阅读说明：本技术 耐释放性硬质吸湿剂组合物及包含其的吸湿制品 (Release-resistant rigid moisture absorbent compositions and absorbent articles comprising the same ) 是由 安广镐 郑荣镇 于 2019-11-15 设计创作，主要内容包括：本发明提供耐释放性硬质吸湿剂组合物及包含其的吸湿制品。本发明的耐释放性硬质吸湿剂组合物的特征在于,包含金属氯化物30～70重量％、金属氧化物20～50重量％、纤维素衍生物1～10重量％和脂质5～20重量％。根据本发明制造的吸湿制品通过将金属氯化物、金属氧化物、纤维素衍生物和脂质的组成比调节至特定范围,从而能够在维持高吸湿率的同时抑制由高温等环境中水分释放导致的腐蚀、生锈、生成物的外部流出,且能够使吸湿导致的体积变化最小化,因而能够有效用作安装在汽车灯内的吸湿制品。(The present invention provides a release-resistant hard moisture absorbent composition and a moisture absorbent article comprising the same. The release-resistant hard moisture absorbent composition is characterized by comprising 30-70 wt% of metal chloride, 20-50 wt% of metal oxide, 1-10 wt% of cellulose derivative and 5-20 wt% of lipid. The moisture absorbent article manufactured according to the present invention can suppress corrosion, rusting, and external outflow of products due to moisture release in an environment of high temperature or the like while maintaining a high moisture absorption rate, and can minimize a volume change due to moisture absorption by adjusting the composition ratio of the metal chloride, the metal oxide, the cellulose derivative, and the lipid to a specific range, and thus can be effectively used as a moisture absorbent article installed in an automobile lamp.)

1. A release-resistant hard moisture absorbent composition is characterized by comprising 30-70 wt% of metal chloride, 20-50 wt% of metal oxide, 1-10 wt% of cellulose derivative and 5-20 wt% of lipid.

2. The release-resistant hard desiccant composition of claim 1 wherein the metal chloride is any one or more selected from the group consisting of calcium chloride, magnesium chloride, lithium chloride, strontium chloride, yttrium chloride, and copper chloride.

3. The composition of claim 1, wherein the metal oxide is one or more selected from the group consisting of calcium oxide, barium oxide, magnesium oxide, strontium oxide, sodium oxide, and potassium oxide.

4. The composition as claimed in claim 1, wherein the cellulose derivative is any one or more selected from nitrocellulose, acetyl cellulose, methyl cellulose, ethyl cellulose, benzyl cellulose, carboxymethyl cellulose and hydroxymethyl cellulose.

5. The release-resistant rigid moisture absorbent composition of claim 1 wherein the lipid is any one or more selected from the group consisting of beeswax, lanolin, candelilla wax, petrolatum, polyethylene wax, polypropylene wax, polyamide wax, carnauba wax, paraffin wax and polytetrafluoroethylene wax.

6. An absorbent article comprising the release-resistant hard moisture absorbent composition according to any one of claims 1 to 5, wherein the absorbent article has a volume change rate of 120% or less as measured at 50 ℃ and 95% relative humidity, and has a moisture release rate and a moisture absorption rate of 0.8% or less and 160% or more as measured at 50 ℃ and 95% relative humidity, respectively.

Technical Field

The present invention relates to a release-resistant hard moisture absorbent composition and a moisture absorbent article including the same, and more particularly, to a release-resistant hard moisture absorbent composition and a moisture absorbent article including the same, which have a high moisture absorption rate and a low release rate and can minimize a volume change due to moisture absorption by adjusting a composition ratio of a metal chloride, a metal oxide, a cellulose derivative, and a lipid to a specific range.

Background

The moisture absorbent is a substance that is contained in a container and absorbs moisture in the container to maintain a good storage state of an object present in the container, and is used for storing moisture-sensitive products such as medicines, foods, semiconductors, and metal instruments.

In general, a moisture absorbent is configured by enclosing and sealing a moisture absorbing component in a packaging material, and the moisture absorbing ability of the moisture absorbent is determined by the moisture absorbing ability of the moisture absorbing component enclosed in the packaging material, and it is also important to manage so as not to allow moisture absorbed in the packaging material to flow out to the outside.

In particular, with the development of the automobile industry, condensation of the headlamps, tail lamps, fog lamps, and the like is continuously generated during transportation and storage of automobiles, and thus, industrial losses are increased.

In the case of an automotive lamp, when the temperature difference between the inside and the outside of the part is large in an environment with a large humidity such as rain, if the lamp lens temperature is low, moisture inside the lamp condenses to form minute water droplets on the inner surface of the lens, and steam frosts. The resulting light scattering phenomenon is a great obstacle in safe driving of automobiles.

In order to solve such problems, the automobile industry has heretofore utilized a method of mounting an antifogging coating agent and a bentonite-based moisture absorbent in a lamp cover such as a dust cover. However, the antifogging coating agent suffers from cracking such as whitening or clouding due to outdoor ultraviolet rays, temperature, humidity, and the like, and in this case, there is a problem of replacement of the automobile lamp set. Further, in general, the bentonite-based moisture absorbent has the following problems: after absorbing a certain amount of moisture, moisture is released again in a high-temperature and low-humidity environment when the lamp is turned on, resulting in a condensation phenomenon on the inner surface of the lamp lens.

On the other hand, in the case of a conventional moisture absorbent composed of only calcium chloride or magnesium chloride, although the moisture absorbent is strong in moisture absorption, there is a possibility that the moisture absorbing liquid in a liquid state flows after moisture absorption, causing a fatal problem to an object existing inside the container.

In order to compensate for such a defect, when the material is mixed with calcium oxide or magnesium oxide as a concrete raw material, the material is solidified to form concrete when absorbing moisture, but in this case, there is a possibility that volume expansion and excessive moisture absorption remain in a liquid phase (deliquescence) and finally such a liquid phase substance flows out.

Further, if the moisture absorbent contained in the container expands in volume as the moisture absorbent increases, the inner wall of the container may exert pressure on the moisture absorbent due to restriction of the inner space of the container, whereby the moisture absorbent absorbing the liquid phase inside the moisture absorbent may flow out to the outside of the packaging material. Therefore, in order to improve such a problem, a property of minimizing the expansion rate due to moisture absorption like a sponge is required, and a moisture absorbent having a new function of maintaining such a property is required.

Documents of the prior art

Patent document

Korean laid-open patent No. 10-2015-0058825 (2015, 05, 29 days)

Disclosure of Invention

Problems to be solved

The present invention has been made to solve the above-mentioned problems, and more particularly, to a release-resistant hard moisture absorbent composition and a moisture absorbent article including the same, which can suppress external outflow due to moisture release while maintaining a high moisture absorption rate by adjusting the composition ratio of a metal chloride, a metal oxide, a cellulose derivative, and a lipid to a specific range, and can minimize a volume change due to moisture absorption.

Means for solving the problems

The present invention relates to a release-resistant hard moisture absorbent composition and a moisture absorbent article comprising the same.

The present invention relates to a release-resistant hard moisture absorbent composition, which is characterized by comprising 30-70 wt% of metal chloride, 20-50 wt% of metal oxide, 1-10 wt% of cellulose derivative and 5-20 wt% of lipid.

In the present invention, the metal chloride is characterized by being one or more selected from the group consisting of calcium chloride, magnesium chloride, lithium chloride, strontium chloride, yttrium chloride and copper chloride,

the metal oxide is characterized by being one or more selected from the group consisting of calcium oxide, barium oxide, magnesium oxide, strontium oxide, sodium oxide and potassium oxide,

the cellulose derivative is characterized by being any one or more selected from the group consisting of nitrocellulose, acetyl cellulose, methyl cellulose, ethyl cellulose, benzyl cellulose, carboxymethyl cellulose and hydroxymethyl cellulose.

The lipid is characterized by being one or more selected from beeswax, lanolin, candelilla wax, vaseline, polyethylene wax, polypropylene wax, polyamide wax, carnauba wax, paraffin wax, and polytetrafluoroethylene wax.

An aspect of the present invention relates to an absorbent article comprising the above-mentioned release-resistant hard moisture absorbent composition, wherein the absorbent article has a volume change rate of 120% or less as measured at 50 ℃ and 95% relative humidity, and has a moisture release rate and a moisture absorption rate of 0.8% or less and 160% or more as measured at 50 ℃ and 95% relative humidity, respectively.

Effects of the invention

The moisture absorbent article manufactured according to the present invention can suppress corrosion, rusting, and external outflow of products due to moisture release in an environment of high temperature or the like while maintaining a high moisture absorption rate, and can minimize a volume change due to moisture absorption by adjusting the composition ratio of the metal chloride, the metal oxide, the cellulose derivative, and the lipid to a specific range, and thus can be effectively used as a moisture absorbent article installed in an automobile lamp.

Detailed Description

Hereinafter, the release-resistant hard moisture absorbent composition of the present invention and the moisture absorbent article comprising the same will be described in more detail with reference to examples and comparative examples. However, the specific examples described below are provided as examples to fully convey the concept of the present invention to those skilled in the art.

Therefore, the present invention is not limited to the specific examples provided below, and may be embodied in other forms.

In this case, the technical terms and scientific terms used have meanings that are commonly understood by those skilled in the art to which the present invention belongs if not defined otherwise, and descriptions of well-known functions and configurations that may unnecessarily obscure the gist of the present invention are omitted in the following description.

Furthermore, as used in the specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

The release-resistant hard moisture absorbent composition of the present invention is characterized by containing a metal chloride, a metal oxide, a cellulose derivative, and a lipid.

In the present invention, the metal chloride absorbs moisture in the atmosphere on the basis of high deliquescence and can improve rust prevention in some cases, and the chloride of an alkali metal or an alkaline earth metal is mainly used.

Examples of the metal chloride include calcium chloride, magnesium chloride, lithium chloride, strontium chloride, yttrium chloride, and copper chloride, and these may be used alone or in combination of two or more.

In the present invention, the metal chloride may preferably contain magnesium chloride. The above magnesium chloride (MgCl)₂) The moisture absorption rate is as high as 1.5 times or more higher than that of other metal chlorides, and the most excellent moisture absorption is obtained, and besides the anhydrous substance, there are 2, 4, 6, 8, 10, 12 hydrates and the like, and the 6 hydrate (MgCl) is usually used as the hydrate₂·6H₂O) exists in the form of a crystal.

The magnesium chloride is a main component of brine, which is a by-product of salt extraction from seawater, and is relatively easily available and has excellent deliquescence, and therefore, is most preferable for the moisture absorbent composition of the present invention.

In the present invention, the method for producing the metal chloride is not limited. However, in order to make the metal chloride deliquescent, it is necessary to use the metal chloride in a dry state, and therefore, the production process must include a drying step. In this case, the conditions for details of the drying step are not limited in the present invention, and it is preferable to perform drying in an oven set at a temperature of 150 ℃ or higher, or to perform vacuum drying, freeze drying, or the like.

In the present invention, the production process of the metal chloride is not limited. For example, in the case of aluminum chloride, it can be obtained by leaching kaolin several times with hydrochloric acid and then filtering various impurities as described in "manufacture of magnesium oxide (+ 99% MgO) by Ruthner-HCl-manufacture" (Andritz-Ruthner Industriangen Aktiengesellschaft, Aichholzgasse 51-53, A-1120 Vienna, pages 5-7) by Hans Jedlika and the like.

Further, the metal chloride may be further mixed with a silicon compound. The silicon compound can immobilize corrosion products such as metal ions and chloride ions generated in the process of moisture absorption of the metal chloride, and thus can greatly improve the rust-proof effect.

In the present invention, the kind of the silicon compound is not limited, and zeolite is preferably used. The zeolite is a crystalline aluminosilicate mineral and has a property of strongly adsorbing polar substances by the action of cations present in the crystal structure, and therefore not only the corrosion product but also water are adsorbed, and since it has fine pores of a certain size, molecules smaller than the fine pores can be selectively passed and adsorbed.

In the present invention, the silicon compound may be prepared as a mixed moisture-adsorbing component of a metal chloride-silicon compound by dissolving a metal chloride in water to prepare a solution, mixing porous zeolite with the solution, spraying the solution to form a droplet form having a predetermined average particle diameter, and drying the droplet form.

In the present invention, the content of the silicon compound is preferably 100 to 500 parts by weight based on 100 parts by weight of the metal chloride. Within the above range, a stable moisture adsorption capacity can be exhibited, and rust inhibitive performance can be greatly improved.

In the present invention, the content of the metal chloride is preferably 30 to 70% by weight, more preferably 45 to 55% by weight, based on 100% by weight of the entire composition. When the content is less than 30% by weight, the moisture adsorption performance is greatly reduced, and when the content is more than 70% by weight, the deliquescence is excessively increased, and thus the corrosion product in a liquid phase may be released.

In the present invention, the metal oxide itself can adsorb moisture due to its high deliquescence, and the initial liquefaction of magnesium chloride can be prevented by the reaction described later.

The metal oxide includes, for example, any one or more selected from the group consisting of calcium oxide, barium oxide, magnesium oxide, strontium oxide, sodium oxide, and potassium oxide, and these may be used alone or in a mixture of two or more.

In the present invention, the metal oxide may more preferably contain magnesium oxide. The magnesium oxide forms a needle-like hydrated product, and absorbs the initially liquefied metal chloride, thereby maintaining the solid form. The magnesium oxide reacts with the metal chloride, more specifically, magnesium chloride, to cause a curing reaction.

To describe this in more detail, metal chlorides, particularly magnesium chloride, have a property of absorbing moisture even with a slight amount of moisture due to high deliquescence, and therefore can be provided with a high moisture absorption function. However, the magnesium chloride is liquefied while absorbing moisture due to a deliquescence phenomenon, and an aqueous solution generated by the liquefaction phenomenon acts as a corrosion product, thereby greatly reducing rust prevention. However, if magnesium oxide is mixed, the aqueous solution of magnesium chloride and magnesium oxide form magnesium oxide cement and undergo hydration reaction to form a solid, thereby suppressing deliquescence of the initial metal chloride and preventing liquefaction. To form such magnesia cements, the composition will absorb more water, after which the deliquescence phenomenon of the metal chloride will cease. Therefore, by such a mechanism, unlike conventional metal chlorides and silica gels, the side effect of releasing the absorbed moisture again can be suppressed, and the rust prevention property can also be improved.

In the present invention, the content of the metal oxide is preferably 20 to 50% by weight, and more preferably 30 to 40% by weight, based on 100% by weight of the entire composition. In the case of the content of less than 20 wt%, it is difficult to control the high deliquescence of the metal chloride and the rust inhibitive effect may be greatly reduced, and in the case of more than 50 wt%, the hygroscopicity may be reduced due to a caking phenomenon (caking effect) caused by a severe reaction of magnesium oxide.

In the present invention, the metal chloride or the metal oxide is preferably added in the form of powder. In this case, the specific surface area of the metal chloride or metal oxide is not particularly limited, but preferably the specific surface area BNT is not less than 10 square meters per gram, more preferably not less than 40 square meters per gram.

In the present invention, the cellulose derivative is used for compensating for defects of the metal oxide or the metal chloride, and a solidified body formed by the metal oxide or the metal chloride absorbing moisture is a hydrated product having a needle shape, which causes a problem that the packaging material is opened or damaged due to expansion of the content. Therefore, in order to suppress such drawbacks of the hydrated product, it is possible to prevent the breakage of the packaging material due to the solidification of the metal oxide and the metal chloride while ensuring the moisture absorbing ability of the cellulose derivative itself by simultaneously adding a high molecular weight cellulose derivative.

In addition, since the cellulose derivative itself has both electrostatic repulsion and hydrophilicity, it can have a certain level of dehumidification property at the same time regardless of a change in relative humidity.

In the present invention, as the cellulose derivative, nitrocellulose, acetyl cellulose, methyl cellulose, ethyl cellulose, benzyl cellulose, carboxymethyl cellulose, hydroxymethyl cellulose and the like can be exemplified, and among them, carboxymethyl cellulose is preferably used because it contains both-COONa having electrostatic repulsive force and-OH having hydrophilicity, and can accommodate a larger amount of water molecules while swelling between internal structures.

The method for producing the cellulose derivative is not limited. For example, a modified cellulose derivative can be generally produced by esterifying or etherifying a part of hydroxyl groups (-OH) in cellulose. Representative etherified cellulose derivatives include Carboxymethyl cellulose (CMC), Hydroxyethyl cellulose (HEC), Hydroxypropyl cellulose (HPC), and esterified cellulose derivatives include Nitro cellulose (Nitro-cellulose), cellulose acetate (cellulose acetate).

The cellulose derivative is not limited in form and the like, as with the metal chloride or the metal oxide. For example, the cellulose derivative may be in the form of particles, and the size thereof may have an average diameter of 0.1 to 20 μm.

The cellulose derivative is preferably contained in an amount of 1 to 10 wt%, more preferably 3 to 7 wt%, based on 100 wt% of the total composition. When the content is less than 1% by weight, the magnesia cement production rate of the composition during the initial moisture absorption process is rapidly increased and the packaging material or the like may be damaged, and when the content is more than 10% by weight, the excessive volume increase of the composition during the moisture absorption process may cause the breakage of the packaging material.

In the present invention, when the temperature around the composition changes, the composition may release absorbed water as it changes from a solid to a liquid, and the lipid serves to prevent such a phenomenon. In addition, the lipid also has the effect of reducing the viscosity of the composition to improve the processability of the lubricant.

In the present invention, the kind of the lipid is not limited, and may be any one or more selected from beeswax, lanolin, candelilla wax, vaseline, polyethylene wax, polypropylene wax, polyamide wax, carnauba wax, paraffin wax, polytetrafluoroethylene wax, and the like. Among them, polyethylene wax is preferably used for the effect of moisture release resistance and uniform dispersion of the composition.

In the present invention, the content of the lipid is preferably 5 to 20% by weight, more preferably 5 to 15% by weight, based on 100% by weight of the total composition. When the content is less than 5% by weight, it is difficult to prevent the liquid phase of the composition due to temperature change, and when the content is more than 20% by weight, the other components and the lipid may be phase-separated after the composition is cured to generate corrosion products.

In addition to this, the release-resistant hard moisture absorbent composition of the present invention may further comprise various additives. Specifically, the above additives may further contain known types of catalysts, surface active additives, emulsifiers, reaction retarders, pigments, dyes, flame retardants, age resistors, scorch retarders, plasticizers, antibacterial agents, fillers, and the like.

The amount of the additive is not limited, and can be freely adjusted for each component. For example, the additive may be added in an amount of 0.01 to 10 parts by weight per 100 parts by weight of the entire composition.

The present invention can provide an absorbent article comprising the above-mentioned release-resistant hard moisture absorbent composition. Specifically, the absorbent article may have a form in which a packaging material having a housing space therein is sealed inside the packaging material.

In the present invention, the packaging material may be a breathable film composed of one or more layers. For example, the above-mentioned packaging material may be a two-layer film structure in which a coating layer containing a synthetic latex is formed on a breathable film. In this case, the air-permeable packaging material is preferable because it has an advantage of good heat resistance. In this case, the double-layer film structure may be formed by a process of applying a coating solution containing 30 to 40 wt% of synthetic latex, 2 to 10 wt% of Ethylene-vinyl acetate (EVA) substance, 50 to 60 wt% of solvent, and 1 to 5 wt% of other substances to the air-permeable film according to a known method, and after applying the coating solution, if necessary, a drying process using a known method may be performed.

The synthetic latex used for forming the above coating layer is preferably an acrylic latex binder and/or an acrylic latex resin, and more specifically, is not particularly limited as long as an appropriate specification known in the art is selected. The EVA material used to form the coating is preferably a hot melt adhesive comprising EVA, again with appropriate specifications known in the art. Other substances that are components of the coating liquid for forming the coating layer are a curing agent, an inorganic filler and/or an additive resin, the curing agent may be at least one selected from the group consisting of an amine-based curing agent, an acid anhydride-based curing agent, a phenol-based curing agent and a dicyandiamide-based curing agent, the inorganic filler may be at least one selected from the group consisting of calcium carbonate, magnesium carbonate, talc, mica, kaolin, graphite and silica, and the additive resin may be at least one selected from the group consisting of a terpene phenol resin, a hydrogenated rosin, a petroleum resin, a xylene resin and a coumarone resin. As the solvent of the component of the coating liquid for forming the coating layer, at least one selected from the group consisting of toluene, acetone, and methyl ethyl ketone can be exemplified.

The thickness of the coating layer is not limited in the present invention, and is preferably 1 μm to 50 μm, and more preferably 5 μm to 10 μm.

As for the breathable film of the packaging film of the breathable packaging material included in the absorbent article of the present invention, the breathable film may include at least one selected from the group consisting of Tyvek (Tyvek), PP (polypropylene) nonwoven fabric, PE (polyethylene) nonwoven fabric, PET (polyethylene terephthalate) nonwoven fabric, paper, and cloth. From the viewpoint of imparting good heat resistance to the packaging material, it is preferable to use a breathable film made of Tyvek. Accordingly, the packaging film of the breathable packaging material included in the absorbent article of the present invention may preferably be a two-layer film structure in which a coating layer is formed on a breathable film made of Tyvek.

As described above, the moisture-absorbing article manufactured according to the present invention has a volume change rate of 120% or less measured at 50 ℃ and 95% relative humidity, and a moisture release rate and a moisture absorption rate of 0.8% or less and 160% or more measured at 50 ℃ and 95% relative humidity, respectively, by adjusting the composition ratio of the metal chloride, the metal oxide, the cellulose derivative and the lipid to a specific range.

The present invention will be described in more detail below with reference to examples and comparative examples. However, the following examples and comparative examples are merely illustrative examples for illustrating the present invention in more detail, and the present invention is not limited by the following examples and comparative examples.

The physical properties of the test pieces produced in the following examples and comparative examples were measured as follows.

(sample)

The product specifications of the samples used in the examples and comparative examples are shown in table 1 below.

[ Table 1]

Distinguishing	Composition comprising a metal oxide and a metal oxide	Manufacturing company	Name of product	Remarks for note
					A	Magnesium chloride	Aldrich (Aldrich)	-	The purity is 94%
B	Magnesium oxide	Daming chemistry	-	CAS.NO：1309-48-4
					C	Carboxymethyl cellulose	SHINWON business society	-	CAS.NO：9004-32-4
D	Polyethylene wax	SFC	LH1200	Softening point: 109. + -. 3 ℃ C

(moisture absorption Rate)

After the test piece was exposed to a temperature of 50. + -. 2 ℃ and a relative humidity of 95. + -. 5% for 7 days using a thermostat and a humidity meter, the weight was measured every 24 hours, and the measured weight was substituted into the following formula 1 to calculate the moisture absorption rate.

[ formula 1]

(Release Rate resistance)

After the test pieces were allowed to absorb moisture at a temperature of 23. + -. 2 ℃ and a relative humidity of 50. + -. 5% for 48 hours, they were dried again in an oven set at 70. + -. 2 ℃ for 2 hours, and the moisture absorption rates at the drying temperatures were measured for each. That is, after initial moisture absorption, drying is performed, and moisture absorption rates of the initial and the dried moisture absorption rates are measured, respectively, and the release resistance is calculated by substituting each moisture absorption rate into the following formula 2. For example, the release resistance of 90% means that 90% of the moisture originally absorbed remains after drying.

[ formula 2]

(rate of volume change)

The dimensional change rate (DC) due to moisture absorption was measured under the same conditions as the measurement of the absorptanceSize (L) of test piece of the same sample_wet) And measuring the size (L) of the initial test piece_dry) Then, the following formula 3 is substituted.

[ formula 3]

Further, after the test piece was inserted into the covering type protective container, it was exposed to a temperature of 50. + -. 2 ℃ and a relative humidity of 95. + -. 5% for 7 days using a thermostat and then confirmed with the naked eye.

Examples 1 to 7 and comparative examples 1 to 7

The moisture absorbents were produced by uniformly mixing the components in the composition ratios described in table 2 below. Next, 35g of the moisture absorbents of examples 1 to 7 and comparative examples 1 to 7 were put into a breathable packaging material having a length and a width of 100mm, respectively, and then processed at a temperature of 120 ℃ by a heat sealing machine to produce test pieces. In this case, a commercially available product (Desikhan, HM) was used as a test piece of comparative example 1. The physical properties of the test pieces thus produced were measured and are shown in tables 3 to 4 below.

[ Table 2]

[ Table 3]

As can be seen from table 3, the moisture absorbent produced according to the present invention can effectively absorb moisture in the atmosphere based on high deliquescence. Specifically, examples 1 and 3 in which the content of the metal chloride was maintained within an appropriate range were found to maintain the moisture absorption rate of 160% or more, although there was some difference. However, in example 2 in which the metal oxide was slightly added in excess, it was found that the moisture absorption rate was relatively lowered. Presumably, this is because the magnesium oxide reaction causes the caking phenomenon to occur rapidly.

Further, it was confirmed that the moisture absorbent produced in example 1 had no large difference in volume change even after the moisture absorption rate test when compared with a commercially available moisture absorbent (comparative example 1). Specifically, it was confirmed that the moisture absorbent of example 1 hardly undergoes a volume change even after absorbing moisture, but the volume of the moisture absorbent of comparative example 1 is greatly increased to deform the casing.

[ Table 4]

As shown in table 4, the moisture absorbent produced according to the present invention also shows an excellent value in the emission resistance. In particular, it was confirmed that the addition amounts of the metal chloride, the metal oxide, the cellulose derivative and the lipid satisfy the most excellent release resistance shown in example 1 of the present invention, whereas the release resistance greatly decreased in comparative examples 2 to 7 in which the addition amount of the composition was deviated from the standard.