JP5232545B2 - silica gel - Google Patents
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- JP5232545B2 JP5232545B2 JP2008162978A JP2008162978A JP5232545B2 JP 5232545 B2 JP5232545 B2 JP 5232545B2 JP 2008162978 A JP2008162978 A JP 2008162978A JP 2008162978 A JP2008162978 A JP 2008162978A JP 5232545 B2 JP5232545 B2 JP 5232545B2
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 title claims description 191
- 239000000741 silica gel Substances 0.000 title claims description 115
- 229910002027 silica gel Inorganic materials 0.000 title claims description 115
- 239000011148 porous material Substances 0.000 claims description 164
- 238000009826 distribution Methods 0.000 claims description 48
- 239000010953 base metal Substances 0.000 claims description 13
- 229910052723 transition metal Inorganic materials 0.000 claims description 13
- 150000003624 transition metals Chemical class 0.000 claims description 8
- 230000032683 aging Effects 0.000 description 51
- 238000010521 absorption reaction Methods 0.000 description 35
- 239000000377 silicon dioxide Substances 0.000 description 32
- 239000000017 hydrogel Substances 0.000 description 30
- 239000007864 aqueous solution Substances 0.000 description 23
- 238000000034 method Methods 0.000 description 16
- 230000005070 ripening Effects 0.000 description 16
- 230000000052 comparative effect Effects 0.000 description 13
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 12
- 239000002253 acid Substances 0.000 description 12
- 229910052500 inorganic mineral Inorganic materials 0.000 description 12
- 239000011707 mineral Substances 0.000 description 12
- 238000004519 manufacturing process Methods 0.000 description 11
- 229910052910 alkali metal silicate Inorganic materials 0.000 description 10
- 238000001035 drying Methods 0.000 description 9
- 238000011156 evaluation Methods 0.000 description 9
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 8
- 230000015572 biosynthetic process Effects 0.000 description 8
- 238000004364 calculation method Methods 0.000 description 8
- 238000005259 measurement Methods 0.000 description 8
- 229910052814 silicon oxide Inorganic materials 0.000 description 8
- 238000003786 synthesis reaction Methods 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 6
- 229910004298 SiO 2 Inorganic materials 0.000 description 6
- 239000004115 Sodium Silicate Substances 0.000 description 6
- 238000001879 gelation Methods 0.000 description 6
- 150000003839 salts Chemical class 0.000 description 6
- 229910052911 sodium silicate Inorganic materials 0.000 description 6
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 6
- 238000007872 degassing Methods 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- 239000000344 soap Substances 0.000 description 5
- -1 transition metal salt Chemical class 0.000 description 5
- 229910052742 iron Inorganic materials 0.000 description 4
- 229910000358 iron sulfate Inorganic materials 0.000 description 4
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 4
- 238000004438 BET method Methods 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 239000000499 gel Substances 0.000 description 3
- 229910044991 metal oxide Inorganic materials 0.000 description 3
- 150000004706 metal oxides Chemical class 0.000 description 3
- 239000011734 sodium Substances 0.000 description 3
- 238000002336 sorption--desorption measurement Methods 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 239000004111 Potassium silicate Substances 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000003841 chloride salts Chemical class 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002431 foraging effect Effects 0.000 description 1
- 239000003230 hygroscopic agent Substances 0.000 description 1
- PAZHGORSDKKUPI-UHFFFAOYSA-N lithium metasilicate Chemical compound [Li+].[Li+].[O-][Si]([O-])=O PAZHGORSDKKUPI-UHFFFAOYSA-N 0.000 description 1
- 229910052912 lithium silicate Inorganic materials 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Substances N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 229910052913 potassium silicate Inorganic materials 0.000 description 1
- NNHHDJVEYQHLHG-UHFFFAOYSA-N potassium silicate Chemical compound [K+].[K+].[O-][Si]([O-])=O NNHHDJVEYQHLHG-UHFFFAOYSA-N 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- 238000002203 pretreatment Methods 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical class [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
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Classifications
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/113—Silicon oxides; Hydrates thereof
- C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
- C01B33/14—Colloidal silica, e.g. dispersions, gels, sols
- C01B33/157—After-treatment of gels
- C01B33/158—Purification; Drying; Dehydrating
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- Chemical & Material Sciences (AREA)
- Dispersion Chemistry (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Silicon Compounds (AREA)
- Drying Of Gases (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Description
本発明は、低湿度下でも高湿度下でも優れた吸湿性能を有するシルカゲル及びその製造方法に関するものである。 The present invention relates to a silica gel having excellent moisture absorption performance under both low and high humidity and a method for producing the same.
従来のシリカゲルには、Ａ形シリカゲルとＢ形シリカゲルがあるが、ＪＩＳ Ｚ０７０１（包装用シリカゲル乾燥剤）には、Ａ形は「低湿度において湿気を吸着する力が強いもの」と、Ｂ形は「高湿度において多量の湿気を吸い、吸着容量が大きいもの」と規定され、Ａ形の相対湿度２０％、５０％及び９０％における吸湿率が、それぞれ、「８．０以上、２０．０以上、３０．０以上」と、Ｂ形の相対湿度２０％、５０％及び９０％における吸湿率が、それぞれ、「３．０以上、１０．０以上、５０．０以上」と規定されている。 Conventional silica gels include A-type silica gel and B-type silica gel, but JIS Z0701 (silica gel desiccant for packaging) has a strong A-type moisture absorption ability at low humidity. It is defined as “Absorbs a large amount of moisture at high humidity and has a large adsorption capacity”. 30.0 or higher ”and the moisture absorption rate of the B-type relative humidity at 20%, 50%, and 90% is defined as“ 3.0 or higher, 10.0 or higher, 50.0 or higher ”, respectively.
つまり、Ａ型シリカゲルは、相対湿度５０％以下の低湿度下では、比較的吸湿率が高いものの、相対湿度が高くなるに従って吸湿率が頭打ちになる。一方、Ｂ型シリカゲルは、相対湿度９０％を超えるような高湿度下では、非常に高い吸湿性を示すものの、相対湿度５０％以下では、吸湿率が非常に小さい。 That is, A-type silica gel has a relatively high moisture absorption rate at a low humidity of 50% or less, but the moisture absorption rate reaches a peak as the relative humidity increases. On the other hand, B-type silica gel exhibits a very high hygroscopic property at a high humidity exceeding 90% relative humidity, but has a very low hygroscopic rate at a relative humidity of 50% or less.
上記のように、Ａ形シリカゲルは高湿度における吸湿率が小さく、また、Ｂ形シリカゲルは低湿度における吸湿率が小さいという問題がある。このため、Ａ形シリカゲルやＢ形シリカゲルを除湿剤として使用するには、これらの除湿剤を湿度環境に応じて使い分ける必要がある。 As described above, A-type silica gel has a low moisture absorption rate at high humidity, and B-type silica gel has a low moisture absorption rate at low humidity. For this reason, in order to use A-type silica gel or B-type silica gel as a dehumidifier, it is necessary to use these dehumidifiers according to the humidity environment.
特開平９−７１４１０号公報（特許文献１）には、従来のシリカゲルに比べ吸湿率が高いシリカゲル、特に高湿度下における吸湿率が高いシリカゲルとして、細孔構造測定において細孔容積が１．０〜１．３ｃｍ３／ｇ、比表面積が７００〜８００ｍ２／ｇ、平均細孔直径が５〜７．５ｎｍであるシリカゲルが開示されている。しかし、特許文献１記載の吸湿剤は、高湿度下では高い吸湿率を示すものの、相対湿度５０％以下の低湿度下ではＡ形シリカゲルに比べ、吸湿率が低いものであった。
JP-A-9-71410 (Patent Document 1) discloses a silica gel having a higher moisture absorption rate than conventional silica gel, particularly a silica gel having a higher moisture absorption rate under high humidity. ~1.3cm 3 / g, a specific surface area of of 700-800m 2 / g, silica gel average pore diameter of 5~7.5nm is disclosed. However, although the hygroscopic agent described in
従って、本発明の目的は、低湿度下でも高湿度下でも吸湿率が高いシリカゲル及びその製造方法を提供することにある。 Accordingly, an object of the present invention is to provide a silica gel having a high moisture absorption rate under a low humidity and a high humidity and a method for producing the same.
かかる実情において、本発明者らは鋭意検討を行った結果、（１）ｐＨ１０．５〜１１．５で珪酸アルカリからシリカゾルを形成させ、ゲル化し、次いで、得られたシリカヒドロゲルを、ｐＨ４〜７とｐＨ０．５〜２の２段階で熟成を行うことにより、従来のＡ形シリカゲルには殆どなかった、５〜２５ｎｍの細孔直径の細孔を形成させることができること、（２）そのような細孔を有するシリカゲルは、細孔容積が０．４５〜１．０ｃｍ３／ｇとＡ形シリカゲルより多いにもかかわらず、細孔直径２．５ｎｍ以下の領域に細孔分布のピーク（最大値）を有していること、（３）更には、細孔直径５〜２５ｎｍの合計細孔容積（Ｖ１）と細孔直径２〜２５ｎｍの合計細孔容積（Ｖ２）の比（Ｖ１）／（Ｖ２）が、０．２５〜０．７であり、Ａ形シリカゲルに比べ、細孔直径５〜２５ｎｍの細孔の合計細孔容積が非常に大きいこと。（４）そして、これらの物性を有するシリカゲルは、ＲＨ２０％〜５０％の低湿度下でもＲＨ９０％の高湿度下でも、高い吸湿率を示すこと等を見出し、本発明を完成するに至った。 Under such circumstances, as a result of intensive studies, the present inventors have (1) formed a silica sol from an alkali silicate at pH 10.5 to 11.5, gelled, and then obtained silica hydrogel was adjusted to pH 4 to 7 And aging in two stages of pH 0.5 to 2, it is possible to form pores having a pore diameter of 5 to 25 nm, which was hardly found in conventional A-type silica gel, (2) Although the silica gel having pores has a pore volume of 0.45 to 1.0 cm 3 / g, which is larger than that of A-type silica gel, the peak of the pore distribution (maximum value) in the region having a pore diameter of 2.5 nm or less. (3) Furthermore, the ratio (V 1 ) of the total pore volume (V 1 ) having a pore diameter of 5 to 25 nm and the total pore volume (V 2 ) having a pore diameter of 2 to 25 nm ) / (V 2 ) is 0.25 to 0.7 That is, the total pore volume of pores having a pore diameter of 5 to 25 nm is much larger than that of A-type silica gel. (4) The silica gel having these physical properties has been found to exhibit a high moisture absorption rate under a low humidity of RH 20% to 50% and a high humidity of RH 90%, and the present invention has been completed.
全細孔容積が０．４５〜１．０ｃｍ３／ｇであり、且つ、細孔直径２．５ｎｍ以下の領域に細孔分布のピーク（最大値）が存在し、細孔直径５〜２５ｎｍの合計細孔容積（Ｖ １ ）と細孔直径２〜２５ｎｍの合計細孔容積（Ｖ ２ ）の比（Ｖ １ ）／（Ｖ ２ ）が、０．２５〜０．７であることを特徴とするシリカゲルを提供するものである。 The total pore volume is 0.45 to 1.0 cm 3 / g, and a peak (maximum value) of pore distribution exists in a region having a pore diameter of 2.5 nm or less, and the pore diameter is 5 to 25 nm. The ratio (V 1 ) / (V 2 ) of the total pore volume (V 1 ) to the total pore volume (V 2 ) of the pore diameter of 2 to 25 nm is 0.25 to 0.7, A silica gel is provided.
本発明によれば、低湿度下でも高湿度下でも吸湿率が高いシリカゲル及びその製造方法を提供することができる。 According to the present invention, it is possible to provide a silica gel having a high moisture absorption rate at a low humidity or a high humidity and a method for producing the same.
本発明のシリカゲルは、全細孔容積が０．４５〜１．０ｃｍ３／ｇであり、且つ、細孔直径２．５ｎｍ以下の領域に細孔分布のピーク（最大値）が存在するシリカゲルである。 The silica gel of the present invention is a silica gel having a total pore volume of 0.45 to 1.0 cm 3 / g and having a pore distribution peak (maximum value) in a region having a pore diameter of 2.5 nm or less. is there.
本発明のシリカゲルの全細孔容積は、０．４５〜１．０ｃｍ３／ｇ、好ましくは０．５５〜０．７５ｃｍ３／ｇである。全細孔容積が上記範囲にあり、且つ、細孔直径２．５ｎｍ以下の領域に細孔分布のピーク（最大値）が存在し、細孔直径５〜２５ｎｍの細孔を有することで、Ａ形シリカゲルでありながら、高湿度下での吸湿率が高くなる。一方、全細孔容積が、上記範囲未満だと、高湿度下での吸湿率が低くなり、また、上記範囲を超えると、低湿度下での吸湿率が低くなる。なお、本発明において、全細孔容積は、日本ベル社製ベルソープＭｉｎｉを使用し、１５０℃で３時間真空加熱脱気による前処理後、測定を行い、ＢＥＴ法により計算して求めた値である。 The total pore volume of the silica gel of the present invention is 0.45 to 1.0 cm 3 / g, preferably 0.55 to 0.75 cm 3 / g. The peak of the pore distribution (maximum value) exists in the region where the total pore volume is in the above range and the pore diameter is 2.5 nm or less, and the pore has a pore diameter of 5 to 25 nm. Although it is a silica gel, the moisture absorption rate under high humidity is increased. On the other hand, if the total pore volume is less than the above range, the moisture absorption rate under high humidity is low, and if it exceeds the above range, the moisture absorption rate under low humidity is low. In the present invention, the total pore volume is a value obtained by performing measurement after pretreatment by vacuum heating and degassing at 150 ° C. for 3 hours using a bell soap Mini manufactured by Nippon Bell Co., Ltd., and calculating by the BET method. is there.
本発明のシリカゲルは、細孔直径２．５ｎｍ以下の領域に細孔分布のピーク（最大値）が存在する。細孔直径２．５ｎｍ以下の領域に細孔分布のピーク（最大値）が存在することにより、低湿度下での吸湿率が高くなる。一方、細孔直径２．５ｎｍを超える領域に細孔分布のピーク（最大値）が存在すると、低湿度下での吸湿率が低くなる。 The silica gel of the present invention has a pore distribution peak (maximum value) in a region having a pore diameter of 2.5 nm or less. The presence of a pore distribution peak (maximum value) in a region having a pore diameter of 2.5 nm or less increases the moisture absorption rate under low humidity. On the other hand, if there is a peak (maximum value) of pore distribution in a region exceeding the pore diameter of 2.5 nm, the moisture absorption rate under low humidity becomes low.
そして、本発明のシリカゲルの、細孔直径５〜２５ｎｍの合計細孔容積（Ｖ１）と細孔直径２〜２５ｎｍの合計細孔容積（Ｖ２）の比（Ｖ１）／（Ｖ２）が、０．２５〜０．７であることが好ましく、０．２５〜０．５５であることが特に好ましい。（Ｖ１）／（Ｖ２）の値が、上記範囲にあることにより、低湿度下でも高湿度下でも吸湿率が高くなるという本発明の効果が高まる。一方、（Ｖ１）／（Ｖ２）の値が、上記範囲より小さいと、高湿度下での吸湿率が低くなり、また、上記範囲より大きいと、低湿度下での吸湿率が低くなる。 Then, the silica gel of the present invention, the ratio of the total pore volume of pores having a pore diameter of 5 to 25 nm (V 1) and the total pore volume of pores having a pore diameter 2~25nm (V 2) (V 1 ) / (V 2) Is preferably 0.25 to 0.7, and particularly preferably 0.25 to 0.55. When the value of (V 1 ) / (V 2 ) is in the above range, the effect of the present invention that the moisture absorption rate is high at low humidity or high humidity is enhanced. On the other hand, if the value of (V 1 ) / (V 2 ) is smaller than the above range, the moisture absorption rate under high humidity is low, and if it is larger than the above range, the moisture absorption rate under low humidity is low. .
本発明において、細孔分布のピーク（最大値）及び（Ｖ１）／（Ｖ２）は、日本ベル社製ベルソープＭｉｎｉを使用し、１５０℃で３時間真空加熱脱気による前処理後、測定を行い、公知のＢＪＨ法による細孔分布計算結果から求められる。これらについて、図１を参照して説明する。図１中、符号１で示す曲線は、本発明の一例のシリカゲルのＢＪＨ法による細孔分布計算結果得られた細孔分布曲線である。図１中、細孔分布曲線１は、２ｎｍ付近にピーク（最高値）（符号２）を有している。そして、そのピーク（最大値）２の位置は、２．５ｎｍ以下の領域にある。よって、図１に示す細孔分布曲線を有するシリカゲルでは、細孔直径２．５ｎｍ以下の領域に細孔分布のピーク（最大値）が存在する。また、図２中、符号３に示す細孔分布曲線のように、細孔分布曲線が１ｎｍ付近まで上昇し続けている場合、ピーク（最大値）が観察されないが、該細孔分布曲線３からは、２．５ｎｍ以下の範囲にピーク（最大値）があることは明らかなので、このよう場合も、細孔直径２．５ｎｍ以下に細孔分布のピーク（最大値）が存在すると言える。なお、ＢＪＨ法による細孔分布計算では、精度よく測定できる下限は、細孔直径が２ｎｍであるが、細孔直径が１〜２ｎｍであっても、精度は下がるものの細孔の存在及び細孔容積を測定することはできる。
In the present invention, the peak (maximum value) and (V 1 ) / (V 2 ) of the pore distribution are measured after pretreatment by vacuum heat degassing at 150 ° C. for 3 hours using Bell Soap Mini by Nippon Bell Co., Ltd. Is obtained from the pore distribution calculation result by a known BJH method. These will be described with reference to FIG. In FIG. 1, a curve indicated by
また、細孔直径５〜２５ｎｍの合計細孔容積（Ｖ１）は、図１中、５〜２５ｎｍの範囲の細孔分布曲線とＸ軸に囲まれた部分（図１中、左上から右下に向かう斜線で示す部分）の面積であり、５〜２５ｎｍの細孔容積の積算値である。また、細孔直径２〜２５ｎｍの合計細孔容積（Ｖ２）は、図１中、２〜２５ｎｍの範囲の細孔分布曲線とＸ軸に囲まれた部分（図１中、右上から左下に向かう斜線で示す部分）の面積であり、２〜２５ｎｍの細孔容積の積算値である。 Further, the total pore volume (V 1 ) having a pore diameter of 5 to 25 nm is the portion surrounded by the pore distribution curve and the X axis in the range of 5 to 25 nm in FIG. 1 (in FIG. 1, from upper left to lower right). The area indicated by the oblique lines toward the surface) is the integrated value of the pore volume of 5 to 25 nm. In addition, the total pore volume (V 2 ) having a pore diameter of 2 to 25 nm is the portion surrounded by the pore distribution curve and the X axis in the range of 2 to 25 nm in FIG. 1 (from the upper right to the lower left in FIG. 1). This is the integrated area of the pore volume of 2 to 25 nm.
該ＢＪＨ法による細孔分布計算において、細孔の測定は、窒素吸着等温線測定方法であり、解析は細孔形状が円筒形であるという仮定に基づいている。なお、細孔直径１〜２ｎｍの測定精度は、細孔直径２ｎｍ以上の測定精度に比べ下がるため、また、細孔直径２５ｎｍを超える細孔は無視できるほど少ないため、合計細孔容積の比の計算では、２〜２５ｎｍの範囲において行った。また、（Ｖ１）及び（Ｖ２）は細孔分布曲線から手計算又は自動計算により求めることができる。 In the pore distribution calculation by the BJH method, the pore measurement is a nitrogen adsorption isotherm measurement method, and the analysis is based on the assumption that the pore shape is cylindrical. The measurement accuracy of the pore diameter of 1-2 nm is lower than the measurement accuracy of the pore diameter of 2 nm or more, and the number of pores exceeding the pore diameter of 25 nm is negligibly small. The calculation was performed in the range of 2 to 25 nm. Further, (V 1 ) and (V 2 ) can be obtained from the pore distribution curve by manual calculation or automatic calculation.
本発明のシリカゲルには、図１に示す細孔分布のように、細孔分布のピーク（最大値）が２．５ｎｍ以下の領域に存在し、且つ、細孔直径が５ｎｍ以上の大きな細孔も多く存在している。一方、従来のＡ形シリカゲルは、細孔分布のピーク（最大値）が２．５ｎｍ以下の領域に存在するものの、細孔直径が５ｎｍ以上の大きな細孔はほとんどない。また、従来のＢ形シリカゲルは、例えば細孔直径４．０〜８．０ｎｍの領域において細孔分布のピーク（最大値）が存在する。 In the silica gel of the present invention, the pore distribution peak (maximum value) exists in a region of 2.5 nm or less and the pore diameter is 5 nm or more as shown in FIG. There are many. On the other hand, the conventional A-type silica gel has a pore distribution peak (maximum value) in a region of 2.5 nm or less, but has few large pores having a pore diameter of 5 nm or more. Further, the conventional B-type silica gel has a peak (maximum value) of pore distribution in a region having a pore diameter of 4.0 to 8.0 nm, for example.
本発明のシリカゲルの比表面積は５８０〜９００ｍ２／ｇ、平均細孔直径は２．５〜５ｎｍの範囲である。なお、本発明において、比表面積及び平均細孔直径は、日本ベル社製ベルソープＭｉｎｉを使用し、１５０℃で３時間真空加熱脱気による前処理後、測定を行い、ＢＥＴ法により計算して求めたものである。 The specific surface area of the silica gel of the present invention is 580 to 900 m 2 / g, and the average pore diameter is in the range of 2.5 to 5 nm. In the present invention, the specific surface area and the average pore diameter are obtained by pre-treatment by vacuum heat degassing at 150 ° C. for 3 hours using Bell Soap Mini manufactured by Bell Japan, and calculating by BET method. It is a thing.
本発明のシリカゲルは、遷移金属又は卑金属を含有するものであってもよい。本発明のシリカゲルが、遷移金属又は卑金属を含有することにより、吸脱着性能が高くなる。すなわち、本発明の好適なシリカゲルは、シリカゲルとしての酸化珪素に対して、遷移金属又は卑金属の酸化物が配合されている。該遷移金属又は該卑金属の酸化物の配合量としては、酸化珪素１００質量部中、０．１〜１０．０質量部である。該遷移金属及び該卑金属としては、鉄、チタン、アルミニウム、ジルコニウムが挙げられ、これらのうち、鉄が吸脱着性能に優れる点で好ましい。 The silica gel of the present invention may contain a transition metal or a base metal. The silica gel of the present invention contains a transition metal or a base metal, so that the adsorption / desorption performance is enhanced. That is, the preferred silica gel of the present invention contains a transition metal or base metal oxide to silicon oxide as silica gel. As a compounding quantity of this transition metal or this base metal oxide, it is 0.1-10.0 mass parts in 100 mass parts of silicon oxides. Examples of the transition metal and the base metal include iron, titanium, aluminum, and zirconium. Of these, iron is preferable in that it has excellent adsorption / desorption performance.
本発明のシリカゲルの製造方法は、珪酸アルカリ水溶液に鉱酸水溶液を加えて、ｐＨ１０．５〜１１．５でゾルを形成後、ゲル化させて、熟成前シリカヒドロゲルを得るゲル化工程と、
該熟成前シリカヒドロゲルを、ｐＨ４〜７で一次熟成し、一次熟成シリカヒドロゲルを得る一次熟成工程と、
該一次熟成シリカヒドロゲルを、ｐＨ０．５〜２で二次熟成し、二次熟成シリカヒドロゲルを得る二次熟成工程と、
該二次熟成シリカヒドロゲルを乾燥し、シリカゲルを得る乾燥工程と、
を有するシリカゲルの製造方法である。
The method for producing silica gel of the present invention includes a gelation step of adding a mineral acid aqueous solution to an alkali silicate aqueous solution, forming a sol at pH 10.5 to 11.5, and then gelling to obtain a silica hydrogel before aging,
A primary aging step in which the pre-aged silica hydrogel is primary-aged at a pH of 4 to 7 to obtain a primary-aged silica hydrogel;
A secondary aging step of secondary aging the primary aging silica hydrogel at a pH of 0.5 to 2 to obtain a secondary aging silica hydrogel;
Drying the secondary aged silica hydrogel to obtain silica gel;
It is a manufacturing method of the silica gel which has this.
本発明のシリカゲルの製造方法に係る該ゲル化工程は、該珪酸アルカリ水溶液から該熟成前シリカヒドロゲルを得る工程である。 The gelation step according to the method for producing silica gel of the present invention is a step of obtaining the pre-ripening silica hydrogel from the alkali silicate aqueous solution.
該珪酸アルカリ水溶液は、珪酸ナトリウム、珪酸カリウム、珪酸リチウム等の珪酸アルカリの水溶液である。例えば、該珪酸アルカリ水溶液が珪酸ナトリウムの場合、のＳｉＯ２／Ｎａ２Ｏ（モル比）は、２〜３．３が好ましく、このような珪酸アルカリ水溶液としては、ＪＩＳ ３号珪酸ナトリウム水溶液、１号珪酸ナトリウム水溶液が挙げられる。該珪酸アルカリ水溶液中のＳｉＯ２濃度は、５〜１５質量％が好ましい。 The alkali silicate aqueous solution is an aqueous solution of an alkali silicate such as sodium silicate, potassium silicate, or lithium silicate. For example, when the alkali silicate aqueous solution is sodium silicate, the SiO 2 / Na 2 O (molar ratio) is preferably 2 to 3.3. As such an alkali silicate aqueous solution, JIS No. 3 sodium silicate aqueous solution, 1 No. sodium silicate aqueous solution. The SiO 2 concentration in the alkali silicate aqueous solution is preferably 5 to 15% by mass.
該鉱酸水溶液に係る鉱酸としては、例えば、硫酸、塩酸が挙げられる。なお、後述する、該一次熟成工程及び該二次熟成工程に係る鉱酸も同様である。 Examples of the mineral acid related to the mineral acid aqueous solution include sulfuric acid and hydrochloric acid. In addition, the mineral acid which concerns on this primary aging process and this secondary aging process mentioned later is also the same.
そして、該ゲル化工程では、先ず、ｐＨ１０．５〜１１．５の範囲で、該珪酸アルカリ水溶液に該鉱酸水溶液を加え、ｐＨ１０．５〜１１．５のゾルを形成させる。該ゲル化工程で、該珪酸アルカリ水溶液に該鉱酸水溶液を加える際のｐＨが、１０．５未満だと、該鉱酸水溶液添加時にゲル化してしまうため、不均一なゲルとなり、一方、ｐＨが１１．５を超えると、ｐＨが珪酸アルカリのｐＨと同程度になるためシリカのゾルが殆ど形成されず、ゲル化に時間がかかり過ぎる。該珪酸アルカリ水溶液に該鉱酸水溶液を加える際の温度は、１５〜３５℃である。次いで、得られた該ｐＨ１０．５〜１１．５のゾルを、１５〜３５℃で放置して、好ましくは１５〜３５℃で２０〜３０分間放置してゲル化させて、該熟成前シリカヒドロゲルを得る。その後、得られた該熟成前シリカヒドロゲルを、５〜１０ｍｍ程度の大きさに粉砕する。 In the gelation step, first, the aqueous mineral acid solution is added to the alkaline silicate aqueous solution in the range of pH 10.5 to 11.5 to form a sol having a pH of 10.5 to 11.5. In the gelation step, if the pH of the mineral acid aqueous solution is less than 10.5 when the mineral acid aqueous solution is added, gelation occurs when the mineral acid aqueous solution is added, resulting in a non-uniform gel. When the value exceeds 11.5, the pH becomes approximately the same as the pH of the alkali silicate, so that almost no silica sol is formed, and it takes too much time for gelation. The temperature for adding the mineral acid aqueous solution to the alkali silicate aqueous solution is 15 to 35 ° C. Next, the obtained sol having a pH of 10.5 to 11.5 is allowed to stand at 15 to 35 ° C., preferably at 15 to 35 ° C. for 20 to 30 minutes to be gelled. Get. Thereafter, the obtained pre-aging silica hydrogel is pulverized to a size of about 5 to 10 mm.
該一次熟成工程は、該熟成前シリカヒドロゲルを、ｐＨ４〜７で一次熟成して、該一次熟成シリカヒドロゲルを得る工程である。 The primary aging step is a step of primary aging the silica hydrogel before aging at pH 4 to 7 to obtain the primary aging silica hydrogel.
該一次熟成工程では、水に、該熟成前シリカヒドロゲルを加え、鉱酸で、ｐＨを、４〜７に調節し、加熱して、一次熟成を行う。該一次熟成の際のｐＨが４未満だと、細孔直径が５ｎｍ以上の大きい細孔が少なくなるため、全細孔容積が少なり、そのため、高湿度下での吸湿率が低くなる。また、該一次熟成の際のｐＨが７を超えると、細孔直径が５ｎｍ以上の大きい細孔が多くなり過ぎるため、細孔直径が２〜５ｎｍの小さい細孔が少なくなるので、低湿度下での吸湿率が低くなる。また、該一次熟成工程を行わずに、０．５〜２程度の低いｐＨ領域でのみ熟成を行うと、細孔直径が５ｎｍ以上の大きい細孔がほとんど形成されないので、高湿度下での吸湿率が低くなる。該一次熟成工程で一次熟成する際、熟成温度は、３０〜４０℃であり、また、熟成時間は０．３〜１時間である。その後、得られた該一次熟成シリカヒドロゲルをろ過する。 In the primary aging step, the silica hydrogel before aging is added to water, the pH is adjusted to 4 to 7 with a mineral acid, and the primary aging is performed by heating. When the pH during the primary ripening is less than 4, large pores having a pore diameter of 5 nm or more are reduced, so that the total pore volume is reduced. Therefore, the moisture absorption rate under high humidity is lowered. Further, if the pH during the primary ripening exceeds 7, the number of large pores having a pore diameter of 5 nm or more is excessively increased, so that the number of small pores having a pore diameter of 2 to 5 nm is reduced. Hygroscopicity at low. Further, when the aging is performed only in a low pH range of about 0.5 to 2 without performing the primary aging step, large pores having a pore diameter of 5 nm or more are hardly formed, so that moisture absorption under high humidity is performed. The rate is lowered. In primary ripening in the primary ripening step, the aging temperature is 30 to 40 ° C., and the aging time is 0.3 to 1 hour. Thereafter, the obtained primary aged silica hydrogel is filtered.
該二次熟成工程は、該一次熟成シリカヒドロゲルを、ｐＨ０．５〜２で二次熟成して、該二次熟成シリカヒドロゲルを得る工程である。 The secondary aging step is a step of obtaining the secondary aging silica hydrogel by secondary aging the primary aging silica hydrogel at pH 0.5-2.
該二次熟成工程では、水に、該一次熟成シリカヒドロゲルを加え、鉱酸を加えてｐＨを、０．５〜２に調節し、加熱して、二次熟成を行う。該二次熟成の際のｐＨが０．５未満だと、細孔直径が５ｎｍ以上の大きい細孔が少なくなるため、全細孔容積が少なくなり、そのため、高湿度下での吸湿率が低くなる。また、該二次熟成の際のｐＨが２を超えると、細孔直径２〜５ｎｍの小さい細孔が形成され難くなり、細孔直径が小さい細孔が少なくなるので、低湿度下での吸湿率が低くなる。該二次熟成工程で二次熟成する際、熟成温度は、３０〜４０℃であり、また、熟成時間は１〜２時間である。その後、得られた該二次熟成シリカヒドロゲルを、水洗し、ろ過する。 In the secondary aging step, the primary aging silica hydrogel is added to water, a mineral acid is added to adjust the pH to 0.5 to 2, and the secondary aging is performed by heating. If the pH during the secondary ripening is less than 0.5, the number of large pores having a pore diameter of 5 nm or more is reduced, so that the total pore volume is reduced. Therefore, the moisture absorption rate under high humidity is low. Become. Further, when the pH during the secondary aging exceeds 2, it becomes difficult to form small pores having a pore diameter of 2 to 5 nm, and pores having a small pore diameter are reduced. The rate is lowered. When secondary ripening is performed in the secondary ripening step, the aging temperature is 30 to 40 ° C., and the aging time is 1 to 2 hours. Thereafter, the obtained secondary aging silica hydrogel is washed with water and filtered.
該乾燥工程は、該二次熟成シリカヒドロゲルを乾燥して、シリカゲルを得る工程である。 The drying step is a step of drying the secondary aging silica hydrogel to obtain silica gel.
該乾燥工程で、乾燥を行う際の乾燥温度は、１００〜１５０℃、また、乾燥時間は３〜１５時間である。 In the drying step, the drying temperature at the time of drying is 100 to 150 ° C., and the drying time is 3 to 15 hours.
本発明のシリカゲルの製造方法に係る該二次熟成工程では、水に、鉱酸を加えて、ｐＨを調節するが、その際に、水に、該遷移金属塩又は卑金属塩も加えることにより、該二次熟成工程を、遷移金属塩又は卑金属塩の存在下で行うことができる。このことにより、シリカゲルとしての酸化珪素に対して、遷移金属又は卑金属の酸化物を配合（ドープ）させることができる。 In the secondary ripening step according to the method for producing silica gel of the present invention, mineral acid is added to water to adjust the pH, and at that time, by adding the transition metal salt or base metal salt to water, The secondary aging step can be performed in the presence of a transition metal salt or a base metal salt. Thus, transition metal or base metal oxide can be blended (doped) with silicon oxide as silica gel.
該遷移金属塩又は該卑金属塩に係る遷移金属又は卑金属としては、鉄、チタン、アルミニウム、ジルコニウムが挙げられ、これらのうち、鉄が吸脱着性能に優れる点で好ましい。また、該遷移金属塩又は該卑金属塩に係る塩としては、特に制限されず、塩化物塩、硫酸塩、硝酸塩、酢酸塩が挙げられる。該遷移金属塩又は該卑金属塩の添加量は、酸化物換算で、酸化珪素１００質量部に対して、０．１〜１０．０質量部である。 Examples of the transition metal or base metal related to the transition metal salt or the base metal salt include iron, titanium, aluminum, and zirconium. Of these, iron is preferable in that it has excellent adsorption / desorption performance. Moreover, it does not restrict | limit especially as salt concerning this transition metal salt or this base metal salt, A chloride salt, sulfate, nitrate, acetate is mentioned. The addition amount of the transition metal salt or the base metal salt is 0.1 to 10.0 parts by mass with respect to 100 parts by mass of silicon oxide in terms of oxide.
本発明のシリカゲルの製造方法は、本発明のシリカゲルを製造するために、好適に用いられる。 The method for producing the silica gel of the present invention is suitably used for producing the silica gel of the present invention.
本発明のシリカゲル及び本発明のシリカゲルの製造方法により得られるシリカゲルは、ＪＩＳ Ｚ０７０１に基づく、２５℃の吸湿率が、相対湿度２０％において１０〜１３．２重量％、相対湿度５０％において２４．０〜２９．０重量％、相対湿度９０％において４５．０〜６７．５重量％である。つまり、本発明のシリカゲル及び本発明のシリカゲルの製造方法により得られるシリカゲルは、低湿度下での吸湿率が、従来のＡ形シリカゲルと同等又はそれ以上であり、且つ、高湿度下での吸湿率が、従来のＢ形シリカゲルと同程度又はそれ以上である。よって、本発明のシリカゲル及び本発明のシリカゲルの製造方法により得られるシリカゲルは、低湿度下でも高湿度下でも優れた吸湿性能を示す。そのため、本発明のシリカゲル及び本発明のシリカゲルの製造方法により得られるシリカゲルは、回転再生式除湿機用の除湿剤として、優れた性能を発揮する。 The silica gel of the present invention and the silica gel obtained by the method for producing the silica gel of the present invention have a moisture absorption rate of 10 to 13.2% by weight at 25% relative humidity and 24.3% at 50% relative humidity based on JIS Z0701. 0 to 29.0% by weight and 45.0 to 67.5% by weight at 90% relative humidity. That is, the silica gel of the present invention and the silica gel obtained by the method of producing the silica gel of the present invention have a moisture absorption rate at low humidity that is equal to or higher than that of conventional A-type silica gel, and moisture absorption at high humidity. The rate is about the same as or higher than that of conventional B-type silica gel. Therefore, the silica gel obtained by the silica gel of the present invention and the method for producing the silica gel of the present invention exhibits excellent moisture absorption performance at both low and high humidity. Therefore, the silica gel obtained by the silica gel of the present invention and the method for producing the silica gel of the present invention exhibits excellent performance as a dehumidifying agent for a rotary regenerative dehumidifier.
次に、実施例を挙げて本発明を更に具体的に説明するが、これは単に例示であって、本発明を制限するものではない。 EXAMPLES Next, although an Example is given and this invention is demonstrated more concretely, this is only an illustration and does not restrict | limit this invention.
（シリカゲルの合成）
＜ゲル化工程＞
ＳｉＯ２／Ｎａ２Ｏ（モル比）＝３の珪酸ナトリウム（ＪＩＳ ３号）水溶液（ＳｉＯ２濃度１０％）に、１２％濃度の硫酸水溶液を、２０℃で添加して、ｐＨ１１のゾルを形成させた。次いで、該ゾルを、２０℃で２０分間放置し、ゲル化させ、熟成前シリカヒドロゲルを得た。次いで、得られた熟成前シリカヒドロゲルを、５〜１０ｍｍ程度に粉砕した。
＜一次熟成工程＞
次いで、得られた熟成前シリカヒドロゲルを水に加え、２％濃度の硫酸水溶液を添加して、ｐＨを５．５に調節し、３５℃で３０分間加熱し、熟成を行った。熟成後、ろ過して、一次熟成シリカヒドロゲルを得た。
＜二次熟成工程＞
次いで、得られた一次熟成シリカヒドロゲルを水に加え、硫酸と、硫酸鉄（酸化鉄換算で、酸化珪素１００質量部に対して３質量部）とを水溶液にして添加して、ｐＨを１．４に調節し、３５℃で９０分間加熱し、熟成した。熟成後、ろ過して、二次熟成シリカヒドロゲルを得た。
＜乾燥工程＞
次いで、得られた二次熟成シリカヒドロゲルを、１１０℃で１５時間乾燥し、シリカゲルを得た。
(Synthesis of silica gel)
<Gelification process>
A 12% sulfuric acid aqueous solution is added at 20 ° C. to a sodium silicate (JIS 3) aqueous solution (SiO 2 concentration 10%) having a SiO 2 / Na 2 O (molar ratio) = 3 to form a sol having a pH of 11 I let you. Next, the sol was allowed to stand at 20 ° C. for 20 minutes to be gelled to obtain a silica hydrogel before aging. Next, the obtained pre-ripening silica hydrogel was pulverized to about 5 to 10 mm.
<Primary aging process>
Next, the obtained silica hydrogel before aging was added to water, a 2% strength aqueous sulfuric acid solution was added to adjust the pH to 5.5, and the mixture was heated at 35 ° C. for 30 minutes for aging. After aging, filtration was performed to obtain a primary aging silica hydrogel.
<Secondary aging process>
Subsequently, the obtained primary aging silica hydrogel was added to water, and sulfuric acid and iron sulfate (3 parts by mass with respect to 100 parts by mass of silicon oxide in terms of iron oxide) were added as an aqueous solution to adjust the pH to 1. 4 and heated at 35 ° C. for 90 minutes to age. After aging, filtration was performed to obtain a secondary aging silica hydrogel.
<Drying process>
Subsequently, the obtained secondary aging silica hydrogel was dried at 110 ° C. for 15 hours to obtain silica gel.
（シリカゲルの評価）
＜物性測定＞
日本ベル社製ベルソープＭｉｎｉを使用し、１５０℃で３時間真空加熱脱気による前処理後、得られたシリカゲルの測定を行い、ＢＥＴ法による比表面積、全細孔容積、平均細孔径を計算した。その結果を、表１に示す。
＜細孔分布＞
日本ベル社製ベルソープＭｉｎｉを使用し、１５０℃で３時間真空加熱脱気による前処理後、得られたシリカゲルの測定を行い、ＢＪＨ法による細孔分布計算により、細孔分布曲線を求めた。その結果を図３に示す。また、得られた細孔分布曲線から、細孔直径５〜２５ｎｍの合計細孔容積（Ｖ１）、細孔直径２〜２５ｎｍの合計細孔容積（Ｖ２）を求めた。その結果を表１に示す。
＜吸湿試験＞
得られたシリカゲルの吸湿試験を、ＪＩＳ Ｚ０７０１に準拠して行った。その結果を表３に示す。
(Evaluation of silica gel)
<Measurement of physical properties>
Using a Bell Soap Mini manufactured by Nippon Bell Co., Ltd., after pretreatment by vacuum heating and degassing at 150 ° C. for 3 hours, the obtained silica gel was measured, and the specific surface area, total pore volume, and average pore diameter were calculated by the BET method. . The results are shown in Table 1.
<Pore distribution>
Using a bell soap Mini manufactured by Nippon Bell Co., Ltd., pretreatment by vacuum heating and degassing at 150 ° C. for 3 hours, the obtained silica gel was measured, and a pore distribution curve was obtained by pore distribution calculation by the BJH method. The result is shown in FIG. Further, from the obtained pore distribution curve, the total pore volume (V 1 ) having a pore diameter of 5 to 25 nm and the total pore volume (V 2 ) having a pore diameter of 2 to 25 nm were determined. The results are shown in Table 1.
<Hygroscopic test>
The obtained silica gel was subjected to a moisture absorption test in accordance with JIS Z0701. The results are shown in Table 3.
（実施例２）
（シリカゲルの合成）
一次熟成工程で、ｐＨを５．５に調節することに代えて、ｐＨを４．８に調節すること以外は、実施例１と同様の方法で行い、シリカゲルを得た。
（シリカゲルの評価）
実施例１と同様の方法で行った。その結果を、表１、表３及び図４に示す。
(Example 2)
(Synthesis of silica gel)
In the primary ripening step, silica gel was obtained in the same manner as in Example 1 except that the pH was adjusted to 4.8 instead of adjusting the pH to 5.5.
(Evaluation of silica gel)
The same method as in Example 1 was used. The results are shown in Table 1, Table 3, and FIG.
（実施例３）
（シリカゲルの合成）
一次熟成工程で、ｐＨを５．５に調節することに代えて、ｐＨを６．５に調節すること以外は、実施例１と同様の方法で行い、シリカゲルを得た。
（シリカゲルの評価）
実施例１と同様の方法で行った。その結果を、表１、表３及び図５に示す。
(Example 3)
(Synthesis of silica gel)
In the primary ripening step, silica gel was obtained in the same manner as in Example 1 except that the pH was adjusted to 6.5 instead of adjusting the pH to 5.5.
(Evaluation of silica gel)
The same method as in Example 1 was used. The results are shown in Table 1, Table 3, and FIG.
（実施例４）
（シリカゲルの合成）
一次熟成工程で、ｐＨを５．５に調節することに代えて、ｐＨを４．９に調節すること、及び二次熟成工程で、硫酸鉄（酸化鉄換算で、酸化珪素１００質量部に対して３質量部）に代えて、硫酸アルミニウム（酸化アルミニウム換算で、酸化珪素１００質量部に対して２．２質量部）とする以外は、実施例１と同様の方法で行い、シリカゲルを得た。
（シリカゲルの評価）
実施例１と同様の方法で行った。その結果を、表１、表３及び図６に示す。
Example 4
(Synthesis of silica gel)
Instead of adjusting the pH to 5.5 in the primary aging step, adjusting the pH to 4.9, and in the secondary aging step, iron sulfate (based on 100 parts by mass of silicon oxide in terms of iron oxide) The silica gel was obtained in the same manner as in Example 1 except that aluminum sulfate (2.2 parts by mass with respect to 100 parts by mass of silicon oxide in terms of aluminum oxide) was used instead of 3 parts by mass). .
(Evaluation of silica gel)
The same method as in Example 1 was used. The results are shown in Table 1, Table 3, and FIG.
（実施例５）
（シリカゲルの合成）
一次熟成工程で、ｐＨを５．５に調節することに代えて、ｐＨを４．９に調節すること、及び二次熟成工程で、硫酸鉄を添加しないこと以外は、実施例１と同様の方法で行い、シリカゲルを得た。
（シリカゲルの評価）
実施例１と同様の方法で行った。その結果を、表１、表３及び図７に示す。
(Example 5)
(Synthesis of silica gel)
Instead of adjusting the pH to 5.5 in the primary aging step, the same as in Example 1 except that the pH is adjusted to 4.9 and no iron sulfate is added in the secondary aging step. In this way, silica gel was obtained.
(Evaluation of silica gel)
The same method as in Example 1 was used. The results are shown in Table 1, Table 3, and FIG.
（比較例１）
（シリカゲルの合成）
一次熟成工程で、ｐＨを５．５に調節することに代えて、ｐＨを３．１に調節すること以外は、実施例１と同様の方法で行い、シリカゲルを得た。
（シリカゲルの評価）
実施例１と同様の方法で行った。その結果を、表２、表４及び図８に示す。
(Comparative Example 1)
(Synthesis of silica gel)
In the primary ripening step, silica gel was obtained in the same manner as in Example 1 except that the pH was adjusted to 3.1 instead of adjusting the pH to 5.5.
(Evaluation of silica gel)
The same method as in Example 1 was used. The results are shown in Table 2, Table 4, and FIG.
（比較例２）
（シリカゲルの合成）
一次熟成工程で、ｐＨを５．５に調節することに代えて、ｐＨを９．７に調節すること以外は、実施例１と同様の方法で行い、シリカゲルを得た。
（シリカゲルの評価）
実施例１と同様の方法で行った。その結果を、表２、表４及び図８に示す。
(Comparative Example 2)
(Synthesis of silica gel)
In the primary ripening step, silica gel was obtained in the same manner as in Example 1 except that the pH was adjusted to 9.7 instead of adjusting the pH to 5.5.
(Evaluation of silica gel)
The same method as in Example 1 was used. The results are shown in Table 2, Table 4, and FIG.
（比較例３）
（シリカゲルの合成）
＜ゲル化工程＞
ＳｉＯ２／Ｎａ２Ｏ（モル比）＝３の珪酸ナトリウム（ＪＩＳ ３号）水溶液（ＳｉＯ２濃度１０％）に、１２％濃度の硫酸水溶液を、２０℃で添加して、ｐＨ１１のゾルを形成させた。次いで、該ゾルを、２０℃で２０分間放置し、ゲル化させ、熟成前シリカヒドロゲルを得た。次いで、得られた熟成前シリカヒドロゲルを、５〜１０ｍｍ程度に粉砕した。
＜熟成工程＞
次いで、得られた熟成前シリカヒドロゲルを水に加え、硫酸と、硫酸鉄（酸化鉄換算で、酸化珪素１００質量部に対して３質量部）とを水溶液にして添加して、ｐＨを１．４に調節し、３５℃で９０分間加熱し、熟成した。熟成後、ろ過して、熟成シリカヒドロゲルを得た。
＜乾燥工程＞
次いで、得られた熟成シリカヒドロゲルを、１１０℃で１５時間乾燥し、シリカゲルを得た。
（シリカゲルの評価）
実施例１と同様の方法で行った。その結果を、表２、表４及び図８に示す。
(Comparative Example 3)
(Synthesis of silica gel)
<Gelification process>
A 12% sulfuric acid aqueous solution is added at 20 ° C. to a sodium silicate (JIS 3) aqueous solution (SiO 2 concentration 10%) having a SiO 2 / Na 2 O (molar ratio) = 3 to form a sol having a pH of 11 I let you. Next, the sol was allowed to stand at 20 ° C. for 20 minutes to be gelled to obtain a silica hydrogel before aging. Next, the obtained pre-ripening silica hydrogel was pulverized to about 5 to 10 mm.
<Aging process>
Next, the pre-ripening silica hydrogel thus obtained was added to water, and sulfuric acid and iron sulfate (3 parts by mass with respect to 100 parts by mass of silicon oxide in terms of iron oxide) were added as an aqueous solution. 4 and heated at 35 ° C. for 90 minutes to age. After aging, filtration was performed to obtain an aged silica hydrogel.
<Drying process>
Subsequently, the obtained matured silica hydrogel was dried at 110 ° C. for 15 hours to obtain silica gel.
(Evaluation of silica gel)
The same method as in Example 1 was used. The results are shown in Table 2, Table 4, and FIG.
（比較例４〜６）
市販のＡ形シリカゲルを用意した。
比較例４：東海化学工業所社製Ａ形シリカゲル
比較例５：旭硝子エスアイテック社製Ａ形シリカゲル
比較例６：豊田化工社製Ａ形シリカゲル
（シリカゲルの評価）
実施例１と同様の方法で行った。その結果を、表２、表４及び図９に示す。
(Comparative Examples 4-6)
Commercially available A-type silica gel was prepared.
Comparative Example 4: A-type silica gel manufactured by Tokai Chemical Industry Co., Ltd. Comparative Example 5: A-type silica gel manufactured by Asahi Glass S-Tech Co., Ltd. Comparative Example 6: A-type silica gel manufactured by Toyoda Chemical Co., Ltd. (evaluation of silica gel)
The same method as in Example 1 was used. The results are shown in Table 2, Table 4, and FIG.
これらの結果から、実施例１〜５で得られたシリカゲルでは、細孔直径が２．５ｎｍ以下の領域に細孔分布のピーク（最大値）が存在していた。また、細孔直径が２〜５ｎｍの小さな細孔と、細孔直径が５ｎｍ以上の大きな細孔の両方を含む細孔構造を有していた。実施例１で得られたシリカゲルは、低湿度下（ＲＨ５０％以下）ではＡ形シリカゲルと同等の吸湿率であり、また、高湿度下（ＲＨ９０％）ではＢ形シリカゲルと同等の吸湿率であった。 From these results, the silica gel obtained in Examples 1 to 5 had a peak (maximum value) of pore distribution in a region where the pore diameter was 2.5 nm or less. Moreover, it had a pore structure including both small pores having a pore diameter of 2 to 5 nm and large pores having a pore diameter of 5 nm or more. The silica gel obtained in Example 1 has a moisture absorption rate equivalent to that of A-type silica gel under low humidity (RH 50% or less), and a moisture absorption rate equivalent to that of B-type silica gel under high humidity (RH 90%). It was.
一方、比較例１で得られたシリカゲルでは、測定領域では細孔分布のピーク（最大値）が観察されなかったが、得られた細孔分布曲線から、細孔直径が２．５ｎｍ以下の領域に細孔分布のピーク（最大値）が存在することは明らかである。また、細孔直径が２〜５ｎｍの小さな細孔と、細孔直径が５ｎｍ以上の大きな細孔の両方を含む細孔構造を有していたものの、実施例１で得られたシリカゲルに比べ、細孔直径が５ｎｍ以上の大きな細孔が少なく、全細孔容積が小さく、高湿度下（ＲＨ９０％）での吸湿率が低かった。 On the other hand, in the silica gel obtained in Comparative Example 1, the peak (maximum value) of the pore distribution was not observed in the measurement region, but the pore diameter was 2.5 nm or less from the obtained pore distribution curve. It is clear that there is a peak (maximum value) of pore distribution in. Moreover, although it had a pore structure including both small pores having a pore diameter of 2 to 5 nm and large pores having a pore diameter of 5 nm or more, compared with the silica gel obtained in Example 1, There were few large pores having a pore diameter of 5 nm or more, the total pore volume was small, and the moisture absorption rate under high humidity (RH 90%) was low.
比較例２で得られたシリカゲルでは、細孔直径が２．５ｎｍ以下の領域には細孔分布のピーク（最大値）は存在しなかった。また、細孔直径が２〜５ｎｍの小さな細孔と、細孔直径が５ｎｍ以上の大きな細孔の両方を含む細孔構造を有していたものの、実施例１で得られたシリカゲルに比べ、細孔直径が５ｎｍ以上の大きな細孔が多過ぎ、全細孔容積も大き過ぎ、低湿度下（ＲＨ５０％以下）での吸湿率が低かった。 In the silica gel obtained in Comparative Example 2, there was no peak (maximum value) of pore distribution in the region where the pore diameter was 2.5 nm or less. Moreover, although it had a pore structure including both small pores having a pore diameter of 2 to 5 nm and large pores having a pore diameter of 5 nm or more, compared with the silica gel obtained in Example 1, There were too many large pores having a pore diameter of 5 nm or more, the total pore volume was too large, and the moisture absorption rate under low humidity (RH 50% or less) was low.
比較例３で得られたシリカゲル及び比較例４〜６のシリカゲルでは、測定領域では細孔分布のピーク（最大値）が観察されなかったが、得られた細孔分布曲線から、細孔直径が２．５ｎｍ以下の領域に細孔分布のピーク（最大値）が存在することは明らかである。また、細孔直径が５ｎｍ以上の大きな細孔は、ほとんどなく、実施例１で得られたシリカゲルに比べ、高湿度下（ＲＨ９０％）での吸湿率が低かった。 In the silica gel obtained in Comparative Example 3 and the silica gels in Comparative Examples 4 to 6, the peak (maximum value) of the pore distribution was not observed in the measurement region. From the obtained pore distribution curve, the pore diameter was It is clear that a peak (maximum value) of pore distribution exists in a region of 2.5 nm or less. Further, there were almost no large pores having a pore diameter of 5 nm or more, and the moisture absorption rate under high humidity (RH 90%) was low as compared with the silica gel obtained in Example 1.
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| JP3305602B2 (en) * | 1996-12-05 | 2002-07-24 | ニチアス株式会社 | Manufacturing method of dehumidifying element |
| JP2002274835A (en) * | 2001-03-21 | 2002-09-25 | Keio Gijuku | Porous silica foam and method for producing the same |
| US7377965B2 (en) * | 2005-06-20 | 2008-05-27 | J.M. Huber Corporation | Air filtration media comprising metal-doped silicon-based gel materials |
| KR100803938B1 (en) | 2006-12-13 | 2008-02-18 | 한국화학연구원 | Mesoporous silica material for adsorbent of water in low temperature |
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| JP2010001197A (en) | 2010-01-07 |
| KR101612548B1 (en) | 2016-04-14 |
| KR20090133092A (en) | 2009-12-31 |
| CN101613109A (en) | 2009-12-30 |
| CN101613109B (en) | 2014-02-26 |
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