JPH11156141A - Drying agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fully demonstrate the hygroscopic capacity of a wrapped substance and the moisture absorbing speed of the substance by defining the weight of a mixture to be wrapped within a specified range per unit of the surface area of a package formed on the surrounding of the mixture. SOLUTION: Sepioleite in a mixture constituting this drying agent is a base having a hygroscopic capability and water retaining capability owing to a large number of hollow voids existing in the crystal structure of the Sepiolite. Both calcium chloride and magnesium chloride in the mixture exhibit high hygroscopic property and deliquescence by absorbed water. Further, magnesium oxide reacts on the deliquescenced solution of calcium chloride and magnesium chloride to form a solidified hydraulic body. Furthermore, silicon dioxide is added to suppress the solidifying body. As another essential constituent of the drying agent, a moisture-transmissive and water-proofing wrapping material is used for wrapping the mixture. The weight of the mixture to be wrapped is controlled to be within about 0.03-0.55 g/cm<2> inner surface area of the wrapping material wrapping the object mixture to be wrapped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a desiccant comprising a deliquescent salts-loaded composite dry substance and a packaging material for packaging the same.

[0002]

2. Description of the Related Art Calcium chloride, magnesium chloride, silica gel,
Zeolite and the like. Of these, chlorides of alkaline earth metals, such as calcium chloride, have a greater moisture absorption capacity than physically hygroscopic dry substances, such as zeolites, but because they are deliquescent salts, they themselves tend to dissolve in moisture-absorbed water. In order to make it a desiccant that can be used in a wide range of applications, it is necessary to carry it on a water retention agent such as a porous mineral or a water-absorbing polymer to form a composite, and to accumulate and fix the deliquescent liquid generated by the moisture absorption water in the water retention agent there were. However, due to the effect of the water retention agent, such deliquescent salts-carrying composite desiccant tends to have a small moisture absorption capacity under low humidity, and the moisture absorption water accumulated in the water retention agent leaks when an external force is applied. It was easy. As a desiccant which has solved this problem, there is known a deliquescent salt-carrying composite desiccant in which calcium chloride and / or magnesium chloride are supported in a state of dense contact between fibrous sepiolite. (Japanese Patent No. 2131494)
This is the one that maintains the excellent hygroscopic capacity of deliquescent salts, while keeping the hygroscopic water firmly mainly in sepiolite, and has a stable hygroscopic capacity without lowering the hygroscopic capacity under low humidity. And can withstand a wider range of usage conditions.

[0003] As described above, the deliquescent salts-carrying composite desiccant is an excellent desiccant, but when the moisture-absorbing water exceeds the moisture-absorbing capacity limit, the whole tends to be in a slurry state. Almost everything goes into solution.
For this reason, in actual use, it is common to install the desiccant in a dedicated water-tight container in advance, or to seal and package with a moisture-permeable water-proof film to prevent the liquid from flowing out during use. is there. In order to prevent the solution from leaking out, it is better to install it in a robust water-tight container, but it is not limited to the installation location, and it can be carried, loaded or installed without touching the drug or solution directly to the human body. The desiccant which is hermetically packaged is easier to handle because it has a certain degree of freedom in shape and the like. However, a desiccant made by integrating the moisture-absorbing / water-retentive substance and the packaging material covering the same may damage the package by external force or a sharp object. Could be spilled.
As a desiccant that minimizes the liquefaction phenomenon due to the deliquescent after moisture absorption, a composite desiccant consisting of a mixture containing sepiolite, calcium chloride, magnesium chloride, magnesium oxide, and silicon dioxide has been developed by the present inventors. ing. This composite desiccant starts to gradually cure due to the action of the hydraulic component contained as the moisture absorption water increases, suppresses the progress of liquefaction, and can maintain a substantially solid state even when the moisture absorption limit is reached. . However, in situations where rapid moisture absorption proceeds under high humidity, the progress of curing is delayed,
Depending on the degree of difference, there is a possibility that fluidized state or uncured moisture may be present, so that the possibility of these outflows is prevented in advance, and from the viewpoint of handleability, the composite desiccant is subjected to moisture permeability and water shielding. It is good to wrap with materials.

[0004]

However, in the case where the above-mentioned composite desiccant is packaged with a moisture-permeable and water-blocking material, the surroundings of the hygroscopic substance are covered with the packaged material, which hinders the composite drying agent. In some cases, for example, when the surface of the moisture-absorbing substance is in close contact with the packaging material at low humidity, the moisture absorption rate decreases, and the maximum moisture absorption rate and maximum In some cases, the amount of absorbed moisture also decreased.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a mixture mainly composed of sepiolite, calcium chloride and magnesium chloride was used as a substance for absorbing and retaining water, and this was used as a substance for retaining water. In a desiccant packaged with a packaging material such as a moisture-permeable and water-permeable sheet having 1. The moisture absorption rate and moisture absorption rate of the desiccant greatly depend on the packaging condition. Among the factors relating to the packaging state, in particular, the relationship between the total inner surface area of the package formed of the packaging material and the total weight of the mixture as the moisture-absorbing substance is determined by the relationship between the package and the mixture as the moisture-absorbing substance. 2. It has a great effect on the hygroscopic ability of the integrated desiccant. Obtained that the relationship between the total weight of the mixture and the total internal surface area of the package, which affects the moisture absorption ability, changes depending on the type of the mixture, and the weight of the packaged object per unit area of the package inner surface is determined. By adjusting the value to an optimum value according to the type of the packaged object, a desiccant capable of sufficiently exhibiting the hygroscopic property inherent in the hygroscopic substance of the packaged object was obtained.

That is, the present invention provides the following (1) to (4).
Related to the desiccant. (1) sepiolite, calcium chloride, magnesium chloride, magnesium oxide,
A desiccant comprising a mixture containing silicon dioxide and a moisture-permeable and water-permeable packaging material for packaging the same, wherein the weight of the mixture to be packaged is such that the weight of the inner surface of the package formed by the packaging material around the mixture is reduced. About 0.03 g / cm ² per unit area
A desiccant characterized by being about 0.55 g / cm ² .
(2) The above (1), wherein the sepiolite is in the form of a fiber.
Desiccant. (3) The above (1) wherein the silicon dioxide is amorphous.
Or the drying agent according to any of (2). (4) The weight of the mixture packaged with the moisture-permeable and water-proof packaging material is about 0.07 g per unit area of the inner surface of the package formed around the mixture by the packaging material.
The desiccant according to any one of the above (1) to (3), wherein the desiccant is from about 0.5 g / cm ² to about 0.55 g / cm ² .

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Sepiolite in a mixture constituting a desiccant according to the present invention is a natural mineral mainly composed of fibrous crystals having a large number of hollow holes communicating with each other in a crystal structure, and the hollow holes are formed of a physical mineral. It has a basic moisture absorbing ability and water retention ability. The sepiolite raw material used in the present invention generally uses a crushed or crushed sepiolite mineral, and its shape may be close to granular, but preferably a sufficient water retention capacity between crystals can be expected, Further, it is preferable to use a fibrous material having excellent rheological properties. In this case, the fiber length is 1 to 1000 μm,
Desirably, the thickness is about 1 to 200 μm, since more excellent results are easily obtained in terms of the mixing effect at the time of preparing the mixture and the expression of the water retention ability. The content of sepiolite in the mixture is 40 to 55 parts by weight when the mixture is 100 parts by weight. If the content of sepiolite is less than 40 parts by weight, the water retention capacity is insufficient, and if it exceeds 55 parts by weight, the moisture absorption rate becomes slow and the moisture absorption capacity becomes small, so neither is preferable.

[0008] Calcium chloride and magnesium chloride in the mixture constituting the present desiccant are both hygroscopic components that exhibit extremely high hygroscopicity, and are deliquescent inorganic salts that have deliquescent properties with hygroscopic water. In the present invention, it is desirable to use a powdery anhydride in any case. The content of calcium chloride in the mixture of 100 parts by weight is 15 to 25 parts by weight, and the content of magnesium chloride is also 15 to 25 parts by weight. In any case, if the content is less than 15 parts by weight, the moisture absorption rate at the initial stage of moisture absorption becomes slow, and the moisture absorption capacity becomes small, which is not preferable.
On the other hand, if the content exceeds 25 parts by weight, a large amount of deliquescent liquid is generated due to moisture absorption, and the desiccant may be fluidized.

The magnesium oxide in the mixture constituting the desiccant reacts with calcium chloride and magnesium chloride deliquor by absorption to form a hydraulic hardened product. The magnesium oxide used in the present invention is preferably calcined or lightly calcined magnesia having higher activity than the periclase type having high crystallinity. The magnesium oxide content in 100 parts by weight of the mixture is 5 to 20 parts by weight. If the amount is less than 5 parts by weight, the amount of the deliquescent liquid as a curing component is insufficient to compensate for the deliquescent generated, and the desiccant may be fluidized by the excess deliquescent that has not contributed to the curing reaction. On the other hand, if the content exceeds 20 parts by weight, the progress of curing becomes too remarkable, and the moisture absorption capacity may be reduced, which is not preferable.

Furthermore, silicon dioxide in the mixture constituting the present desiccant is inherently hygroscopic, but in the present invention, it is blended mainly to give an effect of suppressing hardening bonds. The structure may be either crystalline silica or amorphous, but amorphous is preferred in order to prevent a sudden solidification and to achieve a more gradual hardened state. The content of silicon dioxide in 100 parts by weight of the mixture is 3 to 15 parts by weight. If the amount is less than 3 parts by weight, the curing may proceed remarkably, and if the amount exceeds 15 parts by weight, the curing retardation and the strength of the cured body are reduced, and the handling property is sometimes unfavorable.

The mixture constituting the desiccant of the present invention has a basic structure of a composite having a structure in which a deliquescent inorganic salt of calcium chloride and magnesium chloride is interposed between fibrous or substantially granular sepiolite powders. In order to stably retain the moisture absorbed by the deliquescent inorganic salt in the sepiolite, a structure in which the sepiolite and the deliquescent inorganic salt are kept in close contact with each other, together with the magnesium oxide and silicon dioxide particles It is desirable that it is dispersed in the deliquescent inorganic salt. Incidentally, in the mixture constituting the present desiccant, even if it is a component other than the above-described components such as indicators such as indicators for sensing the moisture absorption state, the moisture absorption capacity and solidification state originally possessed by the complex In a range of component types and amounts that do not have a noticeable effect on the

The essential components of the desiccant are as follows:
There is a moisture-permeable and water-blocking packaging material for packaging the mixture, and this packaging can supplement the water retention capacity of the liquid against surplus water and deliquescent liquid that occurs when the mixture exceeds the water retention capacity and curing capacity, and the curing process When the mixture is fluidized in the inside, it is useful for preventing the mixture from flowing out and for improving the handleability as a desiccant. As the material of the moisture-permeable and water-permeable packaging material, any material may be used as long as it is a well-known moisture-permeable and water-permeable polymer compound, but a sheet-like material having flexibility and high tensile strength is desirable.

Regarding the amount of the packaging material used and the packaging form,
By adjusting the inner surface area of the package covering the mixture according to the amount of the mixture to be packaged, the moisture absorption capacity of the mixture containing sepiolite, calcium chloride and magnesium chloride as the main moisture absorbing components is almost reduced. It can be sufficiently expressed without causing the expression. That is, the amount of the mixture per unit area of the inner surface of the package formed by the packaging material around the mixture may be adjusted to an appropriate value. 0.03 g / cm ² to about 0.2 g / cm ² per unit area of the inner surface of the package.
55 g / cm ² . When the weight per unit surface area is less than about 0.03 g / cm ² , the absolute value of the moisture absorption capacity becomes small, and the volume ratio of the void portion occupying in the package increases. If the weight exceeds about 0.55 g / cm ² , the object to be packaged adheres tightly to the inner surface of the package and the moisture permeability of the packaging material cannot be sufficiently utilized. It is not preferable because the moisture absorbing ability under the humidity may be reduced. The amount of the packaged articles is subjected to packaging, and more preferably, increased stability of the packaging to the weight of about per unit area 0.07 g / cm ² ~ about 0.45 g / cm ² is more, In addition to improving the handling properties during transportation and installation, it can lead to higher moisture absorption efficiency under all humidity environments. The method of packaging the mixture to be packaged is not particularly limited.For example, a bag-like package having a rectangular or square surface having at least one open end is prepared in advance, and a predetermined amount of packaged It is easiest and most recommended to seal the open end of the package after the product is homogeneously filled using a vibrator or the like. The desiccant of the present invention is obtained by packaging the mixture with such a moisture-permeable and water-proof packaging material.

[0014]

EXAMPLES Example 1 Anhydrous magnesium chloride 4 was added to 100 parts by weight of dry sepiolite powder having an average fiber length of 200 μm, which was crushed into a fiber by a pulverizer.
6.5 parts by weight, anhydrous sodium chloride 39.8 parts by weight, calcined magnesia 25.2 parts by weight, amorphous silicon dioxide 9.7
Parts by weight (all commercially available powders having a particle size of 100 μm or less) were blended and mixed for about 1 minute with a household mixer. Using a commercially available non-woven fabric laminated with moisture-permeable synthetic paper, the obtained mixture is formed into a bag having a total inner surface area of 416 cm ² , one side having a dimension of about 13.0 cm and a width of about 16.0 cm, and having a substantially rectangular shape. The inside was filled with each of the weights shown in Table 1 and degassed and sealed. This was placed in a thermo-hygrostat kept at a temperature of 30 ° C. and a humidity of 90%, left for 24 hours or 15 days, respectively, taken out of the device, and the moisture absorption rate (%) and moisture absorption (g) of the bag contents , And the state of the contents of the bag. The results are also shown in Table 1.

[0015]

[Table 1]

Example 2 A mixture prepared in the same manner as in Example 1 was prepared using a commercially available moisture-permeable synthetic paper laminated with a nonwoven fabric, the total inner surface area was 140 cm ² , and the size of one side was about 6 cm in length. Each bag described in Table 2 was filled into a bag having a substantially rectangular shape having a width of about 11.7 cm and a width of about 11.7 cm, and the bag was evacuated and sealed. This is at a temperature of 30 ° C and a humidity of 9
Put in a thermo-hygrostat kept at 0%, leave it for 24 hours or 15 days respectively, take it out of this device, moisture absorption rate (%), moisture absorption (g) of bag contents, and state of bag contents Was examined. The results are also shown in Table 2.

[0017]

[Table 2]

[0018]

EFFECT OF THE INVENTION The desiccant according to the present invention has an excellent water retention capacity, and also has a moisture absorption capacity, which is inherent in the hygroscopic capacity of a hygroscopic substance composed of a complex of sepiolite and calcium chloride and magnesium chloride which constitute the packaged material. It is possible to sufficiently exhibit a moisture absorption rate. Further, it is excellent in handling properties in transportation and installation.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Koichi Hosogai 2-14-1, Nishishinbashi, Minato-ku, Tokyo Inside Chichibu Noda Co., Ltd.

Claims (4)

[Claims] 1. A desiccant comprising a mixture containing sepiolite, calcium chloride, magnesium chloride, magnesium oxide and silicon dioxide and a moisture-permeable and water-proof packaging material for packaging the mixture, wherein the weight of the mixture to be packaged is drying agent, characterized in that the packaging material is about 0.03 g / cm ² ~ about 0.55 g / cm ² per unit area of the package in the surface formed by around the mixture. 2. The desiccant according to claim 1, wherein the sepiolite is in a fiber form. 3. The desiccant according to claim 1, wherein the silicon dioxide is amorphous. 4. The weight of the mixture packaged in the moisture-permeable and water-permeable packaging material is from about 0.07 g / cm ² to about 0.45 per unit area of the inner surface of the package formed by the packaging material around the mixture.
Drying agent according to any one of claims 1 to 3, characterized in that a g / cm ^2.