JPH06170148A - Moisture absorbent composition - Google Patents

Abstract

PURPOSE:To provide a moisture absorbent composition wherein fluidization caused by deliquescence of calcium chloride used as a moisture absorbent is prevented and moisture absorption velocity is large and furthermore moisture absorption effect and water retention effect are increased and also the same is mass-produced in a simple manufacturing process. CONSTITUTION:A moisture absorbent composition has a structure wherein calcium chloride is furthermore mixed with a mixture consisting of porous silica gel and calcium carbonate. Thereofore fluidity caused by deliquescence of calcium chloride is remarkably decreased and moisture absorption velocity is made remarkably large and moisture absorption effect and water retention effect are increased and the same is massproduced at a low cost in a simple manufacturing process.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a hygroscopic composition,
In particular, the present invention relates to a hygroscopic agent containing calcium chloride having an excellent hygroscopicity as an active ingredient, preventing fluidity due to deliquescent of calcium chloride, and having a large hygroscopic rate, a water absorbing effect, and a water retaining effect.

[0002]

2. Description of the Related Art Hygroscopic agents containing this kind of calcium chloride as an active ingredient have been widely used, but calcium chloride has fluidity due to deliquescent and becomes a liquid at the time of moisture absorption, which causes problems in handling. Since it adheres to the surrounding products and stains it, it has a drawback that the usable fields are extremely limited. In order to remedy this drawback, an invention as disclosed in Japanese Patent Laid-Open No. Sho 62-68526 has recently been developed. According to the present invention, in order to prevent the deliquescent property of calcium chloride, calcium chloride and water-absorbing powder are mixed to form a spherical shaped body, and further 30% is formed on the entire outer peripheral surface of the shaped body.
This is a technique of forming a porous coating layer using calcium silicate having a particle size of not more than μm to form particles.

[0003]

However, in producing a granular type moisture absorbent having such a constitution, calcium chloride and water-absorbing powder are mixed and then molded into a molded body, and then the Very fine around the molded body 30μ
Since the porous coating layer must be formed by applying calcium silicate of m or less, the manufacturing process is very complicated, mass production is difficult, and the cost is high. Further, very fine calcium silicate having a particle size of 30 μm or less must be produced by crushing granular calcium silicate, but there is a problem that enormous time and cost are required.

Further, the conventional hygroscopic agent according to the above-mentioned invention is
Since calcium chloride is coated with calcium silicate, there are problems that calcium chloride acts only indirectly, the moisture absorption rate is slow, and the moisture absorption effect is small. The hygroscopic agent composition according to the present invention is a technique developed in view of the above-mentioned conventional problems, and in particular, a porous silica gel and a calcium carbonate produced by using a method of carbonating porous calcium silicate or the like. It is a composition of a hygroscopic agent formed by further mixing calcium chloride into a mixture, and provides a completely novel hygroscopic composition having a high moisture absorption rate and a very large moisture absorption effect and water retention effect.

[0005]

The hygroscopic composition according to the present invention is a technique which has fundamentally improved the above-mentioned conventional problems, and the gist thereof is a mixture of silica gel and calcium carbonate, and a chloride. A moisture absorbent composition comprising a mixture containing calcium and, if necessary, porous calcium silicate, and the above 3 or 4 components obtained by carbonating porous calcium silicate It is a hygroscopic composition.

The moisture absorbent composition according to the present invention comprises calcium chloride and a mixture of silica gel and calcium carbonate capable of preventing deliquescent calcium chloride and having hygroscopicity and water retention itself. It is a mixture. As a result of experiments conducted by the present inventors over a long period of time,
A mixture of silica gel and calcium carbonate, particularly preferably, a mixture of silica gel and calcium carbonate obtained by carbonating porous calcium silicate is extremely hygroscopic and water retentive, and a mixture of these silica gel and calcium carbonate. It has been discovered that when calcium chloride is mixed with the above, the moisture absorption rate is remarkably increased as compared with the total amount of moisture absorption when the mixture of silica gel and calcium carbonate and calcium chloride are used alone.

Further, the mixture ratio of the above-mentioned porous silica gel and calcium carbonate for almost completely eliminating the fluidity of calcium chloride due to deliquescent and the mixing ratio of calcium chloride are humidity, temperature and other atmospheric conditions at the place of use. For example, silica gel 0.5 to 2.5 with respect to 1 part by weight of calcium chloride in an atmosphere of 25 ° C. and 90 RH% although it depends on
Parts by weight, 0.5 to 2.5 parts by weight of calcium carbonate, and more preferably 1 to 4 parts by weight of a mixture of silica gel and calcium carbonate in an approximately equal amount. Not shown, fluidity due to deliquescent calcium chloride can be substantially eliminated.

As a method for producing the mixture of silica gel and calcium carbonate, in addition to the method of mixing the respective constituents here, for example, silica gel and calcium carbonate obtained by carbonating porous calcium silicate are used. There is a way to do it. It should be noted that the presence of porous calcium silicate is excellent in the effect, and it is most preferable that the amount is about 2 to 10 parts by weight with respect to 1 part by weight of calcium chloride.

Various methods such as a reaction in an aqueous solution and a reaction in a carbon dioxide gas atmosphere are conceivable as the method for carbonizing the porous calcium silicate, but the method is not particularly limited as long as calcium carbonate and silica gel are formed. Further, the one in which the calcium content in the porous calcium silicate is completely carbonated is better because the amount of silica gel produced is larger and the moisture absorption rate is larger, but the calcium content in the porous calcium silicate is not always complete. It is not necessary to carbonate, and partially carbonized can also be used. The average particle size of the carbonic acid-treated porous calcium silicate is not particularly limited, but it is more preferable to use a powder having a particle size of 100 μm or more and 10 mm or less.

The porous calcium silicate suitable as a raw material for the moisture absorbent of the present invention is obtained mainly by a siliceous raw material and a calcareous raw material, which are preliminarily cured with a foaming agent, and then hydrothermally synthesized in an autoclave. It is what is done. Many porous calcium silicates are known, but the porous calcium silicate suitable as a raw material of the present invention is zonotolite, tobermorite, gyrolite, foshajite, hirebrandite, etc. It is known. These porous calcium silicates need not be used alone, but can be used as a mixture of two or more kinds. Further, these porous calcium silicates may not be completely pure, and may contain CSH gel and unreacted siliceous raw material.

Among the porous calcium silicates, lightweight cellular concrete (ALC), which is generally used as a building material, is relatively easy to obtain as a material, and the composition of the present invention has a proper hygroscopicity and water retention. It is preferable because it has properties. It is not necessary to use a new product, ALC
It is also possible to crush and use a defective product generated in the manufacturing process, a scrap material generated at a construction site such as a building or a house, which has been conventionally discarded, into an appropriate size.

[0012] According to this method, calcium carbonate and silica gel are produced, and the moisture absorption performance is improved. However, since a part of the original porous calcium silicate retains its shape and components as it is, it is more excellent in water retention. It became clear that The mixture of porous silica gel and calcium carbonate thus obtained, which is a mixture of calcium chloride and porous calcium silicate, can reduce the fluidity of moisture-absorbed calcium chloride and increase the moisture absorption rate.

[0013]

As described above, the hygroscopic composition according to the present invention can be prepared by mixing calcium chloride and, if necessary, porous calcium silicate into a mixture of silica gel and calcium carbonate. After molding, there is no need to laminate a coating layer of calcium silicate powder on this surface, mass production is possible with a simple manufacturing process, and since it is not a laminated structure, calcium chloride, silica gel and Since each calcium carbonate is exposed on the outer surface, a hygroscopic composition having an extremely high moisture absorption rate can be obtained. Since the hygroscopic agent composition of the present invention is a mixture of silica gel and calcium carbonate mixed with calcium chloride, the deliquescent property of calcium chloride can be prevented, and a hygroscopic agent composition excellent in hygroscopicity and water retention can be obtained. You can By mixing an appropriate amount of porous calcium silicate with a mixture of silica gel, calcium carbonate and calcium chloride, more excellent deliquescent prevention property, hygroscopicity and water retention can be obtained.

[0014]

EXAMPLES The present invention will be described in more detail with reference to specific examples, comparative examples and reference examples. In addition, the powder obtained by treating the ALC with carbon dioxide used in the examples and the reference examples is completely carbonized with a carbon content by leaving the ALC powder crushed to 2.0 mm or less in a carbon dioxide atmosphere. The calcium powder was left to stand in a dryer at 105 ° C. until a constant weight was used. The average particle size of these particles was 1.5 mm, and particles having a particle size of 100 μm or less were substantially absent.

[0015]

Example 1 ALC powder was treated with carbon dioxide gas in 4 g of anhydrous calcium chloride and then dried at a temperature of 110 ° C. to a constant weight. The composition of components in the powder obtained at this time was 20% calcium chloride, 15% silica gel, 1 calcium carbonate.
5% and 50% of the remaining porous calcium silicate. 16g of this powder is put in a container and kept at 25 ° C, 90RH%
It was left under the humidity of 16 days. Then, the weight change was measured and the moisture absorption rate was calculated. At this time, the moisture absorption of the mixture is 2
It was 1.8 g. The moisture absorption amount of anhydrous calcium chloride alone after 16 days was 3.87 g / g, and the moisture absorption amount of the powder obtained by treating the ALC powder with carbon dioxide gas was 0.09 g / g. It was found that 5 g was excessively absorbed, and the moisture absorption rate was remarkably high.

[0016]

Example 2 ALC powder was treated with carbon dioxide gas in 2 g of anhydrous calcium chloride and then dried at a temperature of 110 ° C. until a constant weight was obtained. The composition of components in the powder obtained at this time was 10% calcium chloride, 8% silica gel, and 8% calcium carbonate.
%, And the remaining porous calcium silicate was 74%. 18 g of this powder was put in a container and the same operation as in Example 1 was performed. As a result, the amount of moisture absorption of the mixture was 12.5 g, which means that excess moisture was absorbed by 3.0 g in the calculation method as in Example 1, and it was found that the moisture absorption rate was high as in Example 1. did. Also, the mixture after 16 days had no fluidity.

[0017]

Example 3 ALC powder was treated with carbon dioxide in 8 g of anhydrous calcium chloride and then dried at a temperature of 110 ° C. until a constant weight was obtained. The composition of components in the powder obtained at this time was as follows: calcium chloride 40%, silica gel 20%, calcium carbonate 2
0% and the remaining porous calcium silicate was 20%. 12g of this powder is put in a container, 25 ° C, 90RH%
It was left under the humidity of 3 days. Then, the weight change was measured and the moisture absorption rate was calculated. At this time, the moisture absorption of the mixture is 19.0 g.
Met. The moisture absorption of anhydrous calcium chloride alone after 3 days was 1.82 / g, and the moisture absorption of ALC powder alone was 0.09 g / g.
Since it absorbs excessive moisture, it can be said that the moisture absorption rate is high as in Example 1. Also, the mixture after 3 days was not fluid.

[0018]

Comparative Example 1 20 g of anhydrous calcium chloride was placed in a container,
The same operation as in Example 1 was performed. The moisture absorption after 3 days is 3
It was 6.4 g, and the moisture absorption amount after 17 days was 77.4 g. Regarding fluidity, it began to deliquesce at the start of the test, and after 24 hours, it became a fluid calcium chloride solution.

[0019]

[Reference Example 1] After only ALC powder was treated with carbon dioxide gas, 1
20 g of powder that had been dried to a constant weight at a temperature of 10 ° C. was placed in a container, and the same operation as in Example 1 was performed. The amount of moisture absorption is
It was 1.8 g after 3 days, and was measured 10 days later and 16 days later, but there was no increase in moisture absorption.

[0020]

EFFECTS OF THE INVENTION The hygroscopic composition according to the present invention has the above-mentioned constitutions and effects, so that it prevents fluidity due to deliquescent calcium chloride after moisture absorption, and also significantly increases the moisture absorption rate, It has hygroscopicity and water retention. Moreover, since it is not necessary to mold calcium chloride into a spherical shape or to cover the entire outer surface of the calcium chloride molded body with calcium silicate or the like, mass production can be carried out inexpensively in a simple process.

Porous calcium silicate does not need to be pulverized extremely finely, and it can be used by mixing the granules as they are with calcium carbonate and subjecting them to carbonation. Moreover, the water-retaining effect and the chlorination are greater than those obtained when pulverized. The effect of preventing deliquescence of calcium can be obtained. Further, since calcium chloride, porous silica gel, and calcium carbonate are exposed as they are on the outer surface, respectively, the moisture absorption rate can be increased, and the synergistic effect can remarkably enhance the moisture absorption effect. .

Claims (2)

[Claims] 1. A hygroscopic composition comprising a mixture of silica gel and calcium carbonate, and a mixture containing calcium chloride and, if necessary, porous calcium silicate. 2. The hygroscopic composition according to claim 1, wherein the 3 or 4 components are obtained by carbonizing porous calcium silicate.