Moisturizing microemulsion as well as preparation method and application thereof in supercritical modification

Abstract

The invention discloses a moisturizing microemulsion, a preparation method thereof and application of the moisturizing microemulsion in supercritical modification, and belongs to the technical field of dyeing and finishing. A modified small molecule oily moisturizing agent and hyperbranched polyglycerol fatty acid ester are compounded to prepare a compound emulsifier with a stable solubilizing effect; under the action of sugar alcohol, the moisturizing microemulsion which has a good solubilizing effect on a macromolecular water-based moisturizing agent in a supercritical system is obtained; the moisturizing microemulsion is used for carrying out supercritical modification treatment on fibers, and the obtained fibers are loaded with a micromolecular oily moisturizer and a macromolecular aqueous moisturizer at the same time, so that the moisturizing microemulsion has a very good moisturizing effect.

Description

Technical Field

[0001] This invention belongs to the field of dyeing and finishing technology, specifically relating to a moisturizing microemulsion, its preparation method, and its application in supercritical modification. Background Technology

[0002] Cellulose fiber, as a natural material, occupies a core position in the global textile market due to its natural breathability, moisture absorption, and skin-friendliness. China accounts for a significant portion of global cellulose fiber consumption, with its products widely used in clothing, home textiles, and medical fields. With the rise of skincare textiles, consumer demand for moisturizing functions has increased significantly. Market research shows that textiles with added moisturizing ingredients such as camellia oil, hyaluronic acid, and collagen are highly favored for their ability to maintain skin hydration. For moisturizing modification techniques on cellulose fibers, there are methods such as impregnation or padding followed by drying to load moisturizing active ingredients onto the fibers, and pre-treatment followed by grafting of active ingredients onto the fibers. The finishing methods described above suffer from issues such as easy loss or uneven penetration of ingredients, while grafting carries the risk of damaging the fiber's mechanical properties and feel.

[0003] Supercritical carbon dioxide modification technology utilizes the high diffusivity and solubility of supercritical fluids to swell fibers under certain temperature and pressure. Functional molecules penetrate into the fiber interior during supercritical fluid circulation and are fixed after pressure release, achieving uniform modification of the fiber's internal and external structure. Compared with post-treatment, the wash resistance of functional substances is greatly improved, while avoiding the damage to the cotton fiber structure caused by chemical grafting and preserving its original properties. Chinese patent CN108914599A discloses a processing method for imbuing cellulose fibers with moisturizing functions based on supercritical CO2 fluid technology. Small molecule moisturizers such as epigallocatechin gallate are loaded into cellulose fibers through supercritical carbon dioxide microemulsion. Carbon dioxide is a non-polar substance with good solubility for small molecule oily substances, but poor solubility for hydrophilic substances. For polar substances, supercritical carbon dioxide is used as the continuous phase, and a water-in-oil microemulsion is prepared through the action of surfactants to encapsulate the polar active ingredients, achieving their dissolution in supercritical carbon dioxide. However, supercritical carbon dioxide water-in-oil microemulsions have low water content and small microemulsion micelle volume, making it impossible to encapsulate large amounts of polar active substances, especially large polar molecules, in the microemulsion. Summary of the Invention

[0004] Technical problem to be solved: In view of the existing technology, the post-processing method has the problem of easy loss of components or uneven penetration, while the grafting method has the risk of damaging the mechanical properties and hand feel of the fiber. The supercritical carbon dioxide oil-in-water microemulsion has low water content and small microemulsion micelle volume, which makes it impossible to encapsulate a large amount of polar active materials, especially large polar molecules, in the microemulsion. This application provides a moisturizing microemulsion, its preparation method and its application in supercritical modification.

[0005] Objectives of the Invention: One objective of this invention is to provide a moisturizing microemulsion and its preparation method. A small-molecule oily moisturizer is modified using a specific ratio of ethylene oxide and propylene oxide, and simultaneously compounded with hyperbranched polyglycerol fatty acid esters to obtain a composite emulsifier with stable solubilizing effect in a supercritical carbon dioxide system. Furthermore, the addition of sugar alcohols improves the microemulsion micelle volume and water core polarity, resulting in a moisturizing microemulsion with excellent solubilizing effect on macromolecular aqueous moisturizers in a supercritical carbon dioxide system. Another objective of this invention is to provide the application of the above-mentioned moisturizing microemulsion in supercritical modification, achieving simultaneous loading of small-molecule oily moisturizers and macromolecular aqueous moisturizers in cellulose fibers within a supercritical carbon dioxide system.

[0006] The specific technical solution is as follows:

[0007] A moisturizing microemulsion, comprising, by weight parts, 5-10 parts of modified small molecule oily moisturizer, 1-5 parts of hyperbranched polyglycerol fatty acid ester, 1-3 parts of sugar alcohol, 1-3 parts of deionized water and 0.1-0.5 parts of macromolecule aqueous moisturizer.

[0008] Furthermore, the modified small-molecule oily moisturizer is obtained by modifying natural oils containing fatty acid glycerides with ethylene oxide and propylene oxide. The specific preparation method is as follows:

[0009] Weigh out natural oils and mix them with Al-Mg composite catalyst. Add ethylene oxide and propylene oxide under vacuum conditions to react. The mass ratio of natural oils, ethylene oxide and propylene oxide is (10-20):1:(2-5), and the mass ratio of Al-Mg composite catalyst to natural oil is 0.1-0.5%. The reaction temperature is 90-130℃ and the reaction time is 60-120 min.

[0010] Furthermore, the natural oil is one or more of the following: camellia oil, olive oil, rosehip oil, shea butter, argan oil, nut oil, coconut oil, and meadowfoam seed oil.

[0011] Furthermore, the preparation method of the hyperbranched polyglycerol fatty acid ester is as follows:

[0012] S1: Weigh 1-2 parts of glycidol and 10 parts of polyglycerol according to the mass ratio, and react them at 100-130℃ for 1-3 hours under the catalysis of 0.05-0.1 parts of sodium hydroxide to obtain hyperbranched polyglycerol;

[0013] S2: Weigh 3-6 parts of fatty acids and 10 parts of hyperbranched polyglycerol and dissolve them in 100 parts of methanol. Under the catalysis of 0.1-0.5 parts of sodium methoxide, react at 60-90℃ for 1-2 hours to obtain hyperbranched polyglycerol fatty acid esters.

[0014] Furthermore, the degree of polymerization of the polyglycerol is 3-6, the HLB value of the hyperbranched polyglycerol fatty acid ester is 4-6, and the fatty acid is one or more of stearic acid, palmitic acid, myristic acid, lauric acid, and oleic acid.

[0015] Furthermore, the sugar alcohol is one or more of sorbitol, xylitol, maltitol, and erythritol.

[0016] Furthermore, the macromolecular aqueous moisturizer is one or more of hyaluronic acid, chitosan, aloe polysaccharide, and seaweed polysaccharide, with a molecular weight of 50,000 to 200,000 Daltons.

[0017] A method for preparing a moisturizing microemulsion includes the following steps:

[0018] Step 1: Prepare a composite emulsifier by mixing a modified small molecule oily moisturizer and a hyperbranched polyglycerol fatty acid ester.

[0019] Step 2: Add sugar alcohol and macromolecular water-based moisturizer to deionized water to prepare an aqueous solution;

[0020] Step 3: Mix the composite emulsifier and aqueous solution to obtain a moisturizing microemulsion.

[0021] This application also discloses the application of a moisturizing microemulsion in supercritical modification, the specific application steps of which are as follows:

[0022] Step 1: Add the moisturizing microemulsion to the bottom tank of the supercritical fluid processing equipment, and place the fibers to be processed on top of the bottom tank;

[0023] Step 2: Carbon dioxide is introduced into the supercritical equipment and converted into supercritical carbon dioxide fluid at a treatment temperature of 60-100℃ and a treatment pressure of 15-25MPa.

[0024] Step 3: The moisturizing microemulsion is dissolved in supercritical carbon dioxide fluid to obtain a supercritical microemulsion with moisturizing function. The fiber is circulated according to the amount of moisturizing microemulsion added to the fiber at 10-20%, the treatment time is 60-120 minutes, and the treatment bath ratio is 1:10-20 to obtain moisturizing fiber loaded with small molecule oily moisturizer and large molecule watery moisturizer.

[0025] Furthermore, the fiber is one or more of cotton fiber, linen fiber, viscose fiber, lyocell fiber, and modal fiber.

[0026] The present invention has the following beneficial effects:

[0027] (1) In this invention, the composite emulsifier obtained by combining modified small molecule oily moisturizer with hyperbranched polyglycerol fatty acid ester has good stability and solubility in supercritical carbon dioxide water-in-oil microemulsion. Under the modification of ethylene oxide and propylene oxide in a specific ratio, the unique hyperbranched structure forms a high-strength and high-density interfacial film, which can significantly reduce interfacial tension and reduce the cloud point pressure of the system. The large steric hindrance prevents droplet aggregation and can stably form smaller, more uniform, and more numerous water nuclei, significantly increasing the solubility of water in supercritical microemulsion.

[0028] (2) Although the water-in-oil emulsifier obtained by the compounding provided by the present invention can effectively reduce interfacial tension, stabilize interfacial film and solubilize a large number of water molecules, its solubilization ability for macromolecular polar substances is not significantly improved. Furthermore, the sugar alcohol and hyperbranched polyglycerol fatty acid ester form a dense hydrogen bond network at the micelle interface, which reduces the interfacial bending energy, improves the flexibility and extensibility of the micelle network structure, and significantly increases the volume of micelle water cores. At the same time, it enhances the affinity with the polysaccharide chains of macromolecular water-based moisturizers and actively adsorbs macromolecules through electrostatic interaction, thereby greatly improving the solubility of macromolecular water-based moisturizers in supercritical microemulsions.

[0029] (3) The moisturizing microemulsion prepared by the present invention has good stability in the supercritical carbon dioxide system and has a good solubilizing effect on macromolecular water-based moisturizers. When the moisturizing microemulsion of the present invention is used to perform supercritical modification treatment on fibers, the resulting fibers are simultaneously loaded with small molecule oil-based moisturizers and macromolecular water-based moisturizers, and have a good moisturizing effect. Detailed Implementation

[0030] The preferred embodiments of the present invention will now be described in detail with reference to specific examples. It should be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from its spirit and essence.

[0031] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0032] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0033] Example 1

[0034] A method for preparing a moisturizing microemulsion includes the following steps:

[0035] Step 1: Weigh 20 parts of camellia oil and 0.1 parts of Al-Mg composite catalyst and mix them. Under vacuum conditions, add 1 part of ethylene oxide and 5 parts of propylene oxide and react for 120 min at a reaction temperature of 130℃ to obtain a modified small molecule oily moisturizer.

[0036] One part of glycidol and 10 parts of polyglycerol with a degree of polymerization of 3 were weighed and reacted at 100°C for 3 hours under the catalysis of 0.05 parts of sodium hydroxide to obtain hyperbranched polyglycerol; three parts of oleic acid and 10 parts of hyperbranched polyglycerol were weighed and dissolved in 100 parts of methanol and reacted at 60°C for 2 hours under the catalysis of 0.1 parts of sodium methoxide to obtain hyperbranched polyglycerol oleate with an HLB value of 6.

[0037] A composite emulsifier was prepared by mixing 5 parts of modified small molecule oily moisturizer and 1 part of hyperbranched polyglycerol oleate.

[0038] Step 2: Add 1 part sorbitol and 0.1 part hyaluronic acid with a molecular weight of 5w Daltons to 1 part deionized water to prepare an aqueous solution;

[0039] Step 3: Mix the composite emulsifier and aqueous solution to obtain a moisturizing microemulsion.

[0040] An application of a moisturizing microemulsion in supercritical modification, the specific application steps are as follows:

[0041] Step 1: Add the moisturizing microemulsion to the bottom tank of the supercritical equipment, and place the cotton fibers to be treated on top of the bottom tank;

[0042] Step 2: Carbon dioxide is introduced into the supercritical equipment and converted into supercritical carbon dioxide fluid at a treatment temperature of 60°C and a treatment pressure of 25MPa.

[0043] Step 3: The moisturizing microemulsion is dissolved in supercritical carbon dioxide fluid to obtain a supercritical microemulsion with moisturizing function. The cotton fiber is circulated and treated at a rate of 10% of the amount of moisturizing microemulsion added to the fiber for 120 minutes at a treatment bath ratio of 1:20 to obtain cotton fiber loaded with small molecule oily moisturizer modified camellia oil and large molecule watery moisturizer hyaluronic acid.

[0044] Example 2

[0045] A method for preparing a moisturizing microemulsion includes the following steps:

[0046] Step 1: Weigh 10 parts of olive oil and 0.01 parts of Al-Mg composite catalyst and mix them. Under vacuum conditions, add 1 part of ethylene oxide and 2 parts of propylene oxide and react for 60 min at a reaction temperature of 90℃ to obtain a modified small molecule oily moisturizer.

[0047] Two parts of glycidol and ten parts of polyglycerol with a degree of polymerization of 6 were weighed and reacted at 130°C for 1 h under the catalysis of 0.1 parts of sodium hydroxide to obtain hyperbranched polyglycerol; six parts of stearic acid and ten parts of hyperbranched polyglycerol were weighed and dissolved in 100 parts of methanol and reacted at 90°C for 1 h under the catalysis of 0.5 parts of sodium methoxide to obtain hyperbranched polyglycerol stearate with an HLB value of 4.

[0048] A composite emulsifier was prepared by mixing 10 parts of modified small molecule oily moisturizer and 5 parts of hyperbranched polyglycerol stearate.

[0049] Step 2: Add 3 parts of sorbitol and 0.5 parts of chitosan with a molecular weight of 20w Daltons to 3 parts of deionized water to prepare an aqueous solution;

[0050] Step 3: Mix the composite emulsifier and aqueous solution to obtain a moisturizing microemulsion.

[0051] An application of a moisturizing microemulsion in supercritical modification, the specific application steps are as follows:

[0052] Step 1: Add the moisturizing microemulsion to the bottom tank of the supercritical equipment, and place the viscose fiber to be treated on top of the bottom tank;

[0053] Step 2: Carbon dioxide is introduced into the supercritical equipment and converted into supercritical carbon dioxide fluid at a treatment temperature of 100℃ and a treatment pressure of 15MPa.

[0054] Step 3: The moisturizing microemulsion is dissolved in supercritical carbon dioxide fluid to obtain a supercritical microemulsion with moisturizing function. The viscose fiber is circulated and treated at a concentration of 20% of the moisturizing microemulsion for 60 minutes at a treatment bath ratio of 1:10 to obtain viscose fiber loaded with modified olive oil, a small molecule oily moisturizer, and chitosan, a large molecule watery moisturizer.

[0055] Example 3

[0056] A method for preparing a moisturizing microemulsion includes the following steps:

[0057] Step 1: Weigh 15 parts of meadowfoam seed oil and 0.05 parts of Al-Mg composite catalyst and mix them. Under vacuum conditions, add 1 part of ethylene oxide and 3.5 parts of propylene oxide and react for 90 min at a reaction temperature of 110℃ to obtain a modified small molecule oily moisturizer.

[0058] 1.5 parts of glycidol and 10 parts of polyglycerol with a degree of polymerization of 5 were weighed and reacted at 110°C for 2 hours under the catalysis of 0.07 parts of sodium hydroxide to obtain hyperbranched polyglycerol; 5 parts of lauric acid and 10 parts of hyperbranched polyglycerol were weighed and dissolved in 100 parts of methanol and reacted at 75°C for 1 hour under the catalysis of 0.3 parts of sodium methoxide to obtain hyperbranched polyglycerol laurate with an HLB value of 5.

[0059] A composite emulsifier was prepared by mixing 8 parts of modified small molecule oily moisturizer and 3 parts of hyperbranched polyglycerol laurate.

[0060] Step 2: Add 2 parts erythritol and 0.4 parts aloe polysaccharide with a molecular weight of 10w Daltons to 2 parts deionized water to prepare an aqueous solution;

[0061] Step 3: Mix the composite emulsifier and aqueous solution to obtain a moisturizing microemulsion.

[0062] An application of a moisturizing microemulsion in supercritical modification, the specific application steps are as follows:

[0063] Step 1: Add the moisturizing microemulsion to the bottom tank of the supercritical fluid processing equipment, and place the Lyocell fibers to be processed on top of the bottom tank;

[0064] Step 2: Carbon dioxide is introduced into the supercritical equipment and converted into supercritical carbon dioxide fluid at a treatment temperature of 80℃ and a treatment pressure of 20MPa.

[0065] Step 3: The moisturizing microemulsion is dissolved in supercritical carbon dioxide fluid to obtain a supercritical microemulsion with moisturizing function. Lyocell fiber is circulated and treated at a concentration of 15% of the moisturizing microemulsion for 90 minutes at a treatment bath ratio of 1:15 to obtain Lyocell fiber loaded with modified meadowfoam seed oil, a small molecule oily moisturizer, and aloe polysaccharide, a large molecule watery moisturizer.

[0066] Example 4

[0067] A method for preparing a moisturizing microemulsion includes the following steps:

[0068] Step 1: Weigh 20 parts of rosehip oil and 0.1 parts of Al-Mg composite catalyst and mix them. Under vacuum conditions, add 1 part of ethylene oxide and 5 parts of propylene oxide and react for 120 min at a reaction temperature of 130℃ to obtain a modified small molecule oily moisturizer.

[0069] One part of glycidol and 10 parts of polyglycerol with a degree of polymerization of 3 were weighed and reacted at 100°C for 3 hours under the catalysis of 0.05 parts of sodium hydroxide to obtain hyperbranched polyglycerol; three parts of palmitic acid and 10 parts of hyperbranched polyglycerol were weighed and dissolved in 100 parts of methanol and reacted at 60°C for 2 hours under the catalysis of 0.1 parts of sodium methoxide to obtain hyperbranched polyglycerol palmitate with an HLB value of 6.

[0070] A composite emulsifier was prepared by mixing 5 parts of modified small molecule oily moisturizer and 1 part of hyperbranched polyglycerol palmitate.

[0071] Step 2: Add 1 part maltitol and 0.1 part seaweed polysaccharide with a molecular weight of 5w Daltons to 1 part deionized water to prepare an aqueous solution;

[0072] Step 3: Mix the composite emulsifier and aqueous solution to obtain a moisturizing microemulsion.

[0073] An application of a moisturizing microemulsion in supercritical modification, the specific application steps are as follows:

[0074] Step 1: Add the moisturizing microemulsion to the bottom tank of the supercritical fluid processing equipment, and place the hemp fibers to be processed on top of the bottom tank;

[0075] Step 2: Carbon dioxide is introduced into the supercritical equipment and converted into supercritical carbon dioxide fluid at a treatment temperature of 60°C and a treatment pressure of 25MPa.

[0076] Step 3: The moisturizing microemulsion is dissolved in supercritical carbon dioxide fluid to obtain a supercritical microemulsion with moisturizing function. The hemp fiber is circulated and treated at a rate of 10% of the amount of moisturizing microemulsion added to the hemp fiber for 120 minutes at a treatment bath ratio of 1:20 to obtain hemp fiber loaded with small molecule oily moisturizer modified rosehip oil and large molecule watery moisturizer seaweed polysaccharide.

[0077] Example 5

[0078] A method for preparing a moisturizing microemulsion includes the following steps:

[0079] Step 1: Weigh 20 parts of coconut oil and 0.1 parts of Al-Mg composite catalyst and mix them. Under vacuum conditions, add 1 part of ethylene oxide and 5 parts of propylene oxide and react for 120 min at a reaction temperature of 130℃ to obtain a modified small molecule oily moisturizer.

[0080] One part of glycidol and 10 parts of polyglycerol with a degree of polymerization of 3 were weighed and reacted at 100°C for 3 hours under the catalysis of 0.05 parts of sodium hydroxide to obtain hyperbranched polyglycerol; three parts of palmitic acid and 10 parts of hyperbranched polyglycerol were weighed and dissolved in 100 parts of methanol and reacted at 60°C for 2 hours under the catalysis of 0.1 parts of sodium methoxide to obtain hyperbranched polyglycerol myristate with an HLB value of 6.

[0081] A composite emulsifier was prepared by mixing 5 parts of modified small molecule oily moisturizer and 1 part of hyperbranched polyglycerol myristate.

[0082] Step 2: Add 1 part sorbitol and 0.1 part chitosan with a molecular weight of 5 w Daltons to 1 part deionized water to prepare an aqueous solution;

[0083] Step 3: Mix the composite emulsifier and aqueous solution to obtain a moisturizing microemulsion.

[0084] An application of a moisturizing microemulsion in supercritical modification, the specific application steps are as follows:

[0085] Step 1: Add the moisturizing microemulsion to the bottom tank of the supercritical equipment, and place the modal fibers to be treated on top of the bottom tank;

[0086] Step 2: Carbon dioxide is introduced into the supercritical equipment and converted into supercritical carbon dioxide fluid at a treatment temperature of 60°C and a treatment pressure of 25MPa.

[0087] Step 3: The moisturizing microemulsion is dissolved in supercritical carbon dioxide fluid to obtain a supercritical microemulsion with moisturizing function. Modal fiber is circulated and treated with the moisturizing microemulsion at a ratio of 10% for 120 minutes and a treatment bath ratio of 1:20 to obtain Modal fiber loaded with small molecule oily moisturizer modified coconut oil and large molecule watery moisturizer chitosan.

[0088] The moisturizing microemulsions prepared in Examples 1-5 exhibit good stability in a supercritical carbon dioxide system and demonstrate excellent solubilizing effects on macromolecular aqueous moisturizers. Fibers treated with these moisturizing microemulsions via supercritical loading simultaneously contain both small-molecule oil-based moisturizers and macromolecular aqueous moisturizers, resulting in superior moisturizing effects.

[0089] Comparative Example 1

[0090] Compared with Example 1, in the preparation method of the modified small molecule oily moisturizer, 2 parts of ethylene oxide and 5 parts of propylene oxide are added under vacuum conditions.

[0091] The modified small molecule oily moisturizer has a large proportion of ethylene oxide and excessively long hydrophilic segments, resulting in a high cloud point pressure of the moisturizing microemulsion in supercritical carbon dioxide and generally poor microemulsion stability.

[0092] Comparative Example 2

[0093] Compared with Example 1, in the preparation method of the modified small molecule oily moisturizer, 1 part of ethylene oxide and 6 parts of propylene oxide are added under vacuum conditions.

[0094] The modified small-molecule oily moisturizer has a high proportion of propylene oxide and excessively long hydrophobic segments. This results in a lower cloud point pressure and improved stability of the resulting moisturizing microemulsion in supercritical carbon dioxide, but also a decreased solubilizing ability, making it unsuitable for storing large quantities of large-molecule water-based moisturizers. The moisturizing effect of cotton fibers treated with this supercritical moisturizing microemulsion is generally poor.

[0095] Comparative Example 3

[0096] Compared to Example 1, the moisturizing microemulsion does not contain hyperbranched polyglycerol oleate.

[0097] Relying solely on the surface-active effects of modified small-molecule oily moisturizers cannot significantly reduce interfacial tension in supercritical systems, resulting in poor microemulsion stability and unsatisfactory solubilization properties. The moisturizing effect on cotton fibers treated with supercritical microemulsions is generally mediocre. Composite emulsifiers containing hyperbranched structures form high-strength, high-density interfacial films in supercritical systems, significantly reducing interfacial tension. Their greater steric hindrance prevents droplet aggregation, stably forming smaller, more uniform, and more numerous water nuclei, significantly increasing the solubility of water in supercritical microemulsions and creating conditions for further dissolution of large-molecule water-based moisturizers.

[0098] Comparative Example 4

[0099] Compared with Example 1, a composite emulsifier was obtained by compounding polyglycerol oleate.

[0100] Because polyglycerol oleate lacks a hyperbranched structure, its synergistic effect with modified small-molecule oily moisturizers is less significant than that of hyperbranched polyglycerol oleate. The resulting moisturizing microemulsion exhibits higher interfacial tension in supercritical systems, resulting in lower interfacial film strength, relatively larger or uneven microemulsion droplets, and poorer stability. The hydroxyl density and accessibility of polyglycerol fatty acid esters are lower than those of hyperbranched structures, leading to poorer solubilization properties of the moisturizing microemulsion in supercritical systems. The moisturizing effect of cotton fibers treated with supercritical moisturizing microemulsions is generally poor.

[0101] Comparative Example 5

[0102] Compared with Example 1, a composite emulsifier was obtained by compounding hyperbranched Jimiqi surfactant.

[0103] Compared to other hyperbranched surfactants, hyperbranched polyglycerol fatty acid esters share a similar glycerol backbone and fatty acid segments with modified small-molecule oily moisturizers, exhibiting good molecular compatibility and promoting interfacial co-adsorption. While hyperbranched Gimitch surfactants possess a hyperbranched structure, their poor compatibility after compounding leads to a loose interfacial molecular arrangement, preventing the full realization of the special effects of hyperbranching. Consequently, the resulting moisturizing microemulsions show little improvement in stability and solubilization performance in supercritical systems. The moisturizing effect on cotton fibers treated with supercritical moisturizing microemulsions is generally mediocre.

[0104] Comparative Example 6

[0105] Compared to Example 1, the moisturizing microemulsion does not contain sorbitol, and the interfacial film formed by the composite emulsifier is dense and rigid. While this stabilizes the water cores, it also severely limits their expansion ability. Even with a large number of stable water cores, the excessively small cores cannot accommodate large-molecule aqueous moisturizers. The steric hindrance of the interfacial layer prevents droplet aggregation, but it also makes it difficult for large-molecule aqueous moisturizers to effectively embed or penetrate the dense interfacial layer to reach the water cores. The moisturizing effect of cotton fibers treated with the supercritical modification of the moisturizing microemulsion is generally poor.

[0106] The hydroxyl groups on the surface of sugar alcohols form a dense hydrogen bond network with hyperbranched polyglycerol fatty acid esters at the micelle interface, reducing the interfacial bending energy and improving the flexibility and extensibility of the micelle network structure, thus significantly increasing the volume of the water core in the micelles of the moisturizing microemulsion in the supercritical system. Simultaneously, it enhances the affinity for the polysaccharide chains of macromolecular water-based moisturizers, adsorbing them through electrostatic interactions, thereby greatly improving the solubility of macromolecular water-based moisturizers in the supercritical microemulsion.

[0107] Comparative Example 7

[0108] Replacing sugar alcohols with ethanol or propanol is an option. Compared to sugar alcohols, short-chain alcohols have better solubility in supercritical carbon dioxide and cannot effectively swell water cores, thus having no significant effect on improving the solubility of macromolecular water-based moisturizers in supercritical microemulsions. The moisturizing effect of cotton fibers treated with supercritical moisturizing microemulsions is generally poor.

[0109] Table 1

[0110]

[0111]

[0112] The cloud point pressure of a microemulsion in supercritical carbon dioxide indicates its stability; a lower cloud point pressure indicates better stability. The ratio W0 of the number of soluble water molecules to surfactant molecules in the microemulsion represents the water solubility; a larger W0 indicates a stronger water solubility in the microemulsion. The fiber moisture retention rate R is calculated as follows; a larger R indicates better moisture retention.

[0113] R = (CA) / (BA) × 100%

[0114] Where A represents the dry weight of the fiber, B represents the weight of the fiber after absorbing moisture for 2 hours at 25℃ and 90% relative humidity, and C represents the weight of the fiber after absorbing moisture and releasing moisture for 2 hours at 25℃ and 40% relative humidity.

[0115] Table 1 shows the cloud point pressure and water solubility of the supercritical microemulsion, as well as the content of macromolecular moisturizers and the fiber moisture retention rate after treatment. Table 1 indicates that the moisturizing microemulsions prepared in Examples 1-5 exhibit good stability in the supercritical carbon dioxide system and demonstrate excellent solubilization of macromolecular aqueous moisturizers. The fibers treated with the supercritical moisturizing microemulsion simultaneously contain both small-molecule oil-based moisturizers and macromolecular aqueous moisturizers, resulting in excellent moisturizing effects. In Comparative Examples 1 and 2, excessively long or short hydrophilic segments of the modified small-molecule oil-based moisturizers lead to decreased stability or solubility of the supercritical microemulsion. Comparative Examples 3-5, lacking hyperbranched polyglycerol fatty acid esters or incorporating other types of emulsifiers, result in decreased stability and solubility of the moisturizing microemulsion in the supercritical system, and the moisturizing effect of the fibers treated with the supercritical moisturizing microemulsion is generally poor. Comparative Examples 6 and 7, the absence of sugar alcohols or their replacement with other short-chain alcohols, resulted in a decrease in the solubility of macromolecular water-based moisturizers in supercritical microemulsions. The moisturizing effect of fibers treated with supercritical modification of moisturizing microemulsions was generally poor.

Claims

1. A moisturizing microemulsion, characterized in that, It is composed of 5-10 parts modified small molecule oily moisturizer, 1-5 parts hyperbranched polyglycerol fatty acid ester, 1-3 parts sugar alcohol, 1-3 parts deionized water and 0.1-0.5 parts macromolecule watery moisturizer by weight ratio.

2. The moisturizing microemulsion according to claim 1, characterized in that, The modified small-molecule oily moisturizer is obtained by modifying natural oils containing fatty acid glycerides with ethylene oxide and propylene oxide. The specific preparation method is as follows: Weigh out natural oils and mix them with Al-Mg composite catalyst. Add ethylene oxide and propylene oxide under vacuum conditions to react. The mass ratio of natural oils, ethylene oxide and propylene oxide is (10-20):1:(2-5), and the mass ratio of Al-Mg composite catalyst to natural oil is 0.1-0.5%. The reaction temperature is 90-130℃ and the reaction time is 60-120 min.

3. The moisturizing microemulsion according to claim 2, characterized in that, The natural oils mentioned are one or more of the following: camellia oil, olive oil, rosehip oil, shea butter, argan oil, nut oil, coconut oil, and meadowfoam seed oil.

4. The moisturizing microemulsion according to claim 1, characterized in that, The preparation method of the hyperbranched polyglycerol fatty acid ester is as follows: S1: Weigh 1-2 parts of glycidol and 10 parts of polyglycerol according to the mass ratio, and react them at 100-130℃ for 1-3 hours under the catalysis of 0.05-0.1 parts of sodium hydroxide to obtain hyperbranched polyglycerol; S2: Weigh 3-6 parts of fatty acids and 10 parts of hyperbranched polyglycerol and dissolve them in 100 parts of methanol. Under the catalysis of 0.1-0.5 parts of sodium methoxide, react at 60-90℃ for 1-2 hours to obtain hyperbranched polyglycerol fatty acid esters.

5. The moisturizing microemulsion according to claim 4, characterized in that, The degree of polymerization of the polyglycerol is 3-6, the HLB value of the hyperbranched polyglycerol fatty acid ester is 4-6, and the fatty acid is one or more of stearic acid, palmitic acid, myristic acid, lauric acid, and oleic acid.

6. The moisturizing microemulsion according to claim 1, characterized in that, The sugar alcohol is one or more of sorbitol, xylitol, maltitol, and erythritol.

7. The moisturizing microemulsion according to claim 1, characterized in that, The macromolecular aqueous moisturizer is one or more of hyaluronic acid, chitosan, aloe polysaccharide, and seaweed polysaccharide, with a molecular weight of 50,000-200,000 Daltons.

8. A method for preparing the moisturizing microemulsion according to any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Prepare a composite emulsifier by mixing a modified small molecule oily moisturizer and a hyperbranched polyglycerol fatty acid ester. Step 2: Add sugar alcohol and macromolecular water-based moisturizer to deionized water to prepare an aqueous solution; Step 3: Mix the composite emulsifier and aqueous solution to obtain a moisturizing microemulsion.

9. The application of the moisturizing microemulsion according to any one of claims 1-7 in supercritical modification, characterized in that, The specific application steps are as follows: Step 1: Add the moisturizing microemulsion to the bottom tank of the supercritical fluid processing equipment, and place the fibers to be processed on top of the bottom tank; Step 2: Carbon dioxide is introduced into the supercritical equipment and converted into supercritical carbon dioxide fluid at a treatment temperature of 60-100℃ and a treatment pressure of 15-25MPa. Step 3: The moisturizing microemulsion is dissolved in supercritical carbon dioxide fluid to obtain a supercritical microemulsion with moisturizing function. The fiber is circulated according to the amount of moisturizing microemulsion added to the fiber at 10-20%, the treatment time is 60-120 minutes, and the treatment bath ratio is 1:10-20 to obtain moisturizing fiber loaded with small molecule oily moisturizer and large molecule watery moisturizer.

10. The application of the moisturizing microemulsion according to claim 9 in supercritical modification, characterized in that, The fiber is one or more of cotton fiber, linen fiber, viscose fiber, lyocell fiber, and modal fiber.

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