HUMIDITY CONDITIONING MATERIAL AND PRODUCTION METHOD THEREOF

Abstract

Provided are a humidity conditioning material that adsorbs and desorbs a large amount of moisture, and a production method thereof.

A humidity conditioning material comprising: a porous silica material having an average pore diameter of 1 nm or more; and a carrier, wherein the humidity conditioning material contains an alkali metal element in an amount of 0.001 wt % or more and less than 1.0 wt %.

A method for producing a humidity conditioning material involving the following Step (1), Step (2), and Step (3).

Step (1): A dispersion medium is mixed with a porous silica material having an average pore diameter of 1 nm or more to obtain a slurry, and an amount of alkali metal element in the slurry is adjusted to be 0.001 wt % to 1 wt % relative to a solid content weight therein.

Step (2): The slurry obtained in Step (1) is applied to a carrier.

Step (3): The dispersion medium is removed from the carrier coated with the slurry obtained in Step (2) to yield a humidity conditioning material containing the porous silica material and the carrier.

Claims

1. A humidity conditioning material comprising: a porous silica material having an average pore diameter of 1 nm or more; and a carrier, wherein the humidity conditioning material comprises an alkali metal element in an amount of 0.001 wt % or more and less than 1.0 wt %.

2. The humidity conditioning material according to claim 1, further comprising an inorganic binder, wherein the inorganic binder has an average particle diameter at least twice the average pore diameter of the porous silica material.

3. The humidity conditioning material according to claim 1, further comprising a water-soluble polymer.

4. The humidity conditioning material according to claim 1, wherein the carrier contains an inorganic fiber.

5. The humidity conditioning material according to claim 1, wherein the alkali metal element is sodium and/or potassium.

6. The humidity conditioning material according to claim 1, wherein the porous silica material has an average pore diameter of 1.0 to 3.0 nm.

7. The humidity conditioning material according to claim 1, wherein the humidity conditioning material contains the alkali metal element in an amount of 0.006 to 0.8 wt %.

8. The humidity conditioning material according to claim 2, wherein the inorganic binder has an average particle diameter 2.0 times or more and 15 times or less the average pore diameter of the porous silica material.

9. The humidity conditioning material according to claim 2, wherein the inorganic binder has an average particle diameter of 15 nm or less.

10. A method for producing a humidity conditioning material, the method comprising the following: Step (1): a dispersion medium is mixed with a porous silica material having an average pore diameter of 1 nm or more to obtain a slurry, and an amount of alkali metal element in the slurry is adjusted to be 0.001 wt % to 1 wt % relative to a solid content weight therein; Step (2): the slurry obtained in Step (1) is applied to a carrier; and Step (3): the dispersion medium is removed from the carrier coated with the slurry obtained in Step (2) to yield a humidity conditioning material containing the porous silica material and the carrier.

11. The method for producing a humidity conditioning material according to claim 10, the method further comprising Step (4): the humidity conditioning material yielded in Step (3) is heated at a temperature of 300 degrees C. or higher.

Description

EXAMPLES

[0202] Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to the following Examples.

Example 1

Production and Evaluation of Humidity Conditioning Material 1

[0203] <Production of Porous Silica Material>

[0204] First step: While 625.5 g of 16 wt % of hexadecyltrimethylammonium hydroxide aqueous solution was stirred, a mixed aqueous solution containing 9.25 g of tetraisopropyl titanate and 50.0 g of 2-propanol was dropped into the solution at room temperature. The resulting mixture was stirred for 30 minutes, and then, 190.5 g of tetramethyl orthosilicate was dropped into the mixture. To the mixture, 5.0 g of 2-propanol was added, and the resultant was stirred for 3 hours to obtain a precipitate.

[0205] Second step: The precipitate obtained in the first step was filtered, and the precipitate was washed with 5 liters of ion-exchanged water. The resulting precipitate was dried under reduced pressure at 100 degrees C. for 5 hours to obtain a solid.

[0206] Third step: 20 g of the solid obtained in the second step was added to a flask, and then, a mixed aqueous solution containing 200 ml of methanol and 10 g of concentrated hydrochloric acid (36 wt %) was added to the solution. The resulting mixture was stirred and heated at reflux temperature for 1 hour. The resultant was allowed to cool, and then, the aqueous solution was removed by filtration to obtain a solid. A similar operation was repeated for the obtained solid using a mixed aqueous solution containing 200 ml of methanol and 5 g of concentrated hydrochloric acid. The resulting solid was refluxed with 200 ml of methanol for 1 hour, and then, 10 mmHg of the filtered solid was dried under reduced pressure at 120 degrees C. for 1.5 hours to obtain a solid.

[0207] The solid obtained in the third step was heated at 600 degrees C. for 3 hours under air flow to obtain a porous silica material.

[0208] The porous silica material obtained was pulverized eight times with a hammer mill to obtain a powdery porous silica material having an average particle diameter of 10 μm. The average particle diameter was determined by the aforementioned method using the laser diffraction particle size analyzer.

[0209] The powdery porous silica material obtained had a specific surface area of 1160 m.sup.2/g, a total pore volume of 0.60 cc/g, and an average pore diameter of 2.2 nm. The specific surface area, total pore volume, and average pore diameter of the porous silica material were determined by the aforementioned method after the porous silica material was subjected to vacuum degassing at 120 degrees C. for 2 hours.

[0210] <Production of Slurry>

[0211] In 29 g of ion-exchanged water, 0.4 g of sodium alginate 500-600 (Wako Pure Chemical Industries, Ltd.) serving as a water-soluble polymer was dissolved. To the resultant, 4.0 g of the aforementioned powdery porous silica material was added and mixed to obtain 33.4 g of a slurry (1). The pH of the slurry (1) was about 6. An amount of alkali metal element relative to a solid content weight of the slurry (1) was 1.1 wt %.

[0212] <Production of Humidity Conditioning Material>

[0213] A glass fiber sheet (1.5 cm×5 cm×0.24 mm) serving as a carrier was immersed in 33.2 g of the slurry (1) and allowed to stand for 1 minute, and then, the sheet was removed from the slurry (1). The sheet obtained was blown with a dryer until the slurry stopped dropping, and then, dried at 140 degrees C. for 2 hours to yield a humidity conditioning material 1. The humidity conditioning material 1 contained the alkali metal element in an amount of 0.45 wt %. Table 1 shows the results.

[0214] <Evaluation of Amount of Moisture Absorbed>

[0215] The humidity conditioning material 1 was stored for 30 minutes or more in an auto dry desiccator set at room temperature and relative humidity of 0%. A weight of the humidity conditioning material 1 after water desorption (the weight is referred to as “weight 1”) was measured. Next, the humidity conditioning material 1 was stored for 30 minutes in a constant temperature and humidity bath set at 25 degrees C. and relative humidity of 70%. A weight of the humidity conditioning material 1 after water adsorption (the weight is referred to as “weight 2) was measured. An amount of moisture absorbed obtained by subtracting the weight 1 from the weight 2 was divided by the weight 1 to calculate a weight fraction (unit: wt %) of the amount of moisture absorbed with respect to the humidity conditioning material. The amount of moisture absorbed in the humidity conditioning material 1 was 20 wt %. Table 1 shows the results.

Example 2

Production and Evaluation of Humidity Conditioning Material 2

[0216] <Production of Porous Silica Material>

[0217] The powdery porous silica material obtained in Example 1 was used.

[0218] <Production of Slurry>

[0219] In 29.0 g of ion-exchanged water, 0.2 g of sodium alginate 500-600 (Wako Pure Chemical Industries, Ltd.) serving as a water-soluble polymer and 0.06 g of sodium acetate were dissolved. To the resultant, 4.0 g of the porous silica material was added and mixed to obtain 33.3 g of a slurry (2). The pH of the slurry (2) was about 7. An amount of alkali metal element relative to a solid content weight of the slurry (2) was 0.97 wt %

[0220] <Production of Humidity Conditioning Material>

[0221] A humidity conditioning material 2 was yielded in a similar manner to Example 1 except that the slurry (2) was used. The humidity conditioning material 2 contained the alkali metal element in an amount of 0.51 wt %. Table 1 shows the results.

[0222] <Evaluation of Amount of Moisture Absorbed>

[0223] An amount of moisture absorbed in the humidity conditioning material 2 was evaluated in a similar manner to Example 1. The amount of moisture absorbed in the humidity conditioning material 2 was 20 wt %. Table 1 shows the results.

Example 3

Production and Evaluation of Humidity Conditioning Material 3

[0224] <Production of Porous Silica Material>

[0225] The powdery porous silica material obtained in Example 1 was used.

[0226] <Production of Slurry>

[0227] In 29.0 g of ion-exchanged water, 0.2 g of sodium alginate 500-600 (Wako Pure Chemical Industries, Ltd.) serving as a water-soluble polymer was dissolved. To the resultant, 4.0 g of the porous silica material was added and mixed to obtain 33.2 g of a slurry (3). The pH of the slurry (3) was about 6. An amount of alkali metal element relative to a solid content weight of the slurry (3) was 0.54 wt %

[0228] <Production of Humidity Conditioning Material>

[0229] A humidity conditioning material 3 was yielded in a similar manner to Example 1 except that the slurry (3) was used, and after drying a sheet for 2 hours at 140 degrees C., the sheet was fired in the atmosphere in a muffle furnace at 600 degrees C. for 3 hours (firing time: 1 hour). The humidity conditioning material 3 contained the alkali metal element in an amount of 0.44 wt %. Table 1 shows the results.

[0230] <Evaluation of Amount of Moisture Absorbed>

[0231] An amount of moisture absorbed in the humidity conditioning material 3 was evaluated in a similar manner to Example 1. The amount of moisture absorbed in the humidity conditioning material 3 was 18 wt %. Table 1 shows the results.

Example 4

Production and Evaluation of Humidity Conditioning Material 4

[0232] <Production of Porous Silica Material>

[0233] The powdery porous silica material obtained in Example 1 was used.

[0234] <Production of Slurry>

[0235] To 25.2 g of ion-exchanged water, added was 4.0 g of silica sol (SNOWTEX ST-N-40 (Nissan Chemical Corporation), average particle diameter: from 20 to 25 nm, concentration of solid content: 40 wt %) serving as a binder. To the resultant, 4.0 g of the porous silica material was added and mixed to obtain 33.2 g of a slurry (4). The pH of the slurry (4) was about 6. An amount of alkali metal element relative to a solid content weight of the slurry (4) was 0.093 wt %

[0236] <Production of Humidity Conditioning Material>

[0237] A humidity conditioning material 4 was yielded in a similar manner to Example 3 except that the slurry (4) was used. The humidity conditioning material 4 contained the alkali metal element in an amount of 0.074 wt %. Table 1 shows the results.

[0238] <Evaluation of Amount of Moisture Absorbed>

[0239] An amount of moisture absorbed in the humidity conditioning material 4 was evaluated in a similar manner to Example 1. The amount of moisture absorbed in the humidity conditioning material 4 was 18 wt %. Table 1 shows the results.

Example 5

Production and Evaluation of Humidity Conditioning Material 5

[0240] <Production of Porous Silica Material>

[0241] The powdery porous silica material obtained in Example 1 was used.

[0242] <Production of Slurry>

[0243] In 28.9 g of ion-exchanged water, 0.4 g of sodium alginate 500-600 (Wako Pure Chemical Industries, Ltd.) serving as a water-soluble polymer was dissolved. To the resultant, 4.0 g of the porous silica material was added and mixed to obtain 33.3 g of a slurry (5). The pH of the slurry (5) was about 6. An amount of alkali metal element relative to a solid content weight of the slurry (5) was 1.1 wt %

[0244] <Production of Humidity Conditioning Material>

[0245] A humidity conditioning material 5 was yielded in a similar manner to Example 3 except that the slurry (5) was used. The humidity conditioning material 5 contained the alkali metal element in an amount of 0.78 wt %. Table 1 shows the results.

[0246] <Evaluation of Amount of Moisture Absorbed>

[0247] An amount of moisture absorbed in the humidity conditioning material 5 was evaluated in a similar manner to Example 1. The amount of moisture absorbed in the humidity conditioning material 5 was 12 wt %. Table 1 shows the results.

Example 6

Production and Evaluation of Humidity Conditioning Material 6

[0248] <Production of Porous Silica Material>

[0249] The powdery porous silica material obtained in Example 1 was used.

[0250] <Production of Slurry>

[0251] In 29.0 g of ion-exchanged water, 0.2 g of METOLOSE 65SH-4000 (Shin-Etsu Chemical Co., Ltd., water-soluble cellulose ether) serving as a water-soluble polymer was dissolved. To the resultant, 4.0 g of the porous silica material was added and mixed to obtain 33.2 g of slurry (6). The pH of the slurry (6) was about 7. An amount of alkali metal element relative to a solid content weight of the slurry (6) was 0.0039 wt %

[0252] <Production of Humidity Conditioning Material>

[0253] A humidity conditioning material 6 was yielded in a similar manner to Example 3 except that the slurry (6) was used. The humidity conditioning material 6 contained the alkali metal element in an amount of 0.005 wt %. Table 1 shows the results.

[0254] <Evaluation of Amount of Moisture Absorbed>

[0255] An amount of moisture absorbed in the humidity conditioning material 6 was evaluated in a similar manner to Example 1. The amount of moisture absorbed in the humidity conditioning material 6 was 18 wt %. Table 1 shows the results.

Example 7

Production and Evaluation of Humidity Conditioning Material 10

[0256] <Production of Porous Silica Material>

[0257] The powdery porous silica material obtained in Example 1 was used.

[0258] <Production of Slurry>

[0259] To 21.2 g of ion-exchanged water, added was 8.0 g of silica sol (SNOWTEX ST-N (Nissan Chemical Corporation), average particle diameter: from 10 to 15 nm, concentration of solid content: 20 wt %) serving as a binder. To the resultant, 4.0 g of the porous silica material was added and mixed to obtain 33.2 g of a slurry (10). The pH of the slurry (10) was about 6. An amount of alkali metal element relative to a solid content weight of the slurry (10) was 0.045 wt %

[0260] <Production of Humidity Conditioning Material>

[0261] A humidity conditioning material 10 was yielded in a similar manner to Example 3 except that the slurry (10) was used. The humidity conditioning material 10 contained the alkali metal element in an amount of 0.026 wt %. Table 1 shows the results.

[0262] <Evaluation of Amount of Moisture Absorbed>

[0263] An amount of moisture absorbed in the humidity conditioning material 10 was evaluated in a similar manner to Example 1. The amount of moisture absorbed in the humidity conditioning material 10 was 26 wt %. Table 1 shows the results.

Example 8

Production and Evaluation of Humidity Conditioning Material 11

[0264] <Production of Porous Silica Material>

[0265] The powdery porous silica material obtained in Example 1 was used.

[0266] <Production of Slurry>

[0267] To 21.2 g of ion-exchanged water, added was 8.0 g of silica sol (SNOWTEX ST-NS (Nissan Chemical Corporation), average particle diameter: from 8 to 11 nm, concentration of solid content: 20 wt %) serving as a binder. To the resultant, 4.0 g of the porous silica material was added and mixed to obtain 33.2 g of a slurry (11). The pH of the slurry (11) was about 6. An amount of alkali metal element relative to a solid content weight of the slurry (11) was 0.031 wt %

[0268] <Production of Humidity Conditioning Material>

[0269] A humidity conditioning material 11 was yielded in a similar manner to Example 3 except that the slurry (11) was used. The humidity conditioning material 11 contained the alkali metal element in an amount of 0.014 wt %. Table 1 shows the results.

[0270] <Evaluation of Amount of Moisture Absorbed>

[0271] An amount of moisture absorbed in the humidity conditioning material 11 was evaluated in a similar manner to Example 1. The amount of moisture absorbed in the humidity conditioning material 11 was 25 wt %. Table 1 shows the results.

Example 9

Production and Evaluation of Humidity Conditioning Material 12

[0272] <Production of Porous Silica Material>

[0273] The powdery porous silica material obtained in Example 1 was used.

[0274] <Production of Slurry>

[0275] To 18.2 g of ion-exchanged water, added was 11.1 g of silica sol (SNOWTEX ST-NSX (Nissan Chemical Corporation), average particle diameter: from 4 to 6 nm, concentration of solid content: 14 wt %) serving as a binder. To the resultant, 4.0 g of the porous silica material was added and mixed to obtain 33.3 g of a slurry (12). The pH of the slurry (12) was about 6. An amount of alkali metal element relative to a solid content weight of the slurry (12) was 0.028 wt %

[0276] <Production of Humidity Conditioning Material>

[0277] A humidity conditioning material 12 was yielded in a similar manner to Example 3 except that the slurry (12) was used. The humidity conditioning material 12 contained the alkali metal element in an amount of 0.016 wt %. Table 1 shows the results.

[0278] <Evaluation of Amount of Moisture Absorbed>

[0279] An amount of moisture absorbed in the humidity conditioning material 12 was evaluated in a similar manner to Example 1. The amount of moisture absorbed in the humidity conditioning material 12 was 27 wt %. Table 1 shows the results.

Comparative Example 1

Production and Evaluation of Humidity Conditioning Material 7

[0280] <Production of Porous Silica Material>

[0281] The powdery porous silica material obtained in Example 1 was used.

[0282] <Production of Slurry>

[0283] In 29.0 g of ion-exchanged water, 0.2 g of sodium alginate 500-600 (Wako Pure Chemical Industries, Ltd.) serving as a water-soluble polymer and 0.2 g of sodium acetate were dissolved. To the resultant, 4.0 g of the porous silica material was added and mixed to obtain 33.4 g of a slurry (7). The pH of the slurry (7) was about 7. An amount of alkali metal element relative to a solid content weight of the slurry (7) was 1.9 wt %

[0284] <Production of Humidity Conditioning Material>

[0285] A humidity conditioning material 7 was yielded in a similar manner to Example 3 except that the slurry (7) was used. The humidity conditioning material 7 contained the alkali metal element in an amount of 1.6 wt %. Table 1 shows the results.

[0286] <Evaluation of Amount of Moisture Absorbed>

[0287] An amount of moisture absorbed in the humidity conditioning material 7 was evaluated in a similar manner to Example 1. The amount of moisture absorbed in the humidity conditioning material 7 was 7 wt %. Table 1 shows the results.

Comparative Example 2

Production and Evaluation of Humidity Conditioning Material 8

[0288] <Production of Porous Silica Material>

[0289] The powdery porous silica material obtained in Example 1 was used.

[0290] <Production of Slurry>

[0291] In 29.0 g of ion-exchanged water, 0.2 g of sodium alginate 500-600 (Wako Pure Chemical Industries, Ltd.) serving as a water-soluble polymer and 0.4 g of sodium acetate were dissolved. To the resultant, 4.0 g of the porous silica material was added and mixed to obtain 33.6 g of a slurry (8). An amount of alkali metal element relative to a solid content weight of the slurry (8) was 3.3 wt %

[0292] <Production of Humidity Conditioning Material>

[0293] A humidity conditioning material 8 was yielded in a similar manner to Example 3 except that the slurry (8) was used. The humidity conditioning material 8 contained the alkali metal element in an amount of 2.5 wt %. Table 1 shows the results.

[0294] <Evaluation of Amount of Moisture Absorbed>

[0295] An amount of moisture absorbed in the humidity conditioning material 8 was evaluated in a similar manner to Example 1. The amount of moisture absorbed in the humidity conditioning material 8 was 4 wt %. Table 1 shows the results.

Comparative Example 3

Production and Evaluation of Humidity Conditioning Material 9

[0296] <Porous Silica Material>

[0297] MIZUKASIEVES Y-500 (MIZUSAWA INDUSTRIAL CHEMICALS, Ltd., sodium Y-type zeolite, SiO.sub.2/Al.sub.2O.sub.3 molar ratio=4.8, average pore diameter=0.7 to 0.8 nm, average particle diameter (D50%)=0.9 μm) was used.

[0298] <Production of Slurry>

[0299] In 29.0 g of ion-exchanged water, 0.2 g of sodium alginate 500-600 (Wako Pure Chemical Industries, Ltd.) serving as a water-soluble polymer was dissolved. To the resultant, 4.0 g of the porous silica material (MIZUKASIEVES Y-500) was added and mixed to obtain 33.2 g of a slurry (9). An amount of alkali metal element relative to a solid content weight of the slurry (9) was 10.5 wt %.

[0300] <Production of Humidity Conditioning Material>

[0301] A humidity conditioning material 9 was yielded in a similar manner to Example 1 except that the slurry (9) was used. The humidity conditioning material 9 contained the alkali metal element in an amount of 5.0 wt %. Table 1 shows the results.

[0302] <Evaluation of Amount of Moisture Absorbed>

[0303] An amount of moisture absorbed in the humidity conditioning material 9 was evaluated in a similar manner to Example 1. The amount of moisture absorbed in the humidity conditioning material 9 was 7 wt %. Table 1 shows the results.

[0304] <Evaluation of Mechanical Strength>

[0305] The humidity conditioning materials 4, 5, and 6 were each placed on a stainless steel sieve having a diameter of 160 mm, an opening of 1 mm, a wire diameter of 0.56 mm, and then, shaken with an electric sieve ANF-30 (Nitto Kagaku Co., Ltd.) for 15 minutes. A rate (%) of supported components dropped from the humidity conditioning material was calculated by the following Formula (7) or Formula (8). The smaller the rate of supported components dropped from the carrier, the higher the mechanical strength of the humidity conditioning material. Table 1 shows the results.

Rate (%) of supported components dropped from humidity conditioning material=(U−V)/(U×Z)   (7)

[0306] U: Weight (g) of humidity conditioning material, before shaking

[0307] V: Weight (g) of humidity conditioning material after shaking

[0308] Z: Total amount (parts by weight) of all components supported on 100 parts by weight of carrier in humidity conditioning material before shaking

[0309] Rate (%) of supported components dropped from humidity conditioning materials 4 to 6 among humidity conditioning materials 3 to 8 and 10 to 12 obtained by Step (4)

=(U−V)/(U×Z′)   (8)

[0310] U: Weight (g) of humidity conditioning material before shaking

[0311] V: Weight (g) of humidity conditioning material after shaking

[0312] Z′: Total amount (parts by weight) of all components supported on 100 parts by weight of carrier in humidity conditioning material before shaking

TABLE-US-00001 TABLE 1 Amount of alkali metal Average element in particle Amount Rate of humidity diameter of supported conditioning of silica moisture components material sol absorbed dropped (wt %) (nm) (wt %) ( wt % ) Example 1 0.45 20 Example 2 0.51 20 Example 3 0.44 18 Example 4 0.074 20 to 25 18 2 Example 5 0.78 12 18 Example 6 0.005 18 39 Example 7 0.026 10 to 15 26 Example 8 0.014 8 to 11 25 Example 9 0.016 4 to 6 27 Comparative 1.6 7 Example 1 Comparative 2.5 4 Example 2 Comparative 5.0 7 Example 3

INDUSTRIAL APPLICABILITY

[0313] According to an embodiment of the present invention, it is possible to obtain a humidity conditioning material capable of absorbing and desorbing a large amount of moisture.