Application of salt-sensitive hydrogel as intelligent water control and replenishing material

Abstract

Disclosed is the use of a salt-sensitive hydrogel as an intelligent water-control and water-replenishing material. The salt-sensitive hydrogel, which has the property of releasing water in the presenc

Description

FIELD OF TECHNOLOGY The present disclosure relates to the technical field of cosmetics, and specifically relates to an application of a salt-sensitive hydrogel as an intelligent water control and replenishing material. BACKGROUND Due to the influence of the salt intake amount, the sweat excretion amount, the air dust amount, the cleaning degree and other factors, the salt content on the surface of the skin varies from person to person, and the salt content in different parts of the face of the same person also varies. For example, as the environment in inland areas is more arid than that in coastal areas, the salt content on the skin of persons is relatively higher. Especially, as persons living in saline-alkali areas often wash faces with water with high salt content, the skin is likely to be damaged, leading to the problems of dryness and peeling, and severe persons may suffer from dermatitis and other skin diseases. As persons engaged in outdoor works, such as traffic police men and tour guides, are exposed to the sun or wind frequently, the skin surface has the problems of low water content and high salt content. After persons, such as athletes, fitness trainers and dieters, have completed a lot of exercise, the salt content on the surface of the skin is significantly increased than that before exercise. Due to different salt contents, the surface of the skin has different water requirements. For example, when the salt content is high, a large amount of water is required for replenishment. Otherwise, high osmotic pressure may be caused by high salt concentration, leading to absorption of water from the superficial surface of the skin, and as a result, the effects of water replenishing and skin care are not achieved. At present, water replenishing products on the market have low pertinence, relatively general effects and monotonous action mechanisms, and water replenishing products having high pertinence based on different salt contents on the surface of the skin are in shortage. Thus, “targeted treatment” cannot be achieved. Therefore, the situations are caused that the same product usually has mixed praised or criticized public reviews and serious polarization of public opinions, not only being unfavorable to selling of products, but also bringing great difficulties for consumers to choose suitable products. SUMMARY In view of the technical problem that water replenishing products specially developed for skins with different salt contents are in shortage at present, the present disclosure provides an application of a salt-sensitive hydrogel as an intelligent water control and replenishing material. Salt-sensitive hydrogels, including polyglutamic acid, which have the property of releasing water when exposed to salt, exhibit significantly reduced swelling ratio or water absorption capacity and release water under the action of externally added salt.. Based on the property, the present disclosure provides an application of an intelligent water replenishing hydrogel capable of releasing water to different degrees according to different salt contents on surfaces of skins. Specifically, the application may be in the form of a mask. The salt-sensitive hydrogel selected by the present disclosure has a good moisturizing property and non-stickiness, and can effectively release water to a salty skin, so as to achieve the purpose of intelligent water control. The application of the present disclosure can effectively fill the blank in the market, and has a broad market application prospect. An application of a salt-sensitive hydrogel as an intelligent water control and replenishing material is provided. The salt-sensitive hydrogel having a water releasing property in the presence of a salt is applied to a surface of a skin for adapting to the salt content on the surface of the skin so as to replenish an appropriate amount of water. Further, the salt-sensitive hydrogel includes a combination of one or more of a polyglutamic acid hydrogel, a hyaluronic acid hydrogel and a xanthan gum hydrogel. Further, a method for preparing the salt-sensitive hydrogel includes: (1) mixing an aqueous solution of a salt-sensitive substance with a concentration of 0.1 -0.2 g / mL with a cross-linking agent, followed by heating in a water bath for a cross-linking reaction to obtain a salt-sensitive gel block; and (2) adding the salt-sensitive gel block into water, and breaking the salt-sensitive gel block by homogenization to a uniform fluid state to obtain the salt-sensitive hydrogel. According to the present disclosure, the aqueous solution of the salt-sensitive substance with a concentration of 0.1-0.2 g / mL is used for preparing the salt-sensitive hydrogel. The product prepared has good water replenishing and moisturizing effects and non-stickiness, so as to avoid the situation that the solution having too low salt-sensitive concentration has properties similar to water and cannot achieve a good effect. Further, the concentration of the salt-sensitive substance (including polyglutamic acid, hyaluronic acid and / or xanthan gum) in the salt-sensitive hydrogel is 0.001-0.02 g / mL. Further, in step (1), the cross-linking agent is 1,4-butanediol diglycidyl ether, the mass-volume ratio of the salt-sensitive substance to the cross-linking agent is (10-50) g : 1 mL, and the aqueous solution of the salt-sensitive substance and the cross-linking agent are mixed by stirring at 30 °C and 700-1,100 r / min for 30 min, followed by heating in a water bath at 40-62 °C for 5 h to obtain the salt-sensitive gel block under the action of cross-linking. Further, the salt-sensitive hydrogel is loaded on a carrier, the carrier is selected from a nonwoven fabric, gauze, a plant fiber mask paper, a silk mask paper and / or other skin-acceptable mask carriers, and a loading method includes coating the salt-sensitive hydrogel on the surface of the carrier. When the hydrogel is attached to a mask carrier, a good molding effect is achieved by means of a skeleton function of the mask carrier, the face coating time can be effectively shortened, and the use efficiency is improved. Further, the carrier for loading the salt-sensitive hydrogel is dried to obtain a carrier loaded with a dry gel of the salt-sensitive hydrogel, and drying is conducted at 80-100 °C until the water content is less than 5%. Masks for loading different amounts of salt-sensitive hydrogels having different properties can be selectively produced according to packaging or transportation conditions and other factors, so as to provide convenience for consumers in use. Before use, a mask loaded with a dry gel needs to get contact with pure water first and then swells to form a hydrogel for use. The dry carrier is beneficial to long-term storage and transportation, and has a better ability to withstand changes of the ambient temperature. Further, the carrier is further loaded with at least one auxiliary material acceptable to the human body, and the auxiliary material may be a combination of one or more of glycerol, collagen peptide and pro-xylane. Further, the mass of the salt-sensitive hydrogel loaded on the carrier is 0.075-0.3 g / cm2. The present disclosure has the following beneficial effects. According to the present disclosure, by means of characteristics of the salt-sensitive hydrogel, the salt-sensitive hydrogel is used as an intelligent water control and replenishing material, which is free of any preservatives and has safe ingredients. Due to the influence of the salt content on the skin contact surface, the salt-sensitive hydrogel can release water to different degrees to form a local gel dryness and humidity adaptive environment, so that a personalized and regionalized intelligent water replenishing effect is achieved, and the skin contact comfortableness is improved. BRIEF DESCRIPTION OF THE DRAWINGS In order to more clearly illustrate technical solutions in embodiments of the present disclosure or in the prior art, drawings required to be used in descriptions of the embodiments or the prior art are briefly described below. Apparently, other drawings can be obtained by a person of ordinary skill in the art according to these drawings without creative effort. FIG. 1 is a comparison diagram of the stickiness capacity of various groups in Test Example 2; and FIG. 2 is a salt concentration-water releasing amount line chart in Test Example 3. DESCRIPTION OF THE EMBODIMENTS In order to make the technical solutions of the present disclosure better understood by persons in the art, the technical solutions in the embodiments of the present disclosure are clearly and completely described below in combination with the drawings attached to the embodiments of the present disclosure. Obviously, the embodiments described are merely a part, rather than all of the embodiments of the present disclosure. Based on the embodiments of the present disclosure, all other embodiments obtained by a person of ordinary skill in the art without creative effort shall fall within the protection scope of the present disclosure. Example 1 An intelligent water control and replenishing mask includes a 430 cm2 carrier. The surface of the carrier was evenly coated with 60 g of a polyglutamic acid hydrogel, so as to make the polyglutamic acid hydrogel loaded on the carrier. The polyglutamic acid hydrogel was prepared by the following method: (1) accurately weighing 100 g of polyglutamic acid, adding the poly glutamic acid into 1 L of water, conducting uniform stirring to obtain an aqueous solution of the polyglutamic acid with a concentration of 0.1 g / mL, then adding 5 mL of 1,4-butanediol diglycidyl ether into the aqueous solution of the polyglutamic acid, and conducting mixing by stirring at 30 °C and 1,000 r / min for 30 min, followed by heating in a water bath at 60 °C for 5 h to obtain a polyglutamic acid gel block under the action of cross-linking; and (2) adding the polyglutamic acid gel block into water in proportion, and breaking the polyglutamic acid gel block by homogenization to a uniform fluid state to obtain the polyglutamic acid hydrogel with a concentration of 0.003 g / mL. During preparation of the intelligent water control and replenishing mask, other auxiliary materials acceptable to the human body, such as glycerol, can also be loaded on the carrier. Example 2 An intelligent water control and replenishing mask includes a 370 cm2 carrier. The surface of the carrier was loaded with a dry gel of a polyglutamic acid hydrogel. The polyglutamic acid hydrogel was prepared by the following method: (1) accurately weighing 200 g of polyglutamic acid, adding the polyglutamic acid into 1 L of water, conducting uniform stirring to obtain an aqueous solution of the polyglutamic acid with a concentration of 0.2 g / mL, then adding 8 mL of 1,4-butanediol diglycidyl ether into the aqueous solution of the polyglutamic acid, and conducting mixing by stirring at 30 °C and 800 r / min for 30 min, followed by heating in a water bath at 45 °C for 5 h to obtain a polyglutamic acid gel block under the action of cross-linking; and (2) adding the polyglutamic acid gel block into water in proportion, and breaking the polyglutamic acid gel block by homogenization to a uniform fluid state to obtain the polyglutamic acid hydrogel with a concentration of 0.01 g / mL. The carrier was loaded with the dry gel of the polyglutamic acid hydrogel by the following method: (3) evenly coating 30 g of the polyglutamic acid hydrogel on the surface of the carrier, and conducting drying at 90 °C until the water content was less than 5%. During preparation of the intelligent water control and replenishing mask, other auxiliary materials acceptable to the human body, such as glycerol, can also be loaded on the carrier. The intelligent water control and replenishing mask was soaked in 5-10 g of an aqueous solution. After swelling for 2-5 min, cross-linked polyglutamic acid can reach 50-95% (optimal 75-85%) of a saturated water absorption state to achieve convenient use. Example 3 An intelligent water control and replenishing mask includes a 450 cm2 carrier. The surface of the carrier was evenly coated with 50 g of a hyaluronic acid hydrogel, so as to make the hyaluronic acid hydrogel loaded on the carrier. The hyaluronic acid hydrogel was prepared by the following method: (1) accurately weighing 90 g of hyaluronic acid, adding the hyaluronic acid into 1 L of water, conducting uniform stirring to obtain an aqueous solution of the hyaluronic acid with a concentration of 0.09 g / mL, then adding 5 mL of 1,4-butanediol diglycidyl ether into the aqueous solution of the hyaluronic acid, and conducting mixing by stirring at 30 °C and 900 r / min for 30 min, followed by heating in a water bath at 55 °C for 5 h to obtain a hyaluronic acid gel block under the action of cross-linking; and (2) adding the hyaluronic acid gel block into water in proportion, and breaking the hyaluronic acid gel block by homogenization to a uniform fluid state to obtain the hyaluronic acid hydrogel with a concentration of0.006 g / mL. During preparation of the intelligent water control and replenishing mask, other auxiliary materials acceptable to the human body, such as collagen peptide, can also be loaded on the carrier. Example 4 An intelligent water control and replenishing mask includes a 480 cm2 carrier. The surface of the carrier was evenly coated with 40 g of a xanthan gum hydrogel, so as to make the xanthan gum hydrogel loaded on the carrier. The xanthan gum hydrogel was prepared by the following method: (1) accurately weighing 180 g of xanthan gum, adding the xanthan gum into 1 L of water, conducting uniform stirring to obtain an aqueous solution of the xanthan gum with a concentration of 0.18 g / mL, then adding 5 mL of 1,4-butanediol diglycidyl ether into the aqueous solution of the xanthan gum, and conducting mixing by stirring at 30 °C and 950 r / min for 30 min, followed by heating in a water bath at 50 °C for 5 h to obtain a xanthan gum gel block under the action of crosslinking; and (2) adding the xanthan gum gel block into water in proportion, and breaking the xanthan gum gel block by homogenization to a uniform fluid state to obtain the xanthan gum hydrogel with a concentration of 0.003 g / mL. During preparation of the intelligent water control and replenishing mask, other auxiliary materials acceptable to the human body, such as pro-xylane, can also be loaded on the carrier. Comparative Example 1 0.4 g of polyglutamic acid was accurately weighed, added into 10 mL of water and uniformly stirred to obtain an aqueous solution of the polyglutamic acid with a concentration of 0.04 g / mL, then 40 pL of 1,4-butanediol diglycidyl ether was sucked by a pipette and added into the aqueous solution of the polyglutamic acid, and the solution was mixed by stirring at 30 °C and 1,000 r / min for 30 min, followed by heating in a water bath at 60 °C for 5 h to obtain a polyglutamic acid gel block under the action of cross-linking. The polyglutamic acid gel block was added into water in proportion and broken by homogenization to a uniform fluid state to obtain a polyglutamic acid hydrogel with a concentration of 0.01 g / mL. Comparative Example 2 0.01 g / mL agar was added into pure water, heated to 60-80 °C for dissolution in the water and then cooled to room temperature to form a hydrogel. After breaking by homogenization, the hydrogel is free of a salt-sensitive property of releasing water in the presence of a salt and also free of an intelligent water replenishing effect on the surface of the skin. Similarly, collagen also has similar properties, and thus cannot be used as an intelligent water control and replenishing material. Comparative Example 3 2 g of an acrylic acid copolymer (crosslinked) was accurately weighed, added into 10 mL of water and uniformly stirred to obtain an acrylic acid copolymer product with a concentration of 0.2 g / mL. Although the acrylic acid copolymer is a salt-sensitive hydrogel having a water releasing property in the presence of a salt, the acrylic acid copolymer synthesized from petrochemical raw materials is a non-renewable resource, and the acrylic acid copolymer is difficult to degrade naturally, which is not an environmentally friendly green material. Comparative Example 4 An intelligent water control and replenishing mask includes a 430 cm2 carrier. The surface of the carrier was evenly coated with 60 g of a hydroxyethyl cellulose hydrogel, so as to make the hydroxyethyl cellulose hydrogel loaded on the carrier. The hydroxyethyl cellulose hydrogel was prepared by the following method: (1) accurately weighing 100 g of hydroxyethyl cellulose, adding the hydroxyethyl cellulose into 1 L of water, conducting uniform stirring to obtain an aqueous solution of the hydroxyethyl cellulose with a concentration of 0.1 g / mL, then adding 5 mL of 1,4-butanediol diglycidyl ether into the aqueous solution of the hydroxyethyl cellulose, and conducting mixing by stirring at 30 °C and 1,000 r / min for 30 min, followed by heating in a water bath at 60 “C for 5 h to obtain a hydroxyethyl cellulose gel block under the action of cross-linking; and (2) adding the hydroxyethyl cellulose gel block into water in proportion, and breaking the hydroxyethyl cellulose gel block by homogenization to a uniform fluid state to obtain the hydroxyethyl cellulose hydrogel with a concentration of 0.003 g / mL. Although the hydroxyethyl cellulose is a salt-sensitive hydrogel having a water releasing property in the presence of a salt, the hydroxyethyl cellulose is prepared from natural ingredients such as cellulose and obtained by chemical treatment with an organic reagent, an acid, an alkali and the like, and toxic and harmful gases, liquids and other wastes are produced in the preparation process, so that the environmental governance pressure is increased. Comparative Example 5 1 g of polyglutamic acid was accurately weighed, added into 10 mL of water and uniformly stirred to obtain an aqueous solution of the polyglutamic acid with a concentration of 0.1 g / mL. Comparative Example 6 2 g of polyglutamic acid was accurately weighed, added into 10 mL of water and uniformly stirred to obtain an aqueous solution of the polyglutamic acid with a concentration of 0.2 g / mL. Test Example 1 Moisturizing function test With water as a blank control group, a moisturizing property test was carried out on the polyglutamic acid hydrogels in Examples 1 and 2 and the products in Comparative Examples 1 to 4. A method was specifically as follows: cutting a non-woven fabric which has a mass of 0.0825 (±0.0025) g and is capable of properly covering a slide with a size of 7.5 cm*2.5 cm and a mass of about 4.6 g, evenly coating 1 (±0.025) g of a polyglutamic acid hydrogel on the non-woven fabric, then transferring the non-woven fabric together with the slide to a constant-temperature and constant-humidity box at a temperature of 48 °C and a humidity of 36%RH, and recording the total mass of the slide, the non-woven fabric on the cover slide and the product at 0 min, 10 min, 20 min, 30 min, 40 min and 50 min separately. The moisturizing rate of various groups at different time points was calculated according to the following formula. Results are as shown in Table 1. Moisturizing rate=mt / mo, where in the formula, mt refers to the total mass of the slide, the non-woven fabric on the slide and the product in the constant-temperature and constant-humidity box at the time point t, and mo refers to the total mass of the slide, the non-woven fabric on the slide and the product before transferred to the constant-temperature and constant-humidity box. Table 1 Statistical table of the moisturizing rate of various groups at different time points Time Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Blank control Omin 100% 100% 100% 100% 100% 100% 100% lOmin 82% 83% 77% 80% 80% 81% 74% 20min 63% 60% 51% 62% 60% 61% 48% 3 Omin 56% 54% 49% 55% 53% 54% 46% 40min 18% 16% 13% 16% 17% 16% 12% 50min 14% 12% 6% 13% 12% 14% 5% From Table 1, it can be seen that the moisturizing property of various groups is reduced gradually with the increase of the time, and at each test time point, the moisturizing rate in Examples 1 and 2 is higher than that in Comparative Example 1 and the blank control group. The moisturizing rate in Comparative Example 1 is slightly higher than that in the blank control group, and the two values have a small difference, and the results are indicating that the polyglutamic acid hydrogel prepared from the aqueous solution of the polyglutamic acid with a concentration of 0.1-0.2 g / mL has a good moisturizing property. Meanwhile, the moisturizing rate in Comparative Examples 2 to 4 is higher than that in Comparative Example 1 and the blank control group, indicating that these substances also have a good moisturizing property. The hydrogel in Comparative Example 3 synthesized from petrochemical raw materials is a non-renewable resource, and the acrylic acid copolymer is difficult to degrade naturally, which is not an environmentally friendly green material. The hydrogel in Comparative Example 4 is obtained by chemical treatment with an organic reagent, an acid, an alkali and the like, and toxic and harmful gases, liquids and other wastes are produced in the preparation process, so that the environmental governance pressure is increased. Test Example 2 Non-stickiness test A non-stickiness test was carried out on the polyglutamic acid hydrogels in Examples 1 and 2 and the products in Comparative Examples 5 and 6. A method was specifically as follows: coating 1 g of samples of various groups on a glass slide separately, evenly spreading paper scraps on the glass slide, placing the glass slide in an oven at 80 °C, taking out the glass slide after water is evaporated, vertically placing the glass slide until the unsticked paper scraps fall down, and recording the total mass of the glass slide, the product and the sticked paper scraps at this time point. The stickiness capacity of various groups was calculated according to the following formula. A lower stickiness capacity indicates a better non-stickiness effect. Results are as shown in FIG. 1. Stickiness capacity=m’-m, where in the formula, m’ refers to the total mass of the glass slide, the product and the sticked paper scraps after drying; and m refers to the total mass of the glass slide and the product before drying. As shown in FIG. 1, the polyglutamic acid hydrogels in Examples 1 and 2 are less stickier, while the polyglutamic acid without cross-linking in Comparative Examples 5 and 6 are much stickier. Test Example 3 Water replenishing function test A water replenishing function test was carried out on the salt-sensitive hydrogels in Examples 1 to 4 and the products in Comparative Examples 1 and 2. A method was specifically as follows: cutting non-woven fabrics which have a mass of 0.0825 (±0.0025) g and are capable of properly covering glass slides with a size of 7.5 cm*2.5 cm and a mass of about 4.6 g, and evenly coating 1 (±0.025) g of the polyglutamic acid hydrogel in Example 1 on the non-woven fabrics to prepare three hydrogel glass slides; cutting non-woven fabrics which have a mass of 0.0825 (±0.0025) g and are capable of properly covering glass slides with a size of 7.5 cm*2.5 cm and a mass of about 4.6 g, and evenly coating 1 (±0.025) g of NaCl aqueous solutions with a concentration of 0, 0.9% and 1.8% on the non-woven fabrics respectively; and vertically combining the three hydrogel glass slides in Example 1 with the cover slides of the NaCl aqueous solutions (water) with a concentration of 0, 0.9% and 1.8% respectively, recording water releasing situations, and drawing a salt concentration-water releasing amount line chart. The hydrogels in Examples 2 to 4 and Comparative Examples 1 and 2 were treated by the same method. As shown in FIG. 2, when the concentration of the NaCl aqueous solution is 0, no liquid flows out in each group; when the concentration of the NaCl aqueous solution is 0.9%, more water is released out in Examples 1 to 4 than that in Comparative Examples 1 and 2; and when the concentration of the NaCl aqueous solution is 1.8%, the water releasing amount in Examples 1 to 4 is much more than that in Comparative Examples 1 and 2, and particularly, the water releasing amount in Example 2 is greater than 0.1 g. It is indicated that the polyglutamic acid hydrogel in an intelligent water control mask can release water in a salt and release different amounts of water according to different salt contents. When the salt content is high, a large amount of water is released. Thus, the polyglutamic acid hydrogel is extremely suitable for being applied as an intelligent water control mask for people with high salt content on the surface of the skin. Although the present disclosure has been described in detail by referring to the attached drawings in combination with preferred embodiments, the present disclosure is not limited thereto. On the premise of not departing from the spirit and essence of the present disclosure, various equivalent modifications or substitutions of the embodiments of the present disclosure can be made by a person of ordinary skill in the art, and all the modifications or substitutions shall fall within the covering scope of the present disclosure, or variations or substitutions easily obtained by any technical person familiar with the art within the scope of technologies disclosed by the present disclosure shall fall within the protection scope of the present disclosure.

Claims

18 12241. Use of a salt-sensitive hydrogel as an intelligent water control and replenishing material on the skin surface, wherein the salt-sensitive hydrogel releases water in the presence of a salt so as to replenish an appropriate amount of water, wherein the salt-sensitive hydrogel comprises a combination of one or more of a polyglutamic acid hydrogel, a hyaluronic acid hydrogel and a xanthan gum hydrogel, wherein the salt-sensitive hydrogel is prepared by:(a) mixing an aqueous solution of a salt-sensitive substance with a concentration of 0.1-0.2 g / mL with 1,4-butanediol diglycidyl ether as a cross-linking agent at 30 °C and stirring at 700-1,100 r / min for 30 minutes, wherein the mass-volume ratio of the salt-sensitive substance to the cross-linking agent is 10-50 g : 1 mL,(b) heating the mixture in a water bath at 40-62 °C for 5 h to obtain a salt-sensitive gel block; and(c) homogenizing the salt-sensitive gel block in water, to obtain a uniform salt-sensitive hydrogel wherein tire concentration of the salt-sensitive substance in the salt-sensitive hydrogel is 0.001-0.02 g / mL.

2. The application according to claim 1, wherein the salt-sensitive hydrogel is loaded on a carrier.

3. The application according to claim 2, wherein the carrier is subsequently dried to obtain a carrier loaded with a dry gel of the salt-sensitive hydrogel.

4. The application according to claim 3, wherein the carrier is further loaded with at least one auxiliary material acceptable to the human body.

5. The application according to claim 4, wherein the auxiliary material is a combination of one or more of glycerol, collagen peptide and pro-xylane.

6. The application according to claim 3, wherein the mass of the salt-sensitive hydrogel loadedon the carrier is 0.075-0.3 g / cm218 1224

Images