JPH1111939A - Production of alumina based moisture regulating material - Google Patents
Production of alumina based moisture regulating materialInfo
- Publication number
- JPH1111939A JPH1111939A JP9177802A JP17780297A JPH1111939A JP H1111939 A JPH1111939 A JP H1111939A JP 9177802 A JP9177802 A JP 9177802A JP 17780297 A JP17780297 A JP 17780297A JP H1111939 A JPH1111939 A JP H1111939A
- Authority
- JP
- Japan
- Prior art keywords
- humidity
- aluminum hydroxide
- humidity control
- control material
- adsorption
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、アルミナ系調湿材
料の製造方法に関し、特に水酸化アルミニウムの熱処理
によって形成される細孔の吸放湿特性を利用することに
より、結露やカビ・ダニの発生を防止する建築材料とし
て有用なアルミナ系調湿材料の製造方法に関する。な
お、本明細書において調湿材料とは、吸湿機能及び放湿
機能を有し、例えば本発明の調湿材料を壁材として用い
た場合に、室内の湿度が高くなると水蒸気を吸収して貯
え（吸湿）、逆に環境湿度が低くなると保有する水分を
室内に放出し（放湿）、室内の湿度を一定に保つような
機能を有する微多孔質材料をいう。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an alumina-based humidity control material, and more particularly to a method for producing dew condensation and mold and mite by utilizing the moisture absorption / release characteristics of pores formed by heat treatment of aluminum hydroxide. The present invention relates to a method for producing an alumina-based humidity control material useful as a building material for preventing the generation. In addition, in this specification, the humidity control material has a moisture absorption function and a moisture release function. For example, when the humidity control material of the present invention is used as a wall material, when the indoor humidity increases, water vapor is absorbed and stored. (Moisture absorption), on the other hand, refers to a microporous material having a function of releasing the retained moisture into the room when the environmental humidity decreases (dehumidification) and keeping the indoor humidity constant.
【０００２】[0002]
【従来の技術】従来の日本の家屋では、木材や土壁等の
調湿性能の良い建築材料が用いられ、また気密性もあま
り良くないため隙間風による自然換気が行われていた。
しかし、最近の建築物では吸湿性の劣る新建材が使用さ
れ、さらに高断熱化・高気密化の促進により、以下のよ
うな問題が生じている。 （１）内部結露により建材に腐朽菌が繁殖し、強度が低
下する。 （２）ダニ・カビの繁殖によりアレルギー問題が発生す
る。 （３）梅雨時等、室内が高湿度になり易く、居住者が不
快感を感じる。 このような問題を解決するために、一般に除湿器やエア
コン等の空調設備が用いられている。しかし、設備費が
高価で、しかも快適さを保つためには常時運転しなけれ
ばならないため、運転コストも高いという難点がある。
さらに、このような空調設備を用いても、押し入れや隅
部等の局所的な場所の湿度の制御は難しいという問題が
あった。そのため、これまで種々の吸湿性能の高い調湿
建材の開発が行われてきた。2. Description of the Related Art In a conventional Japanese house, a building material having good humidity control performance such as wood or earth wall is used, and natural ventilation is performed by a draft due to poor airtightness.
However, recent buildings use new building materials with poor hygroscopicity, and further promote high insulation and high airtightness, causing the following problems. (1) Decay fungi propagate on building materials due to internal condensation, and the strength is reduced. (2) Allergy problems occur due to reproduction of mites and molds. (3) During the rainy season or the like, the interior tends to be humid, and residents feel discomfort. In order to solve such a problem, air conditioning equipment such as a dehumidifier and an air conditioner is generally used. However, there is a disadvantage that the equipment cost is high and the operation must be constantly performed in order to maintain the comfort, so that the operation cost is high.
Furthermore, there is a problem that it is difficult to control the humidity of a local place such as a closet or a corner even by using such an air conditioner. For this reason, various humidity control building materials having high moisture absorption performance have been developed.
【０００３】[0003]
【発明が解決しようとする課題】従来の調湿材料の吸着
量（吸湿量）と相対湿度の関係は、一般に図１５に示す
ような３種類のパターンに分類される。図１５におい
て、曲線Ａは、湿度の上昇とともに吸着量がほぼ比例的
に増大するパターンであり、一般にはこのような吸湿特
性を示すものが多く、その代表例はシリカゲルである。
なお、シリカゲルは、相対湿度に比例して吸着量が大き
くなるが、脱着温度は約１１０℃以上と言われており、
その放湿機能に難点がある。曲線Ｂのパターンの吸湿特
性を示すものの代表例はゼオライトであり、相対湿度が
約２０〜３０％位の低湿度で吸着量が急峻に増大する
が、それ以上は湿度が高くなってもほとんど吸着しなく
なる。最後に、曲線Ｃは、約８０〜９０％以上の高湿度
で吸着量が急峻に増大するパターンであり、そのような
吸湿特性を示す材料の例としてはカオリナイトが挙げら
れる。しかしながら、特にカビの繁殖防止の観点から
は、８０％以下の湿度で吸着量が急峻に増大する材料が
好ましい。また、快適性等の観点からは約６０％で、ま
た場合に応じては約４０％のように、所望の任意の湿度
において吸着量が急峻に増大する材料が望ましい。The relationship between the adsorption amount (moisture absorption amount) and the relative humidity of the conventional humidity control material is generally classified into three types as shown in FIG. In FIG. 15, a curve A is a pattern in which the amount of adsorption increases almost proportionally with an increase in humidity. In general, many of such patterns exhibit such moisture absorption characteristics, and a typical example is silica gel.
In addition, silica gel, the amount of adsorption increases in proportion to the relative humidity, the desorption temperature is said to be about 110 ℃ or more,
There is a drawback in its moisture release function. A typical example of the curve B showing the moisture absorption characteristic is zeolite, and the amount of adsorption increases sharply at a low relative humidity of about 20 to 30%. No longer. Finally, the curve C is a pattern in which the amount of adsorption steeply increases at a high humidity of about 80 to 90% or more, and kaolinite is an example of a material exhibiting such moisture absorption characteristics. However, in particular, from the viewpoint of preventing the growth of mold, a material whose adsorption amount increases sharply at a humidity of 80% or less is preferable. In addition, from the viewpoint of comfort and the like, a material having a steep increase in the adsorbed amount at a desired arbitrary humidity, such as about 60%, and depending on the case, about 40% is desirable.
【０００４】従って、本発明の目的は、制御された任意
の湿度で吸着量が急峻に増大する調湿材料を得ることが
でき、それによって、例えば局所的に低湿度が要求され
る場所（隅部等の結露し易い場所）においても、任意の
ほぼ一定の湿度に保つことができ、結露やカビ・ダニの
繁殖を防止することができるアルミナ系調湿材料を生産
性よく低コストで製造できる方法を提供することにあ
る。Accordingly, it is an object of the present invention to obtain a humidity control material having a steep increase in the amount of adsorption at an arbitrary controlled humidity, thereby making it possible to obtain, for example, a locally required low humidity (corner). (A part where dew condensation is likely to occur), it is possible to maintain an almost constant humidity, and to produce an alumina-based humidity control material that can prevent dew condensation and propagation of mold and mite with good productivity and low cost. It is to provide a method.
【０００５】[0005]
【課題を解決するための手段】前記目的を達成するため
に、本発明の第１の態様によれば、水酸化アルミニウム
粉末を減圧雰囲気下で熱処理することを特徴とするアル
ミナ系調湿材料の製造方法が提供される。本発明の第２
の態様によれば、平均粒径が５０μｍ以下の水酸化アル
ミニウム粉末を熱処理することを特徴とするアルミナ系
調湿材料の製造方法が提供される。さらに好適な本発明
の第３の態様によれば、平均粒径が５０μｍ以下の水酸
化アルミニウム粉末を減圧雰囲気下で熱処理することを
特徴とするアルミナ系調湿材料の製造方法が提供され
る。前記いずれの態様においても、好ましくは、前記熱
処理を３００〜８００℃の温度で行う。According to a first aspect of the present invention, there is provided an alumina-based humidity control material characterized by heat-treating aluminum hydroxide powder in a reduced-pressure atmosphere. A manufacturing method is provided. Second embodiment of the present invention
According to the aspect, there is provided a method for producing an alumina-based humidity control material, wherein an aluminum hydroxide powder having an average particle size of 50 μm or less is heat-treated. According to a further preferred third aspect of the present invention, there is provided a method for producing an alumina-based humidity control material, wherein an aluminum hydroxide powder having an average particle size of 50 μm or less is heat-treated in a reduced-pressure atmosphere. In any of the above embodiments, preferably, the heat treatment is performed at a temperature of 300 to 800C.
【０００６】[0006]
【発明の実施の形態】吸湿作用は、微多孔質材料の細孔
への水蒸気の吸着によって行われる。ケルビンの式より
明らかなように、細孔径の大きさによって、吸着量が増
大する湿度の位置が決まる。すなわち、ゼオライトのよ
うな細孔径がほぼ一定で小さい材料では、図１５の曲線
Ｂで示されるように低湿度で吸着量が増大する。また、
例えばカオリナイトの表面とその二次粒子からなる細孔
がほぼ一定で大きい材料では、図１５の曲線Ｃで示され
るように高湿度で吸着量が増大する。さらにシリカゲル
のような細孔径が幅広い分布をもつ材料では、図１５の
曲線Ａで示されるように湿度の増大とともに吸着量は単
調に増大する。そこで、希望する湿度範囲において吸着
量が急峻に増大するような調湿材料を得るためには、細
孔径を制御する必要がある。適切に細孔径を制御された
調湿材料では、環境湿度が高くなると材料の細孔に水蒸
気を水にして貯え（吸湿）、環境湿度が低くなると水を
蒸発させ（放湿）、湿度を一定の最適値に保つことがで
きる。BEST MODE FOR CARRYING OUT THE INVENTION The moisture absorbing action is carried out by the adsorption of water vapor to the pores of a microporous material. As is clear from the Kelvin equation, the position of humidity at which the amount of adsorption increases is determined by the size of the pore diameter. That is, in a material such as zeolite having a substantially constant and small pore diameter, the amount of adsorption increases at low humidity as shown by a curve B in FIG. Also,
For example, in the case of a material in which the surface of kaolinite and the pores composed of its secondary particles are substantially constant and large, the amount of adsorption increases at high humidity as shown by the curve C in FIG. Further, in a material such as silica gel having a wide distribution of pore diameters, as shown by a curve A in FIG. 15, the amount of adsorption monotonously increases with an increase in humidity. Therefore, in order to obtain a humidity control material in which the amount of adsorption steeply increases in a desired humidity range, it is necessary to control the pore diameter. With a humidity control material whose pore size is controlled appropriately, water vapor is stored in the pores of the material when the environmental humidity increases (moisture absorption), and when the environmental humidity decreases, the water evaporates (dehumidifies) and the humidity is kept constant. Can be kept at the optimum value.
【０００７】本発明者らは、上記のような吸放湿特性を
示す調湿材料を製造すべく鋭意研究の結果、調湿材料の
原料として水酸化アルミニウム（以下、水酸化アルミと
いう）の粉末を用い、これを減圧雰囲気下、好ましくは
０．９気圧以下の減圧雰囲気下で熱処理するか、あるい
は大気圧下においても、水酸化アルミ粉末の平均粒径を
５０μｍ以下に調整すれば、細孔径分布のピーク幅が狭
くてシャープな分布となり、或る一定の比較的狭い湿度
範囲で吸着量が急峻に増大する吸放湿特性を示すことを
見い出し、しかも、出発材料の水酸化アルミの平均粒径
及び／又は熱処理雰囲気の圧力、あるいはさらに熱処理
温度を変えることにより、吸着量が急峻に増大する湿度
位置を任意に変え得ることを見い出し、本発明を完成す
るに至ったものである。以下、本発明の方法による水酸
化アルミ粉末の細孔径分布及び吸放湿特性の制御に関し
て、さらに詳しく説明する。The inventors of the present invention have conducted intensive studies to produce a humidity control material having the above-described moisture absorption / desorption characteristics, and as a result, a powder of aluminum hydroxide (hereinafter referred to as aluminum hydroxide) as a raw material of the humidity control material. This is heat-treated under a reduced pressure atmosphere, preferably a reduced pressure atmosphere of 0.9 atm or less, or even under atmospheric pressure, if the average particle size of the aluminum hydroxide powder is adjusted to 50 μm or less, It has been found that the distribution has a narrow peak width and a sharp distribution, and exhibits a moisture absorption / desorption characteristic in which the amount of adsorption increases sharply in a certain relatively narrow humidity range. It has been found that by changing the diameter and / or the pressure of the heat treatment atmosphere, or the heat treatment temperature, it is possible to arbitrarily change the humidity position where the amount of adsorption steeply increases, thereby completing the present invention. That. Hereinafter, the control of the pore size distribution and moisture absorption / release properties of the aluminum hydroxide powder according to the method of the present invention will be described in more detail.
【０００８】例えば、ゼオライト、珪藻土等の天然材料
は細孔径が一義的に決まっており、その制御を行うこと
は困難である。これに対して、水酸化アルミ（ギブサイ
トＡｌ2 Ｏ3 ・３Ｈ2 Ｏ）の場合、加熱により脱水反応
が起こり、ベーマイト（Ａｌ2 Ｏ3 ・Ｈ2 Ｏ）を経てア
ルミナ（Ａｌ2 Ｏ3 ）に変化し、この過程で放出された
水の通り道（脱水経路）に細孔が生じるので、熱処理条
件を変えることにより、細孔の数及び細孔径を変化させ
ることができる。例えば、熱処理温度を変化させた場
合、２００℃で既に一部ベーマイトが生じ、３５０℃で
ギブサイトが全てベーマイトになり、５００℃以上では
アルミナになっている。従って、吸放湿に必要な細孔を
生じさせるためには、水酸化アルミ粉末の熱処理は３０
０℃以上で行うことが望ましい。熱処理温度の上昇に伴
い、脱水による細孔形成のため、粉末の比表面積は増大
するが、一方、細孔の融合も起こり始めるため、５００
℃以後は温度の上昇とともに漸次減少し、雰囲気圧力や
出発材料の平均粒径によっても若干異なるが、約７００
〜８００℃付近から急激に減少する。従って、水酸化ア
ルミ粉末の熱処理は８００℃以下で行うことが望まし
い。なお、熱処理時間は所望の吸放湿特性に応じて任意
に選定できるが、通常は数時間程度以下で充分である。For example, natural materials such as zeolite and diatomaceous earth have a unique pore size, and it is difficult to control the pore size. In contrast, when the aluminum hydroxide (gibbsite Al 2 O 3 · 3H 2 O ), occurs dehydration reaction by heating, through the boehmite (Al 2 O 3 · H 2 O) to alumina (Al 2 O 3) As a result, pores are formed in the path (dehydration path) of the water released in this process. Therefore, the number and the diameter of the pores can be changed by changing the heat treatment conditions. For example, when the heat treatment temperature is changed, some boehmite is already generated at 200 ° C., all the gibbsite becomes boehmite at 350 ° C., and becomes alumina at 500 ° C. or higher. Therefore, in order to generate pores necessary for moisture absorption and desorption, heat treatment of the aluminum hydroxide powder requires 30 minutes.
It is desirable to carry out at 0 ° C. or higher. As the heat treatment temperature rises, the specific surface area of the powder increases due to the formation of pores by dehydration.
After ℃, the temperature gradually decreases as the temperature rises, and varies slightly depending on the atmospheric pressure and the average particle size of the starting material.
It rapidly decreases from around 800 ° C. Therefore, the heat treatment of the aluminum hydroxide powder is desirably performed at 800 ° C. or less. The heat treatment time can be arbitrarily selected according to the desired moisture absorption / desorption characteristics, but usually about several hours or less is sufficient.
【０００９】吸着（吸湿）は、材料の細孔中の毛細管凝
縮作用によって起こると考えられるため、細孔の数や細
孔径によって吸着の挙動が変化する。熱処理温度と吸着
量の関係についても、熱処理温度が３００℃から５００
℃にかけて上昇するに伴い、粉末の比表面積が増大する
と共に、吸着量も大幅に上昇し、例えば大気圧下での熱
処理においては約５００℃付近の熱処理温度で吸着量は
ピークを示し、その後、熱処理温度が上昇するに伴って
比表面積が減少するため漸次減少し、約７００〜８００
℃から吸着量は急激に減少する。また、高温での熱処理
はそれだけ加熱エネルギーも必要となり、経済的にも不
利となる。このような吸着量や経済性等の観点からみ
て、より好ましい熱処理温度は３００℃以上、７００℃
以下であり、特に好ましくは４００℃以上、６００℃以
下である。また、水酸化アルミ粉末の平均粒径及び熱処
理雰囲気の圧力が同一であっても、熱処理温度によって
吸着量が急峻に増大する湿度位置（より正確には所定幅
の湿度域）が変化し、高温になる程、高湿度側に移行
し、またその湿度域における吸着量の増大度合（立ち上
がり）も急激になる。Since adsorption (moisture absorption) is considered to be caused by the capillary condensation in the pores of the material, the adsorption behavior changes depending on the number and diameter of the pores. Regarding the relationship between the heat treatment temperature and the adsorption amount, the heat treatment temperature is from 300 ° C. to 500 ° C.
As the temperature rises to 0 ° C., the specific surface area of the powder increases, and the amount of adsorption also significantly increases. For example, in the heat treatment under atmospheric pressure, the amount of adsorption shows a peak at a heat treatment temperature of about 500 ° C., The specific surface area decreases as the heat treatment temperature increases, and gradually decreases to about 700 to 800.
From ℃, the amount of adsorption decreases sharply. Heat treatment at a high temperature also requires heating energy, which is economically disadvantageous. From the viewpoints of such an adsorption amount and economic efficiency, a more preferable heat treatment temperature is 300 ° C. or more and 700 ° C.
Or less, particularly preferably 400 ° C. or more and 600 ° C. or less. Further, even if the average particle size of the aluminum hydroxide powder and the pressure of the heat treatment atmosphere are the same, the humidity position (more precisely, the humidity range of a predetermined width) at which the amount of adsorption increases sharply changes depending on the heat treatment temperature. , The humidity shifts to the high humidity side, and the degree of increase (rise) of the adsorption amount in that humidity range also becomes sharp.
【００１０】また、本発明者らの研究によれば、水酸化
アルミ粉末の熱処理による脱水反応（熱分解反応）の促
進には、減圧によって分解生成気体（水蒸気）を材料内
から除去することが効果的であることが確認された。す
なわち、熱処理雰囲気の水蒸気分圧を減少させて熱処理
することにより、細孔径を制御することができる。例え
ば、雰囲気圧力を０．９気圧以下、好ましくは０．１気
圧以下の減圧雰囲気下で熱処理した場合、細孔径分布の
ピーク幅が狭くてシャープな分布となり、その結果、熱
処理温度に応じて相対湿度が約３０〜約６０％の任意の
値で、吸着量の立ち上がりが急峻な調湿材料を得ること
ができる。また、概して雰囲気圧力が低くなる程、調湿
材料の細孔径分布のピーク幅が狭く、かつシャープなも
のとなり、また比表面積が増大し、平均細孔径が小さく
なる傾向にある。なお、熱処理を減圧雰囲気下で行う場
合、出発材料の水酸化アルミ粉末の平均粒径は多少大き
くてもよく、例えば１００μｍ以下でも吸着量の増大が
急峻な調湿材料を得ることができるが、この場合にも、
水酸化アルミ粉末の平均粒径は後述するように５０μｍ
以下であることが好ましい。According to the study of the present inventors, in order to accelerate the dehydration reaction (thermal decomposition reaction) by heat treatment of aluminum hydroxide powder, it is necessary to remove the decomposition gas (water vapor) from the material by reducing the pressure. It was confirmed to be effective. That is, the pore diameter can be controlled by performing the heat treatment while reducing the water vapor partial pressure in the heat treatment atmosphere. For example, when heat treatment is performed under a reduced pressure atmosphere of an atmospheric pressure of 0.9 atm or less, preferably 0.1 atm or less, the peak width of the pore diameter distribution becomes narrow and sharp, and as a result, the relative diameter varies depending on the heat treatment temperature. When the humidity is any value of about 30 to about 60%, a humidity control material having a steep rise in the amount of adsorption can be obtained. In general, as the atmospheric pressure becomes lower, the peak width of the pore size distribution of the humidity control material becomes narrower and sharper, the specific surface area increases, and the average pore size tends to decrease. When the heat treatment is performed in a reduced-pressure atmosphere, the average particle size of the aluminum hydroxide powder as a starting material may be somewhat large, for example, a humidity control material having a steep increase in adsorption amount even at 100 μm or less can be obtained. Again, in this case,
The average particle size of the aluminum hydroxide powder is 50 μm as described later.
The following is preferred.
【００１１】さらに本発明者らの研究によれば、大気圧
下で熱処理を行った場合においても、水酸化アルミ粉末
の平均粒径を５０μｍ以下、好ましくは２５μｍ以下、
より好ましくは２μｍ以下に調整した場合、同様の傾向
を示し、熱処理温度に応じた所定の湿度域で吸着量が急
峻に増大する調湿材料が得られることが見い出された。
また、水酸化アルミ粉末の平均粒径が小さい程、得られ
る調湿材料の吸着量は全体的に増大する。さらに、減圧
雰囲気下で、平均粒径の小さな水酸化アルミ粉末を用い
て熱処理を行うと、上記効果が助長されることは言うま
でもない。According to the study of the present inventors, the average particle size of the aluminum hydroxide powder is 50 μm or less, preferably 25 μm or less, even when the heat treatment is performed at atmospheric pressure.
More preferably, when adjusted to 2 μm or less, it has been found that a humidity control material showing the same tendency and having a steep increase in the adsorption amount in a predetermined humidity range according to the heat treatment temperature can be obtained.
In addition, the smaller the average particle size of the aluminum hydroxide powder, the greater the amount of adsorption of the obtained humidity control material. Further, it is needless to say that when the heat treatment is performed using an aluminum hydroxide powder having a small average particle diameter in a reduced pressure atmosphere, the above effect is promoted.
【００１２】以上のように、本発明の方法によれば、熱
処理温度、雰囲気圧力、水酸化アルミ粉末の粒径を変え
ることにより、得られる粉末の細孔径分布、従って吸放
湿特性を比較的に簡単に、任意に制御することができ
る。得られる粉末状のアルミナ系調湿材料は、適当なバ
インダー、補強材等を混合し、加圧成形してシート材、
板材等任意の形状に成形した固形材や、コーティング材
など、任意の形態で用いることができ、壁材等の建築用
材料に好適に利用することができる。また、所望の湿度
に応じて、適切な湿度域で吸着量が急峻に増大する調湿
材料を選択して使用することができる。例えば、換気が
困難で高湿度になり易い押し入れ、下駄箱など、局所的
に低湿度が要求される場所においても、低湿度域で吸着
量が急激に増大する調湿材料を選択使用することによ
り、任意の空間を常に任意の適切な湿度状態に保つこと
ができる。それによって、結露やカビ・ダニなどの繁殖
を防止でき、しかも、センサーや電気機器を用いていな
いため、極めて安全で経済的に調湿が行われる。As described above, according to the method of the present invention, by changing the heat treatment temperature, the atmospheric pressure, and the particle size of the aluminum hydroxide powder, the pore size distribution of the obtained powder, and thus the moisture absorption / release characteristics, can be relatively controlled. It can be easily and arbitrarily controlled. The resulting powdery alumina-based humidity control material is prepared by mixing a suitable binder, reinforcing material, and the like, pressing and molding the sheet material,
It can be used in any form, such as a solid material formed into an arbitrary shape such as a plate material or a coating material, and can be suitably used as a building material such as a wall material. Further, it is possible to select and use a humidity control material in which the amount of adsorption steeply increases in an appropriate humidity range according to a desired humidity. For example, even in places where low humidity is required locally, such as push-fits that are difficult to ventilate and are likely to become high humidity, geta boxes, etc., by selecting and using a humidity control material that adsorbs rapidly in the low humidity area , Any space can always be kept at any suitable humidity. As a result, it is possible to prevent condensation and propagation of molds and mites, and furthermore, since no sensors or electric devices are used, humidity control is performed extremely safely and economically.
【００１３】[0013]
【実施例】以下、実施例を示して本発明についてより具
体的に説明するが、本発明が下記実施例に限定されるも
のでないことはもとよりである。EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but it is needless to say that the present invention is not limited to the following examples.
【００１４】実施例１ 平均粒径約２５μｍの水酸化アルミ粉末を６００℃、
０．１気圧の減圧雰囲気下で熱処理した。熱処理は、水
酸化アルミ粉末をセラミック製緻密円筒管内に入れ、円
筒管を真空ポンプに接続して０．１気圧に維持し、これ
を環状電気炉内に設置し、熱電対で試料温度を測定しな
がら行った。昇降温速度は２００℃／ｈとし、熱処理温
度での保持時間は２時間とした。得られた粉末の細孔径
分布を図１に、またその吸放湿特性（吸着等温線）を図
２に示す。なお、得られた粉末の細孔径分布は、窒素吸
着法を用いて測定した。また、吸放湿特性は、測定系内
の温度を一定（２５℃）にして、水蒸気圧を変化させて
平衡状態に達した時の試料重量の変化から吸着量を求め
る（重量法）吸着平衡測定装置を用いて測定した。吸着
量は、絶乾状態の粉末重量に対する水の吸着重量の割合
を示す。図１から明らかなように、得られた調湿材料の
細孔径分布はピーク幅が狭くてシャープな分布であり、
また図２から明らかなように、吸着量は相対湿度約６０
％で立ち上がっている。従って、この調湿材料を用いる
ことにより、環境湿度を約６０％に調湿できる。Example 1 Aluminum hydroxide powder having an average particle size of about 25 μm was heated at 600 ° C.
Heat treatment was performed under a reduced pressure atmosphere of 0.1 atm. For heat treatment, put the aluminum hydroxide powder in a ceramic dense cylindrical tube, connect the cylindrical tube to a vacuum pump and maintain it at 0.1 atm, install it in an annular electric furnace, and measure the sample temperature with a thermocouple I went while doing. The temperature rise / fall rate was 200 ° C./h, and the holding time at the heat treatment temperature was 2 hours. FIG. 1 shows the pore size distribution of the obtained powder, and FIG. 2 shows its moisture absorption / desorption characteristics (adsorption isotherm). The pore size distribution of the obtained powder was measured using a nitrogen adsorption method. The moisture absorption / desorption characteristic is obtained by determining the amount of adsorption from a change in the sample weight when the temperature in the measurement system is kept constant (25 ° C.) and the water vapor pressure is changed to reach an equilibrium state (gravimetric method). It measured using the measuring device. The amount of adsorption indicates the ratio of the weight of water adsorbed to the weight of the powder in a completely dry state. As is clear from FIG. 1, the pore size distribution of the obtained humidity control material has a narrow peak width and a sharp distribution,
As is apparent from FIG. 2, the amount of adsorption was about 60% relative humidity.
Stands up in percent. Therefore, by using this humidity control material, the environmental humidity can be controlled to about 60%.
【００１５】実施例２ 平均粒径約２５μｍの水酸化アルミ粉末を５００℃、
０．１気圧の減圧雰囲気下で実施例１と同様に熱処理し
た。得られた粉末の細孔径分布を図３に、またその吸放
湿特性を図４に示す。図３から明らかなように、得られ
た調湿材料の細孔径分布はピーク幅が狭くてシャープな
分布であり、また図４から明らかなように、吸着量は相
対湿度約５０％で立ち上がっている。従って、この調湿
材料を用いることにより、環境湿度を約５０％に調湿で
きる。Example 2 Aluminum hydroxide powder having an average particle size of about 25 μm was heated at 500 ° C.
Heat treatment was performed in the same manner as in Example 1 under a reduced pressure atmosphere of 0.1 atm. FIG. 3 shows the pore size distribution of the obtained powder, and FIG. 4 shows its moisture absorption / release characteristics. As is clear from FIG. 3, the pore size distribution of the obtained humidity control material has a narrow peak width and a sharp distribution, and as is clear from FIG. 4, the adsorption amount rises at a relative humidity of about 50%. I have. Therefore, by using this humidity control material, the environmental humidity can be controlled to about 50%.
【００１６】実施例３ 平均粒径約２５μｍの水酸化アルミ粉末を５００℃、１
気圧の大気中で実施例１と同様に熱処理した。得られた
粉末の細孔径分布を図５に、またその吸放湿特性を図６
に示す。図５から明らかなように、得られた調湿材料の
細孔径分布はピーク幅が比較的に狭くてシャープな分布
であり、また図６から明らかなように、吸着量は相対湿
度約７０％で立ち上がっている。従って、この調湿材料
を用いることにより、環境湿度を約７０％に調湿でき
る。Example 3 Aluminum hydroxide powder having an average particle size of about 25 μm
Heat treatment was performed in the same manner as in Example 1 in an atmosphere at atmospheric pressure. FIG. 5 shows the pore size distribution of the obtained powder, and FIG.
Shown in As is clear from FIG. 5, the pore size distribution of the obtained humidity control material is a sharp distribution with a relatively narrow peak width, and as is clear from FIG. 6, the adsorption amount is about 70% relative humidity. Standing up. Therefore, by using this humidity control material, the environmental humidity can be controlled to about 70%.
【００１７】実施例４ 平均粒径約２５μｍの水酸化アルミ粉末を４００℃、１
気圧の大気中で実施例１と同様に熱処理した。得られた
粉末の細孔径分布を図７に、またその吸放湿特性を図８
に示す。図７から明らかなように、得られた調湿材料の
細孔径分布はピーク幅が狭くてシャープな分布であり、
また図８から明らかなように、吸着量は相対湿度約５０
％で立ち上がっている。従って、この調湿材料を用いる
ことにより、環境湿度を約５０％に調湿できる。Example 4 Aluminum hydroxide powder having an average particle size of about 25 .mu.m was heated at 400.degree.
Heat treatment was performed in the same manner as in Example 1 in an atmosphere at atmospheric pressure. FIG. 7 shows the pore size distribution of the obtained powder, and FIG.
Shown in As is clear from FIG. 7, the pore size distribution of the obtained humidity control material has a narrow peak width and a sharp distribution,
As is clear from FIG. 8, the amount of adsorption is about 50% relative humidity.
Stands up in percent. Therefore, by using this humidity control material, the environmental humidity can be controlled to about 50%.
【００１８】実施例５ 実施例１で用いた平均粒径約２５μｍの水酸化アルミ粉
末をボールミルで粉砕して得た平均粒径約２μｍの水酸
化アルミ粉末を６００℃、０．１気圧の減圧雰囲気下で
熱処理した。得られた粉末の細孔径分布を図９に、また
その吸放湿特性を図１０に示す。図９から明らかなよう
に、得られた調湿材料の細孔径分布はピーク幅が狭くて
シャープな分布であり、また図１０から明らかなよう
に、吸着量は相対湿度約５０％で立ち上がっている。Example 5 The aluminum hydroxide powder having an average particle size of about 2 μm obtained by grinding the aluminum hydroxide powder having an average particle diameter of about 25 μm used in Example 1 with a ball mill was reduced to 600 ° C. and 0.1 atm. Heat treatment was performed in an atmosphere. FIG. 9 shows the pore size distribution of the obtained powder, and FIG. 10 shows the moisture absorption / release characteristics. As is clear from FIG. 9, the pore size distribution of the obtained humidity control material has a narrow peak width and a sharp distribution, and as is clear from FIG. 10, the adsorption amount rises at a relative humidity of about 50%. I have.
【００１９】実施例６ 実施例５で用いた平均粒径約２μｍの水酸化アルミ粉末
を４００℃、０．１気圧の減圧雰囲気下で熱処理した。
得られた粉末の細孔径分布を図１１に、またその吸放湿
特性を図１２に示す。得られた調湿材料には微細な細孔
が含まれるため、４０％位の湿度位置で吸着量が急峻に
増大している。Example 6 The aluminum hydroxide powder having an average particle size of about 2 μm used in Example 5 was heat-treated at 400 ° C. under a reduced pressure atmosphere of 0.1 atm.
FIG. 11 shows the pore size distribution of the obtained powder, and FIG. 12 shows the moisture absorption / release characteristics. Since the obtained humidity control material contains fine pores, the amount of adsorption sharply increases at a humidity position of about 40%.
【００２０】実施例７ 平均粒径約２５μｍの水酸化アルミ粉末を６００℃、
０．０１気圧の減圧雰囲気下で実施例１と同様に熱処理
した。得られた粉末の細孔径分布を図１３に、またその
吸放湿特性を図１４に示す。図１３から明らかなよう
に、得られた調湿材料の細孔径分布はピーク幅が狭くて
シャープであり、また図１４から明らかなように、吸着
量は相対湿度約６０％で立ち上がっている。従って、こ
の調湿材料を用いることにより、環境湿度を約６０％に
調湿できる。上記各実施例から明らかなように、減圧雰
囲気下で、あるいは水酸化アルミ粉末の粒径を小さく調
整し、熱処理することにより、細孔径分布がシャープ
で、吸着量が所定の湿度位置で急峻に立ち上がる調湿材
料を得ることができ、また熱処理条件を適宜変えること
により、任意の吸放湿特性が得られるように制御するこ
とができる。Example 7 Aluminum hydroxide powder having an average particle size of about 25 μm was heated at 600 ° C.
Heat treatment was performed in the same manner as in Example 1 under a reduced pressure atmosphere of 0.01 atm. FIG. 13 shows the pore size distribution of the obtained powder, and FIG. 14 shows its moisture absorption / release characteristics. As is clear from FIG. 13, the pore size distribution of the obtained humidity control material is narrow and sharp in peak width, and as is clear from FIG. 14, the adsorption amount rises at a relative humidity of about 60%. Therefore, by using this humidity control material, the environmental humidity can be controlled to about 60%. As is clear from the above examples, under a reduced pressure atmosphere or by adjusting the particle size of the aluminum hydroxide powder to a small value and performing a heat treatment, the pore size distribution is sharp, and the amount of adsorption is sharp at a predetermined humidity position. A rising humidity control material can be obtained, and by appropriately changing the heat treatment conditions, control can be performed so as to obtain any moisture absorption / release characteristics.
【００２１】[0021]
【発明の効果】以上のように、本発明のアルミナ系調湿
材料の製造方法に従って水酸化アルミ粉末を適切に熱処
理することにより、細孔径分布を任意に制御でき、任意
の湿度で吸着量が急峻に増大する調湿材料を得ることが
できる。本発明により得られる調湿材料を適宜選択して
用いることによって、例えば局所的に低湿度が要求され
る場所（隅部等の結露し易い場所）においても、任意の
所望の湿度に保つことができ、結露やカビ・ダニの繁殖
を防止することができる。また、本発明の方法は単に熱
処理のみによるため、その工程が比較的簡単であり、従
って前記したような優れた吸放湿特性を示すアルミナ系
調湿材料を生産性良く低コストで製造することができ
る。As described above, by appropriately heat-treating aluminum hydroxide powder in accordance with the method for producing an alumina-based humidity control material of the present invention, the pore size distribution can be controlled arbitrarily, and the adsorption amount can be controlled at any humidity. A steeply increasing humidity control material can be obtained. By appropriately selecting and using the humidity control material obtained by the present invention, it is possible to maintain any desired humidity even in a place where low humidity is required locally (a place such as a corner where condensation is likely to occur). It is possible to prevent dew condensation and mold / mite breeding. In addition, since the method of the present invention is based solely on heat treatment, the process is relatively simple. Therefore, it is possible to produce an alumina-based humidity control material exhibiting excellent moisture absorption / release characteristics as described above with good productivity and low cost. Can be.
【図１】実施例１で作製したアルミナ系調湿材料の細孔
径分布を示すグラフである。FIG. 1 is a graph showing a pore size distribution of an alumina-based humidity control material produced in Example 1.
【図２】実施例１で作製したアルミナ系調湿材料の吸放
湿特性を示すグラフである。FIG. 2 is a graph showing the moisture absorption / release properties of the alumina-based humidity control material produced in Example 1.
【図３】実施例２で作製したアルミナ系調湿材料の細孔
径分布を示すグラフである。FIG. 3 is a graph showing a pore size distribution of an alumina-based humidity control material produced in Example 2.
【図４】実施例２で作製したアルミナ系調湿材料の吸放
湿特性を示すグラフである。FIG. 4 is a graph showing the moisture absorption / desorption characteristics of the alumina-based humidity control material produced in Example 2.
【図５】実施例３で作製したアルミナ系調湿材料の細孔
径分布を示すグラフである。FIG. 5 is a graph showing a pore size distribution of the alumina-based humidity control material produced in Example 3.
【図６】実施例３で作製したアルミナ系調湿材料の吸放
湿特性を示すグラフである。FIG. 6 is a graph showing the moisture absorption / release characteristics of the alumina-based humidity control material produced in Example 3.
【図７】実施例４で作製したアルミナ系調湿材料の細孔
径分布を示すグラフである。FIG. 7 is a graph showing the pore size distribution of the alumina-based humidity control material produced in Example 4.
【図８】実施例４で作製したアルミナ系調湿材料の吸放
湿特性を示すグラフである。FIG. 8 is a graph showing the moisture absorption / release characteristics of the alumina-based humidity control material produced in Example 4.
【図９】実施例５で作製したアルミナ系調湿材料の細孔
径分布を示すグラフである。FIG. 9 is a graph showing the pore size distribution of the alumina-based humidity control material produced in Example 5.
【図１０】実施例５で作製したアルミナ系調湿材料の吸
放湿特性を示すグラフである。FIG. 10 is a graph showing the moisture absorption / release properties of the alumina-based humidity control material produced in Example 5.
【図１１】実施例６で作製したアルミナ系調湿材料の細
孔径分布を示すグラフである。FIG. 11 is a graph showing a pore size distribution of the alumina-based humidity control material produced in Example 6.
【図１２】実施例６で作製したアルミナ系調湿材料の吸
放湿特性を示すグラフである。FIG. 12 is a graph showing the moisture absorption / release characteristics of the alumina-based humidity control material produced in Example 6.
【図１３】実施例７で作製したアルミナ系調湿材料の細
孔径分布を示すグラフである。FIG. 13 is a graph showing the pore size distribution of the alumina-based humidity control material produced in Example 7.
【図１４】実施例７で作製したアルミナ系調湿材料の吸
放湿特性を示すグラフである。FIG. 14 is a graph showing the moisture absorption / release characteristics of the alumina-based humidity control material produced in Example 7.
【図１５】従来の調湿材料の吸湿特性パターンを示すグ
ラフである。FIG. 15 is a graph showing a moisture absorption characteristic pattern of a conventional humidity control material.
Claims (4)
で熱処理することを特徴とするアルミナ系調湿材料の製
造方法。1. A method for producing an alumina-based humidity control material, comprising heat-treating aluminum hydroxide powder in a reduced-pressure atmosphere.
ニウム粉末を熱処理することを特徴とするアルミナ系調
湿材料の製造方法。2. A method for producing an alumina-based humidity control material, comprising heat-treating aluminum hydroxide powder having an average particle size of 50 μm or less.
ニウム粉末を減圧雰囲気下で熱処理することを特徴とす
るアルミナ系調湿材料の製造方法。3. A method for producing an alumina-based humidity control material, comprising heat-treating aluminum hydroxide powder having an average particle size of 50 μm or less under a reduced pressure atmosphere.
行う請求項１乃至３のいずれか一項に記載の方法。4. The method according to claim 1, wherein the heat treatment is performed at a temperature of 300 to 800 ° C.
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| JP17780297A JP3786230B2 (en) | 1997-06-19 | 1997-06-19 | Manufacturing method of alumina humidity conditioning material |
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| JP3786230B2 JP3786230B2 (en) | 2006-06-14 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US6615942B2 (en) | 1999-06-18 | 2003-09-09 | Kubota Corporation | Swivel type working vehicle |
| WO2007004424A1 (en) * | 2005-07-06 | 2007-01-11 | Maruishi Ceramic Materials Co., Ltd. | Method for producing ceramic porous article |
| JP2011504867A (en) * | 2007-11-30 | 2011-02-17 | ナノロジカ エービー | Method for producing nanoporous alumina material having controlled structure and particle size, and nanoporous alumina obtained by the method |
| US7927406B2 (en) | 2007-06-01 | 2011-04-19 | Denso Corporation | Water droplet generating system and method for generating water droplet |
| CN104370297A (en) * | 2014-10-27 | 2015-02-25 | 浙江理工大学 | Preparation method of aluminum oxide humidity adjusting material |
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1997
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6615942B2 (en) | 1999-06-18 | 2003-09-09 | Kubota Corporation | Swivel type working vehicle |
| WO2007004424A1 (en) * | 2005-07-06 | 2007-01-11 | Maruishi Ceramic Materials Co., Ltd. | Method for producing ceramic porous article |
| US7927406B2 (en) | 2007-06-01 | 2011-04-19 | Denso Corporation | Water droplet generating system and method for generating water droplet |
| JP2011504867A (en) * | 2007-11-30 | 2011-02-17 | ナノロジカ エービー | Method for producing nanoporous alumina material having controlled structure and particle size, and nanoporous alumina obtained by the method |
| CN104370297A (en) * | 2014-10-27 | 2015-02-25 | 浙江理工大学 | Preparation method of aluminum oxide humidity adjusting material |
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