JP7546509B2 - Granulated charcoal and its manufacturing method, air purifier filter, and air purifier - Google Patents

Description

The present invention relates to granulated charcoal and its manufacturing method, an air purifier filter, and an air purifier.

In recent years, environmental society has become increasingly concerned with odor pollution countermeasures. For example, pollution caused by exhaust gases has become a problem with odor pollution. Examples of odorous substances include acid gases, aldehyde gases, basic gases, and sulfur-based neutral gases. In the field of exhaust gas treatment, which removes these gases, there is a demand for air purification functionality as well as antibacterial and antiviral functionality. In order to adsorb and remove various odorous substances, adsorbents such as activated carbon impregnated with chemicals (chemical substances) corresponding to each odorous substance are used.

Methods of adding these functionalities to activated carbon include an adsorbent in which a saturated cyclic secondary amine (piperidine, morpholine, etc.) is supported (impregnated) on a porous carrier of activated carbon (Patent Document 1), and an adsorbent in which a hydroxyamine compound and an amine compound other than a hydroxyamine compound are impregnated on a porous carrier of activated carbon (Patent Document 2). However, this impregnation method is limited to drugs that are soluble in water or organic solvents, and is therefore not very versatile.

Therefore, in addition to the above-mentioned impregnation techniques, a post-granulation technique is known in which a powdered adsorbent and a chemical are mixed using a binder. This post-granulation technique allows a larger amount of chemical to be introduced than the impregnation technique, and the resulting granulated carbon is known to have higher removal performance, such as being able to remove not only various toxic gases but also mixed gases, without the problems of the impregnated carbon obtained by the impregnation technique (Patent Document 3). Granulated carbon is obtained by mixing activated carbon and various chemicals, etc., using a binder, granulating, and hardening.

Patent No. 3253323 JP 2018-114463 A Patent No. 5430987

However, the granulated coal obtained by the post-granulation technology of Patent Document 3 has issues with hardness and abrasion resistance as an adsorbent.

For example, when the adsorbent is used in an air purifier filter, it is required to have a high packing density. In other words, if the packing density of granulated charcoal is low, the layer height will be high when the adsorbent is packed by mass, which will increase the pressure loss and affect the breathability. It is therefore possible to pack the adsorbent by volume, but when packed in this way, there is a problem that the amount of packed adsorbent is reduced and the adsorption performance per volume is not achieved.

The present invention has been made in consideration of these problems, and aims to provide granulated charcoal that has sufficient adsorption performance for odorous gases, is excellent in hardness and abrasion resistance, and can be packed at a high packing density into air purifier filters and the like, a manufacturing method thereof, an air purifier filter, and an air purifier.

As a result of extensive research into achieving the above object, the inventors discovered that by using granulated charcoal that is cylindrical with an upper surface, a side surface, and a lower surface, and in which the edges between the upper surface and the side surface and/or the edges between the lower surface and the side surface are curved, the granulated charcoal has sufficient adsorption performance for odorous gases, is excellent in hardness and abrasion resistance, and can be packed at a high packing density in filters for air purifiers, etc., and thus completed the present invention.

That is, the present invention includes the following embodiments:

[1] Granulated coal having a cylindrical shape having an upper surface, a side surface, and a lower surface, wherein the edge between the upper surface and the side surface, and/or the edge between the lower surface and the side surface are curved.
[2] Granulated coal as described in [1], wherein the length of the curved surface of the edge portion in the radial direction of the upper surface is _R1 , the length of the curved surface of the edge portion in the radial direction of the lower surface is _R2 , and r is the radius of the circular cross-section having the largest area among the circular cross-sections of the cylinder parallel to the radial direction of the upper surface, the average value of _R1 /r and _R2 /r is 0.20 or more.
[3] The granulated coal according to [1] or [2], in which L/D is 3.0 or less, where L is the length of the central axis of the cylinder and D is the diameter of the circular cross section having the largest area among the circular cross sections of the cylinder parallel to the radial direction of the upper surface.
[4] The granulated coal according to any one of [1] to [3], wherein the performance X represented by the following formula (1) is 125 or more.
Performance X=(E/(30/ρ))×100...(1)
(In formula (1), E represents the initial removal rate (%) obtained by the JEMA 1467 deodorizing performance test method, and ρ represents the packing density (g/cm ³ ) of the granulated carbon).
[5] The granulated coal according to any one of [1] to [4], having a hardness of 95% or more obtained in accordance with JIS K1474.
[6] The granulated carbon according to any one of [1] to [5], wherein the granulated carbon is obtained by kneading activated carbon powder, functional powder, and an aqueous emulsion containing an organic binder resin, granulating the mixture, sizing the mixture, and hardening the mixture.
[7] The granulated carbon according to [6], wherein the specific surface area of the activated carbon powder is less than 1400 m ² /g.
[8] The granulated carbon according to any one of [1] to [5], wherein the granulated carbon is obtained by kneading activated carbon powder, a functional powder, an aqueous emulsion containing an organic binder resin, and a metal oxide, granulating, sizing, and hardening the mixture, and the specific surface area of the activated carbon powder is 1,400 ^m2 /g or more.
[9] The granulated carbon according to [8], wherein the specific gravity of the metal oxide is 2.5 or more.
[10] The granulated carbon according to [8] or [9], wherein the metal oxide is at least one selected from the group consisting of iron oxide, copper oxide, zinc oxide, and aluminum oxide.
[11] The granulated carbon according to any one of [6] to [10], wherein the functional powder contains sulfanilic acid.
[12] The granulated carbon according to any one of [6] to [11], wherein the average particle diameter (D50) of the functional powder is 30 μm or less.
[13] The granulated carbon according to any one of [6] to [12], wherein the average particle diameter (D50) of the organic binder resin is 1 μm or less.
[14] A filter for an air purifier, comprising the granulated charcoal according to any one of [1] to [13].
[15] An air purifier comprising the granulated charcoal according to any one of [1] to [13].
[16] A method for producing granulated charcoal according to any one of [1] to [13], comprising the steps of kneading activated carbon powder, a functional powder, an aqueous emulsion containing an organic binder resin, and, if necessary, a metal oxide, granulating the mixture obtained in the kneading step, sizing the granulated product obtained in the granulating step, and hardening the sizing product obtained in the sizing step, wherein the sizing step is a step of sizing the granulated product using a spherical sizing machine.

The present invention provides granulated charcoal that has sufficient adsorption performance for odorous gases, is excellent in hardness and abrasion resistance, and can be packed at a high packing density into air purifier filters, etc., as well as a manufacturing method thereof, an air purifier filter, and an air purifier.

FIG. 2 is a schematic diagram for explaining granulated coal according to the present invention. FIG. 2 is an enlarged view of the upper surface portion in FIG. FIG. 2 is another schematic diagram for explaining granulated coal according to the present invention.

The following describes in detail the embodiment of the present invention (hereinafter, simply referred to as the "present embodiment"). Note that the following present embodiment is an example for explaining the present invention, and the present invention is not limited to only this embodiment.

[Granulated coal]
The granulated charcoal of this embodiment has a cylindrical shape having an upper surface, a side surface, and a lower surface, and the edge between the upper surface and the side surface and/or the edge between the lower surface and the side surface are curved. When the edge is curved in the cylindrical shape, troubles caused by damage to the granulated charcoal due to dust generated from the granulated charcoal and collisions between the granulated charcoal and the like can be prevented when the granulated charcoal is used in an air purifier filter or the like. In addition, the granulated charcoal can be packed in a container and a filter at a high density. Therefore, when the adsorbent is packed on a mass basis, the layer height is not reached and pressure loss can be kept low, so that good breathability can be provided. In addition, when the adsorbent is packed on a volume basis, a large amount of the adsorbent can be packed, so that high adsorption performance can be exhibited per volume.

Next, the shape of the granulated coal of this embodiment will be generally described with reference to FIGS.
As shown in Figures 1 and 2, the granulated coal has a cylindrical shape having an upper surface 1, a side surface 2, and a lower surface 3, and an edge 4 between the upper surface 1 and the side surface 2 and/or an edge 4 between the lower surface 3 and the side surface 2 are curved surfaces. In this embodiment, as shown in Figure 3, the upper surface 1 and the lower surface 2 are each a point, that is, the granulated coal also includes a granulated coal having a cylindrical shape and a shape in which the upper and lower parts of the cylindrical shape are hemispherical. The granulated coal may have a shape in which either the upper part or the lower part is hemispherical.

In this embodiment, the cylindrical shape does not necessarily have to be a strict cylinder in terms of geometry, and includes cylindrical shapes whose cross-sectional shape in a plane perpendicular to the central axis of the cylinder (hereinafter simply referred to as "cross-sectional shape") is oval, right circular, or elliptical, and also includes cylinders that are slightly curved or have a slightly uneven surface. In this embodiment, a right circular or elliptical shape means, for example, a shape whose ratio of the major axis to the minor axis (major axis/minor axis) is 3 or less. As the cross-sectional shape, a circle or an ellipse is preferable because it makes it possible to pack granulated coal at a higher density in containers and filters.

The cross-sectional shapes of the upper surface 1 and the lower surface 3 can be, for example, circular, oval, right circular, and elliptical. Among these, circular and elliptical shapes are preferred because they allow the granulated coal to be packed more densely into containers and filters.

1 and 2, the granulated charcoal has curved edges 4 between the upper surface 1 and the side surface 2 and/or edges 4 between the lower surface 3 and the side surface 2. Among these, it is preferable that both edges 4 between the upper surface 1 and the side surface 2 and edges 4 between the lower surface 3 and the side surface 2 are curved, since this allows the granulated charcoal to be packed more densely in containers, filters, etc.
In this embodiment, the edge 4 between the upper surface 1 and the side surface 2 refers to the connection portion between the periphery of the upper surface 1 and the upper periphery of the side surface 2, and the shape of the connection portion is a convex curved surface. The curvatures of the curved surfaces may all be the same or different. Similarly, the edge 4 between the lower surface 3 and the side surface 2 refers to the connection portion between the periphery of the lower surface 3 and the lower periphery of the side surface 2, and the shape of the connection portion is a convex curved surface. The curvatures of the curved surfaces may all be the same or different.

1 and 2, when the length of the curved surface of the edge 4 in the radial direction of the upper surface 1 is _R1 , the length of the curved surface of the edge 4 in the radial direction of the lower surface 2 is _R2 , and the radius of the circular cross section having the largest area among the circular cross sections of a cylinder parallel to the radial direction of the upper surface 1 is r, the average value of _R1 /r and _R2 /r is preferably 0.20 or more, more preferably 0.25 or more, and even more preferably 0.30 or more. The upper limit of the average value of _R1 /r and _R2 /r is not particularly limited, but is 1 or less in consideration of the shape of the granulated coal.
With regard to R ₁ /r and R ₂ /r, it is more preferable that either one of the numerical ranges is within the above-mentioned numerical range, and it is even more preferable that both of the numerical ranges are within the above-mentioned numerical ranges.

In this embodiment, the radial direction means the radius of the circle when the cross-sectional shape of the upper surface 1 and the lower surface 3 is circular. In the case of a circle, _R1 and _R2 mean the length of the curved surface along the radius. On the other hand, when the shape of the upper surface 1 and the lower surface 3 is an egg shape, an oval shape, or an ellipse shape, the radial direction means the longest direction (i.e., the long axis direction) in those shapes. In addition, _R1 and _R2 mean the length of the curved surface along the long axis. In this embodiment, the circle includes not only a perfect circle, but also an egg shape, a right circle, and an ellipse.

When the average value of _R1 /r and _R2 /r is within the above range, the hardness and abrasion resistance tend to be excellent. In addition, the granulated charcoal can be packed in a container, a filter, etc. at a higher density, which gives better air permeability and tends to enable the adsorption performance to be further improved.

As shown in Fig. 1, when the length of the central axis of the cylinder is L and the diameter of the circular cross section having the largest area among the circular cross sections of the cylinder parallel to the radial direction of the upper surface 1 is D, the granulated coal preferably has an L/D of 3.0 or less, more preferably an L/D of 2.5 or less, and further preferably an L/D of 2.0 or less. The lower limit of L/D is not particularly limited, but is 1 or more in consideration of the shape of the granulated coal.
When L/D is within the above range, the granulated coal can be packed more densely into containers, filters, etc., and therefore better breathability can be imparted, and there is a tendency for even higher adsorption performance to be exhibited.

Although it depends on the application, the value of L in L/D is preferably 6 mm or less, more preferably 5 mm or less, and even more preferably 4 mm or less, because granulated coal can be packed at a higher density in containers, filters, etc. If L exceeds 6 mm, the packing density of granulated coal in containers, filters, etc. tends to be lower. There is no particular limit to the lower limit of L, but it is 2 mm or more, taking into account the shape of the granulated coal.

Although it varies depending on the application, the value of D in the L/D ratio is preferably 4 mm or less. The lower limit of D is preferably 1 mm or more, and more preferably 1.5 mm or more. When the value of D is within the above range, the contact efficiency between the granulated charcoal and the adsorbed gas becomes better, and sufficient removal performance tends to be exhibited. Furthermore, when the value of D is within the above range, the granulated charcoal has a more suitable size and hardness, so that clogging and breakage tend to occur less when the granulated charcoal is filled into containers, filters, etc.

In this embodiment, R ₁ , R ₂ , r, L, and D can be measured by a known method. Examples of such methods include measurement using a measuring tool such as a caliper, and measurement using a tape measure on the enlarged image of the granulated coal after enlarging it with an optical microscope or an electron microscope. The number of measurements is not particularly limited, but is usually set to about 20 times. For specific measurement methods, see the examples.

Since the granulated charcoal has sufficient adsorption performance for odorous gases, the performance X shown in the following formula (1) is preferably 125% or more, more preferably 130% or more, and even more preferably 135% or more. Examples of odorous gases include acidic gases such as aldehyde gas, basic gases such as ammonia gas, and sulfur-based neutral gases. In this embodiment, the performance X indicates the adsorption performance when the granulated charcoal is filled in a container and a filter, etc., on a volume basis, and the higher the performance X, the better the adsorption performance on a volume basis.

Performance X=(E/(30/ρ))×100...(1)
In the formula (1), E represents the initial removal rate (%) obtained by the JEMA 1467 deodorizing performance test method, and ρ represents the packing density (g/cm ³ ) of the granulated carbon.

If the performance X is less than 125%, it is suggested that the adsorption performance as an adsorbent is lower and the packing density of the granulated carbon is lower, and the adsorbent tends not to have sufficient performance as an adsorbent used in air purifier filters, etc.
For a specific method of calculating the performance X, see the Examples.

The hardness of the granulated charcoal measured in accordance with JIS K1474 is preferably 95% or more, and more preferably 97% or more. If the hardness is within the above range, problems caused by damage to the granulated charcoal due to dust generated from the granulated charcoal and collisions between the granulated charcoal particles, etc., can be further prevented when the granulated charcoal is used in air purifier filters, etc. For specific methods for measuring hardness, please refer to the examples.

Granulated carbon is made by kneading activated carbon powder, functional powder, an aqueous emulsion containing an organic binder resin, and, if necessary, metal oxide, granulating the mixture, sizing it, and hardening it.

(Activated carbon powder)
As the activated carbon powder, various activated carbon powders can be used. Examples of activated carbon include plant-based raw materials or fossil-based raw materials such as wood, wood flour, coconut shells, by-products during pulp production, bagasse, blackstrap molasses, coal (peat, lignite, brown coal, bituminous coal, etc.), anthracite, petroleum distillation residue components, petroleum pitch, coke, and coal tar; various synthetic resins such as phenol resin, vinyl chloride resin, vinyl acetate resin, melamine resin, urea resin, resorcinol resin, celluloid, epoxy resin, polyurethane resin, polyester resin, acrylic resin, and polyamide resin; synthetic rubbers such as polybutylene, polybutadiene, and polychloroprene; other synthetic wood; and activated carbons made from synthetic pulp. Among these, activated carbons made from coal and coconut shells are preferred. These activated carbons can be used alone or in combination of two or more.

The activated carbon may be activated carbon obtained by carbonizing or infusible the above-mentioned raw materials as necessary, and then activating them. The carbonization method, infusibility method, and activation method are not particularly limited, and conventional methods can be used. Examples of activation methods include a gas activation method in which the carbon raw material (or its carbonized or infusible material) is heat-treated at about 500 to 1000°C in an activation gas (steam, carbon dioxide, etc.), and a chemical activation method in which the carbon raw material (or its carbonized or infusible material) is mixed with an activator (phosphoric acid, zinc chloride, potassium hydroxide, sodium hydroxide, etc.) and heat-treated at about 300 to 800°C. The activated carbon obtained by the activation treatment may be used as it is. The activated carbon obtained by the activation treatment may also be used after washing with acid or water and heat treatment to remove attached components and surface functional groups of the activated carbon.

The specific surface area of the activated carbon powder is preferably 600 to 2200 m ² /g, more preferably 1000 to 2000 m ² /g, and even more preferably 1200 to 1650 m ² /g. When the specific surface area of the activated carbon powder is within the above range, it tends to have sufficient adsorption performance for odorous gases and excellent hardness. The specific surface area of the activated carbon is measured based on the BET method. For specific measurement methods, please refer to the Examples.

When the specific surface area of the activated carbon powder is greater than the lower limit, it tends to function more adequately as an adsorbent for odorous gases. On the other hand, when the specific surface area of the activated carbon powder is less than the upper limit, it tends to have a higher packing density in containers, filters, etc., which provides better breathability and tends to provide even higher adsorption performance.

In this embodiment, when activated carbon powder having a specific surface area of less than 1,400 ^m2 /g is used, the granulated carbon can be packed more densely into containers, filters, etc., and it tends to be possible to achieve higher adsorption performance per volume.

When using activated carbon powder with a specific surface area of 1400 ^m2 /g or more, it is preferable to use a metal oxide together with the activated carbon in the production of granulated carbon in order to further increase the packing density in containers, filters, etc. By using a metal oxide, the packing density in containers, filters, etc. can be further increased, which tends to provide good breathability and further enhance high adsorption performance.

The average particle size (D50) of the activated carbon powder is preferably 20 to 30 μm, since the granulated carbon can be packed more densely into containers and filters. If the average particle size (D50) is 20 μm or more, the hardness of the granulated carbon is further increased, and clogging and breakage can be suppressed when packing the granulated carbon into containers and filters. In addition, while it is possible to increase the amount of binder used to suppress a decrease in hardness, if the average particle size (D50) is 20 μm or more, it is possible to prevent the binder from reducing the adsorption performance. If the average particle size (D50) is 30 μm or less, the granulated carbon tends to be packed more densely into containers and filters.

In this embodiment, the average particle size (D50) is measured as a volume-based median size using a laser diffraction light scattering particle size distribution measuring device. For specific measurement methods, see the Examples.

(Metal Oxides)
In order to further increase the packing density in containers, filters, etc., the metal oxide preferably has a specific gravity of 2.5 or more, more preferably 3.0 or more, and even more preferably 3.5 or more. The upper limit of the specific gravity is not particularly limited, but is 10 or less in consideration of the packing density of the granulated carbon in containers, filters, etc.

The average particle size (D50) of the metal oxide is preferably 10 to 50 μm, since this allows the granulated charcoal to be packed more densely into containers, filters, etc.

As metal oxides, iron oxide, copper oxide, zinc oxide, and aluminum oxide are preferred because they can further increase the packing density in containers and filters without impairing the adsorption performance for odorous gases. These metal oxides can be used alone or in combination of two or more.

The amount of metal oxide used is preferably 5 to 15 parts by mass, and more preferably 7 to 13 parts by mass, per 100 parts by mass of powdered activated carbon.

(Functional Powder)
As the functional powder, sulfanilic acid (4-aminobenzenesulfonic acid) is preferred because of its superior reactivity with acidic gases and basic gases.

The average particle size (D50) of the functional powder is preferably 30 μm or less, and more preferably 20 μm or less. The lower limit of the average particle size (D50) of the functional powder is not particularly limited, and may be, for example, 5 μm or more.

The amount of functional powder used is preferably 5 to 30 parts by mass, and more preferably 10 to 20 parts by mass, per 100 parts by mass of activated carbon powder. When the amount of functional powder used is within the above range, it tends to be possible to obtain granulated carbon that has an even greater degree of removal performance due to chemical adsorption of the functional powder while maintaining the removal performance due to physical adsorption of the activated carbon.

(Water-based emulsion containing organic binder resin)
The aqueous emulsion containing an organic binder resin is used as a binder. The organic binder resin in the aqueous emulsion preferably has a glass transition temperature (Tg) of 0 to 200° C., more preferably 0 to 150° C., and even more preferably 0 to 120° C. In the present embodiment, even if the organic binder resin in the aqueous emulsion has a glass transition temperature in the above range, it is preferable to use an aqueous emulsion containing an organic binder resin that hardens at a temperature lower than the melting temperature of the functional powder.

Examples of organic binder resins include acrylic acid ester copolymers, ethylene-vinyl acetate copolymers, polyester resins, polycarbonate resins, polyamide resins, polyphenylene oxide resins, vinyl chloride resins, fluororesins, vinyl acetate resins, silicone resins, polyurethane resins, melamine resins, butyral resins, phenolic resins, unsaturated polyester resins, and acrylic resins, as well as copolymers and modified products of two or more of these resins. In this embodiment, resin also includes (co)polymers.

Preferred aqueous emulsions containing an organic binder resin include aqueous emulsions containing a self-crosslinking acrylic acid ester copolymer, aqueous emulsions containing a phenolic resin, and aqueous emulsions containing an ethylene-vinyl acetate copolymer, and more preferably aqueous emulsions containing an ethylene-vinyl acetate copolymer. The aqueous emulsions containing an ethylene-vinyl acetate copolymer preferably contain a solid content of about 40 to 60% by mass.

The average particle size (D50) of the organic binder resin is preferably 1 μm or less.

The amount of the aqueous emulsion containing the organic binder resin used is preferably 5 to 20 parts by mass, and more preferably 7 to 16 parts by mass, calculated as solid content per 100 parts by mass of the activated carbon powder. When the amount of the aqueous emulsion containing the organic binder resin is within the above range, the pores of the activated carbon powder tend not to be blocked further, and more suitable adsorption performance tends to be obtained. In addition, the hardness of the granulated carbon does not decrease, and clogging and damage tend not to occur when the granulated carbon is filled into containers, filters, etc.

(Other additives)
The granulated carbon may be obtained by kneading, granulating, sizing, and hardening a mixture of activated carbon powder, functional powder, an aqueous emulsion containing an organic binder resin, and, if necessary, metal oxides and other additives.
Such additives include, for example, lubricants.

Examples of lubricants include cacao butter, carboxymethylcellulose, methylcellulose, and heavy anhydrous silicic acid. Commercially available lubricants may also be used.

[Method of manufacturing granulated coal]
The method for producing granulated carbon of this embodiment includes a step of kneading activated carbon powder, a functional powder, an aqueous emulsion containing an organic binder resin, and, if necessary, a metal oxide, a step of granulating the kneaded product obtained in the kneading step, a step of sizing the granulated product obtained in the granulating step, and a step of hardening the sizing product obtained in the sizing step. In this embodiment, the sizing step is a step of sizing the granulated product using a spherical sizing machine.

The kneading process is, for example, a process in which the components are blended using a blender, a Henschel mixer, or the like. This process is usually carried out at room temperature, and the components are kneaded until they can be held by hand.

In the granulation process, for example, the kneaded material is extruded using an extrusion molding machine and then cut to obtain cylindrical granules.

In the sizing process, for example, the granulated material is sized into granulated charcoal having a predetermined shape using a spherical sizing machine. Through the sizing process, the corners of the granulated material are rounded off, and a granulated material having a cylindrical shape with an upper surface 1, a side surface 2, and a lower surface 3, and an edge 4 between the upper surface 1 and the side surface 2 and/or an edge 4 between the lower surface 3 and the side surface 2, is obtained. As an example of a spherical sizing machine, a Marmerizer (product name) manufactured by Dalton Co., Ltd. can be used.

In the hardening process, the granulated material is dried and hardened using, for example, a fluidized dryer to obtain granulated charcoal. The drying temperature may be any temperature at which the binder hardens but the functional powder does not melt, for example, about 50 to 150°C.

[Air purifier filters and air purifiers]
The air purifier filter of the present embodiment includes granulated charcoal. Also, the air purifier of the present embodiment includes granulated charcoal.

The granulated charcoal of this embodiment has sufficient adsorption performance for odorous gases such as ammonia gas, aldehyde gas, and acetic acid gas, has excellent hardness and abrasion resistance, and can be packed at a high packing density in air purifier filters. Therefore, it can be suitably used in air purifier filters and air purifiers. The shapes of the air purifier filters and air purifiers are not particularly limited, and the granulated charcoal can be used in air purifier filters and air purifiers, which are well-known industrial products.

The present invention will be described in detail below with examples and comparative examples, but the present invention is not limited to these examples in any way.

[Evaluation method]
(1) Specific surface area of activated carbon The specific surface area ( ^m2 /g) of activated carbon was measured based on the BET method using a specific surface area/pore distribution measuring device (BELSORP (registered trademark)-mini II (product name) manufactured by Microtrack-Bell).

(2) Average particle diameter (D50)
The average particle size (D50) was measured as a volume-based median size using a laser diffraction light scattering particle size distribution measuring device (MT3300EXII manufactured by Microtrac-Bell).

(3) Various Dimensions of Activated Carbon R ₁ , R ₂ , r, L, and D of the granulated carbon were measured using a vernier caliper and a scanning electron microscope.
The average value _R3 was calculated using _R1 and _R2 . In addition, _R3 /r (i.e., the average value of _R1 /r and _R2 /r) was calculated using _R3 .

(4) Hardness The hardness (%) of the granulated coal was measured in accordance with JIS K1474. Specifically, the granulated coal obtained by the method for measuring the packing density described below was used as the sample. The sample was placed in a hardness test dish together with 15 steel balls each having a diameter of 12.7 mm and a diameter of 9.5 mm, and was attached to a sieve shaker and shaken for 30 minutes. A sieve and a receiving dish with a sieve opening of 1.00 mm, which corresponds to two steps below the lower limit of the particle size indication range, were used, and all the sample except for the steel balls was placed in the sieve and the receiving dish, which were attached to the sieve shaker and shaken for 3 minutes. The mass (W) of the sample remaining on the sieve and the mass (S) of the sample remaining on the receiving dish were measured to the nearest 0.01 g, and calculated by the following formula.
Hardness (%) = W/(W+S) x 100

(5) Packing density of granulated coal The packing density (ρ, g/cm ³ ) of granulated coal was measured as follows. First, the granulated coal was dried in a thermostatic oven at 115±5°C for 3 hours and allowed to cool to room temperature in a desiccator. The granulated coal was then placed in a storage funnel. Using a vibrator, the granulated coal was filled up to the 100 mL mark in a packing density measurement container (100 mL graduated cylinder) set under the storage funnel so that the supply rate of the granulated coal was 0.75 to 1.0 mL/s. The granulated coal was removed from the packing density measurement container and its mass was measured to the nearest 0.01 g.

(6) Performance X
A deodorizing filter (opening size: 120 mm x 120 mm) filled with 30 g of granulated charcoal was attached to an air-cleaning fan or a small fan. This was stored in a ¹ m3 sealed container made of acrylic resin with a stirring fan and sealed. Then, five cigarettes (product name: Mebius) were burned using a cigarette smoker according to the JEMA1467 deodorizing performance test method. Five minutes after the cigarettes had finished burning, ammonia, acetaldehyde, and acetic acid were measured using gas detector tubes (Gastec No. 3La, No. 3L, No. 92L, and No. 81L (all detector tube names)) to obtain the initial gas concentrations. Then, the attached air-cleaning fan or small fan was operated for 30 minutes in (rapid) operation (air volume: about 1.1 ^m3 /min), and the gas concentrations after 30 minutes were measured using a gas detector tube in the same manner as above. The removal rate (%) of each of ammonia, acetaldehyde, and acetic acid was calculated from the initial gas concentration and the gas concentration after 30 minutes according to the following formula.
Initial removal rate (%)=(initial gas concentration−gas concentration after 30 minutes)/initial gas concentration×100
Thereafter, an average removal rate (%) was calculated from each removal rate (%), and this value was regarded as the initial removal rate (E, %) obtained by the JEMA1467 deodorizing performance test method.
Using this initial removal rate (E, %) and the packing density (ρ, g/cm ³ ), the performance X (%) shown in the above formula (1) was calculated.

Example 1
100 parts by mass of activated carbon powder (specific surface area: 1525 m ² /g, average particle size (D50): 25 μm) made from coconut shells was mixed with 14 parts by mass of sulfanilic acid (average particle size (D50): 9 μm) as a functional powder. 10 parts by mass (solid content 50-55% by mass, average particle size (D50): 0.7 μm) containing an ethylene-vinyl acetate copolymer as a binder (solid content 50-55% by mass, average particle size (D50): 0.7 μm) and 100 parts by mass of pure water were added to this mixture, and the mixture was kneaded for 3 minutes using a Henschel mixer to obtain a kneaded product. The kneaded product was then granulated using a molding die with a diameter of 2 mm in an extrusion molding machine to obtain cylindrical granulated products. The granulated product was then sized using a spherical granulator to obtain a sized product. The sized product was then dried using a fluidized bed dryer with hot air input temperature set to 100° C. and discharge temperature set to 80° C. to obtain granulated charcoal.
The obtained granulated coal was evaluated. The results are shown in Table 1.

Example 2
Except for carrying out simple granulation, pelletized coal was obtained in the same manner as in Example 1. The pelletized coal obtained was evaluated. The results are shown in Table 1.

Example 3
Except for carrying out simple granulation, pelletized coal was obtained in the same manner as in Example 1. The pelletized coal obtained was evaluated. The results are shown in Table 1.

Comparative Example 1
A pelletized coal was obtained in the same manner as in Example 1, except that the pellets were not sized. The pelletized coal obtained was evaluated. The results are shown in Table 1.

The results in Table 1 show that the granulated coal of Examples 1 to 3 have higher adsorption performance per volume than the granulated coal of Comparative Example 1.

Example 4
Pelletized charcoal was obtained in the same manner as in Example 1, except that activated carbon powder made from coconut shells (specific surface area: 1300 ^m2 /g, average particle size (D50): 22 μm) was used instead of activated carbon powder made from coconut shells (specific surface area: 1525 ^m2 /g, average particle size (D50): 25 μm). The obtained granulated charcoal was evaluated. The results are shown in Table 2.

Example 5
Pelletized charcoal was obtained in the same manner as in Example 1, except that activated carbon powder made from coconut shells (specific surface area: 1600 ^m2 /g, average particle size (D50): 27 μm) was used instead of activated carbon powder made from coconut shells (specific surface area: 1525 ^m2 /g, average particle size (D50): 25 μm). The obtained granulated charcoal was evaluated. The results are shown in Table 2.

Example 6
Pelletized charcoal was obtained in the same manner as in Example 1, except that activated carbon powder made from coconut shells (specific surface area: 1700 ^m2 /g, average particle size (D50): 26 μm) was used instead of activated carbon powder made from coconut shells (specific surface area: 1525 ^m2 /g, average particle size (D50): 25 μm). The obtained granulated charcoal was evaluated. The results are shown in Table 2.

Example 7
Pelletized coal was obtained in the same manner as in Example 5, except that 10 parts by mass of iron oxide (specific gravity: 5.24, average particle size (D50): 30 μm) was further added to the mixture as a metal oxide. The obtained granulated coal was evaluated. The results are shown in Table 3.

Example 8
Pelletized coal was obtained in the same manner as in Example 5, except that 10 parts by mass of copper oxide (specific gravity: 6.31, average particle size (D50): 27 μm) was further added to the mixture as a metal oxide. The obtained granulated coal was evaluated. The results are shown in Table 3.

Example 9
Pelletized coal was obtained in the same manner as in Example 5, except that 10 parts by mass of aluminum oxide (specific gravity: 3.95, average particle size (D50): 30 μm) was further added to the mixture as a metal oxide. The obtained granulated coal was evaluated. The results are shown in Table 3.

1...Top surface, 2...Side surface, 3...Bottom surface, 4...Edge (curved surface).

Claims (13)

a cylindrical shape having a top surface, a side surface, and a bottom surface;
an edge between the upper surface and the side surface and/or an edge between the lower surface and the side surface are curved surfaces;
The length of the curved surface of the edge portion in the radial direction of the upper surface is R ₁ ,
The length of the curved surface of the edge portion in the radial direction of the lower surface is _R2 ,
When the radius of the circular cross section having the largest area among the circular cross sections of the cylinder parallel to the radial direction of the upper surface is r,
the average value of R1 /r and R2 _/ r is 0.16 or more _and 0.69 or less;
where L is the length of a central axis of the cylinder and D is the diameter of a circular cross section of the cylinder parallel to the radial direction of the upper surface, the circular cross section having the largest area, and L/D is 1.7 or more and 3.0 or less,
Granulated coal having a hardness of 95% or more as measured in accordance with JIS K1474 . The granulated carbon according to claim 1 , wherein the performance X represented by the following formula (1) is 125 or more.
Performance X=(E/(30/ρ))×100...(1)
(In formula (1), E represents the initial removal rate (%) obtained by the JEMA 1467 deodorizing performance test method, and ρ represents the packing density (g/cm ³ ) of the granulated carbon). A step of kneading activated carbon powder, a functional powder, and an aqueous emulsion containing an organic binder resin;
A step of granulating the kneaded product obtained in the kneading step ;
A step of sizing the granulated product obtained in the granulation step ;
and hardening the sized product obtained in the sizing step .
The method for producing granulated charcoal according to claim 1 or 2 . The method for producing granulated carbon according to claim 3 , wherein the specific surface area of the activated carbon powder is less than 1400 m ² /g. A step of kneading an activated carbon powder, a functional powder, an aqueous emulsion containing an organic binder resin, and a metal oxide;
A step of granulating the kneaded product obtained in the kneading step ;
A step of sizing the granulated product obtained in the granulation step ;
and hardening the sized product obtained in the sizing step .
The specific surface area of the activated carbon powder is 1400 ^m2 /g or more.
The method for producing granulated charcoal according to claim 1 or 2 . The method for producing granulated charcoal according to claim 5 , wherein the specific gravity of the metal oxide is 2.5 or more. The method for producing granulated charcoal according to claim 5 or 6 , wherein the metal oxide is at least one selected from the group consisting of iron oxide, copper oxide, zinc oxide, and aluminum oxide. The method for producing granulated charcoal according to claim 3 , wherein the functional powder contains sulfanilic acid. The method for producing granulated charcoal according to any one of claims 3 to 8 , wherein the average particle size (D50) of the functional powder is 30 µm or less. The method for producing granulated charcoal according to any one of claims 3 to 9 , wherein the organic binder resin has an average particle size (D50) of 1 µm or less. A filter for an air purifier, comprising the granulated charcoal according to claim 1 or 2 . An air purifier comprising the granulated charcoal according to claim 1 or 2 . A step of kneading an activated carbon powder, a functional powder, an aqueous emulsion containing an organic binder resin, and, if necessary, a metal oxide;
A step of granulating the kneaded product obtained in the kneading step;
A step of sizing the granulated product obtained in the granulation step;
and hardening the sized product obtained in the sizing step.
The method for producing granulated charcoal according to claim 1 or 2 , wherein the sizing step is a step of sizing the granulated material using a spherical sizing machine.

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