JPH0470926B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a moisture absorbent composition mainly composed of calcium chloride for absorbing moisture in the air. The present invention relates to a moisture absorbent composition that maintains a softened and gelled state for a long time and does not cause liquid leakage due to pinholes in packaging materials or small scratches caused when the packaging material is dropped. BACKGROUND ART In recent years, due to changes in housing structures, indoor airtightness has increased, and various harmful effects caused by the growth of mold have become a problem. As a countermeasure to these problems, many products are now on the market that are filled with moisture absorbing agents such as silica gel and calcium chloride in containers and bags for dehumidifying and drying closets, cupboards, shoe cabinets, tea rooms, storerooms, etc. I'm getting old. For example, a moisture absorbent is sealed and stored in a molded plastic container, which is opened and closed during use;
Some use bags made of breathable sheets that do not allow water to pass through. In addition, a breathable, non-breathable sheet is used on the back side, and a non-breathable, transparent film is used on the surface to make it possible to clearly see the moisture absorption status. There are also products on the market that are made into a shape. Problems to be Solved by the Invention Calcium chloride has superior moisture absorption ability compared to other moisture absorbents such as silica gel, and therefore is the most effective moisture absorbent for use in moisture absorbent compositions. However, a saturated solution of calcium chloride has extremely high surface tension, and once spilled on a table or shelf, it cannot be wiped off with tissue paper. For this reason, it is essential that dehumidifier products using calcium chloride do not leak. However, as mentioned above, conventional dehumidifier products are packaged in plastic containers, but they have the inconvenience of spilling the contents if they are accidentally knocked over, and polymer film packages with moisture-absorbing sheets do not contain liquid. Although they do not leak, if holes are made due to external factors, fluid leaks as well, which is inconvenient for consumers. In addition, in the case of products where the desiccant becomes sticky after absorbing moisture, as mentioned above, the moisture absorption status can be clearly seen, but since a large amount of gelling agent is blended, the moisture absorption rate is slow and the amount of moisture absorbed is extremely small. There are also
In practical terms, the product has not yet satisfied consumers. On the other hand, according to the research conducted by the present inventors, calcium chloride solidifies extremely hard at the initial stage of moisture absorption, so when using film packaging materials, the same strength as when using sand or ice is required. This was confirmed by a drop test. Furthermore, once the calcium chloride aqueous solution has passed through the initial stage of moisture absorption and becomes a liquid, recrystallization of calcium chloride occurs at night due to the temperature difference between day and night. It was discovered that phenomena such as bag breakage occur when the body falls. Such a phenomenon promotes breakage, perforation, etc. of the film package, and often causes the problem of liquid leakage. Therefore, an object of the present invention is to prevent the above-mentioned solidification of calcium chloride at the initial stage of moisture absorption and subsequent recrystallization, and to prevent pinholes in the film packaging or perforation caused by external factors, as well as from overturning of the container. It is an object of the present invention to provide a moisture absorbent composition that does not cause liquid leakage even when it is used. Means for Solving the Problems In order to achieve the above object, the present invention provides calcium chloride and at least one gelling agent selected from the group consisting of alkylene oxide adducts of lambda-type carrageenan and α-starch. The moisture absorbent composition contains 5 to 20 parts by weight of a gelling agent per 100 parts by weight of calcium chloride. Effects and Modes of the Invention In order to prevent the bag from being easily broken when dropped due to the solidification and recrystallization phenomenon of calcium chloride in the early stage of moisture absorption, when using a film packaging material, it is necessary to increase the strength of the film. is the usual method, but it cannot be solved with the current film materials. Therefore, in order to prevent liquid leakage due to overturning of the container or breakage of the film package, it is most effective to gel the calcium chloride aqueous solution after moisture absorption by some means. The present inventors have discovered that when calcium chloride powder or granules are made to coexist with a specific substance, the calcium chloride aqueous solution produced by moisture absorption quickly turns into a soft gel due to the action of the above substance, and it becomes a soft gel from the initial stage of moisture absorption until the end of moisture absorption. It was discovered that calcium chloride can be maintained in a solidified state, thereby preventing calcium chloride from solidifying at the initial stage of moisture absorption, and also preventing recrystallization by forming a soft gel. It is extremely difficult to convert an aqueous solution of calcium chloride into a soft gel due to the large surface tension of the aqueous calcium chloride solution, and as shown in Table 1 below,
It hardly gels with ordinary gelling agents. The present inventors investigated various gelling agents by type, and as a result, as shown in Table 1,
Two materials have been found to be effective: random carrageenan and an alkylene oxide adduct of alpha-starch.

【table】

[Table] In the test example shown in Table 1 above, in the case of a gelling agent that did not gel at all even when 5% was added to a saturated calcium chloride solution, no gelation occurred even when 10% or more of the gelling agent was added. Ta. As is clear from Table 1 above, four types, random carrageenan, α-starch alkylene oxide adduct, and konjac mannan, have the ability to gel a saturated calcium chloride solution, but konjac mannan is expensive. Therefore, it has the disadvantage that it is difficult to use economically. Lambda-type carrageenan has the strongest ability to gel a saturated calcium chloride solution, and alkylene oxide adducts of α-starch also exhibit strong gelling ability, so from a practical standpoint, it is preferable to use these two types. . The breathable film used for enclosing or accommodating/packaging the gelling agent and calcium chloride moisture absorbent must have the property of allowing water vapor to pass through but not water. In general, this breathable film has minute holes that allow humid air to pass through, but the structure is such that water does not pass through it due to its large surface tension. . When the above three types of gelling agents were contained in this film, it was investigated whether liquid leakage from the breathable film would occur due to the influence of the gelling agents. The experimental method involved adding 1%, 3%, 5%, and 10% of various gelling agents to 300 g of calcium chloride, storing the mixture in a bag partially covered with the above-mentioned breathable film, sealing it, and then heating it at 40°C. It was stored and observed in a constant temperature and humidity room at 75%. As a result, no liquid leakage phenomenon occurred in any of the samples. Various performance and characteristic tests were conducted on the above two preferred gelling agents, which are shown below. Test example 1 (Effect on viscosity of gelling agent) Saturated calcium chloride solution (calcium chloride 100
The viscosity of each gelling agent was measured when the gelling agent was added in various amounts to a solution obtained by adding 100 g of water to 100 g of water and dissolving it. The results are shown in Table-2. The viscosity was measured using a B-type viscometer (manufactured by Tokyo Keiki).
The viscosity of a saturated calcium chloride solution at a temperature of 25°C was 35 cP.

[Table] The target substance is emulsifier Nonipol 100 [product, manufactured by Sanyo Chemical Industries, Ltd., (chemical structural formula, The viscosity of the formulation examples was measured, and the values were lower than the viscosity of saturated calcium chloride solution, and when the solution was placed in a breathable film packaging material and a pinhole was pierced with a needle, liquid leakage occurred in all cases. did. On the other hand, no liquid leakage phenomenon was observed for each of the gelling agent formulation examples that exhibited higher viscosity values than the saturated calcium chloride solution. Test Example 2 (Status of Soft Gelation) The degree to which the gelling agent softens the preparation during initial moisture absorption of calcium chloride was measured by applying pressure after a certain moisture absorption time, and the solidified calcium chloride was The pressure that changed beyond the pressure resistance limit was read and determined. The experimental method involved filling a predetermined amount of each mixture of calcium chloride and gelling agent into a certain bag, and heating it at 40°C.
Each sample that has been left in a constant temperature and humidity room at 75% to absorb approximately 100 g of moisture and harden is pressed little by little using a press, and the pressure at which the pressure reaches its highest value (pressure resistance limit point) is determined. deciphered. The softer the gel, the lower the value. The results are shown in Table-3. In addition, the numerical value shows the average value of two measurements.

[Table] As is clear from Table 3 above, gelling agent 3%
Although the blended formulation exhibits a somewhat soft gel state, it appears that a blending ratio of 5% or more is required to obtain good results. Test Example 3 (Leakage Prevention Effect) Suppose that pinholes, etc. occur due to external factors when using a package that uses a breathable film as a part of the package, and the formulations 1 to 3 in Table 4 below are used. The leakage status of the moisture absorbent was investigated. As an experimental method, a mixture of each of the gelling agents of formulations 1 to 3 below and calcium chloride (calcium chloride only in formulation number 8) was housed in a package, and 40
After leaving the bag in a constant temperature and humidity room at 75% °C and absorbing about 100g of water, use a needle to make a small hole in a part of the non-breathable film of the bag to check for liquid leakage from inside. Observation was made with the naked eye. The results are shown in Table-4.

[Table] From the results shown in Table 4 above, it was found that the addition amount of 3% was somewhat unstable. Additionally, lambda-type carakeenan best prevented liquid leakage, and a mixture of α-starch with an alkylene oxide adduct also showed good results. Test Example 4 (Effect of Preventing Precipitation of Crystals) It was investigated whether the gelling agent has the ability to prevent precipitation of crystals in a calcium chloride solution due to a drop in the outside temperature. The results are shown in Table-5. The experimental method used was a saturated aqueous solution of calcium chloride (200 g of calcium chloride to 100 g of water).
Add and dissolve a solution) and lower the temperature of this solution to 25
After adding the substances of Prescriptions 1 to 3 in the respective amounts and stirring, the state of precipitation of crystals was visually determined when the mixture was cooled to a temperature of 10°C.

[Table] From the results shown in Table 5 above, any gelling agent has an effect of preventing recrystallization when added in an amount of 10% or more. Test Example 5 Appropriate amount of gelling agent to be added to product The appropriate amount of gelling agent to be added to calcium chloride was studied. The results are shown in Table-6. In addition, as for the experimental method, calcium chloride 250
g and 5 to 30% of a gelling agent (a 1:1 mixture of lambda-type carrageenan and alkylene oxide adducts of α-starch), each of which was made into a standing pouch type using a breathable film in a part. After storing it in a bag, seal it and store it at 40℃ and 75℃.
% in a constant temperature/humidity room and observed the moisture absorption state.

【table】

[Table] From the results shown in Table 6 above, when the addition amount is 25% or more, the gel hardness becomes stronger than intended. In addition, the moisture absorption rate is slow at 20%, and at 30%, it is so slow that it has almost no practical value as a moisture absorbent. Considering the features and economy of this product, 20%
Although it can still be made into a product even with the amount added above, 15%
The front and back seems to be the best. Examples Hereinafter, the effects of the present invention will be specifically explained with reference to Examples. Example 1 250g of calcium chloride was weighed and placed in a standing pouch-type packaging bag partially made of a breathable film (a film made by laminating non-woven fabric on both sides of a microporous film), then sealed and used as a standard sample. did. Separately, 250 g of calcium chloride and a certain amount of the gelling agent shown in Table 7 were weighed, stirred and mixed in a milk funnel, placed in the same standing pouch-type packaging bag as above, and sealed. And so. These samples were stored in a constant temperature/humidity room at 40°C and 75%, and the amount of water supplied was measured and the state of gelation was observed. The results and the formulation of the gelling agent are shown in Table 7.

[Table] The moisture absorbents of sample numbers 1 to 4 were all smoothly turned into soft gels. When a hole was artificially made from the outside with a needle in the part that had become a soft gel, no liquid leakage occurred. In contrast, in the case of the standard sample, calcium chloride was in the form of an aqueous solution, and when a hole was punctured with a needle, the solution leaked. Example 2 Weighed 300 g of calcium chloride, placed it in a standing pouch-type packaging bag partially made of a breathable film (a film made by laminating nonwoven fabric on both sides of a microporous film), and then sealed it and used it as a standard sample. did. Separately, after weighing a certain amount of various gelling agents shown in Table 8, put it into the bottom of the same standing pouch-type packaging bag as above, and then add 300% of calcium chloride.
g was weighed and placed on top of the sample, and then sealed to obtain a test sample. These samples were stored in a constant temperature/humidity room at 40°C and 75%, and the amount of water supplied was measured and the state of gelation was observed. The results and the formulation of the gelling agent are shown in Table 8.

[Table] In the moisture absorbers of sample numbers 1 to 4, the gelling agent is added to the bottom of the standing pouch type packaging bag, so the bottom part gels and the top part is not completely gelled. Some aqueous solution of calcium chloride was floating. On the other hand, in the case of the standard sample, calcium chloride became an aqueous solution, and as days passed, the aqueous solution of calcium chloride accumulated at the top. In addition, in the case of sample numbers 1 to 4, the moisture absorbent gels at the bottom and expands, pushing calcium chloride upward, increasing the contact area with the breathable film and increasing the amount of water supplied compared to the standard sample. In particular, the moisture absorbents of sample numbers 1 and 2 had a considerably large amount of water supplied even after 45 days. Effects of the Invention The moisture absorbent composition according to the present invention contains calcium chloride and at least one gelling agent selected from the group consisting of lambda-type carrageenan and alkylene oxide adducts of α-starch. Since it is contained in a ratio of 5 to 20 parts by weight of gelling agent to parts by weight, it has the following characteristics. (1) Prevents calcium chloride from solidifying during initial moisture absorption. (2) Shows a soft gel state from the beginning to the end of moisture absorption. (3) Preventing precipitation of crystals due to outside temperature differences in calcium chloride solution. As a result, the liquid content will not leak even if there are minute cracks or holes in the package when the product is dropped, or if the packaging container falls over.Therefore, there is no need for an expensive breathable film to prevent liquid leakage, and the product can be used easily. It has unique effects such as being able to use a breathable film and having the same amount of moisture absorption as calcium chloride alone.

Claims (1)

[Claims] 1 Calcium chloride and at least one gelling agent selected from the group consisting of lambda-type carrageenan and alkylene oxide adducts of α-starch are added in an amount of 5 to 20 parts by weight of the gelling agent per 100 parts by weight of calcium chloride. A moisture absorbent composition comprising: