Black-up cream containing biocompatible polylactic acid and preparation method thereof

Abstract

The invention belongs to the technical field of cosmetics, and particularly relates to a tone-up cream containing biocompatible polylactic acid and a preparation method of the tone-up cream. According to the preparation method disclosed by the invention, emulsification and dissolution of polylactic acid in grease are realized through an alkali modification process, the polylactic acid is prevented from being dissolved by using an organic solvent, and residues of the organic solvent are reduced to the greatest extent. The modified polylactic acid is added into a face cream preparation, no obvious particle frosted feeling exists, and application of the polylactic acid in a common water-oil emulsification system is achieved. By replacing traditional titanium dioxide, silica and mineral powder raw materials, polylactic acid with better biocompatibility is added into a face cream product, facial skin texture filling is achieved, and meanwhile the biocompatibility and safety of powder particles are guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of cosmetics, and particularly relates to a natural face cream containing biocompatible polylactic acid and a preparation method thereof. Background Art

[0002] Polylactic acid (PLA), also known as polylactide, is a biodegradable polymer made from the polymerization of lactic acid. Due to its safety and biocompatibility, it is one of the first biodegradable materials approved by the U.S. Food and Drug Administration (FDA) for biomedical use. In the medical field, it is used to produce surgical sutures, tissue engineering scaffolds, and sustained-release drug systems. Its excellent biocompatibility and degradability enable its safe use and gradual absorption in the human body. Because it degrades without pollution, PLA is also widely used in the production of biodegradable plastic bags, food containers, and other packaging materials. Currently, PLA has been registered as a cosmetic raw material, and PLA will be used in more cosmetic formulations in the future.

[0003] For example, CN117883321A discloses a method for preparing L-polylactic acid microspheres, a raw material for cosmetics. The specific process involves using a freeze grinder to crush L-polylactic acid particles into micron-sized powder, then screening out a powder of a predetermined size, then placing the predetermined L-polylactic acid powder into a self-developed dry spheroidization and shaping device to prepare spherical powder, and finally freeze-drying and sterilizing to obtain L-polylactic acid microspheres for use as a raw material for cosmetics. However, this technical solution mainly uses physical methods for screening, shaping, and finally freeze-drying, resulting in a relatively complex overall process flow.

[0004] CN117700696A discloses a polylactic acid microsphere, a preparation method, and an application thereof. Polyethylene glycol stearate, lactide, and a catalyst are placed in a reactor, melt-mixed, and then subjected to a ring-opening polymerization reaction to prepare a mixture of polylactic acid microspheres and polyethylene glycol stearate. This mixture is placed in water, and after the polyethylene glycol stearate is completely dissolved, the mixture is separated and dried to obtain the polylactic acid microspheres. However, this method involves a ring-opening polymerization reaction, which has complex reaction conditions and requires post-processing to elute the polyethylene glycol stearate, which is prone to solvent residue.

[0005] CN117122580A discloses hollow polylactic acid microspheres, their preparation method, and applications. This method utilizes an emulsified solvent volatilization method to prepare sustained-release microspheres. Specifically, degradable polymers, including polylactic acid and cellulose nanocrystals, serve as carriers for drug-loaded microspheres. The drug is curcumin or a plant essential oil. However, this technical solution uses an organic solvent to dissolve the polylactic acid, which can easily result in residual organic solvent residues, posing an irritation risk in cosmetic applications.

[0006] CN118105312A discloses a rapid emulsifying cleansing oil and its preparation process. The method comprises mixing modified polylactic acid, jojoba oil, an emulsifier, phenoxyethanol, glycerin, and D-panthenol, heating, and then cooling to room temperature to produce the rapid emulsifying cleansing oil. Specifically, the modified polylactic acid preparation method comprises dissolving the polylactic acid in tetrahydrofuran solvent, adding a catalyst to obtain chlorinated polylactic acid, then reacting to obtain amino-modified β-cyclodextrin, and finally precipitating, filtering, and washing to obtain the modified polylactic acid. However, this technical solution uses a large amount of organic solvents, many of which are highly toxic and easily lead to residual solvents.

[0007] It can be seen that when polylactic acid is currently used as a cosmetic raw material, there are still various problems that need to be improved, such as complex preparation process and easy generation of organic solvent residues.

[0008] As a new cosmetic product that has emerged in recent years, natural face cream has been favored by more and more consumers due to its natural, light makeup effect and simple skin care and makeup steps. It is also known as the "lazy face cream". In one bottle, natural face cream combines the functions of both skin care cream and foundation, making it particularly popular among urban white-collar workers. The foundation ingredients of natural face cream are generally titanium dioxide, silica, mineral powder, etc., which play a role in modification and filling. If not cleaned properly, such powder raw materials will easily cause damage to the skin if they remain on the skin for a long time. To solve the above problems, the inventors have researched and developed a new modified polylactic acid to replace conventional foundation raw materials. Taking advantage of its safe biocompatibility and degradability, they have developed a natural face cream product containing biocompatible polylactic acid. Summary of the Invention

[0009] In order to solve the defects and shortcomings in the prior art, the present invention provides a natural cream containing biocompatible polylactic acid and a preparation method thereof.

[0010] The purpose of the present invention can be achieved through the following technical solutions: In a first aspect, the present invention provides a method for preparing a natural face cream containing a biocompatible polymer, the method comprising the following steps: Step 1: Dissolve 0.5-1.5 parts of ammonium acryloyldimethyltaurate / VP copolymer (AVC) or carbomer in 50-90 parts of water, then add 0.1-3 parts of glycerin, 0.1-3 parts of butylene glycol, 0.1-3 parts of propylene glycol, 0.1-3 parts of trehalose, and 1-5 parts of pentylene glycol until completely dissolved to form solution A. Step 2: Dissolve 0.1-3 parts of cetearyl glucoside in 1-5 parts of jojoba seed oil, 0.1-3 parts of white oil, and 0.1-3 parts of hexadecanoic acid, and disperse uniformly at high temperature to form solution B; Step 3: adding 0.3-0.8 parts by weight of alkali-modified polylactic acid to solution B and dissolving it completely; and Step 4: Add solution B to solution A, fill in the remaining water to 100 parts by weight, and then homogenize to obtain a natural cream containing a biocompatible polymer.

[0011] As an optional mode, in the above preparation method, the preparation method comprises the following steps: Step 1: Dissolve 0.5-0.9 parts of AVC or carbomer in 60-80 parts of water, then add 0.5-2 parts of glycerol, 0.5-2 parts of butylene glycol, 0.5-2 parts of propylene glycol, 0.5-2 parts of trehalose, and 2-4 parts of pentanediol until completely dissolved to form solution A. Step 2: Dissolve 0.5-2 parts of cetearyl glucoside in 1-3 parts of jojoba seed oil, 0.5-2 parts of white oil, and 0.5-2 parts of hexadecanoic acid, and disperse uniformly at high temperature to form solution B; Step 3: adding 0.4-0.7 parts by weight of alkali-modified polylactic acid to solution B and dissolving it completely; and Step 4: Add solution B to solution A, fill in the remaining water to 100 parts by weight, and then homogenize to obtain a natural cream containing a biocompatible polymer.

[0012] As an optional manner, in the above preparation method, in step 3, the preparation method of the alkali-modified polylactic acid comprises the following steps: Step 3.1: Dissolve 0.1-0.5 parts of a base in 0.1-3 parts of water by weight to form a solution A; Step 3.2: Add 0.1-2 parts of polylactic acid to 1-5 parts of jojoba seed oil by weight to form solution B; Step 3.3: Add solution A dropwise to solution B under heating and stirring, and heat and stir to form solution C; Step 3.4: Dissolve 0.5-2 parts of citric acid in 0.1-3 parts of water, by weight, to form solution D; Step 3.5: Under room temperature, homogenize and stir solution C, and add solution D dropwise into solution C to form a flocculent gel, thereby obtaining alkali-modified polylactic acid.

[0013] As an optional manner, in the above preparation method, in step 2, the high temperature is 80-85° C.; in step 4, the homogenization condition is centrifugation at 6000-8000 rpm, and the homogenization time is 20-30 seconds.

[0014] As an optional mode, in the above preparation method, the base is selected from sodium hydroxide or potassium hydroxide.

[0015] Preferably, the base is selected from sodium hydroxide.

[0016] As an optional manner, in the above preparation method, in step 3.3, the heating temperature is: 85-95°C; the dropping speed is 0.01-0.1 g / min; and the stirring time is 2-5 hours.

[0017] As an optional manner, in the above preparation method, in step 3.5, the homogenization conditions are centrifugation at 3000-5000 rpm, the homogenization time is 20-30 seconds, and flocculent gel is formed when the solution temperature is close to room temperature.

[0018] As an optional manner, in the above preparation method, the alkali-modified polylactic acid is emulsified and dissolved in oils and fats, avoiding the use of organic solvents to dissolve the polylactic acid.

[0019] In a second aspect, the present invention provides a natural cream prepared by the preparation method described in the first aspect.

[0020] Compared with the prior art, the present invention has the following beneficial effects: (1) Through the alkali modification process, the emulsification and dissolution of polylactic acid in oils and fats is achieved, avoiding the use of organic solvents to dissolve polylactic acid and minimizing the residual organic solvents, especially in the formulation of cosmetic preparations, thus reducing the possible negative effects from the source.

[0021] (2) When the modified polylactic acid is added to the cream preparation, there is no obvious granular scrub feeling, which realizes the application of polylactic acid in ordinary water-oil emulsion system. In comparison, if the unmodified polylactic acid is directly added to the emulsion system, the granular feeling is obvious and cannot meet the skin feel requirements of cosmetics.

[0022] (3) Since polylactic acid is green and natural in origin and has no risk of metabolism in the human body, it is a material with good biocompatibility and safety. By replacing traditional raw materials such as titanium dioxide, silica, and mineral powder, it is added to facial cream products to achieve facial skin texture filling while ensuring the biocompatibility and safety of the powder particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 : Infrared spectrum of unmodified polylactic acid.

[0024] Figure 2 : Infrared spectrum of modified polylactic acid.

[0025] Figure 3 : Microscopic observation results of the prepared plain cream sample. The magnification is 200 times. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0027] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased through regular channels.

[0028] The experimental methods in the following examples are conventional methods unless otherwise specified. The experimental materials used in the following examples are commercially available products unless otherwise specified.

[0029] Example 1: Sodium hydroxide modified polylactic acid process (1) Dissolve 0.2 g of sodium hydroxide in 1 g of water to form solution A; (2) Add 0.5 g of polylactic acid to 4 g of jojoba seed oil to form solution B; (3) Under heating and stirring conditions at 90°C, solution A was added dropwise to solution B at a rate of 0.05 g / min, and heated and stirred for 4 hours to form solution C; (4) Dissolve 0.1 g of citric acid in 0.5 g of water to form solution D; (5) Under room temperature conditions, solution C was homogenized and stirred at 4000 rpm for 20 seconds, and solution D was added dropwise to solution C. When the solution temperature was close to room temperature, a flocculent gel was formed, and the preparation was completed.

[0030] like Figure 1 and Figure 2 As shown in , 3500 cm -1 -3700 cm -1 The characteristic peak at 2722-3240 cm is the stretching vibration peak of -OH in polylactic acid, which is the main skeleton peak of polylactic acid; -1 The absorption peak at 1625-1920 cm is the stretching vibration peak of CH in PLA non-aromatic compounds; -1 The peak at 400-850 cm represents the stretching vibration of C=O in PLA; -1 The absorption peak at 400-850 cm is the aromatic CH stretching vibration peak. -1 The absorption peak at 557 cm -1 and 697 cm -1 The peaks appear at the two ends, which are the characteristics of the aromatic CH stretching vibration peaks after modification.

[0031] Based on the PLA synthesis pathway and molecular structure analysis, the first step is to generate a cyclic dimer lactide from lactic acid, which is then ring-opened and polycondensed into PLA. Modification of the PLA with sodium hydroxide facilitates the ring-opening of the polylactic acid during the reaction, exposing more aromatic CH stretch peaks. This also allows for more carbonyl groups to be emulsified and dissolved in oils, making it possible to incorporate PLA into tanning cream formulations.

[0032] Comparative Example 1: Sodium hydroxide modified polylactic acid process - sodium hydroxide content exploration (1) Dissolve 0.1 g of sodium hydroxide in 1 g of water to form solution A; (2) Add 0.5 g of polylactic acid to 4 g of jojoba seed oil to form solution B; (3) Under heating and stirring conditions at 90°C, solution A was added dropwise to solution B at a rate of 0.05 g / min, and heated and stirred for 4 hours to form solution C; (4) Dissolve 0.1 g of citric acid in 0.5 g of water to form solution D; (5) Under room temperature conditions, solution C was homogenized and stirred at 4000 rpm for 20 seconds, and solution D was added dropwise to solution C. When the solution temperature was close to room temperature, a flocculent gel was formed, and the preparation was completed.

[0033] Comparative Example 2: Sodium hydroxide modified polylactic acid process - polylactic acid content exploration (1) Dissolve 0.2 g of sodium hydroxide in 1 g of water to form solution A; (2) Add 1 g of polylactic acid to 4 g of jojoba seed oil to form solution B; (3) Under heating and stirring conditions at 90°C, solution A was added dropwise to solution B at a dropwise rate of 0.05 g / min, and heated and stirred for 4 hours to form solution C; (4) Dissolve 0.1 g of citric acid in 0.5 g of water to form solution D; (5) Under room temperature conditions, solution C was homogenized and stirred at 4000 rpm for 20 seconds, and solution D was added dropwise to solution C. When the solution temperature was close to room temperature, a flocculent gel was formed, and the preparation was completed.

[0034] Comparative Example 3: Sodium hydroxide modified polylactic acid process - reaction conditions exploration (1) Dissolve 0.2 g of sodium hydroxide in 1 g of water to form solution A; (2) Add 0.5 g of polylactic acid to 4 g of jojoba seed oil to form solution B; (3) Directly add solution A to solution B under heating and stirring conditions at 60°C, and heat and stir for 4 hours to form solution C; (4) Dissolve 0.1 g of citric acid in 0.5 g of water to form solution D; (5) Under room temperature conditions, solution C was homogenized and stirred at 4000 rpm for 20 seconds, and solution D was added dropwise to solution C. When the solution temperature was close to room temperature, a flocculent gel was formed, and the preparation was completed.

[0035] Comparative Example 4: Sodium hydroxide modified polylactic acid process - whether citric acid is added (1) Dissolve 0.2 g of sodium hydroxide in 1 g of water to form solution A; (2) Add 0.5 g of polylactic acid to 4 g of jojoba seed oil to form solution B; (3) Under heating and stirring conditions at 90°C, solution A was added dropwise to solution B at a dropwise rate of 0.05 g / min, and heated and stirred for 4 hours to form solution C; (4) Under normal temperature conditions, solution C was homogenized and stirred at 4000 rpm for 20 seconds. When the solution temperature was close to normal temperature and formed a flocculent gel, the preparation was completed.

[0036] Example 2: Preparation process of modified polylactic acid-containing natural cream Preparation process of tanning cream: (1) Take 70 g of water, dissolve 0.8 g of AVC first, then add 1 g of glycerol, 1 g of butylene glycol, 1 g of propylene glycol, 1 g of trehalose, and 3 g of pentanediol until completely dissolved to form solution A; (2) Dissolve 1 gram of cetearyl glucoside in 2 grams of jojoba seed oil, 1 gram of white oil, and 1 gram of hexadecanoic acid, and disperse evenly at 85°C to form solution B; (3) 0.5 g of the modified polylactic acid prepared in Example 1 (Comparative Example 1, Comparative Example 2, Comparative Example 3 or Comparative Example 4) and conventional commercially available polylactic acid were added to solution B and dissolved completely; (4) Solution B was added to solution A, and the remaining water was added to 100 g. The mixture was homogenized at 8000 rpm for 20 seconds to form a cream sample, i.e., a plain cream containing modified polylactic acid.

[0037] The prepared plain cream samples were subjected to skin feel test and microscopic observation, and the results are shown in Table 1 and Table 2. Figure 3 shown.

[0038] Table 1: Skin feel test results of natural cream samples containing polylactic acid The performance test results of the plain cream sample obtained in Example 2 are shown in Table 2 below.

[0039] Table 2: Performance test results of natural cream samples containing polylactic acid It can be seen from the data in Table 2 above that the plain cream sample containing polylactic acid prepared in Example 2 has a uniform and stable appearance and remains stable under high and low temperature conditions without any stratification, demulsification, etc. The pH value is neutral, which meets the relevant standards of the cosmetics industry.

[0040] Example 3: Comparison of glossiness of facial wrinkles between PLA-containing cream and ordinary cream Reference Example 2 Preparation process of the plain cream was used to prepare a common facial cream.

[0041] Ordinary face cream preparation process: (1) Take 70 g of aqueous solution, dissolve 0.8 g of AVC first, then add 1 g of glycerol, 1 g of butylene glycol, 1 g of propylene glycol, 1 g of trehalose, and 3 g of pentanediol until completely dissolved to form solution A; (2) Dissolve 1 gram of cetearyl glucoside in 2 grams of jojoba seed oil, 1 gram of white oil, 1 gram of hexadecanoic acid, and 4 grams of jojoba seed oil, and disperse evenly at 85°C to form solution B; (3) Solution B was added to solution A, and the remaining water was added to 100 g. The mixture was homogenized at 8000 rpm for 20 seconds to form a cream sample, i.e., a normal face cream sample.

[0042] Individual typology angle (ITA) values ​​are based on L a b) Skin color measurement indicators established in the color space. The ITA value quantifies skin color and is an important indicator for objectively evaluating skin roughness. A larger ITA value indicates a brighter skin color, higher skin gloss, and therefore lower roughness. The cream samples prepared in Examples 2 and 3 above were tested on five subjects for short-term wrinkle reduction.

[0043] After the subjects cleaned their faces with clean water and wiped them clean, they sat in a room for 20 minutes. Initial values ​​were tested on the skin at the corners of each subject's face and recorded. Then, soybean-sized amounts of the samples of Example 2 and Example 3 were applied to the left and right corners of the eyes of the five subjects, with Example 2 applied to the left corner of the eye and Example 3 applied to the right corner of the eye. After sitting in a room for 60 minutes, ITA values ​​were again tested on the skin at the corners of the eyes on both sides of the subjects' faces. The trial results are summarized in Table 3 below: Table 3: Subject ITA value feedback form It can be seen from the ITA value feedback table of the subjects that the skin at the left corner of the eye was smeared with the bare face cream sample prepared in Example 2, and the polylactic acid filled the wrinkles on the skin at the corner of the eye, achieving the effect of instant wrinkle removal. At the same time, since the skin texture was effectively filled, the roughness was significantly reduced, the skin glossiness changed significantly, and the ITA value was significantly improved; while the skin at the right corner of the eye was smeared with the cream sample prepared in Example 3, and judging from the change in ITA value, there was only a small range of improvement. It should be that the oil and moisturizing ingredients in the cream temporarily played a role in improving the skin glossiness. Whether the addition of polylactic acid has a significant effect on filling skin wrinkles.

[0044] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for preparing a natural face cream containing a biocompatible polymer, characterized in that: The preparation method comprises the following steps: Step 1: Dissolve 0.5-1.5 parts of ammonium acryloyldimethyltaurate / VP copolymer (AVC) or carbomer in 50-90 parts of water, then add 0.1-3 parts of glycerin, 0.1-3 parts of butylene glycol, 0.1-3 parts of propylene glycol, 0.1-3 parts of trehalose, and 1-5 parts of pentylene glycol until completely dissolved to form solution A. Step 2: Dissolve 0.1-3 parts of cetearyl glucoside in 1-5 parts of jojoba seed oil, 0.1-3 parts of white oil, and 0.1-3 parts of hexadecanoic acid, and disperse uniformly at high temperature to form solution B; Step 3: adding 0.3-0.8 parts by weight of alkali-modified polylactic acid to solution B and dissolving it completely; and Step 4: Add solution B to solution A, fill in the remaining water to 100 parts by weight, and then homogenize to obtain a natural cream containing a biocompatible polymer.

2. The method for preparing the natural cream according to claim 1, wherein: The preparation method comprises the following steps: Step 1: Dissolve 0.5-0.9 parts of AVC or carbomer in 60-80 parts of water, then add 0.5-2 parts of glycerol, 0.5-2 parts of butylene glycol, 0.5-2 parts of propylene glycol, 0.5-2 parts of trehalose, and 2-4 parts of pentanediol until completely dissolved to form solution A. Step 2: Dissolve 0.5-2 parts of cetearyl glucoside in 1-3 parts of jojoba seed oil, 0.5-2 parts of white oil, and 0.5-2 parts of hexadecanoic acid, and disperse uniformly at high temperature to form solution B; Step 3: adding 0.4-0.7 parts by weight of alkali-modified polylactic acid to solution B and dissolving it completely; and Step 4: Add solution B to solution A, fill in the remaining water to 100 parts by weight, and then homogenize to obtain a natural cream containing a biocompatible polymer.

3. The method for preparing the natural cream according to claim 1, wherein: In step 3, the preparation method of the alkali-modified polylactic acid comprises the following steps: Step 3.1: Dissolve 0.1-0.5 parts of a base in 0.1-3 parts of water by weight to form a solution A; Step 3.2: Add 0.1-2 parts of polylactic acid to 1-5 parts of jojoba seed oil by weight to form solution B; Step 3.3: Add solution A dropwise to solution B under heating and stirring, and heat and stir to form solution C; Step 3.4: Dissolve 0.5-2 parts of citric acid in 0.1-3 parts of water, by weight, to form solution D; Step 3.5: Under room temperature, homogenize and stir solution C, and add solution D dropwise into solution C to form a flocculent gel, thereby obtaining alkali-modified polylactic acid.

4. The method for preparing the natural cream according to claim 1, wherein: In step 2, the high temperature is 80-85° C.; in step 4, the homogenization condition is centrifugation at 6000-8000 rpm, and the homogenization time is 20-30 seconds.

5. The method for preparing the natural cream according to claim 1, wherein: The base is selected from sodium hydroxide or potassium hydroxide.

6. The method for preparing the natural cream according to claim 3, wherein: In step 3.3, the heating temperature is 85-95° C.; the dropwise addition rate is 0.01-0.1 g / min; and the stirring time is 2-5 hours.

7. The method for preparing the natural cream according to claim 3, wherein: In step 3.5, the homogenization conditions are centrifugation at 3000-5000 rpm, a homogenization time of 20-30 seconds, and formation of a flocculent gel when the solution temperature is close to room temperature.

8. The method for preparing the natural cream according to claim 1, wherein: In the preparation method, the alkali-modified polylactic acid is emulsified and dissolved in oil, avoiding the use of organic solvents to dissolve the polylactic acid.

9. The natural cream prepared by the preparation method according to any one of claims 1 to 8.

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