JP2012148236A - Sheet for adsorption - Google Patents

Abstract

To provide an adsorbing sheet having an adsorbent / organic fiber containing an adsorbent / organic fiber with improved thermal conductivity and improved adsorption / desorption characteristics to facilitate heat exchange with a contact layer. is there.
An adsorbing sheet comprising an adsorbent / organic fiber, the adsorbing sheet comprising a heat conductor having a thermal conductivity of 10 W / m · K or more.
[Selection figure] None

Description

  The present invention relates to a suction sheet.

Utilizing the adsorption capacity and desorption capability of the adsorbent, the organic gas (VOC), carbon monoxide, carbon dioxide, nitrogen oxides (NO _X) such as a gas removal system, heat exchange or heat transfer systems, humidity control (dehumidification (Or humidification) systems have been developed. The adsorbing elements used in these various systems are adsorbents in which an adsorbing layer containing an adsorbent and a binder is provided on a sheet base material such as paper, fabric, film, porous film, metal foil, and metal plate. Or a slurry containing organic fibers and an adsorbent, and the adsorbent sheet obtained from a web prepared by wet papermaking.

  The adsorbing sheet constituting the adsorbing layer on the base sheet is manufactured by applying a coating liquid in which an adsorbent is dispersed in water as a medium together with a binder to the sheet base. Adsorbents include superabsorbent polymers, organic adsorbents such as carboxymethylcellulose, inorganic adsorbents such as silica gel, sepiolite, zeolite, bentonite, attapulgite, diatomaceous earth, activated carbon, porous metal oxide, and aluminum hydroxide. Used mainly. Examples of the binder include (meth) acrylic resin, vinyl acetate resin, (meth) acrylic / styrene copolymer resin, ethylene / vinyl acetate copolymer resin, styrene / butadiene copolymer resin, styrene / acrylonitrile / (meth). An emulsion made of a water-insoluble polymer such as an acrylic acid alkyl ester copolymer resin or vinyl acetate / (meth) acrylic acid alkyl ester copolymer resin is used. However, when these emulsions are used as the binder, gelation of the coating liquid and sedimentation of the adsorbent are likely to occur, the adsorption layer becomes uneven, the coating amount decreases, the coating cannot be performed, the adsorption layer and the sheet base material There were problems such as low binding force. In addition, since the surface of the adsorbent is easily covered with these emulsions, there is a problem that the adsorption characteristics of the obtained adsorption layer are lowered. In addition, depending on the adsorbent, the adsorption characteristics are expressed by a special structure such as an agglomerated structure, a fiber structure, or a ring structure, but there is a problem that the adsorption characteristics are deteriorated because the binder changes the structure. It happened.

  Therefore, as a method for efficiently reproducing the adsorption capacity of the adsorbent contained, a slurry containing organic fibers and adsorbent is prepared, a web using the slurry is prepared by a wet papermaking method, and aeration is performed by pressure heating drying. There has been proposed a method for producing a web having the property and obtaining an adsorbing sheet containing an adsorbent.

  However, the adsorption sheet made mainly of such organic fibers has a low thermal conductivity of the organic fibers, so it is difficult to dissipate heat generated when adsorbing the adsorbent, and heating for desorption is performed. There is a problem that processing is difficult to communicate. Therefore, when performing adsorption / desorption with a fast cycle, the performance of the adsorption sheet cannot be fully utilized.

JP 2003-38928 A JP 2005-87906 A JP 2009-183905 A

  An object of the present invention is to provide an adsorbing sheet having an excellent adsorption / desorption cycle by improving thermal responsiveness during adsorption / desorption even in an adsorption sheet mainly composed of organic fibers.

The above issues
(1) Organic fiber, adsorbent, and heat conductor with a thermal conductivity of 10 W / m · K or more are contained at least, and the content of the heat conductor with a thermal conductivity of 10 W / m · K or more is based on the mass of the sheet for adsorption. 1 to 20% by mass, an adsorption sheet,
(2) It is produced by impregnating or coating a web containing an organic fiber and an adsorbent with a coating liquid containing a thermal conductor having a thermal conductivity of 10 W / m · K or more. The adsorption sheet according to (1),
(3) It is manufactured by impregnating or applying a coating liquid containing an adsorbent and a thermal conductor having a thermal conductivity of 10 W / m · K or more on a web containing organic fibers. The adsorption sheet according to (1),
(4) The adsorbing sheet according to (1), wherein the adsorbing sheet is produced by producing a web containing an organic fiber, an adsorbent, and a thermal conductor having a thermal conductivity of 10 W / m · K or more. ,
It was found that this can be solved.

  According to the present invention, even in an adsorption sheet mainly composed of organic fibers having low thermal conductivity, the thermal responsiveness of the sheet is improved and contained by including a thermal conductor having high thermal conductivity. Adsorbent can be utilized more efficiently.

  The adsorbent used in the present invention contains an oxide of at least one metal atom selected from silicon, titanium, aluminum, tantalum, vanadium, zirconium, zinc, magnesium, calcium and the like. Examples thereof include granular bodies having a large number of pores, composite particles obtained by agglomerating a plurality of single particles having a primary particle diameter of several nanometers, tubular bodies, and aggregates of fibrous materials. More specifically, amorphous aluminum silicate, porous silica, mesoporous silica, zeolite, silica gel, fibrous or tubular aluminum silicate, fibrous or tubular titanium oxide, diatomaceous earth, and the like can be given. Furthermore, organic adsorbents such as a superabsorbent polymer and carboxymethyl cellulose can also be used.

Especially when capturing the moisture in the air and the adsorbate, the specific surface area of the adsorbent is preferably 300~1200g / ^{m 2,} more preferably 500~1200g / ^{m 2,} more preferably 700~1200g / ^{m 2.} When the specific surface area is less than 300 g / m ² , the amount of adsorption to the adsorbent is not sufficient, and the capacity as an adsorption sheet may be insufficient. When the specific surface area exceeds 1200 g / m ² , the adsorption phenomenon to the adsorbate occurs strongly, so that the adsorption / desorption hysteresis becomes too large, and efficient adsorption / desorption may not be performed.

  As a content rate of the adsorption agent with respect to the sheet | seat mass for adsorption, 30-80 mass% is preferable, 40-70 mass% is more preferable, 45-60 mass% is further more preferable. If the adsorbent content is less than 30% by mass, the adsorbed amount may not be sufficient. If the content of the adsorbent exceeds 80% by mass, the adsorbent density becomes too high as compared with the fiber density, so there is a concern that the adsorbent adsorption efficiency may be reduced or the adsorbent sheet strength may be reduced.

  The thermal conductor used in the present invention has a thermal conductivity of 10 W / m · K such as aluminum nitride, aluminum, graphite (graphite), carbon steel, carbon fiber, ferrite (ferrite), silver, copper, nickel, etc. The above heat conductor can be used. For members with a thermal conductivity of less than 10 W / m · K, a large amount of attachment is required to improve the thermal responsiveness of the adsorption sheet, resulting in lower productivity and lower relative adsorbent ratio due to high loading. It is not suitable for improving the expected adsorption / desorption properties. As a content rate of the heat conductor with respect to the sheet | seat mass for adsorption | suction, it is 1-20 mass%, 5-15 mass% is more preferable, and 5-10 mass% is further more preferable. If the content of the heat conductor is less than 1% by mass, sufficient heat conductivity cannot be imparted to the adsorbent sheet. If the content of the heat conductor exceeds 20% by mass, the heat conductor and the binder are added. The pores of the adsorbent are buried.

  Examples of organic fibers used in the present invention include olefin resins, polyester resins, polyvinyl acetate resins, ethylene-vinyl acetate copolymer resins, polyamide resins, acrylic resins, polyvinyl chloride resins, and polyvinylidene chloride resins. Resin, polyvinyl ether resin, polyvinyl ketone resin, polyether resin, polyvinyl alcohol resin, diene resin, polyurethane resin, phenol resin, melamine resin, furan resin, urea resin, aniline resin, Examples thereof include fibers made of unsaturated polyester resins and alkyd resins. In addition, plant fibers such as wood pulp, cocoon, cocoon, cocoon, kenaf, bamboo, linter, bagasse, esparto, and sugarcane, or those obtained by refining them can be used. Further, rayon fibers, lyocell fibers, semi-synthetic fibers such as acetate, fluorine-based resin fibers such as polytetrafluoroethylene (PTFE), silicone-based resin fibers, and the like, which are cellulose regenerated fibers, can also be used.

  As content rate of the organic fiber with respect to the sheet | seat for adsorption | suction of this invention, 20-50 mass% is preferable, 30-45 mass% is more preferable, and 35-40 mass% is further more preferable. If the organic fiber content is less than 20% by mass, sufficient strength may not be maintained as a support for the adsorbent and heat conductor contained. In addition, when the organic fiber content is 50% by mass or more, the content of the adsorbent and the heat conductor is decreased, and a satisfactory adsorption amount may not be ensured. In addition, flame retardant or non-flammable inorganic fibers such as glass fibers can be added to the sheet material for dehumidification of the present invention.

  As a method for producing the adsorbing sheet of the present invention, (I) a method of making a web containing an adsorbent and organic fibers and then supporting the thermal conductor by impregnation or coating, (II) comprising organic fibers A method of impregnating or coating an adsorbent and a heat conductor on a web to be carried out, (III) a method of producing a web by wet papermaking from a slurry containing an adsorbent, a heat conductor and organic fibers, and the like. It is done. According to the present invention, the heat conductor needs to be contained so that heat exchange between the adsorption sheet and the air that is the contact layer can be efficiently performed. Further, the production method of the method (I) and the method (II) in which the contact surface with the contact layer becomes larger is more preferable.

  In the methods (I), (II) and (III), the web can be prepared by a dry method such as a card method or an airlay method, or a wet papermaking method. Is preferred. The wet papermaking method is a method in which a material is dispersed in water at a low concentration and the paper is made up, which is inexpensive, highly uniform, and capable of mass production. Specifically, a web material selected from an adsorbent, a heat conductor, and organic fibers is dispersed in water to prepare a slurry, which is filled with a filler, a dispersant, a thickener, an antifoaming agent, and a paper strength enhancer. Then, a sizing agent, a flocculant, a coloring agent, a fixing agent, and the like are appropriately added, and wet papermaking is performed with a paper machine. As the paper machine, a circular paper machine, a long paper machine, a short paper machine, an inclined paper machine, a combination paper machine in which the same or different types of paper machines are combined, and the like can be used. The wet paper after paper making can be dried using an air dryer, cylinder dryer, suction drum dryer, infrared dryer, or the like to obtain a sheet.

  A coating method (impregnation or coating) is used for supporting the heat conductor or adsorbent and the heat conductor in the methods (I) and (II).

  As the coating liquid, a solution or dispersion containing only a heat conductor or a solution or dispersion containing a heat conductor and an adsorbent is used. As the medium, water, alcohol, ketone or the like can be used alone or in combination. For coating, an impregnation or coating apparatus such as a dip coater, a size press, a gate roll coater, an air knife coater, a blade coater, a comma coater, a bar coater, a gravure coater, and a kiss coater can be used.

  In order to strongly support the heat conductor and the adsorbent on the web, it is preferable to add a synthetic resin to the coating solution. The synthetic resin is not particularly limited. For example, polymers such as polyvinyl alcohol resins, acrylic ester resins, aromatic vinyl compounds, styrene-butadiene rubber resins, vinyl acetate resins, ethylene-vinyl acetate copolymers. At least one or more of a system resin, a silicone resin, a fluorine resin and the like can be used. In the case of a synthetic resin having a strong active group such as a carbonyl group, the synthetic resin may be adsorbed on the surface of the adsorbent and the adsorption characteristics may be deteriorated.

  A polyvinyl alcohol-type resin means the resin which contains a vinyl alcohol polymer in the component. Polyvinyl alcohol resins include polyvinyl alcohol; grafted polyvinyl alcohol styrene / butadiene latex, grafted polyvinyl alcohol acrylic emulsion, and vinyl alcohol polymer adsorbed onto latex or emulsion such as grafted polyvinyl alcohol ethylene / vinyl acetate emulsion. Alternatively, a grafted polyvinyl alcohol resin can be used.

As a sheet | seat for adsorption | suction in this invention, basic weight 30-200 g / m < ² > is preferable, basic weight 40-150 g / m < ² > is more preferable, basic weight 50-100 g / m < ² > is further more preferable. When the basis weight is less than 30 g / m ² , the amount of adsorbent is small and the desired adsorption performance may not be obtained. When the basis weight exceeds 200 g / m ² , the air permeability may be lowered, and the adsorption efficiency of the adsorbent may be lowered.

  As a sheet | seat for adsorption | suction in this invention, thickness 50-500 micrometers is preferable, thickness 70-400 micrometers is more preferable, and thickness 100-300 micrometers is more preferable. When the thickness is less than 50 μm, the sheet strength is lowered and it is difficult to maintain the sheet shape. When the thickness exceeds 500 μm, the air permeability may be lowered and the adsorption efficiency of the adsorbent may be lowered.

  The adsorbing sheet of the present invention includes a woven fabric, a dry nonwoven fabric, and a wet nonwoven fabric composed only of inorganic fibers, such as an inorganic porous film such as a punching metal sheet, a foamed metal sheet, and an aggregate film of inorganic particles, a metal foil, and a metal plate. Alternatively, a knitted fabric or the like may be laminated and combined by bonding or the like.

  The adsorption sheet of the present invention may be used as it is, or may be used after being subjected to secondary processing such as pleating, corrugating, laminating, roll core processing, and donut processing. Further, examples of the use include packaging materials, dehumidifying sheets, interior materials, filters, humidity control elements, heat exchange elements, and the like. Specific examples of humidity control elements and heat exchange elements include dehumidification rotor elements, building air-conditioning vaporization type humidification elements, fuel cell humidification elements, dehumidifier dehumidification elements, water absorption transpiration elements for vending machines, water absorption transpiration elements for cooling, etc. And a dehumidifying rotor element of a desiccant air conditioner.

(Adsorbent)
Table 1 shows the adsorbents used in the examples and comparative examples.

  Adsorbent 1 was prepared by the following method. 400 ml of an aqueous sodium orthosilicate solution diluted with pure water was prepared so that the Si concentration was 383 mmol / L. Separately, aluminum chloride was dissolved in pure water to prepare 400 ml of an aqueous solution having an Al concentration of 450 mmol / L. Next, the sodium orthosilicate aqueous solution was mixed with the aluminum chloride aqueous solution and stirred with a magnetic stirrer. The Si / Al ratio at this time was 0.85. Further, 18 ml of 1N aqueous sodium hydroxide solution was added dropwise to the mixed solution to adjust the pH to 7. The precursor was recovered from this solution by centrifugation and dispersed in 4 L of pure water. After stirring for 1 hour at room temperature, it was transferred to a 4 L sealed container and heated at 98 ° C. for 2 days in a thermostatic bath. After cooling, after washing 3 times by centrifugation, drying was performed at 60 ° C. to obtain an adsorbent 1. When the adsorbent 1 was observed with a transmission electron microscope and a scanning electron microscope, composite particles having a primary particle size of 2 to 40 nm composed of particles having a particle size of 2 to 5 nm constituted an aggregate structure having a size of 0.1 to 100 μm. The aggregate structure had pores of 2 to 20 nm.

The adsorbent 5 was prepared by the following method. To the anatase titanium oxide particles obtained by the sol-gel method, an aqueous 20 mol / kg potassium hydroxide solution is added, and the slurry obtained by heating at 120 ° C. for 24 hours is washed repeatedly with water and then neutralized with acetic acid. After sufficiently washing with water again to remove excess ionic components, a fibrous titanium oxide dispersion liquid aggregated into a network having a concentration of 20% by mass was obtained using a centrifuge. A part of this was dried, the powder was taken out, and the specific surface area was measured by the BET method. As a result, it was 350 m ² / g.

  Table 2 shows thermal conductors used in Examples and Comparative Examples.

Examples 1-6, Comparative Examples 1-2
As a web containing an adsorbent, the adsorbent 1 having a solid content of 50% by mass, polyethylene terephthalate fiber (trade name: Tepyrus (registered trademark), manufactured by Teijin Fibers Ltd., 0.1 dtex × 3 mm) 26 mass %, Polyester heat-fusible core-sheath fiber (trade name: Melty (registered trademark), manufactured by Unitika Ltd., 1.1 dtex × 3 mm) 17% by mass, cellulosic fibrillated fiber (trade name: serisch (registered trademark)) A slurry (solid content concentration 2% by mass) containing 7% by mass of KY-100G (manufactured by Daicel Chemical Industries, Ltd.) was prepared. A flocculant (Percoll 57, manufactured by Ciba Specialty Chemicals) is added to the obtained slurry in an amount of 0.2% by mass with respect to the solid content, and paper is made to a basis weight of 50 g / m ² with a circular net type paper machine. And a web containing organic fibers.

  A coating liquid 1 containing a heat conductor 1 was produced.

Coating liquid 1
Thermal conductor 1 (trade name: MZ-600, manufactured by Air Water Co., Ltd.) 10% by mass
Ethylene-vinyl acetate emulsion 3% by mass
(Product name: Rikabond (registered trademark) BEF9857, manufactured by Chuo Rika Kogyo Co., Ltd.)
1% by mass of polyvinyl alcohol (trade name: JP45, manufactured by Nippon Vinegar Poval Co., Ltd.)
86% by weight of water

  After coating the coating liquid 1 on a web containing an adsorbent and organic fibers using a rod bar, the coating liquid 1 is dried at 90 ° C. for 30 minutes, and the heat conductor 1 is bonded to both sides of the adsorbing sheet mass. 10% by mass (Example 1), 1% by mass (Example 2), 5% by mass (Example 3), 8% by mass (Example 4), 15% by mass (Example 5), 20% by mass (implementation) Example 6) An adsorption sheet carrying 0.5% by mass (Comparative Example 1) and 21% by mass (Comparative Example 2) was produced.

Example 7
Polyethylene terephthalate fiber (trade name: Tepyrus (registered trademark), manufactured by Teijin Fibers Ltd., 0.1 dtex × 3 mm) 57% by mass, polyester heat-fusible core-sheath fiber (trade name: Melty (registered) (Trademark), manufactured by Unitika Ltd., 1.1 dtex × 3 mm), and a web containing 43% by mass of organic fibers having a basis weight of 20 g / m ² was prepared.

A coating liquid 2 containing an adsorbent and a heat conductor was produced.
Adsorbent 1 20% by mass
Thermal conductor 1 5% by mass
Ethylene-vinyl acetate emulsion 7.5% by mass
(Product name: Rikabond (registered trademark) BEF9857, manufactured by Chuo Rika Kogyo Co., Ltd.)
Polyvinyl alcohol (trade name: JP45, manufactured by Nippon Vinegar Poval Co., Ltd.) 2.5% by mass
65% by weight of water

The web containing organic fibers is coated with the coating liquid 2 using a rod bar, the coating layer is 35 g / m ^{2 on} both sides, and the content of the heat conductor 1 with respect to the weight of the adsorption sheet is 10% by mass. An adsorption sheet (Example 7) was produced.

Example 8
In the wet papermaking method, 40 mass% adsorbent 1 in solid content, 10 mass% heat conductor 1 in solid content, polyethylene terephthalate fiber (trade name: Tepyrus (registered trademark), manufactured by Teijin Fibers Ltd., 0.1% dtex × 3 mm) 26% by mass, polyester heat-fusible core-sheath fiber (trade name: Melty (registered trademark), manufactured by Unitika Ltd., 1.1 dtex × 3 mm) 17% by mass, cellulosic fibrillated fiber ( Product name: A slurry (solid content concentration 2% by mass) containing 7% by mass of Selish (registered trademark) KY-100G, manufactured by Daicel Chemical Industries, Ltd. was prepared. A flocculant (trade name: Percoll 57, manufactured by Ciba Specialty Chemicals) was added to the obtained slurry in an amount of 0.2% by mass based on the solid content, and paper was made to a basis weight of 50 g / m ² with a circular net type paper machine. An adsorbent sheet (Example 8) containing an adsorbent, a heat conductor, and organic fibers and containing 10% by mass of the heat conductor relative to the adsorbent sheet was obtained.

Examples 9-15
Except for changing the composition of the web containing the adsorbent and the organic fiber as follows, it contains 10% by mass of the heat conductor 1 with respect to the adsorbing sheet mass in the same manner as in Example 1. An adsorption sheet was obtained.

Adsorbent 1 / polyethylene terephthalate fiber / polyester heat-fusible core-sheath fiber / cellulosic fibrillated fiber =
30% by mass / 40% by mass / 26% by mass / 4% by mass (Example 9)
40% by mass / 33% by mass / 21% by mass / 6% by mass (Example 10)
60% by mass / 20% by mass / 13% by mass / 7% by mass (Example 11)
70% by mass / 14% by mass / 9% by mass / 7% by mass (Example 12)
80% by mass / 8% by mass / 5% by mass / 7% by mass (Example 13)
25% by mass / 43% by mass / 28% by mass / 4% by mass (Example 14)
85% by mass / 5% by mass / 3% by mass / 7% by mass (Example 15)

Examples 16-19
Except for changing the heat conductor 1 to the heat conductor 2 (Example 16), the heat conductor 3 (Example 17), the heat conductor 4 (Example 18), and the heat conductor 5 (Example 19). In the same manner as in Example 1, a suction sheet was produced.

Examples 20-23
Except for changing the adsorbent 1 to adsorbent 2 (Example 20), adsorbent 3 (Example 21), adsorbent 4 (Example 22), adsorbent 5 (Example 23), Similarly, a suction sheet was produced.

Comparative Examples 3-7
Except having changed the heat conductor 1 into the heat conductor 6, the sheet | seat for adsorption | suction was produced by the method similar to Example 20, 20-23.

<Desorption rate evaluation test>
The adsorption rate of the adsorbent was evaluated for the adsorption sheets of Examples and Comparative Examples by the following method.

Examples and adsorbent contained in the adsorption sheet of Comparative Example content W _{A (%)} was determined by the following method.

Adsorption sheet produced by method (I):
Mass of web W _B before heat conductor coating when dried at 90 ° C. for 2 hours in advance, adsorbent blending ratio W _C (%) in web, sheet for adsorption when dried at 90 ° C. for 2 hours than the mass W _D, it was calculated from the following formula, wherein.
W _A (%) = W _B × W _C / W _D

Adsorption sheet prepared by method (II):
Adsorbent content ratio W _E of the coating liquid _(%), the web mass before coating was dried for 2 hours at a temperature 90 ° C. W _F, from suction seat weight W _D, was calculated from the following formula, wherein.
_{W A (%) = (W} D -W F) × W E / W D

Adsorption sheet prepared by method (III):
From the adsorbent compounding ratio W _G (%) in the web, it was calculated from the following formula.
W _A (%) = W _G

The desorption rate of the adsorption sheet was determined by the following method. The adsorption sheet was treated for 2 hours with a hot air dryer set at a temperature of 90 ° C. to obtain a mass W ₀ at that time. The adsorption sheet was treated for 2 hours in an environmental test chamber adjusted to a temperature of 25 ° C. and a relative humidity of 80%, and the mass at that time was regarded as the equilibrium mass to obtain mass W ₁ . The equilibrated sheet for adsorption was immediately placed in an environmental test cabinet set at a temperature of 40 ° C. and a relative humidity of 20% for 20 seconds, and taken out after 20 seconds to obtain a mass W ₂ at that time.

From the formula described below, the desorption rate of adsorbed moisture of the adsorbent contained in the adsorbing sheet was obtained.
Desorption rate D (%) = (W ₁ −W ₂ ) / (W ₁ −W ₀ ) × 100

  About the desorption rate of each adsorption | suction sheet | seat of an Example and a comparative example, it compares with the web for adsorption | suction which does not contain a heat conductor, and it shows in Table 3 as follows.

◎: Desorption rate improvement 10% or more ○: Desorption rate improvement 5% or more to less than 10% △: Desorption rate improvement 3% or more to less than 5% ×: Desorption rate improvement less than 3%

The adsorption web containing no heat conductor was produced by the method described below.
Adsorbing web to be compared with the adsorbing sheet prepared by method (I): containing an adsorbent in the same amount as the adsorbing sheet to be compared, and adsorbent and organic fiber prepared by wet papermaking A web for adsorption comprising.
Adsorption web to be compared with the adsorption sheet prepared by method (II): A coating liquid containing an adsorbent and a binder on a web composed of organic fibers is equivalent to the adsorption sheet for comparison. An adsorbing web comprising an amount of adsorbent by coating.
Adsorption web to be compared with the adsorption sheet prepared by method (III): It contains only the same amount of adsorbent as the adsorption sheet to be compared, and only the adsorbent and organic fiber prepared by the wet papermaking method. A web for adsorption comprising.

<Adsorption rate evaluation test>
The adsorption sheets of the examples and comparative examples were evaluated for the adsorption rate of the adsorption sheets by the method described.
The adsorption sheets prepared in Examples and Comparative Examples were dried at a temperature of 90 ° C. for 2 hours, and the mass at that time was regarded as the absolutely dry mass W ₃ . The dried adsorption sheet was allowed to stand in an environmental chamber set at a temperature of 25 ° C. and a relative humidity of 80%, and the mass was measured every 30 seconds. The mass was measured at the time elapsed after standing 60 seconds was W _4.

The adsorption rate of adsorbed moisture of the adsorption sheet was obtained from the following formula.
Adsorption rate A (%) = (W ₄ −W ₃ ) / W ₃ / (W _A / 100) × 100

  The adsorption rate of each adsorption sheet in the examples and comparative examples is shown in Table 3 as follows, compared with the adsorption web not including the thermal conductor in each of the above production methods.

A: Adsorption rate improvement after 60 seconds is 10% or more B: Adsorption rate improvement after 60 seconds is 5% or more and less than 10% Δ: Adsorption rate improvement after 60 seconds is 2% or more to less than 5% X: Adsorption rate improvement after 60 seconds is less than 2%

  From Examples 1 to 6 and Comparative Examples 1 and 2, the adsorption / desorption efficiency was improved depending on the content when the content of the heat conductor was 1 to 20% by mass. From Example 2 and Comparative Example 1, when the content of the heat conductor is less than 1% by mass, the contribution to improving the thermal conductivity of the adsorption sheet is small, and the improvement in adsorption / desorption efficiency is slight. From Comparative Example 2, when the content of the heat conductor exceeds 20% by mass, the respiration of the adsorbing sheet is suppressed by the influence of excessive heat conductor and binder contained in the surface layer of the adsorbing sheet, and the adsorption / desorption efficiency. The improvement is minor.

  Further, the adsorption sheet (Example 1) produced by the method (I) or the adsorption sheet produced by the method (II) (Example 8) rather than the adsorption sheet produced by the method (III) (Example 8) It was shown that Example 7) is more effective in improving the desorption rate and adsorption rate. This is because the adsorbent and the heat conductor are more densely arranged on the surface of the adsorbing sheet in the adsorbing sheet manufactured by the method (I) or (II), and the contact between the air as the contact layer and the heat conductor This is thought to be because the area became wider and showed a high effect in absorbing and releasing heat with air.

  From the results of Examples 1 and 8 to 15, it was confirmed that when the content of the adsorbent is 30 to 80% by mass, the desorption rate and the adsorption rate are easily improved. The desorption rate is improved because the heating penetrates the adsorbent more easily through the heat conductor, and the adsorption rate is improved because of the stagnation caused by the drying of the adsorption sheet and the heat of adsorption through the heat conductor. This is thought to be because heat is easily dissipated. When the content of the adsorbent was less than 30% by mass, it was confirmed that the adsorbent was widely distributed in the sheet and the heat absorption / release was relatively easy, so that the effect of the heat conductor was difficult to be obtained. When the content of the adsorbent exceeds 80% by mass (Example 15), the amount of heat conductor that can be supported is relatively reduced. It was difficult to improve conductivity, and the effect of the heat conductor was difficult to be exhibited as compared with the case where the adsorbent content was 80% by mass (Example 13). Moreover, since the organic fiber contained was small, the mechanical strength of the sheet was also reduced.

  From the comparison of Example 1 and Examples 16 to 19, it was confirmed that the greater the thermal conductivity of the heat conductor, the easier the desorption rate and adsorption rate are improved. Moreover, in the adsorption sheet of Comparative Examples 3 to 7 using a thermal conductor having a thermal conductivity of less than 10 W / m · K, no improvement in the adsorption / desorption rate was observed.

  Comparison of Examples 1, 20 to 23 showed that the moisture absorption / release property of the adsorbing sheet was improved by the inclusion of the heat conductor regardless of the adsorbent conditions used.

  From the above, the adsorption sheet containing organic fibers greatly improves the adsorption and desorption performance by improving the thermal conductivity with a thermal conductor having a thermal conductivity of 10 W / m · K or more. It was confirmed that it can be made.

  The adsorption sheet of the present invention can be used as a dehumidifying filter material, as well as a packaging material, a dehumidifying sheet for indentation and chiffon, and interior materials such as wallpaper and flooring. Moreover, as a filter material for dehumidification, it can be used as a humidity control element or a heat exchange element, for example. Specific examples of humidity control elements and heat exchange elements include building air conditioning vaporization type humidification elements, fuel cell humidification elements, dehumidifier dehumidification elements, water absorption transpiration elements such as vending machines, water absorption transpiration elements for cooling, desiccant air conditioners And a dehumidifying rotor, a total heat exchange element, and the like.

Claims (4)

  It contains at least an organic fiber, an adsorbent, and a thermal conductor having a thermal conductivity of 10 W / m · K or more, and the content of the thermal conductor having a thermal conductivity of 10 W / m · K or more is 1 to 1 per mass of the sheet for adsorption. An adsorption sheet, characterized by being 20% by mass.   2. A web comprising an organic fiber and an adsorbent is manufactured by impregnating or coating a coating liquid containing a thermal conductor having a thermal conductivity of 10 W / m · K or more. The sheet for adsorption as described.   2. A web comprising organic fibers is produced by impregnating or coating a coating liquid containing an adsorbent and a thermal conductor having a thermal conductivity of 10 W / m · K or more. The sheet for adsorption as described.   The adsorbing sheet according to claim 1, wherein the adsorbing sheet is manufactured by producing a web containing an organic fiber, an adsorbent, and a heat conductor having a thermal conductivity of 10 W / m · K or more.