JP2000033224A - Humidity controlling material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a humidity controlling material which demonstrates a humidity controlling function by absorbing moisture from an atmosphere when humidity is high and releasing the stored moisture when humidity is low. SOLUTION: An outer shell layer 2 in which pores 3 are formed in the surface of a deliquescent inorganic salt (or its solution) 1 is formed. Resins or waxes are not limited in particular to form the shell layer 2, and polystyrene and poly(methyl methacrylate) can be used. Especially, polystyrene is desirable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a humidity control material which stores humidity when the humidity is high and releases the stored humidity when the humidity decreases, thereby exhibiting a humidity control function.

[0002]

[0005] In a concrete building such as a building or an apartment, as well as a wooden building such as a general home, temperature control air conditioning is performed by an air conditioner or the like. Humidity adjustment is also required. For example, if the humidity is excessive or the temperature difference between the outside air and the room is large, dew condensation occurs on the window glass or the wall, and mold and the like are liable to breed, which also causes deterioration of the living environment. On the contrary, if the room air is excessively dried, the skin may be dried, or the mucous membrane may be dried to easily catch a cold or the like. As described above, it is desirable that the human living environment is within a moderate humidity range.

[0003] For this reason, it has been the current practice to adjust the humidity using a humidifier or a dehumidifier, but such a dehumidifier and a humidifier have various problems. That is, in the case of the dehumidifier, the dehumidifying function cannot be exhibited unless the temperature is high to some extent, and thus is not suitable for the winter season or the like. Further, the humidifier has a problem that dew condensation easily occurs on a wall or the like. Furthermore, humidifiers and dehumidifiers are used only in limited places, and currently have little effect locally such as bathrooms and window frames.
Furthermore, if there is a material that can expect both the dehumidifying effect and the humidifying effect, it is convenient without having to use two different types of devices. Therefore, it has been practiced to absorb moisture in the atmosphere as moisture by using a moisture absorbing material such as natural cellulosic material, but these materials only absorb moisture and are suitable for releasing this absorbed moisture. There was no problem.

The present invention has been made on the basis of the above-mentioned problems, and is a humidity control material which exhibits a humidity control function by absorbing humidity from the atmosphere when the humidity is high and releasing the stored humidity when the humidity decreases. The purpose is to provide.

[0005]

Means for Solving the Problems As a result of intensive studies in view of the above-mentioned object, the present inventors have found that while deliquescent inorganic salts have a rapid response to the humidity in the air, they readily dissolve themselves as they are. However, it has been found that if this is included in the microcapsules in the form of fine particles, moisture can be repeatedly and rapidly absorbed and discharged through the microcapsules, and further, can be applied to various uses. . The present inventors furthermore, a solution of deliquescent inorganic salts,
In particular, it has been found that when the solution is microencapsulated as a highly concentrated solution, the deliquescent inorganic salts can be easily microencapsulated. The present invention has been made based on these.

That is, the humidity control material of claim 1 of the present invention comprises microcapsules containing deliquescent inorganic salts.

[0007] In a second aspect of the present invention, in the humidity adjusting material, the microcapsules have fine pores.

[0008] In a third aspect of the present invention, there is provided the humidity control material according to the first or second aspect, wherein two or more kinds of microcapsules having different thicknesses of capsule walls and different pore diameters are used.

Further, the humidity control material according to claim 4 is the one according to any one of claims 1 to 3, wherein the deliquescent inorganic salts are contained in a microcapsule as a solution.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the humidity adjusting material of the present invention will be described in detail.

The deliquescent inorganic salts used in the present invention include potassium carbonate, zinc chloride, calcium chloride, iron chloride (hexahydrate), cupric chloride, magnesium chloride (hexahydrate), copper nitrate, Potassium hydroxide, sodium hydroxide, sodium nitrate and the like can be used, and calcium chloride is particularly preferable. Such deliquescent inorganic salts are:
An aqueous solution can be used depending on the hygroscopicity and the moisture release.

As shown in FIG. 1, such a microcapsule has a structure in which an outer shell layer 2 having micropores 3 is formed on the surface of a deliquescent inorganic salt (or a solution thereof) 1. The resin or wax for forming the outer shell layer 2 is not particularly limited, and polystyrene, methyl methacrylate polymer, or the like can be used, and polystyrene is particularly preferable.

The above-mentioned microcapsules can be produced by a conventional method, for example, by a submerged drying method or an interfacial polycondensation method. Specifically, when the outer shell layer 2 is made of polystyrene, it can be manufactured by the following in-liquid drying method. First, polystyrene forming the outer shell layer 2 is dissolved in a volatile solvent such as dichloromethane to prepare a polystyrene solution. The concentration of this polystyrene solution is preferably 5 to 20% by weight with the total of polystyrene + solvent being 100% by weight. When the amount of polystyrene is less than 5% by weight, the outer shell layer 2 to be formed becomes too thin, and it becomes difficult to form a complete outer shell layer 2.
If it exceeds 20% by weight, the concentration becomes too high, and the solution tends to be non-uniform, and the homogeneity of the obtained microcapsules decreases. A surfactant such as sorbitan can be added to this polystyrene solution as needed.

Next, the above-described solution of the deliquescent inorganic salt is dispersed in the polystyrene solution to form a film of the solution of the deliquescent inorganic salt on the surfaces of the particles of the solution. At this time, by stirring the polystyrene solution with a stirrer or the like, the solution of the deliquescent inorganic salt can be made into particles, and the average particle size can be appropriately adjusted by the stirring speed. Thereafter, the particles of the deliquescent inorganic salts are taken out of the polystyrene solution and put into water. Preferably, about 0.5% by weight of a water-soluble polymer such as polyvinyl alcohol is dissolved in the water for stabilization. When the particles of the deliquescent inorganic salts having a film formed of a polystyrene solution on the surface are immersed in water, only dichloromethane, which is a solvent, is removed from the film. Microcapsules as shown can be obtained.

The microcapsules of the deliquescent inorganic salt obtained as described above can have various moisture absorbing properties by adjusting the production conditions. For example, if the concentration of the polystyrene solution is reduced, the outer shell layer 2 is formed thinner and the micropores 3 are formed more. The lower concentration is a microcapsule (first microcapsule) in which the outer shell layer 2 is thinner and the ratio of the micropores 3 is large, and the higher concentration of the polystyrene solution is thicker in the outer shell layer 2 and the ratio of the micropores 3 is small. The number of microcapsules (second microcapsules) is reduced. For this reason, the first microcapsules can absorb and release moisture more quickly than the second microcapsules, have high sensitivity to humidity, and perform moisture absorption / release at lower humidity. . Also, the second
Microcapsules, on the contrary, absorb and release moisture at a higher humidity. In addition, in the obtained microcapsules, a solution of the deliquescent inorganic salts will be present at first, but after that, heat treatment is performed to evaporate the water of the salt solution therein to precipitate the salts or to reduce the concentration thereof. By adjusting, the moisture absorption / desorption performance can also be adjusted. Therefore, by combining these microcapsules having different moisture absorption performances, the function of humidity adjustment can be controlled.

The size and ratio of the micropores 3 are not limited to the concentration of the polystyrene solution, but are changed by adjusting the volatilization rate of dichloromethane as a solvent by changing the temperature of water to be immersed in the polystyrene solution. You can also. The resin component constituting the outer shell layer 2 includes:
Use microcapsules made of other resin components, since polyolefins such as polypropylene and polyethylene and other various resin components can be used as long as they are soluble in a solvent (not containing water) instead of polystyrene. Thereby, microcapsules having different moisture absorption performance can be obtained. In the above description, the case where dichloromethane was used as the solvent was described. However, as long as the resin constituting the outer shell layer 2 can be dissolved, another solvent such as another organic solvent or limonene (excluding water) is used. ) Can be used.

The particle size of the microcapsules obtained in this manner can be appropriately adjusted depending on the stirring conditions when the solution of the deliquescent inorganic salt is dispersed in the polystyrene solution, but is generally from 10 μm to 1 mm, preferably from 10 μm to 1 mm. 100μ
m to 1 mm. Further, the size of the fine holes 3 can be appropriately adjusted according to the manufacturing conditions, but is 0.01 to 0.09 μm.
It is about.

The sensitivity of the microcapsules containing the deliquescent inorganic salts described above to moisture absorption and desorption can be appropriately adjusted according to the state of the deliquescent inorganic salts in the microcapsules. In other words, if the deliquescent inorganic salts contained in the microcapsules are in a dry state, they absorb moisture quickly even at very low humidity, but if the deliquescent inorganic salts are in a dilute aqueous solution, the reverse is true. Easily release moisture. Practically, the humidity is in the range of 30 to 80% RH, especially 4%.
Preferably, it has a sensitivity in the range of 0 to 70%. The amount of moisture absorption (release) depends on the particle size of the microcapsules, but is about 1 to 10 g per 1 g of the microcapsules.

The humidity control material of the present invention as described above comprises:
Two or more kinds of microcapsules having different hygroscopic performances can be mixed and used in an arbitrary ratio depending on the intended use and use environment. For example, when two types of microcapsules are used, the two types of microcapsules exhibit moisture absorption / desorption performance in accordance with the moisture absorption performance. For example, by combining a first microcapsule that absorbs and releases moisture at a high humidity of about 60% RH and a second microcapsule that absorbs and releases moisture at a low humidity of about 40% RH, for example, In high temperature and high humidity conditions, the first microcapsule absorbs a large amount of humidity because of high humidity. On the other hand, in low temperature drying such as in winter, the second microcapsule is low in humidity and low in saturated water vapor. Can supply humidity.

The humidity control material of the present invention as described above comprises:
Since the surface of the deliquescent inorganic salt 1 is microencapsulated by forming the outer shell layer 2 having a large number of micropores 3, the deliquescent inorganic salt 1 may be sticky even after absorbing moisture. Also, since the microcapsules do not fuse with each other, they can be mixed with other materials, such as adhesives or paints, at an arbitrary ratio and fixed to the surface of various materials, or if they are air-permeable materials. It can also be mixed inside. For example, it can be fixed to the surface of glass, metal material, plastic material, paper, or the like, or can be mixed into wood, fibrous material, foamed plastic, or the like. In addition, when blended in a paint or the like, it can be blended in either an oil-based paint or a water-based paint. In the case of an oil-based paint, a solvent that does not dissolve the plastic constituting the outer shell layer 2 is selected as a solvent for the paint. There is a need. In the case of a water-based paint, the deliquescent inorganic salts may absorb moisture, so it is necessary to apply the paint immediately after mixing, and it is preferable that the paint is sufficiently dried after the application.

Specific applications include fixing to the surface of interior materials and the like, mixing into the interior of heat insulating materials such as wallpaper and foam, and mixing into fibers of interior decoration items such as curtains and carpets. By fixing it inside a circulator or an air conditioner, humidity can be absorbed at high humidity, while moisture can be released at low humidity to provide a comfortable living space. In this case, as described above, it is effective to use two or more types of microcapsules having different moisture absorption / release properties. If only the purpose of dehumidification is intended, use microcapsules with low moisture absorption (dehumidification) starting moisture in which deliquescent inorganic salts have been dried in advance and a large amount of moisture absorption, and use window capsules or closets in interior materials. In particular, it can be provided only in a location where moisture tends to take place, and only the dehumidifying effect can be required. Conversely, microcapsules that sufficiently wet the deliquescent inorganic salts in advance and have a low moisture absorption (dehumidification) start humidity and a large amount of moisture release are provided on the food display case and the inner panel material of the food transport vehicle and the like. Thereby, it can be used mainly for exerting a moisture release function and preventing drying of foods and the like.

The humidity adjusting material of the present invention can be used as it is. For example, a microcapsule in which deliquescent inorganic salts have been dried in advance can be used as a desiccant by filling in a permeable small bag made of woven fabric, nonwoven fabric, paper, or the like, or filled in a permeable plastic container to remove moisture. Can be used as

Further, a layer filled with the microcapsules is provided inside an air conditioner, a dehumidifier / humidifier, an air purifier, or the like, and air is circulated through the layer to perform dehumidification / dehumidification. It may be. In this case, dehumidification and dehumidification can be performed more efficiently by forcibly circulating air by a fan or the like to form a fluidized bed of the microcapsules.

[0024]

The present invention will be described in more detail with reference to the following specific examples. Example 1 3.8 g of polystyrene was added to 26.3 ml of dichloromethane.
(35 g) to prepare a polystyrene solution. Sorbitan 0.04 as a dispersant was added to this polystyrene solution.
After adding 0 g, an aqueous solution of calcium chloride (concentration 42.
7%) 10.0 ml was charged, and 120 rpm by a stirrer.
The mixture was stirred at m for 3 minutes to prepare a dispersion in which droplets of an aqueous solution of calcium chloride were dispersed. Subsequently, this dispersion was poured into water in which 0.5% by weight of polyvinyl alcohol was dissolved, and
pm for 1 hour and 30 minutes to remove dichloromethane in the polystyrene coating to form micropores and an average particle size of 100
μm microcapsules were produced.

Example 2 To a polystyrene solution prepared in the same manner as in Example 1 was added an appropriate amount of sorbitan as a dispersing agent, and then 3.0 ml of an aqueous calcium chloride solution (concentration: 42.7%) was added, followed by stirring at 120 rpm with a stirrer. After stirring for minutes, a dispersion in which droplets of an aqueous solution of calcium chloride were dispersed was prepared. Subsequently, this dispersion was poured into water in which 0.5% by weight of polyvinyl alcohol was dissolved, and the mixture was stirred at 120 rpm for 1 hour and 30 minutes to remove dichloromethane in the polystyrene coating to form micropores, and the average particle size was 100 μm. Microcapsule (sample 2)
Was manufactured.

The test sample 1 and the sample 2 for confirming the function of absorbing and releasing moisture are put into an incubator, respectively.
After standing for 95 minutes, silica gel was charged into the incubator. After leaving for 195 minutes, remove the silica gel, put in a petri dish containing water, measure the mass of each of Sample 1 and Sample 2 every 30 minutes during a total of 330 minutes, and dehumidify from the difference between the front and rear masses. The amount was calculated. Here, the amount of moisture release is (weight of the sample measured immediately before) − (weight of the sample measured). When this value is plus, the amount of moisture release is used. Are respectively shown. The results are shown in Table 1 together with the standing conditions and the humidity. The standing temperature was 27 to 29 ° C., and the initial weight of Sample 1 was
1.2640 g, the initial weight of sample 2 is 1.2502 g
Met.

[0027]

[Table 1]

As is clear from Table 1, Samples 1 and 2, which are the moisture-absorbing materials of the present invention, quickly release moisture at a humidity of 45%, and gradually release the moisture even when the humidity in the incubator is reduced by the addition of silica gel. You can see it getting wet. Then, it is understood that when water is added and the humidity in the incubator becomes excessive, moisture starts to be absorbed. This test confirmed that moisture release / absorption was repeated according to the humidity.

Moisture Release Test (Low Humidity ) Samples 1 and 2 were sufficiently absorbed in water, then placed in an incubator with an initial humidity of 42%, and left for 330 minutes to reduce the mass of each of Samples 1 and 2 to 30. The measurement was performed every minute, and the difference in mass before and after the measurement was measured. The results are shown in Table 2 together with the humidity. The leaving temperature is 28-29 ° C.
The initial weight of sample 1 was 4.7716 g, and the initial weight of sample 2 was 2.8091 g.

[0030]

[Table 2]

As apparent from Table 2, Sample 1 and Sample 2
It was confirmed that, when the water was sufficiently contained, moisture was rapidly released for a long time at a humidity of 42%.

Moisture Release Test (High Humidity) Samples 1 and 2 were sufficiently absorbed in water, then placed in an incubator with an initial humidity of 61%, and the masses of Samples 1 and 2 during 420 minutes were respectively measured. The measurement was performed every 30 minutes, and the difference in mass before and after the measurement was measured. The results are shown in Table 3 together with the humidity. The leaving temperature is 26-29 ° C.
The initial weight of sample 1 was 3.0716 g, and the initial weight of sample 2 was 1.3353 g.

[0033]

[Table 3]

As apparent from Table 3, Sample 1 and Sample 2
It was confirmed that, in a state in which water was sufficiently contained, moisture quickly and for a long time was released even at a high humidity of 61%.

Moisture Absorption Test (Low Humidity ) Samples 1 and 2 were heated to 60 ° C. to dry and precipitate calcium chloride in the microcapsules, and then placed in an incubator with an initial humidity of 41% and left for 300 minutes. Of each of Samples 1 and 2 was measured every 30 minutes, and the difference between the masses before and after that was measured. The results are shown in Table 4 together with the humidity. The leaving temperature is 27-29 ° C.
The initial weight of sample 1 was 0.5457 g, and the initial weight of sample 2 was 0.5216 g.

[0036]

[Table 4]

As apparent from Table 4, Sample 1 and Sample 2
It has been confirmed that, when dried, it absorbs moisture for a long time even under relatively dry conditions of 41% humidity.

Moisture Release Test (High Humidity) Samples 1 and 2 were heated to 60 ° C. to dry and precipitate calcium chloride in the microcapsules, and then samples 1 and 2 were sufficiently absorbed in water. The sample 1 and the sample 2 were put into an incubator with a humidity of 59% and left for 330 minutes, the mass of each of the samples 1 and 2 was measured every 30 minutes, and the difference between the mass before and after that was measured. Table 5 shows the results together with the humidity.
Shown in The standing temperature was 27 ° C., the initial weight of Sample 1 was 0.8338 g, and the initial weight of Sample 2 was 1.014.
2 g.

[0039]

[Table 5]

As apparent from Table 5, Sample 1 and Sample 2
It has been confirmed that, when dried, it absorbs moisture quickly and for a long time under relatively humid conditions of 59% humidity.

Humidity control function test (moisture absorption) The dried microcapsules of sample 1 were 8 cm × 8 cm.
3 g was sealed in a nonwoven fabric bag of No. 1 to obtain a humidity control material. Nine pieces of this humidity control material were prepared.
It was installed in a box having a size of cm × 91 cm and a volume of 0.2275 m 3. Seal the box and change the humidity inside the box by 30 every 5 minutes.
Measured for minutes. The results are shown in Table 6 together with the temperature in the box.

[0042]

[Table 6]

As is clear from Table 6, it is understood that the humidity in the closed box can be rapidly reduced by the moisture absorbing effect of the humidity adjusting material of the present invention.

Humidity control function test ( moisture release) The microcapsules of sample 1 sufficiently filled with water
3 g was sealed in a nonwoven fabric bag of mx 8 cm to obtain a humidity control material. Nine pieces of this humidity control material are prepared, and the inner diameter 50c with the humidity of 47%.
It was installed in a box measuring mx 50 cm x 91 cm and having a volume of 0.2275 m3. The box was sealed and the humidity change in the box was measured every 5 minutes for 30 minutes. Table 7 shows the results together with the temperature in the box.
Shown in

[0045]

[Table 7]

As is clear from Table 7, the humidity in the closed box can be rapidly increased by the moisture releasing action of the humidity adjusting material of the present invention.

[0047]

According to the first aspect of the present invention, since the humidity adjusting material comprises microcapsules containing deliquescent inorganic salts, the deliquescent salts store moisture when the humidity is high, and when the humidity decreases, the dehydrating salts store the moisture. The humidity control function can be exhibited by releasing the moisture.

Further, in the humidity control material according to the second aspect, since the microcapsules have fine pores in the first aspect, the diameter and the number of the fine pores are varied to absorb and release moisture. Adjustment of the wet function is possible.

The humidity control material according to claim 3 is the method according to claim 1 or 2, wherein
Two or more kinds of capsule walls having different thicknesses and different pore diameters are used. For this reason, by making the thickness of the capsule wall and the diameter of the micropores different, it is possible to adjust the moisture absorption / release function.

Further, the humidity adjusting material according to claim 4 is the one according to any one of claims 1 to 3, wherein the deliquescent inorganic salts are contained in a microcapsule as a solution. It's easy.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a microcapsule constituting a humidity control material of the present invention.

[Explanation of symbols]

 1 deliquescent inorganic salts (or their solution) 2 outer shell layer 3 micropores

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D052 AA08 CA00 FA01 GA01 GB02 GB03 GB13 GB14 GB17 HA11 HA12 HA13 HA49 HB01 HB02 HB05 4G065 AA07 AB05X AB07X AB13X AB32Y AB38X BA07 BA13 BB01 BB06 CA02 DA10 EA01 EA03

Claims (4)

[Claims] 1. A humidity control material comprising microcapsules containing deliquescent inorganic salts. 2. The humidity control material according to claim 1, wherein said microcapsules have micropores. 3. The humidity adjusting material according to claim 1, wherein two or more kinds of microcapsules having different capsule wall thicknesses and different pore sizes are used. 4. The humidity control material according to claim 1, wherein the deliquescent inorganic salts are contained in a microcapsule as a solution.