JP2020093188A - Water purification filter - Google Patents

Abstract

To provide a thin water purification filter that can efficiently be produced and is excellent in handleability.SOLUTION: The water purification filter is a plate-shaped water purification filter of a thickness of 1 to 20 mm, comprising a molded body of activated carbon including fibrous activated carbon and granular activated carbon, and nonwoven fabric containing the molded body of the activated carbon therein, which nonwoven fabric is made from two pieces of nonwoven fabric bonded to each other at least at a position constituting the periphery of the water purification filter to contain the molded body of the activated carbon.SELECTED DRAWING: Figure 1

Description

The present invention relates to a water purification filter.

Conventionally, a thin water purification filter is known.

As a thin water purifying filter, water-permeable paper or non-woven fabric is used as a filter material, and an adsorbent material such as powder or granules of activated carbon is removed in the hollow part of the upper and lower filter layers where two pieces of this filter material are stacked, except for the adhering part of the filter material. A disposable water purification filter is known in which a layer is formed into a three-layer sheet of a filter medium, an adsorbent, and a filter medium, and the peripheral portions of both filter media, or a partition line portion provided as needed in addition to the peripheral portion is adhered. Has been.

Japanese Utility Model Publication No. 63-77689

When manufacturing the water purification filter disclosed in Patent Document 1, the following manufacturing method can be considered.
(1) A step of preparing powdered or granular activated carbon.
(2) A step of preparing a bag made of water-permeable paper or nonwoven fabric having an opening for inserting powdered or granular activated carbon.
(3) A step of inserting powdered or granular activated carbon from the opening of the bag.
(4) A step of closing the opening of the bag.
(5) Step of adhering the parting line portion if necessary

However, according to the study by the present inventor, it has been found that it is difficult to insert powdered or granular activated carbon from the opening of the bag body and the work efficiency is poor in the above manufacturing method. Further, the obtained water purification filter, even if provided with the demarcation line portion, uneven distribution occurs in the bag of the activated carbon of powder or granules, and due to this, there are a portion where the water to be purified easily flows and a portion which does not easily flow. We have learned that it is difficult to carry out efficient water purification and that handling is sometimes inferior.

Then, this invention solves the said problem, can manufacture a thin water purification filter efficiently, and makes it a main subject to provide the thin water purification filter which is excellent in handleability.

In order to solve the above problems, the present inventor first recalls that in the water filter of Patent Document 1, the adsorbent layer is a porous molded body obtained by solidifying powdered or granular activated carbon with a binder, a so-called carbon block. did. Then, specifically, slicing the columnar carbon block to a predetermined thin thickness, sandwiching the sliced carbon block with non-woven fabric from both sides, a position where the non-woven fabric on both sides becomes the peripheral portion of the water filter. We recalled the method of hot pressing and bonding, and we hoped that this could improve work efficiency and handleability.

However, when the present inventor performed the above method, when the carbon block is sliced, sandwiched with a non-woven fabric, or when carbon is molded into a board shape and punched to obtain a predetermined shape, carbon It has been found that cracks and chips may occur on the end faces of the blocks, making it difficult to efficiently produce water purification filters. Further, when sandwiching the sliced carbon block from both sides with a non-woven fabric and bonding the non-woven fabrics together by hot pressing at a position to be a peripheral portion of the water filter, the sliced carbon black is also cracked and chipped, resulting in a non-woven fabric. It was found that coal dust may easily leak out.

On the other hand, the present inventor uses a fibrous activated carbon as the activated carbon, an activated carbon fiber sheet that is wet paper-made to have a predetermined thickness, and prepares an activated carbon molded body that is punched into a predetermined shape from the surface direction, A method was also used in which this was sandwiched from both sides by a non-woven fabric, and the non-woven fabric on both sides was hot-pressed and bonded at a position to be a peripheral portion of the water filter. However, the present inventor has found that the water purifying filter obtained by the method is too soft and inferior in handleability in some cases, such as a bottle-type water purifier, and a small portable water purifier that can be carried. I learned that it may be difficult to attach a water purification filter to. Specifically, in order to prevent a short pass or the like of the water to be filtered, the water purification filter is fitted along the side surface of the water purification filter into a sealing material made of rubber or silicone resin (for example, a gasket, packing, etc.). May be attached by. However, it is difficult to fit the wet-paper-making activated carbon fiber sheet into a sealing material made of rubber or silicone resin, and it is difficult to mount it on a small portable water purifier or the like.

Therefore, the present inventor diligently studied, and the activated carbon molded body is molded in a state in which a activated carbon molded body containing fibrous activated carbon and granular activated carbon, or a sheet containing fibrous activated carbon is rolled, and the activated carbon molding is performed. By providing a body so that the longitudinal direction of the sheet is perpendicular to the thickness direction of the water purification filter, the hardness of the activated carbon molded body can be adjusted, and the activated carbon molded body It has been found that by adjusting the hardness of, it is possible to efficiently manufacture a thin water filter and to make it easy to handle. The present invention is an invention completed by earnest studies based on such findings.

That is, the present invention provides the inventions of the following modes.
Item 1. A flat water filter comprising an activated carbon molded body containing fibrous activated carbon and granular activated carbon, and a nonwoven fabric enclosing the activated carbon molded body, and having a thickness of 1 to 20 mm, wherein the nonwoven fabric is the purified water. A water purification filter that is joined to at least a part of the periphery of the filter and contains the activated carbon molded body.
Item 2. A flat water purification filter having an activated carbon molded body containing fibrous activated carbon and a non-woven fabric encapsulating the activated carbon molded body and having a thickness of 1 to 20 mm, wherein the activated carbon molded body is a fibrous activated carbon. The sheet containing is molded in a wound state, the activated carbon molded body, the longitudinal direction of the sheet is provided so as to be a direction perpendicular to the thickness direction of the water filter, the nonwoven fabric, A water purification filter which is joined to at least a part of a peripheral portion of the water purification filter and includes the activated carbon molded body.
Item 3. Item 3. The water purification filter according to Item 1 or 2, wherein the non-woven fabric is a non-woven fabric composed of continuous fibers.
Item 4. Item 4. The water purification filter according to Item 3, wherein the continuous fibers are partially pressure-bonded by hot embossing.
Item 5. Item 5. The water purification filter according to Item 3 or 4, wherein the continuous fiber is a core-sheath type composite fiber, and a melting point of a sheath part of the core-sheath type composite fiber is lower than a melting point of the core part.
Item 6. Item 6. The water filter according to any one of Items 1 to 5, wherein the density of the water filter is 0.1 to 0.5 g/cm ³ .

According to the water purification filter of the present invention, it is possible to efficiently manufacture a thin water purification filter, and it is also excellent in handleability. Therefore, it can be suitably used as a water purification filter for a small portable water purifier, such as a bottle type water purifier.

It is a typical sectional view explaining an example of the water purification filter of the present invention. It is a typical perspective view explaining an example of the activated carbon molding of the water purification filter of the present invention. It is a typical perspective view explaining an example of a form used when carrying out wet molding of the activated carbon molding of the water purification filter of the present invention.

The water purification filter according to the first embodiment of the present invention (hereinafter, may be abbreviated as “water purification filter of first embodiment”) is an activated carbon molded body containing fibrous activated carbon and granular activated carbon, and the activated carbon molded body. And a non-woven fabric containing the activated carbon molded body having a thickness of 1 to 20 mm and having a thickness of 1 to 20 mm, the non-woven fabric being joined at least at a part of a peripheral portion of the water purification filter. doing. Moreover, the water purification filter which concerns on 2nd Embodiment of this invention (Hereafter, it may abbreviate as "the water purification filter of 2nd Embodiment.") The activated carbon molded object containing fibrous activated carbon, and the said activated carbon molded object. A non-woven fabric to be included, which is a flat water filter having a thickness of 1 to 20 mm, wherein the activated carbon molded body is molded in a state in which a sheet containing fibrous activated carbon is wound, The activated carbon molded body is provided such that the longitudinal direction of the sheet is a direction perpendicular to the thickness direction of the water purification filter, and the non-woven fabric is bonded to at least a part of a peripheral portion of the water purification filter. Contains a molded body. Hereinafter, first, the activated carbon molded body included in the water purification filter of the first embodiment and the activated carbon molded body included in the water purification filter of the second embodiment will be described in detail.

<Activated carbon molded body included in the water purification filter of the first embodiment>
The activated carbon molded body included in the water purification filter of the first embodiment contains fibrous activated carbon and granular activated carbon. The water purification filter of the first embodiment is an activated carbon molded body containing fibrous activated carbon and granular activated carbon, whereby the hardness of the activated carbon molded body can be adjusted, whereby a thin water purification filter can be efficiently formed. It can be manufactured and can be easily handled.

In the activated carbon molded body included in the water purification filter of the first embodiment, the specific surface area of the fibrous activated carbon is not particularly limited, but examples thereof include 700 to 3000 m ² /g, and the strength of the thin water purification filter. From the viewpoint of making the performance of removing free residual chlorine more compatible, 700 to 1500 m ² /g is preferably mentioned. In the present invention, the specific surface area is a value measured by the BET method (one-point method) using nitrogen as the substance to be adsorbed. The average fiber diameter of the fibrous activated carbon is not particularly limited, but examples thereof include 5 to 30 μm. The average fiber diameter of the fibrous activated carbon is measured and calculated by a reflection microscope according to JIS K 1477:2007 73.1.

In the activated carbon molded body included in the water purification filter of the first embodiment, the fibrous activated carbon may be silver-supported fibrous activated carbon from the viewpoint of imparting antibacterial performance to the water purification filter.

In the activated carbon molded body included in the water purification filter of the first embodiment, the specific surface area of the granular activated carbon is not particularly limited, but examples thereof include 700 to 3000 m ² /g, and the upper and lower surfaces in the thickness direction of the activated carbon molded body. 800 to 2000 m ² /g is more preferable from the viewpoint of making both the average value of the hardness of No. 1 and the average value of the hardness of the side surface of the activated carbon molded body higher and the removal performance of free residual chlorine more compatible. Be done. Moreover, 20-500 micrometers is mentioned as an average particle diameter of granular activated carbon. The average particle size of the granular activated carbon is 50% as the cumulative volume value in the particle size distribution of the granular activated carbon measured using a laser diffraction/scattering type particle size distribution measuring device (trade name LA-920 manufactured by Horiba Ltd.). Is the grain size.

In the activated carbon molded body included in the water purification filter of the first embodiment, the granular activated carbon may be silver-loaded granular activated carbon from the viewpoint of imparting antibacterial performance to the water purification filter.

In the activated carbon molded body included in the water purification filter of the first embodiment, the content ratio of the fibrous activated carbon in the activated carbon molded body is, for example, 15 to 60% by mass, and more preferably 25 to 50% by mass. The content ratio of the granular activated carbon is, for example, 40 to 85% by mass, and preferably 50 to 75% by mass. Further, in the activated carbon molded body, the mass ratio of the activated carbon (fibrous activated carbon and granular activated carbon) is 70% by mass or more, and preferably 80% by mass or more. The upper limit of the mass ratio is not particularly limited, but is, for example, 95 mass% or less, and preferably 90 mass% or less. In the activated carbon molded body included in the water purification filter of the first embodiment, the mass ratio of the fibrous activated carbon and the granular activated carbon (granular activated carbon/fibrous activated carbon) is, for example, 0.1 to 10, and preferably 1 to 5. Can be mentioned.

The activated carbon molded body included in the water purification filter of the first embodiment can include other components other than the fibrous activated carbon and the granular activated carbon. Examples of the other component include one or more lead removing components selected from the group consisting of ion exchange fibers, ion exchange resins, chelate fibers, chelate resins, titanium silicate and zeolite. When the lead removal component is contained in the activated carbon molded body, the content ratio thereof is, for example, 1 to 20% by mass, preferably 2 to 10% by mass.

Moreover, pulp is mentioned as said other component. By containing pulp, the strength of the activated carbon molded body can be further increased, cracks and chips of the activated carbon molded body can be further reduced, and the handleability of the water purification filter can be further improved. Specific examples of the pulp include cellulose pulp, acrylic pulp, polyethylene pulp and the like. Above all, it is preferable that the melting point of the pulp is higher than the fusion component of the nonwoven fabric containing the activated carbon molded body, which will be described later. As a result, in a step of covering the activated carbon molded body with the nonwoven fabric from both sides in the thickness direction, which will be described later, the nonwoven fabric is bonded at a position to be a peripheral portion of the water filter, and the activated carbon molded body is encapsulated with the nonwoven fabric. When heat-sealing, the pulp does not melt in the activated carbon molded body, and it is possible to easily maintain the pore structure of the activated carbon such as fibrous activated carbon. The preferable melting point of the pulp is, for example, 10° C. or higher than the fusion component of the nonwoven fabric containing the activated carbon molded body, and for example, the melting point is 130° C. or higher, preferably 150° C. or higher, more preferably 200° C. or higher. Is mentioned. In addition, in this invention, when it does not have a melting point, let a softening point be a melting point. Further, in the present invention, the melting point is defined as a temperature which gives an extreme value of a melting absorption curve measured by a differential scanning calorimeter (DSC7 manufactured by Perkin Elmer Co., Ltd.) at a temperature rising rate of 20° C./min. When pulp is contained in the activated carbon molded body, the content ratio thereof is, for example, 1 to 15% by mass, and preferably 3 to 12% by mass.

In addition, the activated carbon molded body included in the water purification filter of the first embodiment can include a synthetic resin component having a melting point of 150°C or lower, preferably 120°C or lower, as the other component. Above all, it is preferable to include a core-sheath type composite fiber as the other component, and to include a synthetic resin component having a melting point of 150° C. or lower, preferably 120° C. or lower, as a sheath component of the core-sheath type composite fiber. On the other hand, the activated carbon molded body may not contain a synthetic resin component other than the lead removing component.

The average value of the hardness of the upper surface and the lower surface in the thickness direction of the activated carbon molded body included in the water purification filter of the first embodiment is from the viewpoint of making cracks and cracks in the activated carbon molded body less and improving the handleability. , 30 to 70 are preferable, and 40 to 70 are more preferable. Further, the average value of the hardness of the side surface of the activated carbon molded body is preferably 30 to 70, and more preferably 40 to 70, from the viewpoint of making cracking and chipping of the activated carbon molded body more compatible with improving handleability. ..

In the present invention, the hardness is based on JIS S 6050, and a durometer model GS-701N manufactured by Teclock Co., Ltd. is used. As the hardness of the upper surface and the lower surface in the thickness direction of the activated carbon molded body, the activated carbon molded body is hollow. It is placed in the middle of the pedestal, the center of the upper surface is measured at three points, and the median value is read. As the hardness of the side surface of the activated carbon molded body, the side surface is measured at three points and the median value is read.

The thickness of the activated carbon molded body included in the water purification filter of the first embodiment is 1 to 20 mm, and preferably 1 to 10 mm. The volume of the activated carbon molded body is ³ to 30 cm ³ , and preferably 5 to 20 cm ³ . The mass of the activated carbon molded product is preferably 0.1 to 10 g, more preferably 1 to 5 g. The density of the activated carbon molded body is preferably 0.2 to 0.5 g/cm ^{3, and} more preferably 0.3 to 0, from the viewpoint of making cracking and chipping of the activated carbon molded body more compatible with improving the handleability. More preferably, it is 0.5 g/cm ³ .

The form of the activated carbon molded body included in the water purification filter of the first embodiment is not particularly limited, but examples thereof include the following.
(1) A slurry containing fibrous activated carbon and granular activated carbon is prepared, and the slurry is poured into, for example, a molding frame 5 having a large number of suction small holes 6 shown in FIG. The activated carbon molded product (hereinafter, abbreviated as "slurry suction molded product") manufactured by a method (wet molding method or slurry suction method) in which the preformed product is filtered by suction through is there.). In this case, the obtained activated carbon molded article may be one in which the fibrous activated carbon and the granular activated carbon are entangled with each other by the pulp described above and the shape thereof is maintained.
(2) A non-woven fabric containing fibrous activated carbon and granular activated carbon. Examples of the form of the non-woven fabric include dry non-woven fabric and wet non-woven fabric. Examples of the dry non-woven fabric include a non-woven fabric having a short fiber structure obtained by an air-laid or card method (card web method), and a needle-punched non-woven fabric obtained by subjecting the non-woven fabric to needle-punching and lamination and integration. As the wet non-woven fabric, a solution containing a fibrous carbon material is mixed and sheared using a device such as pulper, beater, and refiner to prepare a uniformly dispersed slurry, and the obtained slurry is poured onto a wire and dehydrated. A wet papermaking non-woven fabric obtained by drying. In the case of a dry non-woven fabric, the granular activated carbon can be contained by a known method. For example, a method of preparing two dry non-woven fabrics and sandwiching the granular activated carbon between the two dry non-woven fabrics can be mentioned.

<Activated carbon molded body included in the water purification filter of the second embodiment>
The activated carbon molded body included in the water purification filter of the second embodiment contains fibrous activated carbon, and the activated carbon molded body is molded in a state in which a sheet containing fibrous activated carbon is wound, and the activated carbon molded body is The longitudinal direction of the sheet is provided so as to be perpendicular to the thickness direction of the water purification filter.

FIG. 2 is a schematic perspective view illustrating an example of an activated carbon molded body included in the water purification filter of the second embodiment, which is molded in a state in which a sheet containing fibrous activated carbon is wound. In FIG. 2, the activated carbon molded body 2 is molded in a state in which a sheet 23 containing fibrous activated carbon is wound in a spiral shape. It is arranged so as to be perpendicular to the depth direction. In FIG. 2, in the activated carbon molded body 2, the front surface or the back surface of the sheet 23 forms the side surface 21 of the activated carbon molded body 2, and the longitudinal end portions (ears) of the sheet 23 are arranged in a spiral shape and the upper surface of the activated carbon molded body 2. 22 and a lower surface (not shown) are formed. In the activated carbon molded body shown in FIG. 2, the direction from the upper surface 22 to the lower surface and the direction from the lower surface to the upper surface 22 are the thickness directions of the activated carbon molded body. Water to be purified is preferably passed in the thickness direction of the activated carbon molded body 2. Further, as shown in FIG. 2, it is preferable that the activated carbon molded body 2 does not have a hollow portion that communicates in the thickness direction and a core made of another member. In this way, by forming the upper surface 22 and the lower surface of the activated carbon molded body 2 by arranging a plurality of longitudinal end portions of the sheet 23 side by side, the hardness of the upper surface 22 and the lower surface can be adjusted. Further, by winding the sheet 23 under tension, the activated carbon molded body 2 is compressed in the direction from the side surface 21 toward the center, and the hardness of the side surface 21 can be adjusted. As a method for producing the activated carbon molded body, a sheet 23 containing fibrous activated carbon is prepared, and the sheet 23 is wound around a thin core made of resin, the core is removed, and then the core is removed. The hollow portion formed is crushed to manufacture the sheet core. Then, a sheet 23 containing fibrous activated carbon is again wound around the obtained core made of the sheet by applying tension, and the form is fixed by heat treatment or the like, and the activated carbon molded body 2 has a predetermined thickness if necessary. The method of cutting into the activated carbon molded body 2 by cutting in the plane direction perpendicular to the thickness direction so that In addition, the sheet may contain other components other than the granular activated carbon and/or the fibrous activated carbon and the granular activated carbon described in the section of the activated carbon molded body included in the water purification filter of the first embodiment.

The form of the sheet 23 containing the fibrous activated carbon is preferably a non-woven fabric. Examples of the non-woven fabric include dry non-woven fabric and wet non-woven fabric. Examples of the dry non-woven fabric include a non-woven fabric having a short fiber structure obtained by an air-laid or card method (card web method), and a needle-punched non-woven fabric obtained by subjecting the non-woven fabric to needle-punching and lamination and integration. As the wet non-woven fabric, a solution containing a fibrous carbon material is mixed and sheared using a device such as pulper, beater, and refiner to prepare a uniformly dispersed slurry, and the obtained slurry is poured onto a wire and dehydrated. A wet papermaking non-woven fabric obtained by drying. More specifically, the sheet is a non-woven fabric containing fibrous activated carbon, and the fibrous activated carbon is in a state in which the pulp is intertwined with each other to maintain a shape, and/or a synthetic resin component described below is used to separate the fibrous activated carbon from each other. It may be mentioned that it is melt-bonded to maintain its shape.

In the activated carbon molded body included in the water purification filter of the second embodiment, the specific surface area of the fibrous activated carbon is not particularly limited, but examples thereof include 700 to 3000 m ² /g, and the strength of the thin water purification filter. From the viewpoint of making the performance of removing free residual chlorine more compatible, 700 to 1500 m ² /g is preferably mentioned. The average fiber diameter of the fibrous activated carbon is not particularly limited, but examples thereof include 5 to 30 μm.

In the activated carbon molded body included in the water purification filter of the second embodiment, the fibrous activated carbon may be silver-supported fibrous activated carbon from the viewpoint of imparting antibacterial performance to the water purification filter.

The activated carbon molded body included in the water purification filter of the second embodiment can include granular activated carbon. The specific surface area of the granular activated carbon is not particularly limited, but examples thereof include 700 to 3000 m ² /g, the average value of the hardness of the upper surface and the lower surface of the activated carbon molded body in the thickness direction, and the hardness of the side surface of the activated carbon molded body. 800 to 2000 m ² /g is more preferable from the viewpoint of making both the average value of and the removal performance of free residual chlorine more compatible. Moreover, 20-500 micrometers is mentioned as an average particle diameter of granular activated carbon. The granular activated carbon may be silver-loaded granular activated carbon from the viewpoint of imparting antibacterial performance to the water purification filter. In addition, the activated carbon molded body included in the water purification filter of the second embodiment may not include granular activated carbon.

The activated carbon molded body included in the water purification filter of the second embodiment can include other components other than the fibrous activated carbon and the granular activated carbon. Examples of the other component include one or more lead removing components selected from the group consisting of ion exchange fibers, ion exchange resins, chelate fibers, chelate resins, titanium silicate and zeolite. When the lead removal component is contained in the activated carbon molded body, the content ratio thereof is, for example, 1 to 20% by mass, preferably 2 to 10% by mass.

Moreover, pulp is mentioned as said other component. By containing pulp, the strength of the activated carbon molded body can be further increased, cracks and chips of the activated carbon molded body can be further reduced, and the handleability of the water purification filter can be further improved. Specific examples of the pulp include cellulose pulp, acrylic pulp, polyethylene pulp and the like. Above all, it is preferable that the melting point of the pulp is higher than the fusion component of the nonwoven fabric containing the activated carbon molded body, which will be described later. The preferable melting point of the pulp is, for example, 10° C. or higher than the fusion component of the nonwoven fabric containing the activated carbon molded body, and for example, the melting point is 130° C. or higher, preferably 150° C. or higher, more preferably 200° C. or higher. Is mentioned. In addition, in this invention, when it does not have a melting point, let a softening point be a melting point. Further, in the present invention, the melting point is defined as a temperature which gives an extreme value of a melting absorption curve measured with a differential scanning calorimeter (DSC7 manufactured by Perkin Elmer Co., Ltd.) at a heating rate of 20° C./min. When pulp is contained in the activated carbon molded body, the content ratio thereof is, for example, 1 to 15% by mass, preferably 1 to 8% by mass.

In addition, the activated carbon molded body included in the water purification filter of the second embodiment may include a synthetic resin component having a melting point of 150°C or lower, preferably 120°C or lower, as the other component. Among them, the core is composed of a synthetic resin component having a melting point of 150° C. or less, preferably 120° C. or less, and the core part is composed of a synthetic resin having a melting point of 30° C. or more higher than that of the synthetic resin component forming the sheath part. Preferable is a sheath type fiber. When a fiber having a synthetic resin component having a melting point of 150° C. or lower, preferably 120° C. or lower is included, the content of the fiber in the activated carbon molded body included in the water purification filter of the second embodiment is 5 to 30% by mass. And 8 to 25 mass% is more preferable.

As the average hardness of the upper surface and the lower surface in the thickness direction of the activated carbon molded body included in the water purification filter of the second embodiment, from the viewpoint of making the activated carbon molded body less susceptible to cracking and chipping and improving handleability. , 30 to 70 are preferable, and 40 to 70 are more preferable. Further, the average value of the hardness of the side surface of the activated carbon molded body is preferably 30 to 70, and more preferably 40 to 70, from the viewpoint of making cracking and chipping of the activated carbon molded body more compatible with improving handleability. ..

The thickness of the activated carbon molded body included in the water purification filter of the second embodiment is 1 to 20 mm, and preferably 1 to 10 mm. The volume of the activated carbon molded body is ³ to 30 cm ³ , and preferably 5 to 20 cm ³ . The mass of the activated carbon molded product is preferably 0.1 to 10 g, more preferably 1 to 5 g. The density of the activated carbon molded product is preferably 0.1 to 0.4 g/cm ^{3, and} more preferably 0.1 to 0.0, from the viewpoint of making cracking and chipping of the activated carbon molded product more compatible with improving handleability. 25 g/cm ³ is more preferable.

<Nonwoven fabric>
Next, the non-woven fabric that the water purification filter of the first embodiment and the water purification filter of the second embodiment have in common will be described in detail. In the water purifying filter of the first embodiment and the water purifying filter of the second embodiment, the non-woven fabric is joined at least at a part of the peripheral portion of the water purifying filter and includes the activated carbon molded body. By including the activated carbon molded body with a non-woven fabric, it is possible to prevent the carbon dust generated from the activated carbon molded body from leaking to the outside of the water purification filter.

In the water purifying filter of the first embodiment and the water purifying filter of the second embodiment, the form of the non-woven fabric containing the activated carbon molded body is not particularly limited. Among them, a nonwoven fabric composed of continuous fibers is preferable from the viewpoint of excellent mechanical strength while making it easier to prevent wrinkles from occurring in the manufacturing process. Examples of the non-woven fabric composed of continuous fibers include spun-bonded non-woven fabric, melt blown non-woven fabric and flash spun non-woven fabric, and among them, spun-bonded non-woven fabric is preferable. Further, the non-woven fabric composed of continuous fibers can be integrated by partially pressing the deposited continuous fibers together by hot embossing. As a result, the occurrence of the wrinkles can be further reduced.

Examples of the continuous fiber include inorganic fibers such as carbon fiber, glass fiber, ceramic fiber, aramid fiber, vinylon fiber, polypropylene fiber, polyethylene fiber, polyarylate fiber, polybenzoxazole (PBO) fiber, polyphenylene sulfide fiber, nylon fiber, polyester. Examples thereof include fibers, wholly aromatic polyester fibers, acrylic fibers, vinyl chloride fibers, polyketone fibers, cellulose fibers, and organic fibers such as pulp fibers.

It is particularly preferable that the continuous fiber is a core-sheath type composite fiber composed of a core portion and a sheath portion, the melting point of the sheath portion being lower than that of the core portion. By using the core-sheath type composite fiber as the continuous fiber, only the sheath portion can be appropriately melted, and the adhesiveness of the nonwoven fabric is improved. Furthermore, since the sheath is melted while leaving the core, it is possible to maintain the fiber shape as much as possible and easily maintain the mechanical strength of the nonwoven fabric.

The core-sheath type composite fiber is not particularly limited, but may be one having a melting point of the sheath portion lower than that of the core portion by 30° C. or more. For example, a core-sheath type composite fiber in which the core has a melting point of 150 to 280° C., the sheath has a melting point of 80 to 160° C., and the sheath has a melting point lower than the melting point of the core by 30° C. or more. Can be mentioned. Examples of the combination of the core portion and the sheath portion include a combination in which the core portion is polyethylene terephthalate or polypropylene and the sheath portion is a copolyester having a melting point of 160° C. or lower, polyethylene or polypropylene. More specifically, a core-sheath composite in which the core is polypropylene having a melting point of 150 to 180° C. and the sheath is polyethylene having a melting point of 100 to 140° C. (preferably a high density polyethylene having a density of 0.942 g/cm ³ or more). A fiber, a core-sheath type composite fiber in which the core portion is polyethylene terephthalate having a melting point of 230 to 280° C., and the sheath portion is polyethylene having a melting point of 110 to 150° C. (preferably a high-density polyethylene having a density of 0.942 g/cm ³ or more), or Examples thereof include polyethylene terephthalate having a melting point of 230 to 280° C. in the core, and copolyester having a melting point of 30° C. or more lower than that of the core in the sheath (preferably copolymerized polyethylene terephthalate copolymerized with isophthalic acid).

The single yarn fineness of the continuous fiber is not particularly limited, but is, for example, 1 to 20 dtex, and more preferably 1 to 10 dtex.

In the water purifying filter of the first embodiment and the water purifying filter of the second embodiment, the mass (g/m ² ) of the non-woven fabric containing the activated carbon molded body makes it easier to prevent wrinkles from occurring in the non-woven fabric, while depending on the formability. From the viewpoint of being excellent, 15 to 100 g/m ² is preferable, and 30 to 60 g/m ² is more preferable. Moreover, in the water filter of the first embodiment and the water filter of the second embodiment, the thickness of the nonwoven fabric containing the activated carbon molded body is more excellent in moldability while making it easier to prevent wrinkles from occurring in the nonwoven fabric. From the viewpoint of, 0.1 to 0.6 mm is preferable, and 0.1 to 0.4 mm is more preferable.

In the water purification filter of the first embodiment and the water purification filter of the second embodiment, the tensile strength (N/5 cm) of the nonwoven fabric is 10 to 800 N/25 mm in the MD direction (machine direction), and the CD direction (method orthogonal to the MD direction). ) Is 5 to 500 N/25 mm. The ratio of the tensile strength in the MD direction to the tensile strength in the CD direction (MD direction/CD direction) is 1.2 to 3.0, and preferably 1.5 to 2.5. In addition, the tensile strength in the MD direction is preferably 100 to 300 N/5 cm, and the tensile strength in the CD direction is preferably 50 to 200 N/5 cm from the viewpoint of making it more excellent in moldability while making it easier to prevent the generation of wrinkles in the nonwoven fabric. .. In the present invention, the tensile strength of the nonwoven fabric is measured and calculated as follows. That is, according to JIS L 1913:2010 6.3, using a Tensilon RTM-500 type manufactured by Toyo Baldwin Co., Ltd., a test piece having a width of 50 mm and a length of 200 mm was measured under the conditions of a gripping interval of 100 mm and a pulling speed of 100 mm/min. Then, the average value of 10 points of the sample is obtained and the tensile strength is obtained.

In the water purification filter of the first embodiment and the water purification filter of the second embodiment, when the activated carbon molded body is covered with the above-mentioned nonwoven fabric from both sides in the thickness direction, one nonwoven fabric may be folded and covered. You may cover using the non-woven fabric of.

In the present invention, the non-woven fabric containing the activated carbon molded body may be formed by previously forming a recessed portion that matches the shape of the activated carbon molded body. Specifically, for example, a mold having a core and a cavity having substantially the same shape as the activated carbon molded body is heated to a temperature at which thermoforming is possible, and the non-woven fabric is set between the core and the cavity. Examples include thermoforming a non-woven fabric with a mold. Then, the activated carbon molded body having a predetermined shape is set in the molded hollow portion of the nonwoven fabric, and the activated carbon molded body has a planar shape so as to include the activated carbon molded body from the side opposite to the side where the molded nonwoven fabric is arranged. A non-woven fabric can be placed to cover the activated carbon molding. By doing so, the activated carbon molded body can be included as much as possible without excess extra nonwoven fabric, and it is possible to easily prevent wrinkles from occurring in the non-woven fabric.

<Water purification filter>
In the water purification filter of the first embodiment and the water purification filter of the second embodiment, the above-mentioned non-woven fabric is joined at least at a part of the peripheral portion of the water purification filter of the first embodiment described above or the water purification filter of the second embodiment. It contains activated carbon molding.

As shown in FIG. 1, the water purification filter 1 of the present invention includes an activated carbon molded body 2 containing fibrous activated carbon and a nonwoven fabric 3 encapsulating the activated carbon molded body, and has a thickness of 1 to 20 mm. Then, the non-woven fabric 3 is joined to at least a part of the peripheral portion 4 of the water purification filter 1, preferably all, and encloses the activated carbon molded body 2. The plane shape of the water purification filter is not particularly limited, and examples thereof include a circle, an ellipse, a rectangle, a triangle, and a crescent shape.

The joining method is not particularly limited, but with a heat press having a tubular mold having substantially the same shape as the peripheral portion of the water purifying filter 1, the mold is attached to the peripheral portion 4 from above one of the nonwoven fabrics 3. Preferred is a method in which the upper non-woven fabric 3 and the lower non-woven fabric 3 are heat-sealed at the peripheral edge portion 4 by hot pressing at different positions. In addition, it is also possible to prepare two planar nonwoven fabrics 3, arrange the activated carbon molded bodies 2 from above and below to cover the activated carbon molded bodies 2 so as to sandwich the activated carbon molded bodies 2, and perform the hot pressing from one of the nonwoven fabrics 3.

As the preferable water purification performance of the water purification filter of the present invention, in accordance with JIS S 3201:2017, the removal rate is 80% or less in the free residual chlorine filtration capacity test measured at a filtration flow rate of 0.1 L/min. It is preferable that the total amount of filtered water until it becomes 200 L or more, and more preferably 250 L or more.

As the preferable water purification performance of the water purification filter of the present invention, according to JIS S 3201:2017, in the filtration performance test of 2-MIB measured at a filtration flow rate of 0.1 L/min, the removal rate is 80% or less. It is preferable that the total amount of filtered water until it becomes 100 L or more, and more preferably 150 L or more.

As the preferable water purification performance of the water purification filter of the present invention, in accordance with JIS S 3201:2017, in a soluble lead filtration capacity test measured at a filtration flow rate of 0.1 L/min, the removal rate is 80% or less. It is preferable that the total amount of filtered water until it becomes 100 L or more, and more preferably 150 L or more.

<Method for producing water purification filter of the present invention>
Next, a method for manufacturing the water purification filter of the present invention will be described.

The method for producing a water purification filter of the present invention is a method for producing a flat water purification filter having an activated carbon molded body and a nonwoven fabric containing the activated carbon molded body from both sides in the thickness direction and having a thickness of 1 to 20 mm. That is, the step A of preparing the activated carbon molded body included in the water purification filter of the first embodiment described above or the activated carbon molded body included in the water purification filter of the second embodiment described above, and the activated carbon molded body on both sides in the thickness direction. From the step B of covering with the non-woven fabric, and in a state where the activated carbon molded body is covered with the non-woven fabric from both sides in the thickness direction, the non-woven fabric is joined at a position to be a peripheral portion of the water filter, and the non-woven fabric is used to form the activated carbon. Step C of including the body. Further, the production method of the present invention may include a step of cutting the prepared activated carbon molded body into a predetermined shape, following the step (A).

As described above, in the method for producing a water purification filter of the present invention, prior to the step (B), a non-woven fabric containing an activated carbon molded body may be formed with a recessed portion that matches the shape of the activated carbon molded body. preferable. Specifically, for example, a mold having a core and a cavity having substantially the same shape as the activated carbon molded body is heated to a temperature at which thermoforming is possible, and the non-woven fabric is set between the core and the cavity. Examples include thermoforming a non-woven fabric with a mold. Then, the activated carbon molded body having a predetermined shape is set in the formed hollow portion of the nonwoven fabric, and the nonwoven fabric is arranged so as to enclose the activated carbon molded body from the side opposite to the side where the molded nonwoven fabric is arranged in the activated carbon molded body. Then, the activated carbon molded body can be covered. By doing so, the activated carbon molded body can be included as much as possible without excess extra nonwoven fabric, and it is possible to easily prevent wrinkles from occurring in the non-woven fabric.

The method for producing a water purification filter of the present invention can optionally include a nonwoven fabric cutting step of cutting a nonwoven fabric containing an activated carbon molded body into a shape along the peripheral portion of the water purification filter. The order of the non-woven fabric cutting step and the steps A to C is not particularly limited. Before the step A, before the step B, or before the step C, a non-woven fabric cutting step may be provided in advance or after the step C. Further, before the step C, a step of preparing a non-woven fabric cut into a shape along the peripheral portion of the water purification filter may be provided.

<Use of water filter>
Since the water purification filter of the present invention is thin, for example, it is suitable for a small portable water purifier such as a pot type water purifier, a bottle type, a tumbler type, a straw type, and a bag type. As a bottle type water purifier, specifically, a water storage unit for storing raw water to be filtered, and a water purification filter of the present invention which is detachably provided above the water storage unit and which filters the raw water stored in the water storage unit. A bottle-type water purifier, comprising: a suction port portion that is detachably provided above the water purification filter and has a through hole through which raw water filtered by passing through the water purification filter passes. Type water purifier, raw water is stored in the water storage section by removing the water purification filter and the mouthpiece, after storing raw water in the water storage section, the water purification filter and the mouthpiece are set in the water storage section, A bottle-type water purifier in which the raw water is filtered by passing through the water purification filter when the user drinks it, and is used for drinking through the mouthpiece part is mentioned.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

(Example 1)
1. Step A of preparing activated carbon molded body
15 parts by mass of coal pitch-based activated carbon fiber A (specific surface area 1070 m ² /g, fiber diameter 16 μm) as fibrous activated carbon, and coconut shell activated carbon F (specific surface area 1000 m ² /g, average particle diameter 220 μm) as granular activated carbon 70 5 parts by mass of Unitika Co., Ltd. product name “A-02CA” as ion exchange fiber, 10 parts by mass of Japan Exlan Industrial Co., Ltd. product name “Bi-PUL” as acrylic pulp, totaling 100 parts by mass. , A slurry is prepared by dispersing in water, poured into a circular molding frame 5 having a large number of suction small holes 6 as illustrated in FIG. The formed body was dried, and the preformed body was dried to obtain an activated carbon molded body which was a slurry suction molded body. The obtained activated carbon molded body was disk-shaped, the outer diameter was 54.3 mm, the thickness was 4.3 mm, the mass was 2.59 g, and the hardness of the upper and lower surfaces in the thickness direction of the activated carbon molded body was 46, activated carbon. The hardness of the side surface of the molded body was 62.

2. Preparation of non-woven fabric containing activated carbon molding A non-woven fabric containing activated carbon molding is a spunbond non-woven fabric consisting of continuous fibers, which is a core-sheath type composite fiber whose core part is made of polyester resin and whose sheath part is made of polyolefin resin. There is a nonwoven fabric in which the continuous fibers that have been deposited are integrated by being partially pressure-bonded by hot embossing, manufactured by Unitika Ltd. under the trade name Elves (registered trademark) S0503WDO (mass 50 g/m ² , thickness). 0.34 mm, MD tensile strength of 215 N/25 mm, CD tensile strength of 100 N/25 mm) were prepared. A mold having a core and a cavity having substantially the same shape as the obtained activated carbon molded body was heated to a temperature of 120° C., and one of the above two nonwoven fabrics was set between the core and the cavity. The non-woven fabric was thermoformed to form a depression having the same shape as the activated carbon molding.

3. Step B of covering the activated carbon molded body with a non-woven fabric from both sides in the thickness direction
The activated carbon molded body is set in the hollow portion of the thermoformed nonwoven fabric, and another nonwoven fabric is included so as to enclose the activated carbon molded body from the side opposite to the side where the thermoformed nonwoven fabric is arranged as seen from the activated carbon molded body. Was placed, and the entire activated carbon molded body was covered with two non-woven fabrics.

4. Process C in which the activated carbon molded body is covered with the nonwoven fabric from both sides in the thickness direction, the nonwoven fabric is bonded at a position which becomes the peripheral portion of the water purification filter, and the activated carbon molded body is included in the nonwoven fabric.
From the thermoformed non-woven fabric side, a die is heat-pressed at a temperature of 240° C. at a position which becomes the above-mentioned peripheral portion 4 with a heat press having a cylindrical mold having substantially the same shape as the peripheral portion of the water purifying filter, and the upper heat The formed non-woven fabric and the lower non-woven fabric were heat-sealed at the peripheral edge to enclose the activated carbon molded body. Then, the two non-woven fabrics were cut into a circle so that the width of the peripheral portion was 1 to 2 mm, and the water purification filter of Example 1 was obtained.

(Example 2)
15 parts by mass of coal pitch-based activated carbon fiber A (specific surface area 1070 m ² /g, fiber diameter 16 μm) as fibrous activated carbon, and coconut shell activated carbon G (specific surface area 1700 m ² /g, average particle diameter 420 μm) as granular activated carbon 70 5 parts by mass of Unitika Co., Ltd. product name A-02CA as ion exchange fiber, 10 parts by mass of Japan Exlan Industrial Co., Ltd. product name Bi-PUL as acrylic pulp, 100 parts by mass in total are dispersed. To prepare a slurry, pour it into a circular molding frame 5 having a large number of suction small holes 6 as illustrated in FIG. 3, and filter while sucking through the suction small holes 6 to obtain a preform. The preformed body was dried to obtain an activated carbon molded body which was a slurry suction molded body. The obtained activated carbon molded body was disc-shaped, had an outer diameter of 46.3 mm, a thickness of 4.3 mm, a mass of 1.74 g, a hardness of the upper and lower surfaces in the thickness direction of the activated carbon molded body of 65, and activated carbon. The hardness of the side surface of the molded body was 64.

2. Preparation of non-woven fabric containing activated carbon molding A non-woven fabric containing activated carbon molding is a spunbond non-woven fabric consisting of continuous fibers, which is a core-sheath type composite fiber whose core part is made of polyester resin and whose sheath part is made of polyolefin resin. There is a nonwoven fabric in which the continuous fibers that have been deposited are integrated by being partially pressure-bonded by hot embossing, manufactured by Unitika Ltd. under the trade name Elves (registered trademark) S0503WDO (mass 50 g/m ² , thickness). 0.34 mm, MD tensile strength of 215 N/25 mm, CD tensile strength of 100 N/25 mm) were prepared. A mold having a core and a cavity having substantially the same shape as the obtained activated carbon molded body was heated to a temperature of 120° C., and one of the above two nonwoven fabrics was set between the core and the cavity. The non-woven fabric was thermoformed to form a depression having the same shape as the activated carbon molding.

3. Step B of covering the activated carbon molded body with a non-woven fabric from both sides in the thickness direction
The activated carbon molded body is set in the hollow portion of the thermoformed nonwoven fabric, and another nonwoven fabric is included so as to enclose the activated carbon molded body from the side opposite to the side where the thermoformed nonwoven fabric is arranged as seen from the activated carbon molded body. Was placed, and the entire activated carbon molded body was covered with two non-woven fabrics.

4. Process C in which the activated carbon molded body is covered with the nonwoven fabric from both sides in the thickness direction, the nonwoven fabric is bonded at a position which becomes the peripheral portion of the water purification filter, and the activated carbon molded body is included in the nonwoven fabric.
From the thermoformed non-woven fabric side, a die is heat-pressed at a temperature of 240° C. at a position which becomes the above-mentioned peripheral portion 4 with a heat press having a cylindrical mold having substantially the same shape as the peripheral portion of the water purifying filter, and the upper heat The formed non-woven fabric and the lower non-woven fabric were heat-sealed at the peripheral edge to enclose the activated carbon molded body. Then, the two non-woven fabrics were cut into a circle so that the width of the peripheral portion was 1 to 2 mm, and the water purification filter of Example 2 was obtained.

(Example 3)
30 parts by mass of coal pitch-based activated carbon fiber A (specific surface area 1070 m ² /g, fiber diameter 16 μm) as fibrous activated carbon, and coconut shell activated carbon G (specific surface area 1700 m ² /g, average particle diameter 420 μm) as granular activated carbon 55 5 parts by mass of Unitika Co., Ltd. product name A-02CA as ion exchange fiber, 10 parts by mass of Japan Exlan Industrial Co., Ltd. product name Bi-PUL as acrylic pulp, 100 parts by mass in total are dispersed. To prepare a slurry, pour it into a circular molding frame 5 having a large number of suction small holes 6 as illustrated in FIG. 3, and filter while sucking through the suction small holes 6 to obtain a preform. The preformed body was dried to obtain an activated carbon molded body which was a slurry suction molded body. The obtained activated carbon molded body was disc-shaped, had an outer diameter of 46.3 mm, a thickness of 4.3 mm, a mass of 1.74 g, a hardness of the upper and lower surfaces in the thickness direction of the activated carbon molded body of 54, and activated carbon. The hardness of the side surface of the molded body was 53.

2. Preparation of non-woven fabric containing activated carbon molding A non-woven fabric containing activated carbon molding is a spunbond non-woven fabric consisting of continuous fibers, which is a core-sheath type composite fiber whose core part is made of polyester resin and whose sheath part is made of polyolefin resin. There is a nonwoven fabric in which the continuous fibers that have been deposited are integrated by being partially pressure-bonded by hot embossing, manufactured by Unitika Ltd. under the trade name Elves (registered trademark) S0503WDO (mass 50 g/m ² , thickness). 0.34 mm, MD tensile strength of 215 N/25 mm, CD tensile strength of 100 N/25 mm) were prepared. A mold having a core and a cavity having substantially the same shape as the obtained activated carbon molded body was heated to a temperature of 120° C., and one of the above two nonwoven fabrics was set between the core and the cavity. The non-woven fabric was thermoformed to form a depression having the same shape as the activated carbon molding.

3. Step B of covering the activated carbon molded body with a non-woven fabric from both sides in the thickness direction
The activated carbon molded body is set in the hollow portion of the thermoformed nonwoven fabric, and another nonwoven fabric is included so as to enclose the activated carbon molded body from the side opposite to the side on which the thermoformed nonwoven fabric is arranged as seen from the activated carbon molded body. Was placed, and the entire activated carbon molded body was covered with two non-woven fabrics.

4. Process C in which the activated carbon molded body is covered with the nonwoven fabric from both sides in the thickness direction, the nonwoven fabric is bonded at a position which becomes the peripheral portion of the water purification filter, and the activated carbon molded body is included in the nonwoven fabric.
From the thermoformed non-woven fabric side, a die is heat-pressed at a temperature of 240° C. at a position which becomes the above-mentioned peripheral portion 4 with a heat press having a cylindrical mold having substantially the same shape as the peripheral portion of the water purifying filter, and the upper heat The formed non-woven fabric and the lower non-woven fabric were heat-sealed at the peripheral edge to enclose the activated carbon molded body. Then, the two non-woven fabrics were cut into a circle so that the width of the peripheral portion was 1 to 2 mm, and the water purification filter of Example 3 was obtained.

(Example 4)
1. Step A of preparing activated carbon molded body
15 parts by mass of coal pitch-based activated carbon fiber A (specific surface area 1070 m ² /g, fiber diameter 16 μm) as fibrous activated carbon, and coconut shell activated carbon F (specific surface area 1000 m ² /g, average particle diameter 220 μm) as granular activated carbon 70 5 parts by mass of Unitika Co., Ltd. product name A-02CA as ion exchange fiber, 10 parts by mass of Japan Exlan Industrial Co., Ltd. product name Bi-PUL as acrylic pulp, 100 parts by mass in total are dispersed. To prepare a slurry, pour it into a circular molding frame 5 having a large number of suction small holes 6 as illustrated in FIG. 3, and filter while sucking through the suction small holes 6 to obtain a preform. The preformed body was dried to obtain an activated carbon molded body which was a slurry suction molded body. The obtained activated carbon molded body was disc-shaped, had an outer diameter of 46.3 mm, a thickness of 3.8 mm, a mass of 2.61 g, a hardness of the upper and lower surfaces in the thickness direction of the activated carbon molded body of 51, and activated carbon. The hardness of the side surface of the molded body was 58.

2. Preparation of non-woven fabric containing activated carbon molding A non-woven fabric containing activated carbon molding is a spunbond non-woven fabric consisting of continuous fibers, which is a core-sheath type composite fiber whose core part is made of polyester resin and whose sheath part is made of polyolefin resin. There is a nonwoven fabric in which the continuous fibers that have been deposited are integrated by being partially pressure-bonded by hot embossing, manufactured by Unitika Ltd. under the trade name Elves (registered trademark) S0503WDO (mass 50 g/m ² , thickness). 0.34 mm, MD tensile strength of 215 N/25 mm, CD tensile strength of 100 N/25 mm) were prepared. A mold having a core and a cavity having substantially the same shape as the obtained activated carbon molded body was heated to a temperature of 120° C., and one of the above two nonwoven fabrics was set between the core and the cavity. The non-woven fabric was thermoformed to form a depression having the same shape as the activated carbon molding.

3. Step B of covering the activated carbon molded body with a non-woven fabric from both sides in the thickness direction
The activated carbon molded body is set in the hollow portion of the thermoformed nonwoven fabric, and another nonwoven fabric is included so as to enclose the activated carbon molded body from the side opposite to the side where the thermoformed nonwoven fabric is arranged as seen from the activated carbon molded body. Was placed, and the entire activated carbon molded body was covered with two non-woven fabrics.

4. Process C in which the activated carbon molded body is covered with the nonwoven fabric from both sides in the thickness direction, the nonwoven fabric is bonded at a position which becomes the peripheral portion of the water purification filter, and the activated carbon molded body is included in the nonwoven fabric.
From the thermoformed non-woven fabric side, a die is heat-pressed at a temperature of 240° C. at a position which becomes the above-mentioned peripheral portion 4 with a heat press having a cylindrical mold having substantially the same shape as the peripheral portion of the water purifying filter, and the upper heat The formed non-woven fabric and the lower non-woven fabric were heat-sealed at the peripheral edge to enclose the activated carbon molded body. Then, the two non-woven fabrics were cut into a circle so that the width of the peripheral portion was 1 to 2 mm, and the water purification filter of Example 4 was obtained.

(Example 5)
1. Step A of preparing activated carbon molded body
80 parts by mass of coal pitch-based activated carbon fiber C (specific surface area 1750 m ² /g, fiber diameter 13 μm) as fibrous activated carbon, core-sheath type heat-fusible polyester fiber (manufactured by Unitika Ltd.; Melty 4080, fiber diameter 12 μm, fiber length) 20 parts by mass of 5 mm), a total of 100 parts by mass was used to prepare an activated carbon fiber sheet (dry non-woven fabric) having a basis weight of 65 g/m ² and a thickness of 4.0 mm by a card web method by opening and mixing. This activated carbon fiber sheet is wound on a thin core made of resin, the core is removed, and then the hollow portion formed by removing the core is crushed to produce a core made of the sheet. Further, the above-mentioned sheet is again wound around the core made of the sheet under tension, and the sheath polyester of the core-sheath type heat-fusible polyester fiber is melted by heat treatment or the like to fix the form, and the columnar activated carbon is used. A molded body was obtained. The activated carbon molded body was cut from the side so that the thickness of the activated carbon molded body was 6.3 mm to obtain an activated carbon molded body. The obtained activated carbon molded body was disc-shaped, had an outer diameter of 24.3 mm, a thickness of 6.3 mm, a mass of 0.65 g, a hardness of the upper and lower surfaces in the thickness direction of the activated carbon molded body of 57, activated carbon. The hardness of the side surface of the molded body was 66. Further, in the activated carbon molded body, as illustrated in FIG. 2, the front or back surface of the wound sheet forms the side surface of the activated carbon molded body, and the longitudinal ends of the sheet are arranged in a spiral shape to form the activated carbon molded body. It formed the upper and lower surfaces of the body.

2. Preparation of non-woven fabric containing activated carbon molding A non-woven fabric containing activated carbon molding is a spunbond non-woven fabric consisting of continuous fibers, which is a core-sheath type composite fiber whose core part is made of polyester resin and whose sheath part is made of polyolefin resin. There is a nonwoven fabric in which the continuous fibers that have been deposited are integrated by being partially pressure-bonded by hot embossing, manufactured by Unitika Ltd. under the trade name Elves (registered trademark) S0503WDO (mass 50 g/m ² , thickness). 0.34 mm, MD tensile strength of 215 N/25 mm, CD tensile strength of 100 N/25 mm) were prepared. A mold having a core and a cavity having substantially the same shape as the obtained activated carbon molded body was heated to a temperature of 120° C., and one of the above two nonwoven fabrics was set between the core and the cavity. The non-woven fabric was thermoformed to form a depression having the same shape as the activated carbon molding.

3. Step B of covering the activated carbon molded body with a non-woven fabric from both sides in the thickness direction
The prepared activated carbon molded body is set in the hollow portion of the thermoformed nonwoven fabric so that the longitudinal direction of the sheet constituting the activated carbon molded body is perpendicular to the thickness direction of the water purification filter, and activated carbon molding is performed. Another non-woven fabric was arranged so as to enclose the activated carbon molded product from the side opposite to the side on which the thermoformed non-woven fabric was arranged as viewed from the body, and the whole activated carbon molded product was covered with two non-woven fabrics.

4. Process C in which the activated carbon molded body is covered with the nonwoven fabric from both sides in the thickness direction, the nonwoven fabric is bonded at a position which becomes the peripheral portion of the water purification filter, and the activated carbon molded body is included in the nonwoven fabric.
From the thermoformed non-woven fabric side, a die is heat-pressed at a temperature of 240° C. at a position which becomes the above-mentioned peripheral portion 4 with a heat press having a cylindrical mold having substantially the same shape as the peripheral portion of the water purifying filter, and the upper heat The formed non-woven fabric and the lower non-woven fabric were heat-sealed at the peripheral edge to enclose the activated carbon molded body. Then, two non-woven fabrics were cut into a circle so that the width of the peripheral portion was 1 to 2 mm, and the water purification filter of Example 5 was obtained.

(Example 6)
1. Step A of preparing activated carbon molded body
80 parts by mass of coal pitch-based activated carbon fiber B (specific surface area 1710 m ² /g, fiber diameter 16 μm) as fibrous activated carbon, core-sheath type heat-fusible polyester fiber (manufactured by Unitika Ltd.; Melty 4080, fiber diameter 12 μm, fiber length) 20 parts by mass of 5 mm), a total of 100 parts by mass was used to prepare an activated carbon fiber sheet (dry non-woven fabric) having a basis weight of 65 g/m ² and a thickness of 4.5 mm by the card web method by opening and mixing. This activated carbon fiber sheet is wound on a thin core made of resin, the core is removed, and then the hollow portion formed by removing the core is crushed to produce a core made of the sheet. Further, the above-mentioned sheet is again wound around the core made of the sheet under tension, and the sheath polyester of the core-sheath type heat-fusible polyester fiber is melted by heat treatment or the like to fix the form, and the columnar activated carbon is used. A molded body was obtained. The activated carbon molded body was cut from the side so that the thickness of the activated carbon molded body was 5.3 mm to obtain an activated carbon molded body. The obtained activated carbon molded body was disk-shaped, the outer diameter was 81.3 mm, the thickness was 5.3 mm, the mass was 3.27 g, the hardness of the upper and lower surfaces in the thickness direction of the activated carbon molded body was 56, and the activated carbon was The hardness of the side surface of the molded body was 27. Further, in the activated carbon molded body, as illustrated in FIG. 2, the front or back surface of the wound sheet forms the side surface of the activated carbon molded body, and the longitudinal ends of the sheet are arranged in a spiral shape to form the activated carbon molded body. It formed the upper and lower surfaces of the body.

2. Preparation of non-woven fabric containing activated carbon molding A non-woven fabric containing activated carbon molding is a spunbond non-woven fabric consisting of continuous fibers, which is a core-sheath type composite fiber whose core part is made of polyester resin and whose sheath part is made of polyolefin resin. There is a nonwoven fabric in which the continuous fibers that have been deposited are integrated by being partially pressure-bonded by hot embossing, manufactured by Unitika Ltd. under the trade name Elves (registered trademark) S0503WDO (mass 50 g/m ² , thickness). 0.34 mm, MD tensile strength of 215 N/25 mm, CD tensile strength of 100 N/25 mm) were prepared. A mold having a core and a cavity having substantially the same shape as the obtained activated carbon molded body was heated to a temperature of 120° C., and one of the above two nonwoven fabrics was set between the core and the cavity. The non-woven fabric was thermoformed to form a depression having the same shape as the activated carbon molding.

3. Step B of covering the activated carbon molded body with a non-woven fabric from both sides in the thickness direction
The prepared activated carbon molded body is set in the hollow portion of the thermoformed nonwoven fabric so that the longitudinal direction of the sheet constituting the activated carbon molded body is perpendicular to the thickness direction of the water purification filter, and activated carbon molding is performed. Another non-woven fabric was arranged so as to enclose the activated carbon molded product from the side opposite to the side on which the thermoformed non-woven fabric was arranged as viewed from the body, and the whole activated carbon molded product was covered with two non-woven fabrics.

4. Process C in which the activated carbon molded body is covered with the nonwoven fabric from both sides in the thickness direction, the nonwoven fabric is bonded at a position which becomes the peripheral portion of the water purification filter, and the activated carbon molded body is included in the nonwoven fabric.
From the thermoformed non-woven fabric side, a die is heat-pressed at a temperature of 240° C. at a position which becomes the above-mentioned peripheral portion 4 with a heat press having a cylindrical mold having substantially the same shape as the peripheral portion of the water purifying filter, and the upper heat The formed non-woven fabric and the lower non-woven fabric were heat-sealed at the peripheral edge to enclose the activated carbon molded body. Then, two non-woven fabrics were cut into a circle so that the width of the peripheral portion was 1 to 2 mm, and the water purification filter of Example 6 was obtained.

(Comparative Example 1)
1. Step A of preparing activated carbon molded body
As the granular activated carbon, 95 parts by mass of coconut shell activated carbon E (specific surface area: 1000 m ² /g, average particle diameter: 110 μm), and as acrylic pulp, 5 parts by mass of Bi-PUL, a trade name of Japan Exlan Industrial Co., Ltd., a total of 100 parts by mass. Is dispersed in water to prepare a slurry, poured into a circular molding frame 5 having a large number of suction small holes 6 as illustrated in FIG. 3, and filtered while sucking through the suction small holes 6. A preformed body was obtained, and the preformed body was dried to obtain an activated carbon molded body which was a slurry suction molded body. The obtained activated carbon molded body was disc-shaped, had an outer diameter of 69.3 mm, a thickness of 11.3 mm, a mass of 21.62 g, a hardness of the upper and lower surfaces in the thickness direction of the activated carbon molded body of 90, and activated carbon. The hardness of the side surface of the molded body was 88.

2. Preparation of non-woven fabric containing activated carbon molding A non-woven fabric containing activated carbon molding is a spunbond non-woven fabric consisting of continuous fibers, which is a core-sheath type composite fiber whose core part is made of polyester resin and whose sheath part is made of polyolefin resin. There is a nonwoven fabric in which the continuous fibers that have been deposited are integrated by being partially pressure-bonded by hot embossing, manufactured by Unitika Ltd. under the trade name Elves (registered trademark) S0503WDO (mass 50 g/m ² , thickness). 0.34 mm, MD tensile strength of 215 N/25 mm, CD tensile strength of 100 N/25 mm) were prepared. A mold having a core and a cavity having substantially the same shape as the obtained activated carbon molded body was heated to a temperature of 120° C., and one of the above two nonwoven fabrics was set between the core and the cavity. The non-woven fabric was thermoformed to form a depression having the same shape as the activated carbon molding.

3. Step B of covering the activated carbon molded body with a non-woven fabric from both sides in the thickness direction
The activated carbon molded body is set in the hollow portion of the thermoformed nonwoven fabric, and another nonwoven fabric is included so as to enclose the activated carbon molded body from the side opposite to the side where the thermoformed nonwoven fabric is arranged as seen from the activated carbon molded body. Was placed, and the entire activated carbon molded body was covered with two non-woven fabrics.

4. Process C in which the activated carbon molded body is covered with the nonwoven fabric from both sides in the thickness direction, the nonwoven fabric is bonded at a position which becomes the peripheral portion of the water purification filter, and the activated carbon molded body is included in the nonwoven fabric.
From the thermoformed non-woven fabric side, a die is heat-pressed at a temperature of 240° C. at a position which becomes the above-mentioned peripheral portion 4 with a heat press having a cylindrical mold having substantially the same shape as the peripheral portion of the water purifying filter, and the upper heat The formed non-woven fabric and the lower non-woven fabric were heat-sealed at the peripheral edge to enclose the activated carbon molded body. Then, the two non-woven fabrics were cut into a circle so that the width of the peripheral portion was 1 to 2 mm, to obtain a water purification filter of Comparative Example 1.

(Comparative example 2)
1. Step A of preparing activated carbon molded body
95 parts by mass of coal pitch-based activated carbon fiber A (specific surface area 1070 m ² /g, fiber diameter 16 μm) as fibrous activated carbon, 5 parts by mass of trade name Bi-PUL manufactured by Japan Exlan Industrial Co., Ltd. as acrylic pulp, total 100 parts by mass. Part is dispersed in water to prepare a slurry, poured into a circular molding frame 5 having a large number of suction small holes 6 as illustrated in FIG. 3, and filtered while sucking through the suction small holes 6. To obtain a preformed body, and the preformed body was dried to obtain an activated carbon molded body which was a slurry suction molded body. The obtained activated carbon molded body was disk-shaped, the outer diameter was 54.3 mm, the thickness was 4.8 mm, the mass was 1.43 g, the hardness of the upper and lower surfaces in the thickness direction of the activated carbon molded body was 39, and the activated carbon was The hardness of the side surface of the molded body was 12.

2. Preparation of non-woven fabric containing activated carbon molding A non-woven fabric containing activated carbon molding is a spunbond non-woven fabric consisting of continuous fibers, which is a core-sheath type composite fiber whose core part is made of polyester resin and whose sheath part is made of polyolefin resin. There is a nonwoven fabric in which the continuous fibers that have been deposited are integrated by being partially pressure-bonded by hot embossing, manufactured by Unitika Ltd. under the trade name Elves (registered trademark) S0503WDO (mass 50 g/m ² , thickness). 0.34 mm, MD tensile strength of 215 N/25 mm, CD tensile strength of 100 N/25 mm) were prepared. A mold having a core and a cavity having substantially the same shape as the obtained activated carbon molded body was heated to a temperature of 120° C., and one of the above two nonwoven fabrics was set between the core and the cavity. The non-woven fabric was thermoformed to form a depression having the same shape as the activated carbon molding.

3. Step B of covering the activated carbon molded body with a non-woven fabric from both sides in the thickness direction
The activated carbon molded body is set in the hollow portion of the thermoformed nonwoven fabric, and another nonwoven fabric is included so as to enclose the activated carbon molded body from the side opposite to the side on which the thermoformed nonwoven fabric is arranged as seen from the activated carbon molded body. Was placed, and the entire activated carbon molded body was covered with two non-woven fabrics.

4. Process C in which the activated carbon molded body is covered with the nonwoven fabric from both sides in the thickness direction, the nonwoven fabric is bonded at a position which becomes the peripheral portion of the water purification filter, and the activated carbon molded body is included in the nonwoven fabric.
From the thermoformed non-woven fabric side, a die is heat-pressed at a temperature of 240° C. at a position which becomes the above-mentioned peripheral portion 4 with a heat press having a cylindrical mold having substantially the same shape as the peripheral portion of the water purifying filter, and the upper heat The formed non-woven fabric and the lower non-woven fabric were heat-sealed at the peripheral edge to enclose the activated carbon molded body. Then, the two non-woven fabrics were cut into a circle so that the width of the peripheral portion was 1 to 2 mm to obtain a water purification filter of Comparative Example 2.

(Comparative example 3)
1. Step A of preparing activated carbon molded body
85 parts by mass of coal pitch-based activated carbon fiber A (specific surface area 1070 m ² /g, fiber diameter 16 μm) as fibrous activated carbon, 10 parts by mass of Unitika Co., Ltd. trade name A-02CA as ion exchange fiber, and Japan as acrylic pulp A circular molding having a large number of small holes 6 for suction as exemplified in FIG. 3 is prepared by dispersing 100 parts by mass of 5 parts by mass of Bi-PUL manufactured by Exlan Industries Co., Ltd. in water to prepare a slurry. It was poured into the mold 5 and filtered while sucking through the suction small holes 6 to obtain a preform, and the preform was dried to obtain an activated carbon mold which was a slurry suction form. The obtained activated carbon molded body was disc-shaped, had an outer diameter of 54.3 mm, a thickness of 4.8 mm, a mass of 1.99 g, a hardness of the upper and lower surfaces in the thickness direction of the activated carbon molded body of 24, and activated carbon. The hardness of the side surface of the molded body was 0.

2. Preparation of non-woven fabric containing activated carbon molding A non-woven fabric containing activated carbon molding is a spunbond non-woven fabric consisting of continuous fibers, which is a core-sheath type composite fiber whose core part is made of polyester resin and whose sheath part is made of polyolefin resin. There is a nonwoven fabric in which the continuous fibers that have been deposited are integrated by being partially pressure-bonded by hot embossing, manufactured by Unitika Ltd. under the trade name Elves (registered trademark) S0503WDO (mass 50 g/m ² , thickness). 0.34 mm, MD tensile strength of 215 N/25 mm, CD tensile strength of 100 N/25 mm) were prepared. A mold having a core and a cavity having substantially the same shape as the obtained activated carbon molded body was heated to a temperature of 120° C., and one of the above two nonwoven fabrics was set between the core and the cavity. The non-woven fabric was thermoformed to form a depression having the same shape as the activated carbon molding.

3. Step B of covering the activated carbon molded body with a non-woven fabric from both sides in the thickness direction
The activated carbon molded body is set in the hollow portion of the thermoformed nonwoven fabric, and another nonwoven fabric is included so as to enclose the activated carbon molded body from the side opposite to the side where the thermoformed nonwoven fabric is arranged as seen from the activated carbon molded body. Was placed, and the entire activated carbon molded body was covered with two non-woven fabrics.

4. Process C in which the activated carbon molded body is covered with the nonwoven fabric from both sides in the thickness direction, the nonwoven fabric is bonded at a position which becomes the peripheral portion of the water purification filter, and the activated carbon molded body is included in the nonwoven fabric.
From the thermoformed non-woven fabric side, a die is heat-pressed at a temperature of 240° C. at a position which becomes the above-mentioned peripheral portion 4 with a heat press having a cylindrical mold having substantially the same shape as the peripheral portion of the water purifying filter, and the upper heat The formed non-woven fabric and the lower non-woven fabric were heat-sealed at the peripheral edge to enclose the activated carbon molded body. Then, the two non-woven fabrics were cut into a circle so that the width of the peripheral portion was 1 to 2 mm, and the water purification filter of Comparative Example 3 was obtained.

<Evaluation of workability>
For Examples 1 to 6 and Comparative Examples 1 to 3, when the water purification filters were created 10 points each, the non-woven fabric becomes the peripheral portion of the water purification filter in a state in which the activated carbon molded body was covered with the non-woven fabric from both sides in the thickness direction. The cracking and chipping of the activated carbon molded body in the step C of joining at a position and enclosing the activated carbon molded body with a non-woven fabric were evaluated. Evaluation was performed according to the following criteria, and 3 or more points were judged as passing.
A: No cracking or chipping occurred in 10 samples.
◯: Cracking and chipping occurred at 1 to 3 points out of 10 points of the sample.
X: Cracking or chipping occurred at 4 points or more out of 10 points of the sample.

<Evaluation of handleability>
Gaskets made of silicone rubber and having an inner diameter substantially the same as the outer diameter of the water purification filters of Examples 1 to 6 and Comparative Examples 1 to 3 were prepared, and the ease of fitting the water purification filter into the gasket was evaluated. The evaluation was performed by 10 panelists who were familiar with the water purification filter, and the evaluation criteria were as follows. ○ The above results were accepted.
A: 10 out of 10 panelists judged that there was no practical problem.
◯: 6 to 9 out of 10 panelists judged that there was no practical problem.
X: Less than 6 out of 10 panelists judged that there was no practical problem.

<Evaluation of degree of generation of charcoal dust of activated carbon molding>
In the water filter of the present invention, when the activated carbon molded body has a small amount of carbon dust, when the activated carbon molded body is encapsulated by a non-woven fabric, in the heat-sealing step, the sealing portion (non-woven fabrics around the water purifying filter in the peripheral portion of the water purifying filter are connected to each other). It is preferable because it is possible to reduce the entrapment of coal dust in the joined portion). The following criteria were used to evaluate the degree of coal dust generation.
⊚: No coal dust is caught in the seal part.
◯: The amount of carbon dust trapped in the seal is small. (1-2 places)
Δ: Some amount of carbon dust is caught in the seal portion (at two or more places), but there is no problem in the seal portion.

The evaluation results are shown in Table 1.

<Water purification performance of water purification filter>
With respect to the water purification filter of Example 4, a filtration performance test of free residual chlorine measured at a filtration flow rate of 0.1 L/min was performed according to JIS S 3201:2017, and the removal at the time when the total amount of filtered water was 250 L was removed. The rate was 95%, and the filtration capacity for free residual chlorine was 250 L or more. Further, with respect to the water purifying filter of Example 4, according to JIS S 3201:2017, a filtration performance test of 2-MIB measured at a filtration flow rate of 0.1 L/min was performed, and when the total filtered water amount was 150 L. Was 89%, and the filtration capacity of 2-MIB was 150 L or more. Further, the water purification filter of Example 4 was subjected to a soluble lead filtration capacity test measured at a filtration flow rate of 0.1 L/min according to JIS S 3201:2017, and when the total filtered water amount was 150 L. Was 96%, and the soluble lead filtration capacity was 150 L or more.

Claims (6)

An activated carbon molded body containing fibrous activated carbon and granular activated carbon,
A non-woven fabric containing the activated carbon molded body,
A flat water purification filter having a thickness of 1 to 20 mm,
A water purification filter in which the non-woven fabric is bonded to at least a part of a peripheral portion of the water purification filter and encloses the activated carbon molded body. An activated carbon molded body containing fibrous activated carbon,
A non-woven fabric containing the activated carbon molded body,
A flat water purification filter having a thickness of 1 to 20 mm,
The activated carbon molded body is molded in a state in which a sheet containing fibrous activated carbon is wound,
The activated carbon molded body is provided so that the longitudinal direction of the sheet is a direction perpendicular to the thickness direction of the water purification filter,
A water purification filter in which the non-woven fabric is bonded to at least a part of a peripheral portion of the water purification filter and encloses the activated carbon molded body. The water purification filter according to claim 1 or 2, wherein the non-woven fabric is a non-woven fabric composed of continuous fibers. The water purification filter according to claim 3, wherein the continuous fibers are partially pressure-bonded by hot embossing. The water purification filter according to claim 3 or 4, wherein the continuous fiber is a core-sheath type composite fiber, and a melting point of a sheath part of the core-sheath type composite fiber is lower than a melting point of the core part. The water purification filter according to any one of claims 1 to 5, wherein the water purification filter has a density of 0.1 to 0.5 g/cm ³ .