Preparation method of toner iron oxide red powder special for cosmetics

Abstract

The invention discloses a preparation method of toner iron oxide red powder special for cosmetics, which comprises the following steps: S1, preparing a ferrous sulfate solution, and carrying out two times of physical clarification and multiple times of recrystallization of filtrate; s2, adding into a strong alkali solution for reaction to obtain an iron oxide slurry product, controlling the primary particle size of iron oxide to be close to a square narrow and lamellar structure, and controlling the particle size dispersion range; s3, plate-frame filter pressing and washing; s4, extruding the filter cake into strips, dispersing into slurry, and grinding; s5, carrying out composite coating operation on the surfaces of the iron oxide particles; s6, after filter pressing, dispersing a filter cake into precursor slurry, and then performing spray drying and crushing; and S7, carrying out destaticizing treatment. According to the preparation method of the iron oxide red powder, the covering power and durability of the liquid foundation are improved, the dark phenomenon in the using process is remarkably reduced, and the requirement of the cosmetic industry for high-performance toner can be met.

Description

Technical Field

[0001] The invention relates to the technical field of special color powder for cosmetics, and in particular to a method for preparing red iron oxide powder of special color powder for cosmetics. Background Art

[0002] Base makeup products, especially liquid foundation, often face a common problem during use: liquid foundation tends to become dull over time. This problem is mainly due to the complex interaction of oils, pigments, fillers and other ingredients in base makeup products. As an indispensable coloring ingredient in base makeup, the stability of pigments is crucial to maintaining the durability of makeup. However, when liquid foundation is applied to the skin, the volatile oil esters in the formula gradually evaporate, causing the pigment particles to agglomerate, making the makeup darker.

[0003] In order to solve this problem, there have been many attempts in the field, but the results are limited. In the prior art, factors such as the amount of color powder added, particle size distribution, compatibility with oils and esters, refractive index, and primary particle size structure all have an important impact on the durability of makeup. Specifically:

[0004] (1) Reduce the amount of color powder added: Reducing the color powder content can reduce its agglomeration in makeup, but it will also affect the coverage of makeup.

[0005] (2) Particle size distribution: The particle size distribution of the pigment needs to be narrow enough to ensure its uniform dispersion in the base makeup, thereby providing maximum coverage.

[0006] (3) Oil and ester compatibility: The compatibility of powder and oil and ester determines the stability of the color powder in the base makeup. Poor compatibility will cause the color powder and oil to separate, accelerating the dullness of the makeup.

[0007] (4) Refractive index: The high refractive index of color powder helps to reduce the color difference before and after oil evaporation and maintain the consistency of makeup.

[0008] (5) Primary particle size structure: Color powder with a flake structure can provide better covering power, but how to maintain the stability of this structure in base makeup remains a challenge.

[0009] The present invention aims to solve the above technical problems through an innovative preparation method, and provide a red iron oxide powder specially used for cosmetics, which can significantly improve the durability and color stability of liquid foundation. Summary of the invention

[0010] In view of the fact that foundation liquid in the prior art is prone to dullness during use, the present invention provides an innovative method for preparing iron oxide red powder, a special color powder for cosmetics, aiming to solve technical problems such as the balance between the amount of color powder added and the covering power, the control of particle size distribution, the compatibility of oils and esters, the optimization of the refractive index, and the stability of the primary particle size structure, thereby significantly improving the durability and color stability of the foundation liquid.

[0011] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0012] A method for preparing red iron oxide powder for cosmetics, the method comprising the following steps:

[0013] S1: using ferrous sulfate as a raw material and dissolving it in deionized water to obtain a ferrous sulfate solution, and then performing two physical clarifications and multiple recrystallizations of the filtrate to control the mass ratio of titanium content to ferrous sulfate to be less than 0.05%;

[0014] S2: adding the ferrous sulfate treated in step S1 to a strong alkaline solution for reaction to obtain an iron oxide slurry product, and strictly controlling the reaction conditions to control the primary particle size of the iron oxide to be close to a square narrow, thin flaky structure, and controlling the particle size of the flaky structure to be dispersed within a specific range;

[0015] S3: subjecting the iron oxide slurry product obtained in step S2 to plate-and-frame filter pressing and then washing with water;

[0016] S4: extruding the filter cake obtained in step S3 into strips, dispersing the strips into a slurry with a certain solid content, and grinding the slurry;

[0017] S5: performing a composite coating operation on the surface of the iron oxide particles using the slurry obtained by sand milling in step S4;

[0018] S6: filtering the slurry obtained in step S5 in a plate-frame filter press, dispersing the obtained filter cake into a precursor slurry with a certain solid content, and then spray drying, and then crushing the powder particles with a jet mill;

[0019] S7: Destaticizing the powder crushed in step S6 to obtain the cosmetic special color powder iron oxide red powder.

[0020] As a preferred technical solution, in step S1, the two physical clarification methods are specifically to first add a flocculant to filter out primary impurities in the ferrous sulfate solution, and then perform a 2000-mesh slurry screen on the filtered filtrate to filter out residual flocculants and impurities thereof.

[0021] As a preferred technical solution, in step S2, the reaction conditions are that the concentration of the strong alkaline solution is 1 to 5 mol / L, the pH value is maintained between 12 and 13 during the reaction, the reaction temperature is controlled at 60 to 80°C, the reaction time is controlled at 0.5 to 2h, and the stirring speed during the reaction is controlled at 200 to 500rpm.

[0022] As a preferred technical solution, the particle size dispersion range of the flaky structure is between 80 and 150 nm, of which the particle size of 100 to 120 nm accounts for more than 80%.

[0023] As a preferred technical solution, in step S4, the solid content of the slurry is 30-40%.

[0024] As a preferred technical solution, in step S5, the specific method of the composite coating operation is: the slurry completed by sand milling in step S4 is heated to 65-75°C, stirred for 20-40 minutes, and after being fully dispersed, vitamin E acetate is first added, stirred for 2-4 hours, the pH is adjusted to 4-4.5, and triethoxyoctylsilane is added, and stirring is continued for 1-3 hours. The present application provides better and wider oil compatibility by composite coating of vitamin E acetate and triethoxyoctylsilane on iron oxide.

[0025] As a preferred technical solution, the added amount of the vitamin E acetate is 0.5-2% of the weight of the iron oxide, and the added amount of triethoxyoctylsilane is 0.1-0.5% of the weight of the iron oxide.

[0026] As a preferred technical solution, in step S6, the solid content of the precursor slurry is 30-40%.

[0027] As a preferred technical solution, the salt content of the iron oxide powder itself is controlled so that the sodium content is less than 100 ppm, the sulfur content is less than 100 ppm, and the conductivity is less than 100 us / cm.

[0028] Another aspect of the present invention is to provide a method for preparing red iron oxide powder, a color powder for cosmetics. The red iron oxide powder is prepared by the method for preparing red iron oxide powder, a color powder for cosmetics.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The preparation method of the special color powder iron oxide red powder of the cosmetics of the present invention, through a series of innovative steps, including but not limited to physical clarification of ferrous sulfate solution, recrystallization, precise reaction control in strong alkaline solution, plate and frame filter pressing water washing, filter cake extrusion grinding, composite coating operation, spray drying, crushing and destaticization treatment, not only achieves high purity and precise particle size control of iron oxide red powder, but also achieves excellent compatibility and emulsification stability with oil esters in cosmetic formulas. This design not only enhances the covering power and durability of liquid foundation, but also maintains the stability of cosmetic color, which helps to significantly reduce the dull phenomenon of liquid foundation during use. In addition, the present invention optimizes its dispersibility in cosmetics by accurately controlling the particle size, salt content and composite coating process of iron oxide red powder, and improves the overall performance of cosmetics and the user experience. DETAILED DESCRIPTION

[0031] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0032] Example 1

[0033] The method for preparing the iron oxide red powder for cosmetics in this embodiment comprises the following steps:

[0034] S1: Use ferrous sulfate as a raw material and dissolve it in deionized water to obtain a ferrous sulfate solution with a mass concentration of 30%, and then perform two physical clarifications and multiple recrystallizations of the filtrate (the filtrate is crystallized by ice water circulation), and control the mass ratio of titanium content to ferrous sulfate to be less than 0.05%; the two physical clarification methods are specifically to first add flocculant polyacrylamide to filter out primary impurities in the ferrous sulfate solution, and then perform a 2000-mesh slurry screen on the filtered filtrate to filter out residual flocculant and its impurities.

[0035] S2: Add the ferrous sulfate treated in step S1 to a sodium hydroxide solution for reaction to obtain an iron oxide slurry product, and strictly control the reaction conditions to control the primary particle size of the iron oxide to be close to a square narrow, thin flaky structure, and control the particle size of the flaky structure to be dispersed between 80 and 150 nm, wherein the particle size of 100 to 120 nm accounts for more than 80%. The reaction conditions are a strong alkaline solution concentration of 1 mol / L, a pH value of 12 during the reaction, a reaction temperature of 60°C, a reaction time of 1 h, and a stirring speed of 300 rpm during the reaction.

[0036] S3: The iron oxide slurry product obtained in step S2 is subjected to plate and frame filter pressing and then washed with 10 times the amount of water;

[0037] S4: extruding the filter cake obtained in step S3 into strips, dispersing the strips into a slurry with a solid content of 40%, and grinding the slurry;

[0038] S5: The slurry obtained by sand milling in step S4 is subjected to a composite coating operation on the surface of the iron oxide particles; the specific method of the composite coating operation is: the slurry obtained by sand milling in step S4 is heated to 65°C, stirred for 20 minutes, and after being fully dispersed, vitamin E acetate is first added, stirred for 3 hours, the pH is adjusted to 4, and triethoxyoctylsilane is added, and stirring is continued for 2 hours. The amount of vitamin E acetate added is 1% of the weight of the iron oxide, and the amount of triethoxyoctylsilane added is 0.1% of the weight of the iron oxide.

[0039] S6: The slurry obtained in step S5 is filtered in a plate-frame filter press, and the obtained filter cake is dispersed into a precursor slurry with a solid content of 30%, and then spray-dried, and the powder particles are crushed by a jet mill.

[0040] S7: Destaticize the powder crushed in step S6, specifically, use an electric absorber to absorb the six sides of the powder to obtain the cosmetic special color powder iron oxide red powder. The salt content of the iron oxide powder itself is controlled, the sodium content is less than 100ppm, the sulfur content is less than 100ppm, and the conductivity is less than 100us / cm.

[0041] Example 2

[0042] The method for preparing the iron oxide red powder for cosmetics in this embodiment comprises the following steps:

[0043] S1: Use ferrous sulfate as a raw material and dissolve it in deionized water to obtain a ferrous sulfate solution with a mass concentration of 32%, and then perform two physical clarifications and multiple recrystallizations of the filtrate (the filtrate is crystallized by ice water circulation), and control the mass ratio of titanium content to ferrous sulfate to be less than 0.05%; the method of the two physical clarifications is specifically to first add a flocculant polyacrylamide to filter out primary impurities in the ferrous sulfate solution, and then perform a 2000-mesh slurry screen on the filtered filtrate to filter out residual flocculants and impurities thereof.

[0044] S2: Add the ferrous sulfate treated in step S1 to a sodium hydroxide solution for reaction to obtain an iron oxide slurry product, and strictly control the reaction conditions to control the primary particle size of the iron oxide to be close to a square narrow, thin flaky structure, and control the particle size of the flaky structure to be dispersed between 80 and 150 nm, wherein the particle size of 100 to 120 nm accounts for more than 80%. The reaction conditions are a strong alkaline solution concentration of 3 mol / L, a pH value maintained at 13 during the reaction, a reaction temperature controlled at 70°C, a reaction time controlled at 1.5 h, and a stirring speed controlled at 200 rpm during the reaction.

[0045] S3: The iron oxide slurry product obtained in step S2 is subjected to plate and frame filter pressing and then washed with 10 times the amount of water;

[0046] S4: extruding the filter cake obtained in step S3 into strips, dispersing the strips into a slurry with a solid content of 35%, and grinding the slurry;

[0047] S5: The slurry obtained by sand milling in step S4 is subjected to a composite coating operation on the surface of the iron oxide particles; the specific method of the composite coating operation is: the slurry obtained by sand milling in step S4 is heated to 75°C, stirred for 40 minutes, and after being fully dispersed, vitamin E acetate is first added, stirred for 2 hours, the pH is adjusted to 4.5, and triethoxyoctylsilane is added, and stirring is continued for 3 hours. The amount of vitamin E acetate added is 2% of the weight of the iron oxide, and the amount of triethoxyoctylsilane added is 0.5% of the weight of the iron oxide.

[0048] S6: The slurry obtained in step S5 is filtered in a plate-frame filter press, and the obtained filter cake is dispersed into a precursor slurry with a solid content of 35%, and then spray-dried, and the powder particles are crushed by a jet mill.

[0049] S7: Destaticize the powder crushed in step S6, specifically, use an electric absorber to absorb the six sides of the powder to obtain the cosmetic special color powder iron oxide red powder. The salt content of the iron oxide powder itself is controlled, the sodium content is less than 100ppm, the sulfur content is less than 100ppm, and the conductivity is less than 100us / cm.

[0050] Example 3

[0051] The method for preparing the iron oxide red powder for cosmetics in this embodiment comprises the following steps:

[0052] S1: Use ferrous sulfate as a raw material and dissolve it in deionized water to obtain a ferrous sulfate solution with a mass concentration of 35%, then perform two physical clarifications and multiple recrystallizations of the filtrate (the filtrate is crystallized by ice water circulation), and control the mass ratio of titanium content to ferrous sulfate to be less than 0.05%; the two physical clarification methods are specifically to first add flocculant polyacrylamide to filter out primary impurities in the ferrous sulfate solution, and then perform a 2000-mesh slurry screen on the filtered filtrate to filter out residual flocculant and its impurities.

[0053] S2: Add the ferrous sulfate treated in step S1 to a sodium hydroxide solution for reaction to obtain an iron oxide slurry product, and strictly control the reaction conditions to control the primary particle size of the iron oxide to be close to a square narrow, thin flaky structure, and control the particle size of the flaky structure to be dispersed between 80 and 150 nm, wherein the particle size of 100 to 120 nm accounts for more than 80%. The reaction conditions are a concentration of a strong alkaline solution of 5 mol / L, a pH value maintained between 13 during the reaction, a reaction temperature controlled at 80°C, a reaction time controlled at 2 hours, and a stirring speed controlled at 500 rpm during the reaction.

[0054] S3: The iron oxide slurry product obtained in step S2 is subjected to plate and frame filter pressing and then washed with 10 times the amount of water;

[0055] S4: extruding the filter cake obtained in step S3 into strips, dispersing the strips into a slurry with a solid content of 30%, and grinding the slurry;

[0056] S5: The slurry obtained by sand milling in step S4 is subjected to a composite coating operation on the surface of the iron oxide particles; the specific method of the composite coating operation is: the slurry obtained by sand milling in step S4 is heated to 65°C, stirred for 40 minutes, and after being fully dispersed, vitamin E acetate is first added, stirred for 4 hours, the pH is adjusted to 4, and triethoxyoctylsilane is added, and stirring is continued for 1 hour. The amount of vitamin E acetate added is 1% of the weight of the iron oxide, and the amount of triethoxyoctylsilane added is 0.3% of the weight of the iron oxide.

[0057] S6: The slurry obtained in step S5 is filtered in a plate-frame filter press, and the obtained filter cake is dispersed into a precursor slurry with a solid content of 40%, and then spray-dried, and the powder particles are crushed by a jet mill.

[0058] S7: Destaticize the powder crushed in step S6, specifically, use an electric absorber to absorb the six sides of the powder to obtain the cosmetic special color powder iron oxide red powder. The salt content of the iron oxide powder itself is controlled, the sodium content is less than 100ppm, the sulfur content is less than 100ppm, and the conductivity is less than 100us / cm.

[0059] Comparative Example 1

[0060] The preparation method of the iron oxide red powder for cosmetic color powder in this comparative example has the same steps as those in Example 1, except that in step S2, the reaction condition is that the concentration of the strong alkaline solution is 0.5 mol / L, the pH value is maintained at 10 during the reaction, the reaction temperature is controlled at 50°C, the reaction time is controlled at 1h, and the stirring speed during the reaction is controlled at 300rpm.

[0061] Comparative Example 2

[0062] The preparation method of the iron oxide red powder for cosmetic color powder in this comparative example has the same steps as those in Example 1, except that in step S5, vitamin E acetate is not added for coating in the composite coating operation, and only triethoxyoctylsilane is added for coating.

[0063] The performance test was performed on the samples of the iron oxide red powder prepared in Examples 1 to 3 and Comparative Examples 1 to 2 for special cosmetic color powders. Specifically, 8 wt% of the iron oxide powder sample was mixed with other 92 wt% of cosmetic ingredients (5% olive oil, 3% jojoba oil, 2% isodecyl isononanoate, 2% polysorbate, 1% parabens, 0.5% vitamin E, 0.2% carbomer, 0.1% xanthan gum, 0.2% sodium hyaluronate, appropriate amount of citric acid to adjust the pH value to 6.5, and the balance was deionized water) to prepare a simulated foundation liquid; the performance results are shown in Table 1:

[0064] The covering power test method is as follows: the color difference meter is used to measure the skin color change before and after applying the simulated liquid foundation (measured immediately after application and after a 30-minute interval) to evaluate the covering effect of the color powder. The ΔE value represents the total color difference of the skin color change before and after applying the simulated liquid foundation measured by the color difference meter. The smaller the ΔE value, the better the covering power.

[0065] Persistence test method: Persistence is tested by applying cosmetics on the skin of volunteers and evaluating the change in covering power after 8 hours. The smaller the ΔE value, the better the persistence.

[0066] Oil and ester compatibility test method: The compatibility of the color powder and the oil and ester mixture is evaluated by centrifugal test. The centrifugal speed is set to 2000rpm and the centrifugal time is 1h. It is evaluated whether the color powder will separate under the action of centrifugal force.

[0067] Color stability test method: Use accelerated aging test (test conditions are UV lamp, light intensity 1.5W / m 2 , test time 168h, test temperature 50℃) to simulate the color change during long-term use. The smaller the ΔE value, the better the color stability. Table 1 project Implementation 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Hiding power, ΔE 3.5 3.7 3.6 4.1 4.2 Persistence, ΔE <1 <1 <1 1.5 1.7 Oil and ester compatibility No separation No separation No separation Slight separation Clear separation Color stability, ΔE <1 <1 <1 2 3

[0068] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention, and these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A method for preparing red iron oxide powder for cosmetics, characterized in that: The preparation method comprises the following steps: S1: using ferrous sulfate as a raw material and dissolving it in deionized water to obtain a ferrous sulfate solution, and then performing two physical clarifications and multiple recrystallizations of the filtrate to control the mass ratio of titanium content to ferrous sulfate to be less than 0.05%; S2: adding the ferrous sulfate treated in step S1 to a strong alkaline solution for reaction to obtain an iron oxide slurry product, and strictly controlling the reaction conditions to control the primary particle size of the iron oxide to be close to a square narrow, thin flaky structure, and controlling the particle size of the flaky structure to be dispersed within a specific range; S3: subjecting the iron oxide slurry product obtained in step S2 to plate-and-frame filter pressing and then washing with water; S4: extruding the filter cake obtained in step S3 into strips, dispersing the strips into a slurry with a certain solid content, and grinding the slurry; S5: performing a composite coating operation on the surface of the iron oxide particles using the slurry obtained by sand milling in step S4; S6: filtering the slurry obtained in step S5 in a plate-frame filter press, dispersing the obtained filter cake into a precursor slurry with a certain solid content, and then spray drying, and then crushing the powder particles with a jet mill; S7: Destaticizing the powder crushed in step S6 to obtain the cosmetic special color powder iron oxide red powder.

2. The method for preparing the iron oxide red powder for cosmetics as claimed in claim 1, characterized in that: In step S1, the two physical clarification methods specifically include first adding a flocculant to filter out primary impurities in the ferrous sulfate solution, and then performing a 2000-mesh slurry screen on the filtered filtrate to filter out residual flocculants and impurities thereof.

3. The method for preparing the iron oxide red powder for cosmetics as claimed in claim 1, characterized in that: In step S2, the reaction conditions are that the concentration of the strong alkaline solution is 1-5 mol / L, the pH value is maintained between 12-13 during the reaction, the reaction temperature is controlled at 60-80°C, the reaction time is controlled at 0.5-2h, and the stirring speed during the reaction is controlled at 200-500rpm.

4. The method for preparing the red iron oxide powder for cosmetics as claimed in claim 1, characterized in that: The particle size dispersion range of the flaky structure is between 80 and 150 nm, of which the particle size of 100 to 120 nm accounts for more than 80%.

5. The method for preparing the iron oxide red powder for cosmetics as claimed in claim 1, characterized in that: In step S4, the solid content of the slurry is 30-40%.

6. The method for preparing the red iron oxide powder for cosmetics as claimed in claim 1, characterized in that: In step S5, the specific method of the composite coating operation is: the slurry completed by sand milling in step S4 is heated to 65-75°C, stirred for 20-40 minutes, and after being fully dispersed, vitamin E acetate is first added, stirred for 2-4 hours, the pH is adjusted to 4-4.5, and triethoxyoctylsilane is added, and stirring is continued for 1-3 hours.

7. The method for preparing the red iron oxide powder for cosmetics as claimed in claim 6, characterized in that: The added amount of the vitamin E acetate is 0.5-2% of the weight of the iron oxide, and the added amount of the triethoxyoctylsilane is 0.1-0.5% of the weight of the iron oxide.

8. The method for preparing the iron oxide red powder for cosmetics as claimed in claim 1, characterized in that: In step S6, the solid content of the precursor slurry is 30-40%.

9. The method for preparing the iron oxide red powder for cosmetics as claimed in claim 1, characterized in that: The salt content of the iron oxide powder itself is controlled to be less than 100 ppm for sodium, less than 100 ppm for sulfur, and less than 100 us / cm for conductivity.

10. A method for preparing red iron oxide powder for cosmetics, characterized in that: The red iron oxide powder is prepared by the method for preparing the red iron oxide powder for cosmetics as claimed in any one of claims 1 to 9.