CN116850071B

CN116850071B - Zinc oxide foam and preparation method thereof

Info

Publication number: CN116850071B
Application number: CN202310938316.4A
Authority: CN
Inventors: 蔡蓓蕾; 冯杰; 朱佳彬; 王跃
Original assignee: Wuxi Zhiyan Biotechnology Co ltd
Current assignee: Wuxi Zhiyan Biotechnology Co ltd
Priority date: 2023-07-28
Filing date: 2023-07-28
Publication date: 2025-09-02
Anticipated expiration: 2043-07-28
Also published as: CN116850071A

Abstract

The invention relates to the technical field of zinc oxide foam, and provides zinc oxide foam and a preparation method thereof. The zinc oxide foam comprises the following raw materials of isobutane, zinc oxide, 1, 2-butanediol, polydimethylsiloxane, caprylic/capric triglyceride, stearyl alcohol polyether-21, cetostearyl alcohol, glycerol, D-panthenol, sunflower seed oil, propane, stearyl alcohol polyether-2, hydroxypropyl methyl cellulose, p-hydroxyacetophenone, 1, 2-hexanediol, 1, 3-propanediol, calendula extract, phenoxyethanol, methylparaben and water. The zinc oxide foam has lower foam density and higher foam stability, has good ultraviolet protection effect, can absorb skin grease, regulate skin microenvironment and is beneficial to wound healing. At the same time, due to the nature of its foam formulation, it is possible to achieve ease of use, uniform distribution, no significant white residue left on the skin, and a pleasant sensory experience.

Description

Zinc oxide foam and preparation method thereof

Technical Field

The invention relates to the technical field of zinc oxide foam, and particularly provides zinc oxide foam and a preparation method thereof.

Background

Zinc oxide is widely used in many personal care products including sunscreens, prickly heat powder, baby poems, facial masks, and the like. Its main functions are to provide UV protection, absorb grease and moisture, regulate skin microenvironment, and facilitate wound healing. In addition, zinc oxide has been found to have a positive effect on combating skin infections, and to inhibit the growth of skin pathogens such as staphylococcus aureus and candida albicans.

Although the numerous advantages of zinc oxide in skin care and protection are widely recognized by a wide range of users and professionals, in practice we have found that there are some significant limitations. In conventional zinc oxide products, common forms such as paste, emulsion and the like have some effects in treating and protecting skin, but some problems caused during use cause users to be affected in use experience, especially in terms of appearance and convenience.

First, these conventional zinc oxide formulations tend to leave a noticeable white residue on the skin. This phenomenon is mainly due to the physical properties of the zinc oxide itself, i.e. the zinc oxide particles form a visible white coating when applied to the skin. This problem can cause significant inconvenience to the user during social interaction and daily activities, especially when the user needs to use the zinc oxide product on the face or other conspicuous locations. The presence of such white residues may affect the user's self-confidence, so as to affect their daily life and social activities. Thus, although zinc oxide has excellent skin care effects, such undesirable appearance effects have prevented the widespread use and acceptance of zinc oxide products to some extent.

Second, these conventional methods of application of zinc oxide formulations typically involve direct application with a finger or cotton swab or like implement, which can result in uneven distribution of the product on the skin. Uneven distribution may not only affect the effect of the product, but may also cause excessive smearing in some places and insufficient smearing in other places, so that the protection effect of zinc oxide cannot be fully exerted. Moreover, the cleaning condition of the hands has an influence on the effect of the product, and if the hands are polluted, dirt can be brought into the product, so that the cleanliness and stability of the product are affected.

Therefore, it becomes important to develop a new zinc oxide product to solve the above-mentioned problems. The ideal novel product should be easy to use, be able to be evenly distributed on the skin, leave no significant white residue, and at the same time take full advantage of the various advantages of zinc oxide.

In recent years, foam-type products have become increasingly popular in various personal care products, including cleaning products, skin care products, and hair care products, among others. Foam-dosage products have many advantages, such as ease of use, ability to be evenly distributed, a pleasant sensory experience, etc. However, to date, there has been no report of developing zinc oxide products using such dosage forms.

Accordingly, there is an urgent need to develop a novel zinc oxide foam product to fully utilize various advantages of zinc oxide while avoiding the disadvantages of conventional zinc oxide products. Furthermore, the novel product should be convenient to use, be able to be evenly distributed on the skin, leave no white residue, while providing a pleasant sensory experience.

Disclosure of Invention

Aiming at the defects existing in the prior art, the invention provides zinc oxide foam and a preparation method thereof.

The invention provides a zinc oxide foam, which comprises zinc oxide and a propellant, wherein the propellant is isobutane and/or propane. The zinc oxide foam product can provide skin protection, ultraviolet injury prevention and can also generate a foam form which is convenient to use through a specific propellant.

Preferably, the zinc oxide foam further comprises a humectant, wherein the humectant is at least one of 1, 2-butanediol, glycerol, D-panthenol, betaine, sodium hyaluronate, urea, trehalose, tremella polysaccharide, dextran, 1, 2-hexanediol and 1, 3-propanediol.

Preferably, the zinc oxide foam further comprises a preservative, wherein the preservative is at least one of phenoxyethanol, p-hydroxyacetophenone, ethylhexyl glycerol, sodium benzoate, octyl glycerol and methylparaben.

Preferably, the zinc oxide foam further comprises an emulsifier, wherein the emulsifier is at least one of stearyl polyether-21, stearyl polyether-2, sodium stearyl glutamate, potassium cetyl phosphate, glycerol stearate, sucrose stearate, cetostearyl glucoside, cetostearyl polyether-20, PEG-100 stearate, fatty acid, and tween 60.

Preferably, the zinc oxide foam further comprises a thickener, wherein the thickener is at least one of carbomer, xanthan gum, sphingomonas fermentation extract, microcrystalline cellulose, cellulose gum, cyclodextrin, polyacrylate crosslinked polymer-6, ammonium acryloyldimethyl taurate/VP copolymer and hydroxypropyl methyl cellulose.

Preferably, the zinc oxide foam further comprises grease, wherein the grease 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 dioctyl carbonate.

Preferably, the zinc oxide foam comprises the following raw materials of isobutane, zinc oxide, 1, 2-butanediol, polydimethylsiloxane, caprylic/capric triglyceride, stearyl alcohol polyether-21, cetostearyl alcohol, glycerol, D-panthenol, sunflower seed oil, propane, stearyl alcohol polyether-2, hydroxypropyl methylcellulose, p-hydroxyacetophenone, 1, 2-hexanediol, 1, 3-propanediol, calendula extract, phenoxyethanol, methylparaben and water.

The invention provides zinc oxide foam which comprises the following raw materials of isobutane, zinc oxide, 1, 2-butanediol, polydimethylsiloxane, caprylic/capric triglyceride, stearyl alcohol polyether-21, cetostearyl alcohol, glycerol, D-panthenol, sunflower seed oil, propane, stearyl alcohol polyether-2, hydroxypropyl methyl cellulose, p-hydroxyacetophenone, 1, 2-hexanediol, 1, 3-propanediol, calendula extract, phenoxyethanol, hydroxybenzoate and water.

Preferably, the zinc oxide foam comprises the following raw materials in percentage by mass:

5-10% of isobutane;

3-10% of zinc oxide;

3-10% of 1, 2-butanediol;

3-10% of polydimethylsiloxane;

2-10% of caprylic/capric triglyceride;

Stearyl alcohol polyether-21:2-10%;

Cetostearyl alcohol 1-5%;

Glycerol 1-5%;

1-5% of D-panthenol;

1-5% of sunflower seed oil;

1-5% of propane;

Stearyl alcohol polyether-2:1-5%;

0.5-3% of hydroxypropyl methyl cellulose;

0.02-0.16% of p-hydroxyacetophenone;

0.1-0.5% of 1, 2-hexanediol;

0.1-0.5% of 1, 3-propylene glycol;

0.05-0.5% of calendula extract;

0.01 to 0.12 percent of phenoxyethanol;

0.01 to 0.12 percent of methylparaben;

The balance being water.

6-8% of isobutane;

4-6% of zinc oxide;

4-6% of 1, 2-butanediol;

4-6% of polydimethylsiloxane;

3-5% of caprylic/capric triglyceride;

3-5% of stearyl alcohol polyether-21:3;

2-4% of cetylstearyl alcohol;

2-4% of glycerol;

1-3% of D-panthenol;

1-3% of sunflower seed oil;

1-3% of propane;

stearyl alcohol polyether-2:1-3%;

0.7-2% of hydroxypropyl methyl cellulose;

0.03-0.08% of p-hydroxyacetophenone;

0.1-0.3% of 1, 2-hexanediol;

0.1-0.3% of 1, 3-propylene glycol;

0.05-0.2% of calendula extract;

0.02-0.06% of phenoxyethanol;

0.02-0.06% of methylparaben;

The balance being water.

The invention also provides a preparation method of the zinc oxide foam, which comprises the following steps:

dissolving hydroxypropyl methylcellulose in water to form a hydroxypropyl methylcellulose solution;

Mixing zinc oxide, 1, 2-butanediol, polydimethylsiloxane, caprylic/capric triglyceride, stearyl alcohol polyether-21, cetostearyl alcohol, glycerol, D-panthenol, sunflower seed oil and stearyl alcohol polyether-2 to form a primary mixed solution;

Adding 1, 2-hexanediol, 1, 3-propanediol, calendula extract, p-hydroxyacetophenone, phenoxyethanol and methylparaben into the primary mixed solution, stirring to obtain a mixture, and then adding into hydroxypropyl methylcellulose solution;

Homogenizing;

filling with isobutane and propane.

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

dissolving hydroxypropyl methylcellulose in water at room temperature, and stirring for 2-6 hours to form hydroxypropyl methylcellulose solution;

Zinc oxide, 1, 2-butanediol, polydimethylsiloxane, caprylic/capric triglyceride, stearyl alcohol polyether-21, cetostearyl alcohol, glycerol, D-panthenol, sunflower seed oil and stearyl alcohol polyether-2 are mixed, and stirred for 15-25 minutes to be uniform at 50-70 ℃ to form a primary mixed solution;

Adding 1, 2-hexanediol, 1, 3-propanediol, calendula extract, p-hydroxyacetophenone, phenoxyethanol and methylparaben into the primary mixed solution, and continuously stirring for 15-25 minutes at 50-70 ℃ to obtain a mixture;

adding the mixture into hydroxypropyl methyl cellulose solution, stirring for 60-120 min until uniform;

Homogenizing at 1000-2000 bar under high pressure for 4-12 min to obtain homogenized emulsion;

The homogenized emulsion is filled into an aerosol can together with a gas mixture composed of isobutane and propane, and the zinc oxide foam is obtained.

The zinc oxide foam has good ultraviolet protection effect, can absorb skin grease, regulate skin microenvironment and is beneficial to wound healing. At the same time, due to the nature of its foam formulation, it is possible to achieve ease of use, uniform distribution, no significant white residue left on the skin, and a pleasant sensory experience. In particular, the zinc oxide foam product has lower foam density and higher foam stability, and greatly improves the use experience of customers.

Detailed Description

The zinc oxide foam comprises the following raw materials in percentage by mass:

5-10% of isobutane;

3-10% of zinc oxide;

3-10% of 1, 2-butanediol;

3-10% of polydimethylsiloxane;

2-10% of caprylic/capric triglyceride;

Stearyl alcohol polyether-21:2-10%;

Cetostearyl alcohol 1-5%;

Glycerol 1-5%;

1-5% of D-panthenol;

1-5% of sunflower seed oil;

1-5% of propane;

Stearyl alcohol polyether-2:1-5%;

0.5-3% of hydroxypropyl methyl cellulose;

0.02-0.16% of p-hydroxyacetophenone;

0.1-0.5% of 1, 2-hexanediol;

0.1-0.5% of 1, 3-propylene glycol;

0.05-0.5% of calendula extract;

0.01 to 0.12 percent of phenoxyethanol;

0.01 to 0.12 percent of methylparaben;

The balance being water.

6-8% of isobutane;

4-6% of zinc oxide;

4-6% of 1, 2-butanediol;

4-6% of polydimethylsiloxane;

3-5% of caprylic/capric triglyceride;

3-5% of stearyl alcohol polyether-21:3;

2-4% of cetylstearyl alcohol;

2-4% of glycerol;

1-3% of D-panthenol;

1-3% of sunflower seed oil;

1-3% of propane;

stearyl alcohol polyether-2:1-3%;

0.7-2% of hydroxypropyl methyl cellulose;

0.03-0.08% of p-hydroxyacetophenone;

0.1-0.3% of 1, 2-hexanediol;

0.1-0.3% of 1, 3-propylene glycol;

0.05-0.2% of calendula extract;

0.02-0.06% of phenoxyethanol;

0.02-0.06% of methylparaben;

The balance being water.

In the formula of the invention, the raw materials play an important role, and are specifically introduced as follows:

Isobutane is used as propellant in the present invention. Isobutane, a low boiling alkane, has the property of fast evaporation. When the product is sprayed out, the isobutane evaporates quickly, forming bubbles and foam, and carrying the other ingredients out of the container. This helps the product to evenly cover the skin surface, providing a comfortable use experience.

Zinc oxide has a number of roles in the present invention. First, it has antioxidant properties, helping to reduce the damage of free radicals to the skin and protecting the skin from environmental attack. Secondly, zinc oxide has anti-inflammatory effect, can relieve skin inflammation and sensitive reaction, and reduces red swelling and irritation. In addition, zinc oxide has antibacterial property, and is helpful for reducing the growth of bacteria and microorganisms and maintaining the health state of skin. It can also regulate the secretion of oil from skin, help control the oil and light, and keep the skin fresh. Preferably, the zinc oxide has a particle size of 50-800 nanometers. More preferably, the zinc oxide has a particle size of 100 to 300 nanometers.

1, 2-Butanediol plays a role as a humectant in the present invention. Because of its unique chemical structure, 1, 2-butanediol is capable of absorbing and retaining skin moisture, preventing skin dryness and tightness. It has good moisture keeping ability, and can increase the hydration ability of skin, and keep skin soft, moist and smooth.

Polydimethylsiloxane the main function of polydimethylsiloxane is to provide a silky texture as a skin care and surface treatment agent, increase the slip properties of the product and improve the feel of the skin. Its unique molecular structure allows it to form a very stable film at the interface of water and oil, which helps protect the skin from environmental factors. In addition, it can improve the water resistance of the product due to its hydrophobicity and lipophilicity, and helps to lock the moisture of the skin, preventing the skin from drying out.

Caprylic/capric triglyceride this component acts as a skin conditioner and emulsifier in the present invention. The caprylic/capric triglyceride has good permeability, can gently moisten and soften skin, and improves the flexibility and elasticity of the skin. Furthermore, as an emulsifier, it aids in the mixing of the aqueous and oil phase components, resulting in a stable quality and good use experience of the final product.

Stearyl alcohol polyether-21 is a nonionic surfactant with good emulsifying and stabilizing properties. It can reduce the surface tension between the water phase and the oil phase, promote their mixing and form stable emulsion. This is important to improve the stability and quality of the product of the invention.

Cetostearyl alcohol in the present invention cetostearyl alcohol is used as an emulsifier and stabilizer. As an emulsifier, cetostearyl alcohol can aid in mixing the oil and water phase components to form a homogeneous emulsion. As a stabilizer, it prevents the emulsion from separating, increasing the viscosity of the product, making it easier to apply on the skin.

Glycerol is a powerful humectant that attracts and retains moisture and prevents loss of skin moisture. The glycerol can form a protective film on the surface of skin, so that the evaporation of water is reduced, and the skin is kept moist and glossy. Meanwhile, the glycerol can improve the softness of the skin and improve the flexibility and elasticity of the skin.

D-panthenol exerts remarkable moisturizing and repairing effects in the invention. As a water-soluble vitamin, D-panthenol can penetrate deep into the surface layer of the skin, provide durable moisture to the skin, and help maintain softness and elasticity of the skin. More importantly, the D-panthenol has good repairing function, can help repair skin injury, reduces skin redness and swelling and irritation, and has obvious relieving effect on sensitive skin.

Sunflower seed oil is a natural vegetable oil rich in vitamin E and Omega-6 fatty acids. In the invention, the sunflower seed oil can effectively nourish the skin, keep the water-oil balance of the skin and prevent the skin from being dry and rough. In addition, the antioxidant property of sunflower seed oil helps to resist free radical attack and retard skin aging.

Propane in the formulation according to the invention, propane is used as propellant. The aerosol can be effectively driven out of the container to form uniform and fine foam. Propane has the characteristic of rapid evaporation, allowing the foam to spread evenly across the skin surface in a short period of time, providing a comfortable use experience.

Stearyl alcohol polyether-2 is a nonionic surfactant that helps stabilize the product formulation and increases its emulsifying effect. In the present invention, its presence reduces the surface tension between the aqueous and oil phases, allowing the two mutually insoluble components to mix to form a stable emulsion. This is important to improve the quality and the use effect of the product.

Hydroxypropyl methylcellulose is an effective thickener that increases the viscosity of the product, allows it to adhere better to the skin, and forms a protective film on the skin. This property makes the formulation more evenly distributed over the skin and more effective.

P-hydroxyacetophenone is used as preservative in the invention to maintain the quality of the product and prolong the effectiveness and shelf life of the product. Prevention of microbial growth is critical in the manufacture of skin care products, as microbial growth can lead to reduced product quality and even damage to the skin of the user. Therefore, the use of the hydroxyacetophenone provides guarantee for keeping the safety and the effectiveness of the product.

1, 2-Hexanediol as an effective humectant, 1, 2-hexanediol has a remarkable moisture absorbing ability, and can adsorb and retain a large amount of moisture. This property makes it possible to effectively enhance the moisturization and elasticity of the skin, helping to prevent excessive dryness and dehydration of the skin. This is extremely important because the moisture balance of the skin is a key factor in maintaining skin health and youthfulness. If the skin is insufficiently moist, it may result in dry, rough, matt skin, and even cause skin problems such as dermatitis, acne, etc. In addition to excellent moisturizing effect, 1, 2-hexanediol also acts as a solvent to help better dissolve and disperse other ingredients in the product. This function enables 1, 2-hexanediol to ensure uniformity and stability of the overall product formulation. Both zinc oxide and other additives need to be thoroughly mixed together by the action of the solvent to form a uniform and consistent formulation.

1, 3-Propanediol is widely used in skin care products, mainly as a powerful moisturizer. It can adsorb and retain skin moisture, improve skin moisture content, and prevent skin dryness and tightness. In the invention, the use of the 1, 3-propanediol greatly enhances the moisturizing effect of the product and brings lasting and comfortable use feeling to users.

Calendula extract-calendula extract is a natural active ingredient that has several benefits to the skin. In the present invention, calendula extract provides overall protection to the skin by its anti-inflammatory, antibacterial and antioxidant functions. The anti-inflammatory effect can calm the skin, relieve skin redness, swelling and itching, protect the skin from bacteria and viruses, and resist free radicals, delay skin aging and promote skin activity.

Phenoxyethanol the phenoxyethanol is used as a preservative in the invention and has the main function of inhibiting the growth of microorganisms so as to maintain the quality and stability of the product. This is because phenoxyethanol can destroy the cell membrane of microorganisms and prevent their growth and reproduction. In addition, the phenoxyethanol also has good solubility, and can help other components in the formula to be uniformly mixed, so that the performance of the product is improved.

Methylparaben is a preservative widely used in personal care products. It can effectively inhibit the growth of bacteria and mould, so as to maintain the stability of product and prolong its storage life.

In the present invention, water is used as a solvent to mix the ingredients of the formulation together to form a continuous, uniform phase, thereby ensuring the overall effect of the product. In addition, water also provides a basis for the texture and appearance of the product, allowing the product to be easily released from the container during use and form a comfortable film on the skin.

Homogenizing;

filling with isobutane and propane.

Zinc oxide, 1, 2-butanediol, polydimethylsiloxane, caprylic/capric triglyceride, stearyl polyether 21, cetostearyl alcohol, glycerol, D-panthenol, sunflower seed oil and stearyl polyether 2 are mixed, and stirred for 15-25 minutes to be uniform at 50-70 ℃ to form a primary mixed solution;

Before use, the user can obtain zinc oxide foam by simply shaking the aerosol can and extruding the zinc oxide foam, and the zinc oxide foam is extruded by the size of the thumb to avoid the eyes and lips, and the zinc oxide foam is coated on the face in a thin layer or is coated on the part with acnes/problem skin locally.

The invention has the specific attention points that 1, the invention is packaged under pressure and cannot be impacted and is used far from a fire source, 2, the invention is stored in a dry ventilation environment below 50 ℃ to avoid direct sun exposure and far from the fire source and the heat source, 3, the invention is not placed everywhere by children, 4, the product and an empty pot which is used up do not puncture and put into fire, 5, the invention avoids contacting eyes and other mucous membranes (such as oral cavity and the like) and is immediately rinsed with a large amount of clean water if the product is carelessly touched, 6, the product is used after being used and thoroughly dried, and 7, a white layer of film is formed on the surface of skin after being used, which belongs to the normal phenomenon. The storage condition is that the light is protected at normal temperature.

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

(1) The zinc oxide foam can improve sensitive redness caused by various skin problems. The effect is mainly that the formula contains zinc oxide, so that the sensitive skin can be effectively relaxed, the secretion of grease can be controlled, and the skin can be restored.

(2) The foam of the invention can adsorb superfluous grease on the skin surface and astringe pores, thereby keeping the skin dry and comfortable.

(3) The zinc oxide foam is suitable for nursing various skin parts, including hands, armpits and buttocks of babies, and can effectively isolate external stimulus.

(4) The foam contains a plurality of relieving components, including D-panthenol, sunflower seed oil and calendula extract. Wherein, the D-panthenol can lock water, keep moisture and repair skin barrier, the sunflower seed oil can moisten skin to keep water-oil balance, and the calendula extract has the effects of calming skin, maintaining and stabilizing skin and enhancing skin activity.

The zinc oxide foam products of the present invention, which have low foam density (< 0.12g/cm 3) and excellent stability, impart excellent properties and feel to the product. The foam with low density is light and fluffy in feel, easy to apply, and greatly improves the use experience, and meanwhile, the foam can cover a larger area under the same quality, so that the foam is particularly suitable for large-area application such as skin protection or wound treatment. The high stability means that the product can form a durable protective layer on the skin to prevent ultraviolet rays and pollutant invasion, and meanwhile, the antibacterial and anti-inflammatory properties of zinc oxide are utilized to help reduce inflammation and promote skin self-healing. The stable foam structure of the paint can also lead the smearing process to be even and comfortable, and promote the user experience.

In order to further reduce the foam density and improve the foam stability of the zinc oxide foam product, the inventor thinks from multiple angles that polysaccharides or polymers and the like can be used as foam stabilizers to improve the foam stability, such as optimization of surfactants.

In particular, the inventors have found through extensive experimentation that substitution of dodecyl glucoside for stearyl polyether-21 in the initial formulation does reduce the foam density and increase the foam stability of the zinc oxide foam product.

Specifically, the zinc oxide foam comprises the following raw materials in percentage by mass:

6-8% of isobutane;

4-6% of zinc oxide;

4-6% of 1, 2-butanediol;

4-6% of polydimethylsiloxane;

3-5% of caprylic/capric triglyceride;

3-5% of dodecyl glucoside;

2-4% of cetylstearyl alcohol;

2-4% of glycerol;

1-3% of D-panthenol;

1-3% of sunflower seed oil;

1-3% of propane;

stearyl alcohol polyether-2:1-3%;

0.7-2% of hydroxypropyl methyl cellulose;

0.03-0.08% of p-hydroxyacetophenone;

0.1-0.3% of 1, 2-hexanediol;

0.1-0.3% of 1, 3-propylene glycol;

0.05-0.2% of calendula extract;

0.02-0.06% of phenoxyethanol;

0.02-0.06% of methylparaben;

The balance being water.

In the embodiment, the calendula extract is 10:1/kg in specification and NB9635412 in product number.

In the examples, each raw material was calculated as 100% of the effective matter content unless otherwise specified.

Example 1

7% of isobutane;

zinc oxide (particle size 100 nm): 5%;

5% of 1, 2-butanediol;

5% of polydimethylsiloxane;

Caprylic/capric triglyceride 4%;

Stearyl alcohol polyether-21:4%;

cetostearyl alcohol 3%;

3% of glycerol;

2% of D-panthenol;

2% of sunflower seed oil;

2% of propane;

Stearyl alcohol polyether-2:2%;

1% of hydroxypropyl methyl cellulose;

0.06 percent of p-hydroxyacetophenone;

0.2% of 1, 2-hexanediol;

0.2% of 1, 3-propylene glycol;

0.1% of calendula extract;

0.04% of phenoxyethanol;

0.04% of methylparaben;

The balance being water.

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

dissolving hydroxypropyl methylcellulose in water at room temperature, stirring for 4 hours at 500 rpm, and standing for 24 hours to form hydroxypropyl methylcellulose solution;

Zinc oxide, 1, 2-butanediol, polydimethylsiloxane, caprylic/capric triglyceride, stearyl alcohol polyether-21, cetostearyl alcohol, glycerol, D-panthenol, sunflower seed oil and stearyl alcohol polyether-2 are mixed, and stirred for 20 minutes to be uniform at 60 ℃ at 500 rpm to form a primary mixed solution;

adding 1, 2-hexanediol, 1, 3-propanediol, calendula extract, p-hydroxyacetophenone, phenoxyethanol and methylparaben into the primary mixed solution, and continuing stirring at 60 ℃ for 20 minutes at 500 rpm to obtain a mixture;

Adding the mixture into hydroxypropyl methyl cellulose solution, stirring for 90 minutes at 700 rpm until the mixture is uniform;

homogenizing under high pressure (1500 bar) for 8 min to obtain homogenized emulsion;

and filling the homogenized emulsion and a gas mixture consisting of isobutane and propane into an aerosol tank, and controlling the pressure in the tank to be 0.4MPa to obtain the zinc oxide foam.

Example 2

Example 2 differs from example 1 only in that zinc oxide having a particle size of 50 nm was used.

Example 3

Example 3 differs from example 1 only in that zinc oxide having a particle size of 300 nm was used.

Example 4

Example 4 differs from example 1 only in that the particle size of the zinc oxide used is 800 nm.

Example 5

Example 5 differs from example 1 only in that "steareth-21:4%" is replaced by "dodecyl glucoside 4%".

Example 6

Example 6 differs from example 1 only in that "stearyl polyether-21:4% and stearyl polyether-2:2%" are replaced by "dodecyl glucoside: 6%".

Example 7

Example 7 differs from example 1 only in that "steareth-21:4% and steareth-2:2%" are replaced by "steareth-2:6%".

Comparative example 1

A cosmetic foam comprises the following raw materials in percentage by mass:

7% of isobutane;

5% of 1, 2-butanediol;

5% of polydimethylsiloxane;

Caprylic/capric triglyceride 4%;

Stearyl alcohol polyether-21:4%;

cetostearyl alcohol 3%;

3% of glycerol;

2% of D-panthenol;

2% of sunflower seed oil;

2% of propane;

Stearyl alcohol polyether-2:2%;

1% of hydroxypropyl methyl cellulose;

0.06 percent of p-hydroxyacetophenone;

0.2% of 1, 2-hexanediol;

0.2% of 1, 3-propylene glycol;

0.1% of calendula extract;

0.04% of phenoxyethanol;

0.04% of methylparaben;

The balance being water.

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

Mixing 1, 2-butanediol, polydimethylsiloxane, caprylic/capric triglyceride, stearyl alcohol polyether-21, cetostearyl alcohol, glycerol, D-panthenol, sunflower seed oil and stearyl alcohol polyether-2, and stirring at 60 ℃ for 500 r/min for 20 min until the mixture is uniform to form a primary mixed solution;

the homogenized emulsion is filled into an aerosol tank together with a gas mixture composed of isobutane and propane, and the pressure in the tank is controlled to be 0.4MPa.

Test example 1 test of foam Density and stability

A transparent cylindrical glass having an inner diameter of 50mm and a height of 100mm was prepared, and the mass A ₁ (g) of the empty glass was weighed.

The aerosol canister was gently shaken at an ambient temperature of 25 ℃ to press the zinc oxide foam into the glass, filling the entire glass, and preventing as much as possible the generation of air bubbles during filling.

The filled glass was allowed to stand for 10 seconds, allowing the foam to expand sufficiently. After that, the foam at the top of the glass was cleaned. Weigh the mass A ₂ (g) of the foam-filled glass.

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

Foam density ρ= (a ₂- A₁)/196.35 g/cm3

The rest was continued for 10 minutes at ambient temperature 25 ℃, at which point the foam height Y (in mm) in the glass was observed and measured.

The foam stabilization rate X is calculated as x=y/100×100%.

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

TABLE 1 stability test results

	Foam stabilization 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

In the present invention, foam density and foam stability are two independent but very important properties. They all have a significant impact on the performance and use experience of the product, but have no direct causal relationship. Foam stability determines how long the foam can last after generation and whether it is prone to rupture when subjected to external forces. The foam density is mainly affected by the nature and proportion of the liquid components in the formulation, the manner in which the foam is produced, and other factors. It affects the feel and coverage of the foam, as well as the effectiveness of the product.

The zinc oxide foam product of the present invention has a low foam density (< 0.12g/cm 3). This lower foam density is of great importance for the performance and use experience of the product:

(1) The product experience is optimized, namely, the product has lighter and more fluffy texture due to lower foam density, can be easily smeared during use, and brings better use experience for users.

(2) The improved coverage, lower foam density, also means that the foam can cover a larger area with the same mass, which is very advantageous for applications requiring a large area of use, such as in skin protection, wound treatment, etc.

The zinc oxide foam product of the present invention has excellent foam stability. Means that:

(1) Long lasting protection-the stability of the zinc oxide foam is high, meaning that it does not dissipate or break rapidly after application to the skin. This stability ensures that it stays on the skin surface for a long period of time, forming a stable protective layer. This is important to protect the skin from uv light, contaminants or other factors that may cause skin diseases. In addition, since zinc oxide itself has good antibacterial and anti-inflammatory properties, this stable foam layer can also help reduce the risk of skin inflammation, promoting the natural healing process of the skin.

(2) The use experience is improved, and a zinc oxide foam product with high stability can feel more comfortable when in use. Because the foam has good stability, it does not immediately break or dissipate upon application to the skin, which makes the product easier to apply and can be applied uniformly to the desired area. In addition, the foam is lighter in texture than conventional liquid products, and it feels softer and more comfortable on the skin. This sensation may enhance the user's use experience, making them more willing to use the product regularly to protect their skin.

Further, comparing the difference between comparative example 1 and example 1, we can find that the only difference is the presence of zinc oxide. Through the foam stability test, we observed that when we added a certain amount (4-6%) of zinc oxide, the foam stability was significantly reduced. Zinc oxide is present as a particulate solid, the presence of which may interfere with the stability of the foam. More specifically, these solid particles may cause damage to the foam film, thereby making the foam more prone to rupture.

In addition, the addition of zinc oxide may also affect the surfactant in the foam, which affects the arrangement and stability of the surfactant on the surface of the liquid film, further reducing the stability of the foam. Thus, based on experimental results and these possible mechanisms, we can conclude that the addition of zinc oxide results in a decrease in foam stability.

Further, after zinc oxide is added to the formulation, when the particle size of zinc oxide is in the range of 100-300 nm, the particles may be better distributed in the liquid film with less damage to the liquid film. Small particles (e.g., 50 nanometers) may aggregate more easily, resulting in a localized decrease in liquid film stability, while larger particles (e.g., 800 nanometers) may affect the integrity of the liquid film and thus the stability of the foam due to their oversized. The change in particle size of zinc oxide may affect its interaction with the surfactant. At smaller (e.g., 50 nm) or larger (e.g., 800 nm) particle sizes, zinc oxide may adsorb the surfactant more strongly, thereby altering the alignment of the surfactant on the surface of the liquid film, further affecting foam stability. The particle size of zinc oxide may also affect its distribution in the foam. Ideally, it is desirable that zinc oxide be uniformly distributed throughout the foam, smaller (e.g., 50 nm) particles may be maldistributed due to agglomeration, while larger (e.g., 800 nm) particles may be oversized to affect their distribution in the foam. Thus, considering the above factors in combination, we can conclude that the effect of zinc oxide may be relatively small in the particle size range of 100-300 nanometers, resulting in a foam with better stability. The data comparison of the test cases also effectively verifies the above.

For example 5, the stearyl polyether-2 and the lauryl glucoside may form a specific complementary structure in the liquid, which structure allows them to jointly reduce the surface tension of the liquid, thus increasing the stability of the foam. In addition, this combination of steareth-2 and dodecyl glucoside may also improve the density of the foam. When a surfactant forms a foam in a liquid, the density of the foam is primarily dependent on the mass of the liquid and the volume of the foam. If the combination of two surfactants is capable of forming a larger volume of foam, the density of the foam will be correspondingly reduced at the same mass of liquid. Overall, the stearyl polyether-2 and the lauryl glucoside may have a synergistic effect to some extent, which together increase the stability of the foam and reduce the foam density. However, this is merely a theoretical explanation, and the exact mechanism may require further experimental verification.

Test example 2:

conventional data testing was performed on example 1:

Table 2 conventional test results for zinc oxide foam

Inspection item	Index (I)	Measured data
			Colony count CFU/g	≤1000 CFU/g	300 CFU/g
Total number of moulds and yeasts CFU/g	<100 CFU/g	20 CFU/g
			Heat-resistant coliform group/g	Cannot be detected	0
Staphylococcus aureus/g	Cannot be detected	0
			Pseudomonas aeruginosa/g	Cannot 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. The zinc oxide foam comprises the following raw materials in percentage by mass:

6-8% of isobutane;

4-6% of zinc oxide;

4-6% of 1, 2-butanediol;

4-6% of polydimethylsiloxane;

3-5% of caprylic/capric triglyceride;

3-5% of dodecyl glucoside;

2-4% of cetylstearyl alcohol;

2-4% of glycerol;

1-3% of D-panthenol;

1-3% of sunflower seed oil;

1-3% of propane;

stearyl alcohol polyether-2:1-3%;

0.7-2% of hydroxypropyl methyl cellulose;

0.03-0.08% of p-hydroxyacetophenone;

0.1-0.3% of 1, 2-hexanediol;

0.1-0.3% of 1, 3-propylene glycol;

0.05-0.2% of calendula extract;

0.02-0.06% of phenoxyethanol;

0.02-0.06% of methylparaben;

the balance being water;

wherein the particle size of the zinc oxide is in the range of 100-300 nanometers.