CN114917148B - Sun protection preparation, preparation method thereof and cosmetics - Google Patents

Abstract

The present application belongs to the field of cosmetic technology, and particularly relates to a sunscreen preparation, a preparation method thereof, and cosmetics. The sunscreen preparation includes polylactic acid and a sunscreen filler dispersed in the polylactic acid; the sunscreen preparation not only has the radiation protection effect derived from the sunscreen filler, but also has the graded radiation effect brought by the spatial structure formed by the polylactic acid and the coated sunscreen filler; through radiation, the temperature transmitted from the outside is reduced to achieve the purpose of cooling; in addition, the polylactic acid has its own cooling effect brought by conduction, and also has the cooling effect brought by convection formed by the above-mentioned spatial structure, which enhances the cooling and sunscreen effect of the sunscreen preparation; applied to cosmetics, it has a strong cooling and skin-friendly feel.

Description

Sunscreen preparation and preparation method thereof and cosmetics

Technical Field

The present application belongs to the technical field of cosmetics, and in particular relates to a sunscreen preparation, a preparation method thereof, and cosmetics.

Background technique

Working outdoors for a long time is susceptible to ultraviolet radiation, which can easily cause skin damage, peeling, burning pain and erythema. For example, medium-wave ultraviolet rays can cause epidermal damage, and long-wave ultraviolet rays can cause dermal damage. At present, sunscreen products mainly rely on physical sunscreens or chemical sunscreens to reflect, scatter and absorb ultraviolet rays to reduce the impact of ultraviolet radiation.

When working outdoors, the skin temperature rises, which accelerates the evaporation of skin moisture, causing a series of skin problems, such as allergies, inflammation, active free radicals, etc. In the market, skin cooling products generally contain ethanol and menthol. These additives are easy to evaporate after absorbing heat, and the cooling effect is short-lived. They cannot solve the problem of skin fever for a long time. In addition, ethanol and menthol can easily penetrate the skin, which will cause potential skin problems.

Summary of the invention

The invention provides a sunscreen preparation and a preparation method thereof and cosmetics, which solve the technical problem that the cooling effect of the existing sunscreen preparations is short-lived.

In a first aspect, embodiments of the present application provide a sunscreen preparation comprising polylactic acid and a sunscreen filler dispersed in the polylactic acid.

According to an embodiment of the first aspect of the present application, the mass ratio of the sunscreen filler to the polylactic acid is (1-8):100.

According to an embodiment of the first aspect of the present application, the sunscreen filler is selected from boron nitride, titanium dioxide, zinc oxide or a combination thereof; and/or,

The particle size of the sunscreen filler is 0.01 to 0.5 μm.

According to an embodiment of the first aspect of the present application, the sunscreen filler is treated with a silane coupling agent.

According to an embodiment of the first aspect of the present application, the weight average molecular weight of the polylactic acid is 100,000 to 150,000.

In a second aspect, the present application provides a method for preparing a sunscreen preparation, the method comprising the following steps:

Providing a polylactic acid solution of polylactic acid in a first organic solvent;

The polylactic acid solution and the sunscreen filler are uniformly mixed in a second organic solvent to obtain a mixed solution,

The mixed solution is dried to obtain the sunscreen preparation.

According to another embodiment of the present application, the first organic solvent and the second organic solvent are respectively selected from chloroform, ethyl acetate, tetrahydrofuran or a combination thereof; and/or,

The mass ratio of the sunscreen filler to the polylactic acid is (1-8):100; and/or,

The weight average molecular weight of the polylactic acid is 100,000 to 150,000; and/or,

The mass ratio of the polylactic acid to the first organic solvent is 1 to 10:100, preferably 3 to 6:100.

According to an embodiment of the second aspect of the present application, the step of uniformly mixing the polylactic acid solution and the sunscreen filler in a second organic solvent to obtain a mixed solution comprises:

The polylactic acid solution and the sunscreen filler are ultrasonically treated in a second organic solvent to obtain a mixed solution.

According to an embodiment of the second aspect of the present application, based on the weight of the polylactic acid solution of 0.1 to 100 kg, the ultrasonic treatment time is 0.5-5 h, preferably 0.5-2 h.

In a third aspect, an embodiment of the present application provides a cosmetic, wherein the cosmetic comprises the sunscreen preparation described in the first aspect or the sunscreen preparation prepared by the method described in the second aspect;

The components of the cosmetics include a water phase composition, an oil phase composition and an emulsified composition. In the oil phase composition, the mass fraction of the sunscreen preparation is 1%-3%, preferably 2%.

The sunscreen preparation provided in the embodiment of the present application includes polylactic acid and a sunscreen filler dispersed in the polylactic acid, so that the sunscreen preparation not only has the radiation protection effect derived from the sunscreen filler, but also has the graded radiation effect brought about by the spatial structure formed by the polylactic acid and the coated sunscreen filler; through radiation, the temperature transmitted from the outside is reduced to achieve the purpose of cooling; in addition, the polylactic acid has a cooling effect brought about by conduction itself, and also has a cooling effect brought about by convection formed by the above-mentioned spatial structure, thereby enhancing the cooling and sunscreen effect of the sunscreen preparation; when applied to cosmetics, it has extremely strong cooling and skin-friendly feel.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solution of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

FIG1 is a schematic diagram of a process for preparing a sunscreen preparation according to an embodiment of the present application;

FIG2 is a schematic flow chart of a method for preparing a sunscreen formulation provided in yet another embodiment of the present application.

Detailed ways

In order to make the application purpose, technical solution and beneficial technical effect of the present application clearer, the present application is further described in detail in conjunction with the embodiments below. It should be understood that the embodiments described in this specification are only for explaining the present application, not for limiting the present application.

For simplicity, this application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unclearly recorded range; and any lower limit can be combined with other lower limits to form an unclearly recorded range, and any upper limit can be combined with any other upper limit to form an unclearly recorded range. In addition, although not clearly recorded, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined as its own lower limit or upper limit with any other point or single value or with other lower limits or upper limits to form an unclearly recorded range.

In the description of the present application, it should be noted that, unless otherwise specified, “above” and “below” are inclusive of the number, and the “multiple” in “one or more” means two or more than two.

The above application content of the present application is not intended to describe each disclosed embodiment or each implementation in the present application. The following description more specifically illustrates exemplary embodiments. In many places throughout the application, guidance is provided by a series of embodiments, which can be used in various combinations. In each example, enumeration is only used as a representative group and should not be interpreted as exhaustive.

A first aspect of the present application provides a sunscreen preparation comprising polylactic acid and a sunscreen filler dispersed in the polylactic acid.

At present, sunscreen products mainly rely on physical sunscreens or chemical sunscreens to reflect, scatter and absorb ultraviolet rays to achieve the purpose of sunscreen, but if the skin cooling effect is required, additional ingredients need to be added and the cooling effect is short-lived. The inventor has conducted a lot of research and found that a sunscreen with cooling effect can be provided, the main material of which is polylactic acid. Polylactic acid (polylactide, Poly lactic acid, English abbreviation PLA) is a synthetic biodegradable thermoplastic aliphatic polyester polymer material. The raw materials are derived from natural materials such as corn. It can be polymerized from lactide monomers extracted from plant sugars and belongs to a bio-based resin with 100% bio-based content. Polylactic acid itself has the characteristics of good biocompatibility, gloss, transparency, hand feel and heat resistance; at the same time, it also has good air permeability, oxygen permeability and carbon dioxide permeability, and also has the characteristics of isolating odors. In addition, polylactic acid is the only biodegradable plastic with excellent antibacterial and antifungal properties. It can give full play to its air permeability and antibacterial properties when used in cosmetics, and the plant-derived ingredient polylactic acid makes the product safe and environmentally friendly. However, PLA also has shortcomings, such as poor toughness. When used in cosmetics, it is easy to cause the cosmetic film layer applied to the skin to break and delaminate .

According to the embodiments of the present application, by adding a sunscreen filler to PLA, the heat resistance, radiation resistance and toughness of PLA can be improved, and the obtained material system can be used as a sunscreen preparation. The sunscreen preparation comprising a combination of PLA and a sunscreen filler can also achieve a cooling effect without adding additional ingredients, thereby improving the comfort and skin feel of the skin.

According to the embodiments of the present application, based on the spatial structure in which the sunscreen filler is dispersed in the polylactic acid to obtain the coating, as well as the fiber structure inside the polylactic acid crystal itself and the nanostructure inside the fiber, the spectrum from the solar radiation band to the mid-infrared band can be divided into three segments, and different levels of response can be performed to achieve precise control of the wide spectrum of ultraviolet, visible, near-infrared and mid-infrared bands, effectively avoiding crosstalk between spectra in different bands and improving the sunscreen effect.

According to an embodiment of one aspect of the present application, the intrinsic viscosity of the polylactic acid can be 0.2 to 8 dL/g, and optionally, 0.5 to 6 dL/g. When the polylactic acid has an intrinsic viscosity within the above range, the polylactic acid has a better viscosity and can provide a stable force to coat the sunscreen filler, forming a relatively uniform and stable structure, which can better wrap the sunscreen filler, so that the sunscreen preparation has stable performance in a variety of usage scenarios.

According to an embodiment of one aspect of the present application, the heat transfer coefficient of polylactic acid can be 0.025λ (w/m·k). When polylactic acid has the above heat transfer coefficient, it has excellent heat transfer performance, and can achieve a stable heat transfer effect when the sunscreen preparation is used on the skin, and achieve a certain degree of cooling effect.

In some embodiments, the mass ratio of the sunscreen filler to the polylactic acid is (1-8):100, and can be optionally (1.5-6):100.

According to the embodiment of the present application, when the mass ratio of the sunscreen filler to the polylactic acid is in the range of (1-8):100, the sunscreen filler is evenly distributed and has an excellent sunscreen effect. In addition, experiments have found that within this range, as the proportion of the sunscreen filler increases, the sunscreen effect is enhanced; but when the proportion is greater than 2%, the performance is not much different.

According to the embodiments of the present application, the mass ratio of the sunscreen filler to the polylactic acid is in the range of (1-8):100 and can be evenly dispersed in the polylactic acid. Beyond this ratio, the sunscreen filler may be partially uncoated or exist alone, affecting the effect of the sunscreen preparation. Within the above range, adding the sunscreen filler can enhance the sunscreen effect, but the sunscreen effect of the sunscreen preparation is poor.

In some embodiments, the sunscreen filler is selected from boron nitride, titanium dioxide, zinc oxide, or a combination thereof.

According to the embodiments of the present application, the sunscreen fillers include but are not limited to: boron nitride, titanium dioxide, zinc oxide, all of which have sunscreen effects, and any one or several sunscreen fillers can be selected for dispersion in polylactic acid.

In some embodiments, the particle size of the sunscreen filler is 0.01 to 0.5 μm, optionally 0.01 to 0.03 μm.

According to the embodiments of the present application, the particle size of the sunscreen filler can be between 0.01 and 0.5 μm, and the applicable range is relatively wide. It can be any one or several of the sunscreen fillers of 0.01 to 0.5 μm, 0.01 to 0.03 μm, 0.05 to 0.08 μm, 0.1 to 0.18 μm, 0.19 to 0.21 μm, 0.24 to 0.35 μm, 0.36 to 0.43 μm, and 0.45 to 0.5 μm. By utilizing sunscreen fillers with different particle sizes and different sunscreen mechanisms, a comprehensive sunscreen effect can be achieved.

According to the embodiments of the present application, the sunscreen filler can only add one particle size sunscreen filler, or can add multiple particle sizes of sunscreen fillers at the same time, and the ratio is not limited. The smaller the particle size of the sunscreen filler, the better the dispersibility in the polylactic acid, the more stable the polylactic acid coating, the more homogeneous and stable the sunscreen effect achieved, and the finer the sunscreen preparation when used. The particle size of the sunscreen filler will also affect the sunscreen mechanism. Its anti-ultraviolet ability and its mechanism are related to its particle size. For example, when the particle size in the sunscreen filler is large, the blocking of ultraviolet rays is mainly based on reflection and scattering, and it is effective for both medium-wave and long-wave ultraviolet rays. The sunscreen mechanism is a simple covering, which belongs to general physical sunscreen and has a weak sunscreen ability; as the particle size decreases, light can pass through the particle surface such as titanium dioxide, and the reflection and scattering of long-wave ultraviolet rays are not obvious, while the absorption of medium-wave ultraviolet rays is significantly enhanced. Its sunscreen mechanism is to absorb ultraviolet rays, mainly absorbing medium-wave ultraviolet rays.

In some embodiments, the sunscreen filler is treated with a silane coupling agent.

According to the embodiments of the present application, the sunscreen filler is treated with a silane coupling agent, and the silane coupling agent can be used to improve the dispersibility of the filler, reduce its expansion, enhance the water vapor permeability, or enhance the adhesion and compatibility with polylactic acid, or the silane coupling agent is located between the sunscreen filler and the polylactic acid to enhance the reinforcement properties of the sunscreen preparation.

In other embodiments, the sunscreen filler is not treated with a silane coupling agent.

According to the embodiments of the present application, the sunscreen filler may not be treated with a silane coupling agent and may directly contact with polylactic acid, thereby reducing the production process and saving costs. In addition, the sunscreen filler that has not been treated with a silane coupling agent can be evenly dispersed with polylactic acid, and the two may work synergistically with each other to achieve a stable cooling and sunscreen effect.

In some embodiments, the weight average molecular weight of the polylactic acid is 100,000 to 150,000.

According to an embodiment of the present application, the weight average molecular weight of polylactic acid may be 100,000 to 150,000, and optionally, 110000 to 120000. When polylactic acid has a molecular weight within the above range, polylactic acid and sunscreen fillers form a relatively uniform and stable dispersed structure, and polylactic acid can better wrap the sunscreen filler, so that the sunscreen preparation has stable performance in a variety of usage scenarios.

In a second aspect, the present invention provides a method for preparing a sunscreen preparation, as shown in FIG1 , the method comprising the following steps:

S1. Providing a polylactic acid solution of polylactic acid in a first organic solvent;

S2. The polylactic acid solution and the sunscreen filler are uniformly mixed in a second organic solvent to obtain a mixed solution;

S3. Drying the mixed solution to obtain the sunscreen preparation.

According to the embodiments of the present application, polylactic acid is an organic material insoluble in water, which can be dissolved in a first organic solvent and evenly mixed with a sunscreen filler; the second organic solvent can be an emulsion-type solvent, which has better dispersibility for powders and better ductility on the surface.

In the embodiment of the present application, the polylactic acid solution of step S1 can be purchased from a commercial product; or it can be prepared by the inventor. During the preparation, the polylactic acid is mixed and stirred with the first organic solvent, and the stirring time can be 1-10 hours, and can be optionally 1.5-4 hours.

In the embodiment of the present application, drying may include vacuum drying or reduced pressure drying, which is a drying method in which the material is placed under low pressure or negative pressure conditions and appropriately heated to reach the boiling point under low pressure or negative pressure conditions or cooled to solidify the material and then dry the material through the melting point. Other drying methods may also be used.

In some embodiments, the first organic solvent and the second organic solvent are respectively selected from chloroform, ethyl acetate, tetrahydrofuran or a combination thereof.

In some embodiments, the mass ratio of the polylactic acid to the first organic solvent is 1 to 10:100, and can be optionally 3 to 6:100.

In the embodiment of the present application, the mass ratio of the polylactic acid to the first organic solvent is controlled to be 1 to 10:100, which can ensure that the polylactic acid is dissolved in a sufficient amount of the first organic solvent.

According to an embodiment of the second aspect of the present application, a method for preparing a sunscreen preparation is provided, as shown in FIG2 , the method comprising the following steps, specifically comprising:

S100. Providing a polylactic acid solution of polylactic acid in a first organic solvent;

S200. The polylactic acid solution and the sunscreen filler are ultrasonically treated in a second organic solvent to obtain a mixed solution;

S300. Drying the mixed liquid to obtain the sunscreen preparation.

Ultrasonic treatment uses the energy, power characteristics and cavitation of ultrasound to change or accelerate the change of certain physical, chemical, biological properties or states of matter.

According to the embodiments of the present application, ultrasonic treatment may generate hydrogen bonding, intermolecular forces, adsorption forces and other forces between polylactic acid and the sunscreen filler, and polylactic acid is coated on the surface of the sunscreen filler through the corresponding forces; the dispersion speed of the polylactic acid solution and the sunscreen filler is accelerated, and the purpose of polylactic acid coating the sunscreen filler is achieved, so that the polylactic acid and the sunscreen filler can cooperate with each other to play their role.

In some embodiments, after step S200, a crude product may be obtained, which may be washed with a second organic solvent to remove excess sunscreen filler.

In some embodiments, the first organic solvent and the second organic solvent can be removed by drying to obtain a crude product of polylactic acid-encapsulated sunscreen filler.

In some embodiments, the sunscreen preparation added to cosmetics generally has certain particle size requirements and needs to be crushed to obtain a sunscreen preparation that meets the particle size requirements.

In the embodiments of the present application, a pulverizer can be used for pulverization, and the pulverization rate of the pulverizer can be 1000-4000 rpm, and can be optionally 2000-3000 rpm. Any pulverization rate that can achieve the particle size requirement of the sunscreen preparation is acceptable.

In some embodiments, based on the weight of the polylactic acid solution of 0.1 to 100 kg, the ultrasonic treatment time is 0.5-5 h, and can be optionally 0.5-2 h.

In the embodiment of the present application, the weight of the polylactic acid solution is 0.1 to 100 kg, and only 0.5 to 5 hours is needed to meet the requirements of ultrasonic treatment. If the time is too long, the production efficiency is low. If the time is less than 0.5 hours, the effect of ultrasonic treatment cannot be achieved, and the effect of polylactic acid coating the sunscreen filler is not good, which may cause the quality of the polylactic acid coating the sunscreen filler to be relatively low, or the coating is incomplete, or the coating part is not uniform, affecting the cooling and sunscreen effects.

In a third aspect, an embodiment of the present application provides a cosmetic, wherein the cosmetic comprises the sunscreen preparation described in the first aspect or the sunscreen preparation prepared by the method described in the second aspect;

The components of the cosmetics include a water phase composition, an oil phase composition and an emulsified composition. In the oil phase composition, the mass fraction of the sunscreen preparation is 1%-3%, and can be 2%.

According to the embodiments of the present application, 1%-3% of the sunscreen preparation is added to the oil phase composition without increasing the compatibility burden of the oil phase composition, and is compatible with the oil phase composition and dispersed evenly.

According to the embodiments of the present application, the obtained sunscreen preparation with cooling effect is used on human skin, with a strong cooling effect, making the skin surface temperature 2-10°C lower than the ambient temperature, thereby reducing skin heat, making the skin comfortable, and having a strong experience and skin feel.

Example

The following examples more specifically describe the disclosure of the present application, which are intended for illustrative purposes only, as it will be apparent to those skilled in the art that various modifications and variations may be made within the scope of the disclosure of the present application. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further processing, and the instruments used in the examples are commercially available.

Embodiment 1

The preparation method of the cooling sunscreen preparation of the embodiment of the present application is specifically implemented as follows: in a 500mL reactor, add 8g of polylactic acid particles (PLA, average molecular weight of about 11×10 ⁴ , homemade) and 200mL of CHCl ₃ (chloroform), and stir for 2h to fully dissolve the polylactic acid particles; add 2% of the weight of polylactic acid boron nitride solid powder into 50mL of chloroform emulsion and ultrasonicate for 1h, wash with chloroform for 2-3 times after the reaction, and after the solvent evaporates, collect the product and crush it to obtain modified PLA particles for later use.

Embodiment 2

The preparation method of the cooling sunscreen preparation of the embodiment of the present application is specifically implemented as follows: in a 500mL reactor, add 8g of polylactic acid particles (PLA, average molecular weight of about 11×10 ⁴ , homemade) and 200mL of CHCl ₃ (chloroform), and stir for 2h to fully dissolve the polylactic acid particles; add 2% of the weight of polylactic acid titanium dioxide solid powder into 50mL chloroform emulsion and ultrasonicate for 1h, wash with chloroform for 2-3 times after the reaction, and after the solvent evaporates, collect the product and crush it to obtain modified PLA particles for later use.

Embodiment 3

The preparation method of the cooling sunscreen preparation of the embodiment of the present application is specifically implemented as follows: in a 500mL reactor, add 8g of polylactic acid particles (PLA, average molecular weight of about 11×10 ⁴ , homemade) and 200mL of CHCl ₃ (chloroform), and stir for 2h to fully dissolve the polylactic acid particles; add 2% of the weight of polylactic acid solid zinc oxide powder into 50mL chloroform emulsion and ultrasonicate for 1h, wash with chloroform for 2-3 times after the reaction, and after the solvent evaporates, collect the product and crush it to obtain modified PLA particles for later use.

Embodiment 4

The preparation method of the cooling sunscreen preparation of the embodiment of the present application is specifically implemented as follows: in a 500mL reactor, add 8g of polylactic acid particles (PLA, average molecular weight of about 11×10 ⁴ , homemade) and 200mL of CHCl ₃ (chloroform), and stir for 2h to fully dissolve the polylactic acid particles; add 0.5% of the weight of polylactic acid titanium dioxide solid powder into 50mL chloroform emulsion and ultrasonicate for 1h, wash with chloroform 2-3 times after the reaction, and after the solvent evaporates, collect the product and crush it to obtain modified PLA particles for later use.

Embodiment 5

The preparation method of the cooling sunscreen preparation of the embodiment of the present application is specifically implemented as follows: in a 500mL reactor, add 8g of polylactic acid particles (PLA, average molecular weight of about 11×10 ⁴ , homemade) and 200mL of CHCl ₃ (chloroform), and stir for 2h to fully dissolve the polylactic acid particles; add 4% of the weight of polylactic acid titanium dioxide solid powder into 50mL chloroform emulsion and ultrasonicate for 1h, wash with chloroform for 2-3 times after the reaction, and after the solvent evaporates, collect the product and crush it to obtain modified PLA particles for later use.

Embodiment 6

The preparation method of the cooling sunscreen preparation of the embodiment of the present application is specifically implemented as follows: in a 500mL reactor, add 8g of polylactic acid particles (PLA, average molecular weight of about 11×10 ⁴ , homemade) and 200mL of CHCl ₃ (chloroform), and stir for 2h to fully dissolve the polylactic acid particles; add 6% of the weight of polylactic acid titanium dioxide solid powder, add 50mL of chloroform emulsion and ultrasonicate for 1h, wash with chloroform for 2-3 times after the reaction, and after the solvent evaporates, collect the product and crush it to obtain modified PLA particles for later use.

Comparative Example

PLA pellets not treated with sunscreen fillers.

Sunscreen cooling test

Sunscreen (experimental group): calculated by mass percentage (the sum of all components is 100%), phase A components: deionized water: 46.4%, glycerol: 5%, 1,2-pentanediol: 1%, potassium cetyl phosphate: 0.8%, ammonium acryloyldimethyltaurate/VP copolymer: 0.2%, VP/acrylic acid (esters)/lauryl methacrylate copolymer: 1.5%;

Phase B components: by mass percentage, any sample of Examples 1-6: 2%, glyceryl stearate/PEG-100 stearate: 1.5%, cetearyl alcohol: 8%, butyl methoxydibenzoylmethane: 4%, bis-ethylhexyloxyphenol methoxyphenyl triazine: 8%, octocrylene: 8%, ethylhexyl salicylate: 4%, ethylhexyl triazone: 4%;

Phase C components: Silica: 2%, C30-45 Alkyl Cetearyl Dimethicone Crosspolymer: 3%, Preservative: 0.5%, Fragrance: 0.1%.

The preparation method steps of the above embodiment are as follows:

1) Add the components of phase A into the water phase pot, heat to 80°C, and stir until completely dissolved;

2) Add the components of phase B into the oil phase pot, heat to 80°C, and stir until completely dissolved;

3) Pump each component of phase A into the emulsification pot, and pump each component of phase B into the emulsification pot. After the two are fully stirred, start homogenization and emulsification, and keep warm;

4) Stir the product of 3) and cool it to 45°C, add the components of phase C into the emulsifying pot, stir evenly, and homogenize if necessary. After passing the inspection, filter the material to prepare the sunscreens of experimental groups 1-6 respectively.

Sunscreen control group 1: except that component B did not contain the sample of the embodiment, and component A contained deionized water +2% (changed to 48.4%), the rest remained unchanged.

Sunscreen control group 2: The B component is replaced with the polylactic acid prepared in the comparative example to obtain a sample.

30 subjects who met the requirements were selected to evenly apply the sunscreen on their faces. They were then exposed to sunlight for 2h and 4h, and the difference in skin temperature before and after applying the sunscreen was tested.

Table 1 Cooling effect of various sunscreens.

The results show that compared with the comparative example, the modified PLA added in the embodiment does have a cooling effect on the sunscreen compared with the unmodified PLA. Compared with the metal oxides, titanium dioxide and zinc oxide have better performance than boron nitride, which may be because titanium dioxide and zinc oxide are physical sunscreens. In addition, as the proportion of metal oxides increases, when the proportion is greater than 2%, the performance is not much different. In addition, compared with the comparative example, the embodiment has a longer cooling effect. In addition, when the proportion of titanium dioxide is too large, the sunscreen will turn white, which is due to the high concealing effect of titanium dioxide.

Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims (11)

1. A sunscreen formulation comprising polylactic acid and a sunscreen filler dispersed in the polylactic acid;

The mass ratio of the sun-proof filler to the polylactic acid is (1-8) 100; the weight average molecular weight of the polylactic acid is 100,000 ～ 150,000.

2. The sunscreen formulation according to claim 1, wherein the sunscreen filler is selected from the group consisting of boron nitride, titanium dioxide, zinc oxide, or a combination thereof; and/or the number of the groups of groups,

The particle size of the sun-screening filler is 0.01-0.5 mu m.

3. The sunscreen formulation of claim 1 wherein the sunscreen filler is treated with a silane coupling agent.

4. A process for the preparation of a sunscreen according to claim 1, comprising the steps of:

Providing a polylactic acid solution of polylactic acid in a first organic solvent;

Uniformly mixing the polylactic acid solution and the sun-proof filler in a second organic solvent to obtain a mixed solution,

Drying the mixed solution to obtain the sun-proof preparation.

5. The method of claim 4, wherein the first and second organic solvents are each selected from the group consisting of chloroform, ethyl acetate, tetrahydrofuran, and combinations thereof; and/or the number of the groups of groups,

The mass ratio of the polylactic acid to the first organic solvent is (1-10): 100.

6. The method according to claim 4, wherein the mass ratio of the polylactic acid to the first organic solvent is (3 to 6): 100.

7. The method according to claim 4, wherein uniformly mixing the polylactic acid solution and the sun-protecting filler in the second organic solvent to obtain the mixed solution comprises:

and carrying out ultrasonic treatment on the polylactic acid solution and the sun-screening filler in a second organic solvent to obtain a mixed solution.

8. The method of claim 7, wherein the step of determining the position of the probe is performed,

The ultrasonic treatment time is 0.5-5h based on the weight of the polylactic acid solution of 0.1-100 kg.

9. The method according to claim 7, wherein the ultrasonic treatment is performed for 0.5 to 2 hours based on the weight of the polylactic acid solution of 0.1 to 100 kg.

10. A cosmetic product, characterized in that it comprises a sunscreen preparation according to any one of claims 1 to 3 or a sunscreen preparation obtainable by a process according to any one of claims 4 to 9;

the components of the cosmetic comprise an aqueous phase composition, an oil phase composition and an emulsifying composition, and the mass fraction of the sun-proof preparation is 1% -3% of that of the cosmetic.

11. The cosmetic according to claim 10, wherein the mass fraction of the sunscreen preparation is 2% of the cosmetic.