A water-soluble, breathable, skin protective film composition, and methods of making and using the same

Abstract

The application provides a water-soluble breathable skin protection film composition and a preparation method and application thereof, relates to the technical field of skin care products and functional coating, and the water-soluble breathable skin protection film composition contains the following components in percentage of total weight: (a) 5-30% of a film-forming polymer component, the film-forming polymer component is a combination of polyvinylpyrrolidone / vinyl acetate copolymer and partially alcoholized polyvinyl alcohol; (b) 5-25% of C2-C4 lower alcohol and / or C2-C10 aliphatic diol; (c) 0.01-10% of a polyether-modified silicone surfactant; (d) 0.01-18% of a functional auxiliary agent; (e) the balance is water. The composition can form a breathable film with a water vapor transmission rate greater than 500 g / (m 2 ·24h) on the skin, which can be removed within 90 seconds by using 25-30 DEG C normal temperature water. When used in medical treatment, the composition does not contain lower alcohol and has no irritation to damaged skin.

Description

Technical Field

[0001] This invention relates to the field of skin care products and functional coating technology, specifically to a water-soluble, breathable skin protective film composition, its preparation method, and its application. Background Technology

[0002] In daily life, people often need temporary protection for their hands and face to isolate them from oil, dust, makeup, or other impurities. Existing technological solutions have significant shortcomings: 1) Traditional latex / nitrile gloves: completely sealed, not breathable, uncomfortable to wear, and generate disposable plastic waste.

[0003] (ii) Oil-based protective products (such as petroleum jelly): They feel greasy on the skin, are not easy to wash off, and may absorb dirt themselves, so they cannot provide true physical protection.

[0004] (iii) Film-forming liquid adhesive tapes or "invisible gloves" have the following defects: 1) Most products (such as those based on polyvinyl alcohol (PVA) aim for strong adhesion and water resistance, resulting in films that are difficult to wash off quickly with room temperature water, requiring vigorous rubbing or the use of solvents. Some products add crosslinking agents (such as borax) to enhance performance, but this further makes them insoluble in water.

[0005] 2) Other products based on acrylic latex, although they can form a film, have poor breathability. Prolonged use may cause skin stuffiness, discomfort, or even folliculitis.

[0006] 3) Some patents emphasize water and abrasion resistance, and their film layers are strong, but they are difficult to clean and are not suitable for daily scenarios that require frequent and convenient removal.

[0007] (iv) Shortcomings of existing medical skin protection products: 1) Although spray film-forming products based on ethanol and other lower alcohols can form a film quickly, ethanol is irritating to broken skin and may cause stinging and burning sensations, making them unsuitable for use around wounds or postoperative skin.

[0008] 2) Some medical dressings, although breathable, cannot form a transparent film, which affects wound observation.

[0009] 3) Wound care dressings are mostly pre-formed patches, which are difficult to fit irregular areas (such as joints and face), and can easily cause secondary damage when changing them.

[0010] Therefore, the market urgently needs a composition that can simultaneously achieve "temporary protection", "skin breathability", "easy washing with cold water" and "high transparency without obscuring skin biological characteristics", especially in medical settings, where a non-irritating composition that can be used on broken skin while maintaining breathable film-forming properties is needed. Summary of the Invention

[0011] Based on in-depth research into the shortcomings of existing technologies, the inventors aim to develop a skin care composition that combines excellent protection, breathability, and easy cleanability. During the research and development process, the core technical challenge faced by the inventors lies in how to ensure that the film can be quickly washed away with cold water while simultaneously endowing it with sufficient mechanical strength, flexibility, and barrier properties against non-polar substances.

[0012] To achieve the above-mentioned objectives, the technical solution of this invention is as follows: The applicant initially used a single polyvinylpyrrolidone / vinyl acetate copolymer (PVP / VA). While the resulting film was readily soluble in cold water, it was brittle and easily broken, exhibiting extremely poor barrier properties against oily substances. In a chance experiment, by mixing a specific ratio of PVP / VA copolymer with partially alcoholyzed PVA in a specific solvent system, the inventor unexpectedly discovered that the resulting film, after drying, displayed an unprecedented combination of properties: it was neither as difficult to clean as a pure PVA film nor as fragile as a pure PVP / VA film. This invention is based on this unexpected discovery. By precisely controlling the types, ratios, and solvent systems of PVP / VA and PVA, this invention ultimately achieved a breakthrough in the long-considered "impossible triangle" of technology: high protection, high breathability, and rapid cold water washing. Specifically: A water-soluble, breathable skin protective film composition, comprising the following components by total weight percentage: (a) 5-30% of a film-forming polymer component, wherein the film-forming polymer component is a combination of polyvinylpyrrolidone / vinyl acetate copolymer and partially alcoholyzed polyvinyl alcohol; (b) 5-25% of C2-C4 lower alcohols and / or C2-C10 aliphatic diols; (c) 0.01-10% polyether-modified silicone surfactant; (d) 0.01-18% functional additives; said functional additives include volatile cyclic silicone oils; (e) The remainder is deionized water.

[0013] Furthermore, the polyvinylpyrrolidone / vinyl acetate copolymer accounts for 30-85% of the total weight of the film-forming polymer components, the partially hydrolyzed polyvinyl alcohol accounts for 15-70%, and the degree of hydrolysis of the partially hydrolyzed polyvinyl alcohol is 85%-92%.

[0014] Furthermore, in the polyvinylpyrrolidone / vinyl acetate copolymer, the molar ratio of vinylpyrrolidone to vinyl acetate is 10:(1-15).

[0015] Furthermore, the lower alcohol includes ethanol, propanol, or isopropanol; the C2-C10 aliphatic diol is at least one of 1,2-pentanediol, 1,2-hexanediol, octyl glycol, propylene glycol, and butanediol. Furthermore, the polyether-modified silicone surfactant includes PEG / PPG-modified polydimethylsiloxane.

[0016] Furthermore, the functional additive comprises at least one of the following: volatile cyclic silicone oil comprising 0.5-10% of the total weight of the composition; plasticizer comprising 0.1-5% of the total weight of the composition; skin-soothing or repairing active ingredient comprising 0.01-2% of the total weight of the composition; and rheology modifier comprising 0.05-1% of the total weight of the composition.

[0017] Furthermore, the volatile cyclic silicone oil includes cyclopentadimethylsiloxane (D5) or cyclohexylsiloxane (D6).

[0018] Furthermore, the plasticizer includes glycerin, propylene glycol, or sorbitol.

[0019] Furthermore, the active ingredients include ectoine, panthenol, dipotassium glycyrrhizate, or bisabolol.

[0020] Furthermore, the rheology modifier includes hydroxyethyl cellulose or xanthan gum.

[0021] A method for preparing a water-soluble, breathable skin protective film composition includes the following steps: S1: Mix the polyvinyl alcohol with a portion of water, heat to 85-95°C and stir until completely dissolved to obtain a polyvinyl alcohol solution, then cool. S2: Mix the remaining components, except for the polyether-modified silicone surfactant and the volatile cyclic silicone oil, with the remaining water and stir until dissolved or evenly dispersed to obtain a mixture. S3: Mix the polyvinyl alcohol solution obtained in step (1) with the mixture obtained in step (2) until homogeneous; S4: Add the polyether-modified silicone surfactant and volatile cyclic silicone oil (other than those mentioned in the above steps) to the S3 solution and mix thoroughly to obtain the final product; The water-soluble, breathable skin protective film composition was prepared using a method that, when applied to the skin surface in water at room temperature (25-30°C), forms a layer that can be washed away with water within 2 minutes, exhibiting a water vapor permeability greater than 500 g / (m²). 2 A breathable membrane (24h).

[0022] Application of a water-soluble, breathable skin protective film composition, said composition for forming a water-soluble, breathable film on the skin, said breathable film being washable with water within 90 seconds at room temperature (25-30°C), with a water vapor permeability greater than 500 g / (m²). 2 •24h).

[0023] Application of a water-soluble, breathable skin protective film composition in a temporary protective product that isolates the skin from oil, dust, and makeup.

[0024] The application of a water-soluble, breathable skin protective film composition in the skin after medical aesthetic procedures, around wounds, or in sensitive skin, wherein the protective film, when used as temporary protection, is non-irritating to broken skin.

[0025] The beneficial effects of this invention are: This invention provides a skin protective film composition that can quickly form a transparent, flexible, and breathable film on the skin, effectively isolating non-polar oils and microparticles. This film can be easily and quickly washed away with room temperature water without residue, providing an excellent user experience. This water-soluble, breathable skin protective film composition is non-irritating to broken skin when applied after cosmetic procedures, around wounds, or on sensitive skin.

[0026] By employing the formulation design of this invention, which simultaneously incorporates two film-forming polymers, the surface drying time is 25 seconds, significantly superior to other comparative formulations, resulting in a faster film-forming speed. This film not only possesses excellent flexibility and oil resistance but can also be completely and thoroughly washed away by room temperature water within 90 seconds, and in the fastest cases, can be cleaned in 60 seconds. Furthermore, its water vapor permeability reaches as high as 700 g / m³. 2 • 24h, far superior to similar products on the market, making this invention one of the few products that can simultaneously achieve fast film formation, easy washing, excellent breathability, and ensure skin comfort. This invention successfully resolves the contradictions between "quick drying and washability," "protection and breathability," and "durability and comfort" in existing formulations. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the embodiments of this invention will be described in detail below. It should be noted that the preparation methods described are merely exemplary and not intended to limit the invention. Those skilled in the art, after understanding the concept of this invention, can make appropriate adjustments, but all such adjustments should fall within the protection scope of this invention.

[0028] This invention provides a water-soluble, breathable skin protective film composition, made from the following raw materials in weight percentages: (a) 5-30% of a film-forming polymer component, wherein the film-forming polymer component is a combination of polyvinylpyrrolidone / vinyl acetate copolymer and partially alcoholyzed polyvinyl alcohol; (b) 5-25% of C2-C4 lower alcohols and / or C2-C10 aliphatic diols; (c) 0.01-10% polyether-modified silicone surfactant; (d) 0.01-18% functional additives; (e) The remainder is deionized water.

[0029] In embodiments of the present invention, the lower alcohol includes ethanol, propanol, or isopropanol; the C2-C10 aliphatic diol is at least one of 1,2-pentanediol, 1,3-hexanediol, octyl glycol, propylene glycol, and butanediol. The polyether-modified silicone surfactant includes PEG / PPG-modified polydimethylsiloxane.

[0030] The functional additive comprises at least one of the following: 0.5-10% by weight of a volatile cyclic silicone oil; 0.1-5% by weight of a plasticizer; 0.01-2% by weight of a skin-soothing or repairing active ingredient; and 0.05-1% by weight of a rheology modifier. The volatile cyclic silicone oil includes cyclopentasiloxane (D5) or cyclohexylsiloxane (D6). The plasticizer includes glycerin, propylene glycol, or sorbitol. The active ingredient includes ectoine, panthenol, dipotassium glycyrrhizate, or bisabolol. The rheology modifier includes hydroxyethyl cellulose or xanthan gum.

[0031] All raw materials used in this invention are commercially available ordinary-grade products. Specifically, the partially hydrolyzed polyvinyl alcohol (hydrolysis degree 85%-92%) used in this invention is obtained through the following channels: ① Japanese synthetic chemical company: Gohsenol EG series, hydrolysis degree 86.5-89.0%, models include EG-40, EG-30, EG-25, EG-05, etc., suitable for cosmetics and pharmaceutical fields. GL series / EG series hydrolysis degree is approximately 83-85%. Gohsenol GL series or EG series, hydrolysis degree is approximately 78-82%. ② Shaanxi Changji Fu Biotechnology: Pharmaceutical-grade PVA, hydrolysis degree 86-90%, models PVA05-88, PVA17-88, PVA24-88, meeting pharmaceutical excipient standards. ③ Sinopec Sichuan Vinylon Plant: PVA-1792 / PVA-1795 series, degree of alcoholysis 91.0 - 93.0%; PVA-1797 series, degree of alcoholysis 97.0% ④ Kuraray Corporation of Japan, PVA-124 series, degree of alcoholysis >99%, Poval series, degree of alcoholysis 96.0% - 97.0%.

[0032] In the formulation of the composite flavor attenuation inhibitor of this invention, the film-forming polymer component is used for film formation, water retention, and shaping; the C2-C4 lower alcohols and / or C2-C10 aliphatic diols are used to improve transparency and stability. The polyether-modified silicone surfactant is mainly used as a wetting, skin feel improver, and film-forming aid, which can improve system stability, spreadability, and skin adhesion, giving the product a silky and refreshing skin feel, and assisting in moisturizing and gentle penetration. Functional additives are mainly used to regulate system rheology, stabilize the formulation, enhance preservative efficacy, and improve skin feel, ensuring the safety, stability, and user comfort of cosmetics.

[0033] The embodiments of the present invention, by optimizing the addition amounts of film-forming polymer components, C2-C4 lower alcohols, C2-C10 aliphatic diols, polyether-modified organosilicon surfactants, functional additives, and deionized water, can fully exert synergistic effects and solve the problem of the inability to simultaneously achieve "quick drying and washability", "protection and breathability", and "durability and comfort".

[0034] The above-mentioned water-soluble and breathable skin protective film composition is prepared by the following method: S1: Preparation of aqueous phase A. Heat 30%-50% of the total amount of deionized water in the formula to 85°C-95°C, and slowly add polyvinyl alcohol while stirring. Maintain the temperature and continue stirring until the polyvinyl alcohol powder is completely dissolved, forming a transparent or slightly opalescent viscous solution. Stop heating and cool the solution to below 40°C for later use.

[0035] S2: Preparation of aqueous phase B. In another container, add the water-soluble or water-dispersible components of the formulation, that is, excluding the polyether-modified silicone surfactant and volatile cyclic silicone oil, including but not limited to: plasticizers, skin-soothing active ingredients, rheology modifiers, polyvinylpyrrolidone / vinyl acetate copolymers, C2-C4 lower alcohols and / or C2-C10 aliphatic diols, and the remaining deionized water for formulation. Stir at a moderate shear rate of 200-600 rpm using a mechanical stirrer at room temperature (15-30°C) until all solid or viscous components are completely dissolved or uniformly dispersed to form a homogeneous aqueous solution.

[0036] The process steps for preparing solutions of vinylpyrrolidone / vinyl acetate copolymer (PVP / VA copolymer) with different molar ratios are as follows: ① Monomer preparation: Calculate the amounts of N-vinylpyrrolidone (NVP) and vinyl acetate (VAc) according to the target molar ratio. NVP is divided into two parts: base NVP (accounting for 10%-30% of the total NVP) and drop-added NVP (accounting for 70%-90% of the total NVP); VAc is used entirely as base NVP.

[0037] ② Initiation system: Use a persulfate-sodium bisulfite redox initiation system or azobisisobutyramidine hydrochloride (AIBA). The amount of initiator is 0.2%-1.0% of the total monomer mass. Dissolve the initiator in NVP to prepare an initiator solution.

[0038] ③ Polymerization reaction: A. Add the base material NVP, all VAc and the calculated amount of deionized water to the reactor, start stirring (200-400 rpm), heat to 60-80℃, and keep warm for 10-15 min to stabilize the system.

[0039] B. Slowly add the initiator solution (including NVP) prepared in step ② to the reaction system using a dropping funnel. The dropping rate should be such that the reaction temperature is kept stable within ±2℃ of the set value.

[0040] C. After the addition is complete, continue the reaction at a constant temperature for 2-5 hours, and use high performance liquid chromatography (HPLC) to ensure that the monomer conversion rate is >98%.

[0041] Post-processing: After the reaction is complete, the obtained PVP / VA copolymer aqueous solution is cooled to room temperature, filtered through a 200-mesh filter to remove a small amount of insoluble matter, and after the solid content and viscosity are tested and found to be qualified, it can be used directly.

[0042] S3: Mixing and emulsifying.

[0043] While stirring, the cooled aqueous phase A solution obtained in step S1 is slowly added to the aqueous phase B obtained in step S2. After the addition is complete, the stirring speed is appropriately increased or a homogenizer is used for 30 seconds to 2 minutes to ensure that the system is mixed evenly and forms a stable mixture. The homogenizer includes a high-speed shear homogenizer with a rotation speed of 3000-8000 rpm. While stirring continuously, the volatile cyclic silicone oil and polyether-modified organosilicon surfactant in the formulation are added slowly in a thin stream or dropwise until the organic phase is completely dispersed to obtain a final composition with a uniform appearance.

[0044] S4: Post-processing. The resulting composition obtained in S3 is allowed to stand to eliminate air bubbles introduced by stirring. If necessary, it can be filtered before filling.

[0045] The following are specific embodiments and comparative examples of the present invention. It should be further noted that the schemes in the comparative examples are not prior art, but are only set up for comparison with the schemes in the embodiments, and are not intended to limit the present invention.

[0046] Example 1: A water-soluble breathable skin protective film composition, the raw material composition of which is: 12g of polyvinylpyrrolidone / vinyl acetate copolymer, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 6:4, 4g of fully alcoholyzed polyvinyl alcohol PVA-124 (degree of alcoholysis >99%, produced by Kuraray Co., Ltd., Japan), 18g of ethanol, 3g of PEG / PPG modified polydimethylsiloxane, 6g of PEG / PPG modified cyclopentamethoxysiloxane (D5), 1g of glycerin, and 56g of deionized water.

[0047] In Examples 1-7, the polyvinylpyrrolidone / vinyl acetate copolymer accounts for 50% of the total weight of the film-forming polymer component. The preparation methods used in Examples 1-7 all employ the general methods disclosed above.

[0048] Example 2: A water-soluble breathable skin protective film composition, the raw material composition of which is: 12g of polyvinylpyrrolidone / vinyl acetate copolymer, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 6:4, 4g of polyvinyl alcohol PVA-1797 (Sinopec Chuanwei PVA-1797 series, degree of alcoholysis is 97.0%), 18g of ethanol, 3g of PEG / PPG modified polydimethylsiloxane, 6g of PEG / PPG modified cyclopentamethoxysiloxane (D5), 1g of glycerin, and 56g of deionized water.

[0049] Example 3: A water-soluble breathable skin protective film composition, the raw material composition of which is: 12g of polyvinylpyrrolidone / vinyl acetate copolymer, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 6:4, 4g of polyvinyl alcohol PVA-1792 (degree of alcoholysis 92.0%, Sinopec Sichuan Vinylon Plant), 18g of ethanol, 3g of PEG / PPG modified polydimethylsiloxane, 6g of PEG / PPG modified cyclopentamethoxysiloxane (D5), 1g of glycerin, and 56g of deionized water.

[0050] Example 4: A water-soluble breathable skin protective film composition, the raw material composition of which is: 12g of polyvinylpyrrolidone / vinyl acetate copolymer, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 6:4, 4g of partially alcoholyzed polyvinyl alcohol PVA-1788 (degree of alcoholysis 88%), 18g of ethanol, 3g of PEG / PPG modified polydimethylsiloxane, 6g of PEG / PPG modified cyclopentamethoxysiloxane (D5), 1g of glycerin, and 56g of deionized water.

[0051] Example 5: A water-soluble, breathable skin protective film composition, the raw material composition of which is: 12g of polyvinylpyrrolidone / vinyl acetate copolymer, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 6:4, 4g of partially alcoholyzed polyvinyl alcohol (Japan Synthetic Chemicals GL series, degree of alcoholysis about 85%), 18g of ethanol, 3g of PEG / PPG modified polydimethylsiloxane, 6g of PEG / PPG modified cyclopentamethoxysiloxane (D5), 1g of glycerin, and 56g of deionized water.

[0052] Example 6: A water-soluble breathable skin protective film composition, the raw material composition of which is: 12g of polyvinylpyrrolidone / vinyl acetate copolymer, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 6:4, 4g of partially alcoholyzed polyvinyl alcohol (Japan Synthetic Chemicals EG series, degree of alcoholysis about 83%), 18g of ethanol, 3g of PEG / PPG modified polydimethylsiloxane, 6g of PEG / PPG modified cyclopentamethoxysiloxane (D5), 1g of glycerin, and 56g of deionized water.

[0053] Example 7: A water-soluble breathable skin protective film composition, the raw material composition of which is: 12g of polyvinylpyrrolidone / vinyl acetate copolymer, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 6:4, 4g of partially alcoholyzed polyvinyl alcohol (Japan Synthetic Chemicals EG series, degree of alcoholysis about 80%), 18g of ethanol, 3g of PEG / PPG modified polydimethylsiloxane, 6g of PEG / PPG modified cyclopentamethoxysiloxane (D5), 1g of glycerin, and 56g of deionized water.

[0054] Performance Tests and Results

[0055] Test method descriptions for Examples 1-7: Surface drying time: Under constant temperature and humidity (25°C, 50%RH) conditions, 0.1 mL of sample is spread on a 4 cm thick surface. 2 On a glass plate, the time it takes for the finger to no longer stick when lightly touched is recorded.

[0056] Cold water washability: Place the dried glass plate under flowing water at 25°C (flow rate 2L / min), and rub it in a circular motion with your fingertips under constant pressure (about 1N). Record the time it takes for the film to completely detach from the glass plate.

[0057] Water vapor transmission rate: According to GB / T 12704.1-2009 Textiles - Test methods for moisture permeability of fabrics - Part 1: Moisture absorption method.

[0058] Oil resistance test: Add 0.1 mL of soybean oil to a glass plate coated with a dry film, let it stand for 30 minutes, then use absorbent paper to remove the oil droplets on the surface and observe whether the back of the glass plate is transparent to oil.

[0059] Membrane toughness: Peel the membrane off the glass plate, bend it 180°, and observe whether it cracks.

[0060] Subjective skin feel rating: Ten trained reviewers will evaluate the "dryness, smoothness, and lack of residue" after using the product (out of 10).

[0061] Performance Tests and Results: The above embodiments were tested as follows, and the results are summarized in Table 1.

[0062] Table 1 Test Results of Examples 1-7

[0063] Results analysis:

[0064] From Examples 1-7, it can be seen that: 1. Surface drying time: Examples 1-6 can all be surface dried in about 30 seconds, demonstrating excellent fast-drying performance.

[0065] 2. Cold water washability: Examples 3-6 can all be completely washed within 90 seconds, demonstrating excellent performance. However, Example 1 (>300 seconds) is almost impossible to wash clean.

[0066] 3. Water vapor transmission rate: Examples 3-7 (650-700 g / m²) 2 It has excellent breathability (24h) and ensures skin comfort. Examples 1 and 2 have slightly poorer breathability.

[0067] 4. Resistance to edible oils: Examples 1-5 all showed "no penetration," indicating good protection. Example 6 showed slight penetration, and Example 7 showed partial penetration, indicating poor protection. Therefore, samples with good protection either cannot be washed with water, form a film very slowly, or have poor air permeability, while Examples 3-5 of this invention achieve a perfect balance between protection, washability, and air permeability.

[0068] 5. Membrane toughness: Examples 1-5 all showed "no cracks" and excellent toughness. Examples 6 and 7 were brittle and hard, and were easily damaged after film formation.

[0069] 6. Transparency and Skin Feel: The transparency of Examples 1-6 is "high", and the skin feel of Examples 3-5 is 7-9 points, which are the best in terms of visual effect and user experience.

[0070] Therefore, it can be seen that as the degree of PVA hydrolysis decreases (from >99% → 97% → 92% → 88% → 85% → 83% → 80%), cold water washability significantly improves, membrane toughness is greatly improved, water vapor permeability (breathability) gradually increases, and the skin feel score first increases and then decreases. The degree of PVA hydrolysis is a decisive parameter: it must be controlled between 85% and 92%. Below this range, the membrane is brittle and has poor oil resistance; above this range, it is difficult to clean. Example 4 (88%) is the optimal choice.

[0071] We selected Example 4 as the optimal example from Examples 1-7 above, and conducted further experiments based on Example 4 to obtain even better results: Example 8: Based on Example 4, other parameters remain unchanged, but 12g of polyvinylpyrrolidone / vinyl acetate copolymer is added, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 9:1.

[0072] Example 9: Based on Example 4, other parameters remain unchanged, but 12g of polyvinylpyrrolidone / vinyl acetate copolymer is added, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 8:2.

[0073] Example 10: Based on Example 4, other parameters remain unchanged, but 12g of polyvinylpyrrolidone / vinyl acetate copolymer is added, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 7:3.

[0074] Example 11: Based on Example 4, other parameters remain unchanged, but 12g of polyvinylpyrrolidone / vinyl acetate copolymer is added, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 5:5.

[0075] Example 12: Based on Example 4, other parameters remain unchanged, but 12g of polyvinylpyrrolidone / vinyl acetate copolymer is added, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 3:7.

[0076] Example 13: Based on Example 4, other parameters remain unchanged, but 12g of polyvinylpyrrolidone / vinyl acetate copolymer is added, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 1:9.

[0077] Using the test methods of Examples 1-7, the above Examples 8-13 were tested as follows, and the results are summarized in Table 2.

[0078] Table 2 Test Results of Examples 8-13

[0079] Based on Examples 8-13, we draw the following key conclusions: the performance of VP / VA copolymers does not follow a linear rule of "the more VP, the better" or "the more VA, the better." When VP > 80%, the film becomes sticky; when VA > 50%, cleaning becomes difficult and the film becomes brittle. Therefore, we unexpectedly found the optimal balance: a VP / VA molar ratio of 7:3 and 5:5 is the golden ratio for this system. Within this range, the crystalline network of PVA and the amorphous structure of VP / VA form the optimal interpenetrating network. This balances the seemingly contradictory requirements of "oil resistance and non-penetration" and "cold water washing within 90 seconds."

[0080] Through further structural analysis, the inventors revealed the mechanism of this synergistic effect: during film formation, numerous intermolecular hydrogen bonds are formed between the carbonyl groups on the PVP / VA molecular chains and the hydroxyl groups on the PVA molecular chains, constructing a robust yet reversible physical cross-linking network. This network provides excellent mechanical properties and density in a dry state to block external contaminants; however, when exposed to cold water, water molecules can rapidly penetrate and form stronger hydrogen bonds with these hydrophilic groups, thereby "disassembling" the original physical cross-linking network, causing the film to swell and disintegrate rapidly. Simultaneously, this network formed by the intertwining of two different molecular chains naturally generates a large number of nanoscale free volume vacancies, providing channels for water vapor diffusion, thus achieving excellent permeability.

[0081] Based on the above embodiments, we also conducted the following experiments: Example 15: A water-soluble, breathable skin protective film composition, comprising the following components based on a total weight of 100g: 10g of polyvinylpyrrolidone / vinyl acetate copolymer, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 7:3; 5g of polyvinyl alcohol PVA-1788 (degree of alcoholysis 88%); 18g of ethanol; 3g of PEG / PPG modified polydimethylsiloxane; 5g of cyclohexylsiloxane (D6); 1.0g of panthenol; 0.3g of ectoine; 0.2g of hydroxyethyl cellulose; and deionized water to a total weight of 100g (calculated value approximately 57.5g).

[0082] The polyvinylpyrrolidone / vinyl acetate copolymer is a product generated by copolymerizing N-vinylpyrrolidone (VP) and vinyl acetate (VA) in a certain proportion.

[0083] Preparation method: Prepared according to the general preparation method described above. Specifically, hydroxyethyl cellulose is pre-dispersed in a portion of deionized water to form an HEC solution. Polyvinylpyrrolidone / vinyl acetate copolymer, ethanol, polyether-modified silicone surfactant, panthenol, ectoine, the remaining water, and the HEC solution are mixed and stirred until completely dissolved. The pre-dissolved polyvinyl alcohol PVA-1788 solution from step S1 is added and stirred until homogeneous. Finally, cyclohexylsiloxane is slowly added while stirring and mixed until homogeneous to obtain the final product.

[0084] Example 16: A water-soluble, breathable skin protective film composition, comprising the following raw materials: 8g of polyvinylpyrrolidone / vinyl acetate copolymer, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 6:4; 6g of polyvinyl alcohol PVA-1788 (degree of alcoholysis 88%); 16g of ethanol; 2g of polyether-modified silicone oil; 4g of cyclopentamethoxysiloxane (D5); 2g of glycerin; and 62g of deionized water, for a total weight of 100g.

[0085] Preparation method: Prepared according to the general preparation method described above. Take about 25g of water to dissolve PVA-1788 in step S1, use the remaining components in step S2 according to the specified amount, and finally add D5 according to step S4 to obtain the final product.

[0086] Comparative Example 1: A water-soluble breathable skin protective film composition, the raw material composition of which is: 12g of polyvinylpyrrolidone (PVP) homopolymer, 4g of polyvinyl alcohol PVA-1788 (degree of alcoholysis 88%), 18g of ethanol, 3g of PEG / PPG modified polydimethylsiloxane, 6g of PEG / PPG modified cyclopentamethoxysiloxane (D5), 1g of glycerin, and 56g of deionized water.

[0087] Comparative Example 2: Silicone surfactants without polyether modification The polyether-modified silicone oil (3g) in Example 4 was replaced with an equal amount of deionized water, while other components and preparation methods remained unchanged.

[0088] Using the test methods of Examples 1-8, the above Examples 15, 16, Comparative Example 1, and Comparative Example 2 were tested as follows, and the results are summarized in Table 3.

[0089] Table 3 Test Results of Examples 15, 16, Comparative Example 1, and Comparative Example 2

[0090] in conclusion: This invention successfully constructs a water-soluble, breathable skin protective film that combines fast drying, toughness, oil resistance, breathability, easy washing, and a pleasant skin feel by synergistically compounding a polyvinylpyrrolidone / vinyl acetate copolymer with partially hydrolyzed polyvinyl alcohol and surface modification with a polyether-modified silicone surfactant. Compared with a single film-forming polymer (Comparative Example 1) and a silicone-free system (Comparative Example 2), the embodiments of this invention achieve an optimal balance in key indicators such as surface drying time, cold water washability, water vapor transmission rate, oil resistance, film toughness, transparency, and skin feel, resolving the contradictions between "fast drying and washability," "protection and breathability," and "durability and comfort" in the prior art.

[0091] When used in medical settings, lower alcohols can irritate damaged skin. Through further research and development, we have developed the following medical alcohol-free repair and protective film (for postoperative skin).

[0092] Example 14: A water-soluble, breathable skin protective film composition, comprising the following components based on a total weight of 100g: 10g of polyvinylpyrrolidone / vinyl acetate copolymer, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 6:4; 4g of polyvinyl alcohol PVA-1788 (88% degree of alcoholysis); 5g of 1,2-pentanediol; 2.5g of PEG / PPG modified polydimethylsiloxane; 4g of cyclohexylsiloxane (D6); 2g of panthenol; 0.5g of ectoine; and approximately 72g of deionized water. Preparation method: The preparation method described above is followed, wherein 1,2-pentanediol is added in step S2.

[0093] Performance Tests and Results: Table 4 Test Results of Example 14

[0094] Effects: This formula is free of lower alcohols and has been tested to be non-irritating to broken skin. Surface drying time is approximately 50-60 seconds, washability in cold water is approximately 80-90 seconds, and water vapor permeability is approximately 650 g / m². 2 • 24-hour use, suitable for post-medical aesthetic procedures and skin protection around wounds.

[0095] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A water-soluble, breathable skin protective film composition, characterized in that: It contains the following components by total weight percentage: (a) 5-30% of a film-forming polymer component, wherein the film-forming polymer component is a combination of polyvinylpyrrolidone / vinyl acetate copolymer and partially alcoholyzed polyvinyl alcohol; (b) 5-25% of C2-C4 lower alcohols and / or C2-C10 aliphatic diols; (c) 0.01-10% polyether-modified silicone surfactant; (d) 0.01-18% functional additives; (e) The remainder is deionized water; The degree of alcoholysis of the partially alcoholyzed polyvinyl alcohol is 85%-92%; in the polyvinylpyrrolidone / vinyl acetate copolymer, the molar ratio of vinylpyrrolidone to vinyl acetate is 10:(1-15). The lower alcohol is at least one of ethanol, propanol, or isopropanol; the C2-C10 aliphatic diol is at least one of 1,2-pentanediol, 1,2-hexanediol, octyl glycol, propylene glycol, and butanediol. The polyether-modified silicone surfactant includes PEG / PPG-modified polydimethylsiloxane; The functional additives include volatile cyclic silicone oils.

2. The water-soluble, breathable skin protective film composition according to claim 1, characterized in that: The polyvinylpyrrolidone / vinyl acetate copolymer accounts for 30-85% of the total weight of the film-forming polymer components, and the partially alcoholyzed polyvinyl alcohol accounts for 15-70%.

3. The water-soluble, breathable skin protective film composition according to any one of claims 1-2, characterized in that: The functional additive comprises at least one of the following: volatile cyclic silicone oil comprising 0.5-10% of the total weight of the composition; plasticizer comprising 0.1-5% of the total weight of the composition; skin-soothing or repairing active ingredient comprising 0.01-2% of the total weight of the composition; and rheology modifier comprising 0.05-1% of the total weight of the composition.

4. The water-soluble, breathable skin protective film composition according to claim 3, characterized in that: The volatile cyclic silicone oil includes cyclopentasiloxane (D5) or cyclohexylsiloxane (D6); the plasticizer includes glycerol, propylene glycol or sorbitol; The active ingredients include ectoine, panthenol, dipotassium glycyrrhizate, or bisabolol; The rheology modifier includes hydroxyethyl cellulose or xanthan gum.

5. A water-soluble, breathable skin protective film composition according to any one of claims 1-4, characterized in that: Its raw material composition is as follows: 12g of polyvinylpyrrolidone / vinyl acetate copolymer, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 6:4, 4g of polyvinyl alcohol PVA-1788, 18g of ethanol, 3g of PEG / PPG modified polydimethylsiloxane, 6g of PEG / PPG modified cyclopentamethoxysiloxane, 1g of glycerol, and 56g of deionized water; Alternatively: its raw materials, based on a total weight of 100g, include the following components: 10g of polyvinylpyrrolidone / vinyl acetate copolymer, wherein the molar ratio of polyvinylpyrrolidone to vinyl acetate is 6:4; 4g of polyvinyl alcohol PVA-1788; 5g of 1,2-pentanediol; 2.5g of PEG / PPG modified polydimethylsiloxane; 4g of cyclohexylsiloxane (D6); 2g of panthenol; 0.5g of ectoine; and 72g of deionized water. Among them, the degree of alcoholysis of polyvinyl alcohol PVA-1788 is 88%.

6. A method for preparing a water-soluble, breathable skin protective film composition according to any one of claims 1-5, characterized in that: Includes the following steps: S1: Mix the polyvinyl alcohol with a portion of water, heat to 85-95°C and stir until completely dissolved to obtain a polyvinyl alcohol solution, then cool. S2: Mix the remaining components, except for the polyether-modified silicone surfactant and the volatile cyclic silicone oil, with the remaining water and stir until dissolved or evenly dispersed to obtain a mixture. S3: Mix the polyvinyl alcohol solution obtained in step (1) with the mixture obtained in step (2) until homogeneous; S4: Add the polyether-modified silicone surfactant and volatile cyclic silicone oil (other than those in the above steps) to the S3 solution and mix thoroughly to obtain the final product.

7. The method for preparing a water-soluble, breathable skin protective film composition according to claim 6, characterized in that: In S2, at room temperature of 15-30°C, use a mechanical stirrer to stir at a moderate shear force of 200-600 rpm; In step S3, the cooled polyvinyl alcohol solution obtained in step S1 is slowly added to the mixture obtained in step S2. After the addition is completed, the stirring speed is increased or a homogenizing device is used to process the mixture for 30 seconds to 2 minutes. The homogenizing device includes a high-speed shear homogenizer with a rotation speed of 3000-8000 rpm. In S4, volatile cyclic silicone oil and polyether-modified silicone surfactant are added slowly in a thin stream or dropwise under continuous stirring until the organic phase is completely dispersed, resulting in a final composition with a uniform appearance. The resulting composition is then allowed to stand to eliminate air bubbles introduced by stirring, and then it can be filled.

8. The application of the water-soluble, breathable skin protective film composition as described in any one of claims 1-5, characterized in that: The composition is used to form a water-soluble, breathable film on the skin.

9. The application of the water-soluble, breathable skin protective film composition as described in claim 8, characterized in that: The breathable membrane can be washed away with water within 90 seconds, and its water vapor permeability is greater than 500 g / (m²). 2 •24h).

10. The use of the water-soluble, breathable skin protective film composition according to any one of claims 1-5 in a temporary protective product that isolates skin from oil, dust, and makeup, in post-medical aesthetic procedures, around wounds, or in sensitive skin.

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