CN109679092B

CN109679092B - Preparation method of cosmetic-grade sodium polyaspartate

Info

Publication number: CN109679092B
Application number: CN201811631919.5A
Authority: CN
Inventors: 曹辉; 段永豪; 谭天伟; 王宇灿; 邓逸琳
Original assignee: Beijing University of Chemical Technology
Current assignee: Beijing University of Chemical Technology
Priority date: 2018-12-28
Filing date: 2018-12-28
Publication date: 2022-01-18
Anticipated expiration: 2038-12-28
Also published as: CN109679092A

Abstract

The invention relates to a preparation method of cosmetic grade sodium polyaspartate. The method takes L-aspartic acid as a raw material, adopts mixed solution of phosphoric acid aqueous solution and citric acid as a catalyst, and prepares the cosmetic grade sodium polyaspartate by the processes of polymerization, crushing, washing separation, drying, hydrolysis, filtration, purification, sterilization, compounding or drying and the like. The cosmetic grade sodium polyaspartate has the molecular weight of 2000-100000D, high purity, low conductivity, light color, no special odor and high safety, meets the quality and sanitary standard of cosmetics, and is suitable for being applied to the field of daily chemicals, especially cosmetics.

Description

Preparation method of cosmetic-grade sodium polyaspartate

Technical Field

The invention belongs to the technical field of biochemical synthesis, and particularly relates to a preparation method of cosmetic-grade sodium polyaspartate.

Background

Polyaspartic acid is a multifunctional biopolymer material which is a homopolymeric amino acid taking aspartic acid as a monomer, each monomer contains a free carboxyl and a peptide bond, has extremely strong functions of moisture retention, chelation, dispersion, adsorption and the like, and is widely applied to the fields of water treatment agents, fertilizer synergists, metal cutting fluids, daily chemicals, detergents, dispersants, chelating agents, water retention agents and the like.

The preparation methods of polyaspartic acid in different fields are various, and Chinese patent CN106220846A discloses polyaspartic acid for a fertilizer synergist and a preparation method and application thereof. Patent CN102674569A discloses a preparation method of polyaspartic acid scale inhibitor. Patent CN103113584A discloses a method for preparing environment-friendly polyaspartic acid for ternary combination flooding used in oil field. However, the prior art does not relate to a preparation method and application of polyaspartic acid in the field of cosmetics, and research on application technology of polyaspartic acid in cosmetics is lacked.

Polyaspartic acid is used as an efficacy cosmetic additive, mainly in the form of polyaspartic acid sodium salt. At present, in the field of application of sodium polyaspartate, the obtained product is not purified, has high impurity content, high ion concentration, dark color and large smell, greatly influences the sense and formula system of cosmetics, and is not suitable for application in the field of cosmetics.

Therefore, there is a need to develop a production process of polyaspartic acid sodium suitable for cosmetic applications, and the prepared polyaspartic acid sodium product has high safety, high purity, light color, small odor and high stability in a cosmetic formulation system.

Disclosure of Invention

The invention aims to solve the technical problem of the prior art and provides a preparation method of cosmetic grade sodium polyaspartate. The product prepared by the method is easy to separate and purify, and the obtained sodium polyaspartate product has high purity, low conductivity, light color, no special odor, controllable molecular weight and high stability, and meets the quality and sanitary standards of cosmetics.

To this end, the present invention provides, in a first aspect, a process for the preparation of cosmetic grade sodium polyaspartate comprising:

step A, carrying out polymerization reaction by taking aspartic acid as a raw material under the action of an acid catalyst to obtain a polymerization product;

b, crushing the polymerization product, washing the crushed product with an aqueous solution of alkaline salt and pure water respectively, filtering and drying to obtain a washed polymerization product;

step C, adding alkali liquor into the washed polymerization product to perform hydrolysis reaction to obtain a hydrolysis product;

step D, separating and purifying the hydrolysate to obtain a purified product;

e, carrying out decoloring treatment on the purified product to obtain a decolored product;

and F, sterilizing the decolorized product, and drying to obtain the cosmetic grade sodium polyaspartate.

According to some preferred embodiments of the present invention, in step F, the decolorized product is sterilized, added with preservative ingredients, and dried to obtain a cosmetic grade sodium polyaspartate.

In some embodiments of the invention, in step A, the molar ratio of aspartic acid to acidic catalyst is 1: 0.01 to 2.0, preferably 1: 0.01 to 1.0, more preferably 1: 0.025 to 0.1.

In the present invention, the aspartic acid is L-aspartic acid.

In the invention, the acidic catalyst is a mixed solution of phosphoric acid aqueous solution and citric acid.

In some embodiments of the invention, the aqueous phosphoric acid solution has a concentration of 70 wt% to 85 wt%.

In some embodiments of the invention, the citric acid has a purity of 99% or more.

In some embodiments of the present invention, the mass ratio of phosphoric acid to citric acid in the mixed solution of phosphoric acid aqueous solution and citric acid is (0.1-1) to 1, preferably (0.2-0.8) to 1.

According to some embodiments of the present invention, in step A, the temperature of the polymerization reaction is 120-200 ℃, preferably 150-170 ℃.

According to some embodiments of the invention, in step A, the polymerization time is between 1 and 6h, preferably between 2 and 4 h.

According to some embodiments of the invention, in step A, the pressure of the polymerization reaction is between-0.02 and 0.095MPa, preferably between-0.05 and 0.08 MPa.

In some preferred embodiments of the present invention, the temperature of the polymerization reaction is subjected to at least 1 gradient decay during the polymerization reaction, preferably, the temperature of the polymerization reaction is subjected to 1-2 gradient decays during the polymerization reaction.

In some preferred embodiments of the invention, the polymerization reaction temperature decay has a magnitude of 5 to 20 ℃.

In some preferred embodiments of the invention, the decay time is 1-2h apart.

According to some embodiments of the invention, in step B, the polymerization product is pulverized to 40 to 200 mesh, preferably 60 to 200 mesh.

In the present invention, the alkali salt includes sodium carbonate and/or sodium bicarbonate.

In some embodiments of the present invention, in step B, the mass concentration of the aqueous solution of the alkaline salt is 1% to 20%, and more preferably 2% to 15%.

In the invention, the alkali liquor is an aqueous solution of sodium hydroxide.

In some embodiments of the invention, the aqueous solution of sodium hydroxide has a mass concentration of 10% to 50%, preferably 20% to 40%.

According to some embodiments of the invention, in step C, the temperature of the hydrolysis reaction is between 30 and 60 ℃.

According to some embodiments of the invention, in step C, the hydrolysis reaction time is between 0.5 and 6h, preferably between 1 and 2 h.

According to some embodiments of the invention, in step C, the stirring speed during the hydrolysis reaction is 70-120 rpm.

In the present invention, the separation and purification method in step D includes a physical separation method and/or a chemical separation method, and preferably a physical separation method.

In some embodiments of the invention, the physical separation method comprises one or more of filtration, ultrafiltration, nanofiltration, ion exchange and electrodialysis.

According to some embodiments of the invention, in step E, the decolorizing treatment is performed with a decolorizing agent.

In some embodiments of the invention, the decolorizing agent includes one or more of activated carbon, silica, aluminum sulfate, and PA decolorizing agent (polyaluminum chloride).

In some embodiments of the invention, the temperature of the decolorization treatment is 40 to 70 ℃, preferably 50 to 60 ℃.

In some embodiments of the invention, the time of the decolorization treatment is 0.5 to 2 hours.

In the present invention, high temperature or irradiation is used for sterilization.

In some embodiments of the invention, the temperature of the sterilization process is 80-100 ℃.

In some embodiments of the invention, the time of the sterilization treatment is 20-120 min.

In the invention, the antiseptic component comprises one or more of imidazolidinyl urea, methyl paraben, propyl paraben, phenoxyethanol, ethylhexyl glycerol, butanediol, pentanediol, hexanediol, octanediol, p-hydroxyacetophenone and caprylhydroxamic acid.

In some embodiments of the present invention, the preservative component is used in an amount of 0.1 wt% to 10 wt%, preferably 0.1 wt% to 5 wt%, based on the total weight of the decolorized product.

The second aspect of the invention provides a cosmetic grade polyaspartic acid sodium, the molecular weight of which is 2000-100000Da, preferably 3000-50000 Da; the conductivity of the 1 wt% aqueous solution of the sodium polyaspartate is 500-3000 mu s/cm, preferably 700-2000 mu s/cm; the color of the 20 wt% aqueous solution of sodium polyaspartate is 50-700 deg., preferably 100-500 deg.

In a third aspect, the present invention provides a use of another cosmetic grade sodium polyaspartate prepared according to the method of the first aspect of the present invention or the cosmetic grade sodium polyaspartate provided according to the second aspect of the present invention in the preparation of skin care products, washing products and color cosmetics.

The preparation method of the cosmetic grade sodium polyaspartate provided by the invention takes L-aspartic acid as a raw material, adopts mixed solution of phosphoric acid aqueous solution and citric acid as a catalyst, and prepares the cosmetic grade sodium polyaspartate by the processes of polymerization, crushing, washing separation, drying, hydrolysis, filtering, purification, sterilization, compounding or drying and the like. According to the method, a compound catalyst is adopted to replace a traditional single catalyst in the polymerization process, the obtained product has small molecular acting force and low viscosity, the catalyst is easy to be completely separated under the washing action of alkaline salt and pure water, the subsequent process is easier to carry out, the molecular weight of the finally obtained sodium polyaspartate is between 2000-100000Da, the purity is high, the conductivity is low, the color is light, no special smell is generated, the safety is high, the cosmetic quality and sanitary standard is met, and the method is suitable for being applied to the field of daily chemicals.

Drawings

For the present invention to be readily understood, the following description is made with reference to the accompanying drawings.

Fig. 1 shows the results of the use effect test of the skin conditioning essence of the present invention, which uses the cosmetic grade sodium polyaspartate as the functional component, wherein a is fresh pigskin (as the control sample) which is not treated with the skin conditioning essence; and b is the pigskin soaked by the skin conditioning essence.

Fig. 2 is a scanning electron microscope image of damaged hair that has not been treated with the hair conditioning nutritional solution of the present invention with cosmetic grade sodium polyaspartate as the functional ingredient.

Fig. 3 is a scanning electron microscope image of damaged hair treated by the hair conditioning nutrient solution taking cosmetic grade sodium polyaspartate as an effective component for 15 days.

Detailed Description

In order that the invention may be readily understood, a detailed description of the invention is provided below. However, before the invention is described in detail, it is to be understood that this invention is not limited to particular embodiments described. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

Where a range of values is provided, it is understood that each intervening value, to the extent that there is no stated or intervening value in that stated range, to the extent that there is no such intervening value, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges, and are also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where a specified range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.

Unless otherwise defined, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, the preferred methods and materials are now described.

I. Term(s) for

The term "basic salt" as used herein means a salt in which an aqueous solution of the salt is basic.

The term "water" as used herein means deionized water, ultrapure water or distilled water unless otherwise specified.

Embodiments of

Polyaspartic acid is a water-soluble polypeptide, contains the structural characteristics of active groups such as peptide bonds, carboxyl and the like, has extremely strong chelating, dispersing, adsorbing and other effects, and is widely applied to the fields of fertilizer synergism, industrial water treatment, metal cutting fluid, daily chemicals, oil field water injection aids for oil extraction and the like. In addition, the polyaspartic acid has wide application prospect in the aspects of detergents, super absorbent resins, coal water slurry additives, photochemical products and the like. However, the prior art does not relate to a preparation method and application of polyaspartic acid in the field of cosmetics, and research on application technology of polyaspartic acid in cosmetics is lacked.

When the polyaspartic acid is used as an efficacy type cosmetic additive, the polyaspartic acid is mainly in the form of sodium polyaspartate. As mentioned above, the polyaspartic acid sodium obtained by the existing production process of polyaspartic acid sodium is not purified, the product has high impurity content, dark color and large smell, and is not suitable for being applied in the field of cosmetics.

Based on this, the inventor of the present application has conducted a great deal of research on the preparation method of cosmetic grade sodium polyaspartate, and creatively found that, by using L-aspartic acid as a raw material and using a mixed solution of phosphoric acid aqueous solution and citric acid as a catalyst, a polymerization product obtained by performing a polymerization reaction has a small molecular force and a low viscosity, and is easy to completely separate the catalyst under the washing action of alkaline salt and pure water, so that the subsequent processes are easier to perform, and thus, by performing the processes of polymerization reaction, pulverization, washing, hydrolysis reaction, filtration, separation and purification, decolorization, sterilization, compounding, drying, etc., cosmetic grade sodium polyaspartate with high purity, molecular weight in a controllable range of 2000 + 100000Da, light color, no special odor, and good stability can be obtained.

Accordingly, the process for the preparation of cosmetic grade sodium polyaspartate according to the first aspect of the present invention comprises:

step D, separating and purifying the hydrolysate to obtain a purified product;

The polymerization product obtained after the polymerization reaction of the aspartic acid and the acidic catalyst in the step A is a mixture of Polysuccinimide (PSI) and the catalyst.

In the present invention, the aspartic acid is L-aspartic acid.

In the invention, the acidic catalyst is a mixed solution of phosphoric acid aqueous solution and citric acid. In some embodiments of the invention, the aqueous phosphoric acid solution has a concentration of 70 wt% to 85 wt%, preferably 85 wt%; the purity of the citric acid is more than or equal to 99 percent.

It will be understood by those skilled in the art that when the acidic catalyst is a mixture of aqueous phosphoric acid and citric acid, the molar ratio of aspartic acid to the acidic catalyst is the total molar ratio of aspartic acid to the acidic catalyst, i.e., the ratio of the number of moles of aspartic acid to the total number of moles of phosphoric acid and citric acid.

In some embodiments of the invention, the polymerization conditions in step a are: the temperature is 120 ℃ and 200 ℃, the reaction time is 1-6h, and the reaction pressure is-0.02-0.095 MPa.

In some particularly preferred embodiments of the present invention, the polymerization conditions in step a are: the temperature is 150 ℃ and 170 ℃, the reaction time is 2-4h, and the reaction pressure is-0.05-0.08 MPa.

In some preferred embodiments of the invention, the decay time is 1-2h apart.

In some embodiments of the present invention, in step B, the mass concentration of the aqueous solution of the alkaline salt is 1% to 20%, more preferably 2% to 15%, and still more preferably 2%.

In some particularly preferred embodiments of the invention, after washing the comminuted product with an alkaline solution, further washing with deionized water, filtering and drying at a drying temperature of 80 to 100 ℃ and a dry matter moisture content of less than 10% by weight after drying.

In some embodiments of the present invention, the washing equipment in step B is a stirring vacuum suction filter, a centrifuge, a filter press, etc. which are commonly used in the art.

In the invention, the alkali liquor is an aqueous solution of sodium hydroxide.

In some preferred embodiments of the present invention, in step B, washing is carried out until the pH of the aqueous solution is stabilized at 7 to 8, so that the residual catalyst can be thoroughly washed away.

In some specific embodiments of the present invention, when the hydrolysis reaction is performed in step C, the mass ratio of PSI to the aqueous sodium hydroxide solution is 1 to (2-8), and the solid content of the aqueous sodium polyaspartate solution is 20 wt% to 50 wt%.

In the invention, the hydrolysate of the sodium polyaspartate obtained after the hydrolysis reaction in the step C contains solid impurities, small molecular salts, excessive alkali and other impurities, and needs to be separated and purified.

In some embodiments of the present invention, the hydrolysate of sodium polyaspartate obtained after hydrolysis in step C has some solid impurities and is filtered.

In some embodiments, step D is performed to filter the hydrolysate, and due to the viscosity of the hydrolysate, diatomite and/or activated carbon is used as a filter aid, preferably diatomite with 50-200 meshes, and the filter cloth is 100-500 meshes, so that a good filtering effect can be achieved.

In other embodiments, step D filters the hydrolysate using a vertical filter press, a horizontal filter press or a centrifuge.

In some preferred embodiments, a filter aid such as diatomaceous earth or activated carbon may be added during the filtering of the hydrolysate in step D to improve the filtering efficiency of the filtrate, filter out fine suspended matters, and ensure the clarity of the filtrate.

In some further specific embodiments of the present invention, the filtered polyaspartic acid sodium aqueous solution contains some small molecular salts and excessive alkali, and other impurities, and needs to be separated and purified.

In some preferred embodiments, step D is further separated and purified by membrane separation to remove impurities such as small molecule salts and excess alkali.

In some more preferred embodiments, the hollow fiber ultrafiltration membrane is used for further separation and purification in step D to remove impurities such as small molecular salts and excessive alkali, and the specification of the hollow fiber ultrafiltration membrane can be adjusted as required.

The sodium polyaspartate is rich in carbon source and nitrogen source, and provides good environment for the growth and propagation of microorganisms. If the sodium polyaspartate which is not sterilized is used in the cosmetic industry, the quality of the product is greatly influenced. Therefore, the present invention sterilizes the decolorized product in step F.

The sterilization treatment method in the present invention is not particularly limited, and a sterilization method which is conventional in the art may be employed, and for example, a high-temperature sterilization treatment and/or a radiation sterilization treatment may be employed, and a high-temperature sterilization treatment is preferably employed.

In some embodiments of the invention, the temperature of the autoclaving process is in the range of 80 to 100 ℃.

In some embodiments of the invention, the time for the autoclaving process is 20-120 min.

In some embodiments of the present invention, the temperature for sterilizing the decolorized product after filtration is 80-100 deg.C for 20-120 min.

In some embodiments of the present invention, the preservative component is used in an amount of 0.1 wt% to 10 wt%, preferably 0.1 wt% to 5 wt%, based on the total weight of the decolorized product. The result of the evaluation of the preservative efficacy of the ISO 11930-2012 cosmetic product shows that the liquid sodium polyaspartate product can well inhibit the growth of microorganisms after the preservative component is added.

According to some preferred embodiments of the invention, step F is dried using centrifugal spray drying.

In some preferred embodiments of the present invention, the centrifugal spray drying has an inlet temperature of 140-200 ℃ and an outlet temperature of 75-95 ℃.

According to further preferred embodiments of the present invention, step F is dried by freeze-drying.

In some preferred embodiments of the invention, the temperature of the freeze-drying is from-50 to-10 ℃.

The preparation method of the cosmetic grade sodium polyaspartate takes L-aspartic acid as a raw material, adopts a mixed solution of phosphoric acid aqueous solution and citric acid as a catalyst, and adopts the processes of polymerization reaction, crushing, washing, hydrolysis reaction, filtering, separation and purification, decoloration, sterilization, compounding, drying and the like, the obtained sodium polyaspartate has high purity, the molecular weight is in the controllable range of 2000-100000Da, preferably 3000-50000Da, the color is colorless to light yellow, no special odor and good stability, the conductivity of the aqueous solution of the sodium polyaspartate with the content of 1 wt% is 500-3000 mu s/cm, preferably 700-2000 mu s/cm, the chroma of the aqueous solution of the sodium polyaspartate with the content of 20 wt% is 50-700 degrees, preferably 100-500 degrees, the safety index conforms to the technical specification 2015 for cosmetic safety, and the safety to human body is high, can be used in skin care products, washing products and cosmetics.

The inventor creatively discovers that the purity of the obtained sodium polyaspartate is high, the molecular weight is in a controllable range of 2000 plus 100000Da, the color is colorless to faint yellow, no special smell is generated, the stability is good, the quality and sanitary standard of cosmetics are met, the safety to a human body is high, and the sodium polyaspartate can be used for skin care products, washing products and color cosmetics.

The molecular weight of the polyaspartic acid is detected by liquid chromatography (Shimadzu LC-20A).

In the invention, the chromaticity of the sodium polyaspartate aqueous solution is detected by a colorimeter (Hanna/HI 96727) according to GB/T5750.4-2006 (platinum-cobalt colorimetry).

In the invention, the conductivity of the sodium polyaspartate aqueous solution is detected by a conductivity meter (Mettler/FE 30) according to GB/T11007-2008 (conductivity meter test method).

In the invention, the purity of the polyaspartic acid is detected by adopting liquid chromatography and a liquid chromatograph (Shimadzu LC-20A).

The skin moisture content in the present invention was measured using a skin moisture content tester (Comeometer) (CM825, Courage and Khazaka, germany).

The amount of skin water loss in the present invention was measured using a skin water loss measuring instrument (Vapometer) (TM300-MDD, Courage and Khazaka, Germany).

The surface of the hair was tested using an electronic scanning electron microscope (SU1510, hitachi high and new technologies).

Examples

In order that the present invention may be more readily understood, the following detailed description will proceed with reference being made to examples, which are intended to be illustrative only and are not intended to limit the scope of the invention. The starting materials or components used in the present invention may be commercially or conventionally prepared unless otherwise specified.

Example 1: preparation of cosmetic grade sodium polyaspartate

Heating 2000 g of L-aspartic acid, 20 g of phosphoric acid (aqueous solution of phosphoric acid, 85 wt%) and 40 g of citric acid (purity is more than or equal to 99%) to 170 ℃ for reaction for 2 hours to obtain white polysuccinimide powder or particles, crushing the white polysuccinimide powder or particles, sieving the crushed polysuccinimide powder by a 60-mesh sieve for later use, washing the white polysuccinimide powder or particles by using 2 wt% of sodium bicarbonate aqueous solution, washing the ground polysuccinimide powder or particles to be neutral, washing the neutral polysuccinimide powder or particles by using water, drying the washed polysuccinimide powder or particles in an oven at 80 ℃ for later use, adding 1000 g of the dried polysuccinimide powder into 4000g of 40% of sodium hydroxide aqueous solution with the mass fraction of 4000g, filtering the mixture by using 200-mesh filter cloth, performing ultrafiltration by using a hollow fiber membrane with the molecular weight cutoff of 3000Da, wherein the amount of the pure water is 3 times that of the aqueous solution before filtration, and concentrating and adding water for 2 times. Adding 0.5 wt% of active carbon into the obtained concentrated solution, decoloring for 0.5 h at the temperature of 50 ℃, filtering, sterilizing for 20min at the temperature of 80 ℃, and adding 0.5% of imidazolidinyl urea by mass ratio to obtain a sodium polyaspartate aqueous solution with a certain concentration and a molecular weight of 3000-10000 Da. The color is colorless to light yellow, and the odor is not characteristic.

Example 2: preparation of cosmetic grade sodium polyaspartate

Heating 2000 g of L-aspartic acid, 80 g of phosphoric acid (aqueous solution of phosphoric acid, 85 wt%) and 160 g of citric acid (purity is more than or equal to 99%) to 200 ℃ for reaction for 4 hours to obtain light yellow polysuccinimide powder or particles, crushing the powder, sieving the powder by a 60-mesh sieve for later use, washing the powder by using 2 wt% of sodium bicarbonate aqueous solution, washing the powder to be neutral, washing the powder by using water, drying the powder in an oven at 80 ℃ for later use, taking 1000 g of dried polysuccinimide powder, adding 5000g of 40% of sodium hydroxide aqueous solution by mass fraction, filtering the powder by using 200-mesh filter cloth, carrying out ultrafiltration by using a hollow fiber membrane with molecular weight cut-off of 10000Da, adding 5 times of pure water to the solution before filtration, adding 0.5 wt% of active carbon to the obtained concentrated solution, decoloring the concentrated solution at the temperature of 60 ℃ for 0.5 hours, sterilizing the concentrated solution at the temperature of 80 ℃ for 20 minutes after filtration, adding imidazolidinyl urea with the mass ratio of 0.5% to obtain the sodium aspartate aqueous solution with a certain concentration, the molecular weight is 30000-50000 Da. The color is light yellow to yellow, and the product has no characteristic odor.

Example 3: preparation of cosmetic grade sodium polyaspartate

Heating 2000 g of L-aspartic acid, 20 g of phosphoric acid (85 wt percent of aqueous solution of phosphoric acid) and 40 g of citric acid (purity is more than or equal to 99 percent) to 200 ℃ for reaction for 2 hours to obtain white polysuccinimide powder or particles, crushing the white polysuccinimide powder and passing through a 60-mesh screen for standby, washing the white polysuccinimide powder and the citric acid by using 2wt percent of aqueous solution of sodium bicarbonate, washing the white polysuccinimide powder and the citric acid to be neutral, then washing the neutral polysuccinimide powder by using water, drying the white polysuccinimide powder and the white polysuccinimide powder in an oven at 80 ℃ for standby, taking 1000 g of the dried polysuccinimide powder, adding 4000g of aqueous solution of sodium hydroxide with the mass fraction of 40 percent, filtering the mixture by using 200-mesh filter cloth, carrying out ultrafiltration by using a hollow fiber membrane with the molecular weight of 3000Da, adding 3 times of pure water to the solution before filtration, adding 0.5wt percent of active carbon to the obtained concentrated solution, carrying out decolorization at 50 ℃, sterilizing the mixture for 20 minutes at 80 ℃, carrying out centrifugal spray drying, obtaining white polysuccinimide powder with the molecular weight of 3000 plus 10000Da, has no characteristic odor.

Example 4: preparation of cosmetic grade sodium polyaspartate

Heating 2000 g L-aspartic acid, 80 g phosphoric acid (85 wt% of aqueous solution of phosphoric acid) and 160 g citric acid (purity is more than or equal to 99%) to 200 ℃ for reaction for 4 hours to obtain white polysuccinimide powder or particles, crushing the white polysuccinimide powder or particles, sieving the crushed white polysuccinimide powder by a 60-mesh sieve for later use, washing the white polysuccinimide powder or particles by using 2 wt% of aqueous solution of sodium bicarbonate, washing the neutral polysuccinimide powder or particles by using water, drying the dried polysuccinimide powder in an oven at 80 ℃ for later use, adding 1000 g of the dried polysuccinimide powder into 40% of aqueous solution of sodium hydroxide, filtering the mixture by using 200-mesh filter cloth, performing ultrafiltration by using a hollow fiber membrane with the molecular weight cut-off of 10000Da, wherein the amount of the pure water is 5 times of the solution before filtration, adding 0.5 wt% of active carbon into the obtained concentrated solution, performing decolorization at 60 ℃, sterilizing the filtered solution at 80 ℃ for 20 minutes, performing centrifugal spray drying to obtain white polysuccinimide powder with the molecular weight of 30000 and 50000Da, has no characteristic odor.

Example 5: skin conditioning essence prepared from cosmetic grade sodium polyaspartate and subjected to effect test

1. Skin conditioning essence formula

The formula of the skin conditioning essence taking the sodium polyaspartate as the efficacy agent comprises the following components: the essence comprises the following components in percentage by total weight:

2. effect testing

(1) Skin moisture content test

26 volunteers were selected, the moisturizing liquid prepared by the above formulation was applied on the skin surface of the volunteer under the conditions of temperature 22 + -1 deg.C and humidity (50 + -5%), and the skin moisture parameters of the volunteer were measured at 0h, 2h, 4h and 8h using a skin moisture content tester (Comeometer) (CM825, Courage and Khazaka, Germany) to obtain the moisture content change of the skin of the volunteer within 8h, and the results are shown in Table 1.

TABLE 1

As can be seen from Table 1, the moisture content of the skin of the volunteers is remarkably increased at 2h, 4h and 8h, which shows that the moisturizing liquid taking the sodium polyaspartate as the main agent has obvious moisturizing effect. The skin moisture parameter of the formulation without adding polyaspartic acid sodium is reduced by 7-9%.

(2) Skin Water loss test

12 volunteers were selected, and the moisturizing liquid prepared by the above formulation was applied to the skin surface of the volunteers under the conditions of temperature of 22. + -. 1 ℃ and humidity (50. + -. 5%), and the skin water loss of the volunteers was measured at 0h, 2h, 4h and 8h using a skin water loss measuring instrument (Vapometer) (TM300-MDD, Courage and Khazaka, Germany), to obtain the skin water loss change of the volunteers within 8h, and the results are shown in Table 2.

TABLE 2

As can be seen from Table 2, the water loss of the skin of the volunteers is remarkably reduced at 2h, 4h and 8h, which indicates that the essence taking the sodium polyaspartate as the main agent has obvious water-locking effect and can improve the barrier function of the skin. The skin water loss of the formula without adding sodium polyaspartate increases by 1-2 (g/m)²·h)

(3) The animal experiment method is as follows: soaking fresh Corii Sus Domestica at 15 deg.C with 35% RH (humidity) for 2 hr, taking out, drying, and standing for 2 hr, with the front and back images shown in FIG. 1.

In fig. 1, a is a fresh pigskin which is not treated by the nourishing essence, and b is a pigskin which is soaked by the nourishing essence, and the result shows that the nourishing essence taking the sodium polyaspartate as the efficacy agent has good affinity with the skin, can soften the skin, can fill the skin cells, can inhibit skin contraction, can increase skin elasticity, and can improve the skin appearance.

Example 6: shampoo is prepared by adopting cosmetic-grade sodium polyaspartate and effect test is carried out

1. Shampoo formula

The shampoo comprises the following components in percentage by total weight of the shampoo:

2. effect testing

The shampoo formula and the shampoo formula without adding sodium aspartate are respectively used for carrying out half-head experiments, and the following test items are subjectively evaluated by a professional evaluator, so that the obtained results are shown in table 3, wherein the numbers represent the number of people.

TABLE 3

The statistical results in Table 3 show that when the shampoo with the sodium polyaspartate as the efficacy agent is used for washing hair, the foam is fine and smooth, and the combing property, the glossiness and the antistatic effect of the dried hair are obviously improved.

Example 7: hair conditioning nutrient solution prepared from cosmetic-grade sodium polyaspartate and subjected to effect test

1. Hair conditioning nutrient solution formula

The hair conditioning nutritional liquid comprises the following components based on the total weight of the hair conditioning nutritional liquid:

2. effect testing

Volunteers with hair perming and damaging effects use the hair care solution containing sodium polyaspartate as main agent, and test the hair care solution by using an electronic scanning electron microscope (SU1510, Hitachi high tech Co., Ltd.) before and after 15 days, and the comparison effect is shown in figures 2 and 3.

FIG. 2 is a scanning electron micrograph of damaged hair not treated with the hair conditioner, and FIG. 3 is a scanning electron micrograph of damaged hair treated with the hair conditioner after 15 days. The results show that the hair care liquid using the polyaspartic acid sodium as the main agent can repair hair damage caused by various reasons.

It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.

Claims

1. A method for preparing cosmetic grade sodium polyaspartate comprising:

step D, separating and purifying the hydrolysate to obtain a purified product;

step F, sterilizing the decolorized product, and drying to obtain cosmetic-grade sodium polyaspartate;

in the step A, the molar ratio of the aspartic acid to the acidic catalyst is 1 (0.025-0.1);

the acid catalyst is a mixed solution of phosphoric acid aqueous solution and citric acid, and the mass ratio of phosphoric acid to citric acid in the mixed solution of phosphoric acid aqueous solution and citric acid is (0.1-1): 1;

the molecular weight of the cosmetic grade sodium polyaspartate is 2000-100000 Da; the conductivity of 1 wt% aqueous solution of cosmetic grade sodium polyaspartate is 500-; the chroma of 20 wt% of cosmetic grade sodium polyaspartate aqueous solution is 50-700 degrees;

in the step A, the temperature of the polymerization reaction is 170-200 ℃, and the time of the polymerization reaction is 2-4 h.

2. The method as claimed in claim 1, wherein the molecular weight of the cosmetic grade sodium polyaspartate is 3000-50000 Da; the conductivity of 1 wt% aqueous solution of cosmetic grade sodium polyaspartate is 700-; the color of the 20 wt% aqueous solution of cosmetic grade sodium polyaspartate solution is 100-500 deg.

3. The method according to claim 1, wherein in step F, the decolorized product is sterilized, and antiseptic components are added and dried to obtain a cosmetic grade sodium polyaspartate.

4. The method according to claim 1, wherein the aspartic acid is L-aspartic acid; the concentration of the phosphoric acid aqueous solution is 70 wt% -85 wt%, and the purity of the citric acid is more than or equal to 99%; in the mixed solution of the phosphoric acid aqueous solution and the citric acid, the mass ratio of the phosphoric acid to the citric acid is (0.2-0.8): 1.

5. The production method according to any one of claims 1 to 4, wherein the pressure of the polymerization reaction is-0.02 to 0.095 MPa.

6. The process according to claim 5, wherein the pressure of the polymerization reaction is from-0.05 to 0.08 MPa.

7. The method of claim 5, wherein the polymerization temperature is subjected to at least 1 gradient decay during the polymerization.

8. The method according to claim 7, wherein the polymerization temperature is gradually decreased from 1 to 2 times during the polymerization; the temperature decay amplitude of the polymerization reaction is 5-20 ℃; the time interval of the temperature decay is 1-2 hours.

9. The production method according to any one of claims 1 to 4, wherein in step B, the polymerization product is pulverized to 40 to 200 mesh; and/or, the alkaline salt comprises sodium carbonate and/or sodium bicarbonate; the mass concentration of the aqueous solution of the alkaline salt is 1-20%.

10. The production method according to claim 9, wherein in step B, the polymerization product is pulverized to 60 to 200 mesh; and/or the mass concentration of the aqueous solution of the alkaline salt is 2-15%.

11. The method according to any one of claims 1 to 4, wherein in step C, the alkali solution is an aqueous solution of sodium hydroxide; the mass concentration of the aqueous solution of the sodium hydroxide is 10-50 percent; the temperature of the hydrolysis reaction is 30-60 ℃; and/or the time of the hydrolysis reaction is 0.5-6 h; and/or the stirring speed during the hydrolysis reaction is 70-120 rpm.

12. The preparation method according to claim 11, wherein in the step C, the mass concentration of the aqueous solution of sodium hydroxide is 20% to 40%; the time of the hydrolysis reaction is 1-2 h.

13. The method according to any one of claims 1 to 4, wherein the separation and purification method of step D comprises a physical separation method and/or a chemical separation method; the physical separation method comprises one or more of filtration, ultrafiltration, nanofiltration, ion exchange and electrodialysis.

14. The method according to claim 13, wherein the separation and purification method in step D is a physical separation method.

15. The production method according to any one of claims 1 to 4, wherein in step E, a decoloring treatment with a decoloring agent is performed; the decolorizing agent comprises one or more of activated carbon, silicon dioxide, aluminum sulfate and PA decolorizing agent; the temperature of the decoloring treatment is 40-70 ℃; the time of the decoloring treatment is 0.5 to 2 hours.

16. The method according to claim 15, wherein the temperature of the decoloring treatment is 50 to 60 ℃ in the step E.

17. The method according to claim 3, wherein the temperature of the sterilization treatment in step F is 80 to 100 ℃, and the time of the sterilization treatment is 20 to 120 min; the antiseptic component comprises one or more of imidazolidinyl urea, methyl paraben, propyl paraben, phenoxyethanol, ethylhexyl glycerol, butanediol, pentanediol, hexanediol, octanediol, p-hydroxyacetophenone and caprylyl hydroximic acid.

18. The method of claim 17, wherein the preservative is used in an amount of 0.1 wt% to 10 wt% based on the total weight of the decolorized product.

19. The method of claim 18, wherein the preservative is used in an amount of 0.1 wt% to 5 wt% based on the total weight of the decolorized product.

20. Use of a cosmetic grade sodium polyaspartate prepared according to the process of any one of claims 1 to 19 in the preparation of skin care, toiletry and color cosmetic products.