A dry high-temperature resistant hydrogel and preparation method thereof

Abstract

The present invention belongs to the field of materials, and specifically relates to a dry high-temperature resistant hydrogel and a preparation method thereof. The present invention adopts a method of physically cross-linking a water-soluble thickener, a chelating agent, and a cross-linking agent, supplemented by a compound, so as to enhance the interaction force between molecules in the hydrogel, especially the hydrogen bonding effect, so as to improve the stability of the hydrogel structure, and thus achieve the purpose of high temperature resistance. The preparation process of the dry high-temperature resistant hydrogel involved in the present invention is simple, the raw materials are easy to obtain, the cost is low, and mass production can be achieved. The hydrogel prepared by the method of the present invention has high thermal stability and can still maintain structural stability after being boiled in water at 90°C for more than 6 hours; and has good water absorption rate, moderate hardness and softness, and a strong gel feel, and can be well used in medical dressings, daily chemicals and other fields.

Description

Technical Field

[0001] The present invention relates to the field of polymer materials, and in particular to a dry high-temperature resistant hydrogel and a preparation method thereof. Background Art

[0002] Hydrogels are gels dispersed in water. They possess a polymer network system, are flexible, maintain a defined shape, and can absorb large amounts of water. This significantly addresses shortcomings such as low adsorption capacity, insufficient water retention, and poor skin adhesion, resulting in significant application potential. In recent decades, hydrogels have attracted widespread attention from scientists, engineers, and business professionals. Currently, their applications have expanded to include high-absorbency materials, the food industry, medical dressings, contact lenses, sustained-drug delivery matrices, chemical valves, soft tissue fillers, and facial mask matrix materials. Hydrophilic facial masks made from hydrogels are particularly popular among consumers due to their transparency, natural properties, safety, and rich water content.

[0003] Existing hydrogels on the market are primarily composed of carrageenan-based polysaccharides, supplemented with potassium and calcium salts, and are produced through physical crosslinking. Polysaccharides themselves are susceptible to hydrolysis, and hydrogels primarily exist in a wet state in actual products. This is further exacerbated by high summer temperatures and the high temperatures of containers during truck transportation. Patent CN201410226170.1 describes a high-temperature-stable hydrogel facial mask that is only stable below 55°C and has a complex raw material composition and high cost. Summary of the Invention

[0004] In view of the defects of the prior art, the purpose of the present invention is to provide a dry high-temperature resistant hydrogel and its preparation method which is low in cost, simple in process, resistant to high temperature, has good water absorption rate, moderate hardness and softness, and strong gel feeling.

[0005] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0006] In one aspect, a method for preparing a dry high-temperature resistant hydrogel comprises the following steps:

[0007] (1) Put a water-soluble thickener, a chelating agent, and a cross-linking agent into a beaker, add an organic solvent, and stir to obtain a mixture A;

[0008] (2) adding an acid or an acid aqueous solution to the mixture A and stirring to obtain a mixture B;

[0009] (3) adding the compound to mixture B and stirring to obtain mixture C;

[0010] (4) vacuum degassing the mixture C, coating the material, and then drying it to obtain a dry high-temperature resistant hydrogel;

[0011] Preferably, the water-soluble thickener is an organic synthetic water-soluble polymer; more preferably, the water-soluble thickener is sodium polyolefin acid; further preferably, the water-soluble thickener is sodium polyacrylate.

[0012] Preferably, the chelating agent is one or more of disodium EDTA, tetrasodium EDTA, and dipotassium EDTA.

[0013] Preferably, the cross-linking agent is an organic or inorganic aluminum salt; further preferably, the cross-linking agent is one or more of aluminum chloride, aluminum glycolate, aluminum sulfate, alum, aluminum hydroxide, aluminum silicate, aluminum nitrate, and aluminum oxide.

[0014] Preferably, the organic solvent is one or more of glycerol, polyethylene glycol-200, polyethylene glycol-400, polyethylene glycol-600, polyglycerol-10, methoxy polyethylene glycol 1000 methacrylate, polyethylene oxide polypropylene oxide monobutyl ether, polyoxyethylene polyoxypropylene ether, polyethylene glycol and propylene glycol copolymer, and ethylhexyl palmitate.

[0015] Preferably, the acid or acid aqueous solution is one or more of tartaric acid aqueous solution, citric acid aqueous solution, oxalic acid aqueous solution, lactic acid aqueous solution, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, acetic acid, and oxalic acid.

[0016] Preferably, the compound is one or more of polyvinyl alcohol, polyvinyl pyrrolidone, sodium carboxymethyl cellulose, hydroxyethyl cellulose, locust bean gum, kaolin, bentonite, polyurethane emulsion, printing paste, glycerol polyacrylate, rosin glycerol ester, acrylic polymer emulsion, and acrylic copolymer emulsion.

[0017] Preferably, the substrate used for coating in step (4) is any one of non-woven fabric, POPP film, and PET film.

[0018] Preferably, the mass ratio of the water-soluble thickener, the chelating agent and the cross-linking agent is 40-2200:1:2-2100.

[0019] Preferably, the mass ratio of the organic solvent to the water-soluble thickener is 2 to 100:1.

[0020] More preferably, the mass ratio of the organic solvent to the water-soluble thickener is 3 to 5:1.

[0021] Preferably, the mass ratio of the acid or the acid aqueous solution to the water-soluble thickener is 1:1 to 30.

[0022] More preferably, the mass ratio of the acid or the acid aqueous solution to the water-soluble thickener is 1:3-12.

[0023] Preferably, the mass ratio of the compound to the water-soluble thickener is 1:0.1-10.

[0024] Further preferably, the mass ratio of the compound to the water-soluble thickener is 1:0.8-2.

[0025] Preferably, in step (4), the drying temperature is 40-180° C., and the drying time is 1-120 min.

[0026] More preferably, in step (4), the drying temperature is 50-145° C., and the drying time is 2-60 min.

[0027] On the other hand, the present invention provides a dry high-temperature resistant hydrogel prepared by the preparation method as described above, and the use of the dry high-temperature resistant hydrogel prepared by the preparation method as described above as a medical dressing matrix material, a facial mask matrix material or a water-absorbing material.

[0028] The dry high-temperature resistant hydrogel involved in the present invention is prepared using the above-mentioned specific preparation method. The various process parameters and reaction conditions are mutually restrained and coordinated as a whole, which can achieve better results in improving the structural stability and water absorption of the hydrogel.

[0029] The present invention adopts sodium polyacrylate as a thickener, adds disodium EDTA or tetrasodium EDTA as a chelating agent, and aluminum salt or aluminum oxide / hydroxide as a crosslinking agent, performs physical crosslinking under specific parameter conditions, and then adds a compound with a thickening effect. The obtained crosslinked product has stronger intermolecular forces, especially stronger hydrogen bonding, so that the obtained hydrogel has better high temperature resistance.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention adopts a method of physically cross-linking a water-soluble thickener, a chelating agent and a cross-linking agent, supplemented by a compound, to improve the stability of the hydrogel structure.

[0032] The hydrogel prepared by the method of the present invention has high thermal stability and can maintain stable morphology and properties under high temperature conditions of 90°C.

[0033] Furthermore, the hydrogel prepared by the present invention has high thermal stability even in a wet state and can be quickly dried under high temperature conditions, thereby greatly shortening the process time and reducing production costs.

[0034] Furthermore, the present invention selects relatively stable sodium polyacrylate as the main raw material for preparing dry high-temperature resistant hydrogel. The hydrogel can be obtained through four steps. The raw materials are easily available, the cost is low, the preparation process is simple, and mass production can be achieved.

[0035] Furthermore, the hydrogel prepared by the method of the present invention has moderate hardness and softness and a strong gel feeling.

[0036] Furthermore, the hydrogel prepared by the method of the present invention has a good water absorption rate and can be well applied in the fields of medicine, daily chemicals and the like. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0038] The raw materials used in the examples and comparative examples of the present invention were all commercially available. The manufacturer of sodium polyacrylate was Jiangmen Xinhui Zhongsheng Biotechnology Co., Ltd., with a model of 3D5 and a mesh size of 90.

[0039] Example 1

[0040] This embodiment provides a high temperature resistant hydrogel, which is prepared by the following method:

[0041] (1) Weigh 9.0g of sodium polyacrylate, 0.2g of disodium EDTA, 0.15g of aluminum sulfate, and 0.55g of alum into a beaker. Add 30.0g of glycerol and pre-disperse. Stir well and set aside.

[0042] (2) Weigh 0.8 g of tartaric acid into a beaker, add 60.0 g of pure water and stir evenly, then add it to the beaker in step (1) and stir thoroughly to mix evenly.

[0043] (3) Weigh 7.0 g of kaolin compound (500 mesh) into a beaker, add 30 g of water and stir evenly, then add to the beaker in step (2) and stir thoroughly to mix evenly.

[0044] (4) The colloid obtained in step (3) is vacuum degassed, coated on a PET film after degassed, and baked in an oven at 100° C. for 5 minutes to obtain a dehydrated high-temperature resistant hydrogel.

[0045] A destructive test was conducted on the product. 200 ml of tap water was added to a water bath and the temperature was kept constant at 65°C. 1 g of the hydrogel prepared in step (3) was taken, wrapped with gauze, and placed in a 65°C water bath and heated for 50 minutes. The hydrogel did not dissolve in water or break, and the gel remained intact as a whole. The hydrogel before and after heating had a moderate hardness and a strong gel feel.

[0046] Example 2

[0047] A high temperature resistant hydrogel is prepared by the following method:

[0048] (1) Weigh 5.5 g of sodium polyacrylate, 0.1 g of tetrasodium EDTA, and 1.4 g of aluminum hydroxide into a beaker, add 25.0 g of polyglycerol-10, stir well, and set aside.

[0049] (2) Weigh 1.5 g of citric acid into a beaker, add 60 g of pure water and stir evenly, then add it to the beaker in step (1) and stir thoroughly to make it uniform.

[0050] (3) Weigh 1.5 g of polyvinyl pyrrolidone into a beaker, add 40 g of pure water and 5 g of polyurethane emulsion and stir evenly, then add to the beaker in step (2) and stir thoroughly to mix evenly.

[0051] (4) The colloid obtained in step (3) is vacuum degassed, coated on a PET film after degassed, and dried in an oven at 95° C. for 8 min to obtain a dehydrated high-temperature resistant hydrogel.

[0052] A destructive test was conducted on the product. 200 ml of tap water was added to a water bath and the temperature was kept constant at 75°C. 1 g of the hydrogel prepared in step (3) was taken, wrapped with gauze, and placed in a 75°C water bath and heated for 30 minutes. The hydrogel did not dissolve in water or break, and the gel remained intact. The hydrogel before and after heating had a moderate hardness and a strong gel feel.

[0053] Example 3

[0054] A high temperature resistant hydrogel is prepared by the following method:

[0055] (1) Weigh 5.0 g of sodium polyacrylate, 0.1 g of disodium EDTA, 1.2 g of aluminum chloride, and 0.8 g of aluminum oxide into a beaker, add 20.0 g of polyethylene glycol-400, stir well, and set aside.

[0056] (2) Measure 12 ml of 5% hydrochloric acid solution, add it to the beaker in step (1), and stir thoroughly to make it uniform.

[0057] (3) Weigh 2.5 g of sodium carboxymethyl cellulose in a beaker, add 80 g of pure water and stir evenly, then add it to the beaker in step (2) and stir thoroughly to mix evenly.

[0058] (4) The colloid obtained in step (3) is vacuum degassed, coated on a PET film after degassed, and baked in an oven at 120° C. for 3 min to obtain a dehydrated high-temperature resistant hydrogel.

[0059] A destructive test was conducted on the product. 200 ml of tap water was added to a water bath and the temperature was kept constant at 90°C. 1 g of the hydrogel prepared in step (3) was taken, wrapped with gauze, and placed in a 90°C water bath and heated for 70 minutes. The hydrogel did not dissolve in water or break, and the gel remained intact as a whole. The hydrogel before and after heating had a moderate hardness and a strong gel feel.

[0060] Example 4

[0061] The thermal stability of the hydrogels obtained in Examples 1-3 was compared with that of the commonly used polysaccharide hydrogels (water silk membrane purchased from Zhuhai Haisi New Material Intelligent Manufacturing Technology Co., Ltd.). The test method was to cut 2g of wet hydrogel and 0.5g of dry hydrogel, wrap them with gauze, and place them in a water bath at 65°C and 90°C containing 100ml of tap water for 6 hours, and add 50 times of pure water at 25°C and let it stand for 6 hours. The dissolution of the hydrogel was observed to judge the thermal stability of the hydrogel. The wet hydrogel was obtained by placing 0.5g of dry hydrogel in 100g of deionized water and absorbing water for 2 hours. The test results are as follows:

[0062]

[0063] As can be seen from the above table, the hydrogel prepared by the method of the present invention has good thermal stability at 65-90°C.

[0064] The applicant states that while the above-described embodiments illustrate a dry, high-temperature-resistant hydrogel and its preparation method, the present invention is not limited to these embodiments. This does not necessarily mean that the present invention must rely on these embodiments for implementation. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for raw materials in the present invention, additions of auxiliary ingredients, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

[0065] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the technical concept of the present invention, various simple variations can be made to the technical solution of the present invention, and these simple variations all fall within the scope of protection of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A method for preparing a dry high-temperature resistant hydrogel, characterized in that: Prepared by the following method: (1) Weigh 5.5g of sodium polyacrylate, 0.1g of tetrasodium EDTA, and 1.4g of aluminum hydroxide into a beaker, add 25.0g of polyglycerol-10, stir well and set aside; (2) Weigh 1.5 g of citric acid into a beaker, add 60 g of pure water and stir evenly, then add it to the beaker in step (1) and stir thoroughly to make it uniform; (3) Weigh 1.5 g of polyvinyl pyrrolidone into a beaker, add 40 g of pure water and 5 g of polyurethane emulsion and stir evenly, then add to the beaker in step (2) and stir thoroughly to mix evenly; (4) The colloid obtained in step (3) is vacuum degassed, coated on a PET film after degassed, and dried in an oven at 95°C for 8 minutes to obtain a dehydrated high-temperature resistant hydrogel.

2. A method for preparing a dry high-temperature resistant hydrogel, characterized in that: Prepared by the following method: (1) Weigh 5.0 g of sodium polyacrylate, 0.1 g of disodium EDTA, 1.2 g of aluminum chloride, and 0.8 g of aluminum oxide into a beaker, add 20.0 g of polyethylene glycol-400, stir well, and set aside; (2) Measure 12 ml of 5% hydrochloric acid solution and add it to the beaker in step (1), stirring thoroughly to make it uniform; (3) Weigh 2.5 g of sodium carboxymethyl cellulose into a beaker, add 80 g of pure water and stir evenly, then add it to the beaker in step (2) and stir thoroughly to mix evenly; (4) The colloid obtained in step (3) is vacuum degassed, coated on a PET film after degassed, and baked in an oven at 120°C for 3 minutes to obtain a dehydrated high-temperature resistant hydrogel.

3. A dry high-temperature resistant hydrogel prepared by the preparation method according to any one of claims 1 to 2.

4. Use of the dry high-temperature resistant hydrogel according to claim 3 in preparing a medical dressing matrix material, a facial mask matrix material or a water-absorbing material.

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