JP6750968B2 - Hydrous gel composition - Google Patents

Description

The present invention relates to a hydrogel composition.

2. Description of the Related Art Conventionally, patches and poultices having desired effects have been produced by gels using various polymer compounds as gel bases. Among such polymer compounds, carboxymethylcellulose or a salt thereof is often used for such various agents because it can achieve a high water content.

For example, in Patent Document 1, an aqueous pressure-sensitive adhesive base containing a water-soluble polymer substance such as polyacrylic acid and/or a salt thereof, carboxymethyl cellulose or a salt thereof, a metal crosslinking agent such as an aluminum compound, and glycine A pressure-sensitive adhesive composition containing an amino acid or the like is disclosed, and after the pressure-sensitive adhesive composition is applied to a support, appropriate pressure-sensitive adhesiveness and adhesiveness are exhibited. Patent Document 2 discloses a poultice obtained by mixing an anionic water-soluble polymer such as carboxymethyl cellulose or a salt thereof, an inorganic salt such as a water-soluble aluminum salt, and an organic acid or an inorganic acid. It has been disclosed and enhances shape retention and water retention.

Further, Patent Document 3 discloses an aqueous gel composed of an aqueous solution of an anionic water-soluble polymer such as carboxymethyl cellulose or a salt thereof, a cross-linking agent such as an aluminum compound, and microfibrous cellulose, which is electrostatically charged. Acid compounds such as succinic anhydride and lactic acid are also used in order to cause cross-linking due to such interaction to promote gelation. Such an aqueous gel improves the gel strength and makes the gel uniform by the above-mentioned specific cellulose.

JP, 10-265373, A JP, 11-116468, A JP, 2003-277637, A

In such a gel, if its water content is increased, it brings a fresh feel to the use scene, has excellent followability to the skin, and can provide a comfortable feeling of use, and therefore carboxymethylcellulose or a salt thereof is more preferable as a gel base. Although it is effective to use in a large amount, it is difficult to secure the stability of the gel for a long time as the water content increases, so further improvement is desired.

However, in the above-mentioned Patent Document 1, focusing solely on the development of adhesiveness and adhesiveness, in order to increase the stability of the gel while increasing the amount of carboxymethyl cellulose or a salt thereof, detailed studies are still required. There is a need. Further, even if gelation is started or progressed by succinic acid, lactic acid, fumaric acid, or the like adopted in the techniques described in Patent Documents 2 to 3, it is difficult to secure high gel stability over time. In particular, as a neutralizing agent when using carboxymethyl cellulose or a salt thereof, if succinic acid, which has been frequently used, is added, the gel becomes destabilized over time in a storage environment at high temperature. Was also found. Therefore, when exposed to a harsh storage environment for a long time, there is a possibility that the gel strength may be reduced or the liquid may be separated from the gel.

Therefore, the present invention relates to a water-containing gel composition which has high gel stability over a long period of time while maintaining a high water content and is capable of sufficiently suppressing deterioration of gel strength and separation of liquid from gel. ..

Therefore, the present inventor has conducted various studies, using an anionic water-soluble polymer compound containing a large amount of carboxymethyl cellulose or a salt thereof, while increasing the content of water, a neutralizing acid containing a specific carboxyl group-containing compound. It has been found that a water-containing gel composition capable of ensuring high gel stability over time can be obtained by containing the polyvalent metal compound and

That is, the present invention provides the following components (A), (B), (C), and (D):
(A) Anionic water-soluble polymer compound containing 75% by mass or more of carboxymethyl cellulose or a salt thereof,
(B) a neutralizing acid containing one or more carboxyl group-containing compounds (b1) selected from L-glutamic acid, acetic acid, dimethylhydroxypropionic acid, and nicotinic acid;
It relates to a hydrous gel composition containing (C) a polyvalent metal compound and (D) water in an amount of 60% by mass or more and 95% by mass or less.

According to the hydrogel composition of the present invention, while maintaining a high water content, it is possible to sufficiently secure the gel stability over time, so that even under a severe storage environment for a long time, the gel strength is high. And the separation of the liquid from the gel can be effectively suppressed.

Hereinafter, the present invention will be described in detail.
The hydrogel composition of the present invention contains, as the component (A), an anionic water-soluble polymer compound containing carboxymethyl cellulose or a salt thereof in an amount of 75% by mass or more. By using such an anionic water-soluble polymer compound, the carboxyl group of carboxymethyl cellulose or a salt thereof and the polyvalent metal compound of the component (C) described below which acts as a cross-linking agent form ionic crosslinks, which is high. A gel with water retention and good gel strength can be constructed. In the present invention, the “water-soluble polymer compound” refers to a compound which, when dispersed in water, uniformly dissolves to give viscosity.

Examples of the salt of carboxymethyl cellulose include one or more selected from alkali metal salts such as sodium salt and potassium salt, and ammonium salt. From the viewpoint of favorably forming ionic crosslinks, and cost and availability. From the viewpoint of, carboxymethyl cellulose sodium is preferable. In addition, the degree of etherification of carboxymethyl cellulose or a salt thereof is preferably 0.6 to 1.1 from the viewpoint of maintaining appropriate gel strength to enhance the ability to follow the skin and ensuring the stability of the gel. And more preferably 0.65 to 0.9.

The degree of etherification means the degree of substitution of the carboxymethyl group per glucose unit. The degree of etherification can be obtained, for example, according to the CMC Industry Association analysis method (ashing method). 1 g of sodium carboxymethylcellulose is precisely weighed, put in a magnetic crucible and ashed at 600° C., and sodium oxide produced by ashing is titrated with phenolphthalein with N/10 sulfuric acid as an indicator, and titration amount per 1 g of sodium carboxymethylcellulose YmL can be put into the following formula to calculate and show the obtained degree of etherification.
Degree of etherification=(162×Y)/(10,000-80×Y)

Carboxymethyl cellulose or a salt thereof has a viscosity at 25° C. when made into a 1% by mass aqueous solution, from the viewpoint of maintaining an appropriate gel strength while ensuring conformability to the skin, and the viewpoint of ensuring gel stability over time. Is preferably 1,500 to 10,000 mPa·s, more preferably 2,500 to 8,000 mPa·s, as measured by a B-type viscometer.

The content of carboxymethyl cellulose or a salt thereof is preferably 75% by mass or more in the anionic water-soluble polymer compound of the component (A), from the viewpoint of having both good usability and high gel stability. Is 80% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and preferably 100% by mass or less.

Anionic water-soluble polymer compounds other than carboxymethyl cellulose or salts thereof that can be contained in the anionic water-soluble polymer compound of component (A) have polar groups present in the molecule only as anionic functional groups. Examples of the compound include, for example, poly(meth)acrylic acid or a salt thereof, polystyrene sulfonic acid or a salt thereof, polyisoprene sulfonic acid or a salt thereof, polyvinyl naphthalene sulfonic acid or a salt thereof, polyvinyl. Examples thereof include sulfonic acid or a salt thereof, poly(meth)acrylamide dimethylpropane sulfonic acid or a salt thereof, poly(meth)acryloyloxyethyl sulfonic acid or a salt thereof, alginic acid or a salt thereof, and an anionic starch derivative.

The content of the component (A) is from the viewpoint that the carboxyl group contained in carboxymethyl cellulose or a salt thereof and the polyvalent metal compound of the component (C) described later satisfactorily form ionic crosslinks to construct a gel. In the water-containing gel composition, the content is preferably 2.2% by mass or more, more preferably 2.7% by mass or more, and further preferably 3% by mass or more. Further, the content of the component (A) is preferably 6% by mass or less, more preferably in the hydrogel composition of the present invention, from the viewpoint of imparting appropriate flexibility and conformability to skin to the gel. Is 5% by mass or less, and more preferably 4% by mass or less. And the content of the component (A) in the hydrogel composition of the present invention is preferably 2.2 to 6% by mass, more preferably 2.7 to 5% by mass, and further preferably 3%. ~ 4% by mass.

The hydrogel composition of the present invention comprises, as the component (B), one or more carboxyl group-containing compounds (b1) selected from L-glutamic acid, acetic acid, dimethylhydroxypropionic acid, and nicotinic acid. Contains an acid. The neutralizing acid acts as a so-called cross-linking agent in increasing the content of carboxymethylcellulose or a salt thereof in the above component (A) in order to achieve a high water content like the hydrogel composition of the present invention. It is an acid compound used in combination to release polyvalent metal ions from the component (C) described below. It has been found by the present inventor that succinic acid, lactic acid, fumaric acid or the like which has been frequently used as the neutralizing acid can be used to destabilize the released polyvalent metal ion. Then, the present inventor unexpectedly greatly improves the gel stability over time during storage at high temperature by using the neutralizing acid of the component (B) containing the carboxyl group-containing compound (b1). We have found that we can contribute.

Among the above components (b1), L-glutamic acid is preferable from the viewpoint of effectively enhancing the gel stability over time. The content of the L-glutamic acid in the component (B) is preferably 20% by mass or more, and more preferably from the viewpoint of effectively suppressing the decrease in gel strength and the separation of the liquid from the gel over a long period of time. Is 50% by mass or more, more preferably 70% by mass or more, and preferably 100% by mass or less.

The component (B) can further contain other carboxyl group-containing compound (b2) other than the component (b1) as a neutralizing acid. That is, in the hydrogel composition of the present invention, the component (b1) may be used alone as the neutralizing acid for the component (B), or the component (b2) may be used in combination. ..
Examples of the component (b2) include organic acids having 1 to 3 carboxyl groups in the molecule, or amino acids. Specifically, for example, glycolic acid, lactic acid, and the like have 1 carboxyl group in the molecule. Organic acids: Organics with two carboxyl groups in the molecule, such as oxalic acid, malonic acid, maleic acid, fumaric acid, succinic acid, methylmalonic acid, glutaric acid, adipic acid, pimelic acid, phthalic acid, tartaric acid, malic acid Acids; organic acids having three carboxyl groups in the molecule such as citric acid and propanetricarboxylic acid; amino acids such as glycine, L-aspartic acid and tranexamic acid. Among the above components (b2), maleic acid, fumaric acid, succinic acid, glutaric acid, in combination with the above component (b1), from the viewpoint of more effectively suppressing the decrease in gel strength and the separation of the liquid from the gel, One or more selected from adipic acid, phthalic acid, and L-aspartic acid is preferable, and one or more selected from fumaric acid, succinic acid, glutaric acid, and adipic acid is more preferable.

The content of the component (B) is preferably 0.1% by mass or more in the hydrous gel composition of the present invention, from the viewpoint of more effectively suppressing the decrease in gel strength and the separation of the liquid from the gel. , More preferably 0.2 mass% or more, still more preferably 0.3 mass% or more. In addition, the content of the component (B) is preferably 1.2% by mass or less in the hydrogel composition of the present invention from the viewpoint of not inhibiting the construction of a gel by the component (A) and the component (C) described later. And more preferably 1 mass% or less, and further preferably 0.9 mass% or less. The content of the component (B) in the hydrogel composition of the present invention is preferably 0.1 to 1.2% by mass, more preferably 0.2 to 1% by mass, and further preferably Is 0.3 to 0.9 mass %.

The mass ratio ((A)/(B)) between the content of the component (A) and the content of the component (B) is preferably from the viewpoint that the pH does not become too low and the gel construction proceeds well. Is 2 or more, more preferably 2.5 or more, further preferably 3 or more, and still more preferably 4 or more. In addition, the mass ratio ((A)/(B)) of the content of the component (A) and the content of the component (B) is preferably 30 or less from the viewpoint of accelerating the construction of the gel, It is more preferably 18 or less, still more preferably 12 or less, still more preferably 10 or less. The mass ratio ((A)/(B)) between the content of the component (A) and the content of the component (B) is preferably 2 to 30, more preferably 2.5 to 18. , More preferably 3 to 12, and even more preferably 4 to 10.
Furthermore, the number of moles of the carboxyl groups of the component (B) (total carboxyl groups of the component (b1) and the component (b2)) is 1 mol of the carboxymethyl group of the carboxymethyl cellulose or the salt thereof contained in the component (A). It is preferably 0.1 to 0.8 mol, more preferably 0.2 to 0.5 mol.

The hydrogel composition of the present invention contains a polyvalent metal compound as the component (C). The component (C) can form a gel having high water retention and good gel strength by forming ionic cross-links with the carboxyl group contained in the carboxymethyl cellulose or the salt thereof contained in the component (A).

Examples of the component (C) include compounds containing polyvalent metals such as aluminum, magnesium, titanium, chromium, manganese, iron, cobalt, nickel, zinc, cadmium, lead and calcium, or salts thereof. Specifically, for example, polyvalent metal hydroxides such as aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, magnesium aluminum hydroxide; aluminum oxide, calcium oxide, magnesium oxide, zinc oxide, aluminate Polyvalent metal oxides such as sodium; aluminum sulfate, potassium aluminum sulfate, ammonium aluminum sulfate, aluminum carbonate, aluminum nitrate, aluminum chloride, calcium sulfate, calcium carbonate, calcium chloride, magnesium sulfate, magnesium carbonate, magnesium chloride, zinc sulfate, Polyvalent metal inorganic salts such as zinc carbonate, zinc chloride, magnesium (meth)aluminate silicate, synthetic hydrotalcite; aluminum acetate, calcium acetate, magnesium acetate, zinc acetate, aluminum lactate, aluminum stearate, aluminum myristate, Examples thereof include aluminum glycinate, aluminum benzoate, allantoinchlorohydroxyaluminum, and polyvalent metal organic salts such as alkaline earth metal salts of calcium and magnesium of thioglycolic acid. Of these, a compound containing aluminum or a salt thereof is preferable, and aluminum hydroxide or magnesium (meth)aluminum silicate is more preferable, from the viewpoint of easily controlling the reaction rate during crosslinking.

The content of the component (C) in the hydrogel composition of the present invention is preferably 0.01% by mass or more, and more preferably 0. It is at least 05 mass%, more preferably at least 0.1 mass%. In addition, the content of the component (C) is preferably 2% by mass or less in the hydrous gel composition of the present invention, and more preferably from the viewpoint of imparting appropriate flexibility and conformability to skin to the gel. Is 1% by mass or less, more preferably 0.4% by mass or less, still more preferably 0.25% by mass or less. The content of the component (C) in the hydrogel composition of the present invention is preferably 0.01 to 2% by mass, more preferably 0.05 to 1% by mass, and further preferably 0. 0.1 to 0.4% by mass, and more preferably 0.1 to 0.25% by mass.

From the viewpoint that the mass ratio ((A)/(C)) of the component (A) and the component (C) forms an ionic crosslink efficiently, and in combination with the component (B), the reduction of the gel strength is effectively ensured. It is preferably 3 or more, more preferably 10 or more, and further preferably 15 or more. Further, the mass ratio ((A)/(C)) of the component (A) and the component (C) is preferably 100 or less from the viewpoint of maintaining the flexibility of the gel and maintaining good conformability to the skin. And more preferably 50 or less, and further preferably 30 or less. The mass ratio ((A)/(C)) of the component (A) and the component (C) is preferably 3 to 100, more preferably 10 to 50, and further preferably 15 to 30. ..

The hydrogel composition of the present invention contains 60 mass% or more and 90 mass% or less of water as the component (D). As described above, in the hydrous gel composition of the present invention, since the carboxymethyl cellulose or a salt thereof in the component (A) has a high content, the water content is high and the gel stability over time is excellent, While maintaining a fresh feel and appropriate flexibility in the scene, it is possible to effectively suppress deterioration of gel strength and separation of liquid from gel even under a harsh storage environment for a long time, which is excellent for use. It can bring a feeling.

The content of the component (D) in the hydrogel composition of the present invention is 60% by mass or more, preferably 65% by mass or more, and more preferably 70% from the viewpoint of imparting an excellent feeling of use. It is at least mass%, more preferably at least 75 mass%. Further, the content of the component (A) is 95% by mass or less, preferably 92% by mass or less, and more preferably in the hydrogel composition of the present invention, from the viewpoint of ensuring gel stability. Is 90% by mass or less, and more preferably 85% by mass or less. And content of a component (D) is 60 mass% or more and 95 mass% or less in the water-containing gel composition of this invention, Preferably it is 65-92 mass %, More preferably, it is 70-90 mass. %, and more preferably 75 to 85 mass %.

The hydrogel composition of the present invention includes, in addition to the above-mentioned components, other components usually used in cosmetics and pharmaceuticals, for example, polyvinyl alcohol, polyvinylpyrrolidone, nonionic water-soluble polymer compounds such as hydroxyethyl cellulose; glycerin and the like. In addition to humectants, oils, surfactants, medicinal ingredients, preservatives, antioxidants, ultraviolet absorbers, solubilizers, colorants, cooling agents, warming agents, fragrances and the like may be appropriately contained.

In order to produce the hydrogel composition of the present invention, for example, the above components (B) and (D) are first mixed to uniformly dissolve the component (B), and then the other components and other necessary Accordingly, other components are mixed, dissolved or dispersed, and added to the mixed liquid of the component (B) and the component (D). Next, this is stirred to prepare an uncrosslinked gel stock solution, and the uncrosslinked gel stock solution applied to a peelable film is sandwiched and spread using a Baker applicator or the like. Then, the hydrogel composition of the present invention is obtained by aging at room temperature or under heating for several days.

Furthermore, the hydrogel composition of the present invention can be formed into a layer and used as a gel layer, and a base material layer such as a nonwoven fabric or a release layer such as a film can be laminated to prepare a patch. Examples of such a laminating method include a method in which one or both surfaces sandwiching the above-mentioned gel stock solution is used as a base material layer or a release layer, or after a gel layer made of a hydrous gel composition is once prepared, a base material layer or a release layer is then formed. Examples include a method of pressing and stacking on such a layer.

From the viewpoint of handleability, the hydrogel composition of the present invention is preferably used by laminating it on a base material layer such as a non-woven fabric, a woven fabric, a knitted fabric, or paper, and more preferably by laminating it on a non-woven fabric. preferable. In a conventional hydrogel composition, when laminated on a base material layer, it is usual to use a hydrophobic material as a material forming the base material layer from the viewpoint of suppressing exudation of the liquid separated from the gel. However, the hydrogel composition of the present invention effectively suppresses the separation of the liquid from the gel for a long time even if a hydrophilic material is used as the base material layer, and exudes the liquid to the base material layer. Can be prevented. Therefore, it is possible to select any material of the base material layer according to the purpose. For example, when the water-containing gel composition of the present invention is used as a cooling patch sheet, it is preferable to use a nonwoven fabric containing hydrophilic fibers as the base material layer to be laminated from the viewpoint of improving the cooling effect.

Materials for the hydrophilic fiber include rayon, cotton, cupra, hemp, wool, silk, acetate, cellulose, wood pulp, non-wood pulp, etc.; hydroxyl group, carboxyl group, sulfonic acid group, amide group, amino acid group. A polymer having a hydrophilic group such as polyvinyl alcohol, polyethylene glycol, cellulose acetate, polyacrylamide, melamine resin, nylon, a fiber made of a hydrophilic polymer such as hydrophilic polyurethane; hydrophilized polyester, etc. A fiber made of a hydrophobic polymer; a composite fiber having a hydrophobic portion and a hydrophilic portion made of a hydrophobic polymer such as polyethylene or polypropylene can be used.

The water-containing gel composition of the present invention is preferably used, for example, by forming a gel layer as described above to prepare a patch, and sticking the surface of the gel layer to the skin for use, since it has a high water content. Since it brings a fresh feel to the skin at times and is excellent in gel stability over time, it can be used while maintaining a comfortable feeling for a long time even under a severe storage environment. Therefore, the hydrogel composition of the present invention has a wide variety of uses as cosmetics, pharmaceuticals, quasi-drugs and miscellaneous goods to be applied to the outer skin (including the scalp), and is applied onto the skin at a desired site. And can be used comfortably.

Hereinafter, the present invention will be specifically described based on Examples. Unless otherwise indicated in the table, the content of each component is% by mass.

[Examples 1 to 4, Comparative Examples 1 to 11]
According to the formulation shown in Table 1, a patch containing the hydrogel composition was prepared by the following method.
Specifically, first, purified water and neutralized acid were put into a universal mixing stirrer (5DMV-rr, manufactured by Dalton Co., Ltd.), and mixed and dissolved for 5 minutes. Next, a mixed solution of propylene glycol in which glycerin and methyl paraoxybenzoate were dissolved by heating, sodium carboxymethyl cellulose, and dry aluminum hydroxide gel was put into a stirrer, and the gauge pressure was reduced to a pressure of -0.095 MPa. In this state, high speed stirring was carried out for 0.5 hours, the stirring was stopped and the pressure was returned to normal pressure to prepare an uncrosslinked gel stock solution.

Then, the resulting uncrosslinked gel stock solution is sandwiched between a siliconized surface of a polypropylene (PP) film having one surface treated with silicon and a polyethylene terephthalate (PET) film, and the gel stock solution has a thickness of 0.8 mm by a baker type applicator. Adjusted to and spread. Then, the PP film was peeled off, and a nonwoven fabric (PET: pulp = 80% by mass: 20% by mass, basis weight = 20 g/m ² , air-laid thickness: 0.22 mm) was attached to the spread gel layer on the gel layer. , A sheet-shaped patch. The obtained patch was sealed in an aluminum pillow and hermetically sealed, and then aged at 50° C. for 2 days to promote a crosslinking reaction in an uncrosslinked gel stock solution to form a gel. When a gel was not formed by aging for 2 days, the necessary number of days was taken until the gel was formed.
Each evaluation was performed using the obtained gel according to the following methods.
The results are shown in Table 1.

<<Evaluation during gel formation>>
The gel strength immediately after formation was sensory evaluated according to the following criteria.
In Comparative Examples 8 to 11, it was not possible to complete the gel formation, and other evaluations could not be performed.
-Gel strength After peeling off the PET film, place it on the table with the gel side up.
The gel portion was observed by pressing the gel portion with a thumb from above.
AA: The gel does not deform even if pressed strongly. A: The gel deforms when pressed hard, but the gel does not collapse. B: The gel collapses when pressed continuously, but there is no problem in using as a body patch C: When pressed, the gel easily crushes, causing problems when used as a body patch.

<<Evaluation when storing gel>>
The patch having the gel layer after crosslinking was die-cut to obtain a test piece (50 mm x 100 mm). The obtained test piece was stored at 50° C. for 1 month, and the gel strength after storage was evaluated in the same manner according to the above criteria, and the gel stability was evaluated according to the following criteria.
・Gel stability AA: Gel strength during gel storage is higher than during gel formation A: Gel strength during gel storage is similar to that during gel storage B: Gel strength during gel storage is lower than during gel formation

According to the results of Table 1, Examples 1 to 4 in which the component (b1) is a neutralizing acid show good stability while maintaining good gel strength from the time of gel formation to after storage. I understand. On the other hand, Comparative Examples 1 to 11 in which only the component (b2) was used alone as the neutralizing acid had inferior results to those of the above Examples 1 to 4, but among them, maleic acid, fumaric acid, It can also be seen that Comparative Examples 1 to 7 using succinic acid, glutaric acid, adipic acid, phthalic acid, and L-aspartic acid show slightly good results.

[Examples 5 to 6, Comparative Examples 12 to 13]
According to the formulation shown in Table 2, first, purified water and polyvinyl alcohol were mixed and stirred at 60° C. with a propeller to dissolve them. After returning to room temperature, a neutralizing acid was added and the propeller was stirred to dissolve it, and then transferred to a universal mixing stirrer (5DMV-rr, Dalton Co., Ltd.). Then, in the same manner as in Example 1, the liquid mixture of the remaining components was additionally charged into a stirrer and stirred under reduced pressure and at high speed to prepare an uncrosslinked gel stock solution.

Then, in the same manner as in Example 1, the obtained uncrosslinked gel stock solution is used to form a patch in the form of a sheet, and aged at room temperature for 1 week to allow the crosslinking reaction in the uncrosslinked gel stock solution to proceed to form a gel. After that, the patch having the crosslinked gel layer was die-cut to obtain a test piece (180 mm×250 mm). The obtained test piece was stored at 50° C. for 2 months, the gel strength after storage was evaluated in the same manner according to the above criteria, and the amount of bleeding into the nonwoven fabric was measured according to the following method.
The results are shown in Table 2.

<<Measurement of the amount of hydrogel exuded on the nonwoven fabric>>
The nonwoven fabric portion was peeled off from the test piece after storage, and the weight (x) was measured. The non-woven fabric portion was thoroughly washed with running water, drained, spread on a paper towel (Eriere Prowipe Soft Towel White; manufactured by Daio Paper Co., Ltd.), and dried at room temperature for 1 week. The weight after drying (y; about 0.9 g) was measured, and the weight difference before and after washing and drying (xy; unit g) was determined, which was used as an index for evaluating the amount of the hydrogel exuded to the nonwoven fabric.
When the value is 1 g or more, it can be visually and tactually (exhibiting a sticky feeling, etc.) clearly oozing into the nonwoven fabric, which means that the usability is inferior.

According to the results of Table 2, in Example 5 in which the component (b1) was used alone as the neutralizing acid and in Example 6 in which the component (b1) and the component (b2) were used in combination, the component (b2) was used alone. Compared to Comparative Examples 12 to 13 used, the gel retains good gel strength even when exposed to a harsh storage environment, effectively suppresses the separation of the liquid from the gel while having a high water content, and is excellent in use. It turns out to be a feeling.

Claims (7)

The following components (A), (B), (C), and (D):
(A) Anionic water-soluble polymer compound containing 75% by mass or more of carboxymethyl cellulose or a salt thereof,
(B) a neutralizing acid containing one or more carboxyl group-containing compounds (b1) selected from L-glutamic acid, acetic acid, dimethylhydroxypropionic acid, and nicotinic acid;
(C) Polyvalent metal compound and (D) Water 60 mass% or more and 95 mass% or less, and the mass ratio of the content of the component (A) and the content of the component (B) ((A)/ (B)) is, der Ru hydrogel composition 4 to 30. The hydrogel composition according to claim 1, wherein the component (B) contains 20% by mass or more and 100% by mass or less of L-glutamic acid. The component (B) further contains one or more carboxyl group-containing compounds (b2) selected from maleic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, phthalic acid, and L-aspartic acid. Item 3. A hydrogel composition according to item 1 or 2. The hydrogel composition according to any one of claims 1 to 3, wherein the component (C) is a compound containing aluminum or a salt thereof. The hydrogel composition according to any one of claims 1 to 4, wherein the content of the component (A) is 2.2% by mass or more and 6% by mass or less. The hydrogel composition according to any one of claims 1 to 5, wherein the content of the component (B) is 0.1% by mass or more and 1.2% by mass or less. A patch comprising the hydrogel composition according to any one of claims 1 to 6 and a base material layer selected from a non-woven fabric, a woven fabric, a knitted fabric and paper.