JP2010194497A - Desiccant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a desiccant that is excellent in hygroscopic performance, can sufficiently prevent a deliquescent inorganic salt from being liquefied, and scarcely affects the environment. <P>SOLUTION: There are provided (1) a desiccant including deliquescent inorganic salt and nonionic cellulose derivative, (2) the desiccant including 10-50 pts.wt. of the nonionic cellulose derivative and 100 pts.wt. of the deliquescent inorganic salt, (3) the desiccant given in (1) or (2), wherein the viscosity of an aqueous solution of 2 mass% of the nonionic cellulose derivative is 10,000 to 100,000 mPa s at 20°C, and (4) the desiccant given in (1) to (3), wherein the deliquescent inorganic salt is calcium chloride and the nonionic cellulose derivative is hydroxyethylmethyl cellulose. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a desiccant for preventing the generation of rust, mold and condensation due to moisture during storage / packaging transportation of precision equipment, machine parts, electronic parts, clothes, glass products and the like.

Conventionally, deliquescent inorganic salts such as calcium chloride and magnesium chloride have been used as desiccants for household and industrial use. However, the deliquescent inorganic salt is liable to be liquefied after moisture absorption, causing problems in handling such as leakage from the desiccant container and soiling the surroundings. Therefore, in order to prevent liquefaction of the deliquescent inorganic salt and prevent its leakage, a method of using it together with a gelling agent has been proposed. For example, Patent Document 1 discloses a dehumidifying agent obtained by mechanically mixing a powder or granule of a deliquescent inorganic compound and a powder or granule of a hydrophilic polymer such as carboxymethyl cellulose. Patent Document 2 discloses a desiccant mainly composed of a mixture of a deliquescent salt and an acrylamide polymer.

However, carboxymethyl cellulose has a slow gelation rate and may not be able to retain water at the beginning of moisture absorption, and there is a possibility that the material to be dried may be damaged due to water leakage from the packaging material. In addition, acrylamide produced by the decomposition of polyacrylamide by heat or light is known as a carcinogenic substance, and there is concern about adverse environmental effects. Therefore, even these gelling agents are insufficient or inappropriate for preventing liquefaction of the deliquescent inorganic salt.

JP 60-28531 A JP-A-3-30814

Therefore, an object of the present invention is to provide a desiccant that has excellent moisture absorption performance, can sufficiently prevent liquefaction of a deliquescent inorganic salt, and has little adverse effect on the environment.

As a result of diligent research to solve the above problems, the inventor of the present invention has a desiccant containing a specific gelling agent that has excellent hygroscopic performance, can sufficiently prevent liquefaction of deliquescent inorganic salts, and has an environmental impact. As a result, the present invention was completed.
That is, the desiccant according to the present invention is as follows.
(1) A desiccant containing a deliquescent inorganic salt and a nonionic cellulose derivative.
(2) A desiccant containing 10 to 50 parts by weight of a nonionic cellulose derivative with respect to 100 parts by weight of a deliquescent inorganic salt.
(3) The desiccant according to (1) or (2) above, wherein the viscosity of a 2% by mass aqueous solution of the nonionic cellulose derivative is 10,000 to 100,000 mPa · s at 20 ° C.
(4) The desiccant according to (1) to (3), wherein the deliquescent inorganic salt is calcium chloride and the nonionic cellulose derivative is hydroxyethylmethylcellulose.

ADVANTAGE OF THE INVENTION According to this invention, the desiccant which is excellent in moisture absorption performance, can fully prevent liquefaction of a deliquescent inorganic salt, and has little influence on an environment can be provided.

FIG. 1 is a graph showing the change over time in the moisture absorption rate of the desiccant.

The present invention is described in detail below.
Examples of the deliquescent inorganic salt used in the present invention include calcium chloride, zinc chloride, tin chloride, magnesium chloride, and phosphorus pentoxide. In particular, calcium chloride is preferable because it is inexpensive, harmless, and has high moisture absorption performance. The deliquescent inorganic salt can be used in any form of fine powder, fine granules, and granules, and is not particularly limited.

The gelling agent used in the present invention is a nonionic cellulose derivative. Nonionic cellulose derivatives include hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, etc. Especially, hydroxyethylmethylcellulose has little adverse effect on the environment, and even from the desiccant at the initial stage of moisture absorption. It is preferable because water leakage hardly occurs.

Among the hydroxyethyl methylcelluloses, the viscosity of a 2% by weight aqueous solution is preferably 10,000 to 100,000 mPa · s at 20 ° C., more preferably 35,000 to 100,000 mPa · s, and more preferably 35,000 to 70,000 mPa · s. Further preferred.
Hydroxyethyl methylcellulose having a viscosity of 2 mass% aqueous solution of less than 10,000 mPa · s at 20 ° C. has a small water absorption capacity, and it is necessary to increase the mixing ratio of hydroxyethyl methylcellulose. In addition, it is currently difficult to obtain hydroxyethyl methylcellulose having a viscosity exceeding 100,000 mPa · s.

The desiccant of the present invention preferably contains 10 to 50 parts by weight of a nonionic cellulose derivative with respect to 100 parts by weight of the deliquescent inorganic salt. If the nonionic cellulose derivative is less than 10 parts by weight, it is not sufficient to prevent liquefaction, and if the nonionic cellulose derivative exceeds 50 parts by weight, the content of the deliquescent inorganic salt in the desiccant is relatively small. As a result, the amount of moisture absorption decreases.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
[Materials used]
1. 1. Calcium chloride: industrial product made in China 2. Hydroxyethyl methylcellulose (HEMC): manufactured by Samsung, Korea Hydroxypropyl methylcellulose (HPMC): manufactured by Samsung, Korea Carboxymethylcellulose (CMC): Nippon Paper Chemicals

[Penetration resistance test]
Each material was mixed in a thermostatic chamber at 30 ° C. according to the formulation shown in Table 1, and then a mixed solution obtained by mixing 300 parts by weight of distilled water with 100 parts by weight of calcium chloride was put into a mold and left for 24 hours. Left to stand. Next, the penetration resistance value from the surface of the generated gel to a depth of 1 cm perpendicularly was measured with a digital force gauge manufactured by Imada Corporation. Moreover, the flat exclusive attachment was used for the grounding surface of the gel. Table 1 shows the measurement results of the penetration resistance value.

注）表中の貫入抵抗値以外の数値は塩化カルシウム１００重量部に対する各材料の重量部を示す。

Note) Numerical values other than penetration resistance values in the table indicate parts by weight of each material relative to 100 parts by weight of calcium chloride.

As can be seen from Table 1, the gel of the desiccant containing hydroxyethylmethylcellulose and hydroxypropylcellulose, which are nonionic cellulose derivatives, has a high penetration resistance value of 0.3 to 3.5 N / cm ² , and the gel surface has There was no leakage of water. On the other hand, water leaked to the surface of the desiccant gel using carboxymethyl cellulose, which is an ionic cellulose derivative, and the penetration resistance value could not be measured.

[Hygroscopicity test and time course of desiccant]
A desiccant (A) in which 43 parts by weight of hydroxyethyl methyl cellulose was mixed with 100 parts by weight of calcium chloride and a desiccant (B) in which 25 parts by weight were mixed were each enclosed in a bag made of moisture-permeable waterproof paper. Next, the bag is left in a constant temperature and humidity chamber at 30 ° C. and 90% RH, and the moisture content is determined by periodically measuring the weight of the desiccant, and the bag is dried by the feel of the bag. The presence or absence of liquefaction of the agent was investigated.
In addition, with respect to 100 parts by weight of calcium chloride, a desiccant (C) in which 42 parts by weight of carboxymethyl cellulose was mixed and a desiccant (D) in which 25 parts by weight were mixed were sealed in bags made of moisture-permeable waterproof paper, respectively. The test was conducted in the same manner as described above.
The moisture absorption is shown in FIG. 1 and the tactile feel of the bag is shown in Table 2.

注）◎：粉体の状態 ○：流動性のないゲルの状態 ×：一部が液状化した状態

Note) ◎: Powder state ○: Non-flowable gel state ×: Partially liquefied state

As can be seen from FIG. 1 and Table 2, the desiccants (A) and (B) containing hydroxyethyl methylcellulose are superior in moisture absorption performance to the desiccants (C) and (D) containing the same amount of carboxymethyl cellulose, And liquefaction can be prevented.

Claims (4)

  A desiccant comprising a deliquescent inorganic salt and a nonionic cellulose derivative.   A desiccant comprising 10 to 50 parts by weight of a nonionic cellulose derivative with respect to 100 parts by weight of a deliquescent inorganic salt.   The desiccant according to claim 1 or 2, wherein a viscosity of a 2 mass% aqueous solution of the nonionic cellulose derivative is 10,000 to 100,000 mPa · s at 20 ° C.   The desiccant according to any one of claims 1 to 3, wherein the deliquescent inorganic salt is calcium chloride, and the nonionic cellulose derivative is hydroxyethylmethylcellulose.

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