KR20230158445A - Composition for hydrogel sheet, hydrogel sheet made from the composition and method of manufacturing thereof - Google Patents

Abstract

The present invention includes cellulose ether, a gelling agent, and a gelling promoter, and the viscosity of a 2% by weight aqueous solution of the cellulose ether is measured at 20° C. and 20 rpm with a Brookfield viscometer. It relates to a composition for a hydrogel sheet, characterized in that it is 3 cps to 300 cps, a composition for a hydrogel sheet, a hydrogel sheet manufactured therefrom, and a method for manufacturing the same. According to the present invention, by including the cellulose ether of low viscosity as described above, the composition for hydrogel sheets mixed with the cellulose ether, gelling agent and gelation accelerator is added to hot water and stirred to prepare a composition solution for hydrogel sheets. Bubbles generated during the process can be easily removed through a short-term defoaming process.

Description

Composition for hydrogel sheet, hydrogel sheet manufactured therefrom and method for manufacturing same {COMPOSITION FOR HYDROGEL SHEET, HYDROGEL SHEET MADE FROM THE COMPOSITION AND METHOD OF MANUFACTURING THEREOF}

The present invention relates to a composition for a hydrogel sheet, a hydrogel sheet manufactured therefrom, and a method for producing the same.

Hydrogel is a network of hydrophilic polymer chains using water as a dispersion medium. The hydrogel is insoluble in water and swells, so it can contain a large amount of moisture in its structure, and its flexibility is very similar to natural tissue.

The hydrogel is used in medical fields such as tissue engineering, cell culture, sustained-release drug delivery system, biosensor, soft lens, medical electrode, etc. due to its unique hydrophilicity and flexibility. , In addition, in the cosmetics field, it is used as a mask pack to deliver various effects to the skin, such as moisturizing, nutritional supply, wrinkle improvement, and whitening.

For example, in the case of mask packs, research and development has been actively conducted on ways to manufacture and utilize hydrogel in sheet form. When conventional hydrogels are manufactured in sheet form, hydrogels alone cannot maintain their appearance and are weak in strength, so they are generally used in addition to supports such as synthetic resins, non-woven fabrics, mesh, or nets. However, mask packs based on a support such as non-woven fabric dry easily, have poor adhesion to the skin, and the hydrogel often falls off from the support. In addition, since the support such as the non-woven fabric is manufactured through a chemical process, skin problems may occur when a mask pack using this support is used on the skin, so much evaluation and review was required in terms of safety.

As a method to solve this problem, Patent Document 1 (Korean Patent Publication No. 10-2013-0036543) discloses a hydrogel composition for a mask base that can maintain its shape without a support and a method for producing a hydrogel using the same. I'm doing it. Specifically, the hydrogel composition includes 0.1 to 10% by weight of a crosslinking agent, 0.2 to 6% by weight of a gelling polymer, 0.5 to 20% by weight of a polyhydric alcohol, and 70 to 90% by weight of purified water, and the method for producing the hydrogel is (i) ) Preparing an aqueous solution by adding a crosslinking agent to purified water at room temperature and stirring at a temperature of 40 to 85°C; (ii) preparing a hydrogel composition by dissolving the gelled polymer in polyhydric alcohol at room temperature, adding it to the aqueous solution and stirring at 40 to 80°C; (iii) compression coating the hydrogel composition to a thickness of 0.5 to 2 mm; (iv) cooling the compression-coated hydrogel composition layer at room temperature to produce a hydrogel; and (v) heat treating the cooled hydrogel at a temperature of 40 to 85°C for 12 to 36 hours.

However, according to step (ii), a liquid hydrogel composition is prepared through a heating and stirring process, and during this process, a large number of bubbles may be generated in the liquid hydrogel composition, and the bubbles thus generated cannot be removed. Otherwise, it may have a negative effect on the hydrogel sheet. Specifically, when a large number of bubbles contained in the liquid hydrogel composition remain in the hydrogel sheet and harden, a non-transparent and cloudy hydrogel sheet is produced, which is not only unsatisfactory in appearance, but also the solidified bubbles are 3% of the hydrogel. Disruption of the dimensional network structure causes the problem of deterioration of gel sheet properties such as gel strength.

KR 1020130036543 A

The problem to be solved by the present invention is to provide a composition for a hydrogel sheet from which bubbles generated during the production process of the composition solution for a hydrogel sheet can be easily removed by containing a cellulose ether having a low viscosity. As used herein, “composition solution for hydrogel sheets” refers to a liquid state in which solids are dispersed, dissolved, or partially dissolved in hot water, and includes the concepts of dispersion, solution, or partial solution.

Another problem to be solved by the present invention is to provide a hydrogel sheet manufactured from the above composition with excellent strength and appearance and a method for manufacturing the same.

In order to solve the above problems, the present invention includes cellulose ether, a gelling agent, and a gelling promoter, and the viscosity of a 2% by weight aqueous solution of the cellulose ether is measured using an Ubbelohde viscometer. Provided is a composition for a hydrogel sheet, characterized in that it is 3 cps to 300 cps when measured under conditions of 20°C using (Ubbelohde's viscometer).

The cellulose ethers include methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose. and carboxymethyl cellulose.

The gelling agent may include one or more natural polymers selected from the group consisting of carrageenan, locust bean gum, mannose, and water-chestnut flour.

The gelation accelerator may be a salt of a Group 1 or Group 2 metal, and may preferably include at least one selected from the group consisting of magnesium chloride, potassium chloride, calcium chloride, and sodium chloride.

The molar ratio of the repeating unit of the gelling agent per glucose unit of the cellulose ether may be 0.01 to 12.00, and the molar ratio of the gelation accelerator may be 0.01 to 2.00.

The viscosity of the 5% by weight aqueous solution of the hydrogel sheet composition may be 500cps to 5000cps when measured with a Brookfield viscometer at 60°C and 15 to 60 rpm.

In addition, the present invention provides a hydrogel sheet manufactured from the composition for hydrogel sheet.

The hydrogel sheet may have a porosity of 0.01% to 5%.

The hydrogel sheet can be used as a cosmetic mask pack or as a wound coating material.

In addition, the present invention provides a method for manufacturing a hydrogel sheet prepared from the composition for a hydrogel sheet, the manufacturing method comprising the steps of mixing a cellulose ether, a gelling agent, and a gelation accelerator to prepare a composition for a hydrogel sheet; Preparing a composition solution for a hydrogel sheet by adding the composition for a hydrogel sheet to hot water and stirring it; Defoaming by levitating air bubbles in the hydrogel sheet composition solution; Casting the hydrogel sheet composition solution that has undergone the defoaming step into a sheet form; and gelling the composition solution for a hydrogel sheet in the form of a cast sheet.

The temperature of the hot water may be 70°C to 100°C.

The defoaming step may be performed by maintaining the hydrogel sheet composition solution at 55°C to 65°C for 20 to 60 minutes.

The viscosity of the hydrogel sheet composition solution (solid content: 5% by weight) that has gone through the defoaming step may be 500 cps to 5000 cps when measured at 60°C and 15 to 60 rpm with a Brookfield viscometer.

According to the present invention, the composition for hydrogel sheets includes cellulose ether in which a 2% by weight aqueous solution has a viscosity of 3 cps to 300 cps, and the composition for hydrogel sheets is added to hot water and stirred to prepare a composition solution for hydrogel sheets. Bubbles generated during the process can be easily removed through a short-term defoaming process.

In this way, as the bubbles contained in the composition solution for a hydrogel sheet are removed, the problem of producing a hydrogel sheet with reduced transparency and a cloudy appearance due to the bubbles can be solved. In addition, the problem of the bubbles interfering with the three-dimensional network structure of the hydrogel, thereby reducing the gel sheet physical properties such as gel strength, can be solved.

Figure 1 shows a photograph of a hydrogel sheet prepared according to Example 1.
Figure 2 shows a photograph of the hydrogel sheet prepared according to Comparative Example 1.

The present invention relates to a composition for a hydrogel sheet, a hydrogel sheet manufactured therefrom, and a method for producing the same.

First, looking at the composition for a hydrogel sheet, the composition includes cellulose ether, a gelling agent, and a gelling promoter, and the viscosity of a 2% by weight aqueous solution of the cellulose ether is Ubbelo. When measured with a viscometer under conditions of 20°C, it is characterized as 3cps to 300cps.

Hydrogel is a three-dimensional network structure formed by cross-linking hydrophilic polymer chains, and is a material that contains water but is insoluble in water. Hydrophilic polymers have polar groups with strong hydrophilicity, and these polar groups form a three-dimensional network structure through covalent bonds, ionic bonds, hydrogen bonds, or van der Waals bonds.

Cellulose ether included in the composition for hydrogel sheet refers to a cellulose derivative in which the hydroxyl group of cellulose is etherified.

The viscosity of a 2% by weight aqueous solution of cellulose ether according to the present invention has a low viscosity range of 3 to 300 cps when measured at 20°C with an Ubbelohde viscometer. The present inventors recognized that during the process of preparing a composition solution for a hydrogel sheet, a large amount of bubbles are generated in the solution and that if the generated bubbles are not removed, they have a negative effect on the physical properties of the hydrogel sheet. Accordingly, as a result of intensive research efforts to solve this problem, it was confirmed that when using cellulose ether with a low viscosity range as described above, air bubbles can be easily removed through a short-time defoaming process after preparing the composition solution for hydrogel sheets. And the present invention was completed.

The cellulose ethers include methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose. and carboxymethyl cellulose.

The composition for the hydrogel sheet may use a gelling agent for gel formation, strength control, syneresis control, and improvement of feeling of use. As the gelling agent, natural polymers can be used rather than water-soluble synthetic polymers to eliminate toxicity to the skin. As such gelling agents, commonly used natural polymer gelling agents can be used without limitation, for example, carrageenan, locust bean gum, mannose, and water-chestnut flour. One or more types selected from the group consisting of may be used. In particular, when the carrageenan is used alone or in combination with carrageenan and another gelling agent, it is preferable to produce a hydrogel that can be gelled at room temperature and has excellent gel strength.

A gelation accelerator may be used to improve the mechanical properties of the natural polymer material. The gelation accelerator serves to crosslink the natural polymer material. The gelation accelerator may be a salt of a Group 1 or Group 2 metal, and may preferably contain at least one selected from the group consisting of magnesium chloride, potassium chloride, calcium chloride, and sodium chloride.

The molar ratio of the repeating unit of the gelling agent per glucose unit of the cellulose ether may be 0.01 to 12.00, and the molar ratio of the gelation accelerator may be 0.01 to 2.00. If the repeating unit molar ratio of the gelling agent is less than 0.01 per glucose unit of the cellulose ether, the viscosity is too low and gel formation is difficult, and there is a risk that the gel characteristics may not be displayed. On the other hand, if it exceeds 12.00, the hardness of the gel If it becomes too high, there is a risk that adhesion to the skin may decrease and the feeling of use may deteriorate. In addition, if the molar ratio of the gelation accelerator is less than 0.01 per glucose unit of the cellulose ether, the strength of the gel is too low and there is a risk of the gel becoming brittle and tearing. On the other hand, if it exceeds 2.00, the hardness of the gel is too high. There is a risk that adhesion to the skin may decrease.

The viscosity of the 5% by weight aqueous solution of the composition for the hydrogel sheet provided according to the present invention may be 500cps to 5000cps when measured under conditions of 60°C and 15 to 60 rpm with a Brookfield viscometer. At this time, the viscosity of the aqueous solution of the composition for hydrogel sheets is measured by measuring the viscosity of the solution of the composition for hydrogel sheets that has gone through the degassing process.

Meanwhile, the present invention provides a hydrogel sheet manufactured from the composition for a hydrogel sheet according to the above.

The hydrogel sheet may have a porosity of 0.01% to 5%. If the porosity is less than 0.01%, there is a risk that the economic feasibility of the manufacturing process will decrease. On the other hand, if it exceeds 5%, the strength of the hydrogel sheet decreases and it looks cloudy, so there is a risk of poor appearance. At this time, the porosity can be calculated using the density of the sheet measured by measuring the weight and volume of the hydrogel sheet and the density of the sheet calculated theoretically.

The hydrogel sheet can be widely applied in the medical and cosmetic fields, and can preferably be used as a cosmetic mask pack or as a wound covering material.

In addition, the present invention provides a method for producing the hydrogel sheet, which includes preparing a composition for a hydrogel sheet by mixing cellulose ether, a gelling agent, and a gelling accelerator; Preparing a composition solution for a hydrogel sheet by adding the composition for a hydrogel sheet to hot water and stirring it; Defoaming by levitating air bubbles in the hydrogel sheet composition solution; Casting the hydrogel sheet composition solution that has undergone the defoaming step into a sheet form; and gelling the cast composition solution for a hydrogel sheet in the form of a sheet.

Hereinafter, the method for manufacturing a hydrogel sheet according to an embodiment of the present invention will be described step by step in detail.

(1) Step of preparing composition for hydrogel sheet

This step is to prepare a composition for a hydrogel sheet by mixing the cellulose ether, gelling agent, and gelation accelerator. At this time, the characteristics of each composition, such as the viscosity and type of the cellulose ether, and the type and content (molar ratio) of the gelling agent and gelling accelerator, are as described above.

When a composition for a hydrogel sheet is prepared by mixing a cellulose ether, a gelling agent, and a gelling accelerator as described above, and then adding the composition for a hydrogel sheet to hot water and stirring according to step (2), which will be described later, each cellulose ether, Compared to the case where the gelling agent and gelling accelerator are gradually added to hot water and stirred, the process time required for the degassing process according to step (3), which will be described later, can be shortened.

(2) Step of preparing composition solution for hydrogel sheet

This step is to prepare a composition solution for a hydrogel sheet by dispersing and partially dissolving the hydrogel sheet composition in hot water and stirring.

The temperature of the hot water may be 70°C to 100°C. At this time, if the temperature of the hot water is less than 70°C, dispersion and partial dissolution of the composition for the hydrogel sheet may not occur well, so it may be difficult to prepare the composition solution for the hydrogel sheet, which may result in a decrease in the physical properties of the hydrogel sheet. there is.

In the process of preparing the composition solution for hydrogel sheets by dispersing and partially dissolving the composition for hydrogel sheets in hot water, physical force is applied using a mechanical stirrer. At this time, a large amount of bubbles are generated in the solution. I do it. If air bubbles are not removed from the solution, it will have a negative effect on the mechanical properties, such as appearance and strength, of the hydrogel sheet manufactured from the composition, and therefore, the defoaming step (3), which will be described later, is performed to remove air bubbles.

(3) Defoaming step

This step is a step of defoaming by levitating air bubbles in the hydrogel sheet composition solution.

The defoaming step may be performed by maintaining the hydrogel sheet composition solution at 55°C to 65°C for 20 to 60 minutes. When preparing a composition solution for a hydrogel sheet according to step (2) using a composition for a hydrogel sheet containing a cellulose ether having a low viscosity in the range of 3 cps to 300 cps according to the present invention, bubbles generated in the solution Can be naturally floated and removed in the range of 55 to 65°C. At this time, when the solution is maintained in the above temperature range, process efficiency can be improved because bubbles in the solution can be removed within 1 hour.

As the air bubbles contained in the composition solution for a hydrogel sheet are easily removed through this short-term degassing process, problems caused by the bubbles, such as the bubbles interfering with the three-dimensional network structure of the hydrogel, reduce the gel strength. It is possible to solve the problem of deteriorating the quality of the hydrogel sheet by lowering the physical properties of the gel sheet or giving it a cloudy and cloudy appearance.

Since the composition for hydrogel sheets according to the present invention contains low viscosity cellulose ether, the viscosity of the composition solution for hydrogel sheets (5% by weight of solids) that has gone through the degassing step is measured at 60°C and 15 to 60 rpm using a Brookfield viscometer. When measured under certain conditions, it can be 500cps to 5000cps.

(4) Casting step

This step is a step of casting the hydrogel sheet composition solution that has gone through the degassing step into a sheet form.

Specifically, the defoamed composition solution for a hydrogel sheet can be produced into a hydrogel sheet by casting it to a thickness of 0.1 mm to 10.0 mm at room temperature. If the thickness is less than 0.1 mm, tearing problems may occur due to a decrease in the strength of the hydrogel sheet, while if it exceeds 10 mm, skin adhesion may be significantly reduced and delivery efficiency of the active ingredient may be reduced.

(5) Gelation step

This step is a step of gelling the composition solution for a sheet-shaped hydrogel sheet that has gone through the casting step.

The gelation may be performed according to a conventional method belonging to the field of the present invention. For example, when carrageenan is used alone as a gelling agent or a combination of carrageenan and another gelling agent is used, it may be carried out by leaving it naturally at room temperature. You can.

Hereinafter, the present invention will be described in more detail through examples, but the present invention is not limited to these examples.

Example 1

A composition for a hydrogel sheet was prepared by mixing hydroxypropyl methyl cellulose (HPMC) (HPMC 2910, manufactured by Lotte Fine Chemical Co., Ltd.), carrageenan (MSC), locust bean gum (LBG Sicilia), and potassium chloride (Sigma Aldrich). Manufactured. At this time, per 1 mole of glucose unit of the HPMC, the carrageenan was mixed at a molar ratio of 0.3 mole, the locust bean gum was 0.1 mole, and the potassium chloride was 0.07 mole. That is, the HPMC, gelling agent (carrageenan + locust bean gum), and potassium chloride were mixed at a molar ratio of 1:0.4:0.07. In addition, the viscosity of a 2% by weight aqueous solution of hydroxypropyl methylcellulose is 15 cps when measured at 20°C with an Ubbelohde viscometer.

Next, the composition for a hydrogel sheet was added to hot water at 85°C and stirred to prepare a composition solution for a hydrogel sheet. At this time, the total solid content (composition for hydrogel sheets) in the hydrogel sheet composition solution is 5% by weight.

Next, the hydrogel sheet composition solution was left at 60°C for 60 minutes to perform a degassing process in which bubbles generated in the solution naturally floated and were released to the outside. At this time, the viscosity of the hydrogel sheet composition solution (solid content 5% by weight) that has gone through the degassing process is 1677cps when measured at 60°C and 60rpm with a Brookfield viscometer.

Next, the composition solution for a hydrogel sheet that had gone through the degassing process was cast to a thickness of 0.1 mm under room temperature conditions and then gelled to prepare a hydrogel sheet.

Examples 2 to 4 and Comparative Examples 1 to 2

A hydrogel sheet was prepared in the same manner as in Example 1, except that the viscosity of the 2% by weight aqueous solution of HPMC and the viscosity of the hydrogel sheet composition solution that had undergone the degassing process were changed as shown in Table 1 below.

Evaluation example 1

The state of bubbles remaining in the hydrogel sheet composition solution left at 60°C for 60 minutes according to Examples 1 to 4 and Comparative Examples 1 to 2, that is, the degassing state, was observed with the naked eye.

In Table 1 below, “×” indicates that almost all bubbles have floated, so the solution is transparent and clear, with only a few bubbles remaining at the top. In addition, "△" indicates a state in which the lower part of the solution is clear, but the upper part is covered with a thick layer of bubbles, and "○" indicates a state in which bubbles remain throughout the entire interior of the solution.

Evaluation example 2

The gel sheet strength of a specimen cut from the hydrogel sheets prepared according to Examples 1 to 4 and Comparative Examples 1 to 2 to 7 cm x 7 cm was measured, and the results are shown in Table 1 below. At this time, the measurement conditions are as follows.

- Device: CT3 Texture Analyzer (Brookfield)

- Probe: TA41 (Cyliderical probe)

- Fixture base table: Ta-BT-KTI

- Test type: compression

- Target type: Distance

- Target value: 30mm

-Trigger load: 2g

- Test speed: 0.5 mm/s

HPMC viscosity (cps) Viscosity of composition for hydrogel sheet (cps) Defoamed state Gel sheet strength (g) Example 1 15 1677 × 101.5 Example 2 150 3354 × 100.8 Example 3 200 3818 × 93.4 Example 4 300 4184 × 89.3 Comparative Example 1 400 5562 △ 74.3 Comparative Example 2 500 6202 ○ 74.8

Looking at Table 1, in the case of Examples 1 to 4 containing HPMC with a 2% by weight aqueous solution having a viscosity of 3cps to 300cps, the viscosity of the composition solution for a hydrogel sheet (5% by weight of solids) that has undergone a degassing process is 500cps to 500cps. It can be confirmed that it falls within the range of 5000cps, and in this case, after a 60-minute degassing process, almost all bubbles floated, and the composition solution for hydrogel sheets was transparent and clear, with only a few bubbles remaining at the top. . On the other hand, in the case of the hydrogel sheet composition solutions according to Comparative Examples 1 to 2 prepared from the hydrogel sheet composition containing HPMC outside the above viscosity range, a thick layer of bubbles was formed on the top even after a 60-minute defoaming process. It indicates a state of being covered or of bubbles remaining throughout the entire solution. Figures 1 and 2 show photographs of the hydrogel sheet prepared according to Example 1 and Comparative Example 1, respectively. Looking at Figures 1 and 2, it can be seen that while no bubbles were observed in the hydrogel sheet prepared according to Example 1, a large amount of bubbles were found in the hydrogel sheet prepared according to Comparative Example 1.

In addition, it can be seen that the hydrogel sheets prepared according to Examples 1 to 4 have higher strength compared to the hydrogel sheets prepared according to Comparative Examples 1 to 2.

As described above, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but rather to explain the scope of the present invention, and the scope of rights of the present invention should be interpreted in accordance with the scope of the patent claims below, and all technical ideas within the equivalent scope thereof should be interpreted. should be interpreted as included in the scope of rights of the present invention.

Claims (11)

Preparing a composition for a hydrogel sheet by mixing a cellulose ether, a gelling agent, and a gelling accelerator having a 2% by weight aqueous solution of cellulose ether with a viscosity of 3 cps to 300 cps as measured at 20°C with an Ubbelohde viscometer;
Preparing a composition solution for a hydrogel sheet by adding the composition for a hydrogel sheet to hot water at 70°C to 100°C and stirring it;
Defoaming by levitating air bubbles in the hydrogel sheet composition solution;
Casting the hydrogel sheet composition solution that has undergone the defoaming step into a sheet form; and
Comprising the step of gelling the composition solution for a hydrogel sheet in the form of a cast sheet,
A method of producing a hydrogel sheet, characterized in that the viscosity of the composition solution for a hydrogel sheet (5% by weight of solids) that has gone through the defoaming step is 500 cps to 5000 cps when measured at 60 ° C. and 15 to 60 rpm with a Brookfield viscometer. . According to paragraph 1,
The defoaming step is a hydrogel sheet manufacturing method, characterized in that performed by maintaining the hydrogel sheet composition solution at 55 ° C. to 65 ° C. for 20 minutes to 60 minutes. According to paragraph 1,
The cellulose ethers include methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose. and carboxymethyl cellulose. According to paragraph 1,
The gelling agent is characterized in that it contains at least one natural polymer selected from the group consisting of carrageenan, locust bean gum, mannose, and water-chestnut flour. Hydrogel sheet manufacturing method. According to paragraph 1,
A method for producing a hydrogel sheet, characterized in that the gelation accelerator is a salt of a Group 1 or Group 2 metal. According to clause 5,
A method of producing a hydrogel sheet, wherein the gelation accelerator includes at least one selected from the group consisting of magnesium chloride, potassium chloride, calcium chloride, and sodium chloride. According to paragraph 1,
A method for producing a hydrogel sheet, characterized in that the molar ratio of the repeating unit of the gelling agent per glucose unit of the cellulose ether is 0.01 to 12.00, and the molar ratio of the gelation accelerator is 0.01 to 2.00. A hydrogel sheet manufactured by the hydrogel sheet manufacturing method according to claim 1. According to clause 8,
The hydrogel sheet is characterized in that the hydrogel sheet has a porosity of 0.01% to 5%. According to clause 8,
The hydrogel sheet is characterized in that it is used as a cosmetic mask pack. According to clause 8,
A hydrogel sheet, characterized in that the hydrogel sheet is used as a wound coating material.