JP2012245489A - Hygroscopic composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hygroscopic composition which uses sodium acetate and/or potassium acetate as non-halogen inorganic salt, is inexpensive, exhibits high moisture absorption characteristics and also high safety with less concern of generation of rust or the like of metal.SOLUTION: The hygroscopic composition includes at least one of the sodium acetate and potassium acetate, and a water-absorbing binder. A ratio (Ac: B) between a total amount of the sodium acetate and the potassium acetate (Ac), and an amount of the water-absorbing binder (B) is in a range of 2:3 to 4:1 by mass standard.

Description

  The present invention relates to a hygroscopic composition.

  Conventionally, an inorganic salt-based desiccant is widely known as a drying material used for storage and packaging. In particular, halogen-based inorganic salts such as calcium chloride are widely used as materials exhibiting hygroscopicity because of their excellent hygroscopic ability.

  Halogenous salts such as calcium chloride and magnesium chloride are deliquescent inorganic salts. Although deliquescent inorganic salts absorb a large amount of moisture per unit weight, these inorganic salts liquefy when they absorb moisture (deliquesce). There is a problem that the liquid is separated, causing fluidization and liquid leakage. In particular, when the deliquescent liquid is exuded and separated, there is a concern that halogen salts such as chloride come into contact with the material to be dried and cause corrosion such as rust on the metal material. For this reason, in the scene where products using metals such as processed metal products are stored, packed, etc., it is actually the case that expensive water-absorbing polymer-based desiccants and silica-based desiccants are used.

  As such a desiccant, a desiccant using salts such as calcium chloride and magnesium chloride and sepiolite is disclosed (for example, see Patent Documents 1 and 2). Although deliquescent inorganic salts such as calcium chloride are deliquescent at the time of moisture absorption, the moisture absorption moisture can be retained by mixing with a water retention agent such as sepiolite.

  In addition, desiccants that use halogen-based inorganic salts may generate halogen-based harmful substances due to combustion when discarded, and improvements are expected from the viewpoint of impact on the human body and the environmental impact that has been observed in recent years. The

  On the other hand, silica-based desiccants such as silica gel tend to be significantly inferior in drying ability in terms of hygroscopicity compared to halogen-based inorganic salts such as calcium chloride.

  In view of the above situation, there has been a demand for a desiccant that is inexpensive and has a high hygroscopic capacity but has a low risk of occurrence of metal rust and the like and has high safety.

Japanese Patent Laid-Open No. 10-76132 JP 11-156143 A

  However, in the conventional technique disclosed in the above patent document, when deliquescent inorganic salts such as calcium chloride are mixed with sepiolite or the like, sepiolite adheres to the surface of calcium chloride or the like, or calcium chloride or the like Is likely to be covered with the packaging material, and conversely, the moisture absorption capacity is said to be low. This is presumed that since halogen salts such as calcium chloride have a relatively high hygroscopic capacity, when used together with sepiolite or the like, they tend to adhere to the surface, which tends to cause a decrease in the hygroscopic capacity.

  In addition, even when a water retention agent such as sepiolite is used, if the salt comes into contact with a metal material as described above, it will remain a factor that causes corrosion such as rust, while maintaining moisture absorption capability and corrosion such as rust. There was a need to establish a technology that would resolve these concerns.

  The above-mentioned sepiolite is excellent in terms of water retention, but has a low hygroscopic capacity, so it is difficult to ensure a high drying capacity only with such a water retention agent.

  The present invention has been made in view of the above, and sodium acetate and / or potassium acetate, which is a non-halogen inorganic salt, is used, and there is a concern of occurrence of metal rust etc. while having low moisture and high hygroscopicity. An object is to provide a hygroscopic composition that is low and highly safe, and an object is to achieve the object.

Specific means for achieving the above object are as follows.
<1> Contains at least one of sodium acetate and potassium acetate and a water-absorbing binder, and a ratio of the total amount of sodium acetate and potassium acetate (Ac) to the amount of the water-absorbing binder (B) (Ac: B [ It is a hygroscopic composition whose mass ratio]) is in the range of 2: 3-4: 1.

  <2> The hygroscopic composition according to <1>, wherein the water-absorbing binder is at least one selected from the group consisting of clay minerals, water-absorbing polymers, and zeolites.

  <3> The hygroscopic composition according to <1> or <2>, wherein the ratio (Ac: B) is in the range of 2: 3 to 5: 2.

  <4> The hygroscopic composition according to any one of <1> to <3>, wherein the water-absorbing binder is at least one of sepiolite, carboxymethylcellulose, and an acrylic resin.

According to the present invention, sodium acetate and / or potassium acetate, which is a non-halogen inorganic salt, is used, and the hygroscopic property is low in safety and low in concern about the occurrence of metal rust and the like and has high safety. A composition can be provided.
Further, sodium acetate is used as a food additive, has low toxicity, suppresses the generation of halogen-based harmful substances when discarded, and has a low environmental load.

It is a graph which shows a time-dependent change of hygroscopicity when changing the mixing ratio of sodium acetate and sepiolite.

Hereinafter, the hygroscopic composition of the present invention will be described in detail.
The hygroscopic composition of the present invention contains at least sodium acetate and / or potassium acetate and a water-absorbing binder, and the ratio of the total amount of sodium acetate and potassium acetate (Ac) to the amount of the water-absorbing binder (B). (Ac: B [mass ratio]) is in the range of 2: 3 to 4: 1.

  In the present invention, sodium acetate and / or potassium acetate is used without using a halogen salt, and this sodium acetate and / or potassium acetate (Ac) together with the water-absorbing binder (B) is 2: 3 ≦ Ac: B ≦. By adopting a structure that satisfies the relationship of 4: 1 [mass ratio], it is possible to obtain better hygroscopicity than when sodium acetate or potassium acetate is used alone, and corrosion of metal materials (for example, Rust) is not only eliminated, but excellent moisture absorption efficiency is developed over a long period of time, and wetting or liquefaction that easily occurs with moisture absorption is less likely to occur. Thereby, it uses suitably as a hygroscopic composition (for example, desiccant) with respect to the to-be-dried material in which the metal material was used.

(Hygroscopic agent)
The hygroscopic composition of the present invention contains at least one of sodium acetate and potassium acetate as a hygroscopic agent. Sodium acetate and potassium acetate do not belong to halogen-based salts, and are inexpensive and difficult to cause metal corrosion (for example, rust). Therefore, they can be used regardless of the use of metal.

  Sodium acetate and potassium acetate are useful in that they have good moisture absorption and moisture absorption rate and are unlikely to cause liquefaction, and when used together with a water-absorbing binder, better hygroscopic ability is exhibited. Among these, sodium acetate is preferable in that the amount of moisture absorption is higher and liquefaction is less likely to occur. Moreover, the composition which used sodium acetate and potassium acetate together is also suitable.

  As a content rate in the total hygroscopic composition of sodium acetate and potassium acetate, the range of 20-80 mass% is preferable with respect to the total solid of a hygroscopic composition, More preferably, it is 30-70 mass%. It is a range. When the total content of sodium acetate and potassium acetate is 20% by mass or more, good hygroscopicity is obtained, and when it is 80% by mass or less, liquefaction is suppressed.

  The hygroscopic composition of the present invention may contain other hygroscopic agent together with sodium acetate and / or potassium acetate as long as the effects of the present invention are not impaired. Examples of other hygroscopic agents that can be contained in this case include silica gel (colloidal silicic acid), calcium oxide (quick lime), activated alumina (aluminum oxide), and the like. In the present invention, it is desirable not to include halogenated salts such as chlorides such as calcium chloride.

In the present invention, sodium acetate and / or potassium acetate (Ac) is in a ratio (Ac: B [mass ratio]) to a water-absorbing binder (B) described later so as to satisfy a range of 2: 3 to 4: 1. Contained.
When the ratio Ac: B is less than 2: 3, that is, the ratio of the total amount of sodium acetate and potassium acetate is too small, a liquid due to deliquescence hardly occurs due to a large amount of water-absorbing binder, but sodium acetate alone or potassium acetate alone Compared with the case of containing, the hygroscopic ability is lowered and the ability as a hygroscopic material is inferior. On the other hand, when the ratio Ac: B exceeds 4: 1, that is, when the ratio of the total amount of sodium acetate and potassium acetate is too high, the mixture gradually becomes wet and liquefies easily.
A preferable range of the ratio Ac: B is a range of 2: 3 to 5: 2 in terms of excellent hygroscopicity and hardly causing liquefaction, and more preferably in terms of being more difficult to wet. The range is 3 to 1: 1.

(Water-absorbing binder)
The hygroscopic composition of the present invention contains at least one water-absorbing binder. Sodium acetate and potassium acetate have deliquescence, and the hygroscopic ability of sodium acetate and potassium acetate can be enhanced by the presence of the water-absorbing binder in the above-mentioned predetermined ratio.

  Here, the water absorption means that the binder has the property of absorbing moisture chemically or physically, and specifically, the property capable of absorbing 10% by mass or more of moisture per unit mass of the binder. It means having.

  As the water-absorbing binder in the present invention, any inorganic or organic substance may be used as long as it has water absorption and can function as a binder capable of immobilizing sodium acetate or potassium acetate. Among these, preferred examples of the water-absorbing binder include clay minerals, water-absorbing polymers, and zeolites.

Examples of the clay mineral include sepiolite (hydrated magnesium silicate represented by Mg ₈ Si ₁₂ O ₃₀ (OH) _4. (OH ₂ ) ₄ .8H ₂ O) and attapulgite ((Mg · AL) ₂ Si _4. Hydrous magnesium silicate having a palygorskite structure represented by O ₁₀ (OH) · 4H ₂ O), kaolinite (aluminum silicate represented by Al ₂ (Si ₂ O ₅ ) (OH) ₄ ), perlite, dolomite, etc. Is mentioned.
Commercially available products may be used as the clay mineral, and sepiolite manufactured by Enomoto Kasei Co., Ltd., perlite manufactured by Ube Industries, Ltd., and the like can be used as examples of commercially available products.
You may use a clay mineral individually by 1 type or in combination of 2 or more types.

The water-absorbing polymer can be appropriately selected from water-absorbing resins. Examples of the water-absorbing polymer include acrylic resins (for example, sun fresh made by Sanyo Chemical Industries, Ltd.), cellulose resins (for example, carboxymethyl cellulose, etc.), and the like.
You may use a water absorbing polymer individually by 1 type or in combination of 2 or more types.

The zeolite is an aluminosilicate having a relatively large void in the crystal structure, and may be a natural zeolite or a synthetic zeolite. Examples of zeolite include β-zeolite, ZSM zeolite, A-type zeolite, X-type zeolite, Y-type zeolite and the like.
Moreover, a commercially available product may be used as the zeolite, and as an example of a commercially available product, zeolite manufactured by Shintohoku Chemical Industry Co., Ltd. can be used.
Zeolite may be used alone or in combination of two or more.

  The above-mentioned viscous minerals and zeolites are preferable in that they have an effect of adsorbing odor gas and can effectively remove amine-based gases such as ammonia, sulfide-based gases such as hydrogen sulfide, and corrosive gases such as formaldehyde gas.

A water absorbing binder may be used individually by 1 type, and may use 2 or more types together.
The content of the water-absorbing binder in the hygroscopic composition is not particularly limited as long as the ratio Ac: B is satisfied, but the following ranges are preferable.
As content in the hygroscopic composition of a water absorbing binder, the range of 20-80 mass% is preferable with respect to the total solid of a hygroscopic composition, More preferably, it is the range of 30-70 mass%. When the content of the water-absorbing binder is 20% by mass or more, an amount sufficient to receive moisture absorbed by sodium acetate and potassium acetate is secured, and the hygroscopicity of sodium acetate and potassium acetate is maintained over a long period of time. Further, if it is 80% by mass or less, it can be avoided that the amount of sodium acetate or potassium acetate is relatively reduced and the hygroscopic capacity is lowered.

(Other ingredients)
The hygroscopic composition of the present invention may contain other components such as a fluidizing agent and a preservative, if necessary, in addition to the components described above. What is necessary is just to contain the said other component in the range which does not impair the effect of this invention.

  The hygroscopic composition of the present invention can contain at least one fluidizing agent. By containing a fluidizing agent, it is possible to prevent the texture and solidification associated with moisture absorption and to exhibit good moisture absorption ability over a long period of time.

  Examples of the fluidizing agent include soft anhydrous silicic acid, talc, calcium stearate, magnesium stearate and the like.

A fluidizing agent may be used individually by 1 type, and may use 2 or more types together.
The content ratio of the fluidizing agent in the hygroscopic composition is preferably in the range of 0.2 to 10% by mass, more preferably based on the total solid content of sodium acetate and / or potassium acetate and the water-absorbing binder. Is in the range of 0.5-5% by mass. When the content of the fluidizing agent is 0.2% by mass or more, stickiness or solidification accompanying moisture absorption is prevented, and when it is 5% by mass or less, it is advantageous in that it is relatively inexpensive.

In the hygroscopic composition of the present invention, for example, sodium acetate and potassium acetate, a desired water-absorbing binder, and other additives such as a fluidizing agent and an antiseptic as necessary are mixed and made desirable. It can be prepared by leaving it under temperature and humidity conditions to adjust the water content.
Mixing may be performed using a mixer such as a stirrer or a kneader.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof.

Example 1
-Preparation of desiccant-
A desiccant was prepared as a hygroscopic composition by the following procedure.
Sodium acetate (hygroscopic agent) and sepiolite (PANGEL AD, manufactured by Enomoto Kasei Co., Ltd .; water-absorbing binder) were mixed at a ratio shown in Table 1 below so that the total amount of sodium acetate and sepiolite was 10 g. Further, 0.5 g of magnesium stearate (fluidizing agent) was added to prepare a desiccant sample. Thereafter, the obtained desiccant sample was filled in a petri dish, and the petri dish (with the top portion opened) was placed in a constant temperature and humidity chamber at 30 ° C. and 90% RH.

-1. Water absorption performance test
The desiccant sample obtained above was left for 2 days, 5 days, and 10 days under storage conditions of a temperature of 30 ° C. and a relative humidity of 90%. Then, the mass of the desiccant sample before storage and the mass of the sample after aging each day in the storage state were measured. From the measured values obtained, the amount of increase in mass was determined every number of days, and the moisture absorption was calculated according to the following formula. The test results are shown in Table 1 below.
Hygroscopicity [%] = mass increase [g] / sample amount [g] × 100

(Examples 2-11, Comparative Examples 1-10)
In Example 1, the ratio of the hygroscopic agent such as sodium acetate to the water-absorbing binder, the type of the hygroscopic agent, the type of the water-absorbing binder, etc. were changed as shown in Table 1 below, and the same as in Example Thus, a desiccant sample was prepared and a water absorption performance test was performed. Further, using the desiccant samples of Example 3 and Comparative Example 8, the following corrosion resistance test was performed. The test results are shown in Tables 1 and 2 below.

-2. Corrosion resistance test
After preparing iron material, copper material, stainless steel material (SUS material), and aluminum material as metal materials and degreasing each with acetone, the desiccant samples obtained in Example 3 and Comparative Example 8 were directly used for each metal material and its surface. And placed in a sealed container together with a beaker containing pure water and sealed with a lid. At the same time, a metal material without a desiccant was placed in a sealed container as a reference. Then, after standing at room temperature (25 ° C.) for 2 weeks, the surface condition of the metal material is visually observed, and the degree of corrosion associated with the occurrence of rust, etc., is compared with the reference in five stages of A to E. It was evaluated with.
At this time, the case where the surface state was the best was evaluated as “A”, and the case where the surface corrosion was greatest was evaluated as “E”. Here, “A” to “B” are allowable ranges for the corrosion resistance. The evaluation results are shown in Table 2 below.

Details of the components shown in Table 1 are as follows.
Sepiolite: PANGEL AD manufactured by Enomoto Kasei Co., Ltd.
CMC: CMC Daicel # 2260 (carboxymethylcellulose) manufactured by Daicel Chemical Industries, Ltd.
・ Zeolite: Zeophyl CP manufactured by Shin-Tohoku Chemical Industry Co., Ltd.
・ Perlite: Ube Perlite type 1 manufactured by Ube Industries, Ltd. ・ Silica gel: Silica gel manufactured by Wako Pure Chemical Industries, Ltd. Medium granular ・ Acrylic resin: Sunfresh ST-250 manufactured by Sanyo Kasei Co., Ltd.

As shown in Table 1, the examples containing sodium acetate or potassium acetate and a water-soluble binder component at a predetermined ratio are excellent in hygroscopicity, and even if some wetting is observed, they are liquefied and covered. There was no change that would adversely affect the dry matter. Moreover, as FIG. 1 shows, when the mixing ratio of sodium acetate or potassium acetate, and sepiolite is made into the predetermined ratio, it turns out that the moisture absorption by sodium acetate or potassium acetate changes favorably.
On the other hand, in the comparative example, the moisture absorption ability was low, and as the amount of moisture absorption increased, there was a tendency to wet or liquefy over time.

  As shown in Table 2 above, in the examples, compared to the comparative example using the chloride which is one of the salts, the corrosion on various metal materials was suppressed, and the metal surface was kept good.

  Moreover, although the said Example demonstrated centering on the case where sodium acetate or potassium acetate was each used independently as a hygroscopic agent, the substantially equivalent effect is acquired also when sodium acetate and potassium acetate are used together.

  The hygroscopic composition according to the present invention does not contain a halogen-based component and exhibits excellent hygroscopicity, but is unlikely to show a moist state accompanying deliquescence, and is therefore used for products containing metal materials such as precision instruments and parts. It can be suitably used for (especially use of a desiccant).

Claims (4)

  It contains at least one of sodium acetate and potassium acetate and a water-absorbing binder, and the ratio of the total amount of sodium acetate and potassium acetate (Ac) to the amount of the water-absorbing binder (B) (Ac: B [mass ratio] ) Is in the range of 2: 3-4: 1.   The hygroscopic composition according to claim 1, wherein the water-absorbing binder is at least one selected from the group consisting of clay minerals, water-absorbing polymers, and zeolites.   The hygroscopic composition according to claim 1 or 2, wherein the ratio (Ac: B) is in the range of 2: 3 to 5: 2.   The hygroscopic composition according to any one of claims 1 to 3, wherein the water-absorbing binder is at least one of sepiolite, carboxymethylcellulose, and an acrylic resin.