CN111000733B

CN111000733B - Liquid crystal emulsion

Info

Publication number: CN111000733B
Application number: CN202010004903.2A
Authority: CN
Inventors: 彭金山; 唐新宜; 朱俊华
Original assignee: Guangzhou Jinshang Cosmetics Co ltd
Current assignee: Guangzhou Jinshang Cosmetics Co ltd
Priority date: 2020-01-03
Filing date: 2020-01-03
Publication date: 2022-09-02
Anticipated expiration: 2040-01-03
Also published as: CN111000733A

Abstract

The invention discloses a liquid crystal emulsion which is mainly prepared from the following raw materials in percentage by mass: 1-3% of a main emulsifier, 0.5-2.0% of a secondary emulsifier, 0.5-3.0% of a co-emulsifier, 0.05-0.40% of a main thickener, 0-5% of other conventional additives, 5-12% of a humectant, 10-20% of an emollient and the balance of deionized water. The liquid crystal emulsion improves the components of the emulsifier and the thickener, and the prepared emulsion has high liquid crystal content and is relatively stable.

Description

Liquid crystal emulsion

Technical Field

The invention belongs to the technical field of skin care products, and particularly relates to a liquid crystal emulsion.

Background

Along with the improvement of living standard of people, consumers put forward higher requirements on skin care and maintenance, the moisture content in the skin is the guarantee of guaranteeing the health of the skin, and the phenomena of aging, chapping and the like of the skin can be prevented. The moisture retention of skin care products is the focus and focus of developing such products. Generally, the moisturizing emulsion has a function of a moisturizing barrier such as grease and a humectant. After spreading, a layer of hydrophobic barrier can be formed on the surface of the skin, and the outward loss of water in the skin can be effectively prevented. The liquid crystal structure is called as the second layer of skin of a human body, the liquid crystal structure is similar to the structure of the horny layer of the skin, so that the liquid crystal structure has better compatibility with the skin, and the liquid crystal layer contains about 13-19% of bound water. Researches find that the lamellar liquid crystal structure has the characteristics of better slow release property, stability, moisture retention, barrier effect and the like, the emulsion with the liquid crystal structure is easier to spread on the surface of the skin, and the liquid crystal layer is easy to relatively slide and can be perfectly attached to the skin.

Compared with the common emulsion, the emulsion containing the liquid crystal structure has better moisturizing effect on the skin, moisturizing components in the emulsion are easily absorbed by the skin, the effect on the skin is more obvious, and the effect of long-acting moisturizing is finally achieved.

At present, there are many reports and patents related to the preparation of liquid crystal emulsion, but there are few reports on the formula optimization of liquid crystal content, and particularly, there is no report on the research on the liquid crystal stability of the system with electrolyte.

The liquid crystal emulsion is a relatively complex system, comprises several even more than ten components, and the emulsion with good stability, more liquid crystals and good moisturizing effect cannot be prepared by simply selecting one liquid crystal emulsifier. The amount of liquid crystal in the liquid crystal emulsion is related to the type of the emulsifier, the proportion of the emulsifier, the type of the grease, the thickener, the electrolyte and the like. Therefore, good liquid crystal emulsions can only be obtained by screening and optimization through a large number of orthogonal experiments.

In order to solve the above problems, the present invention proposes a liquid crystal emulsion.

Disclosure of Invention

The invention aims to provide a liquid crystal emulsion, which mainly solves the technical problems that the emulsion in the prior art has poor stability and moisturizing effect, and the liquid crystal structure is unstable in the presence of electrolyte (generally referred to as monovalent salt).

The above object of the present invention can be achieved by the following technical solutions: a liquid crystal emulsion is mainly prepared from the following raw materials in percentage by mass: 1-3% of a main emulsifier, 0.5-2.0% of a secondary emulsifier, 0.5-3.0% of a co-emulsifier, 0.05-0.40% of a main thickener, 0-5% of other conventional additives, 5-12% of a humectant, 10-20% of an emollient and the balance of deionized water.

In the absence of electrolytes in other conventional adjuvants, the amount of liquid crystals in the liquid crystal emulsion can be increased and the stability of the liquid crystal emulsion can be maintained by introducing a suitable secondary emulsifier into the formulation. Meanwhile, a single main thickener can enable enough liquid crystal quantity to exist in the liquid crystal emulsion, and enable the emulsion to obtain ideal viscosity and good stability, but because other conventional auxiliaries can bring electrolytes, the existence of the electrolytes can cause the problems that the quantity of the liquid crystals in the liquid crystal emulsion is reduced along with the change of time, the viscosity and the stability of the liquid crystal emulsion are reduced, and the like, so that the problem that the stability of the liquid crystals in the liquid crystal emulsion and the stability of the emulsion are reduced due to the existence of the electrolytes is solved, and the problem of the liquid crystal emulsion is solved.

Therefore, as an improvement of the present invention:

the invention provides a liquid crystal emulsion which is mainly prepared from the following raw materials in percentage by mass: 1-3% of a main emulsifier, 0.5-2.0% of a secondary emulsifier, 0.5-3.0% of a co-emulsifier, 0.05-0.20% of a main thickener, 0.05-0.20% of a secondary thickener, 0.05-5% of other conventional additives, 5-12% of a humectant, 10-20% of an emollient and the balance of deionized water, wherein the other conventional additives contain electrolyte.

In the raw materials of the liquid crystal emulsion:

preferably, in the present invention the primary emulsifier is an alkyl glycoside, which is sold under the trade name MONTANOV 68 and is chemically named cetearyl alcohol (and) cetearyl glucoside, or which is sold under the trade name MONTANOV82 and is chemically named cetearyl alcohol (and) cocoyl glucoside.

In the specific embodiment of the invention, screening experiments on several alkyl glycosides with trade names of MONTANOV 68 (M68), MONTANOV82 (M82) and MONTANOV 202 (peanut alcohol and behenyl alcohol glucoside (and) arachidyl glucoside, M202) show that the emulsifying effect is better and the emulsion stability is better when the model M82 or M68 is used as the main emulsifier.

Preferably, the secondary emulsifier is a mixture of glyceryl stearate and PEG-100 stearate, and the product is SIMULSOL 165, abbreviated as A165.

In the specific embodiment of the invention, through screening experiments on a plurality of secondary emulsifiers such as A165, potassium hexadecyl phosphate, sodium stearyl glutamate, behenyl trimethyl ammonium chloride, palmitamidopropyl trimethyl ammonium chloride and the like, the liquid crystal emulsion formed by using the A165 in the application as the secondary emulsifier has the highest liquid crystal content.

Preferably, the co-emulsifier is cetostearyl alcohol, which can help stabilize the emulsion and thicken it, but does not have emulsifying capacity itself.

Preferably, the mass part ratio of the main emulsifier to the secondary emulsifier to the co-emulsifier is 1-3: 1-3: 1 to 3.

Preferably, the mass part ratio of the main emulsifier, the secondary emulsifier and the auxiliary emulsifier is 3: 1: 1.

experiments in specific embodiments of the invention prove that when the mass part ratio of the main emulsifier to the secondary emulsifier to the co-emulsifier is 3: 1: 1, the emulsion has more liquid crystal and better emulsion stability.

Preferably, when the liquid crystal emulsion of the present invention does not contain an electrolyte in the formulation, the main thickener of the present invention is carbomer 940.

Preferably, when the formula of the liquid crystal emulsion contains electrolyte, the main thickener is carbomer 940, and the secondary thickener is xanthan gum or carbomer U21.

Further, the mass part ratio of the carbomer 940 to the xanthan gum is 0.2: 0.15, wherein the mass part ratio of the carbomer 940 to the carbomer 21 is 0.15: 0.1.

in the specific embodiment of the invention, the main thickener carbomer 940 is compounded with the secondary thickeners carbomer 21, xanthan gum and SEPIMAX ZEN which have better electrolyte resistance, so that the viscosity and the stability of the emulsion can achieve better effects under the condition that the electrolyte exists in a formula system. After the test, the number of liquid crystals in the emulsion is smaller after the SEPIMAX ZEN secondary thickening agent is introduced into the system, the number of liquid crystals in the emulsion is larger when the secondary thickening agent such as carbome 21 or xanthan gum is introduced into the system, and the stability of the emulsion is better.

Preferably, the other conventional auxiliary agents comprise one or more of preservatives, essences, chelating agents, pH regulators and functional additives.

Preferably, the preservative of the present invention is a mixture of phenoxyethanol, methylparaben, ethylparaben and ethylhexylglycerol, available under the trade name euxyl K350, from Shumei, Germany.

Preferably, the chelating agent is disodium EDTA.

Preferably, the pH regulator is triethanolamine.

Preferably, the functional additive includes, but is not limited to, one or more of commercially available plant extract, hyaluronic acid and its derivatives, ceramide, sodium pyrrolidone carboxylate, and dipotassium glycyrrhizinate.

Other conventional additives, especially functional additives, may be introduced into electrolytes such as sodium hyaluronate, dipotassium glycyrrhizinate and plant extracts, which adversely affect the amount of liquid crystals in the liquid crystal emulsion, the stability of the liquid crystals and the stability of the emulsion, and can be improved by adding the secondary thickener as described above.

Preferably, the humectant is glycerin, or the humectant is a mixture of glycerin and trehalose, or the humectant is a mixture of glycerin and 1, 3-butanediol.

Preferably, the emollient of the present invention is white oil.

The preparation method of the liquid crystal emulsion, which is a preferable method of the invention, comprises the following steps:

(1) heating the main emulsifier, the secondary emulsifier, the auxiliary emulsifier and the emollient to 75-85 ℃, and uniformly stirring to form a uniform oil phase for later use;

(2) mixing and stirring deionized water, a humectant and a main thickener (when the formula contains electrolyte, a secondary thickener is also added) uniformly, heating to 75-85 ℃ to form a uniform water phase for later use;

(3) directly adding the water phase in the step (2) into the oil phase in the step (1), and homogenizing at the rotating speed of 4500-5500 rpm for 3-8 minutes, wherein the temperature is kept at 75-80 ℃;

(4) slowly cooling and stirring after the emulsion is formed, cooling to 45-55 ℃, adding other residual raw materials in sequence, and continuously stirring for 3-8 minutes;

(5) stopping stirring when the temperature is reduced to 35-45 ℃, and finishing processing to obtain liquid crystal emulsion;

in the preparation method, when the chelating agent disodium EDTA is contained in other conventional additives, the chelating agent disodium EDTA is added and heated together with deionized water, a humectant and a main thickener (when the formula contains electrolyte, a secondary thickener is also added) in the step (2), and the other conventional additives without the chelating agent disodium EDTA or the rest of the other conventional additives can be added together with other rest raw materials such as a preservative and essence after being cooled in the step (4).

Compared with the prior art, the invention has the following advantages:

(1) the liquid crystal emulsion of the invention adopts the main emulsifier M68 or M82 and the secondary emulsifier A165 to remarkably improve the liquid crystal content in the liquid crystal emulsion after being compounded, which indicates that the A165 has the generation promoting or synergistic effect on the liquid crystal structure of an M68 or M82 emulsifying system;

(2) the liquid crystal emulsion disclosed by the invention is compounded by adopting a main emulsifier, a secondary emulsifier, an auxiliary emulsifier, a thickening agent, a humectant and an emollient in a proper proportion, so that the quantity of liquid crystals in an emulsion system can be increased;

(3) in the liquid crystal emulsion, under an emulsion system of electrolyte, the liquid crystal amount of the emulsion system can be increased after the primary emulsifier, the secondary emulsifier, the co-emulsifier, the primary thickener, the secondary thickener, the humectant, the emollient and the electrolyte are compounded in a proper proportion;

(4) the number of the liquid crystal structures plays a key role in the stability of the emulsion and the permeation and absorption of moisturizing components, and the main components and the using amount of the main components in the formula are optimized and configured, so that the emulsion has a high-content and stable liquid crystal structure, and can provide a long-acting moisturizing effect under the synergistic effect of the main components such as an emollient;

(5) the liquid crystal structure and the content of the liquid crystal structure not only affect the skin moisturizing effect, but also affect the stability of the emulsion, and the formula of the liquid crystal emulsion can effectively maintain the stability of liquid crystal, prevent the liquid crystal structure from being damaged and ensure the durability of the efficacy of the emulsion.

Drawings

FIG. 1 is a liquid crystal diagram in example 1;

FIG. 2 is a liquid crystal diagram in example 2;

FIG. 3 is a graph comparing the liquid crystal content of the compounded emulsifier of example 2;

FIG. 4 is a liquid crystal diagram in example 3;

FIG. 5 is a liquid crystal diagram in example 4;

FIG. 6 is a liquid crystal diagram in examples 5 and 6;

FIG. 7 is a liquid crystal diagram of the emulsions of examples 5 and 6 after standing for 90 days;

FIG. 8 is a graph showing the variation of the liquid crystal content of the emulsions in examples 5 and 6.

Detailed Description

The present invention will be further described with reference to specific embodiments, but the scope of the present invention as claimed is not limited to the following embodiments, and the raw materials used in the present invention, which are commercially available unless otherwise specified, are recommended to use from the manufacturers listed in the summary of the present invention.

The invention adopts a plurality of testing methods, including stability testing and liquid crystal content testing. The specific test method is described as follows:

centrifuge stability test

The test specimen was placed in a centrifuge at a set rotation speed of 3000 rpm, and the state of the specimen was observed after 30 minutes.

(a) The samples were judged to have good centrifugal stability without significant delamination, and the results were marked as ≈ b.

(b) Samples were slightly stratified and considered to be of general centrifugal stability, and the results were marked as Δ.

(c) The samples were considered to have poor centrifuge stability if significant delamination occurred, and the results were marked x.

High temperature stability test

The test specimen was placed in a constant temperature oven at 40 ℃ and the state of the specimen was observed for three months.

(a) And if no obvious delamination occurs in the sample, the high-temperature stability is considered to be good, and the result is marked by V.

(b) When the sample was delaminated, the high temperature stability was considered to be poor, and the result was marked as X.

Liquid crystal content measurement

Obtaining an image of an emulsion liquid crystal structure by using a polarizing microscope, analyzing pixels in the image by using PHOTOSOP software, and calculating pixels of a liquid crystal part, wherein the liquid crystal content of the emulsion is calculated by the following formula:

wherein L is the liquid crystal content; p _c Pixels which are part of the image of the liquid crystal; p _g A pixel of an image.

In order to reduce human errors in the calculation, all sample image processing and calculation are completed by the same person.

Example 1

This example provides a variety of emulsion samples, mainly for the types of primary emulsifiers contained in the emulsions of the present invention, to examine the effect of different primary emulsifier structures and types on the formation of liquid crystal structures.

The primary emulsifiers used in this example included: arachidyl alcohol/behenyl alcohol/arachidyl alcohol (abbreviated as M202), cetearyl alcohol/cetearyl glucoside (abbreviated as M68), cetearyl alcohol/cocoyl glucoside (abbreviated as M82), cocoyl glucoside/cocoyl alcohol (abbreviated as MS), polyglycerol-3 methylglucose distearate (abbreviated as TC450), polyglycerol-6 stearate/polyglycerol-6 behenate (abbreviated as PBS6), polyglycerol-3 distearate/glycerol stearate citrate (abbreviated as NC), sucrose polystearate and hydrogenated polyisobutene (abbreviated as ESP), glycerol stearate citrate (abbreviated as AC 62P). Different types of main emulsifiers are added into the same basic formula to prepare a sample to be tested. The formulation composition of each sample to be tested is shown in table 1.

Table 1 example 1 formulation and results

The liquid crystal content and the centrifugal stability results of the emulsions prepared with different types and structures of emulsifiers are shown in table 1, and the liquid crystal diagram is shown in fig. 1. The emulsion prepared from the M-series alkyl glycoside in the formulas 1 to 5 has a large amount of liquid crystal, wherein the M202 liquid crystal has the largest amount, but the emulsion has poor centrifugal stability. In addition, the liquid crystal quantity of M68, M82 and MS are basically the same, but the centrifugal stability of the emulsion prepared by MS is poor. Considering the quantity of liquid crystal and the stability of emulsion comprehensively, M202, M68 and M82 are alternative main emulsifiers, and the samples are completely layered after being placed at the high temperature of 40 ℃ for 3 months, so that the high-temperature stability of the system using a single emulsifier is not ideal, and the emulsification system needs to be improved and a secondary emulsifier is introduced.

Example 2

This example mainly aims at the kind of the secondary emulsifier contained in the emulsion of the present invention to examine the influence of different kinds and structures of the secondary emulsifier on the amount of liquid crystal and the stability of the emulsion.

Considering that the emulsion prepared by using M68 and M82 emulsifiers in example 1 has similar characteristics and the high-temperature stability of liquid crystal emulsion obtained by using a single emulsifier is not ideal enough, M68 in this example represents M68 and M82 emulsifiers, and experiments are carried out below by using M68 and M202 as main emulsifiers to verify the effect of adding a secondary emulsifier on the liquid crystal emulsion, wherein the secondary emulsifier comprises: glyceryl stearate/PEG-100 stearate (A165 for short), potassium hexadecyl phosphate (MCK for short), sodium stearyl glutamate (ESG for short), behenyl trimethyl ammonium chloride (BT 85 for short), and palmityl propyl trimethyl ammonium chloride (PATC for short). Different types of secondary emulsifiers are added into the same basic formula to prepare a sample to be tested. The formulation composition and results for each sample tested are shown in table 2, and the liquid crystal diagram is shown in fig. 2.

Table 2 example 2 formulation and results

As can be seen from the results in Table 2, the liquid crystal content of the emulsion increases after formulation 10 is compounded with the A165-time emulsifier using M68 as the primary emulsifier compared to formulation 2. The liquid crystal content of the emulsion is reduced after the formulas 11 to 14 adopt other secondary emulsifiers to be compounded with M68. The formulas 15 to 19 are compared with the formula 1, and the content of the emulsion liquid crystal is reduced after the M202 is used as the main emulsifier and the secondary emulsifier for compounding. This may be related to whether the primary and secondary emulsifiers have similar alkyl carbon chain lengths. The emulsion after the M68 is compounded with an anionic emulsifier (such as MCK and ESG) has better centrifugal and high-temperature stability, and the emulsion after the M202 is compounded with a cationic emulsifier (such as BT85 and PATC) and the anionic emulsifier ESG has better centrifugal and high-temperature stability, but the problem of less liquid crystal quantity exists. In addition, the emulsion prepared by compounding M68 and A165 has better high-temperature stability. In order to further verify the influence of the combination of alkyl glycoside emulsifiers such as M68, M82 and M202 and the like and the A165 emulsifiers on the change of the liquid crystal quantity, M82 and the A165 are specially added for comparison, and the experimental result is shown in FIG. 3. The results show that the number of the emulsion liquid crystals is increased after M68, M82 and A165 are compounded, wherein the increase range of the number of the emulsion liquid crystals is larger after M68 and A165 are compounded. Therefore, the A165 secondary emulsifier is preferably used in combination with the M68 or M82 primary emulsifier.

Example 3

Generally, the problem of poor emulsion stability can be solved by adding a single main thickener to the emulsion system, and this example mainly aims at the kind of thickener included in the emulsion of the present invention to examine the influence of different kinds and structures of thickeners on the amount of liquid crystal and the emulsion stability. The procedure for screening the thickeners in this example was a one-factor experiment, and the following experiment was conducted with the main emulsifier represented by M68.

The primary emulsifier used in this example was M68, the secondary emulsifier was a165, and the thickener included: xanthan gum, carbomer 940, carbomer 21, hydroxyethyl cellulose (HEC for short), polyacrylamide/C13-14 isoparaffin/lauryl ether-7 (305 for short), sodium acrylate/sodium acryloyldimethyl taurate copolymer/isohexadecane/polysorbate-80 (EG for short), polyacrylate cross-linked polymer-6 (ZEN for short), acrylamide dimethyl taurate/VP copolymer (AVC for short). The samples to be tested were prepared by adding different types of thickeners to the same base formula. The formulation composition and results for each sample tested are shown in table 3, and the lc diagram is shown in fig. 4.

Table 3 example 3 formulation and results

The formula 20 to the formula 22 respectively adopt xanthan gum, carbomer 940 and carbomer 21 as thickeners to prepare the emulsion with more liquid crystal, better centrifugal stability and better high-temperature stability of the emulsion prepared by using carbomer 940 and carbomer 21. In addition, carbomer 940 produces the largest amount of liquid crystal in the emulsion. HEC and EG are respectively adopted as thickening agents in the formula 23 and the formula 24, the liquid crystal quantity is low, ZEN and AVC are adopted as thickening agents in the formula 25 and the formula 26, the liquid crystal quantity of the prepared emulsion is medium, but the centrifugal stability is poor, and the high-temperature stability is good. It is stated that the network structure formed by the carbomer and xanthan gum thickeners contributes to the formation of the liquid crystalline structure. Therefore, carbomer 940 is preferred as the thickener in consideration of the amount of liquid crystal and the stability of the emulsion.

Example 4

In this embodiment, according to the results of the factors of the main emulsifier, the secondary emulsifier, the thickener and the like examined in examples 1 to 3 on the influence of the factors on the liquid crystal formation and the emulsion stability, a five-factor three-level orthogonal experiment is designed by taking the category of the main emulsifier, the dosage of the thickener, the ratio of the main emulsifier to the co-emulsifier, the ratio of the main emulsifier to the secondary emulsifier, and the dosage of the humectant as the examination factors to explain the influence of the factors on the liquid crystal formation and the emulsion stability and the optimization of the formula.

The primary emulsifiers used in this example were M68, M82 and M202; the secondary emulsifier is A165; the auxiliary emulsifier is cetostearyl alcohol; the thickening agent is carbomer 940; the humectant is glycerol. The factor levels of the orthogonal experiment of this example are shown in table 4.

Table 4 compositions of each protocol in example 4 and comparative examples

In the embodiment, the proportion of the emulsifier to the co-emulsifier and the proportion of the primary emulsifier to the secondary emulsifier are the mass percentage of each component in the formula. The design of the orthogonal experiment for this example is shown in table 5.

Table 5 detailed design and results of orthogonal experiments in example 4

The orthogonal experimental design method adopted in the embodiment analyzes the influence of various main influence factors on the liquid crystal quantity and the emulsion stability, and the results are shown in fig. 5 and the right three columns of table 5, so that the liquid crystal content of the liquid crystal emulsion formed by different composition ratios can be observed to be different, and the emulsion stability is also different.

From the analysis of the results of the orthogonal experiments, the results of all the protocols at each level of each factor were added and represented by K1, K2, and K3, respectively, and averaged. The range R for each factor is the maximum value minus the minimum value for each factor, as detailed in the last row of table 5. The magnitude of the range R can be derived, and the greater the range, the more important the factor. Thus, the primary and secondary order of factors is: the ratio of the emulsifier to the co-emulsifier > the type of the emulsifier > the ratio of the main emulsifier to the sub-emulsifier > the carbomer concentration > the glycerol concentration.

Analysis of results of orthogonal experiments

Values represent the effect of each level on the liquid crystal content. Taking factor A (kind of emulsifier) as an example,

at the maximum, it is indicated that the emulsifier type in the optimal formulation should be selected at level 3, M82. By analogy, the optimal group A can be obtained ₃ B ₁ C ₃ D ₂ E ₁ 。

Namely, the optimal formula 27 comprises the following components in percentage by mass: 3% of main emulsifier M82, 1% of secondary emulsifier A165, 1% of hexadecanol and octadecanol, 15% of white oil, 0.05% of carbomer 940, 10% of glycerol, 0.1% of EDTA2Na, 0.05% of triethanolamine, 0.2% of preservative and the balance of water.

Example 5

Generally, in addition to the conventional main ingredients (emollient, emulsifier, thickener, polyol humectant), other additives such as plant extracts, sodium pyrrolidone carboxylate or sodium hyaluronate are added to the lotion to improve the efficacy and comfort of the lotion after use. However, such additives contain a large amount of electrolyte or are electrolytes in themselves, which can reduce the viscosity of the emulsion, destroy the stability of the emulsion, and affect the amount of liquid crystal in the emulsion. Therefore, when the influence of the electrolyte on the emulsion stability and the emulsion liquid crystal content is examined, the effect that another electrolyte-resistant thickener is added on the basis of the original system as a secondary thickener is considered so as to improve the electrolyte resistance of the emulsion system.

For the above reasons, this example, based on the results of examples 1-3, takes the amount of the primary thickener, the kind of the secondary thickener, the ratio of the primary thickener and the secondary thickener, and the amount of the electrolyte as the factors to be considered, and designs a four-factor three-level orthogonal experiment to explain the influence of each factor on the formation of liquid crystal and the stability of emulsion and the optimization of the formula. The principle of selection requires that the primary thickener contributes the most to the liquid crystal quantity and the secondary thickener is electrolyte resistant and contributes to the liquid crystal quantity to some extent. In combination with the results of example 3, the primary emulsifier used in this example was M68; the main thickener is carbomer 940; the secondary thickener is carbomer 21, xanthan gum and SEPIMAX ZEN; sodium chloride is representative of the electrolyte. In the field of cosmetics, since a large number of raw materials containing electrolytes cannot be compared and verified one by one through experiments, the electrolytes in the examples were tested as represented by sodium chloride.

The factor levels of the orthogonal experiment of this example are shown in table 6.

Table 6 compositions of each protocol and comparative example in example 5

The orthogonal experimental design and results in this example are shown in table 7.

Table 7 specific design and results of the orthogonal experiments in example 5

The orthogonal experimental design method adopted in the embodiment analyzes the influence of various main influence factors on the liquid crystal quantity, the centrifugation and the high-temperature stability, and the results are shown in fig. 6, fig. 7 and fig. 8 and the right three columns of table 7, so that the liquid crystal emulsion formed by different thickener types has different liquid crystal contents and also has different emulsion centrifugation and high-temperature stability.

The magnitude relationship can be influenced by the magnitude of the range R (Table 7): electrolyte content > secondary thickener concentration > carbomer 940 concentration > secondary thickener species.

Analysis of the results of the orthogonal experiments in Table 7 gave the optimal set A ₁ B ₁ C ₂ D ₃ . Namely, the designed optimal formula (formula 28) comprises the following components: the main emulsifier M68 concentration is 3%, the cetostearyl alcohol concentration is 1%, the sub emulsifier A165 concentration is 1%, the white oil concentration is 15%, the main thickener carbomer 940 concentration is 0.1%, the sub thickener carbomer U21 concentration is 0.1%, the EDTA2Na concentration is 0.1%, the glycerin concentration is 5%, the triethanolamine concentration is 0.2%, the electrolyte concentration is 0.5%, the preservative concentration is 0.2%, and the balance is water. The emulsion has a liquid crystal content of 19.47%, and has poor centrifugal stability and good high-temperature stability. The optimized formula has a lower liquid crystal quantity than the results of the formulas No. 4B and No. 8B in the design. The number of liquid crystals and the stability of the emulsion are integrated, the formula number 4B is the final optimal selection, and the formula comprises the following components: the concentration of a main emulsifier M68 is 3%, the concentration of cetostearyl alcohol is 1%, the concentration of a secondary emulsifier A165 is 1%, the concentration of white oil is 15%, the concentration of a main thickener carbomer 940 is 0.15%, the concentration of a secondary thickener carbomer U21 is 0.1%, the concentration of EDTA2Na is 0.1%, the concentration of glycerol is 5%, the concentration of triethanolamine is 0.25%, the concentration of electrolyte is 0.5%, the concentration of preservative is 0.2%, and the balance is deionized water.

In addition, it was found in the experiment that the stability of the liquid crystal content of the emulsion system was affected by the electrolyte in the system, and the results are shown in fig. 7. FIG. 7 shows that the content of liquid crystal in the 4B case emulsion gradually decreases with time, which seriously affects the use effect of the emulsion. Through experimental comparison, the liquid crystal content of the emulsion system without the electrolyte is relatively stable. Therefore, in the presence of an electrolyte, how to improve the stability of the liquid crystal becomes a big problem and needs to be solved through a series of experiments.

Example 6

The results of example 4 show that the type of emulsifier has a large influence on the amount of liquid crystals, and that different emulsifiers have different resistances to electrolytes. Thus, the experimental design of this example was identical to that of example 5, except that M82 was used as the primary emulsifier. The results of the orthogonal experiments in this example are shown in fig. 6, 7, 8 and table 8.

Table 8 specific design and results of the orthogonal experiments in example 6

Analysis of the results of the orthogonal experiments in Table 8 gave the optimal set A ₂ B ₁ C ₂ D ₃ . Namely, the optimal formula 13B comprises the following components: the concentration of a main emulsifier M82 is 3%, the concentration of cetostearyl alcohol is 1%, the concentration of a secondary emulsifier A165 is 1%, the concentration of white oil is 15%, the concentration of a main thickener carbomer 940 is 0.15%, the concentration of a secondary thickener carbomer U21 is 0.1%, the concentration of glycerin is 5%, the concentration of EDTA2Na is 0.1%, triethanolamine is 0.25%, the concentration of a preservative is 0.2%, the content of an electrolyte is 0.5%, and the balance is water. The liquid crystal content of the emulsion is 11.45 percent, and the emulsion has good high-temperature stability. The emulsion liquid crystal stability is shown in FIG. 8.

From the results, it can be observed that the formulations 21 and 27 without the added electrolyte have good liquid crystal stability, and the amount of liquid crystal does not change significantly after 3 months. The initial liquid crystal content of the formula 4B is higher, the quantity of liquid crystals is gradually reduced along with the change of time, and the electrolyte in the system can gradually destroy the liquid crystal structure of the emulsion taking M68 as the main emulsifier, so that the liquid crystal stability of the emulsion is poor. The liquid crystal quantity of the formula 13B is basically unchanged after 3 months, and the liquid crystal stability is good. Therefore, if the emulsion system contains more electrolyte, the M82 emulsifier can provide better liquid crystal stability, i.e., formula 13B is the best choice. Formulation 27 is the preferred choice for the case where no electrolyte is present.

Example 7

The embodiment provides specific formula cases based on the optimal formula of the embodiments 4-6 in combination with practical applications, which are shown in tables 9-10.

TABLE 9 some typical formulation cases of the present invention

TABLE 10 some typical formulation cases provided by the present invention

These liquid crystal emulsions can be prepared as follows:

(1) heating the main emulsifier, the secondary emulsifier, the co-emulsifier and the emollient to 75-85 ℃ (preferably 80 ℃) and stirring uniformly to form a uniform oil phase for later use;

(2) mixing deionized water, humectant and main thickener (secondary thickener is added when electrolyte is contained in the formula), stirring uniformly, and heating to 75-85 deg.C (preferably 80 deg.C) to form uniform water phase;

(3) directly adding the water phase in the step (2) into the oil phase in the step (1), and then homogenizing at the rotating speed of 4500-5500 rpm for 3-8 minutes (preferably 5000 rpm for 5 minutes), and keeping the temperature at 75-80 ℃ (preferably 75 ℃);

(4) slowly cooling and stirring after the emulsion is formed, cooling to 45-55 ℃ (preferably 50 ℃), sequentially adding other residual raw materials, and continuously stirring for 3-8 minutes (preferably 5 minutes);

(5) stopping stirring when the temperature is reduced to 35-45 ℃ (preferably 40 ℃), and finishing processing to obtain liquid crystal emulsion;

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents and are included in the scope of the present invention.

Claims

1. A liquid crystal emulsion is characterized in that: the feed is prepared from the following raw materials in percentage by mass: 1-3% of a main emulsifier, 0.5-2.0% of a secondary emulsifier, 0.5-3.0% of a co-emulsifier, 0.05-0.40% of a main thickener, 5-12% of a humectant, 10-20% of an emollient and the balance of deionized water;

the primary emulsifier is an alkyl glycoside, with the trade name MONTANOV 68, i.e. a mixture of cetearyl alcohol and cetearyl glucoside, or MONTANOV82, i.e. a mixture of cetearyl alcohol and coco glucoside; the secondary emulsifier is a mixture of glyceryl stearate and PEG-100 stearate, and has a trade name of SIMULSOL 165 and a model number of A165; the auxiliary emulsifier is cetostearyl alcohol;

the main thickener is carbomer 940;

the mass part ratio of the primary emulsifier to the secondary emulsifier to the auxiliary emulsifier is 3: 1: 1.

2. a liquid crystal emulsion is characterized in that: the feed is prepared from the following raw materials in percentage by mass: 1-3% of a main emulsifier, 0.5-2.0% of a secondary emulsifier, 0.5-3.0% of a co-emulsifier, 0.05-0.20% of a main thickener, 0.05-0.20% of a secondary thickener, 0.05-5% of other conventional additives, 5-12% of a humectant, 10-20% of an emollient and the balance of deionized water, wherein the other conventional additives contain electrolytes;

the mass ratio of the primary emulsifier to the secondary emulsifier to the co-emulsifier is 3: 1: 1;

the main thickener is carbomer 940, the secondary thickener is xanthan gum or carbomer U21, and the mass part ratio of carbomer 940 to xanthan gum is 0.2: 0.15, the mass part ratio of the carbomer 940 to the carbomer U21 is 0.15: 0.1.

3. the liquid crystal emulsion according to claim 2, wherein: the other conventional auxiliary agents comprise one or more of preservatives, essences, chelating agents, pH regulators and functional additives.

4. The liquid crystal emulsion according to claim 3, wherein: the preservative is a mixture of phenoxyethanol, methyl hydroxybenzoate, ethylparaben and ethylhexylglycerin, and is sold under the trade name euxyl K350 and produced in Shumei of Germany; the chelating agent is EDTA disodium; the pH value regulator is triethanolamine; the functional additive is one or more of commercially available plant extract, hyaluronic acid and its derivatives, ceramide, sodium pyrrolidone carboxylate and dipotassium glycyrrhizinate.

5. A liquid-crystal emulsion according to claim 1 or 2, characterized in that: the humectant is glycerol, or the humectant is a mixture of glycerol and trehalose, or the humectant is a mixture of glycerol and 1, 3-butanediol; the emollient is white oil.