JP3404232B2 - Manufacturing method of cool and heat insulator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a cold / heat retaining agent.

[0002]

2. Description of the Related Art It is well known that dry ice or ice is widely used as a cooling agent, but in recent years, the temperature is adapted to the object to be cooled, the economical efficiency of repeated use and the high leakage resistance. The need for viscosity safety is increasing, and it is difficult to meet such demands only with dry ice or ice. Recently, in order to solve these problems, a bag made of polyethylene or the like is filled with a gel-like material,
The frozen product has been widely used as a cooling agent.

The gelling agent for filling the cold insulating bag is a highly viscous aqueous solution of a water-soluble polymer such as carboxymethyl cellulose, starch, polyvinyl alcohol, sodium polyacrylate, polyacrylamide, sodium alginate, or a water-soluble polymer thereof. A hydrous gel-like material that is crosslinked with an inorganic salt such as borate or an organic crosslinking agent is used.

Particularly, the cold-preserving agent consisting of a water-soluble gel of carboxymethylcellulose polyvalent metal salt described in JP-A-2-180988 discloses a gel-like substance even if bag breakage occurs during distribution, food, etc. Does not adhere even if it comes into contact with
It is a gel-like material that does not have fluidity and tackiness, and is a stable gel-like material that does not cause viscosity reduction or water separation due to light, etc. . Further, the water-soluble gel of carboxymethyl cellulose polyvalent metal salt has high utility value even when used as a heat retaining agent without deterioration due to repeated use.

[0005]

However, cold storage using carboxymethyl cellulose polyvalent metal salt as a main raw material
When manufacturing a heat retaining agent, generally, the following three types of methods are performed.

The first is to dissolve powdery carboxymethylcellulose (carboxymethylcellulose is a monovalent salt such as sodium carboxymethylcellulose, potassium carboxymethylcellulose and ammonium carboxymethylcellulose: hereinafter abbreviated as CMC) in water, and then dissolve it in a large amount. A method of adding a valent metal salt.

The second method is to dissolve a polyvalent metal salt in water and add powdery CMC. Third, powder CM
A method in which C and a polyvalent metal salt are mixed and added to water. However, in any case, during the process of dissolving the powdered CMC in water and an aqueous solution, mamako was easily formed, and mechanical stirring and long time were required to form a uniform gel.

Further, a step of transferring the produced gel by a high pressure pump or the like and filling the bag is required. Therefore, even if it is a main raw material suitable as a cold / heat-retaining agent, the manufacturing process is complicated and the construction cost is high and it is not economical. Therefore, there is a demand for a manufacturing method having good productivity and capable of adjusting the heat-retaining / cooling agent at low cost. .

[0009]

The present invention has been made in view of such conventional problems. That is, the first gist of the present invention is that the (a) polyvalent metal salt aqueous solution and (b) 1% aqueous solution viscosity at 25 ° C. (hereinafter, simply referred to as viscosity) are 50 to 10000 mPa · s in a tare, .1m
containing 50% by weight or more of particles having a particle size of m or more, and 2.0
Cooling characterized by sealing the tare after filling with granular carboxymethylcellulose (hereinafter abbreviated as granular CMC) containing 70% by weight or more of mm or less
It is a method of manufacturing heat retaining agent,

A second gist is that the sheet-shaped tare material is automatically supplied to a filling machine capable of forming the tare material into a tubular shape to form a tubular body, and the lower portion of the tubular body is sealed to form the tare. After molding, the tare contains (a) an aqueous solution of a polyvalent metal salt and (b) 50% by weight or more of a viscosity of 50 to 10,000 mPa · s and a particle size of 0.1 mm or more, and 2.0 mm. A method for producing a cold-retaining / heat-retaining agent, which comprises filling granular CMC containing 70% by weight or more of the following, and then sealing the upper part of the tare.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, important matters will be divided into items and described based on the embodiments of the present invention. (1) Aqueous solution of polyvalent metal salt The aqueous solution of polyvalent metal salt used in the present invention acts as a mamaco inhibitor, and the polyvalent metal salt as a component thereof is preferably composed of, for example, aluminum, iron, calcium and barium. It is at least one metal salt selected from the group.

As the aluminum salt, for example, potassium alum, burnt alum, aluminum acetate, aluminum sulfate and the like can be used. As the iron salt, for example, ferric chloride, ferrous sulfate, etc. can be used. As the calcium salt, for example, calcium hydroxide or the like can be used. As the barium salt, for example, barium chloride or the like can be used. However, the aluminum compound is preferable, judging from the fact that the coloring peculiar to the metal salt is recognized and the economy.

The polyvalent metal salt is dissolved in water in advance and used as an aqueous solution. The aqueous solution concentration of the polyvalent metal salt is not particularly limited and may be appropriately selected each time. When the polyvalent metal salt is dissolved in water in advance, when granular CMC is added to the aqueous solution,
A carboxymethylcellulose polyvalent metal salt is formed at the interface between the granular CMC and the aqueous solution, the solubility in water is reduced, local gelation is suppressed, and the granular CMC is uniformly swollen without mamko. This allows granular CM
A uniform gel obtained by mixing C and water can be obtained without requiring physical force such as stirring or kneading with a kneader.

(2) Granular CMC Next, the granular CMC has a viscosity of 50 to 10 as described above.
000 mPa · s, preferably 200 to 10,000 mP
It is a granular material containing 50% by weight or more of particles having an a · s of 0.1 mm or more and 70% by weight or more of particles having a particle size of 2.0 mm or less.

These physical properties will be described in detail.
When it is less than 0 mPa · s, it easily dissolves in water, and mamasuko occurs. When it exceeds 10000 mPa · s, it has a high viscosity by itself, and even if it is added to an aqueous solution in which a polyvalent metal salt is dissolved, the dispersed state is poor and a uniform gel cannot be obtained. The 1% aqueous solution viscosity means granular CMC.
60% of 1% aqueous solution of BM using a BM type viscometer
Viscosity as measured in pm.

If the particle size is less than 0.1 mm, 50
When it is contained in an amount of not less than 5% by weight, the surface area of the granular CMC becomes large, and when put into water, a gel is instantaneously formed on the contact surface with water and mammico occurs. On the other hand, the particle size is 2.0 mm
If more than 30% by weight is contained, the surface area becomes too small and the dissolution rate in water becomes extremely slow, which is not economically suitable.

Further, in the granular CMC, the average degree of substitution of carboxymethyl groups (hereinafter abbreviated as DS) is preferably 0.30 to 2.00. When DS is less than 0.30, it is difficult to dissolve in water, and when it exceeds 2.00, intramolecular cross-linking preferentially progresses when gelled with polyvalent metal ions because many carboxymethyl groups are present in the molecule. The produced gel has a high cross-linking density, is easy to separate water, and is not suitable as a heat retaining agent.

(3) Other Ingredients In the present invention, in addition to the above, in the present invention, bitterness imparting agents, preservatives, coloring agents, and polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin, and sorbitol for controlling the freezing temperature. May be added as appropriate.

(4) Tare The tare including the uniform gel is preferably made of a thermoplastic resin for sealing with a seal. More preferably, for example, polyvinyl chloride or a copolymer thereof,
Polyvinylidene chloride copolymer, polyethylene, polypropylene or polyurethane, natural or synthetic rubber, etc. as a raw material, and the normal freezer temperature (-15 to 15
It is a polymer material such as a film or a sheet that does not cure at -25 ° C. and has low water vapor permeability.

(5) Manufacturing Method Next, a method of manufacturing the cold / heat retaining agent of the present invention will be described. The invention is first to tare the polyvalent metal salt aqueous solution and granular CMC. The addition order of both components is not particularly limited, and either one or both may be added at the same time.

The amount of the polyvalent metal salt aqueous solution added is such that the polyvalent metal salt contained in the cold / heat retaining agent is 0.05 to 10% by weight, preferably 0.10 to 1.00% by weight. . When the content of the polyvalent metal salt is less than 0.05% by weight, when the granular CMC is added to the aqueous solution of the polyvalent metal salt, the ratio of the polyvalent metal ion ionically bonded to the carboxymethyl group at the interface between the granular CMC and the aqueous solution. Since the amount is small, the solubility in water does not decrease, local gelation occurs, and mamako is formed.
On the other hand, when the content of the polyvalent metal salt exceeds 10% by weight, granular CMC becomes insoluble in the aqueous solution, causing water separation.

The other component, granular CMC, is added in such an amount that the CMC contained in the cold / heat retaining agent is 1 to 10% by weight. If it is less than 1% by weight, it is difficult to obtain an aqueous gel having a desired hardness, and if it exceeds 10% by weight, the viscosity becomes extremely high and a uniform gel cannot be obtained, which is unsuitable as a heat-retaining agent. In addition, it causes cost increase and is not economically preferable.

Next, after filling both components, the tare is sealed with a seal or the like and left to stand in order to form a uniform gel. The standing temperature at this time is not particularly limited. After standing, the desired excellent cold / heat retaining agent is obtained. Conventionally, stirring was required to generate a uniform gel in this step, but such a step is not necessary in the present invention.

Further, in the present invention, continuous production using a filling machine such as "Aqua 500" and "Aqua 2000" (automatic filling and packaging machine: manufactured by Chuo Wrapping Machine Co., Ltd.) is also possible. Specifically, the upper part of the tare is first sealed with the lower part sealed inside the filling machine. The sheet-shaped tare material is wound around a guide tube, formed into a tube shape at the tube seal portion, and the bottom portion of the tare is formed at the lateral seal portion to form an open-tare tare.
To the tare, (a) the polyvalent metal salt aqueous solution is supplied from the supply pipe, and at the same time, (b) the granular CMC is supplied through the solid supply pipe. The tare is filled with a certain amount and the supply is temporarily stopped. Next, the deaeration plate pushes both sides of the tare, the tare moves downward while letting air escape upward, and the upper lateral seal is made by the lateral seal portion and sealed. Then remove from the filling machine and let stand. After standing, the desired excellent cold / heat retaining agent is obtained.

[0025]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded. In the examples,% is based on weight.

Examples 1-15 and Comparative Examples 1-4. Add a predetermined amount of potassium alum solution to the tare (material: polyethylene film). Next, a predetermined amount of granular CMC is added and filled, and then the tare is heat-sealed and hermetically sealed. The cold and heat retaining agent thus obtained was allowed to stand for 1 day or 2 days as it was, and then the gel state was observed and judged visually and by touch with the hands.

Example 16 and Comparative Example 5. A cold / heat-retaining agent was manufactured using the filling machine "Aqua 2000" (automatic filling / packing machine: manufactured by Chuo Wrapping Machine Co., Ltd., trade name) shown in FIG. First, the tare material (polyethylene film) S is wound around the guide tube 1 and formed into a tubular body S ′ by the tube seal portion 4, and the bottom portion of the tare is formed by the lateral seal portion 7. A predetermined polyvalent metal salt aqueous solution is supplied from the supply pipe 3 to the open tare S ″, and at the same time, a predetermined granular CMC is supplied from the supply mechanism 5 through the solid supply pipe 2. Next, the degassing plate 6, 6, push both sides of the tare S ″, move the tare S ″ downward while letting air escape upward, and after the upper horizontal seal is made by the horizontal seal portion 7, take out from the filling machine. The rate was 20 bags / minute.

All the above results are shown in Tables 1, 2 and 3. The terms in the table have the following meanings. Gel state (judged by visual inspection and touch by hand); x: Mamako remains after standing for 2 days. ◯: A uniform gel is obtained after standing for 2 days. A: A uniform gel is obtained after standing for 1 day.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

According to the production method of the present invention, by adding granular CMC to an aqueous solution in which a polyvalent metal salt is dissolved in water in advance, the generation of mamako is prevented and the granular CMC swells uniformly. . As a result, a uniform gel obtained by mixing the granular CMC and water can be obtained without requiring physical force such as stirring or kneading with a kneader, and a cold / heat retaining agent can be easily and economically obtained. .

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an internal structure of a filling machine suitable for carrying out the method for producing a cold / heat retaining agent according to the present invention.

[Explanation of symbols]

1 Guide tube 2 Solid supply pipe 3 supply pipes 4 Tube seal part 5 supply mechanism 6 degassing board 7 Horizontal seal part S tare material S'cylindrical body S ”tare

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-2-180988 (JP, A) JP-A-7-90121 (JP, A) JP-A-54-160460 (JP, A) JP-A-58- 90519 (JP, A) JP-A-8-178495 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09K 5/00 101 A61K 7/10 311 C09K 5/06

Claims (3)

(57) [Claims] 1. A tare of (a) polyvalent metal salt aqueous solution and (b) 1% aqueous solution viscosity at 25 ° C. of 50 to 1000.
At 0 mPa · s, 50% by weight or more of particles having a particle size of 0.1 mm or more and 70% by weight of particles having a diameter of 2.0 mm or less
A method for producing a cold-preserving / heat-retaining agent, which comprises filling the above-mentioned granular carboxymethyl cellulose and then sealing the tare. 2. A sheet-shaped tare material is automatically supplied to a filling machine capable of forming the tare material into a tubular shape to form a tubular body, and the lower portion of the tubular body is sealed to form a tare. In the tare, (a) polyvalent metal salt aqueous solution and (b) 1 at 25 ° C.
% Aqueous solution has a viscosity of 50 to 10,000 mPa · s and is 0.1
1. Contains 50% by weight or more of particles having a particle size of mm or more, and 2.
A method for producing a cold-retaining / heat-retaining agent, which comprises filling granular carboxymethyl cellulose containing 70% by weight or more of 0 mm or less and then sealing the upper part of the tare. 3. The method for producing a cold-keeping / heat-retaining agent according to claim 1, wherein the polyvalent metal salt is an aluminum salt.