Emulsifier as well as preparation method and application thereof

Abstract

The invention discloses an emulsifier as well as a preparation method and application thereof. The emulsifier is prepared from the following components in percentage by mass: 40 to 70 percent of polyglycerol-6 polyricinoleate, 20 to 40 percent of polyglycerol-2 isostearate and 10 to 20 percent of dispersing agent. The emulsifier provided by the invention has the advantages of strong emulsifying capacity, small dosage and capability of emulsifying a macromolecular chemical sun-screening agent, and solves the problem that a water-in-oil sun-screening product containing the macromolecular chemical sun-screening agent is unstable, so that the stability of the sun-screening product is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cosmetics, and in particular to an emulsifier and a preparation method and application thereof. Background Art

[0002] Sunscreens can be divided into physical sunscreens and chemical sunscreens according to their sun protection mechanism. Physical sunscreens mainly reduce the damage to the skin by reflecting or scattering ultraviolet rays. They are usually thick and sticky, which increases the difficulty of subsequent makeup application and is not skin-friendly overall. Chemical sunscreens achieve the purpose of sun protection by absorbing the part of ultraviolet rays that damage the skin. Their advantages are that they are relatively light and have a good skin feel, but they usually require multiple sunscreens to be used in combination, which can easily irritate the skin. In fact, since the first sunscreen product containing chemical sunscreens was launched in 1928, chemical sunscreens have been constantly iterating their ingredients and technologies in the past hundred years. Commonly used small molecule sunscreens include ethylhexyl methoxycinnamate, dibenzophenone-3, 4-methylbenzylidene camphor, octocrylene, and other small molecule sunscreens.

[0003] Even with their development to this day, small molecule sunscreens still have safety concerns. According to a study published in 2019 by the U.S. Food and Drug Administration's Center for Drug Evaluation and Research, seven chemicals commonly found in sunscreens are absorbed into the human blood circulation at levels exceeding the safety threshold after only a single application. The researchers in the report further stated that being absorbed into the body through the skin does not mean that these specific ingredients are unsafe, or that the sunscreen is unsafe. However, another study in 2010 found the common UVB sunscreen octyl methoxycinnamate in breast milk. Therefore, an important direction in existing research on sunscreens is to minimize the probability of sunscreens penetrating into the human body through the skin.

[0004] As mentioned above, since physical sunscreens do not feel as good as chemical sunscreens on the skin, chemical sunscreens are still the mainstream in the market. However, traditional small molecule chemical sunscreens are easily absorbed into the human body through the skin, which is a hidden danger. According to the "Technical Guidelines for Cosmetic Safety Assessment" issued by the State Food and Drug Administration, the molecular structure and properties of raw materials are related to transdermal absorption rate. For raw materials with a molecular weight > 500Da, their transdermal absorption rate is significantly reduced (Table 1 below shows the relationship between the molecular weight and toxicity of common sunscreens). Therefore, in recent years, by selecting large molecular chemical sunscreens with a molecular weight greater than 500Da, avoiding or reducing the addition of small molecule chemical sunscreens, the disadvantage of traditional sunscreens that they are easy to penetrate into the blood can be overcome, and the effect of not being easily absorbed through the skin, being safer and more effective can be achieved through large molecules. This type of sunscreen product is becoming more and more popular in the market.

[0005] Table 1

[0006]

[0007] However, due to their large molecular weight, macromolecular chemical sunscreens are difficult to emulsify and stabilize in water-in-oil (W / O) systems. They often have emulsification stability problems such as cracking and oiling at low temperatures, and instability at high temperatures, room temperatures, or centrifugation, which affect the product's feel during use and shelf stability. For this reason, sunscreen products containing macromolecular chemical sunscreens around the world generally use water-in-oil (O / W) systems or shake-bead systems that do not require suspension stability. However, these products all have the inherent disadvantages of water-in-oil systems, such as poor waterproofing, short-lasting sun protection, and insufficient skin moisturizing.

[0008] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0009] In view of the above-mentioned deficiencies in the prior art, the present invention provides an emulsifier and a preparation method and application thereof, so as to solve the problem of instability of existing water-in-oil sunscreen products containing macromolecular chemical sunscreens.

[0010] The technical solution adopted by the present invention to solve the above technical problems is as follows:

[0011] The first aspect of the present invention provides an emulsifier, which comprises, by mass percentage, 40-70% of polyglycerol-6 polyricinoleate, 20-40% of polyglycerol-2 isostearate, and 10-20% of a dispersant.

[0012] Preferably, the emulsifier comprises, by mass percentage, 58% of polyglycerol-6 polyricinoleate, 26% of polyglycerol-2 isostearate, and 16% of dispersant.

[0013] Preferably, the dispersant is selected from one or both of polyhydroxystearic acid and lecithin.

[0014] Preferably, the emulsifier is a water-in-oil emulsifier.

[0015] The second aspect of the present invention provides a method for preparing the above-mentioned emulsifier, the preparation method comprising the following steps:

[0016] The dispersant is subjected to a heat treatment, and then polyglyceryl-6 polyricinoleate and polyglyceryl-2 isostearate are added to the heat-treated dispersant, followed by stirring to obtain the emulsifier.

[0017] Preferably, the step of heating the dispersant comprises: heating the dispersant to 70-80° C. and continuously stirring until the dispersant is completely dissolved.

[0018] The third aspect of the present invention provides use of the above-mentioned emulsifier in sunscreen products.

[0019] Preferably, the sunscreen product contains a macromolecular chemical sunscreen agent, and the molecular weight of the macromolecular chemical sunscreen agent is greater than 500Da.

[0020] A fourth aspect of the present invention provides a sunscreen product, comprising the above-mentioned emulsifier.

[0021] Preferably, the sunscreen product further comprises a macromolecular chemical sunscreen agent, and the molecular weight of the macromolecular chemical sunscreen agent is greater than 500 Da.

[0022] Beneficial effects:

[0023] The invention discloses an emulsifier and a preparation method and application thereof. The emulsifier provided by the invention has the advantages of strong emulsification ability, small dosage and the ability to emulsify macromolecular chemical sunscreens, solves the problem of instability of water-in-oil sunscreen products containing macromolecular chemical sunscreens, increases the amount of macromolecular chemical sunscreens added in water-in-oil sunscreen products, reduces the amount of small molecule chemical sunscreens added, thereby reducing the risk of small molecule chemical sunscreens easily penetrating into blood, thereby improving the safety of sunscreen products; and, since the water-in-oil system has better water resistance than the oil-in-water system, after solving the stability of the macromolecular chemical sunscreen in the water-in-oil system, the water resistance of the product containing the macromolecular sunscreen can be improved. DETAILED DESCRIPTION

[0024] The present invention provides an emulsifier and a preparation method and application thereof. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] Sunscreens can be divided into physical sunscreens and chemical sunscreens according to the sunscreen mechanism. Currently, the commonly used chemical sunscreens are small molecule chemical sunscreens, most of which are below 500 Daltons, which can easily penetrate into the skin and even the blood. For this reason, macromolecular chemical sunscreens with a molecular weight greater than 500 Daltons have gradually attracted everyone's attention. However, due to their large molecular weight, macromolecular chemical sunscreens often have emulsification problems such as cracking and oiling at low temperatures, high temperature, room temperature or centrifugal instability in oil-in-water systems. For this reason, sunscreen products containing macromolecular chemical sunscreens around the world are generally solved by adopting a water-in-oil system or a shaking bead system that does not require suspension stability. However, such products all have the inherent disadvantages of the water-in-oil system, such as non-waterproofness and non-durable sunscreen.

[0026] Based on this, an embodiment of the present invention provides an emulsifier, which includes, by mass percentage, 40-70% of polyglycerol-6 polyricinoleate, 20-40% of polyglycerol-2 isostearate, and 10-20% of a dispersant.

[0027] Polyglyceryl-6 polyricinoleate is a macromolecular polyglycerol emulsifier with an HLB value of 3.3 (HLB value is an important indicator of surfactants, which represents the size and balance of power between the hydrophilic group and the lipophilic group in the surfactant molecule. The size of the HLB value directly reflects the hydrophilicity or lipophilicity of the surfactant: the larger the HLB value, the stronger the hydrophilicity of the surfactant; conversely, the smaller the HLB value, the stronger its lipophilicity), and polyglyceryl-2 isostearate is a small molecule polyglycerol emulsifier with an HLB value of 4.7. Polyglyceryl-6 polyricinoleate and polyglyceryl-2 isostearate have high hydrophilicity, and their HLB does not change with temperature, so they have better stability; polyglyceryl-6 polyricinoleate and polyglyceryl-2 isostearate have high cloud points, and are less affected by the stability caused by temperature and HLB; and polyglyceryl-6 polyricinoleate and polyglyceryl-2 isostearate easily form α gel, which has the characteristics of high moisturizing, good ductility and non-stickiness.

[0028] In contrast, other silicone oil emulsifiers such as cetyl PEG / PPG-10 / 1 polydimethicone, lauryl PEG-9 polydimethylsiloxyethyl polydimethicone, sorbitan isostearate, and polyglyceryl-4 isostearate are prone to stability problems in formulas containing large molecular chemical sunscreens due to their poor W / O hydrophilicity and HLB changes with temperature. After the emulsifier has been allowed to stand for 24 hours, stability problems such as cracking and oil release, centrifugal oil release, and freezing cracking and oil release will generally occur.

[0029] In addition, the embodiment of the present invention also adds a dispersant to the emulsifier, which can prevent polyglycerol-6 polyricinoleate and polyglycerol-2 isostearate from combining with each other, so that the particles in the emulsifier are more evenly dispersed, giving the emulsifier a better emulsifying function, and at the same time, it is easier to form an alpha gel, and has a stronger water retention capacity. If polyglycerol-6 polyricinoleate and polyglycerol-2 isostearate are compounded without a dispersant, stability problems will also occur in the formula containing macromolecular chemical sunscreens after emulsification.

[0030] In some embodiments, the emulsifier comprises, by weight percentage, 58% polyglyceryl-6 polyricinoleate, 26% polyglyceryl-2 isostearate, and 16% dispersant.

[0031] When the emulsifier includes 58% of polyglycerol-6 polyricinoleate, 26% of polyglycerol-2 isostearate and 16% of polyhydroxystearic acid by mass percentage, the effect of emulsifying the macromolecular chemical sunscreen is the best. The emulsified macromolecular chemical sunscreen does not produce oil after centrifugation at 3000 rpm for 30 minutes, and there is no abnormality in the cold and hot stability test for 3 months.

[0032] In some embodiments, the dispersant is selected from one or more of polyhydroxystearic acid and lecithin.

[0033] Since inorganic sunscreens will absorb some of the solvents originally used to dissolve macromolecular chemical sunscreens, the macromolecular sunscreens will not be fully dissolved. The addition of dispersants can reduce the adsorption of inorganic sunscreens on solvents, improve the solubility of macromolecular chemical sunscreens, and thus enhance the emulsification effect of emulsifiers on macromolecular sunscreens.

[0034] Specifically, the dispersant can be attached to the surface of the inorganic sunscreen particles, thereby preventing them from combining with each other through three-dimensional structure and electrostatic repulsion, making the particle size more uniform and fine, and giving the sunscreen product better emulsification function. If the dispersant such as polyhydroxystearic acid provided in the embodiment of the present invention is combined with other emulsifiers, in a formula containing macromolecular chemical sunscreens, stability problems will also occur after emulsification.

[0035] In some embodiments, the emulsifier is a water-in-oil emulsifier.

[0036] The present invention provides a method for preparing the emulsifier, which comprises the following steps:

[0037] The dispersant is subjected to a heat treatment, and then polyglyceryl-6 polyricinoleate and polyglyceryl-2 isostearate are added to the heat-treated dispersant, and stirred to obtain a transparent liquid, which is the emulsifier.

[0038] Generally, the dispersant is semisolid at room temperature and dissolves after heating, while polyglyceryl-6 polyricinoleate and polyglyceryl-2 isostearate are liquids at room temperature. After the three substances are mixed, they return to room temperature and become transparent liquids to obtain the emulsifier.

[0039] In some embodiments, the step of heating the dispersant is specifically: heating the dispersant to 70-80° C. and continuously stirring until the dispersant is completely dissolved.

[0040] The embodiment of the present invention provides the use of the above-mentioned emulsifier in sunscreen products.

[0041] In some embodiments, the sunscreen product contains a macromolecular chemical sunscreen agent having a molecular weight greater than 500 Da.

[0042] The embodiment of the present invention provides a sunscreen product, which includes the above-mentioned emulsifier. The sunscreen product can be a sunscreen lotion, a sunscreen cream, etc.

[0043] In some embodiments, the sunscreen product further comprises a macromolecular chemical sunscreen agent having a molecular weight greater than 500 Da.

[0044] In the sunscreen W / O (water-in-oil) product system, the sunscreen is generally oil-soluble, which serves as the external phase, also known as the continuous phase. The aqueous phase is the internal phase, also known as the dispersed phase. Commonly used small-molecule chemical sunscreens are liquids, and macromolecule chemical sunscreens are solids. Macromolecule chemical sunscreens need to be dissolved with small-molecule chemical sunscreens or other oils. The stability problems of the O / W system containing macromolecule chemical sunscreens are mainly the crystallization of macromolecule chemical sunscreens, the unstable aggregation of emulsions, and the aggregation of sunscreen powders (such as zinc oxide and titanium dioxide). Therefore, this requires that the water-in-oil emulsifier for emulsifying macromolecule chemical sunscreens has excellent emulsification ability to form finer emulsions, and also has good powder dispersion ability to avoid the aggregation of sunscreen powders.

[0045] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, and are only for illustrating the present invention but not limiting the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0046] Example 1

[0047] A preparation method of a water-in-oil sunscreen lotion comprises the following steps:

[0048] Heat phase A to 80°C, stir and dissolve evenly, add phase B to phase A, and homogenize at high speed for 7 minutes to obtain phase A+B, heat phase C to 80°C, and stir and dissolve evenly; slowly add phase C to phase A+B while stirring, and homogenize at high speed for 3 minutes, then slowly cool to 45°C to obtain phase A+B+C, add phase D to phase A+B+C, and homogenize at high speed for 1 minute to obtain water-in-oil sunscreen lotion.

[0049] Phase A includes 2.20 parts by mass of polyglyceryl-6 polyricinoleate, 1.00 parts by mass of polyglyceryl-2 isostearate, 0.60 parts by mass of polyhydroxystearic acid, 5.00 parts by mass of neopentyl glycol diheptanoate, 4.00 parts by mass of ethylhexyl salicylate, 8.50 parts by mass of ethylhexyl methoxycinnamate, 2.00 parts by mass of bis-ethylhexyloxyphenol methoxyphenyl trisaccharide, 2.00 parts by mass of octocrylene, 3.00 parts by mass of diethylamino hydroxybenzoyl hexyl benzoate and 1.00 parts by mass of distear dimethyl ammonium hectorite, phase B includes 5.00 parts by mass of isododecane and 2.00 parts by mass of zinc oxide, phase C includes 0.05 parts by mass of EDTA-2Na, 1.70 parts by mass of sodium chloride, 5.00 parts by mass of butylene glycol, 8.00 parts by mass of glycerol and 0.80 parts by mass, and phase D includes 0.80 parts by mass of a preservative.

[0050] Example 2

[0051] A preparation method of a water-in-oil sunscreen lotion. The method of this embodiment is basically the same as that of Example 1, except that the amount of polyglycerol-6 polyricinoleate in phase A is 2.00 parts by mass, and the amount of polyhydroxystearic acid is 0.40 parts by mass.

[0052] Comparative Example 1

[0053] A sunscreen lotion is prepared. The method of this comparative example is basically the same as that of Example 1, except that: polyhydroxystearic acid is not added to phase A, and 0.60 parts by weight of PEG-10 polydimethylsilane is added.

[0054] Comparative Example 2

[0055] A sunscreen lotion is prepared. The method of this comparative example is basically the same as that of Example 1, except that: polyhydroxystearic acid is not added to phase A, and 0.60 parts by mass of polyglycerol-10 polyhydroxystearate is added.

[0056] Comparative Example 3

[0057] A sunscreen lotion is prepared. The method of this comparative example is basically the same as that of Example 1, except that the amount of polyglycerol-6 polyricinoleate in phase A is 1.00 parts by mass, the amount of polyglycerol-2 isostearate is 2.00 parts by mass, and no polyhydroxystearic acid is added.

[0058] Comparative Example 4

[0059] A sunscreen lotion is prepared by the method of this comparative example being substantially the same as that of Example 1, except that the amount of polyglycerol-6 polyricinoleate in phase A is 1.00 parts by mass, and the amount of polyglycerol-2 isostearate is 2.00 parts by mass.

[0060] Comparative Example 5

[0061] A sunscreen lotion is prepared. The method of this comparative example is basically the same as that of Example 1, except that: the amount of polyglyceryl-6 polyricinoleate in phase A is 2.50 parts by mass, polyglyceryl-2 isostearate and polyhydroxystearic acid are not added, and 2.50 parts by mass of cetyl PEG / PPG-10 / 1 polydimethylsiloxane and 0.80 parts by mass of magnesium stearate are added.

[0062] Comparative Example 6

[0063] A method for preparing a sunscreen lotion is basically the same as that of Example 1, except that: in phase A, no polyglyceryl-6 polyricinoleate, polyglyceryl-2 isostearate and polyhydroxystearic acid are added, and 1.50 parts by mass of cetyl PEG / PPG-10 / 1 polydimethylsiloxane, 1.50 parts by mass of PEG-10 polydimethylsilane and 3.00 parts by mass of lauryl PEG-9 polydimethylsiloxyethyl polydimethylsiloxane are added.

[0064] Comparative Example 7

[0065] A sunscreen lotion is prepared. The comparative method is basically the same as that in Example 1, except that: polyglyceryl-6 polyricinoleate, polyglyceryl-2 isostearate and polyhydroxystearic acid are not added to phase A, and 3.00 parts by mass of lauryl PEG-9 polydimethylsiloxyethyl polydimethylsiloxane is added.

[0066] The raw material compositions and dosages of Examples 1-2 and Comparative Examples 1-7 are shown in Table 2 below:

[0067] Table 2

[0068]

[0069] The sunscreen lotions prepared in Examples 1-2 and Comparative Examples 1-7 were subjected to stability tests, and the test scheme was as follows:

[0070] The prepared sunscreen samples were packaged into 15 mL glass bottles and labeled.

[0071] Test environment: heat resistance (45℃) for three months, cold resistance (-10℃) for three months, hot and cold alternating cycle (-15℃-25℃) for one month, and room temperature shelf for three months. The test results are shown in Table 3 below.

[0072] Table 3

[0073]

[0074] The above table shows that the sunscreen lotion prepared in Example 1-2 performed normally without oil secretion in the experiments of heat resistance (45°C) for three months, cold resistance (-10°C) for three months, alternating hot and cold cycles (-15°C-25°C) for one month, shelf storage at room temperature for three months, and centrifugation at 2500r / min the next day.

[0075] The sunscreen lotion prepared in Comparative Example 1 performed normally in the experiments of heat resistance (45°C) for three months, hot and cold alternating cycle (-15°C-25°C) for one month, and shelf at room temperature for three months. However, under the cold resistance (-10°C) test condition, oil leakage occurred in 7 days, and slight oil leakage occurred in the experiment of centrifugation at 2500r / min the next day.

[0076] The sunscreen lotion prepared in Comparative Example 2 performed normally in the experiments of heat resistance (45°C) for three months, hot and cold alternating cycle (-15°C-25°C) for one month, and shelf at room temperature for three months. However, under the cold resistance (-10°C) test condition, oil leakage occurred in 7 days, and slight oil leakage occurred in the experiment of centrifugation at 2500r / min the next day.

[0077] The sunscreen lotion prepared in Comparative Example 3 performed normally in the experiments of heat resistance (45°C) for three months, hot and cold alternating cycle (-15°C-25°C) for one month, shelf at room temperature for three months, and centrifugation at 2500r / min the next day. However, under the cold resistance (-10°C) test condition, oil leakage occurred in 7 days.

[0078] The sunscreen lotion prepared in Comparative Example 4 performed normally in the experiments of cold and hot alternating cycles (-15℃-25℃) for one month, shelf storage at room temperature for three months, and centrifugation at 2500r / min the next day. However, under the cold resistance (-10℃) test condition, oil leakage occurred in 7 days, and under the heat resistance (45℃) test condition, oil leakage occurred in 84 days.

[0079] The sunscreen lotion prepared in Comparative Example 5 performed normally in a one-month experiment of alternating cold and hot cycles (-15°C-25°C). However, under the cold-resistant (-10°C) test condition, oil leakage occurred in 7 days, under the heat-resistant (45°C) test condition, oil leakage occurred in 56 days, under the normal temperature shelf test condition for three months, oil leakage occurred in 28 days, and under the centrifugal test condition of 2500r / min the next day, slight oil leakage occurred.

[0080] The sunscreen lotion prepared in Comparative Example 6 produced oil in 3 days under the test conditions of alternating hot and cold cycles (-15℃-25℃), produced oil in 3 days under the cold-resistant test conditions (-10℃), produced oil in 1 day under the heat-resistant test conditions (45℃), produced oil on the next day under the test conditions of three months on the room temperature shelf, and produced oil on the next day under the test conditions of centrifugation at 2500r / min.

[0081] The sunscreen lotion prepared in Comparative Example 7 showed oil secretion in 3 days under the test conditions of alternating hot and cold cycles (-15℃-25℃), showed oil secretion in 7 days under the cold-resistant test conditions (-10℃), showed oil secretion in 3 days under the heat-resistant test conditions (45℃), showed oil secretion in 7 days under the test conditions of three months on the normal temperature shelf, and showed oil secretion under the test conditions of centrifugation at 2500r / min the next day.

[0082] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. An emulsifier, characterized in that The emulsifier comprises, by mass percentage, 40-70% of polyglycerol-6 polyricinoleate, 20-40% of polyglycerol-2 isostearate and 10-20% of a dispersant.

2. The emulsifier according to claim 1, characterized in that The emulsifier comprises, by mass percentage, 58% of polyglycerol-6 polyricinoleate, 26% of polyglycerol-2 isostearate, and 16% of a dispersant.

3. The emulsifier according to claim 1, characterized in that The dispersant is selected from one or both of polyhydroxystearic acid and lecithin.

4. The emulsifier according to claim 1, characterized in that The emulsifier is a water-in-oil emulsifier.

5. A method for preparing the emulsifier according to claim 1, characterized in that: The preparation method comprises the following steps: The dispersant is subjected to a heat treatment, and then polyglyceryl-6 polyricinoleate and polyglyceryl-2 isostearate are added to the heat-treated dispersant, followed by stirring to obtain the emulsifier.

6. The method for preparing an emulsifier according to claim 5, characterized in that: The step of heating the dispersant is specifically: heating the dispersant to 70-80° C. and continuously stirring until the dispersant is completely dissolved.

7. Use of the emulsifier according to any one of claims 1 to 4 in sunscreen products.

8. The use according to claim 7, characterized in that: The sunscreen product contains a macromolecular chemical sunscreen agent, and the molecular weight of the macromolecular chemical sunscreen agent is greater than 500Da.

9. A sunscreen product, characterized in that: The sunscreen product comprises the emulsifier according to claims 1-4.

10. The sunscreen product according to claim 9, characterized in that: The sunscreen product also includes a macromolecular chemical sunscreen agent, and the molecular weight of the macromolecular chemical sunscreen agent is greater than 500Da.

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