KR940006399B1 - Desiccant - Google Patents

Abstract

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Description

Humidity Composition and Humidity Molded Product

1 is a curve diagram showing the humidity control function of the sheet sample obtained in Example 1 of the present invention and the comparative plate sample.

2 is a curve showing the humidity control function of the sheet sample obtained in Example 2 of the present invention.

3 is a curve diagram showing the humidity control function of another sheet sample obtained in Example 2 of the present invention.

4 is an explanatory diagram showing the layer structure of the three-layer inflation film obtained in the embodiment of the present invention.

5 is an explanatory diagram showing the layer structure of an A1 coat laminate film obtained in Example 3 of the present invention.

6 is an explanatory diagram showing the layer structure of the KOP coat laminate film obtained in Example 3 of the present invention.

FIG. 7 is a curve diagram comparing the humidity control function between the bag of the present invention made of the film shown in FIG. 4 and the bag of a comparative commercial item. FIG.

FIG. 8 is a curve diagram comparing the humidity function between the bag of the present invention made from the film shown in FIG. 5 and the bag of a comparative commercial item. FIG.

9 is a curve diagram showing the humidity control function between the bag of the present invention made from the film shown in FIG. 6 and the bag of a comparative commercial item.

10 is a curve diagram showing the humidity control function between the sample and the comparative general product in the inner lid of the photosphere container obtained in Example 4 of the present invention.

FIG. 11 is a curve diagram comparing the humidity function between the sheet sample obtained in Example 5 of the present invention and a comparative sheet sample made using commercially available magnesium sulfate. FIG.

12 is a micrograph showing the crystal structure of the surface after moisture absorption with respect to the sample obtained in Example 5 of the present invention.

Fig. 13 is a micrograph showing the crystal structure of the surface after moisture absorption with respect to the comparative sheet sample shown in Example 5 of the present invention.

14 is a curve diagram showing the results of a hygroscopic test on the foamed bilayer product sample obtained in Example 6 of the present invention.

FIG. 15 is a graph showing the moisture absorption rate of an anhydrous magnesium sulfate-containing polyethylene sheet sample obtained in Example 7 of the present invention and a comparative magnesium sulfate pentahydrate-containing polyethylene sheet.

The present invention relates to a humidity control composition having a humidity control function capable of maintaining humidity at a constant humidity, and a humidity molded article obtained in the composition.

Conventionally, silica gel, calcium chloride, quicklime, zeolite, and the like are used for the purpose of preventing quality deterioration of products such as oxidation due to moisture absorption in all fields such as food, medicine, electronic parts and precision machinery. Drying tax was used. These desiccants were used in the form of granules or granules, packed with paper or nonwoven fabric, or put into a wrapping material together with the product in a state enclosed in a container or the like.

Desiccants such as silica gel, zeolite, calcium chloride, and quicklime, which are conventionally used as desiccants, have strong drying and hygroscopicity, depending on their physical and chemical properties. When placed in sealed containers and bags, they absorb moisture within a short time and absorb Continue to absorb moisture inside until it reaches 0%. This is a chemical and physical action of each desiccant, and when used in a cloth or the like used to seal a product to the outside, it is not possible to keep the humidity constant and maintain the humidity at an appropriate level. That is, the conventional desiccant did not have a humidity control function.

The present invention has a humidity control function that was not possible with a conventional desiccant, and has a humidity control function having a humidity control function that can be maintained at an arbitrary constant humidity in the range of 60 to 10% of humidity, and a humidity control molded article obtained from the composition. It is aimed at.

MEANS TO SOLVE THE PROBLEM This invention was completed as a result of careful research by the present inventors in order to achieve the said objective, and it has moisture control property by mix | blending specific amount of a specific moisturizer with a thermoplastic resin, Furthermore, moisture absorption power, It has succeeded in providing an excellent humidity control composition in terms of scattering property, persistence, and detoxification.

That is, the humidity control composition of the present invention is MgSO ₄ · nH ₂ O (where 0 ≦ n ≦ 3) with respect to 100 parts by weight of thermoplastic resin, and 5 to 400 magnesium sulfate having an average particle diameter of 30 μm or less. It is made by mixing by weight.

Magnesium sulfate defined in this way, when moisture is absorbed, initially produces hexate, and only the hexate increases with the increase of the moisture absorption. It is a humectant that changes to 7-beard when it is minimized, that is, when the heat of absorption reaches 43 to 48%.

Although the thermoplastic resin used for this invention is not specifically limited, A well-known thing can be used, For example, polyethylene (PE), polypropylene (PP), a polycarbonate, a polyamide (PA), an ethylene- vinyl acetate copolymer ( EVA), ethylene-methylacrylate copolymer (EMA), ethylene-methacrylate copolymer, polyvinyl chloride, polystyrene, polyester, polyvinylidene chloride (PVDC), and the like, and one or two or more of them. You can use

In addition, in the present invention, as the humectant used with the thermoplastic resin, excellent dispersibility in respect to magnesium sulfate represented by the formula MgSO ₄ · nH ₂ O (where 0 ≦ n ≦ 3), in particular, the former resin Magnesium sulfate having Magnesium sulfate hydrate that exceeds trihydrate releases hydrated water when it is mixed with the resin by heating when mixed with the resin, resulting in obstacles during manufacturing and effective humidity control A composition can not be obtained, and even if it is going to make molded articles, such as a film, a sheet, and a container, from this composition, a humidified molded article with a commodity value cannot be obtained. In addition, the said humectant has an average particle diameter of 30 micrometers or less. Magnesium sulfate having a small average particle diameter in this manner has a maximum variation range of specific surface area of 4.0 to 1.5 m ² / g, which is small in variation. And magnesium sulfate may mix and use what differs in particle diameter as needed.

Here, when the average particle diameter of magnesium sulfate exceeds 30 micrometers, the moisture absorption rate of a hygroscopic composition slows down. In addition, the variation of the specific surface area of magnesium sulfate is large, and when a molded article is made from a humidity control composition, expansion, shrinkage, cracking, etc. of the molded article occur due to moisture absorption, so that the length stability cannot be maintained and a practical molded article cannot be obtained. do.

The ratio of the raw material mix | blended in this invention is 5-400 weight part of humectants with respect to 100 weight part of thermoplastic resins, and it selects suitably according to a use within this range. In the case where the ratio of the humectant is in the above range, the humectant has good dispersibility in the resin, has a high humectability, hygroscopicity, water retention, and persistence, and is excellent in moldability. A composition can be obtained.

In the humidity control composition of this invention, a foaming agent can also be added as a raw material other than the said thermoplastic resin and a humectant. The blowing agent is not particularly limited, and known ones can be widely used, and examples thereof include azoisobutyronitrile, azodicarbonamide, 4,4'-oxybenzenesulfonylhydrazide, and the like. As for the usage-amount of a foaming agent, 0.2-10 weight part is preferable with respect to 100 weight part of thermoplastic resins. The foamed humidity control molded article obtained from the foamable humidity control composition to which the foaming agent is added is made to have a higher moisture absorption power because it has a light weight and has a moisture absorption effect to the inside of the foam.

In addition, as an additive, a known plasticizer, stabilizer, lubricant, colorant, or the like may be appropriately added to the extent not impairing the object of the present invention as necessary.

Moreover, this invention also includes the humidity-controlled molded article obtained by forming the moisture-humidity composition of this invention.

There is no restriction | limiting in particular as a manufacturing method of the humidity control composition of this invention, and its molded article, Usually, it can manufacture by the following method. That is, when the thermoplastic resin, the humectant, and other additives are mixed at a temperature of about 100 to 350 ° C. at a temperature of about 100 to 350 ° C. by using a mixer such as a mixing grill, a mixing molding machine, etc., if necessary, a humidity control composition is obtained. Moisture-reduced molded articles can be obtained by molding the composition again.

In addition, the moisture-formed molded article of the present invention also includes a layered-humidity-formed molded article obtained by laminating at least one kind of the moisture-permeable laminate obtained from the moisture-permeable composition. As another laminated material laminated | stacked with this moisture-permeable laminated material, resins, such as an electric thermoplastic resin which are raw materials of the composition of this invention, papers, a fiber, metals, various paints, various adhesives, etc. can be used. And at least 1 type of the moisture-humidity laminated material obtained by the humidity control composition of this invention means that two or more types of laminated materials obtained from the humidity control composition of this invention which differed in composition can be used. The kind, quantity (thickness), and number of laminated materials of the laminated material are not limited as long as the object of the present invention is achieved, and can be widely used, and are appropriately selected according to the use (requirement).

The most common example of the lamination is a film, sheet or plate laminated with the moisture-permeable laminate. Although the specific example about the resin structure in the case of this laminated structure is listed next, this invention is not limited to this.

Low Density Polyethylene (LDPE) / Medium Density Polyethylene (MDPE)

High Density Polyethylene (HDPE) / LDPE / HDPE

HDPE / LDPE / LDPE

HDPE / EMA / LDPE

HDPE / Ionoma

PA / ionoma

PP / EVA / PP

PP / EVA / LDPE

PA / Adhesive PE / Ionoma

PA / Adhesive PE / EVA

PA / Adhesive PE / HDPE

PA / Adhesive PE / Straight Low Density Polyethylene (LLDPE)

PA / Adhesive LLDPE / LLDPE

PA / Adhesive PP / EVA

LDPE / PA / EVA

EVA / PVDC / EVA

EVA / PVDC / Ionoma

LDPE / Adhesive PE / PA

In the lamination example, "adhesiveness" means lamination with an adhesive. Moreover, although a moisturizing agent may be contained in any of the said resin layers, since the main purpose of lamination | stacking is in manufacture of a hygroscopic packaging material, it is not necessary to contain it in an outer layer. In addition, aluminum foil or the like may be attached to completely block moisture and light from the outside. Lamination can be easily performed by an extrusion lamination method, a coextrusion lamination method, a multilayer injection linear method, an adhesion method, etc., and the resulting laminate is again a bag or container type. It can be processed easily. As described above, the laminate moisture-permeable molded article of the present invention, in which a waterproof material is laminated on the outer layer and a water-permeable protective material on the inner layer, as necessary, has a humidity control effect and a hygroscopic effect, its life, durability, light shielding properties, and antistatic properties. Improved safety, stability, quality deterioration prevention effect, and more functional to cope with all usage environment.

The humidity control composition of the present invention may be formed into a film, a sheet, by a method such as extrusion molding, coextrusion molding, injection molding, hollow molding, extrusion coating molding, crosslinking foam molding, or the like. It is processed into a shape of a plate shape, a bag shape, a pallet shape, a container shape, a laminated body shape, or the like to form a moisture-absorbing molded article. And the term container here means not only the container itself, but also the lid of the container and the mating of the container with the lid.

When the magnesium sulfate used in the present invention starts moisture absorption under constant temperature conditions, the vapor pressure increases as the hydration step proceeds, and accordingly, the difference with the partial pressure of water vapor in the environment becomes small, and thus the moisture absorption rate As a result, the composition is reduced, and as a result, a composition having a constant humidity and having a humidity control function can also be obtained.

When the magnesium sulfate used in the present invention absorbs moisture, initially hexate is produced, and only the hexate increases with the increase of moisture absorption, and during that time, 1-5 salts do not form, and anhydrous magnesium sulfate is produced. When it reaches the minimum, that is, when the absorption rate is 43 to 48%, it changes to 7 beards. By this fact, unlike a desiccant using other hydrate-forming salts, anhydrides are present even at high moisture absorption, and the moisture absorption power is kept constant, resulting in a composition having a humidity control function.

And magnesium sulfate used by this invention shows the constant vapor pressure which it has, and it can absorb moisture to the place where the partial pressure of the external water vapor and the vapor pressure of self become equilibrium. When the magnesium sulfate is added to the resin, the composite of the resin and the magnesium sulfate exhibits a constant vapor pressure. Unlike the magnesium sulfate monomer, the vapor pressure at this time is influenced by the moisture permeability of the resin to be added and is changed to a different value by the resin. In this case, the equilibrium viscosity is also different, and the equilibrium humidity at which moisture cannot be absorbed is also changed. Therefore, the constant humidity to be maintained can be appropriately adjusted by resin.

Example 1

100 parts by weight of an ethylene-methyl acrylate copolymer (EMA, density 0.94 g / cm ³ ), 100 parts by weight of anhydrous magnesium sulfate (average particle diameter 4.59 μm, specific surface area of 4.0 to 1.5 m ² / g) After kneading with a PCM 45 twin screw extruder manufactured by Iga Kai Iron Co., Ltd., hot cutting was made into pellets, and a sheet having a thickness of 0.5 mm was made by a T-die method. For comparison, 100 parts by weight of low density polyethylene (density 0.921 g / cm ³ ) and 50 parts by weight of zeolite (average particle diameter 8 μm) were equally mixed, and a plate having a thickness of 2 mm was made by an injection molding machine. Similarly, for comparison, low density polyethylene and silica gel (particle size of 200 to 300 mesh) were mixed as in the case of zeolite to make a plate having a thickness of 2 mm by an injection molding machine.

Using these sheets and plates as samples, they were placed in a separate glass container (capacity 0.9L) and the relationship between the moisture absorption rate and the time in the glass container at room temperature was measured, and the results are shown in FIG.

As is clear from the results of FIG. 1, when the sample using zeolite and silica gel is used, the humidity in the glass container becomes 0%, the humidity cannot be kept constant, and it can be seen that there is no humidity control function. In contrast, in the case of the sample of the present invention using anhydrous magnesium sulfate, it was found that the humidity could be stored at 19%, and it had a humidity control function.

Example 2

100 parts by weight of polyamide and 50 parts by weight of anhydrous magnesium sulfate (average particle diameter 4.59 μm, specific surface area of 4.0 to 1.5 m ² / g) were kneaded with the kneading extrusion molding machine used in Example 1, and then hot cutting was made to form pellets. Then, a sheet having a thickness of 0.5 mm was made by the T-die method. In the same manner, a 0.5 mm thick sheet was made from polypropylene and anhydrous magnesium sulfate. The former and the latter sheet samples were put in separate glass containers (capacity 0.9L) to examine the humidity, recovery and sustainability of the former and latter samples in the glass container for a predetermined time (48 hours) at 25 ° C. The recovery limit of moisture absorption in the closed space in the glass container was measured continuously and shown in FIGS. 2 and 3 for the former and latter samples, respectively.

As is apparent from FIG. 2 and FIG. 3, it can be seen that all samples of the present invention have humidity, recovery, and sustainability. Moreover, it is clear that arbitrary humidity can be controlled in this invention by changing the kind of thermoplastic resin.

Example 3

(A) 100 parts by weight of low density polyethylene (density 0.921 g / cm ³ ) and 50 parts by weight of anhydrous magnesium sulfate used in Example 1 were kneaded with the kneading extruder used in Example 1, and then hot cut was made into pellets. In addition, a three-layer film containing 33% anhydrous magnesium sulfate and containing a low density polyethylene film was prepared by the inflation method. As shown in Fig. 4, the contents of the three layers are the high-density polyethylene layer 1 having a thickness of 50 μm in the outer layer, the low-density polyethylene layer 2 having a thickness of 33% magnesium sulfate in the middle layer, and the low-density polyethylene layer 3 having a thickness of 10 μm in the inner layer. As a three-layer inflation film 4 having a thickness of 110 μm, a bag (300 × 200 × 0.11 mm) was again made from this film 4.

(B) The magnesium sulfate containing ethylene-methylacrylate copolymer layer 5 having a thickness of 50 µm obtained by containing 33% of the anhydrous magnesium sulfate in Example 1 in the ethylene-methylacrylate copolymer was used as the intermediate layer. In the same manner as in the case of (A), a three-layer inflation film was formed, and an A1 consisting of a polyethylene terephthalate (PET) layer (thickness 12 μm) 6 / A1 layer (thickness 9 μm) 7 / LDPE layer (thickness 15 μm) 8 on the outer layer. The coat film layer was laminated to make an A1 coat laminate film 9 (FIG. 5) having a thickness of 146 µm, and a bag (300 x 200 x 0.146 mm) was further made from this film 9.

(C) A three-layer inflation film was made in the same manner as in (A), except that the HDPE layer 1 of the outer layer and the LDPE layer 2 of the magnesium sulfate-containing LDPE layer 2 of the intermediate layer were 20 μm and 30 μm, respectively. A Seop KOP # 20 film layer (20 μm thick) 1 manufactured by Daicel Chemical Co., Ltd., coated with polyvinylidene chloride on the film, was laminated to make a KOP coat laminate film 11 (Fig. 6) having a thickness of 80 μm. Made a bag (300 × 200 × 0.08m).

The moisture absorption repetition test in the bag of said (A), (B) and (C) was set to 25 degreeC, and the result about each humidity control function is shown to FIG. 7, FIG. 8, and FIG. For comparison, a commercially available commodity for comparison, i.e., a commercially available polysack having a thickness of 0.06 mm for the bag of (A), a commercially available aluminum coat bag for the bag of (B) and 0.06 mm of a commercial bag for the bag of (C) The same test was carried out for the poly sacks of thickness, and the results are also shown in FIGS. 7, 8, and 9, respectively.

As apparent from the results shown in FIGS. 7, 8, and 9, in the hygroscopic repeat test, in any of the above cases (A), (B), and (C), the present invention maintains a constant temperature. Although it was preserved and the humidity control function was shown, the comparative commercial item did not show the humidity control function.

As described above, it is understood that the humidity control function can be controlled by changing the equilibrium humidity by changing the resin to be overcome. As in the case of (A), (B), and (C) above, the humidity control function can be controlled somewhat by changing the amount of the layer into which the magnesium sulfate is added or the outer layer.

The magnesium sulfate was put in the low-density polyethylene as in the above (A), because the moisture permeability of the resin was lower than that in the ethylene-methylacrylate copolymer as in the above (B). The thing is equilibrium humidity higher than that of (B). The resin of (B) has high moisture permeability called ethylene-methyl acrylate copolymer, and the equilibrium humidity is lower than that of (A) as described above, but as in (C), It is put in the same resin, and it becomes somewhat different equilibrium humidity by the change of layer structure.

Thus, by changing the combination of magnesium sulfate and resin, it is possible to obtain a humidity control film having various humidity control functions having different equilibrium humidity.

Example 4

100 parts by weight of the low-density polyethylene of Example 3 and 50 parts by weight of anhydrous magnesium sulfate of Example 1 were kneaded with the kneading extrusion molding machine of Example 1, followed by hot cutting to form pellets, and the ethylene-methyl acrylate of Example 1 Pellets were prepared in the same manner with 100 parts by weight of the copolymer and 100 parts by weight of anhydrous magnesium sulfate of Example 1. Using two types of pellets, two kinds of samples of inner lids (diameter 9.1mm, thickness 1mm) of 500ml photosphere container were made by using an injection molding machine (PS-20E2VES manufactured by Nissei Resin Co., Ltd.). In order to investigate each humidity control function, a moisture absorption repetition test was conducted in a sealed space in a photosphere container at 25 ° C., and the results are shown in FIG. 10. For comparison, the same test was conducted for the general product for comparison, and the results are also shown in FIG.

As is apparent from FIG. 10, the sample of the present invention has a moisturizing power, but it can be seen that the general sample for comparison has no moisturizing power.

Example 5

100 parts by weight of low density polyethylene (trade name: Sumigaseng F411-1, density 0.92 g / cm ³ ) manufactured by Sumidomo Chemical Co., Ltd. and commercially available magnesium sulfate (average particle diameter: 60 μm, specific surface area: 0.3 to 3.3 m ²⁾ / g) 50 parts by weight was kneaded with the kneading extrusion molding machine used in Example 1, and hot cutting was performed to make pellets, and again, a sheet having a thickness of 0.5 mm (50 mm x 50 mm x 0.5 mm) was made by a T-die method. In particular, except that the anhydrous magnesium sulfate (average particle diameter 4 μm, specific surface area 3.1 to 1.6 m ² / g) used in the present invention was made, a sheet having a thickness of 0.5 mm was made as described above, and the temperature was 25 ° C, A hygroscopic test was carried out under 75% relative humidity. The results are shown in FIG.

As is apparent from the results in FIG. 11, in the case of a sheet made of commercially available magnesium sulfate having an average particle diameter of more than 30 µm, the magnesium sulfate used in the present invention having a smaller average particle diameter of 30 µm or less was used. The moisture absorption rate is slower than the sheet made. After moisture absorption, micrographs (magnification 100 times) were taken on the surface of each sheet, and the photograph of the latter invention sheet was shown as FIG. 12 and the photograph of the former commercially available sheet was shown as FIG.

In the case of the sheet of the present invention of FIG. 12, the surface is not changed as compared with before moisture absorption. On the other hand, commercial magnesium sulfate having a large particle diameter has a large variation in specific surface area, and in the case of the comparative sheet of FIG. 13 using the same, magnesium sulfate is eluted and crystallized after moisture absorption. Shrinkage and cracking occurred and dimensional stability could not be maintained and it did not become a practical molded article.

The anhydrous magnesium sulfate used in the present invention has a small average particle diameter of 4 μm, and fine pores are formed in the particles, thereby providing good humidity control function without causing expansion, shrinkage, elution, cracking, etc. due to stability of the molded article and moisture absorption. Eggplants can make films, sheets, and molded articles.

Example 6

Ethylene-vinylacetate copolymer, an upper layer resin material in which the same weight of polyethylene and calcium carbonate and the required amount of azoisobutyronitrile (foaming agent) are mixed, and the ethylene-vinylacetate copolymer, polyethylene and anhydrous used in Example 1 Independent bubble consisting of two layers of blue (upper layer) and white (lower layer) (both thicknesses are the same) by a mixed foam molding machine using a lower layer resin material in which the same weight of magnesium sulfate and the required amount of the above blowing agent are mixed. A sample of a foamed double-layer product [50 mm x 50 mm x 20 mm (thickness)] of the structure was obtained. About this sample, the moisture absorption rate was measured under the conditions of 25 degreeC of temperature, 75% of relative humidity, 25 degreeC of temperature, and 50% of relative humidity, respectively, and the result was shown in FIG.

As is apparent from FIG. 14, the foamed bilayer product had a high hygroscopic power. In addition, the foamed two-layered product has a humidity control function that requires a long time for moisture absorption when low humidity and a short time when moisture absorption is high.

Example 7

100 parts by weight of the low-density polyethylene of Example 5 and 50 parts by weight of anhydrous magnesium sulfate of Example 1 were kneaded with the kneading extrusion molding machine used in Example 1, and the hot cut was made into pellets, and the thickness was again 0.5% by T-die method. mm (50 mm x 50 mm x 0.5 mm) sheets were made. For comparison, pellets were made in the same manner as above from 50 parts by weight of 100 parts by weight of magnesium sulfate pentahydrate (MgSo ₄ · 5h ₂ o) of the low density polyethylene, and a sheet having a thickness of 0.5 mm was prepared by the T-die method. made. Using these sheets as a sample, the moisture absorption test was carried out under the conditions of a temperature of 25 ° C. and a relative humidity of 75%, and the results of comparing and measuring the respective moisture absorption rates are shown in FIG. 15.

From the results of FIG. 15, it is clear that the sheet sample containing the comparative magnesium sulfate pentahydrate is slow in the moisture absorption rate compared with the sheet sample containing the anhydrous magnesium sulfate used in the present invention.

Like magnesium sulfate, the anhydride of the salt becomes a hydrate and is absorbed to have a constant vapor pressure depending on the hydration state of the salt. This vapor pressure tends to rise as the hydration step proceeds. Naturally, the vapor pressure of anhydrous magnesium sulfate becomes a value lower than the vapor pressure of pentahydrate. When both of these are placed under an environment of 75% relative humidity and 25 ° C, they quickly start to absorb moisture, but the moisture absorption rate is determined by the difference between the partial pressure of water vapor in this environment and the vapor pressure of the respective ones. If the difference is large, the moisture absorption speed is high, and if it is small, it is slow. As a result, the hygroscopic condition is as shown in FIG. 15, and as described above, in the case of the sheet sample containing magnesium sulfate pentahydrate, the moisture absorption rate is lower than in the case of the sheet containing anhydrous magnesium sulfate.

In the case of the anhydrous magnesium sulfate used in the present invention, when the moisture absorption starts at constant temperature conditions, as the hydration step proceeds, the moisture absorption rate decreases as the vapor pressure increases, and a moisture absorption curve as shown in FIG. 15 is drawn. In addition, it can be seen that it has a humidity control function to preserve a constant humidity.

When the magnesium sulfate pentahydrate for comparison is kneaded together with a resin in a kneading extrusion molding machine, when heated in the kneading extrusion molding machine, it releases its own hydrated water, which causes obstacles during manufacture, and can exhibit an effective function. It was not possible to obtain a humidity control composition, and even when trying to make a molded article such as a film, a sheet, or a container from this composition, a product having a commodity value could not be obtained.

The humidity control composition and the humidity molded article of the present invention have the following effects.

1) It maintains constant humidity inside sealed containers and bags, and keeps contents at moderate humidity, that is, humidity control function, and keeps it at a certain constant humidity in the range of 60% to 10% humidity. .

2) It has stable humidity and water retention ability, and also has excellent stability and safety in use as a humectant in order not to cause liquefaction leakage or water droplets caused by corrosion, scattering, hygroscopic liquid phenomena. This effectively prevents deterioration of quality due to oxidation of goods.

3) It does not need to be packaged like a conventional desiccant at the time of use, and is formed as a bag in the shape of a bag, a container, or the like because the cloth itself acts as a moisturizer and exhibits the same moisturizing effect as described above. Acts as.

4) Hygroscopic effect lasts for a long time.

5) It is easy to manufacture and process, and has excellent industrial productivity.

6) It has light blocking property and antistatic property.

7) The foamed moisture-absorbing molded article obtained as a foam has a high moisture absorption since it is light in weight and has a moisture absorption effect to the inside of the foam.

The humidity control composition and the molded article of the present invention to achieve the above effect is a breakthrough that can be used as an excellent humidity control for quality protection in a wide range of fields such as food, medicine, cosmetics, preferences, precision machinery, mechanical parts.

Claims (6)

A humidity control composition formed by blending 5 to 400 parts by weight of magnesium sulfate represented by the formula MgSO ₄ · nH ₂ O (where 0 ≦ n ≦ 3) with an average particle diameter of 30 μm or less with respect to 100 parts by weight of the thermoplastic resin. The method according to claim 1, wherein when magnesium sulfate absorbs moisture, hexate is initially produced, and only hexate is increased as the amount of moisture absorption increases. And the moisture-absorbing composition which is changed into a seven-membered beard when the water absorption becomes 43 to 48%. The foamable humidity control composition according to claim 1 or 2, which contains a blowing agent. The foamable moisture-permeable molded article obtained from the foamable humidity control composition of Claim 3. The moisture-formed molded article of the film form, sheet form, bag form, pellet form, or container which comprises the humidity control composition of Claim 1 or 2. The laminated humidity-moistened molded article which laminated | stacked at least 1 sort (s) of the moisture-permeable laminated material which comprises the moisture-permeable composition of Claim 1 or 2.