type pulverizer. A powder coating material was obtained in which the volume average particle size was 20 μm, the powder of 5 μm or less was 2% by mass, and the antibacterial agent-containing acrylic resin was particulate and dispersed in the colorant-containing epoxy resin.
In the powder coating material, the average particle size of the acrylic resin dispersed in the epoxy resin was 2 μm.

<Preparation of test piece>
The obtained powder coating was electrostatically coated on a magnesium alloy test piece (50 × 50 × 2 mm) using a commercially available corona charging spray gun so that the baking film thickness was 30 μm. . The applied voltage was 60 kV and the particles were negatively charged. Next, it baked for 30 minutes at 180 degreeC, and was set as the test piece. In addition, the film thickness of the coating film after drying was 20 μm.

<Evaluation of antibacterial properties>
Using the test piece and Escherichia coli, the antibacterial property of each test piece at the time of ultraviolet irradiation and in the dark was evaluated by a film adhesion method defined in JIS Z 2801. The evaluation results are shown in Table 1. Note that a black light (1 mW / cm ² ) was used for ultraviolet irradiation. The evaluation criteria are as follows.

<< Evaluation criteria >>
(1) Ultraviolet irradiation ○: The test piece having an initial number of E. coli of 1.0 × 10 ⁵ to 1.0 × 10 ⁶ was irradiated with ultraviolet rays for 10 hours, and then the number of E. coli was 100 or less. △: The test piece having an initial number of E. coli of 1.0 × 10 ⁵ to 1.0 × 10 ⁶ was irradiated with ultraviolet rays for 10 hours, and then the number of E. coli was more than 100 and 1.0. X10 Specimens with ³ or less x: Test specimens whose initial number of E. coli was 1.0 x 10 ⁵ to 1.0 x 10 ⁶ were irradiated with ultraviolet rays for 10 hours, and then the number of E. coli was Specimens with more than 1.0 × 10 ³ and 1.0 × 10 ⁶ or less (2) Storage in the dark ○: Initial number of E. coli is 1.0 × 10 ⁵ to 1.0 × 10 ⁶ After the specimen was stored in the dark for 24 hours, the number of E. coli was 100 or less. About the test piece whose initial number was 1.0 * 10 < ⁵ > -1.0 * 10 < ⁶ >, after storing for 24 hours in the dark, the number of E. coli was more than 100 and 1.0 * 10 ³ or less. The test piece which became ×: About the test piece whose initial number of colon_bacillus | E._coli was 1.0 * 10 < ⁵ > -1.0 * 10 < ⁶ >, after preserve | saving in the dark for 24 hours, the number of colon_bacillus | E._coli is 1.0 * 10 Specimens with more than ³ and less than 1.0 × 10 ⁶

(Comparative Example 1)
The epoxy resin used in “Preparation of Colorant-Containing Resin B Powder” in Example 1 is a styrene acrylic resin (number average molecular weight (Mn): 3000, weight average molecular weight (Mw): 18,000, Tg: 60 ° C. A powder coating material was prepared in the same manner as in Example 1 except that the test piece was prepared.

(Example 2-1)
The antibacterial agent-containing acrylic resin powder having a volume average particle size of 2 μm obtained in “Preparation of antibacterial agent-containing resin A powder” in Example 1 was changed to an antibacterial agent-containing acrylic resin powder having a volume average particle size of 1 μm. Except for the above, a powder coating material was prepared in the same manner as in Example 1 to prepare a test piece. The antibacterial agent-containing acrylic resin powder having a volume average particle size of 1 μm was obtained by changing the classification conditions in Example 1.

(Example 2-2)
The antibacterial agent-containing acrylic resin powder having a volume average particle size of 2 μm obtained in “Preparation of antibacterial agent-containing resin A powder” in Example 1 was changed to an antibacterial agent-containing acrylic resin powder having a volume average particle size of 10 μm. Except for the above, a powder coating material was prepared in the same manner as in Example 1 to prepare a test piece. The antibacterial agent-containing acrylic resin powder having a volume average particle size of 10 μm was obtained by changing the classification conditions in Example 1.

(Example 2-3)
The antibacterial agent-containing acrylic resin powder having a volume average particle size of 2 μm obtained in “Preparation of antibacterial agent-containing resin A powder” in Example 1 is used as the antibacterial agent-containing acrylic resin powder having a volume average particle size of 0.5 μm. Except for the change, a powder coating material was prepared in the same manner as in Example 1 to prepare a test piece. The antibacterial agent-containing acrylic resin powder having a volume average particle size of 0.5 μm was obtained by changing the classification conditions in Example 1.

(Example 2-4)
The antibacterial agent-containing acrylic resin powder having a volume average particle size of 2 μm obtained in “Preparation of antibacterial agent-containing resin A powder” in Example 1 was changed to an antibacterial agent-containing acrylic resin powder having a volume average particle size of 15 μm. Except for the above, a powder coating material was prepared in the same manner as in Example 1 to prepare a test piece. The antibacterial agent-containing acrylic resin powder having a volume average particle size of 15 μm was obtained by changing the classification conditions in Example 1.

(Example 3-1)
Instead of mixing 20 parts by mass of the antibacterial agent-containing acrylic resin powder and 80 parts by mass of the colorant-containing epoxy resin particles in “Preparation of powder coating material” in Example 1, the antibacterial agent-containing acrylic resin was mixed. A powder coating material was prepared in the same manner as in Example 1 except that 10 parts by mass of resin powder and 90 parts by mass of the colorant-containing epoxy resin particles were mixed, and a test piece was prepared.

(Example 3-2)
Instead of mixing 20 parts by mass of the antibacterial agent-containing acrylic resin powder and 80 parts by mass of the colorant-containing epoxy resin particles in “Preparation of powder coating material” in Example 1, the antibacterial agent-containing acrylic resin was mixed. A powder coating material was prepared in the same manner as in Example 1 except that 40 parts by mass of resin powder and 60 parts by mass of the colorant-containing epoxy resin particles were mixed, and a test piece was prepared.

(Example 3-3)
Instead of mixing 20 parts by mass of the antibacterial agent-containing acrylic resin powder and 80 parts by mass of the colorant-containing epoxy resin particles in “Preparation of powder coating material” in Example 1, the antibacterial agent-containing acrylic resin was mixed. A powder coating material was prepared in the same manner as in Example 1 except that 5 parts by mass of resin powder and 95 parts by mass of the colorant-containing epoxy resin particles were mixed, and a test piece was prepared.

(Example 3-4)
Instead of mixing 20 parts by mass of the antibacterial agent-containing acrylic resin powder and 80 parts by mass of the colorant-containing epoxy resin particles in “Preparation of powder coating material” in Example 1, the antibacterial agent-containing acrylic resin was mixed. A powder coating was prepared in the same manner as in Example 1 except that 50 parts by mass of the resin powder and 50 parts by mass of the colorant-containing epoxy resin particles were mixed, and a test piece was prepared.

(Example 4-1)
The epoxy resin used in “Preparation of colorant-containing resin B powder” in Example 1 is a high molecular weight epoxy resin (number average molecular weight (Mn): 4,000, weight average molecular weight (Mw): 25,000, Tg). : 65 ° C.) A powder coating material was prepared in the same manner as in Example 1 except that the test piece was prepared. In Example 4-1, the loss elastic modulus at 120 ° C. of the antibacterial agent-containing acrylic resin powder was 90% with respect to the loss elastic modulus at 120 ° C. of the colorant-containing high molecular weight epoxy resin powder.

(Example 4-2)
The epoxy resin used in “Preparation of Colorant-Containing Resin B Powder” in Example 1 is a high molecular weight epoxy resin (number average molecular weight (Mn): 4,500, weight average molecular weight (Mw): 30,000, (Tg: 65 ° C.) A powder coating was prepared in the same manner as in Example 1 except that the test piece was prepared. In Example 4-2, the loss elastic modulus at 120 ° C. of the antibacterial agent-containing acrylic resin powder was equivalent to the loss elastic modulus at 120 ° C. of the colorant-containing high molecular weight epoxy resin powder.

(Example 5-1)
The epoxy resin used in “Preparation of Colorant-Containing Resin B Powder” in Example 1 is a high molecular weight epoxy resin (number average molecular weight (Mn): 4,100, weight average molecular weight (Mw): 24,000, (Tg: 65 ° C.) A powder coating was prepared in the same manner as in Example 1 except that the test piece was prepared. In Example 5-1, the curing temperature of the colorant-containing epoxy resin powder was 135 ° C., and the difference in curing temperature from the antibacterial agent-containing acrylic resin powder was 5 ° C.

(Example 5-2)
The epoxy resin used in “Preparation of colorant-containing resin B powder” in Example 1 is a high molecular weight epoxy resin (number average molecular weight (Mn): 4,500, weight average molecular weight (Mw): 31,000, Tg: 67 ° C.) A powder coating material was prepared in the same manner as in Example 1 except that the test piece was prepared. In Example 5-2, the curing temperature of the colorant-containing epoxy resin powder was 139 ° C., and the difference in curing temperature from the antibacterial agent-containing acrylic resin powder was 1 ° C.

(Example 6-1)
The powder coating material obtained in the “Preparation of powder coating material” in Example 1 with a volume average particle size of 20 μm was changed to a powder coating material with a volume average particle size of 10 μm. A body paint was prepared and a test piece was prepared. In addition, the powder coating material whose volume average particle diameter is 10 micrometers is obtained by changing the classification conditions in Example 1. FIG.

(Example 6-2)
The powder coating material obtained in “Preparation of powder coating material” in Example 1 with a volume average particle size of 20 μm was changed to a powder coating material with a volume average particle size of 100 μm. A body paint was prepared and a test piece was prepared. In addition, the powder coating material whose volume average particle diameter is 100 micrometers is obtained by changing the classification conditions in Example 1. FIG.

(Example 6-3)
The powder coating material obtained in “Preparation of powder coating material” in Example 1 with a volume average particle size of 20 μm was changed to a powder coating material with a volume average particle size of 5 μm. A body paint was prepared and a test piece was prepared. In addition, the powder coating material whose volume average particle diameter is 5 micrometers is obtained by changing the classification conditions in Example 1. FIG.

(Example 6-4)
The powder powder obtained in “Preparation of powder paint” in Example 1 having a volume average particle diameter of 20 μm was changed to a powder paint having a volume average particle diameter of 150 μm. A body paint was prepared and a test piece was prepared. In addition, the powder coating material whose volume average particle diameter is 150 micrometers is obtained by changing the classification conditions in Example 1. FIG.

(Example 7-1)
Example except that “5 parts by mass of apatite A and 5 parts by mass of apatite B” used in “Preparation of antibacterial agent-containing resin A powder” in Example 1 was changed to “10 parts by mass of apatite A”. A powder coating material was prepared in the same manner as in Example 1 to prepare a test piece.

(Example 7-2)
Example except that “5 parts by mass of apatite A and 5 parts by mass of apatite B” used in “Preparation of antibacterial agent-containing resin A powder” in Example 1 was changed to “10 parts by mass of apatite B”. A powder coating material was prepared in the same manner as in Example 1 to prepare a test piece.

(Example 8-1) (Antimicrobial agent: 0.5 wt%)
“5 parts by mass of apatite A and 5 parts by mass of apatite B” used in “Preparation of antibacterial agent-containing resin A powder” in Example 1 were changed to “1.25 parts by mass of apatite A and 1.25 parts by mass of A powder coating was prepared in the same manner as in Example 1 except that it was changed to “Apatite B”, and a test piece was prepared.

(Example 8-2) (Antimicrobial agent: 5.0 wt%)
“5 parts by mass of apatite A and 5 parts by mass of apatite B” used in “Preparation of antibacterial agent-containing resin A powder” in Example 1 were changed to “12.5 parts by mass of apatite A and 12.5 parts by mass of A powder coating was prepared in the same manner as in Example 1 except that it was changed to “Apatite B”, and a test piece was prepared.

(Example 8-3) (Antimicrobial agent: 0.2 wt%)
The “5 parts by mass of apatite A and 5 parts by mass of apatite B” used in “Preparation of antibacterial agent-containing resin A powder” in Example 1 were changed to “0.5 parts by mass of apatite A and 0.5 parts by mass of apatite A”. A powder coating was prepared in the same manner as in Example 1 except that it was changed to “Apatite B”, and a test piece was prepared.

(Example 8-4) (Antimicrobial agent: 8.0 wt%)
“5 parts by mass of apatite A and 5 parts by mass of apatite B” used in “Preparation of antibacterial agent-containing resin A powder” in Example 1 is changed to “20 parts by mass of apatite A and 20 parts by mass of apatite B”. Except for the above, a powder coating material was prepared in the same manner as in Example 1 to prepare a test piece.

(Example 9-1) (Apatite A: 0.25 wt%)
The powder was the same as in Example 1, except that “5 parts by mass of apatite A” used in “Preparation of antibacterial agent-containing resin A powder” in Example 1 was changed to “1.25 parts by mass of apatite A”. A body paint was prepared and a test piece was prepared.

(Example 9-2) (Apatite A: 4.75 wt%)
The powder was the same as in Example 1 except that “5 parts by mass of apatite A” used in “Preparation of antibacterial agent-containing resin A powder” in Example 1 was changed to “23.75 parts by mass of apatite A”. A body paint was prepared and a test piece was prepared.

(Example 9-3) (Apatite A: 0.1 wt%)
A powder as in Example 1 except that “5 parts by mass of apatite A” used in “Preparation of antibacterial agent-containing resin A powder” in Example 1 was changed to “0.5 parts by mass of apatite A”. A body paint was prepared and a test piece was prepared.

(Example 9-4) (Apatite A: 8.0 wt%)
Powder coating material as in Example 1, except that “5 parts by mass of apatite A” used in “Preparation of antibacterial-containing resin A powder” in Example 1 was changed to “40 parts by mass of apatite A”. A test piece was prepared.

(Example 10-1) (Apatite B: 0.25 wt%)
The powder was the same as in Example 1, except that “5 parts by mass of apatite B” used in “Preparation of resin B powder containing colorant” in Example 1 was changed to “1.25 parts by mass of apatite B”. A body paint was prepared and a test piece was prepared.

(Example 10-2) (Apatite B: 4.75 wt%)
The powder was the same as in Example 1 except that “5 parts by mass of apatite B” used in “Preparation of Colorant-Containing Resin B Powder” in Example 1 was changed to “23.75 parts by mass of apatite B”. A body paint was prepared and a test piece was prepared.

(Example 10-3) (Apatite B: 0.1 wt%)
The powder was the same as in Example 1 except that “5 parts by mass of apatite B” used in “Preparation of resin B powder containing colorant” in Example 1 was changed to “0.5 parts by mass of apatite B”. A body paint was prepared and a test piece was prepared.

(Example 10-4) (Apatite B: 8.0 wt%)
Powder coating material as in Example 1, except that “5 parts by mass of apatite B” used in “Preparation of colorant-containing resin B powder” in Example 1 was changed to “40 parts by mass of apatite B”. A test piece was prepared.

(Example 11-1)
Instead of “electrostatic coating so that the baked film thickness is 30 μm” in “Preparation of Test Specimen” in Example 1, “static coating is performed so that the baked film thickness is 10 μm”. A powder coating was prepared in the same manner as in Example 1 except that “painted”, and a test piece was prepared. In addition, the film thickness of the coating film after drying was 10 μm.

(Example 11-2)
Instead of “electrostatic coating so that the baked film thickness becomes 30 μm” in “preparation of test specimen” in Example 1, “static coating so that the baked film thickness becomes 50 μm” A powder coating was prepared in the same manner as in Example 1 except that “painted”, and a test piece was prepared. In addition, the film thickness of the coating film after drying was 50 μm.

(Example 11-3)
Instead of “electrostatic coating so that the baked film thickness becomes 30 μm” in “preparation of test piece” of Example 1, “electrostatic so that the baked film thickness becomes 5 μm” instead of “electrostatic coating so that the baked film thickness becomes 30 μm”. A powder coating was prepared in the same manner as in Example 1 except that “painted”, and a test piece was prepared. In addition, the film thickness of the coating film after drying was 5 μm.

(Example 11-4)
Instead of “electrostatic coating so that the baked film thickness becomes 30 μm” in “preparation of test piece” in Example 1, “static coating so that the baked film thickness becomes 60 μm” A powder coating was prepared in the same manner as in Example 1 except that “painted”, and a test piece was prepared. In addition, the film thickness of the coating film after drying was 60 μm.

In addition, in the problems of Table 1, “completely two layers”, “thin upper layer thickness”, “small amount of antibacterial agent near the surface”, “difficult to flatten coating film”, and “strength of coating film” “Low” is a level that does not cause a practical problem.

Example 12
A test piece was prepared in the same manner as in Example 1 except that, in “Production of test piece” in Example 1, “Aluminum test piece” was used instead of “Magnetic alloy test piece”.
As a result, the same result as that applied to the magnesium alloy test piece in Example 1 was obtained.

(Comparative Example 2)
In the same manner as in “Preparation of antibacterial agent-containing resin A powder” in Example 1, an antibacterial agent-containing acrylic resin powder having a volume average particle size of 2 μm was prepared. The white pigment-containing epoxy resin powder having a volume average particle diameter of 20 μm was prepared in the same manner as in “Preparation of”. 20 parts by mass of the prepared antibacterial agent-containing acrylic resin powder and 80 parts by mass of the prepared white pigment-containing epoxy resin powder were put into a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.). The mixture was mixed at 2,000 rpm for 1 minute to obtain a powder coating material. The obtained powder coating is in a state where two kinds of resin powders are mixed.
Next, in the same manner as in Example 1, the obtained powder paint was baked onto a magnesium alloy test piece (50 × 50 × 2 mm) using a commercially available corona charging spray gun. Electrostatic coating was performed so that the thickness was 30 μm. The applied voltage was 60 kV and the particles were negatively charged. Next, it baked for 30 minutes at 180 degreeC, and was set as the test piece.
In the powder coating before painting, the acrylic resin powder and the epoxy resin powder were mixed in a ratio of 2: 8. However, since the acrylic resin powder has a smaller particle size, the chargeability is higher. The ratio of the powder is not 2: 8, but the acrylic resin powder is coated more than the mixing ratio before coating, and the two types of resin powder cannot be applied at the mixing ratio before coating. There was a problem that could not be realized. In addition, many acrylic resin powders that do not contribute to painting and are discarded are generated.

As described above, by coating the home appliance / electronic equipment casing with the powder coating of the present invention, it has excellent antibacterial antifouling properties for a long period of time with few steps and low cost against various bacterial stains. It can be given over.
Further, by using a powder paint containing apatite A and B, bacteria attached through human hands and the like are sterilized by, for example, apatite silver even when placed in a dark place without ultraviolet irradiation. In addition, when exposed to ultraviolet rays, the antibacterial substance on the surface is always exposed to the surface because it exhibits stronger antibacterial properties and decomposes foreign substances such as dead bacteria. This makes it possible to form a coating film having antibacterial properties over a long period of time.

Here, it will be as follows if the preferable aspect of this invention is appended.
(Additional remark 1) It contains 1st resin, 2nd resin, and an antibacterial agent, the said antibacterial agent is unevenly distributed in said 1st resin, and said 1st resin and said 2nd resin are non-phase. A powder coating material, wherein the first resin is in the form of particles and dispersed in the second resin.
(Additional remark 2) The powder coating material of Additional remark 1 whose average particle diameter of said 1st resin currently disperse | distributed in said 2nd resin is 1-10 micrometers.
(Additional remark 3) The powder coating material of Additional remark 1 or 2 whose content rate of said 1st resin is 10 mass%-40 mass% with respect to the total mass of a powder coating material.
(Additional remark 4) The loss elastic modulus in 120 degreeC of said 1st resin is 90% or less with respect to the loss elastic modulus in 120 degreeC of said 2nd resin, The powder in any one of Additional remark 1 thru | or 3 paint.
(Additional remark 5) The powder coating material in any one of additional remarks 1 thru | or 4 whose curing temperature of said 1st resin is 5 degreeC or more higher than the curing temperature of said 2nd resin.
(Appendix 6) The powder according to any one of appendices 1 to 5, wherein the antibacterial agent includes a first apatite containing a metal atom having a photocatalytic function and a second apatite containing a metal atom having an antibacterial function. paint.
(Additional remark 7) It has the coating film which consists of an electronic equipment housing | casing main body and the said electronic equipment housing | casing main body, and consists of powder coating material, The said powder coating material contains 1st resin, 2nd A resin and an antibacterial agent, wherein the antibacterial agent is unevenly distributed in the first resin, the first resin and the second resin are incompatible, and the first resin is in the form of particles. An electronic device casing which is dispersed in the second resin.
(Supplementary note 8) The electronic device casing according to supplementary note 7, wherein the second resin is more unevenly distributed near the electronic device casing body than the first resin, and the antibacterial agent is unevenly distributed near the surface of the coating film. .

FIG. 1A is a diagram showing a production process of a coating film made of the powder paint of the present invention (part 1). FIG. 1B is a diagram showing a production process of a coating film made of the powder paint of the present invention (No. 2). FIG. 1C is a diagram showing a production process of a coating film made of the powder paint of the present invention (No. 3). FIG. ID is a figure which shows the manufacturing process of the coating film consisting of the powder coating material of this invention (the 4). FIG. 1E is a diagram showing a process for producing a coating film comprising the powder paint of the present invention (No. 5). FIG. 2 is a front view of a notebook PC casing showing an example of the electronic apparatus casing of the present invention. FIG. 3 is a diagram for explaining a coating film made of a conventional powder coating material.

Explanation of symbols

10 Resin A
11 Resin B
12 Antibacterial agent (antibacterial inorganic particles)
30 Coating film (resin)
31 Antibacterial agent (antibacterial inorganic particles)

Claims (5)

  A first resin, a second resin, and an antibacterial agent, wherein the antibacterial agent is unevenly distributed in the first resin, and the first resin and the second resin are incompatible, The powder coating material, wherein the first resin is particulate and dispersed in the second resin.   The powder coating material according to claim 1, wherein an average particle diameter of the first resin dispersed in the second resin is 1 µm to 10 µm.   The powder coating material according to claim 1 or 2, wherein the content ratio of the first resin is 10% by mass to 40% by mass with respect to the total mass of the powder coating material.   The powder coating material according to any one of claims 1 to 3, wherein a loss elastic modulus at 120 ° C of the first resin is 90% or less with respect to a loss elastic modulus at 120 ° C of the second resin. .   An electronic device casing main body, and a coating film formed on the outer surface of the electronic device casing main body and made of a powder coating, wherein the powder coating includes a first resin, a second resin, and an antibacterial The antibacterial agent is unevenly distributed in the first resin, the first resin and the second resin are incompatible, and the first resin is particulate and the second resin An electronic device casing that is dispersed in resin.