Deodorizing article and process for producing the same

Abstract

To provide a deodorizing material which exhibits the effect of an acid hydrazide having an effect of removing aldehydes together with activated carbon having an effect of removing aldehydes although it has an effect of many odor gas components, and to provide a method for producing the deodorizing material.SOLUTION: The deodorant comprises a support 10, and a first deodorant layer 21 and a second deodorant layer 22 sequentially fixed to the support 10, wherein the first deodorant layer 21 contains activated carbon and a binder, and the second deodorant layer 22 contains a functional material composed of at least one of silica gel and zeolite, acid hydrazide, and a binder.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a deodorizing material and a method for producing the same. [Background technology]

[0002] In recent years, due to changes in living environments and growing health consciousness, air conditioning equipment such as air conditioners, air purifiers, humidifiers, and dehumidifiers are widely used in various living spaces such as homes, offices, factories, and automobiles. These air conditioning equipment use various air filters to obtain purified air.

[0003] Air filters are required to remove malodorous gases present in living spaces such as homes, offices, factories, automobiles, etc. Components of malodorous gases include lower aldehydes such as formaldehyde and acetaldehyde, ammonia, amines such as trimethylamine, lower fatty acids such as acetic acid and isovaleric acid, mercaptans such as methyl mercaptan, SO2, NO2, and aromatic hydrocarbons such as toluene and xylene. In particular, acetaldehyde falls under both the 22 types of specific odorous substances designated in the Offensive Odor Prevention Act and the 13 types of volatile organic compounds (VOCs) for which the Ministry of Health, Labour and Welfare has set concentration guideline values.

[0004] Activated carbon, which is generally used as a deodorizing agent, is effective against many odorous gas components, but has difficulty in adsorbing aldehydes (Patent Document 1). It is known that acid hydrazides are effective in removing aldehydes (Patent Document 2). However, acid hydrazides are almost ineffective against odorous gases other than aldehydes.

[0005] Therefore, it is considered to use activated carbon in combination with acid hydrazide, but it is known that when used in combination, activated carbon acts as a catalyst to oxidize the functional group (amine group) of the acid hydrazide, resulting in a decrease in performance against aldehydes (Non-Patent Document 1). The deodorizing material is obtained by applying a slurry containing a deodorizing agent to a support and drying the applied slurry. Activated carbon as a deodorizing agent must be dried so that the water inside the activated carbon is sufficiently removed. However, if the activated carbon is dried at a high temperature in consideration of production efficiency, the performance of the coexisting acid hydrazide will be significantly reduced. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-58075 [Patent Document 2] International Publication No. 2009 / 122975 [Non-patent literature]

[0007] [Non-Patent Document 1] Journal of Chemical Engineering, 2006, Vol. 32, No. 1, pp. 72-78 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a deodorizing material that utilizes the effects of both activated carbon, which is effective against many odorous gas components but does not have the effect of removing aldehydes, and acid hydrazide, which has the effect of removing aldehydes, and a method for producing the same. [Means for solving the problem]

[0009] The present invention employs the following configuration. [1] A device comprising a support, a first deodorizing agent layer, and a second deodorizing agent layer sequentially fixed to the support, the first deodorizing agent layer contains activated carbon and a binder, The second deodorizing layer contains a functional material made of at least one of silica gel and zeolite, an acid hydrazide, and a binder. [2] The deodorizing material according to [1], wherein the material that accounts for the largest mass proportion of the materials constituting the support is inorganic fiber. [3] The deodorizing material according to [1] or [2], wherein the support is corrugated. [4] A step of applying or impregnating a support with a first slurry containing activated carbon and a binder; a first drying step of drying the support coated or impregnated with the first slurry; a step of applying and impregnating the support after the first drying step with a second slurry containing a functional material consisting of at least one of silica gel and zeolite, an acid hydrazide, and a binder; a second drying step in which the support coated or impregnated with the second slurry is dried; A method for manufacturing a deodorizing material, comprising: [5] The method for producing a deodorizing material according to [4], wherein the first slurry and the second slurry further contain a thickener. [6] The method for producing a deodorizing material according to [4] or [5], wherein the second slurry further contains activated carbon in an amount of 0.5 to 10% by mass relative to the functional material. [Effects of the Invention]

[0010] The deodorizing material of the present invention can utilize the effects of both activated carbon, which is effective against many odorous gas components but does not have the effect of removing aldehydes, and acid hydrazide, which has the effect of removing aldehydes. Furthermore, according to the method for producing a deodorizing material of the present invention, it is possible to produce a deodorizing material that utilizes both the effects of activated carbon, which is effective against many odorous gas components but does not have the effect of removing aldehydes, and acid hydrazide, which has the effect of removing aldehydes. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic partial cross-sectional view of a deodorizing material according to one embodiment of the present invention. [Figure 2] 1 is a plan view showing one embodiment of a support constituting a deodorizing material of the present invention. [Figure 3]FIG. 10 is a plan view showing another embodiment of the support constituting the deodorizing material of the present invention. [Figure 4] FIG. 1 is a diagram showing the results of Experimental Example 1. [Figure 5] FIG. 10 is a diagram showing the results of Experimental Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0012] In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0013] <Deodorizing material> 1 is a schematic partial cross-sectional view of a deodorizing material 1 according to one embodiment of the present invention. The deodorizing material 1 of this embodiment includes a support 10 and deodorizing agent layers 20 fixed to both sides of the support 10. The deodorant layer 20 is configured by sequentially bonding a first deodorant layer 21 and a second deodorant layer 22 from the support 10 side. It should be noted that FIG. 1 is a schematic view, and the interface between the first deodorizing agent layer 21 and the second deodorizing agent layer 22 does not exist as clearly as shown in the drawing.

[0014] [Support] The material constituting the support 10 is not particularly limited as long as it can adhere the material constituting the deodorant layer 20 and maintain its shape, and can be made of inorganic materials, organic materials, or a combination of these.

[0015] Furthermore, the material constituting the support 10 is preferably fibrous, since it can be easily made into a nonwoven fabric or a woven fabric and can easily absorb and retain the chemical solution by capillary action. In particular, a nonwoven fabric can be easily formed by wet papermaking. Examples of inorganic fibers include glass fibers, ceramic fibers, and carbon fibers. Among these, glass fibers are preferred in terms of safety to the human body and cost. Examples of organic fibers include pulp and resin fibers.

[0016] The support 10 preferably contains 30% by mass or more of inorganic fibers, more preferably 40% by mass or more, and even more preferably 50% by mass or more. By containing inorganic fibers, the support 10 can be provided with high heat resistance, high thermal insulation, non-flammability, etc. Of the materials constituting the support 10, the material that accounts for the largest mass ratio is preferably inorganic fiber. It is also preferable to use a combination of inorganic fibers and organic fibers in the support 10. By including organic fibers in addition to inorganic fibers, moldability is improved.

[0017] The basis weight of the support 10 is not particularly limited, but in the case of a nonwoven fabric, it is 10 to 100 g / m 2 It is preferable to set the thickness to 15 to 60 g / m 2 If the basis weight is equal to or greater than the lower limit of the preferred range, the strength of the nonwoven fabric and the support 10 obtained from the nonwoven fabric and molded into a corrugated shape or the like can be sufficiently obtained. If the basis weight is equal to or less than the upper limit of the preferred range, the thickness can be suppressed, and pressure loss can also be suppressed.

[0018] There is no particular limitation on the shape of the support 10, and a nonwoven fabric or the like may be used in a sheet form as is. In the case of a sheet form, it can be used as an air filter, as well as a deodorizing sheet or wallpaper for use in a room or car. When the deodorizing material 1 is used as an air filter, it is preferable to give it a corrugated shape like the cross section of cardboard or a pleated shape folded in a zigzag pattern, as this makes it easier to increase the contact area with air and maintain a stable shape.

[0019] Among these, the corrugated shape is preferred because it not only produces an air filter with low pressure loss, but also makes it easy to apply and impregnate the slurry to form the deodorizing agent layer 20 and dry it, allowing the deodorizing material 1 to be obtained with high productivity. As the corrugated shape, for example, a laminate of a liner member 15 and a corrugated member 16 can be used, as shown in the first sheet 11 of FIG. 2 and the second sheet 12 of FIG.

[0020] When used as an air filter, the pitch of the corrugated member 16 is preferably 2 to 8 mm, more preferably 4 to 6 mm, and the height of the corrugated member 16 is preferably 1 to 5 mm, more preferably 2 to 4 mm. The pitch and height of the corrugated members 16 do not need to be uniform, and for example, corrugated members 16 of different heights and pitches may be used for each stage. Furthermore, when corrugated members 16 of the same height and pitch are used for each stage, the phases may be the same or different.

[0021] When used as an air filter, the support 10 of the deodorizing material 1 may be formed by alternately stacking two or more layers of, for example, the first sheet 11 shown in Fig. 2 and the second sheet 12 shown in Fig. 3. In this case, it is preferable to stack the liner members 15 of the first sheet 11 and the liner members 15 of the second sheet 12 in a direction that intersects with each other in terms of contact efficiency with odorous gases.

[0022] [First deodorant layer] The first deodorizing agent layer 21 is a layer containing activated carbon and a binder. Activated carbon has a large surface area and pore volume, and therefore has the effect of removing odorous substances from general air due to its physical adsorption ability. The activated carbon used in this embodiment is preferably in powder form. Average particle size D of activated carbon measured by laser diffraction and scattering method 50 It is preferable that the particle size is 5 to 150 μm. However, since the above particle size range is an average particle size, activated carbon powders having particle sizes around this range are also included.

[0023] The specific surface area of ​​activated carbon powder (calculated by the BET method based on the amount of nitrogen adsorption) is 500 to 2000 m 2 / g is preferred. By making the specific surface area equal to or greater than the preferred lower limit, the contact area with air increases, and the amount of malodorous components adsorbed can be increased sufficiently.By making the specific surface area equal to or less than the preferred upper limit, a balance between cost and performance can be achieved.

[0024] As the binder, known inorganic binders and organic binders can be used. Examples of inorganic binders include colloidal silica, water glass, calcium silicate, alumina sol, alkoxysilane, etc. Examples of organic binders include emulsion-based organic binders, and in particular, acrylic emulsions such as acrylic resin, acrylic-styrene resin, acrylic-silicone resin, acrylic-urethane resin, vinyl acetate-acrylic resin, and polysiloxane-acrylic resin, and latex emulsions such as butadiene resin can be used. Among these, binders that have excellent adhesion properties to activated carbon and are unlikely to remain in the pores of activated carbon, such as water-based acrylic resins, are preferred.

[0025] The first deodorizer layer 21 may contain a thickener as a component contained in the slurry for forming the first deodorizer layer 21, in addition to the activated carbon and the binder. Examples of thickeners include sodium polyacrylate, acrylic copolymers, polyacrylic acid, carboxylic acid copolymers (ammonium salts), carboxylic acid copolymers (e.g., carboxylic acid copolymer sodium salts such as sodium carboxymethyl cellulose), cross-linked sodium polyacrylate, cross-linked acrylic polymers, and cross-linked polyacrylic acid. The first deodorizing agent layer 21 may contain, as necessary, a flame retardant, a colorant, a wetting agent, a paper strength improver, a water-resistant agent, a pH adjuster, an antifoaming agent, an antiseptic, an anti-mold agent, and the like.

[0026] [Second deodorant layer] The second deodorizing agent layer 22 is a layer containing a functional material, an acid hydrazide, and a binder. The functional material is selected from at least one of silica gel and zeolite, which do not impair the function of the acid hydrazide even when coexisting with the acid hydrazide. In second deodorizer layer 22, the acid hydrazide is thought to be present in a state supported by the functional material.

[0027] Acid hydrazides are used to deodorize aldehydes, and exhibit excellent chemical adsorption properties for acetaldehyde and the like. Examples of acid hydrazides include lauric acid hydrazide, salicylic acid hydrazide, formhydrazide, acetohydrazide, propionic acid hydrazide, p-hydroxybenzoic acid hydrazide, naphthoic acid hydrazide, 3-hydroxy-2-naphthoic acid hydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, diglycolic acid dihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, dimer acid dihydrazide, and 2,6-naphthoic acid dihydrazide. Of these, acid dihydrazides are preferred, succinic acid dihydrazide, adipic acid dihydrazide, and isophthalic acid dihydrazide are more preferred, and adipic acid dihydrazide is particularly preferred.

[0028] The functional material selected from at least one of silica gel and zeolite is a porous powder. Silica gel is an aggregate of primary particles whose main component is silicon dioxide, and can be obtained by various methods such as the gas phase method, the wet method (precipitation method), the sol-gel method, etc. Silica gel obtained by any method can be used as long as it has the desired properties. The silica gel serves as a carrier for the acid hydrazide.

[0029] Examples of zeolites include zeolite Y, zeolite X, and zeolite ZSM-5, among which zeolite Y is preferred because it has a high deodorizing effect per unit weight of acid hydrazide carried. Zeolite functions as a carrier for acid hydrazide and also as a deodorizing agent for acetic acid, methyl mercaptan, etc. By using zeolite, it is possible to supplement the function of activated carbon in first deodorizing agent layer 21.

[0030] As the functional material, silica gel is preferred because it is inexpensive. It is also preferred to use silica gel in combination with zeolite, which functions as a carrier for the acid hydrazide and also complements the function of activated carbon. Volume-based average particle diameter D of functional materials measured by laser diffraction and scattering method 50 It is preferable that the particle size is 5 to 150 μm. However, since the above particle size range is an average particle size, functional materials with particle sizes around this range are also included.

[0031] The specific surface area of ​​functional materials (calculated by the BET method based on the amount of nitrogen adsorption) is 50 to 700 m 2 / g is preferred, and 200 to 600m 2 / g is more preferred. When the specific surface area is equal to or greater than the preferred lower limit, the contact area between the supported acid hydrazide and air increases, and the amount of aldehyde gas adsorbed can be sufficiently increased.When the specific surface area is equal to or less than the preferred upper limit, the pore size does not become too small, and the acid hydrazide is not prevented from entering the pores.

[0032] As the binder, known inorganic binders and organic binders can be used. Specifically, the same binders as those listed as binders used in the first deodorant layer 21 can be used. Among these, binders that have excellent fixing properties for the functional material and are unlikely to remain in the pores of the functional material, such as water-based acrylic resins, are preferred.

[0033] The second deodorizer layer 22 may contain a thickener as a component contained in the slurry for forming the second deodorizer layer 22, in addition to the functional material, acid hydrazide, and binder. As the thickener, the same thickeners as those used in the first deodorant layer 21 can be used. The second deodorizing agent layer 22 may contain, as necessary, a flame retardant, a colorant, a wetting agent, a paper strength improver, a water resistance agent, a pH adjuster, an antifoaming agent, an antiseptic, an anti-mold agent, and the like. Activated carbon may be blended in the second deodorizer layer 22 within a range that does not impair the function of the acid hydrazide. The amount of activated carbon blended is 10% by mass or less, preferably 1 to 6% by mass, relative to the functional material.

[0034] [Other deodorizing ingredients] One or both of the first deodorizing agent layer 21 and the second deodorizing agent layer 22 may contain other deodorizing components to the extent that the functions of each layer are not impaired. Other deodorizing components include azole compounds and organic acids.

[0035] An azole compound is a five-membered ring aromatic compound containing at least one heteroatom, at least one of which is a nitrogen atom, and has the ability to adsorb aldehydes. The azole compound may be contained in either the first deodorizing agent layer 21 or the second deodorizing agent layer 22.

[0036] Organic acids are effective in deodorizing ammonia, trimethylamine, etc. Examples of organic acids include tartaric acid, malic acid, citric acid, lactic acid, succinic acid, maleic acid, phthalic acid, and nicotinic acid. When organic acids are used, they are preferably contained in the second deodorizer layer 22. Because organic acids are water-soluble, if they are contained in the first deodorizer layer 21, there is a concern that they may flow out when the slurry for forming the second deodorizer layer 22 is applied from above. Furthermore, if they are contained in the first deodorizer layer 21, they may be adsorbed by the activated carbon, which may prevent the activated carbon from adsorbing acidic malodorous components.

[0037] [Other aspects of deodorizing materials] The deodorizing material 1 shown in Figure 1 is in an embodiment in which the deodorizing layer 20 is formed on both sides of the support 10, but the deodorizing layer 20 may be formed on only one side of the support 10. The deodorant layer 20 is preferably formed entirely on one or both surfaces, but may be formed partially. Furthermore, the deodorizer layer 20 may have, in addition to the first deodorizer layer 21 and the second deodorizer layer 22, other deodorizer layers. When used as an air filter, the air filter may be made up of only the deodorizing material 1, but the air filter may also be made up of a combination of the deodorizing material 1 and another deodorizing material.

[0038] <Deodorizing material manufacturing method> The method for manufacturing a deodorizing material of this embodiment includes a step of applying and impregnating a support with a first slurry containing activated carbon and a binder, a first drying step of drying the support coated and impregnated with the first slurry, a step of applying and impregnating the support after the first drying step with a second slurry containing a functional material consisting of at least one of silica gel and zeolite, an acid hydrazide, and a binder, and a second drying step of drying the support coated and impregnated with the second slurry. A specific description will be given below using the deodorizing material 1 shown in FIG. 1 as an example.

[0039] [Manufacture of support] There are no particular limitations on the method for manufacturing the substrate 10 of the deodorizing material 1. When the substrate 10 is constructed by wet-laid papermaking to obtain a nonwoven fabric containing inorganic fibers, the weighted average fiber diameter of the inorganic fibers used is preferably 3 to 10 μm, more preferably 4 to 7 μm. If the weighted average fiber diameter is equal to or greater than the preferred lower limit, the substrate is safe for the human body. If the weighted average fiber diameter is equal to or less than the preferred upper limit, the resulting substrate has excellent strength. The weighted average fiber diameter is calculated by measuring the fiber diameters of 100 fibers by microscopic observation.

[0040] The weighted average fiber length of the inorganic fibers used is preferably 1 to 15 mm, more preferably 1 to 10 mm. If the weighted average fiber length is equal to or greater than the preferred lower limit, the strength of the resulting support is excellent. If the weighted average fiber length is equal to or less than the preferred upper limit, the formation of the resulting support is excellent. The length-weighted average fiber length is calculated by measuring the fiber lengths of 100 fibers by microscopic observation.

[0041] When the support 10 is constructed by obtaining a nonwoven fabric containing inorganic fibers and organic fibers by wet papermaking, the weighted average fiber diameter of the organic fibers used together with the inorganic fibers (excluding organic fibers that are used as binder components and do not retain their fibrous shape due to heating during production, etc.; the same applies below) is not particularly limited, but is preferably no more than three times, and more preferably no more than two times, the weighted average fiber diameter of the inorganic fibers.

[0042] When the weighted average fiber diameter of the organic fibers is three times or less the weighted average fiber diameter of the inorganic fibers, the effect of the organic fibers in reducing the rigidity of the support and the effect of improving the folding endurance tend to be improved. There is no particular lower limit for the weighted average fiber diameter of the organic fibers, but it is preferably 1 μm or more, more preferably 3 μm or more. The weighted average fiber diameter is calculated by measuring the fiber diameters of 100 fibers by microscopic observation.

[0043] The aspect ratio (ratio of weighted average fiber length to weighted average fiber diameter) of the organic fibers used together with the inorganic fibers is preferably 300 to 5000, more preferably 400 to 3000. If the aspect ratio is equal to or greater than the preferred lower limit, the effect of reducing rigidity is obtained and the folding strength is also increased, which tends to make the corrugated crests less likely to tear and to reduce the generation of paper dust. If the aspect ratio is equal to or less than the preferred upper limit, the fibers tend to be less likely to be bound.

[0044] The raw material slurry for obtaining a nonwoven fabric by wet papermaking contains inorganic fibers (mainly glass fibers) and, if necessary, organic fibers, and may optionally contain organic or inorganic binder components, auxiliaries, additives, fillers, etc. Water is usually used as the medium.

[0045] The organic binder component is a component that bonds fibers together. Examples of the organic binder component include thermoplastic resins that melt at least in part when heated during the production of the nonwoven fabric. The form of the organic binder component is not limited, and may be any of fibrous, particulate, emulsion, liquid, etc. Thermosetting resins can also be used as the organic binder component.

[0046] The inorganic binder component is not particularly limited, but examples thereof include colloidal silica, water glass, calcium silicate, silica sol, alumina sol, sepiolite, and alkoxysilane.

[0047] Wet papermaking can be carried out by preparing a raw material slurry containing the above-mentioned components and water (medium), and then making paper from the raw material slurry using a known papermaking machine. Examples of papermaking machines include cylinder papermaking machines, tilted papermaking machines, Fourdrinier papermaking machines, and short wire papermaking machines. Among these papermaking machines, multi-layer papermaking can be carried out using a combination of the same or different types of papermaking machines. There are also no particular limitations on the methods of dewatering and drying after papermaking.

[0048] In addition to adding the binder component to the raw material slurry, a liquid containing the binder component may be applied (external application) to the nonwoven fabric after papermaking by methods such as spray coating, curtain coating, impregnation coating, bar coating, roll coating, blade coating, etc. The nonwoven fabric to be externally applied may be a dried nonwoven fabric after drying, or a wet web before drying.

[0049] When the support 10 is to have a corrugated shape like the first sheet 11 and the second sheet 12, the obtained nonwoven fabric is subjected to a corrugating process to give it a wave shape (unevenness), thereby obtaining a corrugated member 16. Next, the obtained corrugated member 16 and a liner member 15 (non-corrugated nonwoven fabric) are bonded to produce a single corrugated body. Then, a plurality of single corrugated bodies can be stacked or formed into a cylindrical shape to form a corrugated shape.

[0050] To obtain a sheet-like support having a planar shape like the first sheet 11 in Figure 2 or the second sheet 12 in Figure 3 and a thickness in the thickness direction of the paper, the liner member 15 and the corrugated member 16 are laminated together, and then cut to a predetermined thickness in a plane perpendicular to the lamination direction. As described above, the first sheet 11 in FIG. 2 and the second sheet 12 in FIG. 3 may be alternately stacked in two or more layers and bonded to each other.

[0051] Examples of adhesives used for bonding the liner member 15 and the corrugated member 16, the first sheet 11 and the second sheet 12, etc. include inorganic adhesives such as colloidal silica, water glass, sepiolite, and alumina sol, and one or more of these can be used. Furthermore, organic adhesives such as ethylene-vinyl alcohol may also be used in combination as the adhesive. The support 10 may be used as is or may be fired before use.

[0052] [Formation of the first deodorant layer] The first deodorizing agent layer 21 can be formed on the support 10 through a process of applying and impregnating the support 10 with a first slurry, and a first drying process of drying the support coated and impregnated with the first slurry. The first slurry contains activated carbon and a binder. From the viewpoints of safety and workability, an aqueous solvent is preferred as the medium, and water is usually used.

[0053] Examples of raw materials for activated carbon include coconut shells, coal, wood, resins such as phenolic resin, old tires, etc. Pores in the activated carbon can be developed by heating and burning these raw materials, and then appropriately activating them with chemicals or gases, or appropriately washing them with acidic chemicals. After calcination and activation, the product is pulverized using a pulverizer such as a ball mill or a jet mill to obtain activated carbon powder.

[0054] The proportion of activated carbon in the first slurry is preferably 5 to 40 mass % and more preferably 10 to 30 mass % in terms of dry solid content. When the proportion of activated carbon in the first slurry is equal to or greater than the preferred lower limit, the time for the first drying step can be shortened. When the proportion of activated carbon in the first slurry is equal to or less than the preferred upper limit, excess liquid can be easily removed, a stable coating film can be easily obtained, and the dispersibility of activated carbon in the slurry can be easily ensured.

[0055] In preparing the first slurry, the activated carbon powder is preferably dispersed in a medium together with a thickener. The thickener is particularly suitable for use when it is difficult to constantly stir the first slurry when it is brought into contact with the support 10, or when the slurry separates into an emulsion containing water and binder components and activated carbon. The amount of thickener added varies depending on the type of thickener and is not particularly limited, and can be, for example, 0.1 to 10 mass %, 0.5 to 5 mass %, or 1.0 to 3 mass % relative to the activated carbon.

[0056] In preparing the first slurry, it is preferable to add the binder last to the slurry in which the activated carbon is dispersed, since adding the binder last can prevent the binder from penetrating into the pores of the activated carbon. The amount of binder added (solid content) varies depending on the type of binder, but is, for example, about 10 to 80% by mass, and preferably about 15 to 40% by mass, relative to the activated carbon.

[0057] When optional components such as other deodorizing components, flame retardants, colorants, wetting agents, paper strength improvers, water-resistant agents, pH adjusters, antifoaming agents, preservatives, and anti-mold agents are added to the first slurry, it is preferable to add these optional components to the slurry in which the activated carbon is dispersed before adding the binder.

[0058] As a method for applying and impregnating the first slurry onto the support 10, any known application method or impregnation method can be used, and is not particularly limited, but may be appropriately selected, such as immersing the support in a reservoir of the slurry, or submerging the support in a curtain of the slurry, etc. The application and impregnation steps may be performed multiple times.

[0059] The first slurry has an activated carbon amount per unit area of ​​the support 10 of 20 to 150 g / m 2 It is preferable to apply or impregnate the material so that the amount is 50 to 130 g / m 2 It is more preferable to apply or impregnate the material so that the above condition is satisfied. By ensuring that the amount of the first slurry applied or impregnated is equal to or greater than the preferred lower limit, the activated carbon can sufficiently remove malodorous components. By ensuring that the amount of the first slurry applied or impregnated is equal to or less than the preferred upper limit, excess liquid can be easily removed, ensuring a stable coating film.

[0060] After the step of applying and impregnating the first slurry, a first drying step is carried out. The temperature in the first drying step is preferably 40 to 180°C, and more preferably 100 to 150°C. When the temperature in the first drying step is equal to or higher than the preferred lower limit, the time for the first drying step can be shortened. When the temperature in the first drying step is equal to or lower than the preferred upper limit, the risk of activated carbon ignition can be reduced, allowing for safe production. The drying method in the first drying step is not particularly limited, and any known method can be used.

[0061] [Formation of second deodorant layer] The second deodorizing agent layer 22 can be formed by a first drying step, followed by a step of applying and impregnating the second slurry onto the support 10 on which the first deodorizing agent layer 21 has been formed, and a second drying step of drying the support coated and impregnated with the second slurry. The second slurry contains activated carbon and a binder. From the viewpoints of safety and workability, an aqueous solvent is preferred as the medium, and water is usually used.

[0062] The proportion of the functional material in the second slurry is preferably 10 to 40% by mass, and more preferably 20 to 30% by mass. When the proportion of the functional material in the second slurry is equal to or greater than the preferred lower limit, the time for the second drying step can be shortened. When the proportion of the functional material in the second slurry is equal to or less than the preferred upper limit, excess liquid can be easily removed, a stable coating film can be obtained, and the dispersibility of the functional material in the slurry can be easily ensured.

[0063] The proportion of the acid hydrazide in the second slurry is preferably 1 to 10% by mass, more preferably 3 to 6% by mass. When the proportion of the acid hydrazide in the second slurry is equal to or greater than the preferred lower limit, the adsorption performance is improved. When the proportion of the acid hydrazide in the second slurry is equal to or less than the preferred upper limit, dissolution during blending is facilitated.

[0064] The content of the acid hydrazide in the second slurry is preferably 5 to 40 mass % relative to the content of the functional material, and more preferably 10 to 30 mass %. When the ratio of the acid hydrazide to the content of the functional material in the second slurry is equal to or greater than the preferred lower limit, the effect of being supported on the functional material (improved adsorption rate) is exerted. When the ratio of the acid hydrazide to the content of the functional material in the second slurry is equal to or less than the preferred upper limit, the acid hydrazide relative to the functional material is optimized, which is economical.

[0065] In preparing the second slurry, the acid hydrazide is preferably dispersed in a medium together with the functional material, thereby making it possible to support the acid hydrazide on the functional material. Examples of methods for dispersing an acid hydrazide together with a functional material in a medium include a method in which the acid hydrazide is dissolved in a medium and then silica gel is added, a method in which silica gel is dispersed in a medium and then the acid hydrazide is added, and a method in which the acid hydrazide dissolved in a medium is sprayed onto silica gel, the silica gel is adsorbed, and the resulting mixture is dispersed in the medium.

[0066] The thickener is preferably added to the medium after the acid hydrazide and functional material are dispersed in the medium, which prevents the thickener from penetrating into the pores of the functional material before the acid hydrazide is supported in the pores. The thickener is particularly suitable for use when it is difficult to constantly stir the second slurry when it is brought into contact with the support 10 on which the first deodorizing agent layer 21 is formed, or when the slurry separates into an emulsion containing water and binder components and functional materials. The amount of thickener added varies depending on the type of thickener and is not particularly limited, and can be, for example, 0.1 to 10 mass %, 0.5 to 5 mass %, or 1.0 to 3 mass % relative to the functional material.

[0067] The second slurry may contain a small amount of activated carbon, if necessary, which improves the dispersibility of the functional material carrying the acid hydrazide. When activated carbon is contained in the second slurry, the content of activated carbon is preferably 0.5 to 10 mass % and more preferably 1 to 6 mass % based on the functional material as a dry solid content. When the content of activated carbon in the second slurry is equal to or greater than the preferred lower limit, the effect of improving dispersibility is easily obtained. When the content of activated carbon in the second slurry is equal to or less than the preferred upper limit, the degradation of the function of the acid hydrazide due to the activated carbon can be prevented. When a small amount of activated carbon is contained in the second slurry, it is preferable to add the activated carbon after dispersing the functional material and acid hydrazide, so that the acid hydrazide can be efficiently supported on the functional material.

[0068] In preparing the second slurry, it is preferable to add the binder last to the slurry in which the acid hydrazide, functional material, and, if necessary, thickener are dispersed. Adding the binder last can prevent the binder from penetrating into the pores of the functional material. The amount of binder added (solid content) varies depending on the type of binder, but is, for example, about 10 to 80% by mass, and preferably about 15 to 40% by mass, relative to the functional material.

[0069] When optional components such as other deodorizing components, flame retardants, colorants, wetting agents, paper strength improvers, water-resistant agents, pH adjusters, antifoaming agents, preservatives, and anti-mold agents are added to the second slurry, it is preferable to add these optional components to the slurry in which the acid hydrazide, functional material, and, if necessary, thickener are dispersed before adding the binder.

[0070] As a method for applying and impregnating the second slurry onto the substrate 10 on which the first deodorant layer 21 has been formed, any known application method or impregnation method can be used, and although there are no particular limitations, it is advisable to select an appropriate method such as immersing the substrate in a reservoir of the slurry or submerging the substrate in a curtain of the slurry. The application and impregnation process may be carried out multiple times.

[0071] The second slurry has an acid hydrazide content of 10 to 200 g / m 2 per unit area of ​​the support 10. 2 It is preferable to apply the coating so that the coating amount is 40 to 160 g / m 2 It is more preferable to apply or impregnate the material so that the above condition is satisfied. By setting the amount of the second slurry to be applied or impregnated at or above the preferred lower limit, the effect of removing aldehydes by the acid hydrazide can be sufficiently obtained. By setting the amount of the second slurry to be applied or impregnated at or below the preferred upper limit, the excess liquid can be easily removed, making it easier to ensure a stable coating film.

[0072] After the step of applying and impregnating the second slurry, a second drying step is carried out. The temperature in the second drying step is preferably 40 to 180°C, more preferably 100 to 150°C. When the temperature in the second drying step is equal to or higher than the preferred lower limit, the time for the second drying step can be shortened. When the temperature in the second drying step is equal to or lower than the preferred upper limit, the deterioration of the function of the acid hydrazide can be suppressed. The drying method in the second drying step is not particularly limited, and any known method can be used.

[0073] [Action and effect] According to the production method of this embodiment, the acid hydrazide is contained in a layer separate from the activated carbon, and therefore the deterioration of the function of the acid hydrazide due to the activated carbon is suppressed. Furthermore, if the second slurry containing the acid hydrazide is applied or impregnated before the first slurry containing the activated carbon, there is a concern that the water-soluble acid hydrazide may be eluted. However, in the production method of the present embodiment, the second slurry is applied or impregnated after the first slurry containing the activated carbon, and therefore such a concern does not arise.

[0074] Furthermore, because first deodorizer layer 21 does not contain acid hydrazide, which is likely to lose its functionality when heated in the presence of activated carbon, the first drying step in forming first deodorizer layer 21 can be carried out at a sufficiently high temperature. Therefore, moisture in the activated carbon can be sufficiently removed in a short time. Furthermore, since the second deodorizer layer 22 does not substantially contain activated carbon, the second drying step can be carried out at an appropriate temperature when forming the second deodorizer layer 22. This makes it easy to prevent the function of the acid hydrazide from being reduced by heating. [Example]

[0075] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following description.

[0076] <Measurement method> [Deodorizing performance] The deodorizing performance of the filters (adsorbents) of the Examples and Comparative Examples was measured as follows. First, the test vessel (internal volume 1 m 3 An acrylic wind tunnel (with a fan) was set in the acrylic chamber, and each filter was installed in the wind tunnel. The components to be removed were then injected into the test vessel so that the initial concentration of the components in the gas (test gas) in the test vessel was approximately 10 ppm, and the fan was then operated to ventilate the test gas through the filter at a wind speed of 1.74 m / s for 30 minutes.

[0077] The concentration of the component to be removed before injection of the component to be removed (BG), the concentration of the component to be removed before injection of the component to be removed into the test container and ventilation begins (D0), and the concentration of the component to be removed after ventilation for 30 minutes (D 30 ) were measured respectively. For the measurements, in Experimental Example 1, a photoacoustic gas monitor INNOVA 1512-5 manufactured by LumaSense Technologies was used, and in Experimental Examples 2 to 4, a gas detector tube 92L (for acetaldehyde) manufactured by Gastec Corporation was used.

[0078] In Experimental Example 1, the initial concentration (C0) and the concentration after ventilation (C 30 ) was sought. C0=D0-BG (1) C 30 =D 30 -BG (2)

[0079] On the other hand, in Experimental Examples 2 to 4, BG = 0 was assumed, and the initial concentration (C0) and the concentration after ventilation (C 30 ) was sought. C0=D0···(1)' C 30 =D 30 (2)' It was considered that.

[0080] The initial concentration (C0) and the concentration after ventilation ( C0 ) and the adsorption amount and removal rate were calculated using the following (3) and (4). Adsorption amount (ppm)=C0-C 30 ···(3) Removal rate (%)=(C0-C 30 )÷C0×100 (4)

[0081] [Surface temperature] The surface temperature of the filter (adsorbent) of each example and comparative example in Experimental Example 2 was calculated as the average of temperatures measured at five locations, including the four corners and the center, using a radiation thermometer SK-8300 manufactured by Sato Keiki Seisakusho Co., Ltd.

[0082] <Support> The support in the filter (adsorbent) in each example and comparative example was glass paper PHN-50G (glass nonwoven fabric made of glass fiber and pulp, basis weight 50 g / m) manufactured by Oji F-Tex. 2 ) was used, which had a corrugated shape equivalent to that of the first sheet 11 in Figure 2 (100 mm long x 100 mm wide, 10 mm thick, approximately 70 cells per square inch. The pitch of the corrugated member 16 was 5.9 mm, and the height was 3.5 mm).

[0083] <Slurry composition> [Raw materials] The slurries used in the examples and comparative examples were prepared using the following raw materials. Activated carbon: Powdered activated carbon SA1000, manufactured by Futamura Chemical Co., Ltd., moisture content 50% by mass CMC: carboxymethyl cellulose. Binder: styrene-acrylic resin. pH adjuster: organic acid. Acid hydrazide: Adipic acid hydrazide. Y-type: Y-type zeolite. ZSM-5 type: ZSM-5 type zeolite. Silica gel: Mizukasil (registered trademark) P-758C, manufactured by Mizusawa Industrial Chemicals.

[0084] [Preparation of mixed slurry] Slurry H was prepared using the raw materials having the composition shown in Table 1 (unit: solid content parts by mass) according to the following procedure. First, acid hydrazide was dissolved in water, then Y-type zeolite, ZSM-5-type zeolite, and silica gel were dispersed in it. Activated carbon and CMC were then added and dispersed, followed by a pH adjuster, and finally a binder.

[0085] [Preparation of first slurry] Slurries 1-1 to 1-3 were prepared using raw materials having the compositions (unit: solid parts by mass) shown in Table 1, according to the following procedure. First, activated carbon and CMC were added to water and dispersed, and then the binder was added.

[0086] [Preparation of second slurry] Slurries 2-1 to 2-6 were prepared using raw materials having the compositions (unit: solid parts by mass) shown in Table 1, according to the following procedure. First, acid hydrazide was dissolved in water, then Y-type zeolite or silica gel, activated carbon, and CMC were added and dispersed. Then, a pH adjuster was added, and finally, a binder was added.

[0087] [Table 1]

[0088] <Experimental Example 1> The acetaldehyde removal effect was compared between impregnating the support with the first slurry, drying it, and then impregnating and drying the second slurry, and between impregnating the support directly with the second slurry and drying it.

[0089] [Examples 1-1 to 1-3] For the first layer, 7.4 g of Slurry 1-3 (impregnated amount of the entire slurry including water) was directly impregnated into the support. After impregnation, the support was heated and dried at 150°C for 15 minutes to form a first deodorant layer. Thereafter, as a second layer, Slurry 2-3 was impregnated into the support on which the first deodorizing layer had been formed, so that the acid hydrazide content in the entire deodorizing layer was the amount shown in Table 2. After impregnation, the filter was heated and dried at 150°C for 10 minutes to form a second deodorizing layer, thereby obtaining the filter of each Example. Table 2 shows the deodorizing performance of each Example when the component to be removed was aldehyde. Furthermore, Figure 4 shows the relationship between the amount of acid hydrazide and the amount of aldehyde adsorbed for each Example.

[0090] [Comparative Examples 1-1 to 1-11] The support was directly impregnated with the slurry shown in Table 2 so that the acid hydrazide content in the entire deodorant layer was the amount shown in Table 2. After impregnation, the filter was heated at 150°C for 10 minutes and dried to obtain a filter for each comparative example. Table 2 shows the deodorizing performance of each comparative example when the component to be removed was aldehyde. The relationship between the amount of acid hydrazide and the amount of aldehyde adsorbed for each comparative example is also shown in Figure 4.

[0091] [Table 2]

[0092] As shown in Table 2 and FIG. 4, it was confirmed that the aldehyde removal performance of the acid hydrazide is not impaired even when a second deodorizing layer containing an acid hydrazide is formed on a first deodorizing layer containing activated carbon, as in the examples. Furthermore, when compared at the same acid hydrazide content (acid hydrazide content in the entire deodorant layer), the Example in which a second deodorant layer containing acid hydrazide was formed on a first deodorant layer containing activated carbon exhibited higher aldehyde removal performance than the Comparative Example in which a deodorant layer containing acid hydrazide was formed directly on a support. While the reason for this is unclear, it is thought that even the first deodorant layer, which has almost no aldehyde removal performance, was able to capture some aldehyde. It is also possible that the presence of the first deodorant layer improved the aldehyde removal performance of the second deodorant layer. It is also possible that the acid hydrazide was distributed more widely on the surface of the second deodorant layer, improving acetaldehyde removal performance.

[0093] <Experimental Example 2> The effect of heating on the acetaldehyde removal efficiency was compared between two cases: when the support was impregnated with the first slurry and dried, and then the second slurry and dried, and when the support was directly impregnated with a slurry containing both acid hydrazide and activated carbon and dried.

[0094] [Examples 2-1 to 2-7] As the first layer, 20 g of Slurry 1-2 was directly impregnated into the support, which was then heated and dried at 150° C. for 15 minutes to form a first deodorant layer.

[0095] Then, as the second layer, 14 g of Slurry 2-6 (the acid hydrazide content in the entire deodorant layer was 0.8 g) was impregnated into the support on which the first deodorant layer had been formed. After impregnation, the support was heated and dried at 150°C for 10 minutes to form a second deodorant layer, and the filter of each Example was obtained. The obtained filter was further heated to accelerate degradation at the set temperature and for the time shown in Table 3. In Example 2-1, further heating to accelerate degradation was not performed. The surface temperature at the end of heating and the deodorizing performance of each example when the component to be removed was aldehyde are shown in Table 3. The relationship between the surface temperature and the aldehyde removal rate for each example is shown in Figure 5.

[0096] [Comparative Examples 2-1 to 2-7] The support was directly impregnated with 24 g of Slurry H (the acid hydrazide content in the entire deodorant layer was 0.5 g). After impregnation, the support was heated and dried at 105°C for 30 minutes to form a deodorant layer, and filters of each comparative example were obtained. The obtained filter was further heated to accelerate the deterioration at the set temperature and for the time shown in Table 3. In Comparative Example 2-1, further heating to accelerate the deterioration was not performed. The surface temperature at the end of heating and the deodorizing performance of each comparative example when the component to be removed was aldehyde are shown in Table 3. The relationship between the surface temperature and the amount of aldehyde adsorbed for each comparative example is shown in Figure 5.

[0097] [Table 3]

[0098] As shown in Table 3 and Figure 5, when a second deodorizer layer containing an acid hydrazide was formed on a first deodorizer layer containing activated carbon, as in the examples, the effect of heating on the aldehyde removal performance of the acid hydrazide was small. In contrast, in the comparative example in which slurry H containing both acid hydrazide and activated carbon was impregnated, it was confirmed that the influence of heating was large, and that the influence of heating at high temperatures was particularly large.

[0099] <Experimental Example 3> It has been confirmed that the present invention can achieve a sufficient effect of removing acetaldehyde even when the composition of the slurry is changed in various ways.

[0100] [Examples 3-1 to 3-4] For the first layer, the support was directly impregnated with the slurry shown in Table 4 in the impregnation amount shown in Table 4. After impregnation, the support was heated at 150°C for 15 minutes and dried to form a first deodorant layer. Thereafter, as the second layer, the support on which the first deodorizing agent layer had been formed was impregnated with the slurry shown in Table 4 in the impregnation amount shown in Table 4. After impregnation, the support was heated and dried at 150°C for 15 minutes to form a second deodorizing agent layer, and the filter of each Example was obtained. Table 4 shows the contents of activated carbon and acid hydrazide contained in the entire deodorant layer, and the deodorizing performance of each example when the component to be removed was aldehyde.

[0101] [Comparative Example 3-1] The support was directly impregnated with Slurry H in the amount shown in Table 4. After impregnation, the support was dried by heating at 105°C for 30 minutes to obtain a filter of Comparative Example 3-1. Table 4 shows the contents of activated carbon and acid hydrazide contained in the entire deodorant layer, and the deodorizing performance of Comparative Example 3-1 when the component to be removed was aldehyde.

[0102] [Table 4]

[0103] As shown in Table 4, all of the Examples showed significantly better aldehyde removal performance than the Comparative Examples.

[0104] <Experimental Example 4> It has been confirmed that the present invention does not impair the toluene removal performance even when the composition of the slurry is changed in various ways.

[0105] [Examples 4-1 to 4-7] For the first layer, the support was directly impregnated with the slurry shown in Table 5 in the impregnation amount shown in Table 5. After impregnation, the support was heated at 150°C for 15 minutes and dried to form a first deodorizing agent layer. Thereafter, as the second layer, the support on which the first deodorizing agent layer had been formed was impregnated with the slurry shown in Table 5 in the impregnation amount shown in Table 5. After impregnation, the support was heated and dried at 150°C for 15 minutes to form a second deodorizing agent layer, and the filter of each Example was obtained. Table 5 shows the contents of activated carbon and acid hydrazide contained in the entire deodorant layer, and the deodorizing performance of each example when the component to be removed was toluene.

[0106] [Comparative Example 4-1] The support was directly impregnated with Slurry H in the amount shown in Table 5. After impregnation, the support was dried by heating at 105°C for 30 minutes to obtain a filter of Comparative Example 4-1. Table 5 shows the contents of activated carbon and acid hydrazide contained in the entire deodorant layer, and the deodorizing performance of Comparative Example 4-1 when the component to be removed was toluene.

[0107] [Table 5]

[0108] As shown in Table 5, all of the Examples maintained the same toluene removal performance as the Comparative Example. [Explanation of symbols]

[0109] 1. Deodorizing material 10 Support 11 Sheet 1 12 Second Sheet 15 Liner material 16 Corrugated material 20 Deodorizing layer 21 First deodorant layer 22 Second deodorant layer

Claims

[Claim 1] A support, a first deodorizing agent layer and a second deodorizing agent layer sequentially fixed to the support, the first deodorizing agent layer contains activated carbon and a binder, The second deodorizing agent layer contains a functional material made of at least one of silica gel and zeolite, an acid hydrazide, and a binder.

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