JP2003096238A - New gel, gelatinous coolant composition using the same and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain gel that can be handled as a solid substance at a temperature in its actual use of 0 to 30 deg.C and mixed together with water and other solvents as a solution is. SOLUTION: The gel contains one or more solvents selected from a polyhydric alcohol, polyhydric alcohol ether, polyhydric alcohol ester and ethanol amine and a water-soluble cellulose ether. A gelatinous coolant composition using the gel in which water-containing water-absorbing polymers are dispersed keeps the gel stable in a broad range of temperature, and therefore the coolant composition is excellent in flexibility to a low temperature and form retentivity, which are required for coolants, and provides long cooling effect.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention is
Regarding a gel of polyhydric alcohol and its derivative or ethanolamines that can be handled as a solid, further, cold storage in the medical field, cold storage of food, cold storage composition used for storage, particularly wide temperature range (- The present invention also relates to a gel-like ice pack composition having flexibility even at around 30 ° C. to 80 ° C.) and a method for producing the same.

[0002]

2. Description of the Related Art Polyhydric alcohols and their derivatives and ethanolamines have no polymer dissolved therein, and it is difficult to maintain high viscosity. Therefore, it has been practiced to produce and dissolve these polymers, or to dissolve the polymers at a high concentration to form a gel.

In particular, polyhydric alcohols generally have high boiling points, low transdermal absorbability, and low toxicity, and therefore are often used for medicinal purposes. They are impregnated with poultices for bruises, sprains, and bone fractures. , Is used as a poultice. Also,
Oral drugs and suppositories are often impregnated with drugs, and are often used as solvent solutions for drugs to control drug release. To obtain the viscoelasticity required for these drugs, the special polymer described above is used. It is generally practiced to add a large amount or use a polymer instead. However, if a large amount of these polymers is used, the compatibility with the drug deteriorates,
In some cases, impregnation of the drug becomes difficult.

This polymer is used not only for medicinal purposes but also for trace amounts of it added to agricultural chemicals and foods to maintain caking properties and water retention, but it is used in a state of higher viscoelasticity. However, when it is used for improving the texture of edible noodles, for example, there is a problem that a large amount of polymer is added.

Further, the polyhydric alcohol derivative may be used as a surfactant, but all of them can be used only in a liquid state and cannot be used in a solidified state. was there.

On the other hand, a water-soluble polymer having a viscosity such as agar or polyvinyl alcohol is dissolved in water as a cooling agent for cold storage in the medical field such as ice sac and ice pillow, cold storage of foods, etc. Then, those prepared in gel form have been used. However, such a cooling agent has a phenomenon that when cooled in a general household freezer, it solidifies and loses flexibility. Further, in recent years, a more effective cooling action has been demanded for a cold-preserving agent by improving not only its cooling effect but also its compatibility (fitness) with a human body and a target object. Therefore, various attempts have been made to provide the cold-retaining agent composition with low-temperature flexibility and a function of increasing the cold-retaining ability. For example, JP-B-59-35944 discloses that a water-soluble polymer such as carboxymethyl cellulose is used as a main raw material, and a surfactant such as glycerin fatty acid ester is added to the main raw material.
A gel containing a freezing point curing agent, in JP-A-6-17037, a combination of colloidal silica and water-soluble cellulose ether, and in JP-A-8-325563, a water-soluble polyether polyurethane is prepared. Hydrogel containing sodium chloride and sodium chloride, and JP-A-11-
In 80716, a cold insulator composition etc. in which a specific copolymer crosslinked product is prepared and used as a liquid retention agent and mixed with a salt-containing alcohol aqueous solution to form a gel are reported.

However, these improved ice packs can retain their flexibility even in a considerably low temperature range such as a freezer of a general household, but on the other hand, the cooling effect tends to become short. In addition, depending on the type and concentration of the polymer used, the fluidity such as the original viscosity of the polymer is lost and it becomes a hard gel, and its flexibility changes significantly before and after cooling, which makes it suitable for the human body and objects. There was also the problem that the sex was not sufficient.

On the other hand, Japanese Patent Publication No. 51-38105
As proposed in Japanese Patent Publication, an ice-cold solution is prepared as an antifreeze solution, and a cold-retaining agent composition obtained by adding salt thereto maintains flexibility even at a considerably low temperature, but has a liquid form. Therefore, there is a possibility that the contents may be unevenly distributed in the container or the liquid may be scattered when the contents are damaged.

The present invention has been made in view of the above circumstances, and is a temperature range in which the water-soluble cellulose ether is actually used by mixing a water-soluble cellulose ether with a polyhydric alcohol having a high boiling point and its derivative or ethanolamines. It is an object of the present invention to provide a novel gel which can be handled as a solid at room temperature of 30 ° C. and can be mixed with water or other solvent like a solution. Further, the present invention retains low-temperature flexibility as a cold-retaining agent, and has an excellent cooling effect, and has sufficient compatibility with human bodies and foods,
It is another object of the present invention to provide a gel-like ice pack composition using the gel that can be used repeatedly and a method for producing the same.

[0010]

Means for Solving the Problems and Modes for Carrying Out the Invention As a result of intensive studies to achieve the above object, the present inventors have found that polyhydric alcohols, polyhydric alcohol ethers, polyhydric alcohol esters, and ethanolamines 1 chosen
One or more solvents and water-soluble cellulose ether are dispersed and mixed at room temperature, and then the boiling point of these solvents is adjusted to 10
By heating to a low temperature of about -30 ° C, the water-soluble cellulose ether is dissolved in the solvent, and by cooling this solution to around room temperature, it has no fluidity.
It was also found that a gel impregnated with the above solvent was obtained in an extremely small amount.

Further, as a result of further studies, the present inventors have mixed a water-containing water-absorbing polymer with a solution prepared by mixing a water-soluble cellulose ether with a solvent such as a polyhydric alcohol and heating and dissolving the mixture, followed by cooling. By using the gel-like cold-retaining agent composition obtained in this way, it has sufficient compatibility with the human body and foods, etc. due to its excellent flexibility and shape-retaining performance even at low temperatures, and has sufficient cooling capacity. It was found that a cold-retaining agent having the above-mentioned property that can be repeatedly used is obtained, and the present invention has been completed.

[0012] In the prior art, water-soluble cellulose ethers are used in some cases, for example, by dissolving them in water to develop viscosity, or by blending them when preparing a composition. There is no disclosure of a method for preparing a cold-preserving agent using a gel obtained by mixing with this, heating and dissolving, and then cooling.

Therefore, the present invention comprises (1) one or more solvents selected from polyhydric alcohols, polyhydric alcohol ethers, polyhydric alcohol esters, and ethanolamines, and a water-soluble cellulose ether. (2) The polyhydric alcohol is ethylene glycol, propylene glycol, diethylene glycol, 1,3-propanediol or glycerin, and (3) the polyhydric alcohol. The ether is ethylene glycol ethyl ether or tripropylene glycol methyl ether, and (4) the gel according to (1), wherein the polyhydric alcohol ester is ethyl glycolate, glyceryl monoacetate or glyceryl diacetate. (1) The gel according to (1), ) Ethanolamines are monoethanolamine or diethanolamine, (1) The gel according to (1), (6) The water-soluble cellulose ether is alkyl cellulose, hydroxyalkyl cellulose or hydroxyalkyl alkyl cellulose. The water-containing water-absorbing polymer is dispersed in the gel according to any one of (1) to (5) and the gel according to any one of (7), (1) to (6). Gel-like ice pack composition, (8) water-soluble cellulose ether, polyhydric alcohol, polyhydric alcohol ether,
The invention is characterized in that it is mixed with one or more solvents selected from polyhydric alcohol esters and ethanolamines and dissolved by heating, and then a water-containing water-absorbing polymer is mixed with this solution and cooled. Provided is a method for producing a gel-like ice pack composition.

The present invention will be described in more detail below.
The solvent used in the present invention is one or more selected from polyhydric alcohols, polyhydric alcohol ethers, polyhydric alcohol esters, and ethanolamines. All of these correspond to those that dissolve the water-soluble cellulose ether by heating. In this case, the polyhydric alcohol preferably has a molecular weight of 300 or less, particularly 150 or less, and the polyhydric alcohol ether is a polyhydric alcohol having 1 to 6 carbon atoms, particularly 1 to 4 carbon atoms.
And monoethers, diethers, and triethers with monohydric aliphatic alcohols, and examples of the polyhydric alcohol ester include monohydric aliphatic carboxylic acids having 1 to 6 carbon atoms, particularly 1 to 4 carbon atoms in the polyhydric alcohol. Examples thereof include monoesters, diesters and triesters. Specifically, as the polyhydric alcohol, for example, ethylene glycol, propylene glycol, diethylene glycol, 1,3-
Examples include propanediol and glycerin. Examples of the polyhydric alcohol ether include ethylene glycol ethyl ether and tripropylene glycol methyl ether. Examples of the polyhydric alcohol ester include ethyl glycolate, glyceryl monoacetate, glyceryl diacetate and the like. Examples of ethanolamines include monoethanolamine,
Diethanolamine and the like can be mentioned.

The water-soluble cellulose ether of the present invention is not particularly limited, and any cellulose ether which becomes water-soluble by etherifying cellulose can be used. Among these, alkyl cellulose, hydroxyalkyl cellulose, and hydroxyalkylalkyl cellulose are preferable. Among these, methyl cellulose (MC), hydroxypropyl methyl cellulose (HPMC), hydroxyethyl methyl cellulose (HEMC), hydroxyethyl ethyl cellulose (HEEC), hydroxypropyl cellulose (HP
C) and hydroxyethyl cellulose (HEC) are preferable, and specifically, in order to impart water solubility to the cellulose, alkyl cellulose such as water-soluble methyl cellulose (MC) having a methoxyl group of 10 to 40% by weight and a hydroxypropoxyl group of 40% by weight. ~ 70% by weight of hydroxypropyl cellulose (HPC), hydroxyethoxyl group of 30 ~
Hydroxyalkyl cellulose such as 70% by weight of hydroxyethyl cellulose (HEC), 10 to 40% by weight of methoxyl group, and 3 to 30% by weight of hydroxyalkyl group for improving solubility, hydroxypropylmethylcellulose (HPMC) or hydroxyethylmethylcellulose. (HEMC), and hydroxyalkylalkyl cellulose such as hydroxyethylethyl cellulose (HEEC) having 5 to 20% by weight of ethoxyl groups and 10 to 45% by weight of hydroxyethoxyl groups.

The degree of substitution of these is determined by J. G. Gobl
er, E.E. P. Samsel, and G.M. H. Bea
ber, Talanta, 9, 474 (1962) and can be measured according to the method by Zeisel-GC.

Further, the water-soluble cellulose ether of the present invention preferably has a high weight average molecular weight in order to obtain hardness in a gel state. As a value corresponding to the index of the molecular weight of cellulose ether, JIS K 2283-1993 is used.
In the Ubbelohde viscometer specified in 1., a cellulose ether having a measured viscosity value of a 2 wt% aqueous solution at 20 ° C. of 3 mPa · s or more, preferably 100 mPa · s or more is desirable. The upper limit is 300,000 mP
It is preferably a · s or less.

In the present invention, the concentration of the water-soluble cellulose ether in the above solvent exceeds 10% by weight,
If it can be dissolved by heating and a gel can be formed by cooling, there is no particular problem, but it is desirable that the gel is formed with a low concentration of cellulose ether as the purpose of the present invention. The concentration is 10% by weight or less, preferably 0.1
˜5 wt%, more preferably 0.2 to 3 wt%.

In the novel gel of the present invention, the above-mentioned solvent and water-soluble cellulose ether are dispersed and mixed at room temperature and then heated to bring the water-soluble cellulose ether into a state of being dissolved in the solvent. It can be obtained by cooling to (0 to 30 ° C.).

In the present invention, the temperature for heating to dissolve the water-soluble cellulose ether in the solvent needs to be lower than the boiling point of the solvent used, and this temperature is the kind of the solvent and the water-soluble cellulose ether used. It depends on the boiling point of the solvent used.
It is preferable to dissolve in a temperature range as low as about -30 ° C.

Here, it is possible to add an additive to the gel obtained in the present invention to such an extent that the gel formation is not hindered during cooling after heating and dissolution. As the additive, those containing as little water as possible are preferable, for example, pigments and dyes such as carbon, inorganic materials such as cements and alumina, alumina hydroxide, inorganic hydroxides such as magnesium hydroxide, bentonite, talc and kaolin. Clay materials such as, and organic substances such as carbon that are difficult to melt at the heating temperature. Further, an organic substance having a melting point at a relatively low temperature, such as a fragrance, can be added during cooling for forming a gel to be used as a fragrance.

The gel obtained as described above is characterized in that it can return to a solution when heated again in the temperature range in which it melts. Also, this gel is 0-30
It can be handled as a solid at room temperature at 0 ° C., and can be mixed with water and other solvents like a solution.

The gel-like cold insulating composition of the present invention obtained by using the above-mentioned gel is used in one or more solvents selected from polyhydric alcohols, polyhydric alcohol ethers, polyhydric alcohol esters, and ethanolamines. , 10 to 30 from the boiling point of the solvent after dispersing the water-soluble cellulose ether
It is obtained by heating to a temperature as low as ℃ to dissolve it, and by mixing this solution with a water-containing water-absorbing polymer and cooling, the gel-like cold insulating composition has a low temperature (-30
Hold the gel state from ℃) to high temperature (around 80 ℃),
It has excellent flexibility and shape retention performance. Therefore,
In the range of actual use, the cooling agent is excellent in cooling effect and does not lose flexibility, so that it is possible to obtain a cold-retaining agent having good compatibility with a human body and an object and having good cold-retaining efficiency.

Since such a cooling agent composition contains a water-containing water-absorbing polymer, not only can the heat of melting of ice be utilized, but also a gel of water-soluble cellulose ether and polyhydric alcohol can provide an effect of softening the temperature change. . Also,
As a structure, since the water-containing water-absorbing polymer is dispersed in a continuous gel body, the gel does not lose its original flexibility.

The cellulose ether used in the gel-like cold insulating composition of the present invention is not particularly limited, and the above-mentioned cellulose ether can be used.

As the solvent used in the gel-like cold insulating composition of the present invention, those mentioned above can be used. Among them, polyhydric alcohols are preferable, and the composition is suitable for humans and foods. When applied, it is desirable to use propylene glycol, ethylene glycol, glycerin or the like in consideration of safety.

The concentration of these water-soluble cellulose ethers in the above solvent is not particularly limited as long as a gel is formed when heated and dissolved, but a solution immediately after the water-soluble cellulose ether is dissolved in the above solvent. Since it is desired that the following water-containing water-absorbent polymers are uniformly mixed and form a uniform gel after cooling, the concentration thereof is preferably 0.05 to 10% by weight, particularly 1 to
5% by weight is preferred.

The water-containing water-absorbent polymer used in the present invention is
A water-absorbing polymer exemplified below is impregnated with water. Examples of the water-absorbing polymer include polyacrylic acid-based water-absorbing polymer, polyvinyl alcohol-based water-absorbing polymer, polyacrylamide-based water-absorbing polymer, polyoxyethylene-based water-absorbing polymer, starch-based graft polymer, and carboxymethylated starch polymer. Water-absorbing polymers of starch, cellulose-acrylonitrile graft polymers, cellulose-based graft polymers such as regenerated cellulose / Na polyacrylate graft polymers, and carboxymethyl cellulose-based water-absorbing polymers And the like. Further, the water-absorbent polymer may be replaced with clay mineral such as bentonite or porous silica powder as long as the water-absorbent and water-retaining ability can be obtained.

The amount of water impregnated in the water-absorbing polymer is within the range of the water-absorbing ability of the water-absorbing polymer.
There is no particular limitation as long as water separation does not occur. However, the larger the amount of water impregnated in the water-absorbent polymer, the higher the capacity as a cold-retaining agent, but the higher the proportion of water frozen during cooling and the more it solidifies, so adjustment is necessary. In the present invention, the amount of water impregnated in the water-absorbent polymer varies depending on the type of the water-absorbent polymer, but is approximately 1 to 10 parts by weight with respect to 1 part by weight of the water-absorbent polymer.
It is preferably set to 00 parts by weight, particularly 3 to 300 parts by weight.

The mixing ratio of the solution in which the water-soluble cellulose ether is dissolved in the solvent and the water-absorbing water-absorbing polymer is 10 to 99 parts by weight of the solution in which the water-soluble cellulose ether is dissolved in the solvent, preferably Is 50 ~
It is desirable that the water-containing water-absorbent polymer is 1 to 90 parts by weight, preferably 1 to 50 parts by weight, based on 99 parts by weight. A gel containing only a water-soluble cellulose ether and the above solvent has excellent flexibility, but there is a possibility that the cooling effect of ice may not be obtained, and if the content of the water-absorbing water-absorbing polymer is too large, the cooling property is increased. , The composition freezes,
May solidify and lose flexibility.

It is possible to add components other than the above-mentioned components to the gel-like cold insulating composition of the present invention within a range not impairing the object of the present invention.

As a method for preparing the gel-like cold insulating composition of the present invention, the above-mentioned water-soluble cellulose ether is used as a solvent selected from polyhydric alcohols, polyhydric alcohol ethers, polyhydric alcohol esters, and ethanolamines, or these solvents. After mixing and dispersing in a mixed solvent, the boiling point of the solvent should be 1
In a solution that has been dissolved by heating to a temperature as low as 0 to 30 ° C,
A gel-like composition can be obtained by mixing the water-containing water-absorbing polymer before the gelation of this solution and cooling.

The ice pack composition of the present invention comprises polyethylene,
By filling an appropriate amount in a flexible container made of synthetic resin such as polyvinyl chloride or rubber, it can be used as a cooler. Furthermore, by covering with non-woven fabric,
Although it is possible to improve the feel of the contact surface, the shape and material of the container are not limited in the present invention as long as it is a container capable of containing the cold insulating composition without leaking.

[0034]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Examples 1 to 17] As shown in Table 1 below, 100 g of a solvent was mixed with cellulose ether in a 200 ml beaker to a predetermined concentration and heated to a predetermined temperature. After the solution was dissolved, it was cooled to the gel forming temperature and a 10 yen coin was placed on the formed gel to evaluate whether or not it settled.

[0036]

[Table 1]

HPMC: hydroxypropylmethylcellulose, manufactured by Shin-Etsu Chemical Co., Ltd. HEMC: hydroxyethylmethylcellulose, manufactured by Shin-Etsu Chemical Co., Ltd. MC: methylcellulose, manufactured by Shin-Etsu Chemical Co., Ltd. HPC: hydroxypropyl cellulose, Nippon Soda Co., Ltd. ) HEC: hydroxyethyl cellulose, Aqualon Co., Ltd. HEEC: hydroxyethyl ethyl cellulose, manufactured by Velor Novel

[Examples 18 to 25] Water-soluble cellulose ethers of the types and blending amounts shown in Table 2 and propylene glycol were mixed at room temperature and then heated and dissolved, and water in the proportions shown in Table 2 was added. The impregnated water-absorbent polymer and bentonite were mixed and uniformly stirred to obtain a cold insulating composition. 100 g of the obtained cold insulating composition was added to a bag-shaped container (10 mm × 15 mm) made of a polyethylene resin film having a thickness of 0.5 mm.
And the mouth was closed to prepare a cold insulating agent.

[Comparative Examples 1 and 2] The water-absorbent polymer shown in Table 2, water and propylene glycol were mixed and filled in the same container as in Example to prepare a cold insulating agent.

[Comparative Example 3] With the types and blending amounts shown in Table 2, water-soluble cellulose ether was dispersed in water heated to 90 ° C, cooled in a cooling layer at 5 ° C, and dissolved in an aqueous solution to absorb water. A water-soluble polymer and propylene glycol,
A container similar to that used in the example was filled to prepare a cooling agent.

HPMC in Table 2 is hydroxypropylmethyl cellulose (Metronose 60SH-4000 manufactured by Shin-Etsu Chemical Co., Ltd.), and MC is methyl cellulose (Metroze SM-400 manufactured by Shin-Etsu Chemical Co., Ltd.).
0), PG was propylene glycol, a water absorbent polymer was an acrylic acid water absorbent polymer (Diawet manufactured by Mitsubishi Petrochemical Co., Ltd.), bentonite was Kunimine Industry Co., Ltd. Kunibond, and pure water was used as water.

The cooling agents of the above Examples and Comparative Examples were evaluated for their cooling effect, low temperature flexibility and shape retention by the methods described below.

Cooling effect: Each of the obtained cold insulating agents was placed at -16 ° C.
In a domestic freezer for 24 hours. The cooled cold-retaining agent was allowed to stand still on a test tube stand installed in a thermostatic chamber at 25 ° C., and the time until the central portion of the cold-retaining agent reached 25 ° C. was measured. The measurement results are as shown in Table 3, which shows that the one having a long time is excellent in the cold insulating effect.

Low temperature flexibility: After each cold storage agent was left standing in a domestic freezer at -16 ° C. for 24 hours, the softness when the cold storage agent was pushed by hand was judged. The results are shown in Table 3, where “○” means that the sample is in a soft state, “Flexible” when the other part is hard or liquid although it is partially flexible, and “x” when it is not hard and not deformed. It was

Shape-retaining property: Each cold-retaining agent was allowed to stand in a domestic freezer at -16 ° C. for 24 hours, and then the cold-retaining agent was bent so that there was no change or slight change in the shape. When the deformation returns with time, it is judged as "○", when it can be bent but the deformation does not return, it is judged as "△", when it is too hard to be bent, or as liquid, it is judged as "×". The results are shown in Table 3. Regarding the shape retention, the shape retention of the cooling agent left at room temperature for 8 hours and the shape retention of the cooling agent left at 45 ° C. for 8 hours were determined in the same manner as above, and Table 3 shows the results. Indicated.

[0046]

[Table 2]

[0047]

[Table 3]

[0048]

According to the present invention, a polyhydric alcohol having a high boiling point, its derivative and ethanolamine are mixed with a water-soluble cellulose ether to obtain a solid at room temperature of 0 to 30 ° C. which is actually used. It is possible to obtain a gel that can be handled as a substance and can be mixed with water or other solvent as well as a solution. In addition, the gel-like cold insulating composition of the present invention using this gel has a stable gel state in a wide temperature range (around -30 ° C to 80 ° C), and therefore has low temperature flexibility and shape retention as a cold insulating agent. Excellent performance and long-term cooling effect.

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Claims (8)

[Claims] 1. A gel comprising a water-soluble cellulose ether and one or more solvents selected from polyhydric alcohols, polyhydric alcohol ethers, polyhydric alcohol esters, and ethanolamines. 2. The polyhydric alcohol is ethylene glycol, propylene glycol, diethylene glycol,
The gel according to claim 1, which is 1,3-propanediol or glycerin. 3. The gel according to claim 1, wherein the polyhydric alcohol ether is ethylene glycol ethyl ether or tripropylene glycol methyl ether. 4. The gel according to claim 1, wherein the polyhydric alcohol ester is ethyl glycolate, glyceryl monoacetate or glyceryl diacetate. 5. The gel according to claim 1, wherein the ethanolamines are monoethanolamine or diethanolamine. 6. The gel according to claim 1, wherein the water-soluble cellulose ether is alkyl cellulose, hydroxyalkyl cellulose or hydroxyalkylalkyl cellulose. 7. A gel-like cold insulating composition comprising the gel according to claim 1 and a water-containing water-absorbing polymer dispersed therein. 8. A water-soluble cellulose ether is dissolved by mixing with one or more solvents selected from polyhydric alcohols, polyhydric alcohol ethers, polyhydric alcohol esters, and ethanolamines and heating. rear,
A method for producing a gel-like cold insulating composition, which comprises mixing a water-containing water-absorbing polymer with this solution and cooling.