Aqueous coating composition and method for producing aqueous coating composition

Abstract

Provided are an aqueous coating composition capable of forming an ozone-decomposing coating film that reduces ozone concentration, and a method for producing the same. [Solution] The aqueous coating composition contains a solvent whose main component is water, a manganese oxide catalyst, activated carbon, a polyacrylate dispersant, a resin, and a pH adjuster.

Description

[Technical Field]

[0001] The present invention relates to an aqueous coating composition and a method for producing an aqueous coating composition. [Background technology]

[0002] Exhaust gases emitted from factories, automobiles, etc. contain nitrogen oxides (NO X Volatile organic compounds (VOCs) such as chlorofluorocarbons (CDs) and hydrocarbons (HCs) are produced by chemical reactions with oxygen in the atmosphere and photochemical reactions caused by ultraviolet rays from sunlight, resulting in photochemical oxidants (O x These photochemical oxidants are air pollutants whose main component is ozone (O3), i.e., substances of environmental concern, and cause photochemical smog.

[0003] In Japan, the environmental standard for photochemical oxidants is set at 0.06 ppm or less in one-hour values. However, the current situation is one in which the standard value continues to be exceeded, and with the increasing global awareness of global environmental conservation issues in recent years, there is a need for immediate measures to reduce photochemical oxidants.

[0004] Therefore, while regulating emissions of volatile organic compounds such as nitrogen oxides, technologies have been proposed to prevent the generation of photochemical smog by decomposing (purifying) the ozone that is produced. For example, in some areas of the United States, such as California, an air purification system is being considered that aims to improve the air quality by installing a radiator carrying an ozone-decomposing catalyst in a vehicle and running the vehicle, and automobiles using direct ozone reduction (DOR) technology, such as automobiles equipped with an air purification device for vehicles that can decompose ozone in the atmosphere using an ozone-decomposing catalyst (ozone purification catalyst), have been put into practical use. In particular, in California and other states, automobiles that incorporate such direct ozone reduction (DOR) technology and manufacturers that sell such vehicles are granted a specified benefit (NMOG credit certification) that is deemed to have reduced emissions of non-methane organic gases (NMOG), which are a cause of photochemical smog.

[0005] As a technology relating to a radiator carrying an ozone decomposition catalyst, for example, Patent Documents 1 and 2 disclose a technology of an air purification device for a vehicle in which a metal oxide catalyst is carried on the surface of the radiator (fins) into which air flows while the vehicle is running, and describe that ozone contained in the air is decomposed by an ozone decomposition catalyst layer on the surface of the radiator. Furthermore, Patent Document 3 proposes an air purification device for vehicles that uses not only a metal oxide catalyst but also activated carbon that has the function of purifying ozone. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 2002-514966 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-000746 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-024027 Summary of the Invention [Problem to be solved by the invention]

[0007] Thus, as shown in Patent Documents 1 to 3, technologies have been developed for vehicle air purification devices that purify ozone in the atmosphere by supporting a catalyst that decomposes ozone in the atmosphere on the surface of the radiator (fins), thereby purifying ozone in the atmosphere with an ozone decomposition catalyst layer provided on the surface of the radiator.

[0008] On the other hand, if fans, circulators, air conditioners, air purifiers, and other blowers had the ability to decompose ozone in the atmosphere and blow air with reduced ozone concentrations, they could make a significant contribution to purifying ozone in the atmosphere in indoor and outdoor facilities. For example, many agricultural and horticultural crops are highly sensitive to ozone, and ozone can cause various damage to the crops, resulting in reduced growth and yield. Therefore, a fan capable of decomposing atmospheric ozone can reduce ozone damage to agricultural and horticultural crops, both indoors and outdoors. Furthermore, since it has been reported that ozone has an effect on the human body, a fan having a function of decomposing ozone in the atmosphere can reduce the effect of ozone on the human body in indoor and outdoor facilities.

[0009] Furthermore, if ozone can be decomposed using items other than fans that have the function of decomposing ozone in the atmosphere, an environment with reduced ozone concentrations can be realized, thereby reducing the damage caused by ozone to agricultural and horticultural crops and the effects of ozone on the human body.

[0010] Therefore, an object of the present invention is to provide an aqueous coating composition capable of forming an ozone-decomposing coating film that reduces ozone concentration, and a method for producing the same. [Means for solving the problem]

[0011] In order to solve the above problem, the invention described in claim 1 is: The aqueous coating composition contains a solvent whose main component is water, a manganese oxide catalyst, activated carbon, a polyacrylate dispersant, a resin, and a pH adjuster. According to the invention of claim 1, the aqueous coating composition containing the above components can form an ozone-decomposing coating film having ozone-decomposing properties.

[0012] The invention described in claim 2 is as follows: 2. The aqueous coating composition according to claim 1, wherein the manganese oxide catalyst is a manganese dioxide catalyst. According to the invention described in claim 2, the manganese dioxide catalyst has high catalytic activity, the ozone decomposing ability of the ozone decomposing coating film is improved, and further, the ozone concentration is reduced.

[0013] The invention described in claim 3 is the aqueous coating composition described in claim 1 or claim 2, wherein the blending ratio of the manganese oxide catalyst to the activated carbon is 20 / 80≦activated carbon / manganese oxide catalyst≦80 / 20 by mass. According to the invention of claim 3, the ozone decomposing ability of the ozone decomposing coating film is improved and the ozone concentration is further reduced due to the synergistic effect of the ozone decomposing ability achieved by combining the manganese oxide catalyst and activated carbon.

[0014] The invention described in claim 4 is the aqueous coating composition described in any one of claims 1 to 3, wherein the total amount of the manganese oxide catalyst and the activated carbon is 60% by mass to 90% by mass relative to the cured film of the aqueous coating composition. According to the invention as set forth in claim 4, high ozone decomposition performance is imparted to the ozone decomposing coating film without impairing the adhesion of the ozone decomposing coating film, and the ozone concentration is continuously reduced.

[0015] Furthermore, the invention described in claim 5 is an aqueous coating composition described in any one of claims 1 to 4, wherein the polyacrylate-based dispersant is a dispersant having a weight average molecular weight in the range of 5,000 to 30,000, an acid value in the range of 1 to 50, and a hydrogen ion exponent in the range of pH 4 to pH 9. According to the invention as set forth in claim 5, high ozone decomposition performance is imparted to the ozone decomposing coating film without impairing the adhesion of the ozone decomposing coating film, and the ozone concentration is continuously reduced.

[0016] The invention described in claim 6 is an aqueous coating composition described in any one of claims 1 to 5, wherein the content of the polyacrylate dispersant is within the range of 1.5 to 75 parts by mass per 100 parts by mass of the total amount of the manganese oxide catalyst and the activated carbon. According to the sixth aspect of the present invention, the ozone decomposing coating film is endowed with high ozone decomposing performance, and the ozone concentration is further reduced.

[0017] The invention described in claim 7 is the aqueous coating composition described in any one of claims 1 to 6, wherein the resin is at least one selected from a (meth)acrylic resin and a polypropylene resin. According to the invention of claim 7, the use of a (meth)acrylic resin with excellent adhesion to metals improves the adhesion of the ozone-decomposable coating film to metal components (ventilation members, rotating blades, guide members, etc.), resulting in a continuous reduction in ozone concentration. Furthermore, the use of a polypropylene resin with excellent adhesion to metals and resins improves the adhesion of the ozone-decomposable coating film to metal and resin components (ventilation members, rotating blades, guide members, etc.), resulting in a continuous reduction in ozone concentration.

[0018] The invention described in claim 8 is characterized in that the degree of dispersion of the manganese oxide catalyst and the activated carbon measured by a grind gauge is greater than or equal to the maximum particle diameter (D max 8. The aqueous coating composition according to any one of claims 1 to 7, wherein the particle size is 20 μm or less. According to the invention of claim 8, a coating film formed from a coating composition in which a manganese oxide catalyst and activated carbon are highly dispersed in fine particles contains the manganese oxide catalyst and activated carbon with good dispersibility, and the amount of ozone adsorbed by the manganese oxide catalyst and activated carbon is increased, thereby demonstrating high ozone decomposition performance.

[0019] The invention described in claim 9 is characterized in that the manganese oxide catalyst and the activated carbon have a 90% cumulative particle diameter (D 909. The aqueous coating composition according to claim 1, wherein the particle size is 10 μm or less. According to the invention of claim 9, a coating film formed from a coating composition in which a manganese oxide catalyst and activated carbon are highly dispersed in fine particles contains the manganese oxide catalyst and activated carbon with good dispersibility, and the amount of ozone adsorbed by the manganese oxide catalyst and activated carbon is increased, thereby demonstrating high ozone decomposition performance.

[0020] The invention described in claim 10 is the aqueous coating composition according to any one of claims 1 to 9, wherein the activated carbon is powdered activated carbon. According to the invention described in claim 10, even if the activated carbon is in powder form, the aqueous coating composition containing the above components can form an ozone-decomposing coating film having ozone-decomposing properties.

[0021] In addition, the invention described in claim 11 is characterized in that the specific surface area of ​​the activated carbon measured by the BET method of N2 adsorption is 500m 2 / g~3000m 2 The aqueous coating composition according to any one of claims 1 to 10, wherein the content of the water-based coating composition is 1 / g. According to the invention of claim 11, the ozone-decomposing coating film has good film-forming and adhesion properties, the catalyst is less likely to fall off, and high ozone decomposing performance can be obtained more effectively and sustainably. In addition, the coating composition has good storage stability.

[0022] The invention described in claim 12 is as follows: a dispersing step of mixing and dispersing a water-based solvent, a manganese oxide catalyst, activated carbon, and a polyacrylate dispersant; a neutralization step of mixing a pH adjuster with the dispersed mixture; a coating process of mixing a resin with the neutralized mixture; The present invention relates to a method for producing an aqueous coating composition comprising the steps of: According to the invention as set forth in claim 12, it is possible to produce an aqueous coating composition capable of forming an ozone-decomposing coating film having ozone-decomposing properties. [Effects of the Invention]

[0023] According to the present invention, it is possible to provide an aqueous coating composition capable of forming an ozone-decomposing coating film that reduces ozone concentration, and a method for producing the same. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic exploded perspective view showing an example of a blower according to this embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view showing the periphery of the blower according to this embodiment. [Figure 3] FIG. 3 is a schematic plan view showing filter members provided as the first ventilation member and the second ventilation member in the blower according to the present embodiment. [Figure 4] FIG. 4 is a schematic diagram for explaining the method of the ozone decomposition evaluation test in the test examples and comparative examples shown in Tables 1, 2 and 4. [Figure 5] FIG. 5 is a schematic diagram for explaining the method of the ozone decomposition evaluation test in the test examples and comparative examples shown in Table 3. [Figure 6] FIG. 6 is a schematic diagram showing an example of a building having an air conditioning system according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, an embodiment of the present invention will be described. In this specification, components having substantially the same functions are denoted by the same reference numerals throughout the drawings, and redundant explanations may be omitted. A numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. In numerical ranges described in stages, the upper limit value described in one numerical range may be replaced with the upper limit value of another numerical range described in stages, and the lower limit value described in one numerical range may be replaced with the lower limit value of another numerical range described in stages. In a numerical range, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples. Each component may contain multiple substances. When multiple substances exist for each component, the content or amount of each component means the total content or amount of the multiple substances, unless otherwise specified.

[0026] <Blower> Fig. 1 is a schematic exploded perspective view showing an example of a blower according to the present embodiment, and Fig. 2 is a schematic cross-sectional view showing the periphery of the blower according to the present embodiment.

[0027] As shown in FIGS. 1 and 2, the blower 100 according to this embodiment includes a blower section 10, a first ventilation member 14, a second ventilation member 16, a guide member 18, and a support member 20.

[0028] The blower 10 is provided, for example, inside the guide member 18, and sucks in and blows air. The blower 10 has, for example, a rotary blade 12 and a drive motor (not shown) that drives the rotary blade 12 to rotate.

[0029] The rotating blades 12 are not particularly limited as long as they are fans that draw in and blow air, and well-known fans such as centrifugal fans, axial fans, mixed flow fans, and cross flow fans can be used depending on the type of blower 100. Specifically, examples of the rotating blades 12 include well-known fans such as propeller fans, sirocco fans, turbo fans, and line flow fans (registered trademark). In this embodiment, a propeller fan is shown as the rotating blades 12.

[0030] An ozone decomposing coating 22 is provided on the surface of the rotary blade 12.

[0031] The first ventilation member 14 is provided, for example, at one end of the guide member 18 on the downstream side in the air blowing direction. Specifically, the first ventilation member 14 is fitted, for example, into an outlet in the guide member 18 that discharges the air blown from the blower 10.

[0032] The first ventilation member 14 is configured, for example, by a honeycomb structure member having through holes as first ventilation holes 14A through which air blown from the blower 10 passes. The honeycomb structure member has a structure in which a plurality of through holes, each with a hexagonal cross section, are closely arranged inside the peripheral frame portion.

[0033] In the first ventilation member 14, an ozone decomposing coating film 22 is provided on the wall surface of the first ventilation hole 14A, that is, on the wall surface of the through-hole of the honeycomb structure.

[0034] The second ventilation member 16 is provided, for example, at one end of the guide member 18 on the upstream side in the air blowing direction. Specifically, the second ventilation member 16 is fitted, for example, into an intake port of the guide member 18 through which air is sucked in by the blower 10.

[0035] The second ventilation member 16 is configured, for example, by a honeycomb structure member having through holes as second ventilation holes 16A through which air drawn into the blower section 10 passes. The honeycomb structure member has a structure in which a plurality of through holes, each with a hexagonal cross section, are arranged without gaps.

[0036] In the second ventilation member 16, an ozone decomposing coating film 22 is provided on the wall surface of the second ventilation hole 16A, that is, on the wall surface of the through-hole of the honeycomb structure.

[0037] The guide member 18 is formed of a cylindrical member having an inner diameter larger than the outer diameter of the rotary blades 12 of the blower 10, and has the blower 10 inside. The guide member 18 guides the air blown from the blower 10 to the first ventilation member 14. The guide member also serves as a guide member that guides the air that has passed through the second ventilation hole 16A of the second ventilation member 16 to the blower 10. An ozone decomposable coating 22 is provided on the inner wall surface of the guide member 18.

[0038] The support member 20 supports, for example, a guide member 18 on which the blower section 10 is provided. The support member 20 is configured, for example, as a tripod. However, the support member 20 is not limited to a tripod and may be configured as a known support member including a base and one or more pillars or plates extending from the base and having one end to movably fix the guide member.

[0039] The ozone decomposing coating 22 includes a manganese oxide catalyst, activated carbon, a polyacrylate dispersant, and a resin. The ozone decomposable coating 22 is provided on at least the wall surface of the first ventilation hole 14A of the first ventilation member 14, the wall surface of the second ventilation hole 16A of the second ventilation member 16, and the blade surface of the rotary blade 12.

[0040] However, from the viewpoint of enabling the blower 100 to efficiently blow air with a reduced ozone concentration, it is preferable that the coating film having high ozone decomposition performance be provided on the parts that come into contact with the sucked air before it is discharged, including the wall surfaces of the ventilation holes of the first ventilation member and the second ventilation member of the blower.

[0041] The ozone decomposable coating film 22 will be described in detail later.

[0042] The blower 100 according to the present embodiment described above is provided with an ozone-decomposing coating film 22 that is provided on the wall surfaces of the first ventilation hole 14A of the first ventilation member 14 and the second ventilation hole 16A of the second ventilation member 16 and that contains a manganese oxide catalyst, activated carbon, a polyacrylate dispersant, and a resin. Due to the above components, the ozone-decomposing coating film 22 has high ozone-decomposing performance.

[0043] In blower 100, air blown from blower section 10 comes into contact with ozone decomposing coating film 22 when passing through first ventilation hole 14A of first ventilation member 14. This decomposes ozone contained in the air. Therefore, blower 100 can blow air with a reduced ozone concentration.

[0044] In blower 100, air drawn into the blowing section comes into contact with ozone decomposing coating film 22 when passing through second ventilation hole 16A of second ventilation member 16. This decomposes ozone contained in the air. As a result, blower 100 can blow air with a reduced ozone concentration.

[0045] In particular, since the blower 100 is provided with both the first ventilation member 14 and the second ventilation member 16 provided with the ozone decomposing coating 22, it is possible to blow air with a further reduced ozone concentration.

[0046] Note that blower 100 may be configured to include at least one of first ventilation member 14 and second ventilation member 16 provided with ozone decomposable coating film 22. Blower 100 may be configured in either of the following ways: (1) a first ventilation member 14 provided with ozone decomposable coating film 22 and a second ventilation member 16 not provided with ozone decomposable coating film 22, or (2) a first ventilation member 14 not provided with ozone decomposable coating film 22 and a second ventilation member 16 provided with ozone decomposable coating film 22. However, from the viewpoint of blowing air with an even lower ozone concentration, it is preferable that the blower 100 is provided with at least the first ventilation member 14 on which the ozone decomposing coating film 22 is provided.

[0047] In the blower 100, the first ventilation member 14 and the second ventilation member 16 are made of honeycomb structure members. Honeycomb structure members have a large wall area for the through-holes through which air passes. In other words, the area to be coated with the ozone decomposable coating film 22 is large, and the area that comes into contact with the ozone decomposable coating film 22 when the air passes through the through-holes is also increased. This makes it possible to blow air with a reduced ozone concentration.

[0048] Here, the first ventilation member 14 may be made of a filter member having mesh holes as first ventilation holes 14A through which the air blown from the blower 10 passes, for example, as shown in FIG. Similarly, the second ventilation member 16 may also be made of a filter member having mesh holes as second ventilation holes 16A through which the air drawn into the blower 10 passes, as shown in FIG.

[0049] The filter member may be any known filter such as a fiber filter (woven fabric filter, nonwoven fabric filter, etc.), a metal filter, a ceramic filter, or a resin filter (including a foamed resin filter). The filter member may be any of a coarse dust filter, a medium-efficiency air filter, a HEPA (High Efficiency Particulate Air Filter) filter, and a ULPA (Ultra Low Penetration Air Filter) filter, depending on the purpose. The filter member may be made up of a plurality of filters with different functions.

[0050] The ozone decomposing coating 22 is also provided on the wall surfaces of the mesh holes of the filter member.

[0051] The filter member has a large wall area of ​​mesh holes through which air passes, meaning that the area coated with the ozone decomposing coating film 22 is large, and the area over which the air passing through the mesh holes comes into contact with the ozone decomposing coating film 22 also increases.

[0052] Therefore, the fan 100 equipped with filter members as the first ventilation member 14 and the second ventilation member 16 can also blow air with an even lower ozone concentration. However, honeycomb structure members have less pressure loss of the air being ventilated than filter members, so the blower 100 equipped with honeycomb structure members as the first ventilation member 14 and the second ventilation member 16 can reduce pressure loss and efficiently blow air with reduced ozone concentration.

[0053] Alternatively, one of the first ventilation member 14 and the second ventilation member 16 may be a honeycomb structure member, and the other a filter member. This embodiment has the advantage of reducing the cost and weight of the blower 100 compared to an embodiment in which both the first ventilation member 14 and the second ventilation member 16 are honeycomb structure members. In this embodiment, it is sufficient that an ozone-decomposing coating film is provided on at least one of the honeycomb structure member and the filter member.

[0054] The first ventilation member 14 and the second ventilation member 16 are not limited to honeycomb structural members or filter members, and may be, for example, (1) a structural member in which a plurality of through holes having a circular or polygonal (triangular, square, etc.) cross-sectional shape are arranged as the first ventilation holes 14A and the second ventilation holes 16A, or (2) a structural member in which a plurality of linear or curved fins are arranged radially or spirally from the center, and the gaps between adjacent fins serve as the first ventilation holes 14A and the second ventilation holes 16A.

[0055] The blower 100 includes a rotating blade 12 provided with an ozone-decomposing coating 22. When air is sucked in and blown by the rotation of the rotating blade 12, the air comes into contact with the ozone-decomposing coating 22. Therefore, the blower 100 can blow air with a reduced ozone concentration.

[0056] The blower 100 is provided with a guide member 18 that guides the air blown from the blower section 10 to the first ventilation member 14. The guide member 18 prevents the blown air from escaping from the periphery of the first ventilation member 14, and can increase the amount of air passing through the first ventilation holes 14A of the first ventilation member 14. Therefore, it is possible to efficiently blow air with a reduced ozone concentration. In addition, the ozone decomposing coating 22 is also provided on the inner wall of the guide member 18. Therefore, the blower 100 can blow air with a further reduced ozone concentration.

[0057] There are no particular limitations on the type of blower 100 as long as it is a device capable of blowing air, and well-known blowers such as electric fans, circulators, air conditioners, air purifiers, radiator fans, ventilation devices, etc. Blower 100 may also be a so-called bladeless fan, which includes a body having a blowing section and an intake port, and a ring member having slits for discharging the air blown from the blowing section. There are no limitations on the installation type of the fan 100, and fans of well-known installation types such as floor-standing type, tabletop type, ceiling-mounted type, sidewall-mounted type, and outdoor installation type may be used. In the blower 100, the first ventilation member 14 may be disposed in the path from the blower 10 until the air is discharged. On the other hand, the second ventilation member 16 may be disposed in the path from the blower 10 until the air is drawn into the blower 10.

[0058] Here, in the blower 100, the ozone decomposable coating film 22 is not limited to being provided on the first ventilation member 14, the second ventilation member 16, the rotary blades 12, and the guide member 18. Ozone decomposable coating film 22 may be provided at least one of a position contacting air blown from blower unit 10 and a position contacting air drawn into blower unit 10. Specifically, for example, ozone decomposable coating film 22 may be provided on at least one of a component constituting the air suction path of blower 100 and a component constituting the air exhaust path of blower 100. This enables blower 100 to blow air with a reduced ozone concentration.

[0059] <Articles with ozone-decomposable coating> The article with an ozone decomposable coating according to this embodiment includes an article body and an ozone decomposable coating provided on the article body, the ozone decomposable coating including a manganese oxide catalyst, activated carbon, a polyacrylate dispersant, and a resin.

[0060] The ozone decomposing coating is provided on at least a part of the surface of the article body that comes into contact with the atmosphere. Details of the ozone decomposing coating will be described later. On the other hand, typical examples of the article body on which the ozone decomposable coating film is applied include honeycomb structure members, filter members, ducts, building materials, and the like.

[0061] The honeycomb structure member may be the honeycomb structure member described in the blower according to the present embodiment, and at least an ozone decomposing coating film is provided on the inner wall surfaces of the through holes of the honeycomb structure member. The filter member may be the same as that described in the blower according to the present embodiment, and at least an ozone-decomposing coating film is provided on the wall surfaces of the mesh holes of the filter member. The honeycomb structure member and filter member with an ozone-decomposable coating film are attached, for example, to the air suction part of a blower (well-known blowers such as electric fans, circulators, air conditioners, air purifiers, radiator fans, and ventilation fans), the air exhaust part of a blower, the outdoor unit of an air conditioner, the air exhaust part of an ozone-based virus removal device, the air exhaust part of a copier, the air exhaust part of a printer, etc.

[0062] Examples of the duct include well-known ducts such as a metal duct, a resin duct, a cylindrical duct, a polygonal cylindrical duct, a flexible duct, etc. Then, for example, at least an ozone-decomposable coating film is provided on the inner wall surface of the duct. Ducts with ozone decomposing coatings are arranged, for example, as air supply ducts, exhaust ducts, air circulation ducts, etc. in air conditioning systems.

[0063] Examples of building materials include well-known materials such as interior and exterior wall materials, roofing materials, floor materials, ceiling materials, screen doors, windows, vinyl sheets for greenhouses, curtains, fences, etc. Then, for example, at least an ozone-decomposable coating film is provided on the exposed surface of the building material.

[0064] In addition to the above, examples of the article body on which the ozone decomposable coating film is applied include parts of a blower, parts of an ozone virus removal device, parts of a copying machine, parts of a printer, and agricultural materials. Examples of parts for virus removal devices, copiers, and printers that use ozone include parts that make up the air exhaust section. Examples of blower parts include the ventilation members, rotating blades (fans), guide members, parts that make up the air suction path of the blower, the air exhaust path of the blower, and parts that make up the outdoor unit of an air conditioner, as described in the blower of the above embodiment. Examples of agricultural materials include sheets or nets for weed control, pest repellent, photosynthesis promotion, wind protection, heat retention, etc.; bags (vegetable bags, fruit bags, etc.); and the like.

[0065] The above-described articles with an ozone decomposing coating according to the present embodiment can be arranged according to the purpose of each article, so that the ozone decomposing coating comes into contact with the atmosphere and decomposes ozone in the atmosphere, thereby realizing an environment with a reduced ozone concentration.

[0066] <Air conditioning system> FIG. 6 is a schematic diagram showing an example of a building having an air conditioning system according to this embodiment. The building 300 has, for example, a ceiling room 304A, a first room 304B, and a second room 304C, which are partitioned by partition walls 302A and 302B.

[0067] The air conditioning system in the building 300 includes, for example, a heat exchange type ventilation device 30 with a fan (not shown) installed in the ceiling room 304A, an air intake duct 32A, an exhaust duct 32B, and an air intake filter member 34. The air supply duct 32A is, for example, an air supply duct for supplying air from the outside of the building 300 to the first room 304B, and is connected to the ventilation device 30. The exhaust duct 32B is a duct for exhausting air from the second room 304C to the outside of the building 300, and is connected to the ventilation device 30. The air supply filter member 34 is a filter that purifies the air supplied from the air supply duct 32A, and is located midway along the path of the air supply duct 32A. The ventilation device 30 supplies air from outside the building 300 to the first room 304B through the air supply duct 32A, and exhausts the air from the second room 304C to the outside of the building 300 through the exhaust duct 32B, thereby air-conditioning each room of the building 300.

[0068] The air conditioning system in the building 300 includes, for example, an air conditioner 36 having a filter member (not shown) installed in the first room 304B, wallpaper 38, and a ceiling material 40. The air conditioning system in the building 300 includes, for example, wallpaper 38 and ceiling material 40 provided in the second room 304C.

[0069] In the air conditioning system according to this embodiment, an ozone-decomposable coating film (not shown) containing a manganese oxide catalyst, activated carbon, a polyacrylate dispersant, and a resin is provided on the surface of the fan of the ventilation device 30, the inner wall surface of the air intake duct 32A, the surface of the air intake filter member 34, the surface of the filter member of the air conditioner 36, the surface of the wallpaper 38, and the surface of the ceiling material 40.

[0070] Therefore, the air supplied by the ventilation device 30 comes into contact with the ozone-decomposing coating provided on the surface of the fan of the ventilation device 30, the inner wall surface of the air supply duct 32A, and the surface of the air supply filter member 34, thereby reducing the ozone concentration. In addition, the air blown by the air conditioner 36 comes into contact with the ozone decomposing coating provided on the surface of the filter member, thereby reducing the ozone concentration. Furthermore, the air present in first room 304B and second room 304C comes into contact with the ozone-decomposing coating provided on the surface of wallpaper 38 and the surface of ceiling material 40, thereby reducing the ozone concentration. Furthermore, if an ozone-based virus removal device or the like is placed in first room 304B, for example, the ozone generated during virus removal can be effectively decomposed.

[0071] In the air conditioning system according to the present embodiment described above, ozone in the air can be decomposed by bringing the air into contact with the ozone decomposing coating film, thereby realizing an environment with a reduced ozone concentration.

[0072] The air conditioning system according to this embodiment is not limited to the above configuration, but may be an air conditioning system that includes one or more selected from the blower according to this embodiment and the article with an ozone-decomposable coating according to this embodiment. Specifically, for example, an air conditioning system provided in a greenhouse, which includes the fan according to the present embodiment and a vinyl sheet with an ozone-decomposable coating film for use in a greenhouse, can be exemplified. Another example is an air conditioning system equipped with an article according to the above embodiment (for example, a component (such as a filter member) that constitutes the air exhaust section of the virus removal device, or a wall material of the removal device) that has medical instruments such as surgical scalpels in a removal device room that is equipped with a virus removal device that removes viruses using ozone. Another example is an air conditioning system equipped with the items according to the present embodiment (for example, the blower according to the present embodiment, the wall material of the storage room) in a storage room that stores medical instruments sterilized in a sterilization room.

[0073] <Ozone decomposition method> The ozone decomposition method according to this embodiment is a method in which atmospheric air is brought into contact with an ozone-decomposing coating film containing a manganese oxide catalyst, activated carbon, a polyacrylate dispersant, and a resin, thereby decomposing ozone in the air. Specifically, in the ozone decomposition method according to the present embodiment, for example, one selected from the blower according to the present embodiment and the article with an ozone decomposable coating according to the present embodiment is used to bring the ozone decomposable coating into contact with the atmosphere, thereby decomposing ozone in the atmosphere. More specifically, for example, the air conditioning system according to the present embodiment is used to bring the ozone decomposable coating into contact with the atmosphere, thereby decomposing ozone in the atmosphere. Therefore, the ozone decomposition method according to the present embodiment can realize an environment with a reduced ozone concentration.

[0074] <Coating film> The ozone decomposable coating film 22 (hereinafter also referred to as "coating film") will be described below, with the reference numerals omitted.

[0075] The coating film contains a manganese oxide catalyst, activated carbon, a polyacrylate dispersant, and a resin. Specifically, from the viewpoint of reducing VOC emissions and contributing to environmental measures, the coating film is preferably made of a cured coating film of an aqueous coating composition (hereinafter simply referred to as "coating composition") that contains a water-based solvent and a pH adjuster in addition to the manganese oxide catalyst, activated carbon, a polyacrylate dispersant, and a resin.

[0076] The ozone-decomposing coating film has high ozone-decomposing performance due to the inclusion of the above-mentioned components. The reasons for this are as follows:

[0077] The manganese oxide catalyst and activated carbon contained in the coating film are both components that have ozone decomposition properties. When a manganese oxide catalyst and activated carbon are used together as ozone-decomposing components, a higher ozone decomposing performance can be obtained compared to when either one is used alone. The reason for this is not entirely clear, but it is thought that the ozone decomposing performance is improved compared to when either the manganese oxide catalyst or activated carbon is used alone for the following reasons (1) to (4): (1) The heat of reaction between activated carbon and ozone accelerates the ozone catalytic reaction of manganese oxide catalysts. (2) By using a manganese oxide catalyst in combination with activated carbon, ozone decomposition performance can be achieved over a wide temperature range. (3) The manganese oxide catalyst penetrates into the pores of the activated carbon, allowing the activated carbon and the manganese oxide catalyst to come into efficient contact with ozone. (4) The manganese oxide catalyst prevents the oxidation and consumption of activated carbon due to active oxygen and the like.

[0078] On the other hand, to improve the ozone decomposition ability of the coating film, it is necessary that the manganese oxide catalyst and activated carbon be blended with good dispersibility. To achieve this, the manganese oxide catalyst and activated carbon must be highly dispersible in the coating composition for forming the coating film, and the coating composition must be able to maintain this dispersibility over a long period of time, i.e., storage stable. When activated carbon is used alone as the component with ozone decomposition ability, the activated carbon adsorbs and aggregates the resin component (organic matter) of the paint due to its adsorption properties, and therefore it is difficult to ensure the stability of the paint with the specified amount of activated carbon blended to obtain the desired ozone decomposition performance.

[0079] However, by using activated carbon and a manganese oxide catalyst in combination, the amount of activated carbon can be reduced, making it possible to satisfy both the ozone decomposition performance of the coating film and the storage stability of the coating composition. Furthermore, the life of the ozone decomposition performance can be extended compared to when activated carbon is used alone. Furthermore, manganese oxide catalysts are expensive, and using only manganese oxide catalysts would result in high costs. However, activated carbon is inexpensive, and so using a manganese oxide catalyst and activated carbon in combination reduces costs.

[0080] Here, the manganese oxide catalyst and activated carbon having ozone decomposition ability are in the form of particulate powder. To make the powdered manganese oxide catalyst and activated carbon into a paint, the manganese oxide catalyst and activated carbon need to be uniformly dispersed in the components of the paint composition, such as the resin and solvent. However, manganese oxide catalysts and activated carbon, which have large surface areas capable of absorbing a large amount of ozone, tend to aggregate. In particular, activated carbon has pores to which the resin (organic matter) and manganese oxide catalyst, which are components of the coating composition, adhere. This makes them prone to aggregation. If the dispersibility of the manganese oxide catalyst and activated carbon is low and there is a lot of aggregation, aggregation gelation and an increase in viscosity occur, making it difficult to produce a paint. Furthermore, clogging of the piping, pumps, etc. of the painting equipment occurs during painting. Even if a paint can be produced, the paint film will have bumps and roughness, and if it is applied to cover the substrate, the paint film will be thick, lacking in film-forming and adhesion properties, and resulting in a paint film with poor appearance. If the dispersibility of the manganese oxide catalyst and activated carbon is low and there is a lot of aggregation, the amount of ozone that can be adsorbed is small, and the coating film cannot achieve high ozone decomposition performance. Naturally, if the dispersibility of the manganese oxide catalyst and activated carbon is low and there is a lot of aggregation, the coating composition will lack storage stability due to aggregation gelation and increased viscosity, making it difficult to store for a long period of time. Therefore, when powdered manganese oxide catalyst and activated carbon are made into a paint, it is preferable to highly disperse the manganese oxide catalyst and activated carbon to prevent them from agglomerating.

[0081] In contrast, when a polyacrylate dispersant is blended with a manganese oxide catalyst and activated carbon, aggregation of the manganese oxide catalyst and activated carbon can be prevented (deflocculation) even in a coating composition containing a resin, and the manganese oxide catalyst and activated carbon can be finely and highly dispersed in the coating composition, and the dispersion stability can also be improved. The polyacrylate-based dispersant is thought to provide high dispersion and dispersion stability to the manganese oxide catalyst and activated carbon due to, for example, (1) adsorption of the polyacrylate-based dispersant to the manganese oxide catalyst and activated carbon due to electrical repulsion, and (2) steric hindrance caused by the polyacrylate anchor groups, polymer chains, etc. In other words, it is thought that the adsorption and steric hindrance caused by the polyacrylate-based dispersant prevent aggregation (deagglomeration) of the manganese oxide catalyst and activated carbon, stabilizing the manganese oxide catalyst and activated carbon at a fine particle size. In particular, polyacrylate-based dispersants are high molecular weight substances with multiple adsorption sites. Therefore, even when used in low concentrations, polyacrylate-based dispersants adsorb to manganese oxide-based catalysts and activated carbon, enabling high dispersion of the manganese oxide-based catalysts and activated carbon, eliminating the need for high concentrations. As a result, polyacrylate-based dispersants are less likely to inhibit ozone adsorption onto the manganese oxide-based catalysts and activated carbon.

[0082] Therefore, the polyacrylate dispersant can sufficiently deaggregate and stabilize the manganese oxide catalyst and activated carbon in the coating composition, i.e., the manganese oxide catalyst and activated carbon can be finely and highly dispersed. For example, the dispersity of the manganese oxide catalyst and activated carbon in the coating composition, as measured by a grind gauge (specifically, a grind gauge conforming to JISK 5600 and JISK 5400 (1990)), can be reduced to a maximum particle size (Dmax) of 20 μm or less by the linear method. In addition, the 90% cumulative particle size (D90) on a volume basis, measured by laser analysis (specifically, laser analysis using a laser diffraction particle size distribution analyzer), of the manganese oxide catalyst and activated carbon in the coating composition can be made 10 μm or less. Furthermore, a coating film formed from a coating composition in which the manganese oxide catalyst and activated carbon are highly dispersed in such fine particles exhibits high ozone decomposition performance due to the well-dispersed manganese oxide catalyst and activated carbon blended and the high ozone adsorption capacity of the manganese oxide catalyst and activated carbon. Furthermore, the coating film is free of bumps and roughness, ensuring excellent film-forming properties and adhesion to substrates. Furthermore, the coating film has good smoothness and good coating appearance. Furthermore, in coating compositions using polyacrylate-based dispersants, the dispersion stability of the manganese oxide-based catalyst and activated carbon is high and they do not re-aggregate, so the coating compositions have high storage stability and can be stored for long periods of time.

[0083] From the above, a coating film containing the above components has high ozone decomposition performance.

[0084] The coating film will be described in detail below.

[0085] (Manganese oxide catalyst / activated carbon) Manganese oxide catalysts (1) adsorb ozone, (2) reduce the activation energy of the ozone self-decomposition reaction, and (3) decompose and desorb ozone to convert it into oxygen, thereby purifying and detoxifying ozone.

[0086] On the other hand, activated carbon converts ozone into carbon monoxide, carbon dioxide (carbon dioxide), active oxygen, oxygen, etc. through (1) the adsorption of ozone into its pores, and (2) a reaction between the ozone adsorbed on the activated carbon and the activated carbon, or the ozone receiving electrons from the activated carbon (i.e., a decrease in the activation energy of the ozone self-decomposition reaction). This allows the ozone to be purified and rendered harmless. In particular, manganese oxide catalysts are most active in the high temperature range (for example, around 80°C), whereas activated carbon is highly active over a wide temperature range including room temperature (15 to 25°C) and in high humidity environments.

[0087] In this way, the coating film containing the manganese oxide catalyst and activated carbon can decompose and purify ozone.

[0088] -Manganese oxide catalyst- Manganese oxide (Mn x O y Examples of the manganese monoxide (MnO)-based catalyst include manganese dioxide (manganese (IV) oxide)-based catalysts, and spinel-type manganate metal-based catalysts. Among these, manganese oxide catalysts are particularly preferred, as they have high catalytic activity and improve the ozone decomposition ability of the coating film. In general, manganese oxides known as manganese dioxide are non-stoichiometric compounds, and therefore, in reality, MnO x The composition is approximately (x=1.93~2). Here, the manganese dioxide may be any of natural manganese dioxide, manganese dioxide produced by electrolysis or chemical synthesis, amorphous manganese dioxide, and manganese dioxide having a crystalline structure. Examples of the crystalline structure of manganese dioxide include alpha, beta, gamma, and delta types, with α-manganese dioxide (cryptomelane-form manganese dioxide) being more preferred. Manganese dioxide may also have an amorphous structure.

[0089] The manganese oxide catalyst may be a catalyst based on manganese oxide (for example, MnO2) and containing a promoter such as NiO, CuO, or AgO. The manganese oxide catalyst may be a catalyst containing calcium oxide or the like that adsorbs moisture. However, the manganese oxide catalyst preferably has a manganese oxide content of 70% or more, more preferably 80% or more.

[0090] The specific surface area of ​​the manganese oxide catalyst measured by the BET method using N2 adsorption is 100m 2 / g~400m 2 / g is preferred. Specific surface area is 400m 2 / g or less, catalyst aggregation is suppressed, and the dispersibility and dispersion stability of the catalyst in the coating composition are improved. Improved catalyst dispersibility and dispersion stability result in the catalyst being well dispersed in the coating film, enhancing the ozone decomposition performance of the coating film. Furthermore, improved catalyst dispersibility reduces clogging of the coating equipment for the coating composition and the occurrence of paint particles (aggregates) on the surface of the coating film, improving the film-forming and adhesion properties of the coating film. Furthermore, chipping and peeling of the coating film, as well as catalyst shedding, are suppressed. Improved catalyst dispersion stability also increases the storage stability of the coating composition. On the other hand, if the specific surface area is 100m 2 When the ozone decomposition capacity is 1 / g or more, the ozone decomposition capacity of the coating film is further improved.

[0091] Therefore, the specific surface area measured by the BET method of N2 adsorption is 100m 2 / g~400m 2 When a manganese oxide catalyst having a manganese oxide content in the range of 0.1 wt. / g is used, the coating film has good film-forming and adhesion properties, the catalyst is less likely to fall off, and high ozone decomposition performance can be obtained more effectively and sustainably. In addition, the coating composition has good storage stability. The specific surface area of ​​the manganese oxide catalyst is preferably 150 m 2 / g~350m 2 / g, and more preferably 180m 2 / g~300m 2 / g.

[0092] The median diameter (average particle diameter) of the manganese oxide catalyst is preferably 1 μm to 20 μm. When the median diameter is 20 μm or less, the specific surface area of ​​the catalyst is large, and the ozone decomposition performance of the coating film is enhanced. In addition, the film-forming and adhesion properties of the coating film are improved, making it less likely for the coating film to peel off and the catalyst to fall off. On the other hand, a median diameter of 1 μm or more improves the dispersibility and dispersion stability of the catalyst in the coating composition. When the dispersibility and dispersion stability of the catalyst are improved, the catalyst is blended with good dispersion in the coating film, improving the ozone decomposition performance of the coating film. Furthermore, improved catalyst dispersibility reduces clogging of the coating composition coating equipment and the occurrence of paint particles (aggregates) on the surface of the coating film, improving the film-forming and adhesion properties of the coating film. Furthermore, chipping and peeling of the coating film and catalyst shedding are suppressed. Furthermore, improved catalyst dispersion stability increases the storage stability of the coating composition.

[0093] Therefore, when a manganese oxide catalyst with a median diameter (average particle diameter) in the range of 1 μm to 20 μm is used, the coating film has good film-forming and adhesion properties, the catalyst is less likely to fall off, and high ozone decomposition performance can be obtained more effectively and sustainably, and good storage stability of the coating composition can be obtained. The median diameter (average particle diameter) of the manganese oxide catalyst is more preferably 3 μm to 18 μm, and even more preferably 5 μm to 15 μm.

[0094] Thus, the median diameter (average particle diameter) is in the range of 1 μm to 20 μm, and the specific surface area by the BET method is 100 to 400 m 2 When a manganese oxide catalyst having a solubility in the range of 1 / g is used, the catalyst is incorporated into the coating film with particularly good dispersibility, and high ozone decomposition performance can be obtained.

[0095] -Activated carbon- Examples of activated carbon include activated carbon made from sawdust, wood chips, charcoal, bamboo charcoal, coal (lignite, brown coal, bituminous coal), petroleum-based materials (petroleum pitch, oil carbon, etc.), walnut shell charcoal, coconut shell charcoal, resin (phenolic resin, epoxy resin, etc.), rayon, etc. The activated carbon may be, for example, activated carbon supporting an organometallic complex having cobalt, iron, or the like as a central metal. Among these, preferred activated carbons include coconut shell activated carbon, petroleum pitch-based activated carbon, and wood-based activated carbon, which have a very high ozone adsorption specific surface area. Coconut shell activated carbon, which has a carbon content of 90% or more and is made from coconut, oil palm, sago palm, or other palms that contain a large amount of carbon, is preferred.

[0096] The specific surface area of ​​activated carbon measured by the BET method of N2 adsorption is 500m 2 / g~3000m 2 / g is preferred. Specific surface area is 3000m 2 / g or less, aggregation of the activated carbon is suppressed, and the dispersibility and dispersion stability of the activated carbon in the coating composition are improved. When the dispersibility and dispersion stability of the activated carbon are improved, the activated carbon is blended into the coating film with good dispersibility, and the ozone decomposition performance of the coating film is enhanced. Furthermore, when the dispersibility of the activated carbon is improved, clogging of the coating equipment of the coating composition and the formation of paint particles (aggregates) on the surface of the coating film are less likely to occur, improving the film-forming and adhesion properties of the coating film. Furthermore, chipping and peeling of the coating film and shedding of the activated carbon are suppressed. Furthermore, when the dispersion stability of the activated carbon is improved, the storage stability of the coating composition is increased. On the other hand, the specific surface area is 500m 2 When the ozone decomposition capacity is 1 / g or more, the ozone decomposition capacity of the coating film is further improved.

[0097] Therefore, the specific surface area measured by the BET method of N2 adsorption is 500m 2 / g~3000m 2 / g, the coating composition exhibits good film-forming and adhesion properties, is less susceptible to catalyst detachment, and exhibits more effective and sustained high ozone decomposition performance. Furthermore, the coating composition exhibits good storage stability. The specific surface area of ​​activated carbon is preferably 600m 2 / g~2500m 2 / g or less, and more preferably 900m 2 / g~2000m 2 / g or less.

[0098] The total pore volume of activated carbon is calculated from the nitrogen adsorption amount when the relative pressure P / P0 is 1.0 in the nitrogen BET nitrogen adsorption isotherm, and is 0.1 cm 3 / g~1.5cm 3 / g, and 0.2 cm 3 / g~1.0cm 3 / g is more preferred. The average pore diameter of the activated carbon (calculated by dividing the total pore volume by the BET specific surface area by 4) is preferably 0.3 to 10 nm, more preferably 0.5 to 5 nm, from the viewpoint of ozone adsorption ability and preventing clogging due to particulate matter in the atmosphere.

[0099] The median diameter (average particle diameter) of the activated carbon is preferably 1 μm to 20 μm. When the median diameter is 20 μm or less, the specific surface area of ​​the activated carbon is large, and the ozone decomposition performance of the coating film is enhanced. In addition, the film-forming and adhesion properties of the coating film are improved, making it difficult for the coating film to peel off and the activated carbon to fall off. On the other hand, a median diameter of 1 μm or more improves the dispersibility and dispersion stability of the activated carbon in the coating composition. When the dispersibility and dispersion stability of the catalyst are improved, the activated carbon is blended with good dispersibility in the coating film, enhancing the ozone decomposition performance of the coating film. Furthermore, improved dispersibility of the activated carbon reduces clogging of the coating equipment for the coating composition and the occurrence of paint particles (aggregates) on the surface of the coating film, improving the film-forming and adhesion properties of the coating film. Furthermore, chipping and peeling of the coating film, as well as shedding of the activated carbon, are suppressed. Furthermore, improved dispersion stability of the activated carbon improves the storage stability of the coating composition.

[0100] Therefore, when activated carbon with a median diameter (average particle diameter) in the range of 1 μm to 20 μm is used, the coating film has good film-forming and adhesion properties, the activated carbon is less likely to fall off, and high ozone decomposition performance can be obtained more effectively and sustainably, and good storage stability of the coating composition can be obtained. The median diameter (average particle diameter) of the activated carbon is more preferably 3 μm to 18 μm, and even more preferably 5 μm to 15 μm.

[0101] Thus, the median diameter (average particle diameter) is in the range of 1 μm to 20 μm, and the specific surface area by the BET method is 500 to 3000 m 2 By using activated carbon having a % ozone concentration in the range of 0.1 to 1.0 g / g, the activated carbon can be blended into the coating film with particularly good dispersibility, and the coating film can have high ozone decomposition performance.

[0102] -Method for measuring the specific surface area of ​​manganese oxide catalysts and activated carbon- "Specific surface area" is the specific surface area measured by the BET method of N2 adsorption. The BET (Brunauer-Emmett-Teller) method is a method in which molecules with known adsorption areas are adsorbed onto particle surfaces at liquid nitrogen temperatures, and the specific surface area of ​​a sample is determined from the amount of adsorption. This method determines the specific surface area by low-temperature physical adsorption of nitrogen.

[0103] -Method for measuring the median diameter (average particle diameter) of manganese oxide catalysts and activated carbon- According to the definition of terms in the text and commentary of JIS Z 8901 "Test Powders and Test Particles," the "median diameter" is the particle size (diameter) when the number (or mass) of particles larger than a certain particle size in the particle size distribution of a powder accounts for 50% of that of the total powder, i.e., the particle size that is 50% oversized, and is usually called the median diameter or 50% particle diameter and expressed as D50. By definition, the size of a particle group is expressed by the average particle size and median size, but in this specification, the "median size" refers to the value indicated in the product description or measured by laser diffraction / scattering. This "median size measured by laser diffraction / scattering" refers to the particle size (D50) at which the cumulative weight is 50% in the particle size distribution obtained by laser diffraction / scattering using a laser diffraction particle size analyzer. The above figures are not strict and there are differences between products, and including errors due to measurement, etc., it is not possible to deny the possibility of an error of less than 10%. From the perspective of this error, a normal distribution is shown, and since particle size also shows a normal distribution, even if the median diameter is considered to be approximately equal to the average particle size, the difference between the two is within a few percent, and can be considered an error.

[0104] -Manganese oxide catalyst and activated carbon content- The blending ratio of the manganese oxide catalyst to the activated carbon is preferably 20 / 80≦activated carbon / manganese oxide catalyst≦80 / 20, more preferably 30 / 70≦activated carbon / manganese oxide catalyst≦70 / 30, by mass ratio. When the blending ratio of the manganese oxide catalyst and activated carbon is within the above range, a synergistic effect of ozone decomposition properties can be obtained, particularly by combining the manganese oxide catalyst and activated carbon, and high ozone decomposition performance can be obtained.

[0105] The total amount of the manganese oxide catalyst and activated carbon is preferably 60% by mass to 90% by mass, more preferably 65% ​​by mass to 85% by mass, and even more preferably 70% by mass to 80% by mass, based on the coating film. When the total amount of the manganese oxide catalyst and activated carbon is within the above range, high ozone decomposition performance can be obtained without impairing the adhesion of the coating film.

[0106] (Polyacrylate-based dispersant) The polyacrylate-based dispersant is a dispersant that enables high dispersion of the manganese oxide-based catalyst and activated carbon. The polyacrylate-based dispersant is, for example, a dispersant based on a polyacrylate salt, an acrylic skeleton, or a modified acrylic skeleton, and includes modified polyacrylate-based dispersants.

[0107] The weight average molecular weight of the polyacrylate dispersant is preferably 5,000 to 30,000. The higher the molecular weight of a polyacrylate-based dispersant, the more adsorption sites there are within the molecule, so even at low dispersant concentrations, the manganese oxide-based catalyst and activated carbon can be adsorbed at multiple points, preventing aggregation. When the weight-average molecular weight of the polyacrylate dispersant is 5000 or more, the polyacrylate dispersant has a sufficient number of adsorption sites in the molecule, which increases the number of adsorption points and improves the dispersibility of the manganese oxide catalyst and activated carbon, thereby further improving the ozone decomposition performance of the coating film. On the other hand, if the weight-average molecular weight of the polyacrylate dispersant is 30,000 or less, the compatibility and affinity between the dispersant and the paint components of the coating composition can be prevented from decreasing, and the dispersibility of the manganese oxide catalyst and activated carbon can be prevented from decreasing, thereby preventing a decrease in the ozone decomposition performance of the coating film.

[0108] Therefore, when a polyacrylate-based dispersant with a weight-average molecular weight in the range of 5,000 to 30,000 is used, it is compatible with other materials and can further improve the dispersibility of the manganese oxide-based catalyst and activated carbon. The weight average molecular weight of the polyacrylate dispersant is more preferably 6,000 to 28,000, and even more preferably 7,000 to 25,000.

[0109] The weight average molecular weight (Mw) is measured by gel permeation chromatography (GPC) and is a value obtained by converting a chromatogram measured by GPC into the molecular weight of standard polystyrene.

[0110] The acid value of the polyacrylate-based dispersant is preferably 1 to 50. This is because it can suppress deterioration in the adsorption properties of the dispersant, which can occur due to the polarity of other materials, such as additives such as pigments. Therefore, by using a dispersant with an acid value within the range of 1 to 50, the dispersion stability of the catalyst and activated carbon can be ensured regardless of the type of additive. The acid value of the polyacrylate dispersant is more preferably 3-48, and even more preferably 5-45. The acid value of the polyacrylate dispersant is a value measured using the neutralization titration method in accordance with JIS K0070.

[0111] The hydrogen ion exponent of the polyacrylate dispersant is preferably pH 4 to pH 9. This is because it can suppress deterioration in the dispersibility of additives, such as pigments, which can occur depending on the type of additive. Therefore, by using a dispersant with a hydrogen ion exponent within the pH range of 4 to pH 9, the dispersion stability of the additive can be ensured regardless of the type of additive. The hydrogen ion exponent of the polyacrylate dispersant is more preferably pH 4.5 to pH 8.5, and even more preferably pH 5 to pH 8. The hydrogen ion exponent of a polyacrylate dispersant is a value measured at a liquid temperature of 25°C on a diluted resin solution (emulsion, dispersion, aqueous solution) with a resin concentration of approximately 1% to 99%.

[0112] Thus, by using a polyacrylate-based dispersant with a weight-average molecular weight in the range of 5,000 to 30,000, an acid value in the range of 1 to 50, and a hydrogen ion exponent in the range of pH 4 to 9, it is possible to obtain high ozone decomposition performance without impairing the adhesion of the coating film, and the dispersibility of the components of the coating composition is also improved.

[0113] Commercially available polyacrylate dispersants include, for example, DESPERBYK from BYK-Chemie, EFKA from Ciba Specialty Chemicals and EFKA ADDITIVES BV, DISPARLON from Kusumoto Chemicals Co., Ltd., and SN Thickener from SANNOPKO.

[0114] The content of the polyacrylate dispersant is preferably 1.5 to 75 parts by mass, more preferably 2 to 60 parts by mass, and even more preferably 2.5 to 50 parts by mass, relative to 100 parts by mass of the total amount of the manganese oxide catalyst and activated carbon. When the content of the polyacrylate-based dispersant is within the above range, high ozone decomposition properties of the coating film can be imparted, and high ozone decomposition properties of the coating film and high storage stability of the coating composition can be achieved at the same time.

[0115] (resin) The resin is a resin that binds the manganese oxide catalyst and activated carbon in the coating film. The resin is preferably an aqueous resin. The aqueous resin may be either a water-soluble resin that can be dissolved in water or a water-dispersible resin that can be dispersed in water. Examples of resins include epoxy resins, epoxy ester resins, polyester resins, (meth)acrylic resins (including methacrylic resins), acrylic silicone resins, polyester resins, polyurethane resins, alkyd resins, urethane resins, vinyl resins, urea resins, styrene-butadiene latex (SBR), acrylonitrile-butadiene rubber (NBR), etc. Resins may be used singly or in combination of two or more.

[0116] Here, the resin may be added to the coating composition in any of the following forms: a water-soluble resin (aqueous resin solution), an emulsion resin, or a dispersion resin. The term "emulsion" is also called an emulsion, and its original meaning is a system in which liquid particles are in the form of colloidal particles or larger particles in a liquid (a dispersed system) (Nagakura Saburo et al., "Iwanami Dictionary of Physics and Chemistry (5th Edition)," p. 152, published February 20, 1998 by Iwanami Shoten Co., Ltd.). However, in this specification, the term "emulsion" is used in the broader sense of the term, meaning "a system in which solid or liquid particles are dispersed in a liquid."

[0117] As the resin, (meth)acrylic resin or polypropylene resin is preferred, particularly in terms of compatibility and dispersibility with the manganese oxide catalyst and activated carbon, weather resistance of the coating film, cost, adhesion of the coating film, and dispersion stability of each component. (Meth)acrylic resin has excellent adhesion to metals, and polypropylene resin has excellent adhesion to both metals and resins. Therefore, a coating film containing a (meth)acrylic resin has high adhesion to metal members (ventilation members, rotating blades, guide members, etc.), while a coating film containing a polypropylene resin has high adhesion to metal or resin members (ventilation members, rotating blades, guide members, etc.).

[0118] (Meth)acrylic resins broadly include acrylic resins and methacrylic resins. The acrylic resin means a homopolymer or copolymer of a (meth)acrylic monomer selected from (meth)acrylic acid (meaning acrylic acid or methacrylic acid; the same applies hereinafter) and a (meth)acrylic acid ester (meaning an acrylic acid ester or a methacrylic acid ester; the same applies hereinafter), or a copolymer of a (meth)acrylic monomer and a monomer copolymerizable with the (meth)acrylic monomer.

[0119] Examples of (meth)acrylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 2,2-bis(hydroxymethyl)ethyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, glycidyl (meth)acrylate, aminoethyl (meth)acrylate, aminopropyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, methoxyethyl (meth)acrylate, methoxypropyl (meth)acrylate, methoxybutyl (meth)acrylate, and stearyl (meth)acrylate.

[0120] Monomers copolymerizable with (meth)acrylic monomers are preferably monomers having an ethylenically unsaturated group, such as ethylene, propylene, butylene, butadiene, styrene, α-methylstyrene, vinylphenol, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl pivalate, vinyl benzoate, vinyl alcohol, allyl alcohol, crotonic acid, itaconic acid, maleic acid, fumaric acid, (meth)acrylamide, N-methylolacrylamide, N-butoxymethylol(meth)acrylamide, and (meth)acrylonitrile. While emulsion polymerization is a common copolymerization method, it is not limited thereto. In addition, in the case of acids, their alkali metal salts, alkaline earth metal salts, and the like may also be used.

[0121] The (meth)acrylic resin may be modified with a urethane resin, an epoxy resin, a phenol resin, a melamine resin, or the like, such as a urethane-modified (meth)acrylic resin, an epoxy-modified (meth)acrylic resin, a phenol-modified (meth)acrylic resin, or a melamine-modified (meth)acrylic resin.

[0122] The (meth)acrylic resin is preferably a weakly alkaline (meth)acrylic resin having a hydrogen ion exponent within the range of pH 7 to pH 9. Weakly alkaline (meth)acrylic resins have high dispersibility in water, which is the solvent for the coating composition, and therefore form dense coating films with good film-forming properties and uniformity, and also have high adhesion to metal substrates. The hydrogen ion exponent of the (meth)acrylic resin is a value measured at a liquid temperature of 25°C for a diluted resin solution (emulsion, dispersion, aqueous solution) with a resin concentration of approximately 1% to 99%.

[0123] The (meth)acrylic resin added to the coating composition preferably has a median particle size (average particle size) in the range of 50 nm to 150 nm. If the particle size is within this range, the resin content will have high dispersibility in water, and the coating film will have good film-forming properties and uniformity, and will exhibit good adhesion to metal substrates. The median diameter (average particle diameter) of the (meth)acrylic resin is more preferably 60 nm to 140 nm, and even more preferably 70 nm to 130 nm.

[0124] Polypropylene resins include homopolymers made from propylene alone, random polymers copolymerized with small amounts of ethylene, and block copolymers in which rubber components (EPR) are dispersed in homo-random polymers. Polypropylene resins also include modified polypropylene resins and chlorinated polypropylene resins.

[0125] The polypropylene resin is preferably a weakly alkaline polypropylene resin with a hydrogen ion exponent in the range of pH 7 to pH 9. Weakly alkaline polypropylene resins have high dispersibility in water, which is the solvent for the coating composition, and therefore form dense coating films with good film-forming properties and uniformity, and also have high adhesion to metal substrates. The hydrogen ion exponent of polypropylene resin is a value measured at a liquid temperature of 25°C for a diluted resin solution (emulsion, dispersion, aqueous solution) with a resin concentration of approximately 1% to 99%.

[0126] The weakly alkaline polypropylene resin to be added to the coating composition preferably has a median particle size (average particle size) in the range of 50 nm to 150 nm.Within this range, the resin content has high dispersibility in water, and the coating film has good film-forming properties and uniformity, and the coating film can exhibit good adhesion to metal substrates. The median diameter (average particle diameter) of the weakly alkaline polypropylene resin is more preferably 60 nm to 140 nm, and even more preferably 70 nm to 130 nm.

[0127] The resin content is preferably within a range of 5 to 100 parts by mass, and more preferably within a range of 10 to 50 parts by mass, relative to 100 parts by mass of the total amount of the manganese oxide catalyst and activated carbon (solid content). When the resin content is 5% by mass or more, good adhesion to the substrate is easily obtained, and peeling and chipping of the coating film, as well as falling off of the manganese oxide catalyst and activated carbon, can be further suppressed. On the other hand, if the resin content is 100 parts by mass or less, the decrease in the ozone decomposing ability of the coating film can be further suppressed. Therefore, the content of the resin is preferable because it makes it easier to achieve both adhesion and ozone decomposition properties of the coating film.

[0128] (pH adjuster) The pH adjuster neutralizes the paint composition, thereby suppressing the sedimentation of the manganese oxide catalyst and activated carbon due to a decrease in viscosity of the paint composition, thereby making it easier to maintain high dispersibility of the manganese oxide catalyst and activated carbon in the paint composition. The pH adjuster is a compound that adjusts the hydrogen ion exponent of the coating composition for forming a coating film to within a range of pH 7 to pH 12, more preferably pH 8 to pH 11.5, and even more preferably pH 9.5 to pH 11. The pH adjuster is a compound that conceptually includes neutralizing agents. Examples of pH adjusters include low-boiling amines such as triethylamine (TEA); ammonia; dimethylaminoethanol; and the like.

[0129] (Other ingredients) The coating film may contain various additives other than the above components. For example, the coating film may contain pigments such as coloring pigments, anti-rust pigments, extender pigments, and functional pigments in order to improve rust prevention and chipping resistance, etc. Furthermore, the coating film may contain additives in order to improve the coatability and coating film performance of the coating composition used to form the coating film.

[0130] Examples of color pigments include carbon black, titanium oxide, iron oxide, zinc oxide, organic azo chelate pigments, insoluble azo pigments, condensed azo pigments, diketopyrrolopyrrole pigments, benzimidazolone pigments, phthalocyanine pigments, indigo pigments, perinone pigments, perylene pigments, dioxane pigments, quinacridone pigments, isoindolinone pigments, metal complex pigments, yellow lead, yellow iron oxide, red iron oxide, and titanium dioxide.

[0131] Examples of anti-rust pigments include zinc phosphate, zinc phosphite, aluminum polyphosphate, aluminum tripolyphosphate, zinc calcium molybdate, zinc orthophosphate, zinc polyphosphate, zinc molybdate, zinc phosphomolybdate, aluminum phosphomolybdate, zinc oxide, zinc phosphosilicate, aluminum zinc phosphate, calcium zinc phosphate, zinc calcium cyanamide, barium metaborate, and magnesium aminophosphate. From the viewpoint of environmental protection, the anti-rust pigment is preferably an anti-rust pigment that does not contain harmful heavy metals, such as a chromium-based anti-rust pigment. The content of the anti-rust pigment is preferably 30% by mass or less, more preferably 20% by mass or less, based on the paint film. If the content of the anti-rust pigment is within the above range, the stability of the paint composition is also good.

[0132] Examples of extender pigments include talc, calcium carbonate, barium sulfate, calcium sulfate, mica, clay, silica, diatomaceous earth, alumina, baryta, and silicon dioxide. Talc is particularly preferred as the extender pigment. Talc forms many layers stacked together within the coating film, and the denseness of the layers formed by the arrangement of the talc can prevent corrosive factors from penetrating the coating film.

[0133] Other additives include, for example, viscosity modifiers, film-forming aids, dispersants that mainly disperse pigments, antifoaming agents, fillers, plasticizers, anti-sagging agents, film-forming aids, thixotropic agents, leveling agents, pH adjusters, neutralizing agents, ultraviolet absorbers, ultraviolet stabilizers, anti-settling agents, adhesion promoters, curing catalysts, neutralizing agents, driers (desiccant), stabilizers, and surface conditioners (coating surface conditioners).

[0134] For example, examples of dispersants that mainly disperse pigments better include polycarboxylic acid dispersants. Examples of antifoaming agents include silicone-based antifoaming agents and acrylic-based antifoaming agents. These antifoaming agents prevent the coating composition from becoming uneven due to the generation of fine bubbles during mixing to prepare the coating composition, and can adjust the viscosity and flowability. Furthermore, antifoaming suppresses the formation of bubbles in the coating film. This prevents the generation of rust due to moisture penetrating through the bubbles, thereby improving the rust prevention properties of the coating film. Examples of the dryer (desiccant) include metal dryers (metal driers) such as cobalt naphthenate, lead naphthenate, etc. The dryer promotes drying at the stage when the coating composition is applied to form a coating film, and can promote further polymerization of the aqueous resin to form a dense coating film. Examples of stabilizers include alkanolamine derivatives (diisopropanolamine, ethanolamine, diethanolamine, triisopropanolamine, triethanolamine, etc.), which can stabilize the coating composition by adjusting the fluidity, viscosity, dispersibility, etc. The alkanolamine derivatives may also function as initial rust inhibitors.

[0135] (Method of manufacturing a coating composition for forming a coating film) An example of a method for producing a coating composition will be described below, but the method is not limited to this. In a method for producing a coating composition, for example, first, a dispersion step is carried out in which a solvent containing water as a main component, a manganese oxide catalyst, activated carbon, and a polyacrylate dispersant are mixed, and the mixture is stirred using a disperser to disperse the catalyst and activated carbon. Here, a solvent containing water as a main component is a solvent containing water in an amount of 50 mass % or more, 75 mass % or more, 90 mass % or more, 95 mass % or more, or 100 mass % based on the total solvent.

[0136] Examples of dispersing machines used in the dispersion step include ball mills, bead mills, high-pressure injectors, dissolvers, Banbury mixers, planetary mixers, butterfly mixers, spiral mixers, roll mills, sand mills, paint shakers, grain mills, high-speed impeller mills, open kneaders, vacuum kneaders, attritors, high-speed dispersers, homomixers, homogenizers, colloid mills, microfluidizers, sonolators, and cavitrons. The dispersing machine is preferably a bead mill or a roll mill, which can disperse the manganese oxide catalyst and activated carbon to a predetermined fine size with a small amount of energy.

[0137] Next, a neutralization step is carried out in which the mixture that has been subjected to the dispersion step is mixed with a pH adjuster (neutralizer). In the neutralization step, it is preferable to adjust the hydrogen ion exponent of the coating composition with a pH adjuster to within the range of pH 7 to pH 12, more preferably pH 8 to pH 11.5, and even more preferably pH 9.5 to pH 11. This is because it prevents settling of the coating components due to a decrease in the viscosity of the coating composition, enables uniform dispersion and stabilization of the coating composition, and makes it easier to ensure uniform coating film performance after application.

[0138] Next, the mixture that has undergone the neutralization step is mixed with a resin and stirred with a stirrer to form a paint. In the paint forming step, various additives are mixed with the mixture that has undergone the neutralization step together with the resin, as needed.

[0139] Through the above steps, the desired coating composition is obtained.

[0140] (Method of forming coating film) The method for forming the coating film is not particularly limited, and a method in which the coating composition is applied to the object to be coated and then cured can be used. As the coating method, a known coating method can be used. Examples of known coating methods include air spraying, shower coating, spraying, roll coating, curtain flow coating, die coating, brush coating, dipping, shibori (squeezing) method, knife coating, bar coating, and electrostatic coating. Using a known coating method, a coating is applied to a predetermined portion of the object to be coated in any desired amount, thickness, and form.

[0141] The applied coating composition film is cured by natural drying, heat drying, or forced drying in a dryer to remove the solvent, thereby forming the desired coating film.

[0142] (Test example) Here, the coating film having ozone decomposing properties and the aqueous coating composition for forming the coating film will be explained in more detail with reference to test examples.

[0143] -Test Examples 1 to 3, Comparative Examples 1 to 6- First, Table 1 shows the formulation of test examples of aqueous coating compositions for forming coating films.

[0144] [Table 1]

[0145] As shown in Table 1, the aqueous coating composition of Test Example 1 was prepared using activated carbon (raw material: coconut shell, average particle size: 5 μm, BET specific surface area: 2000 m 2 / g) and a manganese dioxide catalyst (manganese dioxide content: 70% or more, average particle size: 5 μm, BET specific surface area: 250 m 2 / g), a polyacrylate dispersant, water as a solvent, triethylamine (TEA) as a pH adjuster (neutralizer), an aqueous dispersion containing polypropylene resin as a resin, and additives (viscosity adjuster, thickening aid). The aqueous coating compositions of Test Examples 2 and 3 are examples in which an aqueous dispersion containing an acrylic resin was used as the resin instead of the polypropylene resin of Test Example 1. The other materials were the same as those of Test Example 1. In Table 1, the amount of activated carbon is calculated as a solid content, and the amount of water used in the dispersion process includes the amount of water that was pre-contained as a solvent in the activated carbon material product, in addition to the ion-exchanged water added as a solvent.

[0146] In producing the aqueous coating compositions of Test Examples 1 to 3, first, activated carbon, a manganese dioxide catalyst, water as a solvent, and a polyacrylate dispersant were mixed according to the formulation in Table 1, and the mixture was placed in a bead mill to carry out a dispersion process. The bead mill used 1.5 mm zircon (zirconia bead mill) as media, and the mixed materials were dispersed at a rotation speed of 1500 rpm for 90 minutes. As a result, in Test Examples 1 to 3, the particle size of the particles (activated carbon and manganese dioxide catalyst) in the mixture after dispersion was measured by the linear method using a grind gauge in accordance with JIS K 5600 and JIS K 5400 (1990), and the maximum particle size (Dmax) was 20 μm or less. In addition, when measured by laser analysis using a laser diffraction particle size distribution analyzer, the cumulative particle size (D90) of 90% of the volume was 10 μm or less.

[0147] Next, a neutralization step was carried out in which the mixture obtained was neutralized by adding triethylamine (TEA) as a pH adjuster according to the formulation in Table 1. Next, the neutralized mixture was mixed with polypropylene resin (solid content 30% by mass) or acrylic resin (solid content 40% by mass) as the resin according to the formulation in Table 1, and then additives (viscosity modifier, thickening aid) were added. The mixture was then stirred in a disperser for 5 to 10 minutes to mix and disperse the various materials, thereby carrying out the paint-making process.

[0148] Through the above steps, the aqueous coating compositions of Test Examples 1 to 3 were obtained.

[0149] On the other hand, for comparison, aqueous coating compositions according to Comparative Examples 1 to 6 were prepared according to the formulations shown in Table 1 using a dispersant different from that used in the test examples or no dispersant. Comparative Example 1 is an example in which no dispersant was used. Comparative Example 2 is an example in which a polycarboxylic acid ammonium salt (anion) was used as the dispersant instead of the polyacrylate-based dispersant used in the test example. Comparative Examples 3 and 6 are examples in which a polycarboxylate sodium salt (anion) was used as the dispersant instead of the polyacrylate-based dispersant used in the test examples. Comparative Example 4 is an example in which a phosphate ester was used as the dispersant instead of the polyacrylate-based dispersant used in the test examples. Comparative Example 5 is an example in which polyurethane was used as the dispersant instead of the polyacrylate-based dispersant used in the test examples. The aqueous coating compositions according to these comparative examples were also prepared using the same procedures as in the above test examples.

[0150] Here, the various aqueous coating compositions of the test examples and comparative examples prepared according to the formulations in Table 1 were subjected to evaluation tests for their storage stability and ozone decomposition properties.

[0151] For storage stability, the prepared aqueous coating compositions were stored at 20°C for one month, and the presence or absence of aggregation after one month was checked. If no aggregation occurred after one month of storage at 20°C, the result was rated A, and if sedimentation and separation occurred due to aggregation, the result was rated C.

[0152] The ozone decomposition test was carried out using an ozone decomposition test apparatus 200 shown in Figure 4. Specifically, a test specimen T for evaluation, which was a polypropylene TP substrate 220 (hereinafter referred to as PP material 220) coated with a coating composition and then dried, was placed flat inside a pipe 210 of the ozone decomposition test apparatus 200 shown in Figure 4. The test specimen T was a test specimen in which the coating composition was applied to a coating area of ​​5 cm x 7 cm on the surface of the PP substrate 220 having an area of ​​5 cm x 7 cm, and then dried at 100°C for 10 minutes, forming a cured coating film 220A on the PP material 220. The coating composition is applied to the PP material 220 until the base material is completely covered.

[0153] Then, air containing ozone (initial ozone concentration: 4.0 ppm (volume basis), temperature: 25°C) was supplied at a wind speed of 1.0 m / s into the pipe 210 containing the test piece T, and the ozone concentration before passing through the PP material 220 with the cured coating film 220A, i.e., the test piece T, was measured by an ozone sensor 231. In addition, the ozone concentration near the test piece T was measured by an ozone sensor 232. The distance x between the ozone sensor 232 and the cured coating film 220A was 2 mm. The evaluation test was carried out at room temperature (normal temperature) of about 25°C. The ozone decomposition rate (= {(b1-b2) / b1} x 100) (%) by the cured coating film 1 was calculated from the ozone concentration b1 measured by the ozone sensor 231 and the ozone concentration b2 measured by the ozone sensor 232. An ozone decomposition removal rate of 24% or more was rated A, an ozone decomposition removal rate of 18% or more but less than 24% was rated B, and an ozone decomposition removal rate of less than 18% was rated C.

[0154] As an overall evaluation, if both the storage stability and ozone decomposition evaluation tests were A, it was marked as A, and otherwise it was marked as C. The results of these evaluation tests are shown in the lower part of Table 1.

[0155] As shown in the lower part of Table 1, in the aqueous coating compositions of Test Examples 1 to 3, which used a polyacrylate-based dispersant as the dispersant, the manganese dioxide-based catalyst and activated carbon were highly dispersed, and the dispersion stability was also high, so that no aggregation occurred even when stored at 20°C for one month, and the storage stability was high. Furthermore, the cured coating films formed using the aqueous coating compositions of Test Examples 1 to 3 had little bumps or roughness. Furthermore, the cured coating films had excellent film-forming properties, being able to sufficiently cover the substrate with a dry film thickness of approximately 5 μm, and also had excellent ozone decomposition performance.

[0156] In contrast to this, in Comparative Example 1, in which no dispersant was used, the activated carbon and manganese dioxide catalyst were not dispersed and aggregated into a gel, making it impossible to form a paint. In Comparative Example 2, in which an ammonium polycarboxylate salt was used as the dispersant, the activated carbon and manganese dioxide catalyst were not dispersed and aggregated into a gel, making it impossible to prepare a paint.

[0157] On the other hand, in Comparative Examples 3 to 5, which used polycarboxylate sodium salt (anionic), phosphate ester, and polyurethane as dispersants, paints could be produced, but the dispersibility and dispersion stability of the activated carbon and manganese dioxide catalyst were low, resulting in aggregation after storage at 20°C for one month, resulting in storage stability problems. Furthermore, the dispersibility of the manganese dioxide catalyst and activated carbon was low, and the particles did not become as fine as in the test examples using polyacrylate dispersants. As a result, the paint film after application was prone to lumps and roughness. Furthermore, the paint film, which was applied to sufficiently cover the substrate, was thick and had poor film-forming properties. Furthermore, the ozone decomposition performance was also poor compared to the test examples using polyacrylate dispersants.

[0158] In Comparative Example 6, increasing the amount of polycarboxylic acid sodium salt (anion) as a dispersant improved storage stability, but reduced ozone decomposition. This is thought to be because the large amount of dispersant inhibited ozone from adsorbing onto the activated carbon and manganese dioxide catalyst. That is, in Comparative Example 6, a small amount of dispersant did not ensure storage stability, while increasing the amount of dispersant inhibited ozone adsorption onto the activated carbon and manganese dioxide catalyst, making it impossible to obtain the desired ozone decomposition performance compared to the test examples.

[0159] As described above, the dispersants used in the comparative examples were unable to achieve both good storage stability and ozone decomposition properties.

[0160] In contrast, in Test Examples 1 to 3, which used a polyacrylate-based dispersant, the activated carbon and manganese dioxide-based catalyst could be finely dispersed with a small amount of dispersant. Furthermore, Test Examples 1 to 3 showed little re-aggregation and excellent dispersibility and dispersion stability, resulting in good storage stability, and the cured coating film had few bumps and roughness, good film-forming properties and appearance, and demonstrated excellent ozone decomposition performance.

[0161] That is, in this test example, even with a small amount of polyacrylate-based dispersant used, the activated carbon and manganese dioxide-based catalyst can be finely dispersed, thereby increasing the amount of ozone that can be adsorbed by the activated carbon and manganese dioxide-based catalyst. As a result, the ozone decomposition performance of the activated carbon and manganese dioxide-based catalyst can be fully utilized, resulting in excellent ozone decomposition performance. In addition, the dispersion stability was high and the storage stability was excellent. Therefore, stable storage for a long period of time was possible, and long-term storage stability was excellent.

[0162] Furthermore, as mentioned above, in Comparative Examples 3 to 5, the dispersibility of the activated carbon and manganese dioxide catalyst was low and there was a lot of aggregation, which resulted in the formed cured coating film being full of bumps and roughness, poor film-forming properties of the coating film and poor adhesion to the substrate, and poor coating appearance. In contrast, in this test example, the use of a polyacrylate-based dispersant allowed the activated carbon and manganese dioxide-based catalyst to be finely dispersed, resulting in a cured coating film with fewer bumps and roughness, and good film-forming properties and appearance. Furthermore, in Test Examples 1 to 3, which used polypropylene resin and acrylic resin as the resin, even when the adhesion test described below was conducted on a metal substrate, the number of squares that peeled off was two or less, and high adhesion and bonding properties were achieved on the metal substrate. In particular, in Test Examples 2 and 3, which used polypropylene resin as the resin, the number of squares that peeled off was two or less in the adhesion test described below, not only for metal substrates but also for resin substrates, and high adhesion and bonding properties were obtained even for resin substrates. Therefore, when polypropylene resin is used as the resin, high adhesion of the coating film to metal and resin substrates can be ensured, and since no special processing equipment is required for coating film adhesion, costs can be reduced. On the other hand, when an acrylic resin is used as the resin, the adhesiveness and adhesion to a metal substrate are good, but in order to ensure high adhesion of the coating film to a resin substrate, it is preferable to apply a pretreatment to the substrate before painting.

[0163] -Test Examples 2-1 to 2-8- The present inventors have conducted detailed studies on the optimum blend amount of polyacrylate-based dispersant, as shown in Table 2. That is, among the formulations of Test Example 2 shown in Table 1, only the amount (g) of polyacrylate-based dispersant was varied, and all the ingredients other than the polyacrylate-based dispersant were kept the same as in Test Example 2, and various aqueous paint compositions with different concentrations of polyacrylate-based dispersant were prepared. Here too, the same materials and procedures as those in Table 1 above were used and fabricated in the same manner. The aqueous coating compositions containing different concentrations of polyacrylate dispersant were also subjected to the same storage stability and ozone decomposition test evaluations as in Table 1 above.

[0164] [Table 2]

[0165] As shown in Table 2, Test Example 2-1 is an example in which the aqueous coating composition contains a polyacrylate dispersant at a concentration of 0.1 mass %, and the blending amount of the polyacrylate dispersant is 0.9 parts by mass per 100 parts by mass of the total amount of manganese dioxide catalyst and activated carbon (solid content). In this example, the dispersion stability of the activated carbon and manganese dioxide catalyst was inferior to Test Examples 2-2 to 2-7, and aggregation occurred after storage at 20°C for one month. On the other hand, in Test Example 2-8, the polyacrylate dispersant was contained in the aqueous coating composition at a concentration of 9.1 mass%, and the blending amount of the polyacrylate dispersant was 86.2 mass parts per 100 mass parts of the total amount of the manganese dioxide catalyst and activated carbon (solid content). In this example, the ozone decomposition rate was lower than in Test Examples 2-2 to 2-7. This is thought to be because the amount of dispersant was so large that it inhibited ozone from adsorbing onto the activated carbon and manganese dioxide catalyst.

[0166] In contrast, Test Examples 2-2 to 2-7 are examples in which the polyacrylate dispersant was contained in the aqueous coating composition at a concentration of 0.3 to 4.8 mass %, and the amount of polyacrylate dispersant blended was within the range of 2.6 to 43.1 mass parts per 100 mass parts of the total amount of manganese dioxide catalyst and activated carbon (solid content). In these examples, it was confirmed that the appropriate blending amount of polyacrylate dispersant particularly resulted in high dispersion of the manganese dioxide catalyst and activated carbon, good dispersion stability, and no inhibition of ozone adsorption, achieving both high storage stability and ozone decomposition ability.

[0167] The inventors have also confirmed that storage stability can be ensured particularly when the amount of polyacrylate dispersant blended is preferably 1.5 parts by mass or more, more preferably 2 parts by mass or more, and even more preferably 2.5 parts by mass or more, per 100 parts by mass of the total amount of manganese dioxide catalyst and activated carbon (solids). Furthermore, the inventors have confirmed that particularly high ozone decomposition ability can be obtained, and the film-forming properties, adhesion, and appearance of the coating film are also good when the amount of polyacrylate dispersant blended is preferably 75 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less.

[0168] Therefore, the polyacrylate dispersant is preferably blended in an amount within the range of 1.5 to 75 parts by mass per 100 parts by mass of the total amount of the manganese dioxide catalyst and activated carbon (solid content). Within this range, high storage stability and ozone decomposition ability can be effectively achieved, and the coating film's film-forming properties, adhesion, and appearance are also good. The blend amount of the polyacrylate dispersant is more preferably 2 to 60 parts by mass, and even more preferably 2.5 to 50 parts by mass, per 100 parts by mass of the total amount of the manganese dioxide catalyst and activated carbon (solid content).

[0169] In the aqueous coating composition, the concentration of the polyacrylate dispersant is preferably within the range of 0.3 to 5% by mass. Within this range, high storage stability and ozone decomposability can be effectively achieved, and the coating film has good film-forming properties, adhesion, and appearance. In the aqueous coating composition, the concentration of the polyacrylate dispersant is more preferably 0.3 to 2% by mass.

[0170] -Test Examples 4 to 8, Comparative Examples 7 to 8- The present inventors have conducted detailed studies on the optimum blend of manganese dioxide catalyst and activated carbon, as shown in Tables 3 and 4 below. First, we investigated the effect of the blending ratio (ratio) of activated carbon with ozone-decomposing ability and manganese dioxide catalyst on the performance of the aqueous coating composition and the coating film formed therefrom. Specifically, as shown in Table 3 below, various coating compositions were prepared by changing the blending ratio (ratio) of activated carbon and manganese dioxide. Here, the same materials and procedures as in Table 1 above were used and the coating compositions were prepared. In addition, the prepared coating compositions were tested for storage stability and ozone decomposition.

[0171] Here, the storage stability of the aqueous coating compositions was evaluated by checking for the presence or absence of aggregation after storage for one month at a temperature of 20°C, the same temperature conditions as in Table 1. If a small amount of settling due to aggregation was observed after storage at 20°C for one month, but stirring before application caused no problems with paintability, this was designated B.

[0172] Meanwhile, the ozone decomposition test was carried out as follows. Specifically, as shown in Fig. 5, a test specimen T, which was prepared by applying an aqueous coating composition to a polypropylene TP substrate 220 (PP material 220) for evaluation and drying it, was placed in a 20 L Mylar bag 250. Test specimen T was prepared by applying the coating composition to a coating area of ​​5 cm x 7 cm on the surface of the PP substrate 220 having an area of ​​5 cm x 7 cm, and then drying it at 100°C for 10 minutes, thereby forming a cured coating film 220A on the PP material 220. Next, air was sealed into the Mylar bag 250 using an air blower, and then ozone generated by an ozone generator was injected to adjust the ozone concentration in the bag 50 to 0.2 ppm (volume basis), and the Mylar bag 250 was then heat-sealed. After 30 minutes had passed, the ozone concentration in the Mylar bag 250 was measured using the ozone sensor 233, and the ozone decomposition rate was calculated by comparing it with the initial ozone concentration. The evaluation test was carried out at room temperature (normal temperature) of 25° C. Each of the coating compositions was applied to the PP material 220 until the base material was completely covered.

[0173] Furthermore, for comparison, Comparative Examples 7 and 8 were prepared in which only either activated carbon or manganese dioxide catalyst was blended. These examples were also similarly subjected to evaluation tests for storage stability and ozone decomposition performance. The formulations of the various coating compositions prepared are shown in the upper part of Table 3, and the results of the evaluation tests are shown in the lower part of Table 3. Note that, also in Table 3, the amount of activated carbon is calculated as a solid content, and the amount of water used in the dispersion process includes not only the ion-exchanged water added as a solvent, but also the amount of water that was pre-contained as a solvent in the activated carbon material product.

[0174] [Table 3]

[0175] As shown in Table 3, in Comparative Example 7, in which activated carbon was not blended and only a manganese dioxide catalyst was blended, the ozone decomposition rate was 75.9%, which was a lower ozone decomposition rate than the test examples. In addition, in Comparative Example 8, which did not contain a manganese dioxide catalyst and contained only activated carbon, the ozone decomposition rate was 50%, which was significantly inferior to the test examples.Furthermore, the storage stability was also extremely low. This is because activated carbon, due to its adsorption properties, aggregates by adsorbing a large amount of resin (organic matter), which is a component of the coating. It is clear that the incorporation of activated carbon alone cannot ensure paint stability, i.e., storage stability.

[0176] In contrast, in the test examples in which a manganese dioxide catalyst and activated carbon were used in combination, the ozone decomposition rate was significantly improved, and extremely high ozone decomposition performance was demonstrated, compared to Comparative Examples 7 and 8 in which only a manganese dioxide catalyst or only activated carbon was used alone.

[0177] Here, of the manganese dioxide catalyst and activated carbon required to ensure a predetermined high ozone decomposition performance, if the amount of activated carbon is too large, it may become difficult to ensure the stability (storage stability) of the paint.Furthermore, since the activated carbon is oxidized and consumed over long-term use, it may become difficult to ensure high durability. On the other hand, even if the blending ratio of activated carbon is small, the effect of the ozone purification properties of activated carbon is not utilized, and the effect of improving ozone decomposition ability by combining activated carbon and a manganese dioxide-based catalyst is small, making it difficult to obtain high ozone decomposition performance. In particular, manganese dioxide catalysts are highly resistant to moisture, chlorides, and atmospheric SO x and MO x Therefore, in order to ensure high ozone decomposition ability for a long period of time, it is preferable to blend a predetermined amount of activated carbon with the activated carbon.

[0178] According to the inventors' intensive experimental research, as shown in Table 3 for Test Examples 4 to 8, by preferably setting the ratio of activated carbon (solid content) to manganese dioxide catalyst in the aqueous coating composition to 20 / 80≦activated carbon / manganese dioxide catalyst≦80 / 20, a good ozone decomposition rate can be obtained and practical storage stability can be more easily ensured. In particular, as shown in Test Examples 5 to 7, by setting the ratio of activated carbon (solid content) to manganese dioxide catalyst to, more preferably, 30 / 70≦activated carbon / manganese dioxide catalyst≦70 / 30, excellent ozone decomposition rate and storage stability can be obtained, making it easier to ensure extremely high ozone decomposition property and paint stability over a long period of time. The ratio (mass ratio) of activated carbon (solid content) to manganese dioxide catalyst in the aqueous coating composition corresponds to the ratio of activated carbon to manganese dioxide catalyst in the coating film components formed from that aqueous coating composition. That is, if the ratio of activated carbon (solid content) to manganese dioxide catalyst in the aqueous coating composition is 20 / 80≦activated carbon / manganese dioxide catalyst≦80 / 20, the cured coating film obtained from the aqueous coating composition will also contain activated carbon to manganese dioxide catalyst in a ratio of 20 / 80≦activated carbon / manganese dioxide catalyst≦80 / 20.

[0179] -Test Examples 7-1 to 7-5- Furthermore, the present inventors conducted the following test to investigate the effect of the amounts of activated carbon and manganese dioxide catalyst with ozone decomposition ability on coating film performance. In the formulation of Test Example 7 shown in Table 3, the weight ratio of activated carbon (solid content) to manganese dioxide catalyst in the aqueous coating composition (coating film components) was kept constant at 70 / 30, activated carbon / manganese dioxide catalyst, but tests were conducted in which the amounts of activated carbon and manganese dioxide catalyst were increased or decreased. Specifically, as shown in Table 4, various coating compositions were prepared with blends of activated carbon and manganese dioxide catalyst such that the concentrations of activated carbon and manganese dioxide catalyst in the coating film formed from the aqueous coating composition were 33% to 83% by mass. The blending composition and materials other than the activated carbon and manganese dioxide catalyst were all the same as in Test Example 7, and the preparation was carried out using the same procedure as above. That is, the blending amounts (g) of all the blending materials other than the activated carbon and manganese dioxide catalyst were the same as in Test Example 7, and only the blending amounts (g) of the activated carbon and manganese dioxide catalyst were changed, and the preparation was carried out using the same procedure as above. The prepared coating compositions were then tested for ozone decomposition and adhesion to substrates.

[0180] Here, the ozone decomposition test was carried out using the ozone decomposition test apparatus shown in FIG. 4, as in Test Example 1 above. For the adhesion test, a test specimen was used in which the aqueous coating composition was air-sprayed onto a PP substrate and dried at 100°C for 10 minutes to form a cured coating film on the PP substrate. The test specimens were then evaluated for adhesion (cross-cut method) in accordance with JIS-K5600-5-6:1999. Specifically, 11 parallel cuts were made in the cured coating film of the test specimens, spaced 1 mm apart, using a utility knife to create a total of 100 1 mm x 1 mm squares. Next, adhesive tape (masking tape) was firmly pressed onto these 100 squares and then peeled off in one go, and the number of squares that peeled off was measured. If two or fewer squares peeled off, the test specimen was given an A rating, and if three or more squares peeled off, the test specimen was given a B rating. The concentrations of activated carbon and manganese dioxide catalyst in the various coating compositions prepared are shown in the upper part of Table 4, and the results of the evaluation tests are shown in the lower part of Table 4.

[0181] [Table 4]

[0182] As shown in Table 4, it was found that the ozone decomposition performance improved as the concentration of activated carbon and manganese dioxide catalyst increased. In particular, as shown in Test Examples 7-3 to 7-5, high ozone decomposition properties were obtained when the concentration of activated carbon and manganese dioxide catalyst in the coating film formed from the aqueous coating composition was 63% or more. As shown in Test Examples 7-4 to 7-5, when the catalyst concentration in the coating film components was 73% or higher, it is presumed that even if the catalyst concentration was increased, the increase in ozone decomposition ability was small because there was a limit to the dispersibility with a given amount of dispersant. On the other hand, as shown in Test Example 7-5, when the concentrations of activated carbon and manganese dioxide catalyst became too high, the adhesion performance decreased. If the adhesion performance to the substrate is low, the coating film peeling and the coating components are likely to fall off, and there is a risk that a sustained high ozone decomposition performance cannot be obtained.

[0183] Here, according to the inventors' experimental research, when the ratio of activated carbon (solid content) to manganese dioxide catalyst in the aqueous coating composition (i.e., in the coating film) is 20 / 80≦activated carbon / manganese dioxide catalyst≦80 / 20, it has been confirmed that particularly high ozone decomposition performance can be obtained when the total amount of activated carbon (solid content) and manganese dioxide catalyst in the coating film components is preferably 60 mass% or more, more preferably 70 mass% or more. Furthermore, it has been confirmed that adhesion performance of the coating film to the substrate is particularly good when the total amount of activated carbon (solid content) and manganese dioxide catalyst in the coating film is particularly preferably 90 mass% or less, more preferably 85 mass% or less.

[0184] Therefore, the total amount of activated carbon (solid content) and manganese dioxide catalyst in the coating film is preferably 60% by mass to 90% by mass, and more preferably 70% by mass to 80% by mass, which particularly ensures adhesion to the substrate and maintains high ozone decomposition performance for a long period of time. The total amount (mass%) of activated carbon and manganese dioxide in the coating film formed from the aqueous coating composition was calculated by dividing the total solid content of activated carbon and manganese dioxide by the total solid content ratio of the aqueous coating composition that constitutes the coating film × 100.

[0185] As explained above, the above test examples demonstrate that the polyacrylate-based dispersant allows for fine and highly dispersed manganese dioxide catalysts and activated carbon, resulting in less lumps in the cured coating film and a coating film with excellent film-forming and adhesion properties. Furthermore, the highly dispersed manganese dioxide catalyst and activated carbon are able to adhere a large amount of ozone, thereby demonstrating high ozone decomposition performance. In particular, the use of a manganese dioxide-based catalyst, which has high catalytic activity for ozone decomposition among manganese oxide catalysts, provides high ozone decomposition performance. Furthermore, the combined use of a manganese dioxide-based catalyst and activated carbon provides higher ozone decomposition performance than when either catalyst is used alone. Furthermore, because activated carbon is inexpensive, costs can be reduced. Additionally, the polyacrylate-based dispersant enhances the dispersion stability of the manganese dioxide catalyst and activated carbon, resulting in practically good coating stability and storage stability.

[0186] Manganese dioxide catalysts have a median particle size (average particle size) in the range of 1 to 20 μm and a BET specific surface area of ​​100 to 400 m 2 It is preferable to use a manganese dioxide catalyst having a manganese dioxide content in the range of 0.1g / g. A manganese dioxide catalyst having such properties provides a coating film with particularly high dispersibility and dispersion stability of the coating composition and high ozone decomposition properties. The activated carbon has a median diameter (average particle diameter) in the range of 1 to 20 μm and a BET specific surface area of ​​500 to 3000 m 2 / g, it is preferable to use activated carbon having such properties. Activated carbon having such properties can provide a coating film that is particularly excellent in dispersibility and dispersion stability of the coating composition and has high ozone decomposition properties.

[0187] The polyacrylate dispersant preferably has a weight-average molecular weight in the range of 500 to 30,000, an acid value in the range of 1 to 50, and a pH in the range of 5 to 9. A polyacrylate dispersant with these properties can achieve high dispersion and dispersion stability of paint components with a small amount of dispersant, particularly without impairing ozone decomposition performance. The content of the polyacrylate dispersant is preferably within the range of 1.5 to 70 parts by mass per 100 parts by mass of the total amount of the manganese dioxide catalyst and activated carbon. This allows for particularly high ozone decomposition and storage stability to be achieved. Furthermore, by including the polyacrylate dispersant in the aqueous coating composition within the range of 0.3 to 5% by mass, particularly high ozone decomposition and storage stability can be achieved.

[0188] The resin is preferably a (meth)acrylic resin or a polypropylene resin. These resins are compatible with manganese dioxide catalysts and activated carbon, and the manganese dioxide catalysts and activated carbon are easily dispersed uniformly in the resin. In particular, (meth)acrylic resins have a wide range of molecular weights to choose from, making it easy to design the desired coating film performance characteristics and forming coating films with high weather resistance, water resistance, and chemical resistance. Furthermore, polypropylene resins have excellent adhesion to resin substrates as well as metal substrates, and can exhibit excellent coating film performance, such as ozone decomposition performance, for a long period of time.

[0189] The manganese dioxide catalyst and activated carbon (solid content) are preferably blended in a mass ratio of 20 / 80≦activated carbon / manganese dioxide catalyst≦80 / 20, which in particular ensures paint stability while providing a synergistic effect in ozone decomposition properties due to the combination of the manganese dioxide catalyst and activated carbon. The manganese oxide catalyst and activated carbon are preferably blended in such a way that the total amount of the manganese oxide catalyst and activated carbon in the coating film is within the range of 60% by mass to 90% by mass, which allows for high ozone decomposition performance to be obtained without impairing the adhesion of the coating film to the substrate.

[0190] As explained above, it is clear that an ozone-decomposing coating film containing a manganese oxide catalyst, activated carbon, a polyacrylate dispersant, and a resin has high ozone-decomposing performance. Therefore, it can be seen that a blower having this ozone decomposing coating can blow air with a reduced ozone concentration. [Explanation of symbols]

[0191] 10. Blower 12 Rotating blades 14 First ventilation member 14A First Vent 16 Second ventilation member 16A Second Vent 18 Guide member 20 Support member 22 Paint film 100 Blower

Claims

1. The coating film comprises a solvent containing water as a main component, a manganese oxide catalyst, activated carbon, a polyacrylate dispersant that enables dispersion of the manganese oxide catalyst and the activated carbon, a resin that binds the manganese oxide catalyst and the activated carbon in the coating film, and a pH adjuster; the manganese oxide catalyst is a manganese dioxide catalyst, the blending ratio of the manganese oxide catalyst to the activated carbon is 30 / 70≦activated carbon / manganese oxide catalyst≦50 / 50 by mass; the content of the polyacrylate-based dispersant is within a range of 2.6 parts by mass to 43.1 parts by mass relative to 100 parts by mass of the total amount of the manganese oxide-based catalyst and the activated carbon; The activated carbon, ２ The specific surface area measured by the BET method of adsorption is 500 m ２ / g to 3000m ２ / g, The polyacrylate-based dispersant is a dispersant based on a salt of polyacrylate, excluding salts of polycarboxylic acids, or an acrylic skeleton or modified acrylic skeleton, and is a dispersant having a weight-average molecular weight in the range of 5,000 to 30,000, an acid value in the range of 1 to 50, and a hydrogen ion exponent in the range of pH 4 to pH 9.

2. 2. The aqueous coating composition according to claim 1, wherein the total amount of the manganese oxide catalyst and the activated carbon is 60% by mass to 90% by mass relative to the cured film of the aqueous coating composition.

3. 3. The aqueous coating composition according to claim 1, wherein the resin is at least one selected from the group consisting of a (meth)acrylic resin and a polypropylene resin.

4. The degree of dispersion of the manganese oxide catalyst and the activated carbon measured by a grind gauge is ｍａｘ 4. The aqueous coating composition according to claim 1, wherein the particle size is 20 μm or less.

5. The manganese oxide catalyst and the activated carbon have a 90% cumulative particle diameter (D ９０ 5. The aqueous coating composition according to claim 1, wherein the particle size is 10 μm or less.

6. 6. The aqueous coating composition according to claim 1, wherein the activated carbon is a powdered activated carbon.

7. a dispersion step of mixing and dispersing a solvent containing water as a main component, a manganese oxide catalyst, activated carbon, and a polyacrylate dispersant that enables dispersion of the manganese oxide catalyst and the activated carbon; a neutralization step of mixing a pH adjuster with the dispersed mixture; a paint production step of mixing the neutralized mixture with the manganese oxide catalyst and a resin that binds the activated carbon in a paint film; and the manganese oxide catalyst is a manganese dioxide catalyst, the blending ratio of the manganese oxide catalyst to the activated carbon is 30 / 70≦activated carbon / manganese oxide catalyst≦50 / 50 by mass; the content of the polyacrylate-based dispersant is within a range of 2.6 parts by mass to 43.1 parts by mass relative to 100 parts by mass of the total amount of the manganese oxide-based catalyst and the activated carbon; The activated carbon, ２ The specific surface area measured by the BET method of adsorption is 500 m ２ / g to 3000m ２ / g, The polyacrylate-based dispersant is a polyacrylate salt, excluding salts of polycarboxylic acids, or a dispersant based on an acrylic skeleton or a modified acrylic skeleton, and has a weight-average molecular weight in the range of 5,000 to 30,000, an acid value in the range of 1 to 50, and a hydrogen ion exponent in the range of pH 4 to pH 9.

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