Pigment composition for dyeing hair, blackening hair and nourishing hair, and use thereof

Abstract

The present application belongs to the technical field of cosmetics, and particularly relates to a pigment composition for dyeing hair, blackening hair and nourishing hair and the use thereof. The pigment composition provided by the present application comprises: a) pigments derived from plant sources, comprising catechins, anthocyanins, procyanidins, and plant extracts containing pigment components; b) a simulated melanin precursor, comprising 5,6-dihydroxyindole or 5,6-dihydroxyindoline; c) one or more peroxides; and d) an organic compound which is misible or insoluble with water. The pigment composition provided by the present application is free of components such as phenylenediamines, derivatives thereof and hydrogen peroxide, and therefore does not cause allergies.

Description

Pigment composition for dyeing, darkening and nourishing hair and its application

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on July 25, 2023, with application number CN202310913878.3 and invention name “A pigment composition for dyeing, blackening and nourishing hair and its application”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application belongs to the technical field of cosmetics, and specifically relates to a pigment composition for dyeing, darkening and nourishing hair and its application. Background Art

[0003] Hair dye is a common cosmetic product and a necessity for anyone who wants to change their hair color. Worldwide, hair dyeing is becoming increasingly important, with the number of people using hair dye at hair salons, at hair salons, and at home increasing rapidly. However, the properties of the chemical dyes in hair dyes pose potential health risks to users. Most hair dyes currently on the market use paraphenylenediamine (PPD) or PPD derivatives as their primary ingredient. PPD itself is highly allergenic and can cause cross-sensitivity with a variety of substances, such as azobenzenes, anilines, local anesthetics (procaine, benzocaine), and sulfonamides. PPD is also easily absorbed through the skin, causing gastrointestinal and nervous system damage, renal failure, teratogenicity, carcinogenesis, and immune system impairment. Furthermore, PPD-based hair dyes are oxidative dyes, and the hydrogen peroxide treatment destroys the original proteins and amino acids. Dyed hair can become dry, lose its luster and elasticity, and cause irreversible damage to the hair. Therefore, developing non-toxic, non-carcinogenic, and hair-protecting hair dye alternatives and hair dye application methods can minimize potential harm to human health.

[0004] Several plant anthocyanin-based dyes have been patented or marketed. For example, JPH04119179A discloses a specific anthocyanin compound, cyanidin 3-arachidanoside, in combination with quercetin glucuronide for dyeing wool. This patent relates to the dyeing of fibers, particularly silk and wool, and requires a pH of 2.5 combined with a temperature of 95°C for one hour, making it completely unsuitable for hair dyeing. While suggesting its use as a dye, the patent does not mention its application on hair, or indeed its use in any cosmetic applications.

[0005] Chinese Patent Publication No. CN 101164528A uses the plant pigment catechu as a melanin precursor. Under the action of ferrous salts, it forms a complex on the hair to form a black color, achieving the purpose of blackening. Chinese Patent Publication No. CN 1923164A also uses the same principle, combining polyphenols in pomegranate peel with metal chelators to form a brown complex. U.S. Patent No. 4801302 discloses a hair dyeing method using sappan wood and copper salt hair dye. While the hair dyes mentioned in these patents do not have the harmful effects on the scalp caused by substances such as p-phenylenediamine and hydroquinone, they also have significant drawbacks. The first is that the adsorption is not strong. Even if the polyphenols form a complex during the chelation process with metal ions, the complex only adheres to the hair surface and does not have a strong adsorption effect on the hair, making it very easy to fade.

[0006] Furthermore, existing hair dyes still suffer from the drawbacks of plant-based hair dyes during the actual dyeing process. A single application of a mixture of various reagents is difficult to achieve the desired effect, so all of them require two, three, or even more applications and washes, resulting in a complex dyeing process. Dyeing can take up to 2.5 hours or longer, and they suffer from poor permeability and are prone to fading. Most are semi-permanent hair dyes. These issues directly impact the dyeing effect, leading to low consumer acceptance.

[0007] Summary of the Invention

[0008] The present application provides a hair-blackening and nourishing composition and method for use thereof, which contains a pigment as a functional ingredient, does not contain aniline, hydrogen peroxide, and other ingredients, and is safe, non-irritating, non-allergenic, and has no pungent odor. The composition is simple and convenient to use, and after use, the color is fast and natural. The composition not only has the function of blackening hair, but also has the function of nourishing hair.

[0009] The present application provides a pigment composition for dyeing, darkening, and nourishing hair, the pigment composition comprising:

[0010] a) Pigments obtained from plant sources: including at least one of the following groups: catechins, anthocyanins, proanthocyanidins, plant extracts containing catechins, anthocyanins and / or proanthocyanidins;

[0011] b) Simulated melanin precursors: including 5,6-dihydroxyindole, 5,6-dihydroxyindoline, and polymers thereof or with each other;

[0012] c) one or more metal peroxides;

[0013] d) an inorganic or organic compound that is miscible or insoluble in water in an amount of 5 wt.% to 60 wt.%, with a pH range of 7 to 12, preferably 8 to 10.

[0014] In the present application, the pigments obtained from plant sources are derived from specific plants and fruits, in particular black wolfberry, black currant, blackberry, blueberry, lingonberry, cranberry, grape, chokeberry, Saskatoon berry, sea buckthorn, mulberry, cherry, cocoa, acerola, prickly pear, red cabbage and fig, or fig juice or squeezed juice and its application in the formulation of permanent dye for human hair.

[0015] Furthermore, the pigment obtained from plant sources includes the following components in parts by weight: 3 to 8 parts of black wolfberry extract, 2 to 5 parts of blackcurrant extract, 1 to 4 parts of blackberry extract, 2 to 6 parts of blueberry extract, 1 to 3 parts of bilberry extract, 1 to 4 parts of cranberry extract, 1 to 5 parts of mulberry extract, 1 to 3 parts of cocoa seed extract, 2 to 5 parts of goldenrod fruit extract and 1 to 4 parts of roxburghii fruit extract.

[0016] The present application is compounded with a variety of plant extracts, which are rich in catechins, anthocyanins, proanthocyanidins and their oxidative polymerization products. The components produce a synergistic effect, resulting in a good hair dyeing effect, and the remaining nutrients in the extracts also have a hair nourishing effect.

[0017] The content of catechins, anthocyanins, proanthocyanidins and / or their oxidative polymerization products and plant extracts containing the above components is 1 wt.% to 20 wt.%.

[0018] In a specific embodiment, the weight percentage of catechins, anthocyanins, proanthocyanidins and / or their oxidative polymerization products and plant extracts containing the above ingredients can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%.

[0019] The catechin class of compounds includes, but is not limited to, catechin (C), epicatechin (EC), gallocatechin (GC), epigallocatechin (EGC), catechin gallate (CG), epicatechin gallate (ECG), gallocatechin gallate (GCG), and epigallocatechin gallate (EGCG).

[0020] The chemical structures of catechin and the four main catechin-like compounds are shown below:

[0021] Anthocyanins include but are not limited to 6 non-glycosides: Pelargonidin, Cyanidin, Delphinidin, Peonidin, Petunidin and Malvidin. The skeleton structure of anthocyanins is shown below:

[0022] The simulated melanin precursor includes 5,6-dihydroxyindole, 5,6-dihydroxyindoline and polymers thereof, and the molecular formula is as follows:

[0023] 5,6-dihydroxyindole;

[0024] 5,6-dihydroxyindoline;

[0025] Polydihydroxyindole;

[0026] The polymers mentioned above, either individually or mutually, specifically refer to polydihydroxyindole and melanin, and their content is 0.5 wt.% to 10 wt.%.

[0027] In specific embodiments, the weight percentage of the simulated melanin precursor can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%.

[0028] Furthermore, the simulated melanin precursor comprises 5,6-dihydroxyindole, 5,6-dihydroxyindoline and polydihydroxyindole in a weight ratio of 2 to 5:2 to 5:1.

[0029] This application adds a simulated melanin precursor, and the melanin converted is similar in structure to the melanin of human hair, has good affinity, natural color, and can protect hair while dyeing. However, it was found that the color of bleached long curly hair was easily uneven when dyed with this composition. By adding 5,6-dihydroxyindole, 5,6-dihydroxyindoline and polydihydroxyindole in a weight ratio of 2 to 5:2 to 5:1, the resulting composition has excellent dyeing effect on bleached long curly hair. It is speculated that under this ratio, after the three simulated melanin precursors penetrate into the hair during the hair dyeing process, they oxidize and polymerize with each other, and the colored macromolecular substance formed has a more complex structure and is easier to be fixed and colored.

[0030] The one or more peroxides include metal peroxides, peroxy acid salts and organic peroxides.

[0031] Furthermore, the peroxide is a metal peroxide, more preferably comprising one or more of sodium peroxide, potassium peroxide, calcium peroxide, magnesium peroxide, zinc peroxide, potassium persulfate and strontium peroxide.

[0032] The peroxide content is 1 wt.% to 10 wt.%.

[0033] In specific embodiments, the weight percentage of peroxide can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%.

[0034] The water-miscible or insoluble inorganic or organic compound is selected from one or more of surfactants, organic thickeners, inorganic thickeners, antioxidants, chelating agents, fragrances, buffers, dispersants, conditioners, film-forming agents, ceramide preservatives, and sunscreens, and its content is 5 wt.% to 60 wt.%.

[0035] In specific embodiments, the weight percentage of inorganic and organic compounds that are miscible or insoluble in water is 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%.

[0036] The thickener includes, but is not limited to, sodium chloride, potassium chloride, ammonium chloride, monoethanolamine chloride, diethanolamine chloride, sodium sulfate, sodium phosphate, polyurethane thickener, modified polyurea thickener, and modified polyether thickener.

[0037] The surfactant is selected from one or more of sodium fatty acid methyl ester ethoxylate sulfonate, decyl sulfobetaine, and sodium lauroamphoacetate.

[0038] The surfactant is preferably sodium fatty acid methyl ester ethoxylate sulfonate, decyl sulfobetaine, and sodium lauroamphoacetate in a weight ratio of 0.3 to 0.9:1:1 to 5.

[0039] Since the system of the present application contains complex plant extracts and simulated melanin precursors, both lipophilic and hydrophilic components are present in the system, resulting in poor stability of the system. By compounding the three surfactants, the problem of stability of the composition at room temperature can be well solved. However, the stability of the composition at high or low temperatures is not ideal. After adjusting the formula many times, it was found that the surfactant compounded with sodium fatty acid methyl ester ethoxylate sulfonate, decyl sulfobetaine, and sodium lauroylamphoacetate in a weight ratio of 0.3 to 0.9:1:1 to 5 was used. The composition achieved the best stability at high temperature, low temperature, and variable temperature. It is speculated that the compounding of these three components in the system of the present application has a synergistic effect, which can better regulate the compatibility of the plant extract and the simulated melanin precursor, reduce the oil-water interfacial tension to an ultra-low level, stabilize the oil-water interface, and also find that the surfactant can promote the oxidative polymerization of the simulated melanin precursor into melanin, thereby shortening the hair dyeing time.

[0040] The dosage form of the composition is one of ointment, emulsion, powder and liquid shampoo.

[0041] The present application provides a mixture of catechins, anthocyanidins, proanthocyanidins and / or oxidative polymerization products thereof, and these mixtures are obtained by conventional extraction, separation, purification and concentration techniques and are derived from specific plant sources.

[0042] Another aspect of the present application provides a dosage form and method of use of the pigment composition in black hair and hair care, including:

[0043] a) Compositions include powders and emulsions.

[0044] b) The usage process is as follows: apply combination 1 (powder + emulsion) evenly on the hair, keep it on for 30 to 60 minutes, rinse, and then apply combination 2 (powder + emulsion) on the hair in the same way as above, keep it on for 5 to 30 minutes, and rinse. The colorant will be adsorbed onto the human keratin. Beneficial effects:

[0045] This application uses plant-derived pigments as colorants for dyeing black hair. It does not contain ingredients such as phenylenediamine and its derivatives, hydrogen peroxide, etc., is non-allergenic, and has no irritating odor. The formula uses catechins and anthocyanins to compound the color. It not only dyes the hair black, but also nourishes the hair. After use, the color is fast and natural.

[0046] The hair dyeing composition of the present application has the advantages of uniform hair dyeing, little damage to hair, good touch feeling of hair after dyeing and long-lasting effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] FIG1 is a close-up photo of hair before and after dyeing using the composition of Example 1;

[0048] FIG2 is a close-up photo of hair before and after using the composition of Example 1;

[0049] FIG3 is a close-up photo of the hair before and after using the composition of Example 1 for hair care. DETAILED DESCRIPTION

[0050] The present invention is further described below with reference to the following examples. These examples are merely typical descriptions of the present invention, but the present invention is not limited thereto. The experimental methods used in the following examples are conventional methods unless otherwise specified, and the raw materials and reagents used are all commercially available from conventional markets unless otherwise specified.

[0051] Example 1 Hair dye composition

[0052] The hair dyeing composition comprises the following components:

[0053] a) Pigments obtained from plant sources: including catechins, anthocyanins, proanthocyanidins and / or oxidative polymerization products thereof, and plant extracts containing the above ingredients, with a content of 14 wt.%; specifically, the pigments obtained from plant sources include the following components in parts by weight: 5 parts of black wolfberry extract, 3 parts of blackcurrant extract, 2 parts of blackberry extract, 4 parts of blueberry extract, 1 part of bilberry extract, 3 parts of cranberry extract, 4 parts of mulberry extract, 1 part of cocoa seed extract, 3 parts of malvaceae fruit extract, and 2 parts of roxburghii fruit extract.

[0054] b) Simulated melanin precursor: comprising 5,6-dihydroxyindole, 5,6-dihydroxyindoline, and polymers thereof, each or both, at a content of 5 wt.%; specifically, the simulated melanin precursor comprises 5,6-dihydroxyindole, 5,6-dihydroxyindoline, and polydihydroxyindole in a weight ratio of 4:3:1. 5,6-dihydroxyindole was purchased from Aladdin, D183610; 5,6-dihydroxyindoline was purchased from Hubei Jianchu Biopharmaceutical Co., Ltd.; and polydihydroxyindole was purchased from Shanghai Future Industrial Co., Ltd.

[0055] c) strontium peroxide, in an amount of 3 wt.%;

[0056] d) Surfactant: sodium fatty acid methyl ester ethoxylate sulfonate, decyl sulfobetaine, and sodium lauroamphoacetate in a weight ratio of 0.5:1:3. The surfactant content was 22 wt.%, the pH was 8.5, and the balance was water. Sodium fatty acid methyl ester ethoxylate sulfonate was purchased from Jinan Yeqing Biotechnology Co., Ltd.; decyl sulfobetaine was purchased from Shanghai Yuanye Biotechnology Co., Ltd.; and sodium lauroamphoacetate was purchased from Wuhan Huaxiang Kejie Biotechnology Co., Ltd.

[0057] Comparative Example 1

[0058] The difference between this comparative example and Example 1 is that the hair dyeing composition includes the following components:

[0059] a) catechins, anthocyanins, proanthocyanidins and / or their oxidative polymerization products, and plant extracts containing the above ingredients, with a content of 11 wt.%;

[0060] b) 5,6-dihydroxyindole, 5,6-dihydroxyindoline and polymers thereof, in an amount of 2 wt.%;

[0061] c) Strontium peroxide, content of 7 wt.%.

[0062] Comparative Example 2

[0063] The difference between this comparative example and Example 1 is that the hair dyeing composition includes the following components:

[0064] a) catechins, anthocyanins, proanthocyanidins and / or their oxidative polymerization products, and plant extracts containing the above ingredients, with a content of 25 wt.%;

[0065] b) 5,6-dihydroxyindole, 5,6-dihydroxyindoline and polymers thereof, in an amount of 17 wt.%;

[0066] d) The surfactant is sodium fatty acid methyl ester ethoxylate sulfonate, decyl sulfobetaine, and sodium lauroamphoacetate in a weight ratio of 0.5:1:3. The content of the surfactant is 22 wt.%, the pH is 8.5, and the balance is water.

[0067] Comparative Example 3

[0068] The difference between this comparative example and Example 1 is that the surfactants are glyceryl monostearate, sodium dodecylbenzenesulfonate, and sodium lauroamphoacetate in a weight ratio of 2:3:1, all of which were purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0069] Comparative Example 4

[0070] The difference between this comparative example and Example 1 is that the simulated melanin precursor is 5,6-dihydroxyindole.

[0071] Comparative Example 5

[0072] Commercially available hair dye: Schwarzkopf, model: Yiran hair dye combination, color: black.

[0073] Example 2: Using indicator statistics

[0074] 1. Hair samples were dyed using the hair dye compositions of Example 1 and Comparative Examples 1-5. The application process was as follows: the composition was evenly applied to the hair and left on for 40 minutes. If the temperature was below 20°C, an additional 10 minutes was required. The hair was then rinsed. The hair was then evenly applied to the hair using the same method as above. The hair was left on for 15 minutes, then rinsed and shampooed to remove any loose color. If necessary, the hair was rinsed twice. Commercially available hair dyes were used according to their instructions. The indices after application of the hair dyes were statistically analyzed.

[0075] The results are shown in Table 1 below:

[0076] Table 1 Statistical results of indicators

[0077] Sensory evaluation: Place a small amount of dyed hair sample in a standard white light box. Observe the color of the sample with the naked eye and compare it with the standard color palette. Name the colors that are the same or similar to the standard color palette and rate them: 3 - consistent with the standard color, 2 - close to the color with slight deviation, 1 - significant deviation, 0 - almost no color.

[0078] Feel evaluation: Gently pinch the hair with your index finger and thumb, and slide it gently from the root to the end of the hair, feeling the smoothness and moisturization of the hair, and rate it: 0-excellent, 1-good, 2-average, 3-very poor.

[0079] Hair dyeing performance evaluation: After dyeing according to the method described in Example 2, rinse with water immediately, treat with shampoo and conditioner, and then dry. Visual evaluation: 3-full color, 2-somewhat underdone color, 1-little color, underdone, 0-no color.

[0080] Durability evaluation: The dyed hair sample was placed at room temperature for three months, rinsed with water, and then dried. Visual evaluation was performed: 3 - close to the original color, with little change; 2 - slightly lighter in color; 1 - significantly lighter in color; 0 - dyed hair color has basically disappeared.

[0081] As can be seen from the above table, the composition of the present application has significantly improved sensory, feel, hair dyeing performance, and durability compared to the compositions of Comparative Examples 1 to 5, and has the advantages of uniform hair dyeing, less damage to hair, good touch of hair after dyeing, and long-lasting effect.

[0082] 2. Stability test

[0083] The compositions of the examples and comparative examples of this application were sealed and placed in 15°C, 5°C, and 40°C environments for one month and ten cycles. The appearance of the products was observed, with one cycle consisting of 24 hours at each of 15°C and 40°C. The results are shown in Table 2 below.

[0084] Table 2 Stability test results

[0085] Example 3: Performance test

[0086] The hair dye composition described in Example 1 was used to test the hair dyeing, hair nourishing and hair care performance of the experimenters using the same method as Example 2. The results are shown in Figures 1 to 3.

[0087] As can be seen in Figure 1, after using the composition of this application to dye hair, the hair color of the subjects showed a significant improvement. Before use, the hair was gray and dull; after use, the hair was black, shiny, and full of color. The color was also evenly dyed.

[0088] As can be seen from FIG2 , after using the composition of the present application for hair care, the hair becomes smoother and has a darker color than before use.

[0089] As can be seen from Figure 3, after using the composition of the present application to nourish hair, dry, frizzy and split hair are significantly reduced, and the hair is smoother and more lustrous.

[0090] Therefore, the composition of the present application can dye hair to a natural color after use, and has good hair nourishing and hair care effects, and has good application prospects.

[0091] The above describes the specific embodiments of the present application. It should be understood that the present application is not limited to the above specific embodiments, and those skilled in the art may make various variations or modifications within the scope of the claims, which do not affect the substantive content of the present application.

Claims

1. A pigment composition for hair dyeing, hair darkening and hair nourishing, characterized in that: The material components of the pigment composition are as follows: a) a pigment obtained from a plant source: including at least one of the following groups: catechins, anthocyanins, proanthocyanidins, plant extracts containing pigment components of catechins, anthocyanins and / or proanthocyanidins; b) Simulated melanin precursors: including 5,6-dihydroxyindole and 5,6-dihydroxyindoline; c) one or more peroxides, including metal peroxides, peroxy acid salts and organic peroxides; d) an inorganic or organic compound that is miscible or insoluble in water; the inorganic or organic compound comprises one or more of a surfactant, an organic thickener, an inorganic thickener, an antioxidant, a chelating agent, a fragrance, a buffer, a dispersant, a conditioner, a film former, a ceramide preservative and a sunscreen, and the pH value is 7 to 12; e) The balance is water.

2. The pigment composition according to claim 1, characterized in that The plant extracts include extracts of one or more of black wolfberry, black currant, blackberry, blueberry, lingonberry, cranberry, grape, chokeberry, saskatoon berry, sea buckthorn, mulberry, cherry, cocoa, acerola, prickly pear, red cabbage and fig.

3. The pigment composition according to claim 1 or 2, characterized in that The pigment obtained from plant sources includes the following components in parts by weight: 3-8 parts of black wolfberry extract, 2-5 parts of blackcurrant extract, 1-4 parts of blackberry extract, 2-6 parts of blueberry extract, 1-3 parts of bilberry extract, 1-4 parts of cranberry extract, 1-5 parts of mulberry extract, 1-3 parts of cocoa seed extract, 2-5 parts of goldenseal fruit extract and 1-4 parts of roxburghii fruit extract.

4. The pigment composition according to claim 1 or 2, characterized in that In the pigment composition, the content of the pigment obtained from plant sources is 1 wt.% to 20 wt.%.

5. The pigment composition according to claim 1, characterized in that In the pigment composition, the content of the simulated melanin precursor is 0.5wt.% to 10wt.%.

6. The pigment composition according to claim 1, characterized in that The simulated melanin precursor further comprises a polymer; the monomer of the polymer is 5,6-dihydroxyindole and / or 5,6-dihydroxyindoline.

7. The pigment composition according to claim 6, characterized in that The simulated melanin precursor is composed of 5,6-dihydroxyindole, 5,6-dihydroxyindoline and polydihydroxyindole in a weight ratio of 2-5:2-5:

1.

8. The pigment composition according to claim 1, characterized in that The metal peroxide includes one or more of sodium peroxide, potassium peroxide, calcium peroxide, magnesium peroxide, zinc peroxide, potassium persulfate, and strontium peroxide.

9. The pigment composition according to claim 1 or 8, characterized in that In the pigment composition, the content of the peroxide is 1 wt.% to 10 wt.%.

10. The pigment composition according to claim 1, characterized in that In the pigment composition, the content of the inorganic or organic compound that is miscible or insoluble in water is 5wt.% to 60wt.%.

11. The pigment composition according to claim 1, characterized in that The surfactant includes one or more of sodium fatty acid methyl ester ethoxylate sulfonate, decyl sulfobetaine, and sodium lauroamphoacetate.

12. The pigment composition according to claim 11, characterized in that The surfactant is composed of sodium fatty acid methyl ester ethoxylate sulfonate, decyl sulfobetaine and sodium lauroamphoacetate in a weight ratio of 0.3-0.9:1:1-5.

13. The pigment composition according to claim 1, characterized in that The dosage form of the composition is one of ointment, emulsion, powder and liquid shampoo.

14. Use of the pigment composition according to any one of claims 1 to 13 in hair dyeing, hair darkening and hair care.

15. A method for dyeing, darkening and nourishing hair, characterized in that: The following steps are involved: The pigment composition according to any one of claims 1 to 13 is applied to the hair, and the hair is first rinsed after first keeping.

16. The method according to claim 15, characterized in that The first holding time is 30 to 60 minutes.

17. The method according to claim 15 or 16, characterized in that After the hair is rinsed for the first time, the dye composition according to any one of claims 1 to 13 is applied to the hair again, and the hair is rinsed for the second time.

18. The method according to claim 17, characterized in that The second holding time is 5 to 30 minutes.

19. The method according to claim 17, characterized in that The number of times of the first flushing is 1 to 2 times; the number of times of the second flushing is 1 to 2 times.

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