A method for achieving firm hair dyeing and repairing the mechanical properties of hair using curcumin

Abstract

The invention discloses a method for achieving firm hair dyeing and repairing mechanical properties of hair by using curcumin. The method of the invention is to pre-connect thiol groups by a pairing method with a hair dyeing auxiliary agent containing 2-aminoisothiazolidine hydrochloride, and then react with an auxiliary agent containing curcumin to achieve dyeing. The invention introduces free thiol groups into the hair, uses the free thiol groups to react with the conjugated double bond symmetrical structure of curcumin to generate covalent bonds, thereby improving the coloring ability and color fastness. At the same time, because the introduced curcumin has a symmetrical structure, it can combine with more thiol groups, supplementing the force lost by the breakage of disulfide bonds caused by hair dyeing and bleaching, and improving the mechanical properties of the hair.

Description

Technical Field

[0001] The invention belongs to the technical field of hair products, and in particular relates to a method for achieving firm hair dyeing and repairing the mechanical properties of hair by utilizing curcumin. Background Art

[0002] Plant-based hair dyes have been used for a long time and come from a wide range of sources. Common plant pigments in nature that can be used in hair dyes include hematoxylin, curcumin, quercetin, etc. Plant dyes have good environmental compatibility, biodegradability, and low toxicity, so more and more research has begun to focus on highlighting dyes to prepare hair dyes. There are generally two principles for hair dyeing with plant pigments: one is pigment adsorption, which can effectively deposit on the surface of the hair and will not penetrate into the inside of the hair, using physical adsorption between interfaces to make the dye adhere or deposit on the surface of the hair; the other is the complexation of plant active ingredients with metals, which connects the dye to the hair fiber through metal ions to change the color of the dye molecule.

[0003] The above two hair dyeing methods are not strong enough, which will cause the hair dye molecules to stay on the hair for a short time and be easily affected by the external environment, resulting in low color fastness of the hair dye molecules. The color will easily fade after multiple washings or sunlight.

[0004] As a kind of plant-based hair dye, curcumin has a dyeing effect. Curcumin is a yellow organic dye extracted from the ancient plant medicinal material turmeric, and its content in turmeric is about 3% to 6%. Curcumin is lipophilic, almost insoluble in water or ether, and soluble in ethanol and propylene glycol. Depending on the acidity and alkalinity, curcumin can present a variety of colors: curcumin can be dyed yellow under acidic conditions, dark orange under neutral conditions, and bright red under alkaline conditions. In traditional hair dyeing methods, curcumin adheres to the surface of hair through ordinary physical adsorption, and the stability of hair dyeing is poor. At the same time, bleaching hair causes a large number of disulfide bonds inside the hair to break, and the mechanical properties are significantly reduced. Summary of the invention

[0005] In view of the deficiencies of the prior art, the present invention provides a method for achieving firm hair dyeing and repairing the mechanical properties of hair using curcumin. The present invention introduces free thiol groups into the hair, and uses the free thiol groups to react with the conjugated double bond symmetrical structure of curcumin to generate covalent bonds, thereby improving the coloring ability and color fastness. At the same time, because the introduced curcumin has a symmetrical structure, it can bind more thiol groups, supplementing the force lost by the breakage of disulfide bonds caused by hair dyeing and bleaching, thereby improving the mechanical properties of hair.

[0006] The technical solution of the present invention is as follows:

[0007] The present invention firstly protects a hair dyeing auxiliary agent with a thiol group connected inside the hair. The hair dyeing auxiliary agent comprises 2-aminoisothiazolidine hydrochloride and has a pH value of 8-11.

[0008] Furthermore, the hair dyeing auxiliary agent also includes one or more of carbomer, hydroxyethyl cellulose and carbomer.

[0009] Furthermore, the mass fraction of 2-aminoisothiazolidine hydrochloride in the hair dyeing auxiliary is 0.5-5%, and the rest is water and other raw materials.

[0010] Furthermore, the other raw materials include one or more of a thickener and a preservative.

[0011] Furthermore, the thickener includes but is not limited to one or more of carbomer, hydroxyethyl cellulose, hydroxypropyl cellulose, guar gum, carrageenan, and sclerotium gum.

[0012] Furthermore, the preservatives include but are not limited to one or more of kasone, potassium sorbate, sodium benzoate, phenoxyethanol, pentylene glycol, and hexylene glycol.

[0013] Furthermore, the hair dyeing auxiliary agent is obtained by mixing 0.5-5% 2-aminoisothiazolidine hydrochloride, 97-99.5% water, and the rest other raw materials by mass percentage, and adjusting the pH to 8-11.

[0014] Furthermore, the hair dyeing auxiliary agent is obtained by mixing 1-1.5% hydroxyethyl cellulose, 0.5-5% 2-aminoisothiazolidine hydrochloride, 0.02-0.1% kasson and 94-98% water by mass percentage, and adjusting the pH to 8-11 with triethanolamine.

[0015] Furthermore, the hair dyeing auxiliary agent is obtained by mixing 1-1.5% hydroxyethyl cellulose, 0.5-5% 2-aminoisothiazolidine hydrochloride, 0.02-0.1% kasson and 97-98% water by mass percentage, and adjusting the pH to 8-11 with triethanolamine.

[0016] Preferably, the hair dyeing auxiliary agent is obtained by mixing 1.36% hydroxyethyl cellulose, 1% 2-aminoisothiazolidine hydrochloride, 0.02% kathoson and 97.52% water by mass percentage, and adjusting the pH to 8-11 with triethanolamine.

[0017] Furthermore, the hair dyeing auxiliary agent is obtained by mixing 0.1-2% 2-aminoisothiazolidine hydrochloride, 0.2-0.3% carbomer, and 95-99.5% water by mass percentage, and adjusting the pH to 8-11 with sodium hydroxide.

[0018] Furthermore, the hair dyeing auxiliary agent is obtained by mixing 0.5-2% 2-aminoisothiazolidine hydrochloride, 0.2-0.3% carbomer, and 97-99.5% water by mass percentage, and adjusting the pH to 8-11 with sodium hydroxide.

[0019] Preferably, the hair dyeing auxiliary agent is obtained by mixing 1% 2-aminoisothiazolidine hydrochloride, 0.25% carbomer, and 98.75% water by mass percentage, and adjusting the pH to 8-11 with sodium hydroxide.

[0020] The present invention also protects a method for introducing thiol groups into hair, wherein 2-aminoisothiazolidine hydrochloride reacts with free amino groups in hair keratin to open the ring and introduce thiol groups.

[0021] Furthermore, the free amino group includes the free amino groups in lysine and arginine present in hair keratin.

[0022] Furthermore, the reaction route involved in the method is as follows:

[0023]

[0024] In the above formula, R is -CH2CH2CH2CH2 or -CH2CH2CH2NHC=NH; when R is CH2CH2CH2CH2, it corresponds to lysine, and when R is CH2CH2CH2NHC=NH, it corresponds to arginine.

[0025] Furthermore, the method specifically comprises: coating the hair bundle with the hair dyeing auxiliary agent, leaving it to stand, rinsing, and drying to achieve access to the thiol groups inside the hair.

[0026] A hair dyeing method using curcumin to achieve firm hair dyeing and repair the mechanical properties of hair, the hair dyeing method comprising the following steps:

[0027] (1) preparing a hair dye, wherein the hair dye comprises an agent A and an agent B; the agent A is the hair dye auxiliary; and the agent B comprises a natural pigment having a conjugated double bond structure;

[0028] (2) applying agent A to the hair, leaving it to stand at room temperature, rinsing, and drying to obtain a hair bundle containing a thiol group;

[0029] (3) Apply agent B to the hair bundle of step (2), dry, keep warm, rinse, and dry to complete the hair dyeing.

[0030] Furthermore, in step (1), the mass ratio of agent A to agent B is 1:2-2:1.

[0031] Furthermore, in step (1), the mass fraction of the natural pigment in the agent B is 0.5-1.0%.

[0032] Furthermore, the natural pigment is curcumin.

[0033] Furthermore, the agent B also includes a polyol and an oil phase; the polyol includes but is not limited to one or more of propylene glycol, butylene glycol, pentylene glycol, glycerin, and dipropylene glycol; the oil phase includes but is not limited to one or more of lanolin, candelilla wax, carnauba wax, methyl linoleate, methyl laurate, methyl oleate, isopropyl myristate, cetyl alcohol, stearyl alcohol, and behenyl alcohol.

[0034] Furthermore, the agent B comprises the following components by mass percentage: 0.5-1.0% natural pigment, 75-77% polyol, and 18-27% oil phase.

[0035] Furthermore, the agent B comprises the following components by mass percentage: 75-76% propylene glycol, 18.5-21% hexadecanol, 2-3% lanolin, 2-3% methyl oleate, and 0.5-1% curcumin.

[0036] Preferably, the agent B comprises the following components by mass percentage: 75.3% propylene glycol, 19% hexadecanol, 2.1% lanolin, 2.1% methyl oleate, and 0.5% curcumin.

[0037] Furthermore, in step (2), the standing time is 15-30 min; in step (3), the drying temperature is 313-343 K, and the drying time is 0.5-1 h.

[0038] The present invention firstly utilizes 2-aminoisothiazolidine hydrochloride to react with free amino groups in hair keratin to introduce free thiol groups into the hair, and utilizes Michael reaction to chemically react with thiol groups through the symmetric structure of α-carbonyl carbon-carbon double bond of curcumin to form CS bonds, and the generated covalent bonds have higher stability. In this way, the hair dye molecules have stronger coloring ability and color fastness. The reaction route is as follows:

[0039]

[0040] In the formula, when R is -CH2CH2CH2CH2, it corresponds to lysine, and when R is -CH2CH2CH2NHC=NH, it corresponds to arginine.

[0041] In addition, curcumin is a natural molecule with symmetrical structure and two α-carbonyl carbon-carbon double bonds. Therefore, 1 mol of curcumin molecules can react with 2 mol of free thiols. When the free thiols come from different keratin chains, curcumin introduces additional covalent bonds in the hair, which can compensate for the loss of mechanical properties caused by the breaking of disulfide bonds in bleached hair, or improve the mechanical properties of healthy gray hair.

[0042] The beneficial technical effects of the present invention are:

[0043] The present invention aims at the problem of hair dyeing with plants and proposes a method of pre-attaching thiol groups and then using curcumin for hair dyeing. Compared with traditional physical adsorption hair dyeing, this method has higher color fastness and can repair the mechanical properties of hair.

[0044] The present invention uses 2-aminoisothiazolidine hydrochloride to react with hair keratin to form an external thiol group; at the same time, a curcumin pigment molecule with a conjugated double bond structure is selected, and through a thiol click reaction, the hair is dyed firmly and the mechanical properties are repaired and improved. In the hair dyeing process, the newly generated CS bond can well solve the problem of decreased hair mechanical properties caused by the breakage of the SS bond during the hair bleaching process, effectively improve the hair toughness, repair and / or protect the problem of damaged hair mechanical properties caused by disulfide bond damage caused by various damage pressures (including bleaching, perming and dyeing, pollution exposure, ultraviolet irradiation, multiple washings, high temperature, etc.); at the same time, the curcumin molecules connected by the CS covalent bond can penetrate into the hair, and have better coloring ability and color fastness. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a fluorescence micrograph of the quenching of the counter-fluorescence of iodine solution (I-3) and rhodamine B (RB) by the free thiol after external thiol in Example 1 of the present invention.

[0046] In the figure: a is a side view; b is a cross-sectional view.

[0047] Figure 2 These are fluorescence microscope photos of curcumin hair dyeing through Rhodamine B anti-fluorescence quenching in Comparative Example 1 and Example 1 of the present invention.

[0048] In the figure: a is Example 1; b is Comparative Example 1.

[0049] Figure 3 From left to right, they are photos of undyed hair bundles, dyed hair bundles of comparative example, and hair bundles of comparative example 1 and example 1 after multiple washings.

[0050] In the figure: a is an undyed hair bundle; b is a hair bundle dyed with curcumin in the comparative example; c is a hair bundle dyed with curcumin in Example 1; d is a hair bundle after multiple washings in Comparative Example 1; e is a hair bundle after multiple washings in Example 1. DETAILED DESCRIPTION

[0051] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0052] The invention connects thiol groups to the hair, and chemically reacts the thiol groups with curcumin to achieve covalent bond connection between the curcumin and the hair, thereby achieving hair dyeing. This hair dyeing method not only has high color fastness, but also can repair the mechanical properties of the hair.

[0053] In one embodiment of the present invention, the hair dyeing auxiliary agent having thiol groups implanted inside the hair comprises 2-aminoisothiazolidine hydrochloride, and the pH value of the hair dyeing auxiliary agent is 8-11.

[0054] In one embodiment of the present invention, the hair dyeing auxiliary agent further comprises carbomer, carbomer and hydroxyethyl cellulose, carbomer and kasone, kasone and hydroxyethyl cellulose, or carbomer, hydroxyethyl cellulose and kasone.

[0055] In one embodiment of the present invention, the mass fraction of 2-aminoisothiazolidine hydrochloride in the hair dyeing auxiliary is 0.5%, 1%, 2%, 3%, 4% or 5%, and the rest is water and other raw materials.

[0056] In one embodiment of the present invention, the other raw materials include one or more of a thickener and a preservative.

[0057] In one embodiment of the present invention, the thickener includes but is not limited to one or more of carbomer, hydroxyethyl cellulose, hydroxypropyl cellulose, guar gum, carrageenan, and sclerotium gum.

[0058] In one embodiment of the present invention, the preservative includes but is not limited to one or more of kasone, potassium sorbate, sodium benzoate, phenoxyethanol, pentylene glycol, and hexylene glycol.

[0059] In one embodiment of the present invention, the hair dyeing auxiliary agent is obtained by mixing 0.5% 2-aminoisothiazolidine hydrochloride, 99% water, and the rest other raw materials by mass percentage, and adjusting the pH to 8, 9, 10 or 11.

[0060] In one embodiment of the present invention, the hair dyeing auxiliary agent is obtained by mixing 2% 2-aminoisothiazolidine hydrochloride, 97% water, and the rest other raw materials, and adjusting the pH to 8, 9, 10 or 11.

[0061] In one embodiment of the present invention, the hair dyeing auxiliary agent is obtained by mixing 1% hydroxyethyl cellulose, 1.9% 2-aminoisothiazolidine hydrochloride, 0.1% kasson, and 97% water, and adjusting the pH to 8, 9, 10 or 11 with triethanolamine.

[0062] In one embodiment of the present invention, the hair dyeing auxiliary agent is obtained by mixing 1.48% hydroxyethyl cellulose, 0.5% 2-aminoisothiazolidine hydrochloride, 0.02% kasson, and 98% water, and adjusting the pH to 8, 9, 10 or 11 with triethanolamine.

[0063] In one embodiment of the present invention, the hair dyeing auxiliary agent is obtained by mixing 1.36% hydroxyethyl cellulose, 1% 2-aminoisothiazolidine hydrochloride, 0.02% kasson, and 97.62% water, and adjusting the pH to 8, 9, 10 or 11 with triethanolamine.

[0064] In one embodiment of the present invention, the hair dyeing auxiliary agent is obtained by mixing 1.36% hydroxyethyl cellulose, 1% 2-aminoisothiazolidine hydrochloride, 0.02% kathoson, and 97.62% water by mass percentage, and adjusting the pH to 8, 9, 10 or 11 with sodium hydroxide.

[0065] In one embodiment of the present invention, the hair dyeing auxiliary agent is obtained by mixing 1% 2-aminoisothiazolidine hydrochloride, 0.25% carbomer, and 98.75% water, and adjusting the pH to 8, 9, 10 or 11 with sodium hydroxide.

[0066] The method for inserting thiol groups into hair of the present invention is to react 2-aminoisothiazolidine hydrochloride with free amino groups in hair keratin to introduce thiol groups through ring opening. In one embodiment of the present invention, the free amino groups include free amino groups in lysine and arginine present in hair keratin.

[0067] The method specifically comprises: coating the hair bundle with the hair dyeing auxiliary agent, leaving it to stand, rinsing and drying, so as to achieve the access of the thiol groups inside the hair.

[0068] The hair dyeing method of the present invention for achieving firm hair dyeing and repairing the mechanical properties of hair by using curcumin comprises the following steps:

[0069] (1) preparing a hair dye, wherein the hair dye comprises an agent A and an agent B; the agent A is the hair dye auxiliary; and the agent B comprises a natural pigment having a conjugated double bond structure;

[0070] (2) applying agent A to the hair, leaving it to stand at room temperature, rinsing, and drying to obtain a hair bundle containing a thiol group;

[0071] (3) Apply agent B to the hair bundle of step (2), dry, keep warm, rinse, and dry to complete the hair dyeing.

[0072] In one embodiment of the present invention, in step (1), the mass ratio of agent A to agent B is 1:21:1, 1.5:1 or 2:1.

[0073] In one embodiment of the present invention, in step (1), the mass fraction of the natural pigment in the agent B is 0.5%, 0.75% or 1.0%.

[0074] In one embodiment of the present invention, the natural pigment is curcumin.

[0075] In one embodiment of the present invention, the agent B further includes a polyol and an oil phase; the polyol includes but is not limited to one or more of propylene glycol, butylene glycol, pentylene glycol, glycerin, and dipropylene glycol; the oil phase includes but is not limited to one or more of lanolin, candelilla wax, carnauba wax, methyl linoleate, methyl laurate, methyl oleate, isopropyl myristate, cetyl alcohol, stearyl alcohol, and behenyl alcohol.

[0076] In one embodiment of the present invention, the agent B comprises the following components by mass percentage: 0.5% natural pigment, 75% polyol, and 24.5% oil phase.

[0077] In one embodiment of the present invention, the agent B comprises the following components by mass percentage: 1.0% natural pigment, 77% polyol, and 22% oil phase.

[0078] In one embodiment of the present invention, the agent B comprises the following components by mass percentage: 76% propylene glycol, 19% hexadecanol, 2% lanolin, 2% methyl oleate, and 1% curcumin.

[0079] In one embodiment of the present invention, the agent B comprises the following components by mass percentage: 75.3% propylene glycol, 19% hexadecanol, 2.1% lanolin, 2.1% methyl oleate, and 0.5% curcumin.

[0080] In one embodiment of the present invention, in step (2), the standing time is 15 min, 20 min, 25 min or 30 min; in step (3), the drying temperature is 313j, 320k, 340k or 343k, and the drying time is 0.5h, 0.75h or 1h.

[0081] In order to explore the optimal conditions for curcumin dyeing, the present invention designs different experiments to repair bleached hair bundles pre-attached with thiol groups.

[0082] Example 1

[0083] The method of using curcumin to achieve firm hair dyeing and repair the mechanical properties of hair comprises the following steps:

[0084] (1) Preparation of hair dye

[0085] In hair dyeing, the hair dye is prepared according to Table 1, including agent A and agent B, and the mass ratio of agent A to agent B is 3:2. (In the following specific embodiments, the hair dye is configured according to the values ​​in Table 1):

[0086] Table 1 Hair dye formula

[0087]

[0088] (2) Treat the hair with agent A to give the hair free thiol groups

[0089] Use a soft small brush to evenly apply 6g of agent A on the hair at room temperature, keep it at room temperature for 0.5h, rinse it clean, and blow dry it; the hair used for dyeing here can be either natural white hair or bleached black hair (the hair used in this embodiment is bleached black hair); the bleached hair is provided by Shanghai Canyu Co., Ltd., model is Level 2 bleached Chinese / 27cm x 1g, free 25cm. The free thiol group is characterized by the principle of fluorescent labeling, the principle of which is: iodine solution (I3 - ) has a fluorescence quenching effect on rhodamine B, which weakens or even eliminates the fluorescence signal intensity, and the thiol group in the hair cysteine ​​molecule can - Reduced to I-, the fluorescence signal of the system reappears. Figure 1 and Figure 2 Figure a. Figure 1 It can be seen that neither natural white hair nor bleached hair has free thiol groups. When the hair is treated with agent A, free thiol groups (fluorescent) are formed, which lays a solid foundation for curcumin to dye hair firmly.

[0090] (3) Use agent B

[0091] Use the same method to evenly apply 4 g of agent B on the hair treated in step (2), wrap it with plastic wrap and keep it at 343K for 1 hour, rinse it clean, blow dry it, and dye it to obtain dyed hair.

[0092] Embodiment 2:

[0093] The method of using curcumin to achieve firm hair dyeing and repair the mechanical properties of hair comprises the following steps:

[0094] (1) Preparation of hair dye

[0095] In hair dyeing, a hair dye is prepared according to Table 1, including agent A and agent B.

[0096] (2) Treat the hair with agent A to give the hair free thiol groups

[0097] Use a soft small brush to evenly apply 6g of agent A on the hair at room temperature, keep it at room temperature for 0.5h, rinse it clean, and blow dry; the hair used for dyeing here is bleached black hair;

[0098] (3) Using the same method, 4 g of agent B is evenly applied to the hair treated in step (2), wrapped with plastic wrap and kept at 313 K for 1 hour, rinsed, blow-dried, and dyed hair is obtained.

[0099] Embodiment 3:

[0100] The method of using curcumin to achieve firm hair dyeing and repair the mechanical properties of hair comprises the following steps:

[0101] (1) Preparation of hair dye

[0102] In hair dyeing, the hair dye is prepared according to Table 2, including agent A and agent B.

[0103] Table 2 Hair dye formula

[0104]

[0105] (2) Treat the hair with agent A to give the hair free thiol groups

[0106] Use a soft small brush to evenly apply 6g of agent A on the hair at room temperature, keep it at room temperature for 0.5h, rinse it clean, and blow dry; the hair used for dyeing here is bleached black hair;

[0107] (3) Using the same method, 4 g of agent B is evenly applied to the hair treated in step (2), wrapped with plastic wrap and kept at 343 K for 1 hour, rinsed, blow-dried, and dyed hair is obtained.

[0108] Embodiment 4:

[0109] The method of using curcumin to achieve firm hair dyeing and repair the mechanical properties of hair comprises the following steps:

[0110] (1) Preparation of hair dye

[0111] In hair dyeing, a hair dye is prepared according to Table 1, including agent A and agent B.

[0112] (2) Treat the hair with agent A to give the hair free thiol groups

[0113] Use a soft small brush to evenly apply 6g of Agent A on the hair at room temperature, keep it at room temperature for 15 minutes, rinse it off, and blow dry it; the hair used for dyeing here can be either natural white hair or bleached black hair;

[0114] (3) Using the same method, 4 g of agent B is evenly applied to the hair treated in step (2), wrapped with plastic wrap and kept at 343 K for 0.5 h, rinsed, blow-dried, and dyed hair is obtained.

[0115] Comparative Example 1: (same as Example 1, except that the 2-aminoisothiazolidine hydrochloride mentioned in the present invention is not added to Agent A)

[0116] The traditional curcumin dyeing method includes the following steps:

[0117] (1) Preparation of hair dye

[0118] In hair dyeing, the hair dye is prepared according to Table 3, including agent A and agent B. (In the following specific embodiments, the hair dye is configured according to the values ​​in the table):

[0119] Table 3 Hair dye formula

[0120]

[0121] (2) Hair treated with Agent A

[0122] Use a small soft brush to evenly apply 6 g of Agent A to the hair at room temperature, keep it at room temperature for 0.5 h, rinse it clean, and blow it dry; since it does not contain 2-aminoisothiazolidine hydrochloride, it is impossible to connect the thiol group through a chemical reaction.

[0123] (3) Hair treated with Agent B

[0124] Use the same method to evenly apply 4 g of agent B on the hair treated in step (2), wrap it with plastic wrap and keep it at 343K for 1 hour, rinse it clean, blow dry it, and dye it to obtain dyed hair.

[0125] Thus, a traditional method curcumin hair dyeing sample was obtained.

[0126] Similar to Example 1, the free thiol groups of this comparative example were characterized by the principle of fluorescent labeling. Figure 2 As shown in b.

[0127] Comparative Example 2:

[0128] The method of using anthocyanins to achieve firm hair dyeing while repairing the mechanical properties of hair comprises the following steps:

[0129] (1) Preparation of hair dye

[0130] In hair dyeing, the hair dye is prepared according to Table 3, including agent A and agent B. (In the following specific embodiments, the hair dye is configured according to the values ​​in the table):

[0131] Table 4 Hair dye formula

[0132]

[0133] (2) Hair treated with Agent A

[0134] Use a small soft brush to evenly apply 6 g of Agent A on the hair at room temperature, keep it at room temperature for 0.5 h, rinse it off, and blow dry it.

[0135] (3) Hair treated with Agent B

[0136] Use the same method to evenly apply 4 g of agent B on the hair treated in step (2), wrap it with plastic wrap and keep it at 343K for 1 hour, rinse it clean, blow dry it, and dye it to obtain dyed hair.

[0137] Thus, anthocyanin hair dyeing sample was obtained.

[0138] Comparative Example 3:

[0139] The method of using curcumin to achieve firm hair dyeing and repair the mechanical properties of hair comprises the following steps:

[0140] (1) Preparation of hair dye

[0141] In hair dyeing, a hair dye is prepared according to Table 1, including agent A and agent B.

[0142] (2) Treat the hair with agent A to give the hair free thiol groups

[0143] Use a soft small brush to evenly apply 6g of agent A on the hair at room temperature, keep it at room temperature for 0.5h, rinse it clean, and blow dry it; the hair used for dyeing here can be either natural white hair or bleached black hair;

[0144] (3) Treatment with agent B

[0145] Use the same method to evenly apply 4g of agent B on the hair treated in step (2), wrap it with plastic wrap and treat it at room temperature for 1 hour, rinse it clean, blow dry it, and dye it to obtain hair dyed at room temperature.

[0146] Comparative Example 4:

[0147] A method for achieving firm hair dyeing and repairing the mechanical properties of hair using curcumin (same as Example 1, except that the reaction time of agent A in Example 1 is changed to 0.2 h, and the reaction time of agent B is changed to 0.1 h, and insufficient time leads to poor dyeing), the specific steps are as follows:

[0148] (1) Preparation of hair dye

[0149] In hair dyeing, a hair dye is prepared according to Table 1, including agent A and agent B.

[0150] (2) Treat the hair with agent A to give the hair free thiol groups

[0151] Use a soft small brush to evenly apply 6g of agent A on the hair at room temperature, keep it at room temperature for 0.2h, rinse it clean, and blow dry it; the hair used for dyeing here can be either natural white hair or bleached black hair;

[0152] (3) Treatment with agent B

[0153] Use the same method to evenly apply 4g of agent B on the hair, wrap it with plastic wrap, treat it at 343K for 0.1h, rinse it, blow dry it, and the dyeing is completed. The hair is dyed at room temperature.

[0154] Test example:

[0155] (1) Characterization of hair dyeing effect:

[0156] The color characteristic values ​​L*, a*, b*, c*, and h* of the hair after dyeing in the embodiment and the comparative example were measured by a colorimeter, and the data under the CIE standard light source D65 and a 90° viewing field were used for calculation. Among them, L* indicates lightness, black has the lowest lightness, white has the highest lightness, and different grays are distributed in between; a* indicates the color index from red to green, red is a positive value, and green is a negative value; b* indicates the color index from blue to yellow, blue is a negative value, and yellow is a positive value; c* indicates saturation, and the larger the c* value, the higher the color vividness; h* indicates hue, which is a color angle between 0-360°, 0-90° is red, orange, and yellow, 90-180° is yellow, yellow-green, and green, 180-270° is green, cyan, and blue, and 270-360° is blue, purple, magenta, and red. The hair dyeing effects of the embodiment and the comparative example are recorded in Table 5.

[0157] In order to examine the durability of hair dye, the hair was washed to simulate the daily cleaning process, with 0.2g shampoo per gram of hair bundle or the amount in accordance with the sample usage method, and rinsed with warm water after 5 minutes. Each time the warm water was rinsed, the hair was brushed ten times with similar force by hand, and then dried under constant temperature and humidity conditions. This was one operation, and the washing cycle was repeated 7 times. The color difference between the comparative example and the comparative example before and after washing is represented by the color difference ΔE, ΔE=[(ΔL*) 2 +(Δa*) 2 +(Δb*) 2 ] 1 / 2 , the specific results are shown in Table 5 below.

[0158] Table 5 Color difference of different hair strands

[0159] L* a* b* c* h* △E Bleached hair strands 63.09 11.88 27.71 30.14 66.79 - Example 1 60.33 19.83 59.84 63.04 71.66 - Example 1 Washing 60.21 16.68 54.39 56.81 72.93 6.29 Example 2 60.55 19.86 60.25 63.11 71.53 - Example 2 Washing 60.11 16.44 54.85 57.73 72.68 6.41 Example 3 60.33 19.8 59.85 63.2 71.54 - Example 3 Washing 60.19 16.7 54.42 56.93 73.01 6.25 Example 4 60.25 19.75 59.74 63.05 71.54 - Example 4 Washing 60.08 16.54 53.79 55.71 72.89 6.76 Comparative Example 1 64.03 13.1 40.65 42.7 70.1 - Comparative Example 1 Washing 63.88 11.56 32.17 36.2 70.7 8.62 Comparative Example 2 64.03 12.5 38.79 43.52 72.83 - Comparative Example 2 Washing 62.48 11.02 30.16 37.5 70.46 8.89 Comparative Example 3 63.83 19.35 38.64 43.22 72.63 - Comparative Example 3 Washing 62.28 16.17 30.01 37.35 70.26 9.33 Comparative Example 4 61.42 18.99 35.94 43.25 71.74 - Comparative Example 4 Washing 58.87 15.21 26.84 37.03 69.87 10.18

[0160] The above results show that the initial color of Examples 1-4 after dyeing is fuller and more inclined to red and yellow, and the color difference before and after washing is generally lower than 6.8, while the initial color of Comparative Examples 1-4 after dyeing is relatively less full. The color is lighter, and the color difference before and after washing is higher than 8.5. This shows that Examples 1-4 are more solid than Comparative Examples 1-4, indicating that the curcumin hair dyeing method proposed in the present invention can achieve a solid hair dyeing ability of external thiol dyeing better than direct hair dyeing. Comparing Examples 1-4, it can be seen that both Examples 1 and 3 are better, and Example 3 has the best effect.

[0161] Figure 3 The damaged hair is the bleached hair bundle used in the present invention, the direct hair dyeing is comparative example 1, the pre-mercapto dyeing is embodiment 1, the direct hair dyeing is washed seven times is comparative example 1, the pre-mercapto dyeing is washed seven times is embodiment 1. Figure 3 It can be seen that Example 1 has better color fastness than Comparative Example 1, and the color can still be maintained after multiple washings.

[0162] (2) Tensile properties test:

[0163] The hair bundles treated by the above different methods (4 embodiments and 4 comparative examples, and untreated black hair and bleached hair, a total of 10 hair bundles) were tested for tensile properties. The specific testing method is as follows: 30 hair strands with a diameter difference of less than 10 μm were taken from each hair bundle, and a single fiber strength test was performed using a fiber strength tester.

[0164] First, select the hair and use the SN-1200W high-definition camera to measure the diameter of the hair. The specific method is to take the average of the diameters at three locations in the middle. Then test the tensile strength and calculate and compare the tensile strength of the control group and each sample group using the following formula:

[0165] σ=F b / S o

[0166] Where: σ is the tensile strength, unit MPa, F b The maximum force that the sample bears when it is broken, in N, S o is the original cross-sectional area of ​​the sample, in cm 2 The results of the hair tensile strength test are shown in Table 6. The healthy hair bundles were provided by Shanghai Canyu Co., Ltd., with the model of Natural Black Chinese / 18cm x 1g, free 16cm, and the bleached hair bundles were provided by Shanghai Canyu Co., Ltd., with the model of Level 2 bleached Chinese / 27cm x 1g, free 25cm.

[0167] Table 6 Mechanical properties of different hair bundles

[0168]

[0169]

[0170] As shown in Table 6, the tensile strength of Examples 1-4 and healthy hair is significantly higher than that of Comparative Examples 1-4 and bleached hair bundles, indicating that curcumin can optimize the mechanical properties of hair when used for click reaction to connect thiol groups. The decrease in the mechanical properties of damaged hair bundles may be due to the breakage of disulfide bonds, which makes the hair easier to break. These situations are well improved after curcumin hair dyeing and repair, so we can judge that the synthesized molecule achieves the effect of improving the tensile strength of hair by click reaction with free thiol groups on hair.

[0171] The above is only a preferred embodiment of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

Claims

1. A hair dyeing method using curcumin to achieve firm hair dyeing and repair the mechanical properties of hair, characterized in that: The hair dyeing method comprises the following steps: (1) Preparing a hair dye, the hair dye comprising agent A and agent B; the agent A is a hair dyeing auxiliary; the agent B comprises a natural pigment having a conjugated double bond structure; (2) applying agent A to the hair, leaving it at room temperature, rinsing it, and drying it to obtain a hair bundle containing a thiol group; (3) applying agent B to the hair bundles in step (2), drying, keeping warm, rinsing, and drying to complete the hair dyeing; In step (1), the mass ratio of agent A to agent B is 1:2-2:1; In step (1), the mass fraction of natural pigment in the agent B is 0.5-1.0%; The natural pigment is curcumin; In step (2), the standing time is 15-30 min; in step (3), the drying temperature is 313-343 K, and the insulation time is 0.5-1 h; The hair dyeing auxiliary comprises 2-iminothiolane hydrochloride, and the pH value of the hair dyeing auxiliary is 8-11.

2. The hair dyeing method according to claim 1, characterized in that: The hair dyeing auxiliary agent also includes one or more of carbomer, hydroxyethyl cellulose and carbomer.

3. The hair dyeing method according to claim 1, characterized in that: The mass fraction of 2-iminothiolane hydrochloride in the hair dyeing auxiliary agent is 0.5-5%.

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