JPH1176815A - Humidity regulating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display a humidity regulation function by which moisture is stored in a moisture-absorbing polymer when it is heavily damp and the accumulated moisture is released when humidity is at a low level. SOLUTION: This humidity regulating material comprises a first and a second microcapsule 11, 12 with a different moisture absorbing performance from each other and a coating when it is applied to the surface of an interior trim material 14. The first and the second microcapsules 11, 12 have an outer shell layers 2, 2A of a polystyrene resin with numerous fine pores formed on the surface of particles 1, 1A of soda polyacrylate.

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 moisture in a water-absorbing polymer when the humidity is high and releases the stored water when the humidity decreases, thereby exhibiting a humidity control function.

[0002]

[0005] In a wooden building such as a general home as well as a concrete building such as a building or a condominium, a difference in humidity easily occurs between seasons and between daytime and nighttime. For example, when 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 an appropriate humidity range.

[0003] For this reason, the current situation is that humidity is conventionally adjusted using a humidifier or a dehumidifier, but it is difficult to provide both functions of humidification and dehumidification. Was also somewhat limited. In addition, a large amount of energy such as electricity must be consumed in order to always maintain a suitable humidity using a humidifier or a dehumidifier. In addition, moisture in the atmosphere is absorbed as moisture by using a moisture absorbing material such as a natural cellulosic material. These materials can absorb moisture, but it is necessary to release the absorbed moisture. Was not suitable.

[0004] Incidentally, not only in the living environment but also in storage cases and display cases for foods and the like, it may be necessary to avoid excessive drying and excessive moisture. It is difficult to manage.

[0005] Therefore, while using a water-absorbing polymer such as sodium polyacrylate to reduce the humidity by absorbing moisture in the water-absorbing polymer at high humidity, the moisture is released from the water-absorbing polymer during drying to increase the humidity. Although it is conceivable to adjust the humidity by doing this, the water-absorbing polymer represented by sodium polyacrylate has a swelling property, so when absorbing humidity, the particles of the water-absorbing polymer fuse and adhere to each other. It is not suitable for use in a state where it is exposed to various cases. In particular, it is desirable that the humidity adjustment function can be exhibited quickly and stably.

The present invention has been made on the basis of the above-mentioned problems, and is a humidity control material that exhibits a humidity control function by storing water in a water-absorbing polymer at high humidity and releasing the stored water when the humidity decreases. The purpose is to provide.

[0007]

Means for Solving the Problems In view of the above object, as a result of intensive studies, the present inventors have formed an outer shell layer having fine pores on the surface of particles of a water-absorbing polymer such as sodium polyacrylate using polystyrene or the like. By microencapsulation, it is not sticky even if it absorbs moisture, it is easy to handle, and it can be mixed with paints and resin binders, so that a water-absorbing polymer layer can be formed on the surface or inside of interior materials and various cases. It has been found that it can be formed. Further, the present inventor, by adjusting the thickness of the outer shell of the microcapsules of the water-absorbing polymer and the ratio of voids due to micropores,
It has been found that the water-absorbing performance of the microcapsules made of this water-absorbing polymer can be made different, and various moisture-regulating functions can be provided by combining them. The present invention has been made based on these.

That is, the humidity control material of the first aspect of the present invention comprises microcapsules containing a water-absorbing polymer.

The humidity control material according to claim 2 uses two or more kinds of microcapsules having different water absorption performance.

[0010] Further, in the humidity control material according to claim 3, the microcapsule has a large number of micropores in an outer shell thereof,
The water absorption performance is varied depending on the difference in the fine pores.

Hereinafter, the humidity control material of the present invention will be described in detail. The water-absorbing polymer used in the present invention has a high water-absorbing property and is used for absorbing water and the like, and does not include those having a slight water-absorbing property such as general polymer compounds. . As such a water absorbing polymer, sodium polyacrylate can be used. The sodium polyacrylate is basically obtained by polymerizing sodium acrylate, but is copolymerized with another monomer that can be polymerized with sodium acrylate within a range that does not impair the water absorbing property. Or a blend of a small amount of other components with sodium polyacrylate, which has different water absorption performance depending on the degree of polymerization (molecular weight), structure, and the like. Here, the water absorption performance means a moisture absorption / desorption amount, a water absorption speed, a water absorption sensitivity, and the like. Examples of commercially available products of sodium polyacrylate as described above include "Aqua Keep" (trade name) and "US40-" manufactured by Sumitomo Chemical Co., Ltd.
G "(product name).

The microcapsules used in the present invention are obtained by forming an outer shell layer 2 having a large number of micropores 3 on the surface of a water-absorbing polymer particle 1 as shown in FIG. 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.
Particularly, polystyrene is preferable.

The microcapsules having the outer shell layer 2 having a large number of micropores 3 formed on the surface can be manufactured by a so-called submerged drying method. This in-liquid drying method is performed as follows. First, a polystyrene solution is prepared by dissolving polystyrene to be the outer shell layer 2 in a volatile solvent such as dichloromethane. The concentration of this polystyrene solution is preferably 5 to 20% by weight, with the total of polystyrene + solvent being 100% by weight. If the amount of polystyrene is less than 5% by weight, the outer shell layer 2 formed becomes too thin, making it difficult to form a complete outer shell layer 2, while 20% by weight.
If the concentration exceeds the above, the concentration becomes too high, and the solution tends to be non-uniform, and the homogeneity of the obtained microcapsules decreases.

Next, sodium polyacrylate is dispersed in the polystyrene solution to form a film of the solution on the surface of the sodium polyacrylate particles. After that, take out this sodium polyacrylate from the polystyrene solution,
This is put into the 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 sodium polyacrylate particles having a coating film formed of a polystyrene solution on the surface are immersed in water, only dichloromethane, which is a solvent, is removed from the coating film. Can be obtained.

As described above, the microcapsules of sodium polyacrylate can have various water absorbing properties by adjusting the manufacturing conditions. For example, if the concentration of the polystyrene solution is low, the outer shell layer 2 is formed thinner and more micropores 3 are formed. Therefore, if microcapsules are produced from two kinds of polystyrene solutions, the lower concentration of the polystyrene solution becomes a microcapsule (first microcapsule) in which the outer shell layer 2 is thinner and the ratio of the micropores 3 is larger, and The higher one is a microcapsule (second microcapsule) in which the outer shell layer 2 is thick and the ratio of the micropores 3 is small. For this reason, the first microcapsules can absorb and release moisture more quickly than the second microcapsules, and have high sensitivity to humidity, so that moisture absorption and desorption are performed at lower humidity. . Therefore, humidity adjustment can be controlled by combining these microcapsules having different water absorption performances.

The size and ratio of the micropores 3 are not limited to the concentration of the polystyrene solution, and the volatilization rate of the solvent dichloromethane is changed by changing the temperature of the water in which the sodium polyacrylate particles are immersed after immersion in the polystyrene solution. It can be changed by adjusting. Further, by making the resin component constituting the outer shell layer 2 different, microcapsules having different water absorbing performance can be obtained.

The particle size of the microcapsules thus obtained basically depends on the sodium polyacrylate particles to be used, but is generally 10 μm to 1 mm.
Preferably it is 100 to 1000 μm. The size of the fine holes 3 depends on the manufacturing conditions, but is 0.01 to 0.0.
It is about 9 μm.

A microcapsule containing a water-absorbing polymer as described above has a sensitivity in the range of 30 to 80% RH, generally 50 to 60% RH, and the humidity is within a predetermined range within this range. If it is higher than this value, the humidity in the atmosphere is absorbed as moisture, and if it is lower than this value, the absorbed moisture is released to adjust the humidity. The water absorption depends on the particle size of the microcapsules, but is usually 2 to 10 times the weight of the microcapsules. Therefore, theoretically, if microcapsules are dispersed at a rate of 1 g per 1 cm ^2, it is possible to absorb about 20 to 100 kg of water per 1 m ² .

The humidity control material of the present invention as described above comprises:
It is preferable to use a mixture of two or more microcapsules having different water absorption properties according to the intended use, environment and the like. For example, when two types of microcapsules are used, the two types of microcapsules exhibit moisture absorption / desorption performance in accordance with the water absorption performance. For example, by combining a microcapsule having a high water absorption rate and a small water absorption amount with a microcapsule having a low water absorption rate and a large water absorption amount, the humidity can be quickly adjusted and the effect can be maintained for a long period of time. .

As described above, the humidity control material of the present invention comprises:
Since the water-absorbing polymer particles 1 are formed of microcapsules having the outer shell layer 2 having a large number of micropores 3 formed on the surface thereof, the water-absorbing polymer does not become sticky even after absorbing water, and the microcapsules can be connected to each other. Since it does not fuse, it can be immobilized on the surface of various materials or mixed in with other materials, such as adhesives and paints, at an arbitrary ratio. Specifically, glass,
It is also applicable to plastic, paper, wood, fibrous materials, and the like. In addition, when blended in paint, etc., oil-based paint,
A water-based paint can be used, but in the case of an oil-based paint, a solvent such as polystyrene that does not dissolve the outer shell layer must be used. In the case of a water-based paint,
It is necessary to apply immediately after mixing so that the water-absorbing polymer does not absorb moisture, and it is preferable to sufficiently dry after application.

[0021]

Next, a method of using the humidity adjusting material of the present invention comprising the above-described microcapsules will be described.

First, as a first embodiment, as shown in FIG. 2, a humidity control material can be used by applying it to the surface of an interior material of a building such as a house. In FIG. 2, the first microcapsule 11 and the second
Microcapsules 12 and resin binder such as oil-based paint
13 is applied to the surface of the interior material 14. The first microcapsules 11 and the second microcapsules 12 are formed by forming outer shell layers 2 and 2A having a large number of micropores made of polystyrene resin on the surfaces of sodium polyacrylate particles 1 and 1A. Due to the difference in the particle size of the sodium acrylate particles 1 and the difference in the size and density of the micropores in the outer shell layer 2 due to the difference in the manufacturing process, the first microcapsule has a high water absorption rate and about 60% RH. The second microcapsule 12 absorbs and desorbs moisture at a low rate of water absorption but a large amount of absorbed water at about 60% RH.

The application of such a humidity adjusting material to the interior material 14 is performed, for example, by using the first and second microcapsules 11 and 12.
Can be mixed in a predetermined ratio (for example, a ratio of 1: 1) to a paint or the like, and spraying, brushing, or the like can be used to carry out the mixing in a conventional manner.

By applying two types of microcapsules 11 and 12 having different water absorption properties to the surface of the interior material 14 as in this embodiment, the following effects can be obtained. Regarding moisture absorption, when the indoor humidity rises during the rainy season or rainfall and exceeds, for example, about 60% RH, the first and second microcapsules 11 and 12 each start to absorb the moisture W1 in the air. At this time, first, the first microcapsules 11 having a high water absorption speed quickly absorb excessive humidity and suppress the rise in indoor humidity. Then, after that, the second microcapsules 12 begin to function, so that dehumidification can be performed until the indoor humidity approaches 60% RH. Contrary to this, the humidity in the room is reduced due to the continued sunny weather and about 60
When the value is much lower than% RH, the moisture W2 is released into the air from the first and second microcapsules 11 and 12 and the moisture is complemented in the room, so that an excessive decrease in humidity can be suppressed. Surface area 1cm ² per 0 of interior material 14 in theory.
It is possible to absorb about 10 to 50 kg of water in 1 m ² only by dispersing the microcapsules 11 and 12 at a ratio of 5 g. Therefore, the layer of microcapsules
It is not necessary to provide it in the entire area of 14, and a sufficient dehumidifying effect can be expected even if it is formed only in a portion which is particularly likely to be moist, such as a window frame or a closet.

As described in detail above, by applying the microcapsules 11 and 12 containing the water-absorbing polymer to the surface of the interior material 14, a change in indoor humidity can be suppressed.
In particular, in this embodiment, since two types of microcapsules 11 and 12 having different water absorption performances are used, first, the first microcapsules 11 quickly suppress the rise in humidity, and then the second microcapsules 11 This effect can be maintained at 12 and, on the contrary, during drying, moisture can be released to suppress overdrying, thereby maintaining good humidity. This humidity adjustment effect can adjust the humidity at which moisture is absorbed and released by changing the type of water-absorbing polymer and the fine pores of the outer shell. By using the humidity adjusting material for the interior material in this way, for example, in the case of a window frame, dew condensation can be prevented. Further, in the case of a bathroom or the like, fungicidal properties can be imparted.

In the first embodiment, the interior material is a metal panel such as an aluminum plate, a hot-dip galvanized plate, a stainless steel plate, or the like, which forms the wall surface, floor surface, or ceiling surface of a building, or vinyl chloride. And various materials used for the interior of buildings, such as synthetic resin panels, glass plates, wallpaper, wood, etc., including those already installed.
Furthermore, it includes bathroom wall materials, tiles, windows and window frames.

Next, as described above, the humidity adjusting material of the present invention is not limited to the surface of an interior material or the like.
It can be used by applying it to the inside of the display case. In FIG. 3, a first microcapsule 21 and a second microcapsule 22 are applied to the bottom surface 24A of the display case 24 with a resin binder 23 such as an oil paint. The first microcapsules 21 and the second microcapsules 22 are formed by forming outer shell layers 2 and 2A having a large number of fine holes made of polystyrene resin on the surfaces of sodium polyacrylate particles 1 and 1A. Due to the difference in the particle size of the sodium acrylate particles 1 and the difference in the size and density of the micropores in the outer shell layer 2 due to the difference in the manufacturing process, the first microcapsule 21 has a low water absorption rate but a small water absorption amount. The second microcapsule 22 has a high water absorption speed and absorbs and desorbs moisture at about 50% RH.

By applying two types of microcapsules 21 and 22 having different water absorption properties to the bottom surface 24A of the display case 24, the following effects can be obtained.
For moisture absorption, the display case 24
When the humidity inside rises and exceeds 40% RH, first, the first microcapsules 21 begin to absorb the moisture W1 in the air in the case. At this time, the first microcapsules 21
Since the amount of water absorption is large, an increase in humidity in the display case 24 can be suppressed. And, temporarily, the display case 24
When the humidity in the inside exceeds 50% RH, the second microcapsules 22 start to function, but since the second microcapsules 22 have a high water absorption speed, the humidity in the display case 24 is quickly reduced to 50%. % RH. Conversely, the humidity inside the display case 24 decreases,
When the humidity is much lower than 0% RH, the moisture W2 is released into the air from the first and second microcapsules 21 and 22 and the moisture is complemented in the display case 24, so that an excessive decrease in humidity is suppressed. Can be. In addition, since the display case 24 has relatively little air flow, 1 cm is placed on the bottom surface 24A of the display case 24.
Microcapsules 21 and 22 in a small amount of 0.1 g per ²
It is possible to absorb about ² to 10 kg of water in 1 m ² only by dispersing the water, which is particularly suitable for controlling the humidity in a small space as in this embodiment.

As described in detail above, the bottom surface 24 of the display case 24
Microcapsules 21 and 22 containing water-absorbing polymer in A
By applying, the humidity in the case 24 can be controlled. In particular, in this embodiment, since two types of microcapsules 21 and 22 having different water absorption performances are used, first, the first microcapsules 21 are used to suppress an increase in humidity,
If the humidity rises beyond the function of the first microcapsule 21, the second microcapsule having a high water absorption rate
The humidity is rapidly lowered at 22 so that the humidity in the display case 24 becomes 50
% RH can be kept so as not to exceed as much as possible, and conversely, moisture can be released during drying to prevent excessive drying. By using the humidity adjusting material for the display case 24 in this manner, for example, antiques and books can be stored in a good state. In addition, it can be used as a food storage case by providing a cooling device and the like.

Although the humidity adjusting material of the present invention has been described above, the present invention is not limited to this.
Various modifications can be made without departing from the spirit of the present invention. For example, the intended use is not limited to interior materials and display cases, but it can be adjusted for indoor humidity by mixing with interior decoration items such as curtains and carpets. In addition, dehumidification and dehumidification can be achieved by including it in the filter of a circulator such as a circulator or
A fungicide function can be provided. In each of the above embodiments, two types of microcapsules were used.
If it is three or more types, finer humidity control is possible. Also, the water-absorbing polymer used is not limited to sodium polyacrylate, and various polymers having high water absorption can be used. it can. Further, the humidity at the boundary between moisture absorption and desorption can be controlled by appropriately controlling the production conditions of the microcapsules in accordance with the intended use. For example, when applied to the interior material 14 or the like as in the first embodiment, It may be set relatively high, set relatively low in the case of a display case as in the second embodiment, and set high in the case of a storage case of fresh food.

[0031]

The present invention will be described in more detail with reference to the following specific examples. Examples 1 to 3 Polystyrene solutions were prepared by dissolving polystyrene in dichloromethane at 7, 10, and 15% by weight (Examples 1, 2, and 3), respectively. Sodium polyacrylate having an average particle size of 500 μm was added to these polystyrene solutions and stirred at 250 rpm for 1.0 hour to form a polystyrene coating on the surface. Subsequently, the sodium polyacrylate was poured into water in which 0.5% by weight of polyvinyl alcohol was dissolved, and the mixture was stirred at 250 rpm for 1.0 hour to remove dichloromethane in the polystyrene coating to form fine pores and obtain an average particle size. Each of 550 μm microcapsules was produced.

These microcapsules were subjected to a humidity of 80% R
FIG. 4 shows the results of measuring the amount of water absorption per 1 g of each sample left for 6 hours in H. FIG. 4 also shows the results of measuring the amount of water absorption per g of sodium polyacrylate alone for reference.

As is clear from FIG. 4, each of the microcapsules of Examples 1 to 3 was about 8 g / g,
It had a water absorption of 5 g and 2 g, and it was confirmed that the water absorption differs depending on the concentration of the polystyrene solution. Examples 4 and 5 "Aquakeep" (manufactured by Sumitomo Chemical Co., Ltd.) as a sodium polyacrylate in a polystyrene solution obtained by dissolving polystyrene in dichloromethane at a ratio of 10% by weight (Example 4)
"US40-G" (Example 5) is charged and 25
The mixture was stirred at 0 rpm for 1.0 hour to form a polystyrene coating on the surface. Subsequently, the sodium polyacrylate was added to water in which 0.5% by weight of polyvinyl alcohol was dissolved,
The mixture was stirred at 250 rpm for 1.0 hour to remove dichloromethane in the polystyrene coating to produce microcapsules having an average particle size of 600 μm.

These microcapsules were treated with a humidity of 80% R
FIG. 5 shows the results of measuring the amount of water absorption per gram by leaving the sample in H for 3 hours. In addition, the figure shows the results of measuring the change in water absorption (moisture release rate) when the water content after absorption was 1 after leaving the microcapsules sufficiently absorbed in water at 30% RH for 2 hours. 6 is shown.

As is apparent from FIGS. 5 and 6, the microcapsules of Example 4 have a water absorption of about 2 g per gram, and the moisture release rate is high but the moisture release rate (1-water content). Is low. On the other hand, the microcapsules of Example 5 have a water absorption of about 3 g per gram, indicating that the rate of moisture release is low but the rate of moisture release is high. From this result, it can be seen that the microcapsules show different water absorption depending on the difference of sodium polyacrylate.

[0036]

The humidity control material according to the first aspect of the present invention is composed of microcapsules containing a water-absorbing polymer, so that water is stored in the water-absorbing polymer when the humidity is high, and when the humidity decreases, the stored water is used. By releasing water, a humidity adjustment function can be exhibited. Further, since it is not sticky even when it absorbs moisture and has good handleability and can be mixed with a paint or a resin binder, it can be applied to various uses.

Further, since the humidity adjusting material according to the second aspect uses two or more kinds of microcapsules having different water absorbing properties, the humidity adjusting ability can be controlled by a combination of the microcapsules. .

Further, in the humidity control material according to claim 3, the microcapsules have a large number of micropores in an outer shell thereof,
Since the water absorption performance is varied due to the difference in the fine pores, fine adjustment of the water absorption / desorption rate and the amount of moisture absorption is possible, and the humidity adjustment ability can be more finely controlled by combining them. .

[Brief description of the drawings]

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

FIG. 2 is a schematic view showing a state in which a humidity adjusting material according to a first embodiment of the present invention is provided on the surface of an interior material.

FIG. 3 is a schematic view showing a state in which a humidity adjusting material according to a second embodiment of the present invention is provided in a display case.

FIG. 4 is a chart showing the results of measuring the water absorption of the microcapsules of Examples 1 to 3.

FIG. 5 is a chart showing the results of measuring the water absorption of the microcapsules of Examples 4 and 5.

FIG. 6 is a chart showing the results of measuring the moisture release rate of the microcapsules of Examples 4 and 5.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water-absorbing polymer particle 2 Outer shell layer 3 Micropore 11,21 First microcapsule (microcapsule) 12,22 Second microcapsule (microcapsule)

Claims (3)

[Claims] 1. A humidity control material comprising microcapsules containing a water-absorbing polymer. 2. The humidity adjusting material according to claim 1, wherein two or more kinds of microcapsules having different water absorption performance are used. 3. The humidity control material according to claim 2, wherein the microcapsules have a large number of micropores in an outer shell thereof, and have different water absorption properties depending on the difference between the micropores. .