Zinc oxide foam and preparation method thereof

Abstract

The present invention relates to the technical field of zinc oxide foam, and a kind of zinc oxide foam and preparation method thereof is provided.The zinc oxide foam comprises the following raw materials: isobutane, zinc oxide, 1,2-butylene glycol, polydimethylsiloxane, caprylic acid / capric acid triglyceride, steareth-21, cetearyl alcohol, glycerol, D-panthenol, sunflower seed oil, propane, steareth-2, hydroxypropyl methylcellulose, parahydroxyacetophenone, 1,2-hexanediol, 1,3-propylene glycol, marigold extract, phenoxyethanol, methylparaben and water.The zinc oxide foam of the present invention has lower foam density and higher foam stability, has good ultraviolet protection effect, and can absorb skin grease, regulate skin microenvironment, and contribute to wound healing.At the same time, due to the characteristics of its foam formulation, it can be easy to use, evenly distributed, will not leave obvious white residue on the skin, and provides a pleasant sensory experience.

Description

Technical Field

[0001] The invention relates to the technical field of zinc oxide foam, and specifically provides a zinc oxide foam and a preparation method thereof. Background Art

[0002] Zinc oxide is widely used in many personal care products, including sunscreens, prickly heat powders, baby sprays, and facial masks. Its primary functions include providing UV protection, absorbing oil and moisture, regulating the skin's microenvironment, and aiding in wound healing. Furthermore, zinc oxide has been found to have a positive effect on combating skin infections, inhibiting the growth of skin pathogens such as Staphylococcus aureus and Candida albicans.

[0003] While zinc oxide's numerous benefits in skin care and protection are widely recognized by users and professionals, its practical application still presents some significant limitations. Traditional zinc oxide products, often in the form of creams and lotions, while effective in treating and protecting the skin, present several issues that impact the user experience, particularly in terms of appearance and convenience.

[0004] First, these traditional zinc oxide formulations often leave a noticeable white residue on the skin. This phenomenon is primarily due to the physical properties of zinc oxide itself: when applied to the skin, zinc oxide particles form a visible white coating. This problem can cause significant inconvenience to users during social interactions and daily activities, especially when using zinc oxide products on the face or other conspicuous areas. The presence of this white residue can affect users' self-confidence, disrupting their daily lives and social activities. Therefore, despite the excellent skincare benefits of zinc oxide, this undesirable appearance has, to some extent, hindered the widespread use and acceptance of zinc oxide products.

[0005] Secondly, traditional zinc oxide formulations typically require direct application with fingers or cotton swabs, which can result in uneven distribution of the product across the skin. This uneven distribution can not only compromise product effectiveness but also lead to over-application in some areas and under-application in others, preventing the full protective effect of zinc oxide. Furthermore, hand cleanliness can impact product effectiveness. Contaminated hands can introduce contaminants into the product, compromising its cleanliness and stability.

[0006] Therefore, it is crucial to develop a new zinc oxide product to address the above issues. The ideal new product should be easy to use, spread evenly on the skin, leave no noticeable white residue, and fully utilize the multiple benefits of zinc oxide.

[0007] In recent years, foam-based formulations have become increasingly popular in a variety of personal care products, including cleansers, skincare, and haircare. Foam-based formulations offer many advantages, such as ease of use, uniform distribution, and a pleasant sensory experience. However, to date, there have been no reports on the development of zinc oxide products using this formulation.

[0008] Therefore, there is an urgent need to develop a new zinc oxide foam product that can fully utilize the various advantages of zinc oxide while avoiding the disadvantages of traditional zinc oxide products. In addition, the new product should be easy to use, spread evenly on the skin, leave no white residue, and provide a pleasant sensory experience. Summary of the Invention

[0009] In view of the defects of the prior art, the present invention provides a zinc oxide foam and a preparation method thereof.

[0010] The present invention provides a zinc oxide foam comprising zinc oxide and a propellant, wherein the propellant is isobutane and / or propane. This zinc oxide foam product can protect the skin from UV damage while also producing a foam form that is easy to use due to the specific propellant.

[0011] Preferably, the zinc oxide foam further comprises a moisturizer, which is at least one of 1,2-butylene glycol, glycerol, D-panthenol, betaine, sodium hyaluronate, urea, trehalose, tremella polysaccharide, dextran, 1,2-hexanediol and 1,3-propylene glycol.

[0012] Preferably, the zinc oxide foam further comprises a preservative, and the preservative is at least one of phenoxyethanol, p-hydroxyacetophenone, ethylhexylglycerin, sodium benzoate, caprylyl glycol and methylparaben.

[0013] Preferably, the zinc oxide foam further comprises an emulsifier, and the emulsifier is at least one of steareth-21, steareth-2, sodium stearoyl glutamate, potassium cetyl phosphate, glyceryl stearate, sucrose stearate, cetearyl glucoside, ceteareth-20, PEG-100 stearate, fatty acid and Tween 60.

[0014] Preferably, the zinc oxide foam further comprises a thickener, and the thickener is at least one of carbomer, xanthan gum, Sphingomonas fermentation extract, microcrystalline cellulose, cellulose gum, cyclodextrin, polyacrylate crosspolymer-6, ammonium acryloyldimethyltaurate / VP copolymer and hydroxypropyl methylcellulose.

[0015] Preferably, the zinc oxide foam further comprises oil, and the oil is at least one of sunflower seed oil, olive oil, almond oil, jojoba oil, coconut oil, shea butter, squalane, isohexadecane, caprylic / capric triglyceride, silicone oil, isononyl isononanoate and dicaprylyl carbonate.

[0016] Preferably, the zinc oxide foam comprises the following raw materials: isobutane, zinc oxide, 1,2-butylene glycol, dimethicone, caprylic / capric triglyceride, steareth-21, cetearyl alcohol, glycerin, D-panthenol, sunflower seed oil, propane, steareth-2, hydroxypropyl methylcellulose, parahydroxyacetophenone, 1,2-hexanediol, 1,3-propylene glycol, calendula officinalis extract, phenoxyethanol, methylparaben and water.

[0017] The invention provides a zinc oxide foam, which comprises the following raw materials: isobutane, zinc oxide, 1,2-butylene glycol, dimethicone, caprylic / capric triglyceride, steareth-21, cetearyl alcohol, glycerin, D-panthenol, sunflower seed oil, propane, steareth-2, hydroxypropyl methylcellulose, p-hydroxyacetophenone, 1,2-hexanediol, 1,3-propylene glycol, calendula officinalis flower extract, phenoxyethanol, methylparaben and water.

[0018] Preferably, a zinc oxide foam comprises the following raw materials in percentage by weight:

[0019] Isobutane: 5-10%;

[0020] Zinc oxide: 3-10%;

[0021] 1,2-Butanediol: 3-10%;

[0022] Polydimethylsiloxane: 3-10%;

[0023] Caprylic / capric triglyceride: 2-10%;

[0024] Stearyl alcohol polyether-21: 2-10%;

[0025] Cetearyl alcohol: 1-5%;

[0026] Glycerol: 1-5%;

[0027] D-panthenol: 1-5%;

[0028] Sunflower seed oil: 1-5%;

[0029] Propane: 1-5%;

[0030] Stearyl alcohol polyether-2: 1-5%;

[0031] Hydroxypropyl methylcellulose: 0.5-3%;

[0032] p-Hydroxyacetophenone: 0.02-0.16%;

[0033] 1,2-Hexanediol: 0.1-0.5%;

[0034] 1,3-Propanediol: 0.1-0.5%;

[0035] Calendula extract: 0.05-0.5%;

[0036] Phenoxyethanol: 0.01-0.12%;

[0037] Methylparaben: 0.01-0.12%;

[0038] The balance is water.

[0039] Preferably, a zinc oxide foam comprises the following raw materials in percentage by weight:

[0040] Isobutane: 6-8%;

[0041] Zinc oxide: 4-6%;

[0042] 1,2-Butanediol: 4-6%;

[0043] Polydimethylsiloxane: 4-6%;

[0044] Caprylic / capric triglyceride: 3-5%;

[0045] Stearyl alcohol polyether-21: 3-5%;

[0046] Cetearyl alcohol: 2-4%;

[0047] Glycerol: 2-4%;

[0048] D-panthenol: 1-3%;

[0049] Sunflower seed oil: 1-3%;

[0050] Propane: 1-3%;

[0051] Stearyl alcohol polyether-2: 1-3%;

[0052] Hydroxypropyl methylcellulose: 0.7-2%;

[0053] p-Hydroxyacetophenone: 0.03-0.08%;

[0054] 1,2-Hexanediol: 0.1-0.3%;

[0055] 1,3-Propanediol: 0.1-0.3%;

[0056] Calendula extract: 0.05-0.2%;

[0057] Phenoxyethanol: 0.02-0.06%;

[0058] Methylparaben: 0.02-0.06%;

[0059] The balance is water.

[0060] The present invention also provides a method for preparing the zinc oxide foam, comprising the following steps:

[0061] Dissolving hydroxypropyl methylcellulose in water to form a hydroxypropyl methylcellulose solution;

[0062] Mix zinc oxide, 1,2-butylene glycol, dimethicone, caprylic / capric triglyceride, steareth-21, cetearyl alcohol, glycerin, D-panthenol, helianthus annuus seed oil, and steareth-2 to form a preliminary mixture;

[0063] Add 1,2-hexanediol, 1,3-propylene glycol, calendula officinalis extract, p-hydroxyacetophenone, phenoxyethanol, and methylparaben to the preliminary mixed solution, stir to obtain a mixture; then add to the hydroxypropyl methylcellulose solution;

[0064] Homogenization;

[0065] Fillable with isobutane and propane.

[0066] Preferably, a method for preparing zinc oxide foam comprises the following steps:

[0067] Dissolve hydroxypropyl methylcellulose in water at room temperature and stir for 2-6 hours to form a hydroxypropyl methylcellulose solution;

[0068] Mix zinc oxide, 1,2-butylene glycol, dimethicone, caprylic / capric triglyceride, steareth-21, cetearyl alcohol, glycerin, D-panthenol, sunflower seed oil, and steareth-2, and stir at 50-70°C for 15-25 minutes until uniform to form a preliminary mixed solution;

[0069] Add 1,2-hexanediol, 1,3-propylene glycol, calendula officinalis extract, p-hydroxyacetophenone, phenoxyethanol, and methylparaben to the preliminary mixed solution, and continue stirring at 50-70° C. for 15-25 minutes to obtain a mixture;

[0070] Add the mixture to the hydroxypropyl methylcellulose solution and stir for 60-120 minutes until uniform;

[0071] Perform high-pressure homogenization at 1000-2000 bar for 4-12 minutes to obtain a homogenized emulsion;

[0072] The homogenized emulsion and a gas mixture consisting of isobutane and propane are filled into an aerosol can to obtain the zinc oxide foam of the present invention.

[0073] The zinc oxide foam of the present invention provides excellent UV protection, absorbs skin oils, regulates the skin microenvironment, and aids wound healing. Furthermore, due to its foam formulation, it is easy to use, spreads evenly, leaves no noticeable white residue on the skin, and provides a pleasant sensory experience. In particular, the zinc oxide foam product of the present invention has a low foam density and high foam stability, significantly improving the user experience. DETAILED DESCRIPTION

[0074] A zinc oxide foam comprises the following raw materials in percentage by weight:

[0075] Isobutane: 5-10%;

[0076] Zinc oxide: 3-10%;

[0077] 1,2-Butanediol: 3-10%;

[0078] Polydimethylsiloxane: 3-10%;

[0079] Caprylic / capric triglyceride: 2-10%;

[0080] Stearyl alcohol polyether-21: 2-10%;

[0081] Cetearyl alcohol: 1-5%;

[0082] Glycerol: 1-5%;

[0083] D-panthenol: 1-5%;

[0084] Sunflower seed oil: 1-5%;

[0085] Propane: 1-5%;

[0086] Stearyl alcohol polyether-2: 1-5%;

[0087] Hydroxypropyl methylcellulose: 0.5-3%;

[0088] p-Hydroxyacetophenone: 0.02-0.16%;

[0089] 1,2-Hexanediol: 0.1-0.5%;

[0090] 1,3-Propanediol: 0.1-0.5%;

[0091] Calendula extract: 0.05-0.5%;

[0092] Phenoxyethanol: 0.01-0.12%;

[0093] Methylparaben: 0.01-0.12%;

[0094] The balance is water.

[0095] Preferably, a zinc oxide foam comprises the following raw materials in percentage by weight:

[0096] Isobutane: 6-8%;

[0097] Zinc oxide: 4-6%;

[0098] 1,2-Butanediol: 4-6%;

[0099] Polydimethylsiloxane: 4-6%;

[0100] Caprylic / capric triglyceride: 3-5%;

[0101] Stearyl alcohol polyether-21: 3-5%;

[0102] Cetearyl alcohol: 2-4%;

[0103] Glycerol: 2-4%;

[0104] D-panthenol: 1-3%;

[0105] Sunflower seed oil: 1-3%;

[0106] Propane: 1-3%;

[0107] Stearyl alcohol polyether-2: 1-3%;

[0108] Hydroxypropyl methylcellulose: 0.7-2%;

[0109] p-Hydroxyacetophenone: 0.03-0.08%;

[0110] 1,2-Hexanediol: 0.1-0.3%;

[0111] 1,3-Propanediol: 0.1-0.3%;

[0112] Calendula extract: 0.05-0.2%;

[0113] Phenoxyethanol: 0.02-0.06%;

[0114] Methylparaben: 0.02-0.06%;

[0115] The balance is water.

[0116] In the formula of the present invention, each raw material plays an important role, which is specifically introduced as follows:

[0117] Isobutane: Isobutane is used as a propellant in this product. As a low-boiling alkane, isobutane evaporates quickly. When the product is sprayed, it evaporates quickly, forming bubbles and foam, which carry the other ingredients out of the container. This helps the product evenly coat the skin, providing a comfortable application experience.

[0118] Zinc oxide: Zinc oxide serves multiple purposes in the present invention. First, it has antioxidant properties, helping to reduce free radical damage to the skin and protect it from environmental aggressors. Second, zinc oxide has anti-inflammatory properties, alleviating skin inflammation and allergic reactions, reducing redness, swelling, and irritation. Furthermore, zinc oxide has antimicrobial properties, helping to reduce the growth of bacteria and microorganisms, maintaining healthy skin. It also regulates oil secretion, helping to control shine and keep skin looking fresh. Preferably, the zinc oxide has a particle size of 50-800 nanometers. More preferably, the zinc oxide has a particle size of 100-300 nanometers.

[0119] 1,2-Butanediol: 1,2-Butanediol acts as a humectant in this invention. Due to its unique chemical structure, 1,2-Butanediol is able to attract and retain moisture in the skin, preventing dryness and tightness. Its excellent moisturizing properties increase the skin's hydration capacity, leaving it soft, moisturized, and smooth.

[0120] Dimethicone: Dimethicone's primary function is as a skincare and surface treatment agent, providing a silky texture, increasing product glide, and improving skin feel. Its unique molecular structure allows it to form a highly stable film at the interface between water and oil, helping to protect the skin from environmental aggressors. Additionally, due to its hydrophobic and lipophilic properties, it enhances product water resistance and helps lock in moisture, preventing dryness.

[0121] Caprylic / capric triglyceride: This ingredient acts as a skin conditioning agent and emulsifier in this product. Caprylic / capric triglyceride has good penetrability, gently moisturizing and softening the skin, improving its flexibility and elasticity. Furthermore, as an emulsifier, it facilitates the mixing of the aqueous and oil phases, resulting in a stable product with a pleasant user experience.

[0122] Steareth-21: Steareth-21 is a nonionic surfactant with excellent emulsifying and stabilizing properties. It reduces the surface tension between the aqueous and oil phases, promoting their mixing and forming a stable emulsion. This is crucial for improving the stability and quality of the product.

[0123] Cetearyl Alcohol: In this application, cetearyl alcohol is used as an emulsifier and stabilizer. As an emulsifier, cetearyl alcohol helps the oil and water phases mix, forming a homogeneous emulsion. As a stabilizer, it prevents separation and increases the product's viscosity, making it easier to apply to the skin.

[0124] Glycerin: A powerful humectant, glycerin attracts and retains moisture, preventing moisture loss in the skin. It forms a protective film on the skin's surface, reducing water evaporation and keeping it moisturized and radiant. It also improves skin's softness, flexibility, and elasticity.

[0125] D-Panthenol: D-Panthenol demonstrates significant moisturizing and repairing properties in this product. As a water-soluble vitamin, D-Panthenol penetrates deep into the skin's surface, providing lasting moisture and helping maintain suppleness and elasticity. More importantly, D-Panthenol possesses excellent repair properties, helping to repair skin damage, reduce redness and irritation, and has a significant soothing effect on sensitive skin.

[0126] Sunflower Seed Oil: Sunflower seed oil is a natural plant oil rich in vitamin E and omega-6 fatty acids. In this application, sunflower seed oil effectively nourishes the skin, maintains its water-oil balance, and prevents dryness and roughness. Furthermore, sunflower seed oil's antioxidant properties help protect against free radical damage and slow down skin aging.

[0127] Propane: In this formulation, propane is used as a propellant. It effectively propels the aerosol out of the container, creating a homogeneous, fine foam. Propane's rapid evaporation allows the foam to spread evenly across the skin in a short period of time, providing a comfortable experience.

[0128] Steareth-2: Steareth-2 is a nonionic surfactant that helps stabilize product formulations and enhance their emulsification. In this application, its presence reduces the surface tension between the aqueous and oil phases, allowing these two immiscible components to mix and form a stable emulsion. This is crucial for improving product quality and effectiveness.

[0129] Hydroxypropyl methylcellulose: It is an effective thickener that increases the viscosity of the product, allowing it to better adhere to the skin and form a protective film on the skin. This property makes the formula more evenly distributed on the skin and more effective.

[0130] Parahydroxyacetophenone: In this invention, it serves as a preservative to maintain product quality and extend its effectiveness and shelf life. Preventing microbial growth is crucial in the manufacturing process of skincare products, as this can lead to reduced product quality and even damage the user's skin. Therefore, the use of parahydroxyacetophenone ensures product safety and effectiveness.

[0131] 1,2-Hexanediol: As an effective humectant, 1,2-Hexanediol has a remarkable water-absorbing capacity, capable of attracting and retaining large amounts of water. This property allows it to effectively enhance skin's moisture and elasticity, helping to prevent excessive dryness and dehydration. This is extremely important, as skin moisture balance is key to maintaining healthy and youthful skin. Insufficient moisture can lead to dryness, roughness, and dullness, and even cause skin problems such as dermatitis and acne. In addition to its excellent moisturizing properties, 1,2-Hexanediol also acts as a solvent, helping other ingredients in the product to dissolve and disperse better. This function enables 1,2-Hexanediol to ensure uniformity and stability throughout the entire product formula. Whether it is zinc oxide or other additives, they require the help of a solvent to fully mix together and form a uniform and consistent formulation.

[0132] 1,3-Propanediol: 1,3-Propanediol is widely used in skin care products, primarily as a powerful humectant. It attracts and retains moisture in the skin, increasing its hydration and preventing dryness and tightness. In this invention, the use of 1,3-Propanediol significantly enhances the moisturizing effect of the product, providing users with a long-lasting and comfortable experience.

[0133] Calendula Extract: Calendula extract is a naturally occurring active ingredient with numerous benefits for the skin. In this application, calendula extract provides comprehensive skin protection through its anti-inflammatory, antibacterial, and antioxidant properties. Its anti-inflammatory properties calm the skin, reducing redness, swelling, and itching; its antibacterial properties protect against bacteria and viruses; and its antioxidant properties help fight free radicals, slowing skin aging and enhancing skin vitality.

[0134] Phenoxyethanol: Phenoxyethanol is used as a preservative in this invention. Its primary function is to inhibit microbial growth, thereby maintaining product quality and stability. This is because phenoxyethanol can disrupt microbial cell membranes, preventing their growth and reproduction. Furthermore, phenoxyethanol has good solubility, helping the other ingredients in the formula mix evenly, thereby improving product performance.

[0135] Methylparaben: Methylparaben is a preservative widely used in personal care products. It can effectively inhibit the growth of bacteria and mold, thereby maintaining product stability and extending its shelf life.

[0136] In this invention, water acts as a solvent, blending the ingredients of the formula into a continuous, homogeneous phase, ensuring the overall effectiveness of the product. Furthermore, water provides the foundation for the product's texture and appearance, allowing it to release easily from the container during use and form a comfortable film on the skin.

[0137] The present invention also provides a method for preparing the zinc oxide foam, comprising the following steps:

[0138] Dissolving hydroxypropyl methylcellulose in water to form a hydroxypropyl methylcellulose solution;

[0139] Combine zinc oxide, 1,2-butylene glycol, dimethicone, caprylic / capric triglyceride, steareth-21, cetearyl alcohol, glycerin, D-panthenol, helianthus annuus seed oil, and steareth-2 to form a preliminary mixture;

[0140] Add 1,2-hexanediol, 1,3-propylene glycol, calendula officinalis extract, p-hydroxyacetophenone, phenoxyethanol, and methylparaben to the preliminary mixed solution, stir to obtain a mixture; then add to the hydroxypropyl methylcellulose solution;

[0141] Homogenization;

[0142] Fillable with isobutane and propane.

[0143] Preferably, a method for preparing zinc oxide foam comprises the following steps:

[0144] Dissolve hydroxypropyl methylcellulose in water at room temperature and stir for 2-6 hours to form a hydroxypropyl methylcellulose solution;

[0145] Mix zinc oxide, 1,2-butylene glycol, dimethicone, caprylic / capric triglyceride, steareth 21, cetearyl alcohol, glycerin, D-panthenol, sunflower seed oil, and steareth 2, and stir at 50-70°C for 15-25 minutes until uniform to form a preliminary mixed solution;

[0146] Add 1,2-hexanediol, 1,3-propylene glycol, calendula officinalis extract, p-hydroxyacetophenone, phenoxyethanol, and methylparaben to the preliminary mixed solution, and continue stirring at 50-70° C. for 15-25 minutes to obtain a mixture;

[0147] Add the mixture to the hydroxypropyl methylcellulose solution and stir for 60-120 minutes until uniform;

[0148] Perform high-pressure homogenization at 1000-2000 bar for 4-12 minutes to obtain a homogenized emulsion;

[0149] The homogenized emulsion and a gas mixture consisting of isobutane and propane are filled into an aerosol can to obtain the zinc oxide foam of the present invention.

[0150] Before use, users only need to shake the aerosol can and squeeze it out to get zinc oxide foam. Squeeze out a thumb-sized amount, avoiding the eye and lip areas, and apply a thin layer on the face, or apply it locally on acne / problem skin.

[0151] Specific precautions for this product: 1. This product is pressure-packed and should not be used without impact. Keep away from sources of fire. 2. Store in a dry, ventilated environment below 50°C, away from direct sunlight and heat sources. 3. Keep out of reach of children. 4. Do not puncture the product or empty cans or dispose of them in fire. 5. Avoid contact with eyes and other mucous membranes (such as the mouth). If contact occurs, rinse immediately with plenty of water. 6. Use this product and allow it to dry thoroughly before using other products. 7. A white film may form on the skin after use, which is normal. Storage: Store at room temperature away from light.

[0152] The zinc oxide foam of the present invention has the following advantages:

[0153] (1) Skin Repair: The zinc oxide foam of the present invention can improve sensitive redness caused by various skin problems. This effect is mainly due to the presence of zinc oxide in the formula, which can effectively soothe sensitive skin and control oil secretion, helping to repair the skin.

[0154] (2) Absorbing oil: The foam of the present invention can absorb excess oil on the skin surface, tighten pores, and thus keep the skin dry.

[0155] (3) Multi-part care: This zinc oxide foam is suitable for the care of various skin parts, including hands, armpits and baby's buttocks, and can effectively isolate external stimuli.

[0156] (4) Compounding of multiple soothing ingredients: The foam of the present invention contains multiple soothing ingredients, including D-panthenol, sunflower seed oil, and calendula extract. Among them, D-panthenol can lock in moisture and moisturize the skin to repair the skin barrier; sunflower seed oil can moisturize the skin to maintain water and oil balance; and calendula extract has the effect of calming the skin, maintaining skin stability, and enhancing skin activity.

[0157] The zinc oxide foam product of this invention boasts a low foam density (<0.12g / cm³) and excellent stability, resulting in exceptional performance and user experience. The low-density foam feels light and fluffy, making it easy to apply and significantly enhancing the user experience. Furthermore, it can cover a larger area with the same mass, making it particularly suitable for large-scale applications such as skin protection or wound treatment. Its high stability means it forms a long-lasting protective layer on the skin, protecting it from UV rays and pollutants. Furthermore, zinc oxide's antibacterial and anti-inflammatory properties help reduce inflammation and promote skin healing. The stable foam structure also ensures an even and comfortable application process, enhancing the user experience.

[0158] In order to further reduce the foam density of zinc oxide foam products and improve foam stability, the inventors considered from multiple angles, such as polysaccharides or polymers can be used as foam stabilizers to increase foam stability; for example, the optimization of surfactants.

[0159] Specifically, the inventors concluded through a large number of experiments that replacing steareth-21 in the initial formula with lauryl glucoside can indeed reduce the foam density of the zinc oxide foam product and improve the foam stability.

[0160] Specifically, a zinc oxide foam includes the following raw materials in percentage by weight:

[0161] Isobutane: 6-8%;

[0162] Zinc oxide: 4-6%;

[0163] 1,2-Butanediol: 4-6%;

[0164] Polydimethylsiloxane: 4-6%;

[0165] Caprylic / capric triglyceride: 3-5%;

[0166] Dodecyl glucoside: 3-5%;

[0167] Cetearyl alcohol: 2-4%;

[0168] Glycerol: 2-4%;

[0169] D-panthenol: 1-3%;

[0170] Sunflower seed oil: 1-3%;

[0171] Propane: 1-3%;

[0172] Stearyl alcohol polyether-2: 1-3%;

[0173] Hydroxypropyl methylcellulose: 0.7-2%;

[0174] p-Hydroxyacetophenone: 0.03-0.08%;

[0175] 1,2-Hexanediol: 0.1-0.3%;

[0176] 1,3-Propanediol: 0.1-0.3%;

[0177] Calendula extract: 0.05-0.2%;

[0178] Phenoxyethanol: 0.02-0.06%;

[0179] Methylparaben: 0.02-0.06%;

[0180] The balance is water.

[0181] In the embodiment: Calendula officinalis extract, specification: Calendula officinalis powder 10:1 / kg, item number: NB9635412.

[0182] In the examples, unless otherwise specified, all raw materials are calculated based on 100% effective content. Example 1

[0183] A zinc oxide foam comprises the following raw materials in percentage by weight:

[0184] Isobutane: 7%;

[0185] Zinc oxide (particle size 100 nm): 5%;

[0186] 1,2-Butanediol: 5%;

[0187] Polydimethylsiloxane: 5%;

[0188] Caprylic / capric triglyceride: 4%;

[0189] Stearyl alcohol polyether-21: 4%;

[0190] Cetearyl alcohol: 3%;

[0191] Glycerol: 3%;

[0192] D-panthenol: 2%;

[0193] Sunflower seed oil: 2%;

[0194] Propane: 2%;

[0195] Stearyl alcohol polyether-2: 2%;

[0196] Hydroxypropyl methylcellulose: 1%;

[0197] p-Hydroxyacetophenone: 0.06%;

[0198] 1,2-Hexanediol: 0.2%;

[0199] 1,3-Propanediol: 0.2%;

[0200] Calendula officinalis flower extract: 0.1%;

[0201] Phenoxyethanol: 0.04%;

[0202] Methylparaben: 0.04%;

[0203] The balance is water.

[0204] The preparation method of the zinc oxide foam comprises the following steps:

[0205] At room temperature, hydroxypropyl methylcellulose was dissolved in water, stirred at 500 rpm for 4 hours, and allowed to stand for 24 hours to form a hydroxypropyl methylcellulose solution;

[0206] Mix zinc oxide, 1,2-butylene glycol, dimethicone, caprylic / capric triglyceride, steareth-21, cetearyl alcohol, glycerin, D-panthenol, helianthus annuus seed oil, and steareth-2, and stir at 60°C and 500 rpm for 20 minutes until uniform to form a preliminary mixed solution;

[0207] 1,2-hexanediol, 1,3-propylene glycol, calendula officinalis extract, p-hydroxyacetophenone, phenoxyethanol, and methylparaben were added to the preliminary mixed solution, and the mixture was stirred at 500 rpm for 20 minutes at 60° C. to obtain a mixture;

[0208] The mixture was added to the hydroxypropyl methylcellulose solution and stirred at 700 rpm for 90 minutes until homogeneous;

[0209] Homogenization was performed under high pressure (1500 bar) for 8 minutes to obtain a homogenized emulsion;

[0210] The homogenized emulsion and a gas mixture consisting of isobutane and propane are filled into an aerosol can, and the pressure in the can is controlled to be 0.4 MPa to obtain the zinc oxide foam of the present invention. Example 2

[0211] The only difference between Example 2 and Example 1 is that the particle size of the zinc oxide used is 50 nanometers. Example 3

[0212] The only difference between Example 3 and Example 1 is that the particle size of the zinc oxide used is 300 nanometers. Example 4

[0213] The only difference between Example 4 and Example 1 is that the particle size of the zinc oxide used is 800 nanometers. Example 5

[0214] The only difference between Example 5 and Example 1 is that "stearyl alcohol polyether-21: 4%" is replaced by "lauryl glucoside: 4%". Example 6

[0215] The only difference between Example 6 and Example 1 is that "steareth-21: 4% and steareth-2: 2%" is replaced by "lauryl glucoside: 6%". Example 7

[0216] The only difference between Example 7 and Example 1 is that "steareth-21: 4% and steareth-2: 2%" is replaced by "steareth-2: 6%". Comparative Example 1

[0217] A cosmetic foam comprising the following raw materials in percentage by weight:

[0218] Isobutane: 7%;

[0219] 1,2-Butanediol: 5%;

[0220] Polydimethylsiloxane: 5%;

[0221] Caprylic / capric triglyceride: 4%;

[0222] Stearyl alcohol polyether-21: 4%;

[0223] Cetearyl alcohol: 3%;

[0224] Glycerol: 3%;

[0225] D-panthenol: 2%;

[0226] Sunflower seed oil: 2%;

[0227] Propane: 2%;

[0228] Stearyl alcohol polyether-2: 2%;

[0229] Hydroxypropyl methylcellulose: 1%;

[0230] p-Hydroxyacetophenone: 0.06%;

[0231] 1,2-Hexanediol: 0.2%;

[0232] 1,3-Propanediol: 0.2%;

[0233] Calendula officinalis flower extract: 0.1%;

[0234] Phenoxyethanol: 0.04%;

[0235] Methylparaben: 0.04%;

[0236] The balance is water.

[0237] The preparation method of the zinc oxide foam comprises the following steps:

[0238] At room temperature, hydroxypropyl methylcellulose was dissolved in water, stirred at 500 rpm for 4 hours, and allowed to stand for 24 hours to form a hydroxypropyl methylcellulose solution;

[0239] Mix 1,2-butylene glycol, dimethicone, caprylic / capric triglyceride, steareth-21, cetearyl alcohol, glycerin, D-panthenol, helianthus annuus seed oil, and steareth-2, and stir at 60°C and 500 rpm for 20 minutes until uniform to form a preliminary mixed solution;

[0240] 1,2-hexanediol, 1,3-propylene glycol, calendula officinalis extract, p-hydroxyacetophenone, phenoxyethanol, and methylparaben were added to the preliminary mixed solution, and the mixture was stirred at 500 rpm for 20 minutes at 60° C. to obtain a mixture;

[0241] The mixture was added to the hydroxypropyl methylcellulose solution and stirred at 700 rpm for 90 minutes until homogeneous;

[0242] Homogenization was performed under high pressure (1500 bar) for 8 minutes to obtain a homogenized emulsion;

[0243] The homogenized emulsion and a gas mixture of isobutane and propane were filled into an aerosol can and the pressure in the can was controlled to be 0.4 MPa.

[0244] Test Example 1: Foam density and stability test

[0245] Prepare a transparent cylindrical glass with an inner diameter of 50 mm and a height of 100 mm. Weigh the mass A1 (g) of the empty glass.

[0246] At an ambient temperature of 25°C, gently shake the aerosol can and press the zinc oxide foam into the glass to fill the entire glass, trying to avoid the generation of air bubbles during the filling process.

[0247] Let the filled glass sit for 10 seconds to allow the foam to fully expand. Then, clean off the foam from the top of the glass. Weigh the mass of the foam-filled glass (A2, g).

[0248] V = πr²h = π×(2.5cm)²×10cm = 196.35 cm³

[0249] Foam density ρ = (A2- A1) / 196.35 g / cm³

[0250] The mixture is allowed to stand for another 10 minutes at an ambient temperature of 25°C, at which time the foam height Y (in mm) in the glass is observed and measured.

[0251] Calculate the foam stability rate X using the following formula: X = Y / 100 × 100%.

[0252] If the calculated foam stability rate X is greater than 80%, the zinc oxide foam product is considered to have excellent foam stability.

[0253] Table 1 Stability test results

[0254] Foam stability rate X, % Foam density, g / cm³ Example 1 87 0.095 Example 2 65 0.112 Example 3 89 0.102 Example 4 68 0.115 Example 5 93 0.082 Example 6 90 0.104 Example 7 82 0.109 Comparative Example 1 99 0.058

[0255] In this application, foam density and foam stability are two independent but highly important properties. They both significantly impact product performance and user experience, but there's no direct causal relationship. Foam stability determines how long the foam lasts after formation and whether it easily breaks when subjected to external forces. Foam density, on the other hand, is primarily influenced by factors such as the properties and proportions of the liquid ingredients in the formula, as well as the method of foam generation. It impacts the foam's feel and coverage, as well as the product's effectiveness.

[0256] The zinc oxide foam product of the present invention has a low foam density (<0.12g / cm³). This low foam density is of great significance to the performance and user experience of the product:

[0257] (1) Optimize product experience: Lower foam density means the product has a lighter and fluffier texture, which can be easily applied during use, giving users a better experience.

[0258] (2) Improved coverage: Lower foam density also means that with the same mass, the foam can cover a larger area, which is very beneficial for situations where a large area needs to be used, such as in skin protection, wound treatment and other applications.

[0259] The zinc oxide foam product of the present invention has excellent foam stability. This means:

[0260] (1) Long-lasting protection: The high stability of zinc oxide foam means that it does not dissipate or break down quickly after application to the skin. This stability ensures that it can remain on the skin's surface for a long time, forming a stable protective layer. This is crucial for protecting the skin from UV rays, pollutants, or other factors that may cause skin diseases. In addition, because zinc oxide itself has good antibacterial and anti-inflammatory properties, this stable foam layer can also help reduce the risk of skin inflammation and promote the skin's natural healing process.

[0261] (2) Improved user experience: A highly stable zinc oxide foam product feels more comfortable when used. Because the foam has good stability, it does not immediately break or dissipate when applied to the skin, making the product easier to apply and can be evenly applied to the required area. In addition, the texture of the foam is lighter than that of ordinary liquid products, and it feels softer and more comfortable on the skin. This feeling can enhance the user experience and make them more willing to use this product regularly to protect their skin.

[0262] Furthermore, comparing Control Example 1 with Example 1 reveals that the only difference lies in the presence of zinc oxide. Foam stability testing revealed that the addition of a certain amount (4-6%) of zinc oxide significantly decreased foam stability. Zinc oxide, as a particulate solid, may interfere with foam stability. More specifically, these solid particles may damage the foam film, making the foam more susceptible to collapse.

[0263] In addition, the addition of zinc oxide may also affect the surfactants in the foam, affecting their arrangement and stability on the liquid film surface, further reducing the stability of the foam. Therefore, based on the experimental results and these possible mechanisms, we can conclude that the addition of zinc oxide will lead to a decrease in foam stability.

[0264] Furthermore, when zinc oxide is added to the formulation, particles with a particle size between 100 and 300 nanometers are likely to be well distributed within the liquid film, minimizing disruption. Small particles (e.g., 50 nanometers) may aggregate more easily, leading to localized destabilization of the liquid film. Larger particles (e.g., 800 nanometers) may be too large, compromising the integrity of the liquid film and, consequently, the stability of the foam. Variations in zinc oxide particle size may affect its interaction with surfactants. At smaller (e.g., 50 nanometers) or larger (e.g., 800 nanometers) particle sizes, zinc oxide may more strongly adsorb surfactants, altering the surfactant's arrangement on the liquid film surface and further impacting foam stability. Zinc oxide particle size may also affect its distribution within the foam. Ideally, we want zinc oxide to be evenly distributed throughout the foam. Smaller (e.g., 50 nanometers) particles may aggregate, resulting in uneven distribution, while larger (e.g., 800 nanometers) particles may be too large, compromising their distribution within the foam. Therefore, taking all the above factors into consideration, we can conclude that within the particle size range of 100-300 nanometers, the impact of zinc oxide is likely to be relatively small, resulting in better foam stability. The data comparison of the test case also effectively verifies the above view.

[0265] For Example 5, steareth-2 and lauryl glucoside may form a special complementary structure in the liquid, which allows them to jointly reduce the surface tension of the liquid, thereby increasing the stability of the foam. In addition, this combination of steareth-2 and lauryl glucoside may also improve the density of the foam. When a surfactant forms foam in a liquid, the density of the foam depends mainly on the mass of the liquid and the volume of the foam. If the combination of the two surfactants can form a larger volume of foam, then under the same mass of liquid, the density of the foam will be reduced accordingly. In general, steareth-2 and lauryl glucoside may form a synergistic effect to a certain extent, jointly improving the stability of the foam and reducing the foam density. However, this is merely a theoretical explanation, and the exact mechanism may still require further experimental verification.

[0266] Test Example 2:

[0267] Conventional data testing was performed on Example 1:

[0268] Table 2 Conventional test results of zinc oxide foam

[0269] Inspection items index Measured data Total colony count CFU / g ≤1000 CFU / g 300 CFU / g Total number of molds and yeasts CFU / g <100 CFU / g 20 CFU / g Thermotolerant coliform bacteria / g Not to be detected 0 Staphylococcus aureus / g Not to be detected 0 Pseudomonas aeruginosa / g Not to be detected 0 Lead mg / kg ≤10 mg / kg 0 Arsenic mg / kg ≤2 mg / kg 0 Mercury mg / kg ≤1 mg / kg 0 Cadmium mg / kg ≤5 mg / kg 0 Dioxane mg / kg ≤30 mg / kg 10 mg / kg

Claims

1. A zinc oxide foam comprising the following raw materials in percentage by weight: Isobutane: 6-8%; Zinc oxide: 4-6%; 1,2-Butanediol: 4-6%; Polydimethylsiloxane: 4-6%; Caprylic / capric triglyceride: 3-5%; Dodecyl glucoside: 3-5%; Cetearyl alcohol: 2-4%; Glycerol: 2-4%; D-panthenol: 1-3%; Sunflower seed oil: 1-3%; Propane: 1-3%; Stearyl alcohol polyether-2: 1-3%; Hydroxypropyl methylcellulose: 0.7-2%; p-Hydroxyacetophenone: 0.03-0.08%; 1,2-Hexanediol: 0.1-0.3%; 1,3-Propanediol: 0.1-0.3%; Calendula extract: 0.05-0.2%; Phenoxyethanol: 0.02-0.06%; Methylparaben: 0.02-0.06%; The balance is water; The particle size of zinc oxide is in the range of 100-300 nanometers.