Adsorption sheet, stepped sheet using said adsorption sheet, stepped laminate, and adsorption element

Abstract

The present disclosure provides an adsorption sheet which has excellent tensile strength and is capable of minimizing the likelihood that an adsorbent falls off. Specifically, the present disclosure is an adsorption sheet containing an adsorbent, organic fibers, and a PVA binder having an underwater dissolution temperature of 99°C or lower, wherein: the organic fibers include fibrillated fibers and polyester fibers having a melting point of 105°C or higher; the mass ratio of the content of the adsorbent to the content of the fibrillated fibers (adsorbent content / fibrillated fiber content) is 2.0-12.0, inclusive; and the mass ratio of the content of the polyester fibers to the content of the PVA binder (polyester fiber content / PVA binder content) is 0.30-3.00, inclusive.

Description

Adsorption sheet, stepped sheet using the adsorption sheet, stepped laminate, and adsorption element

[0001] The present invention relates to an adsorption sheet, a stepped sheet using the adsorption sheet, a stepped laminate, and an adsorption element.

[0002] Adsorption sheets are sheets containing porous materials such as silica gel and zeolite. As a method for manufacturing adsorption sheets, for example, a wet papermaking method is known, in which porous materials, fibers, and organic binders are mixed and then papermade.

[0003] Adsorption elements are manufactured by shaping one or more adsorption sheets into a predetermined form or structure. For example, a honeycomb-structured adsorption element can be manufactured by laminating corrugated adsorption sheets onto liner-shaped adsorption sheets using an adhesive to create stepped sheets, then laminating or winding them in a rotor shape to form a stepped laminate, and finally covering the outer periphery of the stepped laminate with a metal film.

[0004] For example, in Example 1 of Patent Document 1, the adsorbent has a pore size of 7.4 Å and a specific surface area of ​​700 g / m². ２ Using 80 wt% Y-type zeolite, 5 wt% polyvinyl alcohol (PVA) as a binder for papermaking, and synthetic pulp as constituent materials, a paper with a basis weight of 75 g / m² was produced by the wet papermaking method. ２ and water absorption capacity of 57 g / m ２ It is stated that an adsorption sheet was obtained. Furthermore, Example 1 of Patent Document 1 describes an adsorption element made using the adsorption sheet.

[0005] Japanese Patent Application Publication No. 2004-268020

[0006] In recent years, there has been a demand for adsorption sheets and adsorption elements using them that offer high processability and performance stability. Specifically, there is a demand for adsorption sheets and adsorption elements using them that have high tensile strength and minimal shedding of the adsorbent.

[0007] However, the adsorption sheet and adsorption element described in Patent Document 1 have the problem that the adsorbent cannot be prevented from falling off even when supported, because PVA does not perform a binder function for adhesion between fibers, between zeolites, and between fibers and zeolites, and furthermore, the tensile strength is significantly inferior.

[0008] This disclosure has been made in view of the above, and aims to provide an adsorption sheet that can suppress the shedding of the adsorbent and has excellent tensile strength. Furthermore, this disclosure aims to provide a stepped sheet, a stepped laminate, and an adsorption element made using the adsorption sheet.

[0009] The inventors conducted extensive research to achieve the above objectives and discovered that these objectives can be achieved by an adsorption sheet containing an adsorbent, organic fibers, and PVA in specific proportions. This disclosure is the result of further research and development.

[0010] This disclosure encompasses the following subjects: 1. An adsorbent sheet comprising an adsorbent, organic fibers, and a polyvinyl alcohol (PVA) binder with a water dissolution temperature of 99°C or lower, wherein the organic fibers include fibrillated fibers and polyester fibers with a melting point of 105°C or higher, the mass ratio of the adsorbent content to the fibrillated fiber content (adsorbent content / fibrillated fiber content) is 2.0 or more and 12.0 or less, and the mass ratio of the polyester fiber content to the PVA binder content (polyester fiber content / PVA binder content) is 0.30 or more and 3.00 or less. 2. The adsorbent sheet according to 1, wherein the adsorbent content is 20.0% by mass or more and 90.0% by mass or less, with the total mass of the adsorbent sheet being 100% by mass. 3. The tap density of the adsorbent is 0.05 g / cm³ ３ The adsorption sheet described in item 1 or 2. Item 4. The cumulative pore volume of the pores with a pore diameter of 2 nm to 30 nm is 0.20 cm³. ３ / g or more, the adsorption sheet according to any one of Items 1 to 3. Item 5. A corrugated sheet obtained by bonding the adsorption sheets according to any one of Items 1 to 4, wherein said planar adsorption sheet and said corrugated adsorption sheet are bonded together, and the corrugated sheet has cells through which air passes. Item 6. A corrugated laminate obtained by laminating the corrugated sheets according to Item 5. Item 7. An adsorption element comprising the corrugated laminate according to Item 6. Item 8. An adsorption element comprising an adsorbent, organic fibers and a polyvinyl alcohol (PVA) binder having a dissolution temperature in water of 99°C or lower, wherein said organic fibers comprise fibrillated fibers and polyester fibers having a melting point of 105°C or higher, a mass ratio of the content of said adsorbent to the content of said fibrillated fibers (content of adsorbent / content of fibrillated fibers) is 2.0 or more and 12.0 or less, and a mass ratio of the content of said polyester fibers to the content of said PVA binder (content of polyester fibers / content of PVA binder) is 0.30 or more and 3.00 or less. Adsorption element. Item 9. The adsorption element according to Item 8, wherein a content ratio of said adsorbent is 20.0% by mass or more and 90.0% by mass or less, where 100% by mass is the total mass of the adsorption element. Item 10. The adsorbent has a tap density of 0.05 g / cm ３ or more, the adsorption element according to Item 8 or 9. Item 11. The adsorption element according to any one of Items 8 to 10, wherein an accumulated pore volume with a pore diameter of 2 nm or more and 30 nm or less is 0.20 cm ３ / g or more.

[0011] The adsorption sheet of the present disclosure is capable of suppressing shedding of the adsorbent and is excellent in tensile strength. Further, since the adsorption sheet of the present disclosure has such properties, the corrugated sheet, corrugated laminate and adsorption element using the adsorption sheet of the present disclosure are excellent in adsorption performance and excellent in strength.

[0012] Fig. 1(A) is a perspective view of a liner-shaped adsorption sheet, Fig. 1(B) is a perspective view of a corrugated adsorption sheet, and Fig. 1(C) is a schematic cross-sectional view of a corrugated sheet obtained by laminating a corrugated adsorption sheet on a liner-shaped adsorption sheet. Fig. 2(A) is a perspective view showing the procedure for forming an adsorption element, and Fig. 2(B) is a perspective view of the adsorption element.

[0013] Hereinafter, preferred embodiments of the present disclosure will be described in detail. The description of the constituent requirements described below may be made based on representative embodiments and specific examples, but the present disclosure is not limited to such embodiments.

[0014] In the present disclosure, the expressions "contain" and "include" include the concepts of "contain", "include", "consist essentially of" and "consist only of".

[0015] In the numerical ranges described stepwise in the present disclosure, the upper limit or lower limit of the numerical range in one step can be arbitrarily combined with the upper limit or lower limit of the numerical range in another step. In addition, in the numerical ranges described in the present disclosure, the upper limit or lower limit of the numerical range may be replaced with a value shown in the examples or a value that can be uniquely derived from the examples.

[0016] In the present disclosure, the description "any number A to any number B" means a range that is greater than or equal to the number A and less than or equal to the number B.

[0017] In the present disclosure, room temperature means a temperature within the range of 20°C to 25°C.

[0018] 1. Adsorption Sheet The adsorption sheet of this disclosure has the following configurations (I), (II), (III), and (IV): (I) It contains an adsorbent, organic fibers, and a polyvinyl alcohol (PVA) binder with a water dissolution temperature of 99°C or lower. (II) The organic fibers include fibrillated fibers and polyester fibers with a melting point of 105°C or higher. (III) The mass ratio of the adsorbent content to the fibrillated fiber content (adsorbent content / fibrillated fiber content) is 2.0 or more and 12.0 or less. (IV) The mass ratio of the polyester fiber content with a melting point of 105°C or higher to the PVA binder content with a water dissolution temperature of 99°C or lower (polyester fiber content with a melting point of 105°C or higher / PVA binder content with a water dissolution temperature of 99°C or lower) is 0.30 or more and 3.00 or less.

[0019] (Adsorbent) In this disclosure, the adsorbent preferably comprises at least one selected from the group consisting of mesoporous silica, metal-organic structures, silica gel, activated carbon, zeolite, activated alumina, porous metals, and synthetic polymers. In this disclosure, from the viewpoint of further suppressing blockage of adsorption sites by the PVA binder, the adsorbent is more preferably composed of at least one selected from the group consisting of mesoporous silica, metal-organic compounds, and synthetic polymers, even more preferably composed of mesoporous silica, and particularly preferably composed of mesoporous silica.

[0020] In this disclosure, mesoporous silica is silicon dioxide (SiO ２ The material is a mesoporous body composed of silica and having uniform and regular pores (mesopores). In this disclosure, the pore diameter of the mesopores of mesoporous silica is usually 2 nm to 50 nm, preferably 2 nm to 30 nm. In this disclosure, the pore diameter of the mesopores of mesoporous silica can be calculated, for example, by analyzing the nitrogen adsorption isotherm obtained from a nitrogen adsorption test using the Barrett-Joyner-Halenda (BJH) method.

[0021] In this disclosure, a metal-organic framework (MOF) typically comprises a compound having an organic ligand and a metal ion. A metal-organic framework is a porous material obtained by the reaction of a compound having an organic ligand and a metal ion.

[0022] In this disclosure, examples of metal ions included in the metal-organic structure include titanium ions, manganese ions, iron ions, cobalt ions, nickel ions, copper ions, zinc ions, aluminum ions, and zirconium ions. In this disclosure, from the viewpoint of environmental considerations, at least one metal ion selected from the group consisting of titanium ions, manganese ions, iron ions, copper ions, zinc ions, aluminum ions, and zirconium ions is preferred.

[0023] In this disclosure, examples of compounds having organic ligands contained in a metal-organic structure include dicarboxylic acid compounds such as terephthalic acid, isophthalic acid, 2-aminoterephthalic acid, 2,5-diaminoterephthalic acid, 2,5-dihydroxyterephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 3,3'-biphenyldicarboxylic acid, fumaric acid, 1H-pyrazole-3,5-dicarboxylic acid, and 2,5-franzicarboxylic acid; tricarboxylic acid compounds such as trimellitic acid, trimesic acid, and biphenyl-3,4',5-tricarboxylic acid; tetracarboxylic acid compounds such as azobenzene-3,3'-5,5'-tetracarboxylic acid and 1,2,3,4-butanetetracarboxylic acid; and imidazole compounds such as imidazole, 2-methylimidazole, 4-methylimidazole, and benzimidazole.

[0024] In the present disclosure, specific examples of metal-organic frameworks include, for example, a metal-organic framework composed of aluminum ions and 1H-pyrazole-3,5-dicarboxylic acid (MOF303), a polymetallic organic framework composed of zirconium ions and fumaric acid (MOF801), a metal-organic framework composed of nickel and 2,5-dihydroterephthalic acid (MOF74-Ni), a metal-organic framework composed of magnesium and 2,5-dihydroterephthalic acid (MOF74-Mg), and the like.

[0025] In the present disclosure, examples of the form of the adsorbent include powder, granule, pellet, tablet, fiber, and the like. In the present disclosure, from the viewpoint of further improving the adsorption performance of the adsorbent, the adsorbent is preferably in the form of powder.

[0026] In the present disclosure, from the viewpoint of further improving the adsorption performance of the adsorbent, the lower limit of the average particle diameter D50 of the adsorbent is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 1 μm or more, and the upper limit of the average particle diameter D50 of the adsorbent is preferably 200 μm or less, more preferably 150 μm or less, still more preferably 100 μm or less, and even more preferably 80 μm or less; these upper limits and lower limits can be arbitrarily combined. In the present disclosure, the average particle diameter D50 of the adsorbent means a particle diameter at 50% of volume distribution measured by a laser diffraction particle size distribution analyzer.

[0027] In the present disclosure, from the viewpoint that the target substance to be adsorbed can be more favorably adsorbed into the pores and the adsorption performance of the adsorbent can be further improved, the lower limit of the specific surface area measured by the BET method (BET specific surface area) of the adsorbent is 100 m ２ / g or more, 200 m ２ / g or more, 300 m ２ / g or more, and 400 m ２ / g or more in order of preference, and the upper limit of the BET specific surface area is 5000 m ２ / g or less, 4000 m ２ / g or less, 3000 m ２ / g or less, 2000 m ２ / g or less, and 1800 m ２Preferably, the values ​​are in the order of less than or equal to / g, and these upper and lower limits can be combined in any way.

[0028] In this disclosure, when the adsorbent is mesoporous silica, the lower limit of the BET specific surface area of ​​the mesoporous silica is 100 m ２ / g or more, 200m ２ / g or more is 300m ２ / g or more and 400m ２ Preferably in the order of 1 / g or more, and the upper limit of the BET specific surface area of ​​mesoporous silica is 5000 m². ２ / g or less, 4000m ２ / g or less, 3000m ２ / g or less, 2000m ２ / g or less and 1800m ２ Preferably, the values ​​are in the order of less than or equal to / g, and these upper and lower limits can be combined in any way.

[0029] In this disclosure, the adsorbent content is preferably 20.0% by mass or more and 90.0% by mass or less, more preferably 30.0% by mass or more and 80.0% by mass or less, even more preferably 40.0% by mass or more and 75.0% by mass or less, and particularly preferably 45.0% by mass or more and 70.0% by mass or less, based on the total mass of the adsorbent sheets as 100% by mass. By setting the adsorbent content within this range, the adsorption capacity of the adsorbent sheets is increased, the tensile strength of the adsorbent sheets is improved, and the shedding of the adsorbent is further suppressed.

[0030] In this disclosure, the lower limit of the adsorbent content is preferably 20.0% by mass, 25.0% by mass, 30.0% by mass, 35.0% by mass, 40.0% by mass, 45.0% by mass, and 50.0% by mass, with the total mass of the adsorbent sheets being 100% by mass, in that order, and the upper limit of the adsorbent content is preferably 90.0% by mass, 85.0% by mass, 80.0% by mass, 75.0% by mass, 70.0% by mass, and 65.0% by mass, with the total mass of the adsorbent sheets being 100% by mass, in that order, and these upper and lower limits can be arbitrarily combined.

[0031] (Organic Fibers) In this disclosure, organic fibers include fibrillated fibers and polyester fibers with a melting point of 105°C or higher as essential components. In this disclosure, organic fibers typically do not include polyvinyl alcohol (PVA) binders with a water dissolution temperature of 99°C or lower.

[0032] In this disclosure, the organic fibers may include non-fibrillated fibers. When the organic fibers include non-fibrillated fibers, the adsorbent sheet can better maintain its corrugated shape when it is, for example, corrugated.

[0033] In this disclosure, the average fiber diameter of the non-fibrillated fibers is preferably 5 μm or more and 30 μm or less. In this disclosure, the lower limit of the average fiber length of the non-fibrillated fibers is preferably 1 mm or more, more preferably 2 mm or more, and the upper limit of the average fiber length of the non-fibrillated fibers is preferably 15 mm or less, more preferably 11 mm or less, and these upper and lower limits can be arbitrarily combined. The non-fibrillated fibers may be a mixture of two or more types of fibers having different average fiber diameters and different average fiber lengths.

[0034] In this disclosure, fibrillated fibers contained in organic fibers refer, for example, to fibers obtained by fibrillating non-fibrillated fibers as described above. Known methods can be used for fibrillation, such as beating methods using beating machines like beaters and refiners.

[0035] In this disclosure, the average fiber diameter of the fibrillated fibers is preferably 5 μm or more and 30 μm or less. In this disclosure, the lower limit of the average fiber length of the fibrillated fibers is preferably 1 mm or more, more preferably 2 mm or more, and the upper limit of the average fiber length of the fibrillated fibers is preferably 15 mm or less, more preferably 11 mm or less, and these upper and lower limits can be arbitrarily combined. The fibrillated fibers may be a mixture of two or more types of fibers having different average fiber diameters and different average fiber lengths.

[0036] In this disclosure, it is preferable that the fibrillated fibers have a Canadian standard filtration efficiency (CSF) of 50 mL or more and less than 800 mL when measured in accordance with JIS P 8121-2.

[0037] In this disclosure, the fibrillated fiber content is preferably 2.0% by mass or more and 15.0% by mass or less, based on a total mass of 100% by mass of the adsorbent sheet. By setting the fibrillated fiber content within this range, the adsorption capacity of the adsorbent sheet is increased, the tensile strength of the adsorbent sheet is improved, and the shedding of the adsorbent is further suppressed.

[0038] In this disclosure, the lower limit of the fibrillated fiber content is preferably 2.0% by mass, 2.5% by mass, 3.0% by mass, 3.5% by mass, 4.0% by mass, and 4.5% by mass, with the total mass of the adsorbent sheets being 100% by mass, in that order, and the upper limit of the fibrillated fiber content is preferably 20.0% by mass, 19.0% by mass, 18.0% by mass, 17.0% by mass, 16.0% by mass, and 15.0% by mass, with the total mass of the adsorbent sheets being 100% by mass, in that order, and these upper and lower limits can be arbitrarily combined.

[0039] In this disclosure, examples of fibrillated fibers included in organic fibers include fibrillated natural fibers, fibrillated synthetic fibers, fibrillated regenerated fibers, fibrillated semi-synthetic fibers, etc., which can be used individually or in combination of two or more.

[0040] Examples of fibrillated natural fibers in this disclosure include fibrillated cotton, fibrillated hemp, and fibrillated pulp, which can be used individually or in combination of two or more.

[0041] Examples of fibrillated synthetic fibers in this disclosure include fibrillated aramid fibers, fibrillated metaaramid fibers, fibrillated polybenzimidazole fibers, fibrillated polybenzoxazole fibers, fibrillated polyimide fibers, fibrillated polyamideimide fibers, fibrillated polyetherketone fibers, fibrillated polyester fibers, fibrillated nylon fibers, and fibrillated phenolic resin fibers. These can be used individually or in combination of two or more.

[0042] Examples of fibrillated regenerated fibers in this disclosure include fibrillated rayon, fibrillated polynosic, fibrillated cupro, etc., which can be used individually or in combination of two or more.

[0043] Examples of fibrillated semi-synthetic fibers in this disclosure include fibrillated acetate fibers, fibrillated triacetate fibers, and fibrillated promix fibers, which can be used individually or in combination of two or more.

[0044] In this disclosure, the organic fibers preferably include fibrillated synthetic fibers and polyester fibers with a melting point of 105°C or higher. In this disclosure, the organic fibers more preferably include fibrillated aramid fibers and polyester fibers with a melting point of 105°C or higher.

[0045] In one embodiment of the present disclosure, the organic fibers may further include chopped fibers in addition to fibrillated fibers and polyester fibers with a melting point of 105°C or higher. In the present disclosure, chopped fibers are fibers different from fibrillated fibers and polyester fibers with a melting point of 105°C or higher. Chopped fibers can be used as a type of organic fiber.

[0046] In one embodiment of the present disclosure, the content of chopped fibers may be 5.0% by mass or more and 30.0% by mass or less, 10.0% by mass or more and 25.0% by mass or less, 12.5% ​​by mass or more and 22.5% by mass or less, 15.0% by mass or more and 21.0% by mass or less, or 17.5% by mass or more and 20.0% by mass or less, with the total mass of the adsorbent sheets being 100% by mass.

[0047] In one embodiment of the present disclosure, the lower limit of the chopped fiber content may be 5.0% by mass, 7.5% by mass, 10.0% by mass, 11.0% by mass, 12.0% by mass, 12.5% ​​by mass, 13.0% by mass, 14.0% by mass, 15.0% by mass, 16.0% by mass, 17.0% by mass, 17.5% by mass, or 18.0% by mass, with the total mass of the adsorbent sheet being 100% by mass, and the upper limit of the chopped fiber content may be the adsorbent sheet With the total mass of the components being 100% by mass, the values ​​may be 30.0% by mass, 29.0% by mass, 28.0% by mass, 27.0% by mass, 26.0% by mass, 25.0% by mass, 24.5% by mass, 24.0% by mass, 23.5% by mass, 23.0% by mass, 22.5% by mass, 22.0% by mass, 21.5% by mass, 21.0% by mass, 20.5% by mass, or 20.0% by mass, and these upper and lower limits can be combined arbitrarily.

[0048] In another embodiment of the present disclosure, the adsorption sheet may include inorganic fibers. Examples of such inorganic fibers include glass fibers, ceramic fibers, ceramic wool fibers, rock wool fibers, and the like.

[0049] In this disclosure, from the viewpoint of better exhibiting the adhesive function of polyethylene fibers and further improving the tensile strength of the adsorption sheet, it is preferable that the melting point of the polyester fibers is 105°C or higher and 140°C or lower. The melting point of the polyester fibers can be measured, for example, by differential scanning calorimetry.

[0050] In this disclosure, the content of polyester fibers with a melting point of 105°C or higher is preferably 5.0% by mass or more and 20.0% by mass or less, based on 100% by mass of the total mass of the adsorbent sheet, from the viewpoint of having superior tensile strength of the adsorbent sheet and further suppressing the shedding of the adsorbent.

[0051] In this disclosure, the lower limit of the content of polyester fibers with a melting point of 105°C or higher is preferably in the order of 2.0% by mass, 2.5% by mass, 3.0% by mass, 3.5% by mass, 4.0% by mass, 4.5% by mass, 5.0% by mass, 5.5% by mass, and 6.0% by mass, with the total mass of the adsorbent sheet being 100% by mass. The upper limit of the content of polyester fibers with a melting point of 105°C or higher is preferably in the order of 20.0% by mass, 19.0% by mass, 18.0% by mass, 17.0% by mass, 16.0% by mass, and 15.0% by mass, with the total mass of the adsorbent sheet being 100% by mass. These upper and lower limits can be combined in any way.

[0052] In this disclosure, the polyester fiber with a melting point of 105°C or higher is preferably a single polyester fiber and / or a sheath-core composite fiber.

[0053] In this disclosure, the polyester fiber with a melting point of 105°C or higher preferably has an average fiber length of 2 mm or more and 11 mm or less.

[0054] (Polyvinyl alcohol binder) The adsorption sheet of this disclosure contains a polyvinyl alcohol (PVA) binder as an essential component, with a water dissolution temperature of 99°C or lower.

[0055] In this disclosure, the form of the PVA binder with a dissolution temperature in water of 99°C or lower is preferably a fibrous PVA binder, from the viewpoint of having superior tensile strength of the adsorption sheet and further suppressing the shedding of the adsorbent.

[0056] In this disclosure, the lower limit of the dissolution temperature of the PVA binder in water is preferably 50°C or higher, more preferably 55°C or higher, and even more preferably 60°C or higher, from the viewpoint of suppressing a decrease in the adsorption capacity of the adsorption sheet.

[0057] In this disclosure, a method for measuring the dissolution temperature of the PVA binder in water is, for example, to place 100 mL of pure water in a beaker, stir it, and heat it in an oil bath until the water temperature reaches 50°C. Then, 0.5 g of PVA binder is added to the heated water, and the water temperature is increased at a heating rate of 2°C / min. The temperature is then measured when the PVA binder begins to dissolve and becomes semi-transparent, as observed visually.

[0058] In this disclosure, it is preferable that the content of the PVA binder with a water dissolution temperature of 99°C or lower is 1.0% by mass or more and 10.0% by mass or less, based on the total mass of the adsorbent sheet being 100% by mass. By setting the content of the PVA binder with a water dissolution temperature of 99°C or lower within this range, the adsorption capacity of the adsorbent sheet is further increased, the tensile strength of the adsorbent sheet is improved, and the shedding of the adsorbent is further suppressed.

[0059] In this disclosure, the lower limit of the content of the PVA binder with a water dissolution temperature of 99°C or lower is preferably in the order of 1.0% by mass, 1.5% by mass, 2.0% by mass, 2.5% by mass, 3.0% by mass, and 3.5% by mass, with the total mass of the adsorbent sheets being 100% by mass, and the upper limit of the content of the PVA binder with a water dissolution temperature of 99°C or lower is preferably in the order of 10.0% by mass, 9.5% by mass, 9.0% by mass, 8.5% by mass, 8.0% by mass, and 7.5% by mass, with the total mass of the adsorbent sheets being 100% by mass, and these upper and lower limits can be arbitrarily combined.

[0060] In this disclosure, the dissolution temperature of the PVA binder in water may be 50°C to 99°C, 52°C to 95°C, 54°C to 90°C, 56°C to 85°C, 58°C to 82°C, or 60°C to 80°C, from the viewpoint of suppressing a decrease in the adsorption capacity of the adsorption sheet.

[0061] (Mass Ratio) In this disclosure, if the mass ratio of the adsorbent content to the fibrillated fiber content (adsorbent content / fibrillated fiber content) is less than 2.0, the fibrillated fiber content becomes too high, resulting in a decrease in the tensile strength of the adsorbent sheet. Furthermore, when a stepped sheet, a stepped laminate, and an adsorbent element are manufactured using this adsorbent sheet, the adsorbent sheet may break or tear during manufacturing, making it difficult to manufacture the stepped sheet, the stepped laminate, and the adsorbent element.

[0062] In this disclosure, if the mass ratio of the adsorbent content to the fibrillated fiber content (adsorbent content / fibrillated fiber content) exceeds 12.0, the adsorbent content increases, leading to adsorbent shedding, and consequently, a decrease in the long-term stability of the adsorption performance. Furthermore, the long-term stability of the adsorption performance of the stepped sheet, stepped laminate, and adsorption element using the adsorption sheet decreases.

[0063] In this disclosure, the lower limit of the mass ratio of the adsorbent content to the fibrillated fiber content (adsorbent content / fibrillated fiber content) is preferably greater than 2.0, 2.2, 2.4, 2.6, and 2.8 in that order, and the upper limit of the mass ratio (adsorbent content / fibrillated fiber content) is preferably less than 12.0, 11.8, 11.6, 11.4, and 11.2 in that order, and these upper and lower limits can be arbitrarily combined.

[0064] In this disclosure, if the mass ratio of the polyester fiber content (melting point of 105°C or higher) to the PVA binder content (dissolution temperature in water of 99°C or lower) is less than 0.30, the PVA binder will cover the adsorption sites of the adsorbent, resulting in reduced adsorption performance. Furthermore, the adsorption performance of the stepped sheet, stepped laminate, and adsorption element using the adsorption sheet will also be reduced.

[0065] In the adsorption sheet of this disclosure, if the mass ratio of the content of polyester fibers with a melting point of 105°C or higher to the content of PVA binder with a water dissolution temperature of 99°C or lower (content of polyester fibers with a melting point of 105°C or higher / content of PVA binder with a water dissolution temperature of 99°C or lower) exceeds 3.00, the adsorbent will fall off and the tensile strength of the adsorption sheet will decrease. The reason for this is presumed to be as follows: Since polyester fibers contribute to increasing the adhesive strength between fibers, and PVA binders contribute to increasing the adhesive strength between adsorbents and between fibers and adsorbents, if the "content of polyester fibers / content of PVA binder" exceeds 3.00, the adhesion between adsorbents and between fibers and adsorbents will be insufficient, and as a result, the adsorbent will fall off and the tensile strength of the adsorption sheet will decrease.

[0066] Furthermore, corrugated sheets, corrugated laminates, and adsorption elements using adsorption sheets with a "polyester fiber content / PVA binder content" ratio exceeding 3.00 will experience a decrease in long-term stability of adsorption performance and a decrease in strength.

[0067] In this disclosure, the lower limit of the mass ratio (content of polyester fibers with a melting point of 105°C or higher / content of PVA binder with a water dissolution temperature of 99°C or lower) to the content of polyester fibers with a water dissolution temperature of 99°C or lower is preferably greater than 0.30, 0.32, 0.34, 0.36, and 0.38 in that order, and the upper limit of the said mass ratio (content of polyester fibers with a melting point of 105°C or higher / content of PVA binder with a water dissolution temperature of 99°C or lower) is preferably less than 3.00, 2.98, 2.96, 2.94, 2.92, and 2.90 in that order, and these upper and lower limits can be arbitrarily combined.

[0068] In one embodiment of the present disclosure, the adsorption sheet of the present disclosure may contain an adsorbent, fibrillated fibers, polyester fibers with a melting point of 105°C or higher, chopped fibers, and a PVA binder with a water dissolution temperature of 99°C or lower. In this embodiment, the total content of the adsorbent, fibrillated fibers, polyester fibers with a melting point of 105°C or higher, chopped fibers, and PVA binder with a water dissolution temperature of 99°C or lower may be 75% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, 91% by mass or more, 92% by mass or more, 93% by mass or more, 94% by mass or more, 95% by mass or more, 96% by mass or more, 97% by mass or more, 98% by mass or more, 99% by mass or more, 99.25% by mass or more, 99.5% by mass or more, 99.75% by mass or more, 99.9% by mass or more, or 99.99% by mass or more, when the total mass of the adsorption sheet is taken as 100% by mass.

[0069] (Tap Density) In this disclosure, the tap density of the adsorbent is 0.05 g / cm³ from the viewpoint of having superior tensile strength of the adsorbent sheet. ３ That concludes the disclosure. In this disclosure, the tap density of the adsorbent is preferably 0.30 g / cm³. ３ The following applies:

[0070] In this disclosure, the tap density of the adsorbent is more preferably 0.07 g / cm³ from the viewpoint of further improving the tensile strength of the adsorbent sheet. ３ 0.20g / cm or more ３ More preferably, 0.08 g / cm³ ３ 0.15g / cm or more ３ The following applies:

[0071] The tap density of the adsorbent disclosed herein can be measured in accordance with the metal powder-tap density measurement method (JIS Z 2512:2012). A specific method for measuring the tap density of the adsorbent will be described in the examples below.

[0072] (Target Substance and Supporter) The adsorbent of this disclosure is preferably used to adsorb a target substance. The adsorbent of this disclosure is preferably supported on a support that adsorbs the target substance.

[0073] The adsorption sheet of this disclosure is preferably used to adsorb a target substance. The adsorption sheet of this disclosure is preferably supported on a carrier that adsorbs the target substance.

[0074] The adsorption element of this disclosure is preferably used to adsorb a target substance. The adsorption element of this disclosure is preferably supported on a carrier that adsorbs the target substance.

[0075] Examples of carriers that adsorb the target substance include noble metals, transition metals, alkali metals, alkaline earth metals, amine compounds, and the like.

[0076] Examples of precious metals include gold, silver, platinum, palladium, rhodium, iridium, ruthenium, and osmium.

[0077] Examples of transition metals include scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, cadmium, hafnium, tantalum, tungsten, rhenium, and mendelevium.

[0078] Examples of alkali metals include lithium, sodium, potassium, rubidium, cesium, and francium.

[0079] Examples of alkaline earth metals include beryllium, magnesium, calcium, strontium, barium, and radium.

[0080] Examples of amine compounds include polyethyleneimine, monoethanolamine, diethanolamine, triethanolamine, tetraethyleneaminepentamine, methyldiethanolamine, dibutylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, hexaethylenediamine, benzylamine, metaxylenediamine, polyethyleneimine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and piperazine.

[0081] In this disclosure, it is preferable that the amount of the carrier that adsorbs the target substance is 5 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the adsorbent.

[0082] In this disclosure, the substance in question is preferably a compound with a molecular weight of 500 or less. Examples of compounds with a molecular weight of 500 or less in this disclosure include organofluorine compounds (PFAS), nitrogen oxides (NOx), carbon dioxide, organic acids, inorganic acids, and the like.

[0083] Examples of PFAS include perfluoroalkyl sulfonic acids (PFSAs) such as perfluorooctanesulfonic acid (PFOS) and perfluorohexanesulfonic acid (PFHxS); and perfluorocarboxylic acid compounds (PFCAs) such as perfluorooctanoic acid (PFOA) and perfluorohexanoic acid (PFHxA).

[0084] Examples of NOx include nitric oxide (NO) and nitrogen dioxide (NO). ２ ), nitrogen trioxide (NO ３ ), nitrous oxide (dinitrogen monoxide) (N ２ O), dinitrogen trioxide (N ２ O ３ ), dinitrogen tetroxide (N ２ O ４ ), dinitrogen pentoxide (N ２ O ５ Examples include:

[0085] Examples of organic acids include formic acid, acetic acid, citric acid, lactic acid, malic acid, tartaric acid, oxalic acid, ascorbic acid, salicylic acid, benzoic acid, fumaric acid, gluconic acid, pyruvic acid, propionic acid, butanoic acid, and adipic acid.

[0086] Examples of inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, perchloric acid, sulfurous acid, nitrite, carbonic acid, boric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, chromic acid, dichromate, and hydrocyanic acid.

[0087] (Shape and physical properties of the adsorbent sheet) As shown in Figure 1(A), the adsorbent sheet of this disclosure can be used in a liner shape (flat plate shape), and can also be processed as appropriate to be used in a pleated shape, honeycomb shape, corrugated shape, etc. When processing the adsorbent sheet into a pleated shape, honeycomb shape, corrugated shape, etc., flexibility can be imparted to the adsorbent sheet by allowing sufficient moisture to be adsorbed into the adsorbent so that the adsorbent sheet can be easily bent. Alternatively, the adsorbent sheet may be processed in a semi-dry state where it is completely dry, and then completely dried after processing.

[0088] In this disclosure, the tensile strength of the adsorption sheet is 50 to 100 N / cm, from the viewpoint of providing good bending properties such as step processing. ２ This is preferable. The specific method for measuring the tensile strength of the adsorption sheet will be explained in the examples described later.

[0089] The adsorption sheets of this disclosure typically have pores. In the adsorption sheets of this disclosure, the cumulative pore volume of pores with a diameter of 2 nm to 30 nm is preferably 0.20 cm², from the viewpoint of further increasing the adsorption capacity of the adsorption sheet. ３ It is 1 / g or more. In the adsorption sheet of this disclosure, the cumulative pore volume of pores with a pore diameter of 2 nm to 30 nm is preferably 2.0 cm³. ３ It is less than or equal to / g. In this disclosure, the cumulative pore volume (cm³) of the adsorption sheet has a pore diameter of 2 nm to 30 nm. ３ The specific surface area ( / g) can usually be measured using an automatic specific surface area measuring device.

[0090] In the adsorption sheet of this disclosure, the cumulative pore volume with a pore diameter of 2 nm to 30 nm is preferably 0.30 cm², from the viewpoint of further increasing the adsorption capacity of the adsorption sheet. ３ / g or more 1.50cm ３ less than or equal to 0.35 cm / g, more preferably 0.35 cm ３ / g or more 1.0cm ３ Less than or equal to / g, more preferably 0.40 cm ３ / g or more 0.75cm ３ It is less than or equal to / g.

[0091] In this disclosure, from the viewpoint of improving bendability such as step workability, the lower limit of the thickness of the adsorption sheet is preferably 0.1 mm or more, the upper limit of the thickness of the adsorption sheet is preferably 0.9 mm or less, more preferably 0.7 mm or less, and these upper and lower limits can be arbitrarily combined.

[0092] In this disclosure, from the viewpoint of improving bendability such as step workability, the lower limit of the basis weight of the adsorbent sheet is preferably 25 g / m². ２ More preferably 40 g / m ２ The above conditions apply, and the upper limit of the basis weight of the adsorption sheet is preferably 200 g / m². ２ More preferably, 150 g / m ２ The following limits apply, and these upper and lower limits can be combined in any way.

[0093] 2. Method for Manufacturing Adsorbent Sheets Methods for manufacturing adsorbent sheets include, for example, the wet papermaking method. When manufacturing an adsorbent sheet by the wet papermaking method, for example, a method comprising the following steps (1), (2), and (3) in this order can be used. Step (1): An adsorbent, fibrillated fibers, polyester fibers with a melting point of 105°C or higher, and a PVA binder with a water dissolution temperature of 99°C or lower are added to an aqueous solvent and stirred at room temperature to produce a slurry. The mass ratio of the adsorbent content to the fibrillated fiber content (adsorbent content / fibrillated fiber content) is 2.0 or more and 12.0 or less, and the mass ratio of the polyester fiber content with a melting point of 105°C or higher to the PVA binder content with a water dissolution temperature of 99°C or lower (polyester fiber content / PVA binder content) is 0.30 or more and 3.00 or less. Step (3) Then, the obtained sheet-like material is heat-pressed using a heating press to obtain an adsorption sheet.

[0094] In step (1) above, a mixer can be used for stirring.

[0095] In step (1) described above, the stirring time is usually between 1 minute and 10 minutes.

[0096] In step (2) above, the basis weight of the resulting sheet-like material is 40 to 150 g / m². ２ It is preferable to manufacture the paper in such a manner.

[0097] In step (2) above, a polymer flocculant can be added. The amount of polymer flocculant used is preferably 1 part by mass or less, more preferably 0.5 parts by mass or less, even more preferably 0.1 parts by mass or less, even more preferably 0.05 parts by mass or less, and particularly preferably 0.03 parts by mass or less, per 100 parts by mass of adsorbent.

[0098] In step (3) described above, it is preferable that the temperature used for heat pressing is below the melting point of the polyester fibers.

[0099] In step (3) above, the time for heat pressing is usually between 1 minute and 10 minutes.

[0100] 3. Corrugated Sheet The corrugated sheet of the present disclosure is manufactured using the adsorption sheet of the present disclosure. More specifically, the corrugated sheet of the present disclosure is a corrugated sheet made by laminating the adsorption sheets of the present disclosure, wherein a planar adsorption sheet of the present disclosure and a corrugated adsorption sheet of the present disclosure are laminated together and have cells through which air passes.

[0101] Figure 1(B) shows an example of adsorption sheet processing, specifically an adsorption sheet 1B processed into a corrugated shape. Figure 1(C) shows a stepped sheet formed by laminating the corrugated adsorption sheet 1B shown in Figure 1(B) onto the liner-shaped adsorption sheet 1A shown in Figure 1(A).

[0102] As shown in Figure 1(C), the stepped sheet of the present disclosure is manufactured by joining multiple bottom portions 10 of a corrugated adsorption sheet 1B to the surface 11 of a liner-shaped adsorption sheet 1A, thereby forming numerous cells through which air can pass when a flat adsorption sheet and a corrugated adsorption sheet are bonded together.

[0103] In this disclosure, a method for joining multiple bottom portions 10 of a corrugated adsorption sheet 1B to the surface 11 of a liner-shaped adsorption sheet 1A is, for example, a joining method using an adhesive 12, as shown in Figure 1(C).

[0104] As an adhesive, silica-based inorganic adhesives are preferably used from the viewpoint of improving heat resistance. Examples of silica-based inorganic adhesives include water glass-based adhesives, silica sol-based adhesives, and alumina sol-based adhesives.

[0105] The adhesive may be a mixture of an inorganic adhesive and an organic adhesive. Examples of organic adhesives include phenolic resin adhesives, epoxy resin adhesives, acrylic resin adhesives, urethane resin adhesives, polyester resin adhesives, melamine resin adhesives, silicone resin adhesives, fluororesin adhesives, and vinyl acetate resin adhesives.

[0106] 4. Laminated Corrugated Sheets The laminated corrugated sheet of this disclosure is manufactured using the laminated corrugated sheets of this disclosure. More specifically, the laminated corrugated sheet of this disclosure is a laminate formed by laminating laminated corrugated sheets. Examples of methods for laminating laminated corrugated sheets include laminating multiple flat laminated sheets, and laminating laminated corrugated sheets by winding them.

[0107] Figure 2 shows an example of a stepped sheet laminate. The stepped sheet laminate 2 shown in Figure 2(B) is formed by winding the stepped sheet shown in Figure 1(C) in a rotor shape, as shown in Figure 2(A), and exhibits a honeycomb structure.

[0108] In the stepped sheet laminate of this disclosure, from the viewpoint of further improving the strength of the stepped sheet laminate and further improving the amount of air that can pass through the stepped sheet laminate, the number of cells per unit area of ​​the surface through which air passes (cells / cm²) ２ ) is 80 pieces / cm ２ More than 135 pieces / cm ２ The following is preferable: 85 pieces / cm ２ More than 120 pieces / cm ２ The following are preferable.

[0109] 5. Adsorption Element The adsorption element of this disclosure is an adsorption element made of the stepped laminate of this disclosure. The adsorption element of this disclosure is manufactured using the stepped laminate of this disclosure. The adsorption element of this disclosure is manufactured by laminating one or more stepped sheets according to the application and purpose to form a stepped laminate, and then performing core, outer plate and end face treatment on the stepped laminate. The adsorption element is also generally referred to as a desiccant rotor.

[0110] In this disclosure, for example, a straight-flow adsorption element can be manufactured by using a pleated adsorption sheet, and a parallel-flow adsorption element can be manufactured by using a honeycomb-shaped stepped sheet. Both the straight-flow adsorption element and the parallel-flow adsorption element have a structure with a large contact area with the air to be treated, resulting in high adsorption performance of the air to be treated and reduced pressure loss of the adsorption element. Furthermore, the parallel-flow adsorption element is superior to the straight-flow adsorption element in terms of preventing clogging due to mist, dust, etc., reducing pressure loss, and being lighter, and can therefore be used in adsorption and desorption processing equipment.

[0111] In another embodiment of the present invention, the adsorption element of the present disclosure is an adsorption element containing an adsorbent, organic fibers, and a polyvinyl alcohol (PVA) binder with a water dissolution temperature of 99°C or lower, wherein the organic fibers include fibrillated fibers and polyester fibers with a melting point of 105°C or higher, the mass ratio of the adsorbent content to the fibrillated fiber content (adsorbent content / fibrillated fiber content) is 2.0 or more and 12.0 or less, and the mass ratio of the polyester fiber content to the PVA binder content (polyester fiber content / PVA binder content) is 0.30 or more and 3.00 or less.

[0112] The adsorption element of this disclosure can be manufactured, for example, by using fibrillated fibers and polyester fibers with a melting point of 105°C or higher to produce a sheet by a wet papermaking method, then laminating the sheets to produce a stepped laminate, and finally impregnating the stepped laminate with an aqueous solution containing an adsorbent and a polyvinyl alcohol (PVA) binder with a water dissolution temperature of 99°C or lower.

[0113] The present invention will be described more specifically below based on examples, but the present invention is not limited to the embodiments of these examples. In the following examples and comparative examples, "room temperature" means a temperature within the range of 20°C to 25°C.

[0114] First, we will explain the measurement and evaluation methods.

[0115] <Method for measuring tap density of adsorbent> The tap density (g / cm³) of the adsorbent mesoporous silica was measured in accordance with the method for measuring tap density of metal powder (JIS Z 2512:2012). ３ The tap density was measured. Specifically, mesoporous silica was dried and prepared as a sample to ensure uniformity. A transparent resin measuring container (100 mL) with graduations was prepared. The sample was placed in the measuring container and filled until the sample overflowed the top of the container. Then, the sample was leveled using a leveling plate. The measuring container was set in a tapping device and tapped at a rate of twice per second for two minutes. After tapping, additional taps were performed until the volume of the sample no longer decreased. The mass and volume of the sample after tapping were measured, and the tap density was calculated using the following formula: Tap density = Mass of sample after tapping / Volume of sample after tapping

[0116] <Method for measuring the tensile strength of the adsorption sheet> The tensile strength (N / cm) of the adsorption sheet is measured in accordance with JIS P8113:2006. ２ The tensile strength (N / cm²) was measured. Specifically, a test specimen measuring 25 mm in width and 100 mm in length was prepared, set in a small benchtop testing machine (Shimadzu Corporation's "EZ-LX"), and the specimen was pulled at a speed of 20 mm / min until it broke. ２ ) was measured.

[0117] <Method for measuring the cumulative pore volume (cm³) of pores with a diameter of 2 nm to 30 nm in an adsorption sheet> 30 mg of the adsorption sheet obtained in each example and comparative example was taken as a sample, vacuum-dried at 130°C for 12 hours, weighed, and measured using an automatic specific surface area analyzer ("GEMINI VII2390" manufactured by Micromeritics). The amount of adsorption was measured at a relative pressure of 0.95 of nitrogen gas at the boiling point of liquid nitrogen (-195.8°C), and the cumulative pore volume (cm³) of pores with a diameter of 2 nm to 30 nm was measured. ３ We calculated ( / g).

[0118] <Method for evaluating adsorbent detachment> Using adhesive tape specified in JIS Z 0237, the adhesive tape was attached to the surface of the adsorbent sheet. The attached adhesive tape was peeled off vertically at a constant speed. If the value obtained by dividing the mass (g) of the adsorbent sheet after peeling off the adhesive tape by the mass (g) of the adsorbent sheet before the adhesive tape was attached was greater than 0.95, it was determined that there was no adsorbent detachment; if it was 0.95 or less, it was determined that there was adsorbent detachment.

[0119] (Example 1) 60.0 parts by mass of mesoporous silica ("MCM-41" manufactured by Sigma-Aldrich, mesopore diameter: 3 nm to 20 nm), 6.1 parts by mass of fibrillated aramid fibers, 10.7 parts by mass of polyester fibers with a melting point of 120°C (average fiber length 6 mm), 3.7 parts by mass of polyvinyl alcohol (PVA) binder with a water dissolution temperature of 60°C to 80°C, and 19.5 parts by mass of chopped fibers were added to pure water and stirred at room temperature for 5 minutes using a mixer. Then, 0.01 parts by mass of polymer flocculant was added, resulting in a basis weight of 130 g / m². ２ The material was formed into a sheet using a wet papermaking machine (manufactured by Toyo Seiki Seisakusho Co., Ltd.). Then, an adsorbent sheet was obtained by heat pressing at 120°C for 3 minutes using a steam-heated press (manufactured by Toyobo Engineering Co., Ltd.). The chopped fibers used were not fibrillated fibers, nor were they polyester fibers with a melting point of 105°C or higher. A PVA binder with a water dissolution temperature of 60°C to 80°C means that the PVA binder gradually begins to dissolve in water from 60°C and completely dissolves in water at 80°C.

[0120] (Example 2) An adsorbent sheet was obtained by the same method as in Example 1, except that 65.0 parts by mass of mesoporous silica, 6.6 parts by mass of fibrillated aramid fibers, 2.5 parts by mass of polyester fibers (average fiber length 6 mm) with a melting point of 120°C, 6.4 parts by mass of a PVA binder with a water dissolution temperature of 60°C to 80°C, 19.5 parts by mass of chopped fibers, and 0.01 parts by mass of a polymer flocculant were used.

[0121] (Example 3) An adsorption sheet was obtained by the same method as in Example 1, except that 60.0 parts by mass of mesoporous silica, 6.1 parts by mass of fibrillated aramid fibers, 7.5 parts by mass of polyester fibers (average fiber length 6 mm) with a melting point of 120°C, 6.8 parts by mass of a PVA binder with a water dissolution temperature of 60°C to 80°C, 19.5 parts by mass of chopped fibers, and 0.01 parts by mass of a polymer flocculant were used.

[0122] (Example 4) An adsorbent sheet was obtained by the same method as in Example 1, except that 50.0 parts by mass of mesoporous silica, 17.2 parts by mass of fibrillated aramid fibers, 6.9 parts by mass of polyester fibers (average fiber length 6 mm) with a melting point of 120°C, 6.3 parts by mass of a PVA binder with a water dissolution temperature of 60°C to 80°C, 19.5 parts by mass of chopped fibers, and 0.01 parts by mass of a polymer flocculant were used.

[0123] (Example 5) An adsorbent sheet was obtained by the same method as in Example 1, except that 60.0 parts by mass of mesoporous silica, 5.4 parts by mass of fibrillated aramid fibers, 7.9 parts by mass of polyester fibers (average fiber length 6 mm) with a melting point of 120°C, 7.2 parts by mass of PVA binder with a water dissolution temperature of 60°C to 80°C, 19.5 parts by mass of chopped fibers, and 0.01 parts by mass of polymer flocculant were used.

[0124] (Comparative Example 1) An adsorption sheet was obtained by the same method as in Example 1, except that 60.0 parts by mass of mesoporous silica, 6.1 parts by mass of fibrillated aramid fibers, 2.6 parts by mass of polyester fibers (average fiber length 6 mm) with a melting point of 120°C, 11.8 parts by mass of a PVA binder with a dissolution temperature in water of 60°C to 80°C, 19.5 parts by mass of chopped fibers, and 0.01 parts by mass of a polymer flocculant were used.

[0125] (Comparative Example 2) An adsorption sheet was obtained by the same method as in Example 1, except that 60.0 parts by mass of mesoporous silica, 6.1 parts by mass of fibrillated aramid fibers, 11.4 parts by mass of polyester fibers (average fiber length 6 mm) with a melting point of 120°C, 2.9 parts by mass of a PVA binder with a water dissolution temperature of 60°C to 80°C, 19.5 parts by mass of chopped fibers, and 0.01 parts by mass of a polymer flocculant were used.

[0126] (Comparative Example 3) An adsorption sheet was obtained by the same method as in Example 1, except that 40.0 parts by mass of mesoporous silica, 33.3 parts by mass of fibrillated aramid fibers, 3.8 parts by mass of polyester fibers (average fiber length 6 mm) with a melting point of 120°C, 3.4 parts by mass of a PVA binder with a dissolution temperature in water of 60°C to 80°C, 19.5 parts by mass of chopped fibers, and 0.01 parts by mass of a polymer flocculant were used.

[0127] (Comparative Example 4) An adsorption sheet was obtained by the same method as in Example 1, except that 60.0 parts by mass of mesoporous silica, 4.7 parts by mass of fibrillated aramid fibers, 8.3 parts by mass of polyester fibers (average fiber length 6 mm) with a melting point of 120°C, 7.5 parts by mass of a PVA binder with a water dissolution temperature of 60°C to 80°C, 19.5 parts by mass of chopped fibers, and 0.01 parts by mass of a polymer flocculant were used.

[0128] The results for each example and comparative example are shown in Table 1.

[0129]

[0130] [Discussion of Results] The adsorbent sheets obtained in Examples 1 to 5 were able to suppress the shedding of the adsorbent and exhibited excellent tensile strength. The adsorbent sheets obtained in Comparative Examples 1 and 3 were able to suppress the shedding of the adsorbent, but their tensile strength was significantly inferior to that of the respective examples. The adsorbent sheet obtained in Comparative Example 2 was unable to suppress the shedding of the adsorbent and also exhibited significantly inferior tensile strength compared to that of the respective examples. The adsorbent sheet obtained in Comparative Example 4 showed tensile strength equivalent to that of the respective examples, but was unable to suppress the shedding of the adsorbent.

[0131] 1A. Liner-shaped adhesive sheet 1B. Corrugated adhesive sheet 2. Layered sheet laminate 10. Multiple bottoms of the corrugated adhesive sheet 1B 11. Surface of the liner-shaped adhesive sheet 1A 12. Adhesive

Claims

1. An adsorbent sheet comprising an adsorbent, organic fibers, and a polyvinyl alcohol (PVA) binder with a water dissolution temperature of 99°C or lower, wherein the organic fibers include fibrillated fibers and polyester fibers with a melting point of 105°C or higher, the mass ratio of the adsorbent content to the fibrillated fiber content (adsorbent content / fibrillated fiber content) is 2.0 or more and 12.0 or less, and the mass ratio of the polyester fiber content to the PVA binder content (polyester fiber content / PVA binder content) is 0.30 or more and 3.00 or less.

2. The adsorbent sheet according to claim 1, wherein the content ratio of the adsorbent is 20.0% by mass or more and 90.0% by mass or less, with the total mass of the adsorbent sheet being 100% by mass.

3. The tap density of the adsorbent is 0.05 g / cm³. ３ The adsorption sheet according to claim 1 or 2.

4. The cumulative pore volume of pores with a diameter of 2 nm to 30 nm is 0.20 cm³. ３ The adsorption sheet according to claim 1 or 2, wherein the amount is 1g or more.

5. A stepped sheet formed by laminating the adsorption sheets described in claim 1 or 2, wherein a planar adsorption sheet and a corrugated adsorption sheet are laminated together and the stepped sheet has cells through which air passes.

6. A laminated body formed by laminating the laminated sheets described in claim 5.

7. An adsorption element comprising a stepped laminate as described in claim 6.

8. An adsorption element comprising an adsorbent, organic fibers, and a polyvinyl alcohol (PVA) binder with a water dissolution temperature of 99°C or lower, wherein the organic fibers include fibrillated fibers and polyester fibers with a melting point of 105°C or higher, the mass ratio of the adsorbent content to the fibrillated fiber content (adsorbent content / fibrillated fiber content) is 2.0 or more and 12.0 or less, and the mass ratio of the polyester fiber content to the PVA binder content (polyester fiber content / PVA binder content) is 0.30 or more and 3.00 or less.

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