JP5036675B2 - Filter and air conditioner - Google Patents

Description

  The present invention relates to a filter that captures dust contained in passing air, an air conditioner that uses the filter, and an air conditioner that includes a filter and a filter cleaning device that automatically removes dust captured by the filter. .

  The air conditioner is provided with a heat exchanger that performs heat exchange between the air passing therethrough and the refrigerant circulating in the refrigeration cycle. The heat exchanger is composed of a plurality of thin plate-like metal fins arranged so as to be parallel to each other, and a metal refrigerant pipe inserted through the fins in a plurality of rows. ing. Aluminum is often used as the material for the fins, and copper pipes are mainly used for the refrigerant piping.

  A filter is provided on the front surface (upstream side) of the heat exchanger in order to prevent the air passing through it from becoming clogged due to dust and lint getting caught between the fin tips and the fins of the heat exchanger. ing. In the conventional filter maintenance method, manual cleaning such as washing with water is performed about once every two weeks. In recent years, in order to save the trouble of filter cleaning, a mechanism for automatically cleaning the filter at regular intervals is provided in the air conditioner. As a method for automatic cleaning, a method of scraping dirt with a cloth brush, a wire brush, a fiber brush, silicon or an adhesive tape made of a brushed material, or a method of sucking with a suction fan is used.

  On the surface of the filter, not only relatively long lint but also various kinds of dirt such as hydrophilic dust and yellow sand, hydrophobic oil smoke, cigarette dust, dirt and human sebum are captured. When the dirt on the surface of the filter is scraped off with a brush, there is no problem if it is only fiber dust. However, since fine dirt, sebum, sand dust, and oil adhere to the filter, these act as a binder. , It becomes difficult to scrape even dirt caused by fiber dust with a brush. In the worst case, not only the dirt cannot be scraped off, but also the dirt is spread and the eyes of the filter are filled. When the eyes of the filter are filled, the air volume (air flow rate) passing through the filter and the wind reaching force are reduced, and the heat exchange amount in the heat exchanger is reduced for this reason, and the air conditioning capability is reduced. The dirt that can be removed by manually washing with water is not easy to remove in the automatic cleaning mechanism because such fine dirt on the micron order is difficult to remove.

  For this reason, various methods for suppressing filter fouling have been proposed. For example, there is one that makes it easy to remove attached dirt by coating the surface of a filter with a fluorine compound having a low surface energy (see, for example, Patent Document 1).

  In addition, there is a method in which a stainless metal film is formed on the surface of a filter by sputtering so that dirt is easily peeled off due to the smoothness of the surface (see, for example, Patent Document 2).

In addition, there is a filter that has a self-cleaning effect that can be easily washed away using water by containing a photocatalyst on the filter surface (see, for example, Patent Document 3).
JP-A-6-136062 JP 2007-105645 A JP 9-75633 A

  However, the filter coated with the fluorine compound disclosed in Patent Document 1 has an effect that the adhesion of dirt is reduced due to low surface energy and the dirt is easily peeled off. However, because fluorine itself is hydrophobic (has a low affinity for water, that is, it is difficult to dissolve in water, or a substance or molecule that is difficult to mix with water), hydrophobic particles and hydrophobic gases are On the other hand, it tends to adhere, and in many places where oil smoke or tobacco environmental load is high, it tends to become more dirty. If a large amount of these adhere and adhere, automatic cleaning with a brush is difficult even if the effect of the fluorine compound is present.

  Further, the filter in which the metal stainless steel disclosed in Patent Document 2 is sputtered on the surface can suppress the physical catching of dirt because the smoothness of the surface is increased, and is easily peeled off. However, although it is hard to get dirty and easily peels off as compared with conventional resins, stainless steel itself is hydrophobic and has a large adhesion area, so that hydrophobic dirt adheres well. Further, when compared with the coating of the present invention described later, since the surface density is high, the intermolecular force with the dirt particles becomes high and the dirt is difficult to remove.

  In addition, the filter containing a photocatalyst on the filter surface shown in Patent Document 3 is designed to partially exhibit hydrophilicity by photoexcitation caused by irradiating light to the photocatalytic oxide. However, there is a problem in that good antifouling performance cannot be obtained when is not sufficient. In particular, in a normal air conditioner environment, the filter is covered with an outer shell, so that it is difficult to obtain sufficient light. Furthermore, even if there is a self-cleaning effect that can be easily washed away using water, when applied to an automatic cleaning filter, it cannot be washed away because there is no water.

  Of course, in the automatic cleaning mechanism with a conventional PET (polyethylene terephthalate) filter without coating, both hydrophilic and hydrophobic, such as hydrophilic dust and yellow sand, hydrophobic oil smoke and cigarette dust, dirt, sebum, etc. The dirt will adhere evenly. Unlike fiber dust, which has a diameter of 0.1 to 5.0 millimeters, fine dirt, sebum, sand dust, and oil droplets are only a few microns. Since these adhere to the filter, they act as a binder, so that there is a risk that the dirt becomes difficult to scrape off with a brush, or the dirt is pushed and spread, causing clogging of the filter.

  This invention has been made to solve the above-mentioned problems, and exhibits antifouling performance against all types of dirt regardless of hydrophilicity or hydrophobicity, thereby improving the adhesion prevention and release of dirt. An object of the present invention is to provide a filter provided with a filter coating, an air conditioner using the filter, and an air conditioner having a filter cleaning device that automatically removes the filter and dust trapped in the filter. .

The filter according to the present invention is:
A filter frame;
A net-like filter vent installed in the filter frame;
A coating film is formed on the surface of the filter ventilation body and contains silica fine particles and fluororesin particles. The coating film is partially exposed from the surface of the silica film in the silica film composed of silica fine particles. And a coating composition in which the exposed area of the silica film is larger than the exposed area of the fluororesin particles.

  In the filter according to the present invention, a coating film is formed on the surface of the filter ventilation body, containing silica fine particles and fluororesin particles, wherein the coating film is a silica film composed of silica fine particles and the fluororesin particles are silica films. A hydrophilic fouling substance and a hydrophobic substance are provided by being provided with a coating composition that is interspersed so as to be partially exposed from the surface and in which the exposed area of the silica film is larger than the exposed area of the fluororesin particles. In addition to exhibiting excellent antifouling performance against both fouling substances, it has the effect of exhibiting good releasability by low intermolecular force and low electrostatic force, and has the effect of preventing clogging of the filter.

  Hereinafter, a filter cleaning device and a filter according to embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding portions are denoted by the same reference numerals, and a part of the description is omitted.

Embodiment 1 FIG.
In this embodiment, the filter surface is clogged by coating the filter surface with a suitable coating composition (hydrophobic fluororesin particles dispersed and dispersed in a hydrophilic silica film). There is a feature in preventing.

  Before describing the filter coated with the above-described coating composition suitable for the filter surface, an air conditioner which is an example of an apparatus using the filter will be described. The air conditioner described below is an air conditioner having a filter coated with the above-described coating composition suitable for the filter surface, and a filter cleaning device that automatically removes dust trapped in the filter.

  FIG. 1 is a cross-sectional view at a substantially central portion in a side view schematically showing an air conditioner 100 according to the first embodiment. In FIG. 1, an air conditioner 100 is installed in a casing 10, a casing 10, a blower fan 20 that sucks air and blows out the sucked air, and an air path formed by the blower fan 20. The heat exchanger 30 that exchanges heat between the sucked air and the refrigerant (enclosed in the refrigeration cycle), the filter 40 that captures dust contained in the sucked air, and the filter cleaning device 50 that cleans the filter 40 ,have. Hereinafter, each component will be described individually.

  The casing 10 has a cylindrical shape in which both end surfaces (not shown) are closed, a part of the top surface (upper side in the figure) is opened, and the opening portion forms a suction port 11 for sucking air. A part of the ground (lower side in the figure) is opened to form an air outlet 14 for blowing out air sucked from the air inlet 11. And the front surface (left side in the figure) is opened, and a front door 12 for opening and closing the opening is installed. In addition, the rear surface (right side in the figure) is closed, and a wall attaching portion 16 for attaching the housing 10 to a wall or the like is formed in the upper portion.

  Inside the housing 10, a special member is installed in a range in which the cross-section of the "side A" near the rear surface near the top surface and the "front side B" near the front surface and "position B" near the ground surface is circular. A space not provided is prepared, and the space is an arcuate moving path 17 that becomes a moving path of the filter 40.

  The blower fan 20 is disposed at a substantially central portion in a side view of the housing 10. The blower fan 20 is disposed in an air path formed between the suction port 11 and the blower port 14. The front and rear of the blowing side air passage between the blower fan 20 and the outlet 14 are formed by the nozzle 13 and the rear guide plate 15.

  The heat exchanger 30 is disposed between the suction port 11 and the blower fan 20 and harmonizes the sucked air (cooling, heating, humidification, dehumidification, etc.). In the drawing, the heat exchanger 30 is disposed so as to surround the top surface side and the front surface side of the blower fan 20, but the present embodiment is not limited to the disposition form. The heat exchanger 30 includes a heat transfer tube 31 and heat radiating fins 32 through which the heat transfer tube 31 is inserted.

  FIG. 2 is a perspective view schematically showing the filter 40 shown in FIG. 1 and 2, the filter 40 is formed of a mesh-like filter vent 41 and a filter frame 42 on which the filter vent 41 is installed. The filter frame 42 forms a part of a substantially cylindrical shape (circular arc shape), and is formed of a rectangular outer frame 43 and a reinforcing bar 44 that connects opposite sides of the outer frame 43 before forming the circular arc shape. Is done. A filter driven gear 45 made of an internal gear is formed on the inner surface of the reinforcing bar 44.

  The filter 40 reciprocates along the arcuate moving path 17 in a range where the upper edge 46 reaches the position A and the lower edge 47 reaches the position B. The filter frame 42 The radius of curvature of the arc of the cross section (same as the filter 40) is substantially equal to the radius of curvature of the arcuate moving path 17. That is, since the filter 40 reciprocates without changing the radius of curvature, not only the filter 40 can be moved by a simple device, but also the filter 40 itself is prevented from being deteriorated and the life is extended.

  FIG. 3 is a detailed view of the filter vent 41. The filter vent 41 is woven with warp and weft made of PET (polyethylene terephthalate). Moreover, when scraping off dust with the roll-shaped brush 71, it has a plain weave shape with no irregularities so that the brush can be in good contact and efficiently remove dust. The shape of the mesh (mesh) is quadrangular, and the total number of wefts and warps is set to at least 40 per inch * 1 inch to increase the collection efficiency per mesh (one mesh One side is about 0.6mm). The number of wefts and warps may be the same or one may be greater than the other. The thickness (wire diameter) of the yarn is determined from pressure loss and strength, and is approximately 20 to 100 d (denier). The present embodiment is directed to a plain weave filter having a square mesh, but the present invention is not limited to this, and the mesh may be a hexagon or a triangle. Even if it is solid weave instead of plain weave, it can be applied without problems.

  The filter ventilation body 41 has a role of mainly preventing dust accumulation on the heat exchanger 30 by physical collection, and the length of the dust collection target is 0.1 mm to 10 mm which scatters in the air. There is a large amount of fibrous waste thread 92 in general. However, various dirt such as dust and yellow sand of the hydrophilic fouling substance 90, oily smoke and dust of the hydrophobic fouling substance 91, human dirt and sebum are scattered in the air, and these are several micrometers in size. Although it is very small, it adheres on the filter fiber. In particular, when sticky dirt such as dirt is attached, the dust attached thereto is difficult to peel off from the filter 40, and is difficult to remove even by rubbing with the roll brush 71. In addition, since such dirt becomes a nutrient of mold and fungi, when the room is exposed to a high humidity environment, the mycelium grows on the filter 40 and causes strong clogging. Clogging of the filter 40 makes it difficult for air to pass at the normal rotation speed of the blower fan 20 (cross flow fan). Therefore, the air conditioning capacity decreases, the heating airflow reaches the floor, the heating airflow rises, and the cooling airflow. It has various adverse effects such as discomfort due to dripping, generation of abnormal noise due to reverse suction near the blowout, and deterioration of electricity bill. FIG. 4 shows the rate of deterioration of the electricity bill due to the filter 40 that is clogged. As the pressure loss of the filter 40 increases, the electricity cost in the same capacity comparison deteriorates by about 10 to 20%.

  In FIG. 1, a filter cleaning device 50 includes a filter moving unit 60 that moves the filter 40, a dust removing unit 70 that comes into contact with the filter vent 41 of the filter 40 and removes the trapped dust, and a dust removing unit. And a dust collection unit 80 for collecting the dust removed by 70.

  In FIG. 1, the filter moving unit 60 is fixed to one end of the filter drive shaft 62, a filter drive gear 61 that meshes with the filter driven gear 45, a filter drive shaft 62 in which the filter drive gear 61 is fixed substantially at the center. A filter rotation input gear (not shown) and a filter moving part main body 64 that rotatably supports the filter drive shaft 62 are provided.

  Further, the filter moving part main body 64 is provided with a filter pressing shaft 65 in parallel with the filter driving shaft 62. The filter pressing shaft 65 is moved when the filter driving gear 61 is engaged with the filter driven gear 45 and the filter 40 is moved. , So that the mesh is not disengaged. Note that the filter pressing shaft 65 may be a rotatable circular cross section or a fixed cross sectional rectangle.

  FIG. 5 is a perspective view schematically showing the dust removing unit 70 shown in FIG. 1 and 5, the dust removing unit 70 includes a roll brush 71 that rotates in contact with the outer surface of the filter vent 41 of the filter 40, a roll brush drive shaft 72 to which the roll brush 71 is fixed, A roll brush rotation input gear 73 fixed to one end of the roll brush drive shaft 72 and a dust removing unit main body 74 that rotatably supports the roll brush drive shaft 72 are provided.

  A cylindrical shaft penetration protrusion (not shown) is formed on one end face of the dust removing portion main body 74, the roll brush drive shaft 72 passes through the shaft penetration protrusion, and the other end face is cylindrical. A shaft support protrusion 75 having a cup shape with the end closed is formed, and the end of the roll-shaped brush drive shaft 72 is supported inside the shaft support protrusion 75. Then, the roll brush 71 is rotated or stopped, and the dirt on the filter 40 is scraped to remove dust.

  Although the above description shows the roll brush 71 that is rotationally driven as the dust removing unit 70, the present embodiment is not limited to this, and instead of the roll brush 71, fibers are added to the brush. An implanted wire brush may be installed. Alternatively, the dust on the filter 40 may be swept away by moving the wire brush back and forth without fixing it. The pressing force to the filter 40 can be changed by adjusting the length and material of the wire and the distance from the filter 40. Further, the filter 40 may be rubbed with a member such as a silicon pad.

  The roll brush 71 can be in closer contact with the filter 40, but if the dust on the filter 40 is difficult to peel off, there is a high risk that the dust will be spread or left in the filter 40. Further, after the dirt of the filter 40 has moved to the entire roll-shaped brush 71, there is a risk that dirt will accumulate on the roll-shaped brush 71 because the contact area of the roll-shaped brush 71 itself is large. On the other hand, in the case of a wire brush, there are few parts which correspond to the filter 40, and since pressing force changes with the dispersion | variation in the distance of the filter 40 and wire brush, when dirt is hard to peel, there exists a risk that a removal power falls remarkably.

  In FIG. 1, the dust collecting unit 80 is a scraping plate 81 that scrapes off dust trapped in contact with the roll brush 71, and scraping biasing means for pressing the scraping plate 81 against the roll brush 71. 82 and a dust collection box 83 for storing the dust scraped off by the scraping plate 81.

  Since the dust removing unit main body 74 of the dust removing unit 70 functions as an “opening / closing lid” of the dust collecting box 83 of the dust collecting unit 80, when the dust removing unit main body 74 is aligned with the dust collecting box 83, the dust removing unit main body 74. The dust box 83 and the roll brush 71 form a substantially sealed dust box.

  The filter 40 is moved to the lower limit. That is, the filter 40 moves along the arcuate moving path 17 from the state where the upper edge 46 is at the position A until the lower edge 47 reaches the position B.

  Then, in the “outward path” where the filter 40 is moved by the filter driving gear 61 that rotates in the forward direction (counterclockwise in the drawing) and moves from the position A to the position B, the roll brush 71 moves in the moving direction of the filter 40 ( The dust rotates in the same direction (clockwise in the figure) as the substantially downward direction in the figure, and dust trapped by the filter vent 41 is removed. In particular, since the peripheral speed (Vb) of the roll brush 71 is slower (Vb <Vf) than the moving speed (Vf) of the filter 40, the dust trapped in the filter vent 41 is temporarily removed from the roll brush. After being collected on the biting side of 71 (the top surface side in the figure), it adheres to the roll brush 71 and is carried to the biting side (the ground side in the figure). The attached dust is scraped off by the scraping plate 81 and collected in the dust collection box 83.

  On the other hand, the filter 40 that has reached the lowering limit is moved by the filter drive gear 61 that rotates in the reverse direction (clockwise in the drawing) and returns to the rising limit (see FIG. 1). That is, the upper edge 46 reaches the position A.

  In the “return path” from the position B to the position A, the roll brush 71 stops rotating. Therefore, even if the dust that has not been removed in the forward path is removed in the return path, the dust is only collected on the biting side (the ground side in the figure) of the non-rotating roll-shaped brush 71 and bite. It is not carried to the delivery side (the top side in the figure). Therefore, the dust removed from the roll brush 71 does not dissipate out of the dust collection box 83.

  The filter cleaning device 50 has been described with a method in which the dust trapped in the filter vent 41 is bitten by the roll brush 71. However, although not described in detail, the suction-type filter cleaning device also has a filter coating described below. The filter 40 coated with the composition is effective.

  Next, the filter coating composition for suppressing clogging of the filter 40, which is a characteristic part of the present embodiment, will be described.

  As an example of an article to be coated with the coating composition 200 described below, a filter 40 used in the air conditioner 100 is used here. However, the coating composition 200 is not limited to the filter 40 and can be applied to other articles.

  In addition to exhibiting excellent antifouling performance against both the hydrophilic fouling substance 90 and the hydrophobic fouling substance 91 on the filter 40, there is an effect of exhibiting good peelability by a low intermolecular force and a low electrostatic force. The filter coating composition for obtaining the effect of preventing the clogging of the filter by reducing dust spreading and removal residue by the cleaning device 50 will be described with reference to the drawings.

  FIG. 6 is an explanatory view showing a cross section in a state where the coating composition 200 of the first embodiment is coated on the filter vent 41 (filter fiber 107) of the filter 40 to be coated and the coating film 103 is formed. It is a conceptual diagram for. FIG. 7 is a conceptual diagram showing only a portion of the coating film 103 by the coating composition 200 in FIG. FIG. 8 is a conceptual view of the top surface of the coating film 103 of FIG. 6 or FIG. 6 to 8 all show a state in which the coating composition 200 is dried to form the coating film 103.

  In the dried coating composition 200 of Embodiment 1, the fluororesin particles 102 having hydrophobicity are scattered in the silica film 104 having hydrophilicity composed of the silica fine particles 101, and all of the silica film 104 is dispersed. Instead, a partially exposed coating film 103 is formed.

Silica (SiO ₂ ) is an oxide of silicon that occupies about 60% of the earth's crust, and is mainly used in various fields by chemically reacting mainly with silica sand as a raw material to produce porous silica with a large surface area structure. Produce superior properties. Along with its chemical stability, it is in the spotlight in a wide range of fields.

  The coating composition 200 is obtained by mixing water (dispersion) in which the silica fine particles 101 are dispersed and water (dispersion) in which the fluororesin particles 102 are dispersed, and the coating film 103 is formed. Before being applied, it is in a liquid state in which the silica fine particles 101 and the fluororesin particles 102 are dispersed in water, and the dispersion (coating solution) is applied to the surface of the article, or the article is immersed in the dispersion. Then, the coating film 103 is formed on the surface of the article by drying to remove moisture. The silica film 104 in the coating film 103 is a film in which the bonding of silicon Si and oxygen O continues and has an OH group on the surface.

  Here, as shown in FIG. 7, the coating layer formed on the surface of the article by the coating composition 200 is referred to as a coating film 103. The coating film 103 is in a state where the fluororesin particles 102 are scattered in the silica film 104 made of the silica fine particles 101 and the fluororesin particles 102 are partially exposed from the surface of the silica film 104. It is what. In addition, here, the coating composition 200 basically refers to a state generally referred to as a coating solution that is in the state of the above-described dispersion.

  The average particle diameter (average particle diameter) of the silica fine particles 101 used in the coating composition 200 is 15 nm or less, preferably 4 to 12 nm when measured by a light scattering method. The particle size can be measured by a light scattering method. Thus, in the state of the coating solution dispersed in water, the silica fine particles 101 having an extremely small average particle diameter are in a state where all the surface portions in contact with water are in equilibrium and are partially dissolved in water (the surface in contact). When the coating composition 200 is dried, the semi-dissolved silica component becomes a binder that connects the silica fine particles 101 to each other (a binder that hardens the particles). ), The silica fine particles 101 aggregate and solidify easily after drying without adding a special binder. Therefore, it is possible to obtain the silica film 104 that is excellent in strength, such as being hard to crack, and thus the coating film 103.

  In the silica fine particles 101 having an average particle diameter in the range of 4 to 15 nm, the surface portion corresponding to approximately 15 to 30% of the weight of the silica fine particles 101 is half water in the coating solution. It is in a dissolved state. However, in the case of silica particles having an average particle size of more than 15 nm, the larger the average particle size, the smaller the weight of the silica component that is semi-dissolved in water in the coating solution with respect to the weight of the silica fine particles 101, and the action as a binder. Since it cannot be obtained, the formed coating film 103 does not have sufficient strength and is not preferable as a coating film because cracks are easily generated. Therefore, it becomes necessary to add a binder separately.

  On the contrary, in the case of the silica fine particles 101 having an average particle size of less than 4 nm, the ratio of the silica component dissolved in the water becomes too high in the coating solution, and the silica fine particles 101 aggregate in the coating solution. For example, the stability as the coating composition 200 cannot be obtained. Also, the strength of the silica film 104 (coating film 103) formed after drying and the antifouling performance described later cannot be obtained.

  The particle size of the silica fine particles 101 also affects the appearance characteristics such as transparency of the coating film 103 to be formed. If the silica fine particle 101 has an average particle size of 15 nm or less, the scattering of light reflected by the coating film 103 is reduced, so that the transparency of the coating film 103 is improved, and changes in the color tone and texture of the coating object are suppressed. The color tone and texture of the object to be coated can be kept intact.

  Further, by using silica fine particles 101 having an average particle size of 15 nm or less as silica fine particles 101, the silica film 104 in the coating film 103 obtained has fine voids between the silica fine particles 101 while being dense. It becomes. The silica film 104 is thinner than a conventional silica film that does not use fine particles formed by a silicate or sol-gel method or a silica film to which a binder made of a soluble organic or inorganic material is added. Since it can be formed and can be formed smoothly by reducing the irregularities on the surface of the silica film 104 due to the silica particles, the fouling substance is not caught and the antifouling performance is improved.

  The content of the silica fine particles 101 in the coating composition 200 is 0.1 to 5% by weight, preferably 0.3 to 2.5% by weight with respect to the coating composition 200. Using the coating composition 200 with a content (concentration) in this range, a liquid film is formed on the surface of the object to be coated (for example, the heat exchanger 30) by dipping or spraying, and the excess coating solution is washed away. When the coating is performed by forcibly removing or drying, the thickness of the coating film 103 to be formed is about 50 to 500 nm, and the silica film 104 can have a uniform thickness without unevenness. The coating film 103 that does not impair the color tone and texture of the surface of the object to be coated can be formed.

  When the content of the silica fine particles 101 is less than 0.1% by weight, the silica film 104 becomes too thin and partial defects occur, resulting in a portion that cannot be coated on the surface of the object to be coated. May occur, which makes the coating composition 200 unsuitable.

  On the other hand, if the content of the silica fine particles 101 exceeds 5% by weight, the silica film 104 becomes too thick to become a cloudy film, which impairs the color tone and texture of the surface of the object to be coated. Further, since the silica fine particle 101 itself has a large weight ratio, it becomes difficult to obtain a binder action due to the silica component dissolved in the half-water in the coating solution, and the solidified state of the silica fine particles 101 after drying becomes weak. The film 104 is inferior in strength, such as being easily cracked or easily peeled off.

  Next, the fluororesin particles 102 used in the coating composition 200 will be described. In the coating film 103, the average particle diameter (average particle diameter) of the fluororesin particles 102 that are scattered in the silica film 104 and partially exposed from the silica film 104 is not 50 to 500 nm, preferably 100. Those with ~ 250 nm are used. The particle size can be measured by a light scattering method. By using a particle having a particle diameter in such a range, the particle diameter becomes larger than the thickness of the silica film 104, and the fluororesin particles 102 are easily dispersed in the silica film 104 in the formed coating film 103. The fluororesin particles 102 are easily partially exposed on the surface of the coating film 103 (from the surface of the silica film 104), and a desired state of the coating film 103 can be obtained.

  If the fluororesin particles 102 have an average particle size of less than 50 nm, the stability of properties cannot be obtained, for example, the fluororesin particles 102 aggregate and coalesce in the coating solution. Further, in the coating film 103 to be formed, the fluororesin particles 102 are hardly exposed from the surface of the silica film 104, and the antifouling performance described later cannot be obtained.

  On the other hand, if the average particle diameter is the fluororesin particles 102 exceeding 500 nm, the portion of the fluororesin particles 102 exposed from the surface of the silica film 104 in the formed coating film 103 becomes large. In such a case, the region of the hydrophobic portion on the surface of the coating film 103 becomes too large, and the antifouling performance described later cannot be obtained. Moreover, the unevenness | corrugation of the coating film 103 surface becomes large too much, and a fouling substance (dirt) becomes easy to be caught, and the adhering fouling substance becomes difficult to be removed.

  In the coating film 103 formed by drying the coating composition 200 on the surface of the object to be coated, the thickness of the silica film 104 is smaller than the average particle diameter of the fluororesin particles 102. By managing the thickness of the silica film 104 to be smaller than the average particle diameter of the fluororesin particles 102, the fluororesin particles 102 are dispersed and dispersed in the silica film 104 in the coating film 103 to be formed, The silica film 104 can be partially exposed from the surface of the silica film 104, and a desired state of the coating film 103 can be obtained.

  For example, when the fluororesin particles 102 having an average particle diameter of 150 nm are used, the thickness of the silica film 104 is controlled to be less than 100 nm. That is, the thickness of the silica film 104 is set to be less than 2/3 of the average particle diameter of the fluororesin particles 102. Thus, in order to form the silica film 104 into a thin film having a thickness of less than 100 nm, the coating solution on the surface of the object to be coated may be blown with a strong air current before the silica fine particles 101 are solidified on the surface of the object to be coated. The thickness of the silica film 104 can be managed by adjusting factors such as the blow speed, blow time, and blow temperature.

  The weight ratio of the silica fine particles 101 to the fluororesin particles 102 in the coating composition 200 (the weight of the silica fine particles 101 is the weight of the fluororesin particles 102) is 50:50 to 95: 5, and preferably 75:25. If the weight ratio is in such a range, the coating film 103 in which the hydrophilic region formed by the silica fine particles 101 (silica film 104) and the hydrophobic region formed by the fluororesin particles 102 are mixed in a balanced manner can be obtained by drying at room temperature. . The good balance between the hydrophilic region and the hydrophobic region affects the antifouling performance described later.

  However, even when the pure silica film 104 is formed using only the silica fine particles 101, the antifouling effect is considerably limited, but the effect of keeping away hydrophobic particles such as oil smoke and the electrostatic force and intermolecular force of the surface. As compared with the case where no coating is applied, the stain resistance is improved.

  Hereinafter, the antifouling performance (antifouling property) by the coating film 103 formed by the coating composition 200 will be described. The term “dirt” means that a fouling substance adheres to the surface of the article and is fixed to the article surface without being removed. Therefore, it is possible to prevent the fouling substances from adhering to the surface of the article, and even if fouling substances adhere to the surface of the article, the fouling substances can be easily removed from the surface without adhering to the surface. This will prevent contamination.

  In this way, the property that the pollutant is difficult to adhere to the surface, and the property that it can be easily removed (removed) from the surface without adhering to the surface even if the soiled material adheres, is called “antifouling performance”. Shall be called. A coating composition (coating film) that can make the surface of the article excellent in antifouling performance by coating the surface of the article is a coating composition (coating film) having high antifouling performance or excellent antifouling performance. It shall be expressed. Here, adhesion refers to a state where it can be removed relatively easily from the surface, including a state where it is simply placed on the surface, and sticking refers to a state where it cannot be easily removed from the surface. As used separately.

  The pollutants that cause dirt include a hydrophilic stain 90 and a hydrophobic stain 91. The hydrophilic fouling substance 90 is likely to adhere to a portion showing hydrophilicity and difficult to adhere to a portion showing hydrophobicity. And the hydrophobic fouling substance 91 becomes the reverse. The hydrophilic fouling substance 90 is dust, dust, or the like. The hydrophilic fouling substance 90 and the hydrophilic fouling substance 90 are electrostatically bonded to each other by hydrophilic groups (OH groups) present in the hydrophilic portion of the article surface, or the hydrophilic fouling substance 90 The substance 90 adheres to the hydrophilic portion on the surface of the article (including the coating film surface) by intermolecular force due to the proximity of the hydrophilic portion on the article surface, or by liquid crosslinking with a liquid such as water interposed.

  Sand dust, which is a hydrophilic fouling substance 90 floating in the air, is a fine particle having a size of several μm to several tens of μm. Moreover, the dust which is also the hydrophilic fouling substance 90 is much larger than sand dust, and has a size of 0.1 mm to 5 mm. In order for such a hydrophilic fouling substance 90 to adhere to the hydrophilic portion on the surface of the article by the above-described action, the hydrophilic fouling substance 90 and the hydrophilic portion on the article surface can be sufficiently adhered (can be contacted). ) Only hydrophilic area must be present.

  However, since the coating film 103 formed by the coating composition 200 of this embodiment is dispersed with the fluororesin particles 102 exhibiting hydrophobicity moderately dispersed in the silica film 104 exhibiting hydrophilicity, In addition, there is almost no surface of the silica film 104 having a continuous area enough for the hydrophilic fouling substance 90 to stably adhere. The hydrophilic fouling substance 90 adhering onto the coating film 103 is caused by the hydrophobicity of the surface of the fluororesin particles 102 protruding (exposed) from the silica film 104 or the physical properties of the protruding fluororesin particles 102. Due to the inhibition, the surface of the silica film 104 cannot be sufficiently adhered. For this reason, the hydrophilic fouling substance 90 is easily detached and does not adhere to the coating film 103.

  Further, the silica film 104 is composed of silica fine particles 101 (the role of the binder is also played by the silica component of the silica fine particles 101), and is a porous film having fine voids between the silica fine particles 101, so the density is small. Even if the hydrophilic fouling substance 90 comes close, the intermolecular force is small and it is difficult to fix the hydrophilic fouling substance 90.

  Furthermore, since the porous silica film 104 has fine voids between the silica fine particles 101, even if liquid crosslinking with water or the like occurs, the water between the hydrophilic fouling substance 90 and the surface of the silica film 104 is Since it is removed through fine voids in the silica film 104 and liquid cross-linking is lost, the hydrophilic fouling substance 90 is not fixed by liquid cross-linking.

  As described above, the coating film 103 formed by the coating composition 200 exhibits excellent antifouling performance against the hydrophilic fouling substance 90.

  If the amount of the silica fine particles 101 in the coating composition 200 is greater than 95: 5 by weight ratio of the silica fine particles 101 and the fluororesin particles 102, the fluororesin particles 102 scattered in the silica film 104 in the coating film 103. An exposed surface portion having an area in which the hydrophilic fouling substance 90 having a small size such as a minute sand dust can be stably fixed appears on the silica film 104 due to an increase in the interval, and the hydrophilic fouling substance 90 is exposed on the surface of the silica film 104. There is a possibility of sticking to. Even if the amount of the silica fine particles 101 in the coating composition 200 is 100: 0 in terms of the weight ratio of the silica fine particles 101 and the fluororesin particles 102, a small effect on the hydrophobic soil can be expected.

  On the other hand, when the interval between the scattered fluororesin particles 102 is large and the continuous silica film 104 is wide without being blocked by the fluororesin particles 102, the hygroscopicity of the surface of the silica film 104 is improved. Since the charge to be charged easily leaks, there is an advantage that the charging of the surface of the coating film 103 can be efficiently suppressed. When the surface of the article is charged, fine suspended particles, which are fouling substances in the air, regardless of hydrophilicity or hydrophobicity, are attracted by electrostatic attraction and easily adhere to the article surface.

  In this coating composition 200, since the weight ratio of the silica fine particles 101 and the fluororesin particles 102 is 50:50 to 95: 5, in the silica film 104 of the coating film 103 formed with the coating composition 200 in this range. Has continuity that can suppress charging, that is, the fluororesin particles 102 are scattered at appropriate intervals such that the silica film 104 has a continuous area that can leak charges, and floating particles (fouling substances) due to charging. ). By coating the surface of the article with the coating composition 200 and forming the coating film 103 on the surface, dirt derived from static electricity can be prevented. Moreover, the dirt peelability from the filter vent 41 is also improved.

  If the amount of the silica fine particles 101 in the coating composition 3 is less than 50:50 in terms of the weight ratio of the silica fine particles 101 and the fluororesin particles 102, the interval at which the fluororesin particles 102 are scattered in the silica film 104 becomes narrow. Thus, it becomes difficult to obtain the effect of suppressing charging by the continuous silica film 104 as described above, and thereby the effect of preventing dirt derived from static electricity, and the antifouling performance is inferior.

  The hydrophobic fouling substance 91, which is another fouling substance, is oil smoke, carbon, cigarette dust, etc., and those that cause fouling are those floating in the air as fine particles. The particle diameter is 5 μm or less, and most are 0.1 to 0.3 μm, which is smaller than the hydrophilic fouling substance 90. The hydrophobic fouling substance 91 is difficult to adhere to the surface portion exhibiting hydrophilicity due to the presence of hydrophilic groups and adsorbed moisture on the surface, and easily adheres to the surface portion exhibiting hydrophobicity. The reason why the hydrophobic fouling substance 91 adheres to the surface of the article is due to the intermolecular force generated when the hydrophobic fouling substance 91 adheres to the surface portion exhibiting hydrophobicity.

  In the coating composition 200, the hydrophobic resin is the fluororesin particle 102 having an average particle diameter of 50 to 500 nm as described above. In the coating film 103 formed on the surface of the article, the fluororesin particles 102 may be larger than a single particle size due to deformation or coalescence, but the size of the hydrophobic fouling substance 91 that causes contamination is large. In many cases, the fluororesin particle 102 having a surface portion exhibiting hydrophobicity that is equal to or smaller than the above does not have an area where the hydrophobic fouling substance 91 can be sufficiently adhered.

  In such a case, intermolecular forces that are fixed to each other do not act, and the hydrophobic fouling substance 91 is difficult to be fixed to the fluororesin particles 102 exhibiting hydrophobicity. Naturally, since the hydrophobic fouling substance 91 does not adhere to the hydrophilic silica film 104, the coating film 103 also exhibits high antifouling performance against the hydrophobic fouling substance.

  Since the size (particle diameter) of the fluororesin particles 102 as described above is equal to or smaller than the size of the hydrophobic fouling substance 91, the hydrophobic fouling substance 91 is sufficient for the fluororesin particles 102 of the coating film 103. The hydrophobic fouling substance 91 is partly adhered to the fluororesin particle 102 and is partly adhered by the action of the intermolecular force. there is a possibility. Further, the hydrophobic fouling substance 91 may be smaller than the fluororesin particles 102, and it is possible that the fluororesin particles 102 have an area where they can sufficiently adhere to each other.

  However, the coating film 103 has another function of preventing the hydrophobic fouling substance 91 from adhering to the fluororesin particles 102 in addition to the above, and such partial adhering, adhering of the small hydrophobic fouling substance 91 is performed. Even make it difficult to happen. The operation will be described below.

  The fluororesin particles 102 of the coating composition 200 depend on the surfactant added during polymerization of the fluororesin, in a dispersion in water, and in a coating solution mixed with the dispersion of silica fine particles 101. The surface is in a hydrophilic state. When the coating film 103 is dried, the surfactant is peeled off and the surface of the fluororesin particles 102 becomes hydrophobic, but the silica fine particles 101 coexist in the coating solution. Therefore, the silica fine particles 101 having a smaller particle diameter than the fluororesin particles 102 are sparsely attached to the surface of the fluororesin particles 102 of the coating film 103 formed after drying.

  As described above, since the silica fine particles 101 having hydrophilic groups (showing hydrophilicity) are scattered and adhered to the surface of the fluororesin particles 102, the surface of the fluororesin particles 102 is partially covered with the hydrophobic fouling substance 91. Therefore, the hydrophobic fouling substance 91 smaller than the fluororesin particles 102 is less likely to adhere. By partially introducing a hydrophilic group onto the surface of the fluororesin particle 102, an effect of suppressing the adhesion between the fluororesin particle 102 and the hydrophobic fouling substance 91 can be obtained. Even if the hydrophobic fouling substance 91 adheres to the surface of the fluororesin particles 102, the silica fine particles 101 are scattered and attached, so that the attachment is unstable and can be easily detached.

  On the other hand, even on the surface of the fluororesin particle 102 on which the silica fine particles 101 are sparsely adhered, the hydrophilic fouling substance 90 which is much larger than the size of the silica fine particles 101 is sufficient. Therefore, the hydrophilic fouling substance 90 does not adhere to the surface of the fluororesin particle 102. In addition, the fluororesin particles 102 have a flexible surface, but when the silica fine particles 101 are sparsely attached in this way, the surface of the fluororesin particles 102 becomes hard and the hydrophobic fouling substance 5 adheres. The effect which becomes difficult to do is also acquired.

  In addition, the fluororesin itself has a very low surface energy and a low coefficient of friction, as is well known in the fluororesin coating, so that it not only exhibits hydrophobicity but also has oil repellency. Compared to a hydrophobic resin, the hydrophobic fouling substance 91 is less likely to stick. This is also one of the effects that the hydrophobic fouling substance 91 does not adhere to the fluororesin particles 102.

  Thus, the coating film 103 formed by the coating composition 200 also exhibits excellent antifouling performance against the hydrophobic fouling substance 91.

  When the amount of the fluororesin particles 102 in the coating composition 200 is greater than 50:50 by weight ratio of the silica fine particles 101 and the fluororesin particles 102, the portion of the fluororesin particles 102 exposed in the coating film 103 that exhibits hydrophobicity is exposed. The surface area becomes too large, and the tendency for the hydrophobic fouling substance 91 to adhere to the coating film 103 tends to increase. Then, due to the presence of a large number of fluororesin particles 102, some of them coalesce, and the coating film 103 becomes cloudy, thereby impairing the color tone and texture of the surface of the object to be coated. Further, when the fluororesin particles 102 are united, the continuity of the silica film 104 is hindered.

  When the thickness of the silica film 104 is larger (thicker) than the particle diameter of the fluororesin particles 102, the silica film 104 exhibiting new water is widely exposed as the surface of the coating film 103, and thus hydrophilic. The antifouling performance against the fouling substance 90 is inferior. Further, the dispersion of the fluororesin particles 102 in the silica film 104 is inhibited, the fluororesin particles 102 are separated from the silica film 104 and deposited on the surface of the silica film 104, and the fluororesin particles 102 are united to form a lump. Therefore, it is possible that the fresh water is locally deteriorated at that portion or the hydrophobic fouling substance 91 is fixed. Therefore, as described above, the thickness of the silica film 104 is smaller (thinner) than the average particle diameter of the fluororesin particles 102, and the fluororesin particles 102 are appropriately dispersed in the silica film 104. The resin particles 102 can be partially exposed from the silica film 104 instead of the whole.

  As the fluororesin particles 102 in the coating composition 200, PTFE (polytetrafluoroethylene), FEP (tetrafluoroethylene / hexafluoropropylene copolymer), PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), ETFE (ethylene / tetrafluoroethylene copolymer), ECTFE (ethylene / chlorotrifluoroethylene copolymer), PVDF (polyvinylidene fluoride), PCTFE (polychlorotrifluoroethylene), PVF (polyvinyl fluoride), etc. These copolymers or mixtures, or those obtained by mixing these with other resins can be used.

  The fluororesin particles 102 need to be in the state of a dispersion dispersed in water before the coating composition 200 is manufactured. The dispersing method can be performed by using fluororesin particles 102 polymerized by suspension polymerization or emulsion polymerization and using a surfactant. In the state dispersed in water, the surface of the fluororesin particles 102 is in a state of low hydrophobicity, but the surface is hydrophobic in the state of being dried to form a solid (coating film 103). What should I do? As the fluororesin used, PTFE and FEP are particularly excellent in stability that they do not aggregate in the dispersion or coating solution, and also have a high hydrophobicity when dried to form the coating film 103. To preferred.

  As described above, the coating film 103 formed on the surface of the article by the coating composition 200 does not fix both the hydrophilic fouling substance 90 and the hydrophobic fouling substance 91, and can be easily detached even if attached. Therefore, excellent antifouling performance and releasability can be exhibited, and contamination of the coated filter surface can be prevented. Also in examples (experimental results) described later, it is proved that the antifouling performance of the coating composition 200 according to this embodiment is excellent.

  The manufacturing method of the coating composition 200 of this embodiment is not particularly limited, but can be easily manufactured by mixing the dispersion of the silica fine particles 101 and the dispersion of the fluororesin particles 102. Can do. Here, as the dispersion liquid of the silica fine particles 101, one in which the silica fine particles 101 having an average particle diameter of 15 nm or less are dispersed in water, for example, commercially available colloidal silica can be used. In the dispersion of the silica fine particles 101, the volume ratio of the silica fine particles 101 in the dispersion is preferably 20% or less. This is because if the volume ratio exceeds 20%, the stability of the dispersion liquid may be deteriorated, for example, the silica fine particles 101 may be aggregated.

  Further, as the dispersion liquid of the fluororesin particles 102, a dispersion in which the fluororesin particles 102 having an average particle diameter of 500 nm or less are dispersed in water, for example, PTFE dispersion can be used. In order to uniformly disperse the hydrophobic fluororesin particles 102 in the coating composition 200, a surfactant may be added. In either dispersion, the polar solvent is not limited to water.

  The water used in each dispersion is not particularly limited, but ionic properties such as calcium ions and magnesium ions are used to disperse and stabilize the silica fine particles 101 and the fluororesin particles 102 without agglomeration. The thing with few impurities is good. The divalent or higher ionic impurity is desirably 200 ppm or less, and more desirably 50 ppm or less. If divalent or higher ionic impurities increase, the silica fine particles 101 and the fluororesin particles 102 may aggregate and precipitate, or the strength and transparency of the coating film 103 to be formed may decrease.

  Since this coating composition 200 does not contain an organic solvent, it is safe and environmentally friendly. Moreover, since it can manufacture only by mixing the dispersion liquid marketed as mentioned above, there exists an advantage which can be manufactured easily at low cost.

  However, the coating composition 200 can ensure the stability of the hydrophobic fluororesin particles 102, improve the adhesion of the coating film 103 to be formed, and adjust the hydrophilicity of the coating film 103 according to the material of the article to be coated. From the viewpoint of achieving this, a surfactant or an organic solvent may be added. In addition, a coupling agent or a silane compound may be added to the coating composition 200 for the purpose of improving the adhesion, transparency, and strength of the coating film 103 to be formed, and adjusting the hydrophilicity of the coating film 103. .

  Here, examples of the surfactant that can be used in the coating composition 200 include various anionic or nonionic surfactants. Among such surfactants, polyoxypropylene-polyoxyethylene block polymers, polycarboxylic acid type anionic surfactants and the like are preferable because they have low foaming properties and are easy to use.

  Examples of the organic solvent that can be used in the coating composition 200 include various alcohol-based, glycol-based, ester-based, and ether-based solvents.

  Further, examples of the coupling agent that can be used for the coating composition 200 include amino-based compounds such as 3- (2-aminoethyl) aminopropyltrimethoxysilane, and epoxy-based compounds such as 3-glycidoxypropyltrimethoxysilane, 3 -Methacryloxy type such as methacryloxypropylmethyldimethoxysilane, mercapto type, sulfide type, vinyl type, ureido type and the like.

  Examples of the silane compound usable in the coating composition 200 include halogen-containing materials such as trifluoropropyltrimethoxysilane and methyltrichlorosilane, alkyl group-containing materials such as dimethyldimethoxysilane and methyltrimethoxysilane, 1,1 , 1,3,3,3-hexamethyldisilazane and the like, and oligomers such as methylmethoxysiloxane.

  The content of the above additives is not particularly limited as long as it does not impair the antifouling performance, initial hydrophilicity, and long-term hydrophilic sustainability of the coating composition 200, and depends on the selected additive. May be adjusted accordingly.

  The method of coating the surface of the article with the coating composition 200 of this embodiment is not particularly limited, and can be performed using a conventionally known method, but the coating composition 200 is coated. A method of removing the excess coating composition 200 with an air flow after application to the surface of the article is desirable. If the excessive coating composition 200 stays on the surface of the article, the coating film 103 formed on the surface becomes thick, and the silica film 104 is easily cracked. There is a risk of damaging the color and texture of objects.

  Moreover, in order to dry the excess coating composition 200, drying time will increase. The increase in the drying time is not only undesirable in the manufacturing process of the article, but the fluororesin particles 102 accumulate at the air interface during drying, and the resulting coating film 103 becomes more hydrophobic, and the hydrophobic fouling substance 91 There is a risk that it becomes difficult to adhere and a high antifouling property cannot be obtained. If it is a method of removing the excess coating composition 200 with an air stream, not only the excess coating composition 200 is removed, but also an effect of promoting drying by the air stream is obtained, and the fluororesin particles 102 are contained in the silica film 104. There is also an advantage that a good coating film 103 which is moderately scattered can be obtained.

  Thus, when the excess coating composition 200 is removed from the surface of the article to be coated by airflow, the temperature of the airflow is 110 ° C. or less, desirably 90 ° C. or less. If the temperature of the air stream is too high, the hydrophobicity of the coating film 103 formed by the alteration of the silica film 104 tends to be strong, and the hydrophobic fouling substance 91 is liable to stick, which is not preferable. As for the lower limit of the temperature of the air flow, if it is 35 ° C. or lower, the drying time becomes long, and as described above, the hydrophobicity of the coating film 103 obtained may be increased in the manufacturing process, which is not preferable.

  The time for blowing the airflow is not limited because it depends on the temperature of the airflow and the shape of the article to be coated, but it is preferably 2 seconds or more and 20 seconds or less for an article having a simple shape. For an article having a complicated shape having minute gaps or holes, it is preferably 5 seconds or more and 50 seconds or less. If the time is short, the excess coating composition 200 is likely to remain, and if the time is too long, as described above, not only the manufacturing process but also the possibility that the hydrophobicity of the coating film 103 may become strong is not preferable. .

  The method of applying the coating composition 200 of this embodiment to the surface of the object to be coated is not particularly limited, but when performed by a method of covering the surface of the article with the coating composition 200 such as dipping or coating, There is no uncoated portion, and a uniform coating film 103 with less unevenness in thickness can be formed, which is preferable. In the dipping or spraying method, the surface of the article can be covered with the coating composition 200 without any defects.

  In order to make the coating film 103 with less unevenness in thickness, the above-described method of removing the excess coating composition 200 with an air flow is also preferable, but in the case of immersion, the article to be coated is removed from the coating solution (coating composition 200). The excess coating composition 200 is removed by removing the excess coating composition 200 by slowly pulling down the coating solution and suppressing unevenness. In the case of dipping or spraying, the coated article 200 is rotated. Also preferred is a method of removing by shaking.

  Depending on the article to be coated with the coating composition 200, the surface of the article may be subjected to corona treatment in advance from the viewpoint of improving the hydrophilicity and adhesion of the coating film 103 formed on the article surface by drying the coating composition 200. Further, pretreatment such as UV treatment may be performed. In the coating composition 200 of this embodiment, since the silica fine particles 101 are solidified only by drying, the fluororesin particles 102 can be exposed on the surface of the coating film 103 without requiring heating or the like.

  Hereinafter, detailed experimental results and characteristics of the coating composition 200 of this embodiment will be described by showing specific examples. The following examples do not limit the scope of this embodiment. As a test object for coating and forming a coating film on the surface, PET (polyethylene terephthalate) fiber for filter is used.

Examples 1-7.
In Examples 1 to 7, colloidal silica (catalyst chemical industry Co., Ltd., pH 10) in which silica fine particles having an average particle diameter of 6 nm are dispersed in pure water, and PTFE disperser in which fluororesin particles having an average particle diameter of 150 nm are dispersed in pure water. After stirring and mixing with John (manufactured by Asahi Glass Co., Ltd., pH 10), a nonionic surfactant (polyoxyethylene alkyl ester) is further added and mixed by stirring to obtain a coating composition having the composition shown in FIG. Prepared. The content of the nonionic surfactant in the coating composition was 0.05% by weight. These coated the surface of the test piece. Further, in order to find the optimum weight ratio between the silica fine particles and the fluororesin particles, the weight ratio between the silica fine particles and the fluororesin particles was changed in the range of 30:70 to 100: 0.

Comparative Examples 1-4.
Comparative Example 1 is an uncoated PET filter conventionally used in the air conditioner 100, and does not contain silica or fluorine. In Comparative Example 2, a metal stainless steel coating was applied to the filter surface by sputtering. In Comparative Example 3, the fluorine coating was applied only with the fluororesin. In Comparative Example 4, the weight ratio was the same as that of Example 6, but the weight ratio of silica fine particles to the coating composition was increased, that is, the concentration of fine particles was increased to prepare the coating composition. Details are shown in FIG.

  The coating composition of each example was applied to the test piece, and a coating film was formed on the test piece by blowing off excess liquid by air blow, and the properties, initial contact angle θ and antifouling performance of the formed coating film were each shown. evaluated. The air blow was performed at a flow rate of 30 m / s. Here, the properties of the coating film were evaluated by visual observation. The contact angle θ was measured with a contact angle meter (DM100 manufactured by Kyowa Interface Chemical Co., Ltd.). The antifouling performance was evaluated for the adhesion of sand dust, which is a hydrophilic fouling substance, and for carbon dust, which is a hydrophobic fouling substance.

  The sticking evaluation of the hydrophilic fouling substance 90 is performed by visually observing the coloring caused by the sticking of red Kanto loam dust by spraying JIS Kanto loam dust having a central particle size of 1 to 3 μm on the coating surface (coating film) with air. Was evaluated in five stages. In this evaluation, 1 indicates that the Kanto loam dust is hardly fixed, and 5 indicates that the Kanto loam dust is largely fixed. In addition, the sticking evaluation of the hydrophobic fouling substance 91 was performed by visually observing the coloring due to the sticking of the black carbon black by spraying oil-based carbon black onto the coating surface (coating film) with air. In this evaluation, 1 indicates that carbon black is hardly fixed, and 5 indicates that carbon black is largely fixed. The evaluation results are shown in FIG.

  From the experimental results shown in FIG. 10, the coating films formed by the coating compositions of Examples 1 to 7 all showed excellent antifouling performance against both hydrophilic and hydrophobic fouling substances, and the silica fine particles By adjusting the content (weight ratio) of 101 and the fluororesin particles 102, the macroscopic characteristics (hydrophilicity or hydrophobicity) of the formed coating film could be adjusted. Since the coating film of this embodiment is based on a continuously connected hydrophilic silica film, the contact angle θ generally shows a low value, but in the micro region (microscopically), the hydrophilic The hydrophobicity is alternately arranged continuously at the nano level. Further, when the proportion of silica is increased, adhesion of the hydrophobic fouling substance 91 can be suppressed, and when the proportion of fluorine is increased, adhesion of the hydrophilic fouling substance 90 can be suppressed.

  However, in Example 1 where the weight ratio of the fluororesin particles 102 is high (weight of silica fine particles 101: weight of fluororesin particles 102 = 30: 70), the antifouling performance against the hydrophobic fouling substance 91 tends to be slightly inferior. I understand. Further, Example 7 (weight of silica fine particles 101: weight of fluororesin particles 102 = 100: 0) formed only of silica fine particles 101 has an antifouling effect only on the hydrophobic fouling substance 91, and the fluororesin Since there is no minute unevenness due to the particles 102, the adhesion area is wide, and the overall antifouling effect is considerably limited.

  In the coating compositions 200 of Examples 1 to 7, a thin coating film having a uniform thickness could be formed. Example 5 was slightly cloudy, but otherwise a transparent film could be formed. Comparing Example 6 and Comparative Example 4, it can be seen that the properties of the film change even with the same weight ratio of silica fine particles 101 and fluororesin particles 102. When the content (concentration) of the silica fine particles 101 is high (exceeding 5% by weight), the coating film to be formed is not preferable because it is non-uniform in thickness and easily clouded.

  Example 2 in which the weight ratio of the fluororesin particles 102 to the silica fine particles 101 is in the range of 50:50 to 85:15 as having both antifouling performance for both hydrophilic and hydrophobic fouling substances. 5 is particularly preferred. More specifically, Example 4 having a weight ratio of 75:25 is most preferable, and the filter 40 can be effectively protected from contamination of both hydrophilic and hydrophobic particles. By adjusting the content (weight ratio) of the silica fine particles 101 and the fluororesin particles 102, the antifouling property can be easily controlled.

On the other hand, in the conventional PET filter (PET fiber) of Comparative Example 1 with no coating used for the air conditioner 100, it was shown that all the stains clearly adhered to 5 points and were easily damaged. In order to know the antifouling effect in absolute value, PET film was separately sprayed with Kanto Loam dust and carbon black and evaluated from light transmittance. As a result, Example 4 (weight ratio of silica fine particles 101 and fluororesin particles 102 of 75:25) adheres to about 1/20 in both hydrophilicity and hydrophobicity compared to the case where conventional coating is not applied. The amount can be suppressed. The surface resistance (volume resistivity) of the PET fiber of Comparative Example 1 is as high as about 10 ¹⁶ Ω · cm, whereas the surface resistance (volume resistivity) of the coatings of Examples 1 to 7 is about Since it shows a low value of 10 ¹² Ω · cm, the electrostatic force on the surface is lower than that of conventional PET fibers, and the attached dirt is easily peeled off. This is because the coating according to the present embodiment is macroscopically hydrophilic, so that ionic conduction is promoted by the OH group on the surface, and electricity easily passes.

  By preventing the filter vent 41 (PET fiber) from adhering to the filter vent 41 (PET fiber), it is difficult for the dust to separate from the filter 40 when scraping with the roll brush 71, and the roll brush 71 is a mesh of the filter 40. It is possible to avoid such a problem that the filter 40 is clogged despite the presence of the filter cleaning device 50. As a result, the long-term reliability of the filter cleaning device 50 can be obtained, and the filter 40 can be kept clean for a long time.

Both the stainless steel coating of Comparative Example 2 and the fluorine coating with the fluororesin of Comparative Example 3 showed a certain antifouling effect against hydrophilic dirt, but the degree of dirt was high against hydrophobic dirt. . Due to the binder effect of these hydrophobic fouling substances 91, long fiber dust and lint that pass through later adhere to the filter and become difficult to separate. Further, stainless steel coating of Comparative Example 2 is that the density is about 7~8g / cm ^3, the density of the coating of Example 1-7 is 0.2 to 0.7 g / cm ³ molecule The interstitial force is lower than that of the metal coating, and the attached dirt is easily peeled off.

  Finally, carbon black was used as a representative of hydrophobic particles, but the influence of oil smoke, which is another hydrophobic fouling substance 91, was confirmed. Oil smoke emitted from yakiniku is set to a filter front wind speed of 1 m / s and passed through the filter 40 of Example 4 and the conventional filter 40 of Comparative Examples 1 to 3 which are installed in a 20 cm square wind tunnel, and the degree of oil smoke adhesion is visually and microscopically observed. And observed. Each filter 40 has a side of 0.6 mm. Then, the fiber dust of 0.5 mm or less smaller than the mesh size of the filter 40 was passed. As a result, in Example 4, it was clearly shown that the amount of dust adhered was small, and the adhesion of oil smoke was suppressed. This is because, in addition to the effect that the adhesion area of the hydrophobic particles is small, the film has a low density, so even if oil smoke adheres, it is absorbed inside the coating, so that oil smoke does not remain on the surface. In addition, the effect of dust peeling off over time was also confirmed. On the other hand, in the conventional filters 40 of Comparative Examples 2 to 4, oil smoke adhesion was clearly confirmed on the filter fiber, the fiber dust capture rate was improved, and the dust was difficult to peel off from the filter fiber over time.

  So far, the effect of coating the filter 40 has been shown, but there is also a risk that the roll-shaped brush 71 also develops abnormal operation due to dust adhering thereto. The coating composition 200 shown in the present embodiment has an antifouling effect when applied not only to the filter 40 but also to the roll-shaped brush 71, and air having a filter cleaning device 50 that automatically cleans the filter 40. The long-term reliability of the harmony machine 100 can be improved.

  As described above, the filter cleaning device 50 according to the present embodiment includes the dust removing unit 70 that removes the dust trapped by the filter 40, and the coating composition 200 on the surface of the filter 40 includes the silica fine particles 101. And the fluororesin particles 102, and the coating film is interspersed in the silica film 104 composed of the silica fine particles 101 so that the fluororesin particles 102 are partially exposed from the surface of the silica film 104. The exposed area of the film 104 is larger than the exposed area of the fluororesin particles 102, and the average film thickness of the silica film 104 is smaller than the average particle diameter of the fluororesin particles 102. Thereby, while exhibiting the excellent antifouling performance with respect to both the hydrophilic fouling substance 90 and the hydrophobic fouling substance 91, there exists an effect which exhibits favorable peelability with the low intermolecular force and the low electrostatic force, and filter cleaning The filter 50 prevents clogging of the filter 40 by reducing dust spreading and removal by the device 50. As a result, the reduction in airflow is suppressed, the cooling / heating capacity is lowered, the heating airflow is insufficient to reach the floor, the heating airflow soars, discomfort due to cooling airflow, the generation of abnormal noise due to reverse suction near the blowout, It is intended to prevent various adverse effects such as deterioration.

Embodiment 2. FIG.
In the first embodiment, the air conditioner 100 including the filter cleaning device 50 has been described as an example. However, the surface of the filter 40 of the air conditioner 100 that does not have the filter cleaning device 50 is the same as that of the first embodiment. The coating composition 200 may be coated, and the coating composition 200 exhibits excellent antifouling performance against both the hydrophilic fouling substance 90 and the hydrophobic fouling substance 91, thereby preventing clogging of the filter 40. be able to.

  11 and 12 are diagrams showing the second embodiment. FIG. 11 is a cross-sectional view at a substantially central portion in a side view schematically showing the air conditioner 100. FIG. 12 is a perspective view schematically showing the filter 40. is there.

  The air conditioner 100 shown in FIG. 11 does not have the filter cleaning device 50 that automatically cleans the filter 40. The filter 40 is cleaned by the user of the air conditioner 100 taking out the filter 40 from the air conditioner 100.

  The user of the air conditioner 100 takes out the filter 40 from the air conditioner 100 by opening the front door 12 and pulling out the filter 40 from the lower edge 47 side.

  The filter 40 shown in FIG. 12 does not include the filter driven gear shown in FIG. 2 because the air conditioner 100 does not have the filter cleaning device 50.

  Further, the length of the filter 40 from the upper edge 46 to the lower edge 47 is longer than that of the filter 40 shown in FIG. The length of the filter 40 substantially covers the upper surface and the front surface of the heat exchanger 30.

  As in the first embodiment, the coating composition 200 is coated on the surface of the filter 40. The coating composition 200 contains silica fine particles 101 and fluororesin particles 102 so that the fluororesin particles 102 are partially exposed from the surface of the silica film 104 in the silica film 104 composed of the silica fine particles 101. The exposed area of the silica film 104 is larger than the exposed area of the fluororesin particles 102, and the average film thickness of the silica film 104 is smaller than the average particle diameter of the fluororesin particles 102.

  By coating the coating composition 200 on the surface of the filter 40, excellent antifouling performance is exerted against both the hydrophilic fouling substance 90 and the hydrophobic fouling substance 91, so that the filter 40 is prevented from being clogged. be able to.

  Therefore, the frequency of cleaning of the filter 40 performed by the user of the air conditioner 100 by taking out the filter 40 from the air conditioner 100 is significantly higher than that of the air conditioner 100 in which the coating composition 200 is not coated on the conventional filter 40. decrease.

  Further, the cleaning of the filter 40 performed by the user of the air conditioner 100 is a molecule in which the coating composition 200 coated on the surface of the filter 40 is low in both the hydrophilic fouling substance 90 and the hydrophobic fouling substance 91. Due to the effect of exhibiting good releasability due to the intermediate force and the low electrostatic force, it is much easier than the filter 40 not coated with the conventional coating composition 200.

Sectional drawing in the approximate center part of the side view which shows the air conditioner 100 which concerns on Embodiment 1 typically. The perspective view which shows the filter 40 of FIG. 1 typically. FIG. 5 shows the first embodiment and is a detailed view of the filter vent 41. FIG. FIG. 5 shows the first embodiment, and is a diagram showing the relationship between the clogging of the filter 40 and the degree of deterioration of electricity cost. FIG. 4 is a diagram showing the first embodiment, and is a perspective view schematically showing a dust removing unit 70. FIG. FIG. 3 is a diagram illustrating the first embodiment, and is a conceptual diagram illustrating a cross section in a state where a coating composition 200 is coated on the surface of the filter 40 and a coating film is formed. FIG. 2 is a diagram showing the first embodiment, and is a conceptual diagram showing only a portion of a coating film 103 made of a coating composition 200. FIG. 3 is a diagram illustrating the first embodiment and is a conceptual diagram when an upper surface of a coating film 103 is viewed. The figure which shows the composition of the coating of Examples 1-7 and Comparative Examples 1-4. The figure which shows the result of having evaluated the property of the coating film of Examples 1-7 and Comparative Examples 1-4, initial contact angle (theta), and antifouling performance, respectively. FIG. 5 shows the second embodiment, and is a cross-sectional view at a substantially central portion in a side view schematically showing the air conditioner 100. FIG. 9 is a diagram illustrating the second embodiment and is a perspective view schematically illustrating a filter 40.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Housing | casing, 11 Inlet, 12 Front door, 13 Nozzle, 14 Air outlet, 15 Rear guide plate, 16 Wall mounting part, 17 Arc-shaped moving path, 20 Blower, 30 Heat exchanger, 31 Heat exchanger tube, 32 Heat radiation Fin, 40 Filter, 41 Filter ventilation body, 42 Filter frame, 43 Outer frame, 44 Reinforcement bar, 45 Filter driven gear, 46 Upper edge, 47 Lower edge, 50 Filter cleaning device, 60 Filter moving part, 61 Filter drive gear , 62 Filter drive shaft, 64 Filter moving body, 70 Dust remover, 71 Roll brush, 72 Roll brush drive shaft, 73 Roll brush rotation input gear, 74 Dust remover body, 75 Shaft support protrusion, 80 Dust Collection unit, 81 scraping plate, 82 urging means, 83 dust collection box, 90 hydrophilic pollutant, 91 hydrophobic pollutant , 100 air conditioner, 101 silica fine particles, 102 fluororesin particles, 103 a coating film, 104 a silica film, 107 filter fibers, 200 coating composition.

Claims (8)

A filter frame;
A mesh-like filter vent installed in the filter frame;
A coating film is formed on the surface of the filter ventilation body, and contains silica fine particles and fluororesin particles. The coating film is formed in the silica film composed of the silica fine particles, and the fluororesin particles are exposed from the surface of the silica film. A filter comprising: a coating composition which is interspersed so as to be partially exposed, and wherein the exposed area of the silica film is larger than the exposed area of the fluororesin particles.   2. The filter according to claim 1, wherein the coating composition has a weight ratio of the content of the silica fine particles to the content of the fluororesin particles in a range of 30:70 to 95: 5. .   The filter according to claim 1 or 2, wherein the coating composition has an average particle diameter of the silica fine particles in a range of 4 to 15 nm.   4. The filter according to claim 1, wherein the coating composition has an average particle diameter of the fluororesin fine particles in a range of 50 to 500 nm.   5. The filter according to claim 1, wherein the content of the silica fine particles is 0.1 to 5% by weight with respect to the coating composition.   The filter according to any one of claims 1 to 5, wherein an average thickness of the silica film is smaller than an average particle diameter of the fluororesin particles in the coating film. A housing,
A blower fan installed in the housing for sucking air and blowing the sucked air;
A heat exchanger that is arranged in an air passage formed by the blower fan and that exchanges heat between the sucked air and a refrigerant in the refrigeration cycle;
A filter for capturing dust contained in the sucked air;
A filter cleaning device for cleaning the filter,
An air conditioner using the filter according to any one of claims 1 to 6 as the filter. A housing,
A blower fan installed in the housing for sucking air and blowing the sucked air;
A heat exchanger that is arranged in an air passage formed by the blower fan and that exchanges heat between the sucked air and a refrigerant in the refrigeration cycle;
And a filter that captures dust contained in the sucked air,
An air conditioner using the filter according to any one of claims 1 to 6 as the filter.

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