JP2002159828A - Moisture absorbing and desorbing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a moisture absorbing and desorbing material excellent in both of saturated moisture absorbing quantity and a moisture absorbing and desorbing speed and having moisture absorbing and desorbing capacity capable of sufficiently corresponding not only to long-term fluctuations of moisture in environment air but also to short-term fluctuations thereof. SOLUTION: The moisture absorbing and desorbing material contains a water absorbable substance 22 and a moisture absorbable substance 23. For example, the moisture absorbing and desorbing material is constituted by providing a moisture absorbing and desorbing resin layer 2, wherein the water absorbable substance 22 such as a highly water absorbable polymer or the like and the moisture absorbable substance 23 such as an inorganic powder or the like are mixed with and dispersed in a substrate resin 21, on a base material. A foamed moisture permeable protective layer 4 is provided on the moisture absorbing and desorbing resin layer 2 and a pattern printing layer 5 or an embossed pattern 6 can be applied to the protective layer 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention absorbs moisture in environmental air at high humidity, and disperses the absorbed moisture into environmental air at low humidity, thereby mitigating fluctuations in humidity in environmental air. The present invention relates to a moisture-absorbing and desorbing material having a function of performing, and is particularly useful as an interior material of a building.

[0002]

2. Description of the Related Art Modern buildings are compared with the former pure Japanese architecture due to the spread of reinforced concrete structures and prefabricated construction methods, the development of new building materials made of synthetic materials such as resin-processed plywood, and the development of metal sashes on doors and windows. It is extremely airtight. The high airtightness of such a building can be said to be very desirable from the viewpoint of saving energy resources by improving the cooling and heating effect, and preventing noise pollution in the vicinity by improving soundproofing. However, on the other hand, the moisture generated by the resident's living activities (human breath, cooking, bath / shower, etc.) in the room is not easily escaped to the outside and is easily trapped in the room. Condensation on the surface of glass, window frame sash, etc. is not only undesirable from the viewpoint of aesthetics and tactile sensation, but also causes soiling and corrosion of building materials and may shorten the life of the building. is there.

As a solution to this problem, a method of installing a forced-ventilation device or an air-conditioning device in a building to keep the indoor humidity within a certain range has been studied in part. In order to apply forced ventilation or air conditioning to the entire interior of the building, including corridors and storage spaces, the initial capital investment burden becomes extremely heavy, and equipment must be installed at night and when going out. It is not considered to be a very practical method for ordinary households because operating the unit for a long time causes a heavy burden on electricity and requires labor and cost for equipment maintenance.

Therefore, as a method of adjusting the indoor humidity without using the special equipment as described above, the moisture in the environmental air is absorbed at high humidity, while the absorbed moisture is absorbed into environmental air at low humidity. A method has been devised in which a moisture absorbing / releasing material having a function of dissipating is installed in a room to reduce the humidity fluctuation in the room. There are various possible modes for installing the moisture absorbing and releasing material. However, in order to quickly and sufficiently exhibit the moisture absorbing and releasing function, it is considered that a larger surface area in contact with environmental air is more advantageous. A method of finishing a wall surface, a ceiling surface, or the like that occupies a large surface area in a room of an object with an interior material such as a wallpaper using a moisture-absorbing / desorbing material is most promising.

As a wallpaper using the above-mentioned moisture absorbing / releasing material, specifically, for example, a normal wallpaper in which a foamed resin layer such as a polyvinyl chloride resin is provided on a backing paper such as a flame retardant paper,
In order to provide moisture absorption / release properties, a foamed resin layer containing, for example, a hygroscopic inorganic powder such as silica gel or zeolite, or a foamed resin layer containing, for example, a highly water-absorbing polymer such as an acrylic resin or a polyvinyl alcohol-based resin. Compounds and the like have been devised. However, those using the hygroscopic inorganic powder have a high rate of moisture absorption and desorption at the time of humidity fluctuation, but have a small absolute amount of moisture absorption, and are immediately saturated or dried. There is a problem that the ability to alleviate humidity fluctuations is not always sufficient. On the other hand, those using a superabsorbent polymer are advantageous in terms of the ability to absorb and release a large amount of water in the long term because the absolute amount of water absorption is large. Since the humidity rate is low, when the humidity in the environmental air fluctuates greatly in a short time, there is a problem that it is not possible to sufficiently follow the humidity.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and has as its object to address both the saturated moisture absorption and the moisture absorption / desorption rate. An object of the present invention is to provide a moisture-absorbing and desorbing material having excellent moisture-absorbing and desorbing properties, which is excellent and can sufficiently cope with both long-term and short-term fluctuations in humidity in environmental air.

[0007]

The moisture-absorbing and desorbing material of the present invention is characterized by containing a water-absorbing substance and a moisture-absorbing substance. It is characterized by comprising at least a moisture absorbing / releasing resin layer containing a substance.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an embodiment of the moisture-absorbing and releasing material of the present invention.

As an example of the moisture absorbing / releasing material of the present invention,
As shown in FIG. 1, a water-absorbing substance 22 such as a superabsorbent polymer and a hygroscopic substance 23 such as a hygroscopic inorganic powder are placed on the surface of a suitable base material 1 serving as a support in a substrate resin 21. And a moisture absorbing / releasing resin layer 2 made of a resin composition mixed and dispersed in a resin. If necessary, a moisture-permeable protective layer 4 may be provided on the moisture-absorbing / desorbing resin layer 2 to prevent the moisture-absorbing / desorbing resin layer 2 from sticking, deforming, scratching, etc. when absorbing moisture.

The hygroscopic material of the present invention is not limited to the form in which the water absorbing substance 22 and the hygroscopic substance 23 are mixed and dispersed in the resin as described above.
Utilization in the form of being mixed and dispersed inside fibrous materials such as woven fabric, nonwoven fabric, tatami mats, fiberboard, and inorganic materials such as gypsum and concrete or carried on the surface is also conceivable. Even if it does, the principle of the present invention does not change, so the embodiment shown in FIG. 1 will be described below for simplicity.

The specific material and shape of the substrate 1 in the moisture-absorbing and desorbing material of the present invention are not limited at all. For example, a fibrous sheet such as paper, woven or nonwoven fabric, a polyolefin resin sheet, Synthetic resin sheet such as polyester resin sheet, synthetic rubber sheet, acrylic resin plate, polycarbonate resin plate, ABS resin plate, synthetic resin base material such as FRP, plywood, laminated wood, fiber board, wood board such as particle board Any material can be used, such as materials, metal base materials such as steel plates, brass plates, and aluminum plates, and inorganic base materials such as gypsum plates, calcium silicate plates, cement plates, and concrete plates. If necessary, an appropriate surface treatment such as a plugging treatment, a base coat treatment, a primer treatment, a corona discharge treatment, an ozone treatment, a flame treatment, a polishing treatment, or the like is applied. It may be.

In particular, when the moisture-absorbing and desorbing material of the present invention is used as wallpaper, any sheet-like material conventionally used as a base material of a synthetic resin-based wallpaper can be used. Specifically, for example, pulp paper-based flame-retardant paper in which a water-soluble flame retardant such as guanazine sulfanilate or guanazine phosphate is impregnated into paper-made paper made of cellulosic fibers such as wood pulp, Flame-retardant or non-flammable paper, such as inorganic mixed paper mixed with an inorganic agent such as calcium, aluminum hydroxide or magnesium hydroxide, inorganic fiber paper formed from inorganic fibers such as glass fiber or alumina fiber, or flame retardant or inorganic Flame-retardant or non-flammable woven or non-woven fabrics made by adding agents or manufactured from inorganic fibers,
Either can be used.

The moisture absorbing / releasing resin layer 2 in the moisture absorbing / releasing material of the present invention is formed by mixing and dispersing a water absorbing substance 22 and a moisture absorbing substance 23 in a base resin 21. As the substrate resin 21, any resin may be used as long as it has a film-forming property, has a low water-swelling swelling property, and can maintain the shape of the film even when the water-absorbing substance 22 absorbs and swells. In order not to hinder the absorption or release of moisture between the water-absorbing substance 22 and the hygroscopic substance 23 in the ambient air,
For example, acrylic resins, urethane resins, SBR resins, vinyl acetate resins, ethylene-vinyl acetate copolymer resins, silicone resins, polyamide resins, polybutene resins, and polyvinyl alcohol resins have high moisture permeability. It is preferable to use a resin, and any one of them may be used alone, or a mixture of two or more resins may be used.

The water-absorbing substance 22 added to the moisture-absorbing / releasing resin layer 2 is a substance having a relatively sparse structure containing many hydrophilic functional groups such as hydroxyl groups and carboxyl groups, and exceeding its own volume. Any substance capable of absorbing and storing a large amount of water therein may be used. Specifically, a known general super-absorbent polymer or the like is used. For example, starch-acrylic acid graft polymer, starch-acrylonitrile graft polymer And cellulose-acrylonitrile graft polymer, polyvinyl alcohol cross-linked polymer, sodium polyacrylate cross-linked product, saponified methyl acrylate-vinyl acetate copolymer and the like. It is also possible to use natural products such as potato starch and dextrins, and these water-absorbing substances can be used alone or in combination of two or more.

As the hygroscopic substance 23 added to the hygroscopic resin layer 2, particles of a porous hydrophilic inorganic substance having a large specific surface area capable of adsorbing and holding a large amount of water molecules on the surface thereof are suitable. Specifically, for example, a powder of silica gel, zeolite, diatomaceous earth, calcined talc, or the like can be suitably used.

As described above, the moisture-absorbing / desorbing material of the present invention contains the water-absorbing substance 22 and the moisture-absorbing substance 23, so that when the high humidity state continues for a long time,
By the action of the water-absorbing substance 22 having a large saturated water absorption, a large amount of water is absorbed and accumulated. Conversely, if the low humidity state continues for a long time, a large amount of water that has been absorbed and accumulated is released. In addition to the effect of mitigating long-term fluctuations in humidity, when the humidity fluctuates significantly in the environmental air in a short period of time, the action of the hygroscopic substance 23 having a large moisture absorption / desorption rate causes a large amount of the water to be absorbed in a short period of time. Since water can be absorbed or released, the effect of alleviating short-term fluctuations in humidity can be sufficiently achieved.

The short-term effect described above is not only because the hygroscopic substance 23 absorbs and releases moisture alone, but also because the hygroscopic substance 23 promotes the absorption and release of water by the water absorbing substance 22.
It was revealed that the hygroscopic substance 23 exhibited much greater moisture absorption / desorption performance than when used alone. The reason is that the water-absorbing substance 22 such as a superabsorbent polymer only absorbs moisture spontaneously condensed around it,
When the humidity rises, the hygroscopic substance actively condenses gaseous water molecules and transfers it to the water absorbent substance 22, while
Conversely, it is presumed that when the humidity decreases, the water-absorbing substance 22 has a function of receiving the moisture held therein and evaporating it.

The mixing ratio of the water-absorbing substance 22 and the hygroscopic substance 23 is not particularly limited in the present invention.
Since the amount of water absorbed by the hygroscopic substance 23 itself is smaller than that of the water absorbent substance 22, if a larger amount of the hygroscopic substance 23 is blended than the water absorbent substance 22, the saturated water absorption is small in the long term but short term. The rate of moisture absorption and desorption at high humidity changes is high, and conversely, if more water-absorbing substance 22 is blended than moisture-absorbing substance 23, sensitivity to short-term humidity fluctuation decreases, but long-term saturated water absorption becomes Since it increases, it may be appropriately designed according to the purpose of use. Generally, the hygroscopic substance 23 is the water absorbent substance 2
In the catalytic sense of 2, a smaller amount may be used than the water-absorbing substance 22,
100 parts by weight of water-absorbing substance 22 and hygroscopic substance 23
Is desirably blended in an amount of about 30 to 100 parts by weight.

The substrate resin 21 in the moisture absorbing / releasing resin layer 2
The blending ratio of the water-absorbing substance 22 and the hygroscopic substance 23 is not particularly limited in the present invention, but generally the base resin 21 is 20 to 80% by weight, and the water-absorbing substance 22 and the hygroscopic substance 23 are It is desirable that the total be about 80 to 20% by weight. When the content of the substrate resin 21 is less than 20% by weight, it is difficult to sufficiently suppress the significant deformation and decrease in strength due to water absorption and swelling of the water-absorbing substance 22 at high humidity. If it exceeds 80% by weight, it is difficult to obtain a sufficient moisture absorbing / releasing function. The thickness of the moisture-absorbing / desorbing resin layer 2 is not particularly limited in the present invention. However, in consideration of the expression of a sufficient moisture-absorbing / desorbing function, workability in manufacturing, flexibility in handling, and the like, Generally 10 to 10
It is desirable to set it within the range of about 0 μm.

The surface of the moisture-absorbing / desorbing resin layer 2 is prevented from sticking to the surface of the moisture-absorbing substance 22 in the moisture-absorbing / desorbing resin layer 2 at the time of high humidity or wetness due to water absorption and swelling, and a decrease in surface strength. For this reason, the moisture-permeable protective layer 4 having a moisture-permeable property that does not impair the moisture-absorbing / desorbing function of the moisture-absorbing / releasing resin layer 2 can be provided. The material of the moisture-permeable protective layer 4 is required to be a hydrophilic resin composition capable of forming a film having high moisture permeability, and more specifically, the form of an aqueous coating solution such as an aqueous solution or an aqueous dispersion. It is preferable to use an aqueous resin 41 that can form a water-insoluble and water-resistant coating while being hydrophilic after coating and drying, and is made of the same or different materials. A stacked structure of more than two layers may be used.

Aqueous resin 4 which is a main component of moisture-permeable protective layer 4
Specifically, as 1, for example, a water-soluble salt type acrylic resin,
Addition or ionization of water-soluble resins such as polyacrylamide, polyvinyl alcohol, polyvinylpyrrolidone, casein, cellulose derivatives, dextrins, etc. What has been made insoluble by crosslinking by means of irradiation or the like, for example, acrylic resin, polyurethane resin, SBR resin, vinyl acetate resin, ethylene vinyl acetate copolymer resin, silicone resin, polybutene resin, etc. At least one or a mixture of two or more resins such as an aqueous emulsion resin obtained by dispersing water-insoluble resin particles in water can be used. It is desirable to use an aqueous emulsion resin in terms of the stability of the coating liquid, the surface properties after coating and drying, and the high moisture permeability due to the microporous state. Needless to say, the aqueous emulsion resin may be crosslinked by blending a crosslinking agent or irradiating with ionizing radiation.

If necessary, the moisture-permeable protective layer 4 may be foamed into porous cells by a known appropriate means such as a mechanical foaming method or a method of incorporating a foaming agent 42. , Further improving the moisture permeability of the moisture-permeable protective layer 4,
The moisture absorbing / releasing function of the moisture absorbing / releasing resin layer 2 can be further exerted. When the moisture-absorbing / desorbing material of the present invention is used as an interior material such as a wallpaper in a building such as a house, the unevenness pattern 6 is easily formed by embossing by foaming the moisture-permeable protective layer 4. There is also an advantage that an interior material having excellent properties can be easily obtained.

Examples of the foaming agent 42 include azo compounds such as azodicarbonamide (ADCA), and P and P '.
-Oxybis (benzenesulfonyl hydrazide) (O
A thermal decomposition chemical blowing agent such as an organic blowing agent such as a nitroso compound such as BSH) or an inorganic blowing agent such as sodium hydrogen carbonate;
For example, polyacrylonitrile resin, phenol resin,
An expandable microcapsule foaming agent containing a low-boiling liquid such as isobutane in a heat-softening flexible shell such as an epoxy resin can be used.

The amount of the foaming agent 42 is not particularly limited in the present invention, but is generally based on 100 parts by weight of the solid content of the aqueous resin 41 as a main component of the moisture-permeable protective layer 4. It is preferable to add 2 to 20 parts by weight,
More preferably, it is 4 to 10 parts. If the amount is less than 2 parts by weight, the foaming ratio is low and the effect of improving the moisture absorption / release properties cannot be expected much, and it is also difficult to improve the design property by the embossed uneven pattern 6. On the other hand, if it is more than 20 parts by weight,
There is a possibility that the foam cells become extremely coarse and the surface strength of the sheet becomes weak.

The moisture-permeable protective layer 4 may further include an inorganic filler such as calcium carbonate, barium sulfate, aluminum hydroxide, or magnesium hydroxide, if necessary.
Starting with coloring pigments such as titanium oxide and zinc oxide, dispersants, defoamers, wetting agents, flame retardants, flame retardants, antibacterial agents, fungicides, ultraviolet absorbers, light stabilizers, heat stabilizers, lubricants, One or more selected from various additives such as a gloss adjusting agent, an antistatic agent, an antiblocking agent, and a thickener can also be appropriately added.

The thickness of the moisture-permeable protective layer 4 is not particularly limited in the present invention. Since the moisture absorbing / releasing function of the moisture absorbing / releasing resin layer 2 is reduced, it is necessary to appropriately design in consideration of these. In general, the thickness is preferably in the range of about 5 to 100 μm when non-foamed and about 20 to 2000 μm when foamed.

The main component of the moisture-permeable protective layer 4 is as described above.
It is desirable to use an aqueous resin 41 that is applied using an aqueous coating liquid such as an aqueous solution or an aqueous dispersion, but the aqueous resin is directly applied to the surface of the moisture absorbing / releasing resin layer 2 containing the water absorbing substance 22. When the working liquid is applied, the water contained in the water-based coating liquid is absorbed by the water-absorbing substance in the moisture-absorbing / desorbable resin layer 2 during the coating, and a good coating state cannot be obtained. There are cases. In such a case, before the application of the aqueous coating solution for forming the moisture-permeable protective layer 4, the moisture-absorbing and desorbing resin layer 2 and the ambient air are placed on the surface of the moisture-absorbing and desorbing resin layer 2. And moisture absorption and desorption of water in the aqueous coating solution when the aqueous coating solution for forming the moisture-permeable protective layer 4 is applied. By providing a moisture-permeable waterproof resin coating 3 made of a hydrophilic and water-resistant resin composition having a waterproof property that can prevent penetration into the resin layer 2,
Can be dealt with effectively.

The composition of the resin composition constituting the moisture-permeable waterproof resin film 3 is not particularly limited in the present invention.
Acrylic resin, urethane resin, SBR resin, vinyl acetate resin, ethylene-vinyl acetate copolymer resin, silicone resin, polyamide resin, polybutene resin similar to those mentioned as examples of the substrate resin 21 , Polyvinyl alcohol resin and the like, and one of these may be used alone, or a mixture or a laminated film of two or more thereof may be used.

If the thickness of the moisture-permeable waterproof resin film 3 is too small, the waterproofness becomes insufficient and the swelling of the water-absorbing substance 22 in the moisture-absorbing / releasing resin layer 2 at the time of coating the moisture-permeable protective layer 4 is sufficient. On the other hand, if the thickness is too large, the moisture permeability will be reduced and the moisture absorption / desorption performance of the moisture absorption / desorption resin layer 2 will be reduced. Therefore, it is necessary to set the thickness appropriately in consideration of both. When the resin composition constituting the moisture-permeable waterproof resin coating 3 is selected from the above-mentioned various resins, for example, the thickness of the moisture-permeable waterproof resin coating 3 is generally in the range of about 0.2 to 20 μm. It is preferred to be within.

The method for forming the moisture-absorbing / desorbing resin layer 2, the moisture-permeable waterproof resin coating 3, and the moisture-permeable protective layer 4 described above is not particularly limited in the present invention. The moisture-permeable waterproof resin film 3 uses an oil-based coating liquid containing a hydrophobic organic solvent as a dispersion medium, and the moisture-permeable protective layer 4 contains an aqueous coating liquid containing water or a mixture of water and alcohols as a dispersion medium. It is common to use a method of sequentially forming them by a coating method. Coating methods include, for example, knife coating, nozzle coating, gravure coating, microgravure coating, rotary screen coating, reverse coating, comma coating, lip coating, die coating, spray coating, and dip coating. Any conventionally known coating method such as a coating method and a flow coating method can be adopted.As a drying method after the coating of each layer, for example, a heat source such as hot air or an infrared heater may be used alone or in combination of a plurality thereof. They can be used in combination.

The moisture-absorbing and desorbing material of the present invention may be
A design printing layer 5 may be provided on the surface of the moisture-permeable protective layer 4 to provide a design with a design. As a printing method of the picture printing layer 5, a normal printing method such as a gravure printing method, a rotary screen printing method, a flexographic printing method, an ink jet printing method, a transfer printing method, or the like can be used. In addition, in order to provide a three-dimensional design, or to provide the uneven pattern 6 processing by a mechanical embossing method or a chemical embossing method, or to further improve the surface strength,
It is also possible to arbitrarily provide a surface protective layer made of a moisture-permeable resin composition on the surface.

[0032]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples.

Example 1 A hygroscopic resin composition having the following composition was first applied on a surface of an inorganic paper having a basis weight of 90 g / m ² by a comma coat method and dried at about 90 ° C. Then, a moisture-absorbing / releasing resin layer having a coating amount of about 20 g / m ² after drying was provided. Subsequently, about 1 g of a solvent-based urethane resin was dried on the moisture-absorbing and desorbing resin layer by a gravure coating method.
/ M ² and dried to form a moisture-permeable waterproof resin film,
Further, on the moisture-permeable waterproof resin film, an ethylene-vinyl acetate copolymer-based aqueous emulsion resin containing a microcapsule foaming agent in a solid content ratio of 6 parts by weight was applied by a comma coat method to a coating amount of about 140 g / m ² after drying. Then, the resultant was dried at about 90 ° C. to form a moisture-permeable protective layer. After printing an abstract pattern on the surface of the moisture-permeable protective layer by gravure printing, the moisture-permeable protective layer is foamed about 5 times in a foaming heating furnace at a furnace temperature of about 150 ° C., and then foamed. An embossed pattern was formed on the surface of the moisture-permeable protective layer using a cooling embossing roll, to produce a wallpaper as the moisture-absorbing and releasing material of the present invention. The obtained wallpaper has no defects such as coating unevenness of each layer,
It had good appearance in appearance.

[Blending Table of Hygroscopic Resin Composition] Water-absorbing substance Urethane-based superabsorbent polymer 40 parts by weight Hygroscopic substance Colloidal synthetic silica 30 parts by weight Base resin polyurethane 90 parts by weight

<Comparative Example 1> In Example 1, the hygroscopic substance was not added to the moisture-absorbing / releasing resin composition, the amount of the water-absorbing substance was 70 parts by weight, and the others were exactly the same as in Example 1 above. Under the conditions described above, a wallpaper as a moisture absorbing / releasing material was produced.

<Comparative Example 2> In Example 1, no water-absorbing substance was added to the moisture-absorbing / releasing resin composition, and the amount of the hygroscopic substance was 70 parts by weight. Under the conditions described above, a wallpaper as a moisture absorbing / releasing material was produced.

<Comparison of Performance> The above Example 1 and Comparative Examples 1 to
Regarding the wallpaper of No. 2, a commercially available vinyl chloride-based dew-prevention wallpaper (a backing paper provided with a polyvinyl chloride resin foam layer to which a superabsorbent polymer is added) and a commercially available normal non-dew-prevention-processed wallpaper As a result of measuring the moisture absorption / desorption performance by the following test method together with a vinyl chloride-based wallpaper (a foamed layer of a polyvinyl chloride resin to which a superabsorbent polymer was not added on a backing paper), the absorption of the present invention was measured. As shown in FIG. 2, it was confirmed that the wallpaper of Example 1, which is a moisture-releasing material, had very excellent moisture-absorbing and releasing performance.

<Moisture absorption / desorption performance test method>
The sheet is cut into a size of 7 cm, and a small edge of 1 cm square on the front surface and the entire back surface are covered with an aluminum tape, and a treatment for preventing moisture permeation from the side surface and the back surface is performed. From the above treatment, the moisture permeable surface area of the sample is set to 100 cm ^{2 of} 4 cm × 25 cm. The test piece thus prepared was allowed to stand in a thermo-hygrostat set at a temperature of 25 ° C. and a relative humidity of 50% for 4 days, and then the weight (a) of the test piece was measured and used as an initial value. . next,
The test piece was left for 144 hours in a thermo-hygrostat set at a temperature of 25 ° C. and a relative humidity of 90%.
1 ℃ in a constant temperature and high humidity tester set at 50 ° C and 50% relative humidity
The specimen is left for 44 hours, during which time the weight (b) of the test piece is measured at appropriate time intervals. The moisture absorption of the test piece at each time is calculated by the following equation (1). Moisture absorption [g / m ² ] = (test piece weight (b) [g] −test piece weight (a) [g]) / moisture permeable surface area [m ² ] (1)

[0039]

As described in detail above, the moisture-absorbing and desorbing material of the present invention contains a water-absorbing substance and a hygroscopic substance, and thus, by the action of the water-absorbing substance having a large saturated water absorption,
Even if a high humidity state or a low humidity state continues for a long time, a large amount of water can be absorbed and stored or released and evaporated,
Excellent long-term humidity adjustment effect, and even when the humidity in the environmental air fluctuates rapidly in a short period of time, the action of the hygroscopic substance to promote the absorption and desorption of water-absorbing substances with a low moisture absorption and desorption rate Accordingly, a large amount of water can be absorbed and stored or released and evaporated in a short time, so that the present invention is also excellent in a humidity adjustment effect against short-term humidity fluctuation.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a moisture-absorbing and releasing material of the present invention.

FIG. 2 is a graph showing the results of a moisture absorption / release performance test of an example of the moisture absorption / release material of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Hygroscopic resin layer 21 ... Substrate resin 22 ... Water absorbing substance 23 ... Hygroscopic substance 3 ... Moisture-permeable waterproof resin film 4 ... Moisture-permeable protective layer 41 ... Water-based resin 42 ... Foaming agent 5 ... Pattern printing layer 6 ... Uneven pattern

Continuation of the front page (72) Inventor Hiroshi Yagabe 1-5-1, Taito, Taito-ku, Tokyo Letterpress Printing Co., Ltd. F-term (reference) 2E001 DB03 FA10 GA03 GA24 GA27 GA28 HA01 HA03 HA04 HA21 HB02 HB04 HC02 HC04 HD11 HE01 JA00 JA06 JA22 JC02 JC03 JD02 4D052 AA00 CA02 GA01 GB03 HA01 HA27 HA35 HB06 4F100 AA20H AK01B AK51 AK51H AK68 AT00A BA02 BA05 CA30B DG10 DJ01 GB08 HB21 HB31 JD15B JD15H JD16BJD

Claims (2)

[Claims] 1. A moisture-absorbing / desorbing material comprising a water-absorbing substance and a moisture-absorbing substance. 2. The hygroscopic material according to claim 1, further comprising a hygroscopic resin layer containing a water-absorbing substance and a hygroscopic substance on the substrate.