Method for hair shaping treatment that is hair straightening treatment or permanent waving treatment, and hair treating liquid for hair shaping treatment

Abstract

A method for shaping hair by a curly hair-correction treatment or a permanent waving treatment, said method comprising a step for applying a first agent containing a reducing agent to the hair and then allowing to stand for a preset time, a step for washing off the first agent applied to the hair, a step for applying an oxidative second agent containing an oxidizing agent to the hair and then allowing to stand for a preset time, and a step for washing off the second agent applied to the hair, wherein the method for shaping hair further comprises a step for applying a gold nanoparticle-containing hair treatment solution to the hair. A gold nanoparticle-containing hair treatment solution for shaping hair, said hair treatment solution being to be applied to the hair in a treatment for shaping hair

Description

A hair shaping treatment method that is a hair straightening treatment or a permanent wave treatment, and a hair treatment liquid for hair shaping treatment The present invention relates to a hair treatment liquid for alleviating damage to hair during the application of a hair shaping treatment such as a hair straightening treatment or a permanent wave treatment, and a hair shaping treatment method using the same. Conventionally, a hair shaping treatment method using a perm solution composed of a combination of a first agent containing a reducing agent and a second agent containing an oxidizing agent is widely known. Specifically, a hair straightening treatment, which is a beauty technique for correcting curly hair to straight hair, and a permanent wave treatment for giving hair a shape such as curls or waves are known. Generally, the following basic principles are used in the hair shaping treatment method. First, by applying a first agent containing a reducing agent such as thioglycolic acid to the hair, the disulfide bonds (cystine bonds) that crosslink keratin constituting the hair are cleaved. By cleaving the disulfide bonds and eliminating the crosslinked structure of keratin, the restraint due to the crosslinking of keratin is eliminated. After shaping the hair in a state where the crosslinked structure of keratin has been eliminated, by applying a second agent containing an oxidizing agent such as hydrogen peroxide solution or sodium bromate, the disulfide bonds are reformed. By reforming the disulfide bonds in the shaped state and crosslinking keratin, the shape of the hair after shaping is fixed. In the case of a hair straightening treatment, after applying an iron press treatment to the hair after cleaving the disulfide bonds to give it a straight shape, the disulfide bonds are reformed. By reforming the disulfide bonds after shaping the hair into a straight shape, the straight shape of the hair is fixed. Also, in the case of a permanent wave treatment, by applying the first agent to the hair and leaving it for a predetermined time, the disulfide bonds are cleaved. Then, after rinsing off the first agent, by applying the second agent to the hair with the hair wound around a cylindrical rod for giving a shape such as a wave, the disulfide bonds are reformed and the permanent wave of the hair is fixed. In such a hair shaping treatment method using a perm solution, there were cases where, contrary to expectations before the treatment, excessive stress was imposed on the hair. Specifically, split hair might occur due to a decrease in hair strength, or brittle hair might occur with fine undulations and breakage. Particularly in areas prone to damage, such as the front hair or the hair around the collar, brittle hair and split hair were likely to occur. The cause of such brittle hair and split hair is thought to be that, for hair damaged by hair dyeing or past hair shaping treatments, further damage is caused by, for example, an overly long standing time after applying the first agent, or an inappropriate selection of the agent. When performing the treatment, the operator conducts counseling with the subject over time, understands the hair quality, the strength of the curl, the history of treatments the hair has received, etc., and selects the agent, determines the area to which the agent is to be applied, selects the standing time, etc. Further, the operator performs the treatment with great care while checking the state of the hair, such as the degree of softening after applying the first agent. However, cases where unexpected brittle hair and split hair occurred continued to occur. Patent Document 1 below discloses a hair straightening treatment method capable of achieving appropriate hair straightening, suppressing deterioration of hair texture, or suppressing damage to hair. The method uses a first agent containing a reducing agent and an alkaline agent and a second agent containing an oxidizing agent. Before applying the first agent to the hair, during the standing time after applying the first agent to the hair, or at least before applying the second agent to the hair, a hair straightening auxiliary agent containing hydrogen water with a hydrogen concentration of 1% by mass or more is applied to the hair. Further, when the hair straightening auxiliary agent contains a noble metal colloid such as platinum colloid or palladium colloid, it is disclosed that the noble metal colloid acts as a catalyst for promoting the reaction between high-concentration hydrogen water and hydroxyl radicals, or acts as a catalyst for decomposing hydrogen peroxide as an oxidizing agent. Japanese Patent Application Laid-Open No. 2015-17064 An object of the present invention is to provide a hair treatment liquid and a hair shaping treatment method for suppressing damage caused by treatment in hair shaping treatments such as hair straightening treatment and permanent wave treatment. One aspect of the present invention is a hair shaping treatment method comprising at least the steps of applying a first agent containing a reducing agent to hair and leaving it for a predetermined time, rinsing off the first agent applied to the hair, applying a second agent containing an oxidizing agent to the hair and leaving it for a predetermined time, and rinsing off the second agent, further comprising the step of applying a hair treatment liquid containing gold nanoparticles to the hair. According to such a hair shaping treatment method, the frequency of occurrence of frizzy hair and split ends can be significantly reduced. Also, the hair to which the hair treatment liquid containing gold nanoparticles is applied is excellent in shape retention and combability. In hair shaping treatments such as hair straightening treatments and permanent wave treatments, the disulfide bond (—S—S—) of keratin is reduced to a thiol group (—SH) by a reducing agent contained in the first agent. The cross-linked structure of keratin is eliminated by the reduction of the disulfide bond. Then, the hair is shaped in a state where the cross-linked structure of keratin is eliminated, and the thiol group (—SH) of keratin is oxidized by treating the shaped hair with the second agent to reform the disulfide bond (—S—S—). This reaction is a reversible redox reaction as shown in Chemical Formula 1 below: It is a reversible redox reaction as shown. The present inventors have found that the frequency of occurrence of frizzy hair and split ends can be significantly reduced by the method described above. And they considered the mechanism as follows. By applying the first agent to the hair and reducing the disulfide bond, a thiol group having high nucleophilicity is generated. Since the thiol group has high nucleophilicity, it tries to quickly shift to a stable oxidation state. At this time, if the reduction proceeds too rapidly, the oxidation reaction also proceeds rapidly, resulting in the reformation of a disulfide bond between thiol groups that should not originally react, or the formation of an oxidation product that does not form a cross-linked structure by reacting with oxidizing substances or air contained in the hair. As a result, it is considered that frizzy hair and split ends are generated by forming a cross-linked structure that leaves distortion in keratin or generating an oxidation product that cannot form a cross-linked structure. The generation of split ends and broken hairs is likely to occur when the standing time in the reduced state after applying the first agent is too long compared to the appropriate time, or when a strong agent is selected. The appropriate standing time and the optimal agent after applying the first agent vary depending on the degree of damage the hair has received. For hair with little damage, damage is less likely to become apparent even if it is left standing for a relatively long time or a strongly alkaline agent is used. On the other hand, for hair with significant damage, damage is likely to become apparent in a short time. That is, it is considered that hair with significant damage is likely to form a cross-linked structure that leaves distortion or to generate oxidation products that cannot form a cross-linked structure. The inventors of the present invention have found that when gold nanoparticles are present when applying the first agent in a hair straightening treatment or a permanent wave treatment, as shown in the following Chemical Formula 2: It is considered that the nucleophilicity is suppressed by the coordination of gold to sulfur in the thiol group (-SH) and stabilization. This was obtained from the finding that the reduction rate of the thiol group (-SH) becomes moderate when gold nanoparticles are present. By slowly proceeding the reduction reaction, the rapid oxidation reaction due to the nucleophilicity of the thiol group (-SH) is also suppressed, and as a result, it becomes difficult to form a cross-linked structure that leaves distortion or to form unfavorable oxidation products. As a result, it has been found that when the first agent is applied in the presence of gold nanoparticles and a hair straightening treatment or a permanent wave treatment is performed, the frequency of occurrence of split ends and broken hairs is significantly reduced. The concentration of gold nanoparticles in the hair treatment liquid is preferably 0.0001% by mass or more, because the generation of split ends and broken hairs can be more effectively suppressed by sufficiently controlling unfavorable reactions. Also, when the hair treatment liquid further contains platinum nanoparticles, it is preferable because the platinum nanoparticles act as a catalyst for decomposing hydrogen peroxide which is an oxidizing agent. Also, it is preferable to include the step of applying the hair treatment liquid to the hair before applying the second agent to the hair, because it can suppress the rapid progress of the reduction reaction of the disulfide bonds of keratin. Further, the first agent preferably has a pH of 5 to 8 in terms of suppressing the cleavage of ionic bonds in keratin, which is one of the causes of the generation of split ends and broken hairs. Further, the hair shaping treatment method is a hair straightening treatment method, and it is preferable that the method further includes a step of correcting the hair rinsed with the first agent into straight hair while heating. According to such a hair straightening treatment method, the frequency of the generation of split ends and broken hairs can be significantly reduced. Further, as a secondary effect, since the hair coated with the hair treatment liquid containing gold nanoparticles is excellent in combability, the formability is improved. Further, the hair straightening treatment method preferably further includes a step of drying the hair rinsed with the first agent and combing the hair while spray-applying the hair treatment liquid to the hair. In the hair straightening treatment, in many cases, a combing step of shaping the hair straight before drying the hair after rinsing with the first agent is provided. In such a combing step, the damage to the hair may increase. In the case of healthy hair, it is not easily entangled during combing and the combability is good. On the other hand, in the case of damaged hair that already contains split ends, broken hairs, and many branched hairs before the treatment, it is easily entangled during combing and the combability may become extremely poor. In such a case, if the speed of moving the comb is too fast, the hair may be damaged due to frequent entanglement of the hair. By applying gold nanoparticles to the hair before or during combing, the combability of the hair becomes extremely good. As a result, the damage to the hair caused by combing can be suppressed. Further, the heating of the hair is preferably performed with a hair iron set at 110 to 180°C. In the hair straightening treatment, heating with a hair iron often employs a high temperature of about 180 to 200°C. Heating with a high-temperature hair iron damages the hair. Since the hair coated with the hair treatment liquid containing gold nanoparticles has improved formability, it can be sufficiently shaped even with a hair iron set at a low temperature of 110 to 180°C. The inventors believe that the reason is that gold, which has an extremely high thermal conductivity, improves the heat transfer efficiency of the hair iron. Further, the hair shaping treatment method is a permanent wave treatment method, and preferably further includes a step of shaping the hair by winding it around a rod. According to such a permanent wave treatment method, the frequency of occurrence of split ends and frizzy hair can be significantly reduced. Also, when the rod is removed from the hair wound around the rod, the firmness of the hair is maintained. Therefore, a permanent wave treatment capable of firmly maintaining the ridge feeling can be realized. Also, even when further including a step of heating the rod to 50° C. or higher with the hair wound around the rod, as in the so-called digital perm, it is preferable in that the damage imparted to the hair can be reduced. Another aspect of the present invention is a hair shaping treatment that is a permanent wave treatment or a hair straightening treatment, and is a hair treatment liquid applied to the hair, which is a hair treatment liquid for hair shaping treatment containing gold nanoparticles. Such a hair treatment liquid is preferable in that it can reduce the damage received by the hair during or after the hair shaping treatment such as a hair straightening treatment or a permanent wave treatment. According to the present invention, in the application of a hair straightening treatment or a permanent wave treatment, the damage imparted to the hair that causes frizzy hair and split ends can be reduced. It is a flowchart for explaining the flow of the hair straightening treatment of the first embodiment. It is a flowchart for explaining the flow of the permanent wave treatment of the second embodiment. It is an explanatory diagram for explaining the retention of the ridge feeling of the hair when the hair is removed from the rod during the permanent wave treatment of the second embodiment. [First Embodiment] As a hair shaping treatment method according to the present invention, an embodiment of a hair straightening treatment method will be described in detail with reference to the drawings. FIG. 1 is a flowchart for explaining the process flow of the hair straightening treatment method of the present embodiment. In the method for straightening curly hair according to this embodiment, first, a first agent containing a reducing agent is applied to the hair (s1), and the hair is left for a predetermined time (s2) to reduce the disulfide bonds that crosslink the keratin forming the hair to thiol groups (-SH). In this step, by cleaving the crosslinked structure formed by the disulfide bonds formed in a distorted state so as to form curly hair, the degree of freedom of the molecular chains of keratin is improved. The first agent contains a reducing agent and other components that are blended as necessary. Specific examples of the reducing agent include, for example, thioglycolic acid, thioglycolates such as sodium thioglycolate and ammonium thioglycolate, thiolactic acid, cysteine, cysteamine, acetylcysteine, thioglycerol, sulfites, and the like. In addition, other components that are blended as necessary include cream bases such as cetanol, alkaline agents that swell the hair and open the cuticle to promote the penetration of the reducing agent, nonionic surfactants that improve the permeability of the reducing agent and function as emulsifiers for each component, cationic surfactants to impart slipperiness to the hair, oily components such as lanolin, NMF (natural moisturizing factor) and other moisturizing agents, treatment components composed of proteins and polypeptides that are their hydrolyzates, amino acids, and the like. These may be used alone or in combination of two or more. Specific examples of the alkaline agent include, for example, aqueous ammonia, ammonium carbonate, sodium carbonate, monoethanolamine, ammonium hydrogen carbonate, arginine, and the like. Among these, aqueous ammonia and aqueous ammonium hydrogen carbonate are particularly preferred. In the method for straightening curly hair according to this embodiment, from the viewpoint of reducing the damage to the hair, it is preferable that the first agent does not contain an alkaline agent or contains a small amount of an alkaline agent. When a first agent with a strong alkalinity is used, the ionic bonds of keratin tend to be cleaved, and split ends and broken hair are likely to occur. Therefore, in the method for straightening curly hair according to this embodiment, the first agent preferably has a pH of 5 to 8, more preferably a pH of 5 to 7, and particularly preferably a pH of 5 to 6.5. The hair coated with the first agent is wrapped if necessary and then left for a predetermined time (s2). At this time, it is preferable to shape the hair into straight hair by combing if necessary. The leaving time is determined while checking the change in the softness of the hair according to the hair quality, the strength of the curl, the degree of damage the hair has received, etc. Generally, it is preferably left for 5 to 30 minutes, more preferably 10 to 30 minutes, and particularly preferably about 15 to 20 minutes. Also, when the hair has a strong curl, etc., it may be left while heating within a range that does not damage the hair if necessary. Then, after applying the first agent to the hair as described above and leaving it for a predetermined time, the first agent is rinsed off by washing with water or, if necessary, shampooing (s3). Then, preferably, while combing the wet hair after washing or before combing, a hair treatment liquid containing gold nanoparticles as an auxiliary agent for hair straightening is applied to part or all of the hair (s4). By combing and stretching the wet hair after washing, the effect of the hair straightening treatment is improved. At this time, by applying the hair treatment liquid containing gold nanoparticles, the generation of frizzy hair and split ends can be suppressed. The hair coated with the hair treatment liquid containing gold nanoparticles has good combability. When combing, the damaged state of the hair may become apparent to some extent. In the case of hair in good condition, it is not easily entangled during combing and the combing goes well. On the other hand, in the case of hair in poor condition, it is easily entangled during combing and the combing is often poor. When the combing is poor, if the comb is moved quickly, the hair is frequently entangled and caught, and further damage is caused to the hair. In such a case, the hair coated with the hair treatment liquid containing gold nanoparticles has significantly better combing. As a result, the occurrence of damage during combing, which is one of the causes of the generation of frizzy hair and split ends, can be suppressed. The hair treatment liquid containing gold nanoparticles is, for example, an aqueous treatment liquid containing a gold nanocolloid in which gold nanoparticles with a particle size of about several tens of nm are dispersed in an aqueous medium. The particle size of the gold nanoparticles is not particularly limited as long as they are gold nanoparticles forming the colloid. However, from the viewpoint of easy availability, colloids containing gold nanoparticles with a particle size of 1 to 500 nm, more preferably 5 to 300 nm, particularly 10 to 100 nm, and especially about 10 to 50 nm are preferred. The hair treatment liquid to be applied preferably contains gold nanoparticles at a high concentration of 0.00001% by mass or more, more preferably 0.0001% by mass or more, and particularly preferably 0.001% by mass or more. When a hair treatment liquid containing a high concentration of gold nanoparticles is used, the effects of suppressing the generation of split ends and broken hairs and improving combability are significantly enhanced. Also, the upper limit of the gold nanoparticles in the hair treatment liquid is not particularly limited, but from the viewpoints of cost performance and colloid stability, it is preferably 0.1% by mass, more preferably 0.01% by mass. In addition, the hair treatment liquid may contain a platinum nanocolloid together with the gold nanocolloid. The platinum nanocolloid is preferable because it functions as a catalyst for promoting the decomposition of hydrogen peroxide when hydrogen peroxide solution is used as an oxidizing agent. In this embodiment, an example of applying a hair treatment liquid containing gold nanoparticles to wet hair after washing (s3) has been described. When the hair treatment liquid containing gold nanoparticles is applied to wet hair before the step of applying the second agent, particularly after washing the first agent, it is particularly preferable because it can suppress the rapid progress of the reduction reaction before split ends and broken hairs become apparent. On the other hand, the application of the hair treatment liquid containing gold nanoparticles may be carried out at any step from before the application of the first agent to the end of the treatment, or after the treatment. Also, it may be applied not once but in multiple portions. The oxidation-reduction reaction by the hair straightening treatment is not completed immediately after the treatment but is thought to proceed for several days after the treatment. Therefore, it exhibits the effect of suppressing an undesirable oxidation-reduction reaction at any time before, during, and after the treatment. Incidentally, the amount of the hair treatment liquid containing gold nanoparticles applied to the hair cannot be specified unconditionally because it depends on the amount of hair. However, in one treatment, it is preferable to apply it little by little repeatedly using a spray or the like. Specifically, for example, it is preferable to apply it so that, for example, gold nanoparticles adhere in an amount of 0.01 to 100 mg, more preferably 1 to 10 mg, and particularly preferably about 2 to 10 mg. Then, it is dried using a hair dryer (s5). The drying conditions are not particularly limited, but for example, it is preferable to dry the hair at a temperature of about 100 to 150°C. Also, during drying, parts with significant damage may become apparent. In such a case, in order to more effectively suppress the generation of split ends and broken hairs, a hair treatment liquid containing gold nanoparticles may be locally applied to the parts where the damage has become apparent. Then, the dried hair is heat-corrected to straight hair (s6). The step of heat-correcting the hair to straight is a step of shaping the hair straight by ironing the hair containing keratin whose cross-linked structure by disulfide bonds has been eliminated by the first agent. The set temperature for the ironing treatment is not particularly limited, but it is preferably performed at a temperature of about 100 to 200°C. Also, during heat correction, parts with significant damage may become apparent. In such a case, in order to more effectively suppress the generation of split ends and broken hairs, a hair treatment liquid containing gold nanoparticles may be locally applied to the parts where the damage has become apparent. Incidentally, in the hair shrinking and correcting treatment of this embodiment, in particular, it is preferably performed with a low-temperature hair iron at a set temperature of 110 to 180°C, more preferably about 150 to 170°C. In the heat correction treatment using a hair iron, a high temperature of about 180 to 200°C is widely adopted. However, since the hair to which the hair treatment liquid containing gold nanoparticles is applied has improved formability, it can be sufficiently shaped even with a low-temperature hair iron. The inventors believe that the reason is that gold has a higher thermal conductivity (318 W / (m / K) 300K) than many other metals, so as to improve the heat transfer efficiency of the hair iron. Then, a second agent containing an oxidizing agent is applied to the hair corrected to straight and left for a predetermined time (s7). The second agent can be used without particular limitation as long as it is an oxidizing agent conventionally used for hair straightening treatment. Specific examples of such oxidizing agents include, for example, hydrogen peroxide solution and bromate. As hydrogen peroxide solution, it is usually contained at 2.5% or less within the range of pH 2.5 to 4.5, and as bromate, it is preferably contained at 3.2% or more within the range of pH 4.0 to 9.0. Then, after applying the second agent to the hair and leaving it for a predetermined time, a disulfide bond is re-formed in the hair corrected to straight hair (s8). Then, after leaving it for a predetermined time, the second agent is rinsed off by washing the hair (s9). In washing, shampooing and treatment are performed as necessary. Then, after washing, drying such as towel drying and air drying is performed (s10). Through the above steps, the hair straightening treatment of this embodiment that suppresses the generation of frizzy hair and split ends is performed. [Second Embodiment] As a hair shaping treatment method according to the present invention, an embodiment of a permanent wave treatment method will be described in detail. Conventionally, when performing a permanent wave treatment, when the operator performs the treatment, the operator conducts counseling with the subject over time, grasps the hair quality, the strength of the habit, the history of damage received by the hair, etc., and if it is determined that there is a high possibility of damage such as frizzy hair and split ends occurring when performing a permanent wave treatment, the operator may abandon the treatment. According to the permanent wave treatment method of this embodiment, since it is possible to suppress the occurrence of damage such as frizzy hair and split ends even for hair with a large amount of damage, the level of determination to abandon such a treatment can be further relaxed. Further, according to the permanent wave treatment method of this embodiment, the shapeability during the permanent wave treatment is excellent, and a wave ridge feeling close to the state assumed before the treatment can be produced. Furthermore, the texture after the treatment is also good. FIG. 2 is a flowchart for explaining the process flow of the permanent wave treatment method of this embodiment. In the permanent wave treatment method of the present embodiment, before applying the first agent in the permanent wave treatment and until before applying the second agent to the hair, a step of applying a hair treatment liquid containing gold nanoparticles to the hair, which is the same as that described in the first embodiment, is provided. In the permanent wave treatment method of the present embodiment, as an example, first, a hair treatment liquid containing gold nanoparticles is applied to the hair (s11). Then, the hair coated with the hair treatment liquid containing gold nanoparticles is wound around a cylindrical rod having an appropriate diameter for giving a wave shape (winding) (s12). Then, the first agent is applied to the hair wound around the rod (s13) and left for a predetermined time (s14). By applying the first agent and leaving it for a predetermined time, the disulfide bond that crosslinks keratin is reduced to a thiol group. In this step, by cutting the crosslinked structure by the disulfide bond, freedom is given to the molecular chain of keratin. At this time, a hair treatment liquid containing gold nanoparticles may be further applied to the hair coated with the first agent. The first agent is the same as that described in the hair straightening treatment method described in the first embodiment. Further, from the viewpoint of suppressing the generation of split ends and broken hairs, it is preferably free of an alkaline agent. When the first agent is made alkaline by containing an alkaline agent, the ionic bonds of keratin are broken, the strength of the hair decreases, and split ends and broken hairs tend to occur easily. Therefore, also in the permanent wave treatment method of the present embodiment, the first agent preferably has a pH of 5 to 8, more preferably pH 5 to 7, and particularly preferably pH 5 to 6.5. The hair wound around the rod coated with the first agent and the hair treatment liquid containing gold nanoparticles is left for a predetermined time after being wrapped as necessary (s14). The leaving time is determined while checking the change in the softness of the hair depending on the hair quality, the strength of the reducing power of the first agent, the degree of damage received by the hair, and the like. Generally, it is preferably left for 5 to 30 minutes, more preferably 10 to 30 minutes, and particularly preferably about 15 to 20 minutes. Then, after applying the hair treatment liquid containing the first agent and gold nanoparticles as described above to the hair and leaving it for a predetermined time, if necessary, the first agent is rinsed off by performing water washing or shampooing (s15). Then, a second agent containing an oxidizing agent is applied to the hair wound around the rod (s16) and left for a predetermined time (s17). The second agent is the same as that described in the hair straightening and correcting treatment method described in the first embodiment. After applying the second agent to the hair and leaving it for a predetermined time, a disulfide bond is re-formed in the hair wound around the rod (s17). Then, after leaving it for a predetermined time, the rod is removed from the hair wound around the rod (s18). The effect of applying the hair treatment liquid containing gold nanoparticles in the permanent wave treatment method of this embodiment is also remarkably recognized in the retention of the wave ridge feeling when the rod is removed. Regarding the retention of the ridge feeling when the rod is removed from the hair wound around the rod, when the hair treatment liquid containing gold nanoparticles is not applied, as shown in Fig. 3(a), a phenomenon of "drooping" in which the curl becomes loose due to gravity is likely to occur. By applying the hair treatment liquid containing gold nanoparticles in the permanent wave treatment method of this embodiment, as shown in Fig. 3(b), it was confirmed that the hair is maintained firm and "hard to droop", and the ridge feeling is firmly retained. Then, the hair is washed (s19). In washing, shampooing and treatment are performed if necessary. Then, after washing, drying such as towel drying and ventilation drying is performed (s20). Through such steps, the permanent wave treatment of this embodiment that suppresses the generation of split ends and frayed hair is applied. In this embodiment, by applying a hair treatment liquid containing gold nanoparticles before, during, and immediately after applying the first agent, the reaction by the first agent can be moderated and rapid cleavage of disulfide bonds can be suppressed. Therefore, it is possible to suppress the occurrence of unfavorable reactions promptly and it is preferable from the viewpoint that it becomes easier to control the damage to the hair. Note that the hair treatment liquid containing gold nanoparticles may be further applied at any step until the end of the treatment and also after the treatment. Further, it may be applied not once but in multiple portions. The redox reaction in the permanent wave treatment does not end immediately after the treatment but progresses for several days even after the treatment. Therefore, the effect of suppressing unfavorable redox reactions is exhibited at any time before, during, and after the treatment. [Third Embodiment] In the second embodiment, as a representative example of the permanent wave treatment, a general permanent wave treatment was described. When stronger shaping is required such as strong curls or shape memory curls, a so-called digital perm, which includes a step of heating with a heater provided on a rod while the hair is curled, may be employed. Hereinafter, a permanent wave treatment method using a digital perm will be described. In the permanent wave treatment method of this embodiment, first, a hair treatment liquid containing gold nanoparticles is spray-applied evenly to the hair. Then, a first agent containing a reducing agent is applied to the hair coated with the hair treatment liquid, and left for a predetermined time to reduce the disulfide bonds and eliminate the crosslinked structure. At this time, it is preferable to leave it for 5 to 20 minutes, and more preferably about 10 to 15 minutes while monitoring the softness of the hair so that it becomes moderately soft. After leaving for the predetermined time, the first agent is rinsed off. It is also preferable to spray-apply a hair treatment liquid containing gold nanoparticles to the wet hair after rinsing off the first agent. Then, the first agent is rinsed away, and the wet hair coated with the hair treatment liquid containing uniformly dispersed gold nanoparticles is wound around a plurality of rods equipped with heaters for heating. Then, the electrodes of each rod are connected to a controller, and heating is performed for a predetermined time by controlling the temperature of the controller. The set temperature for heating is preferably 40 to 60°C, more preferably 45 to 55°C. Also, the heating time is preferably about 5 to 25 minutes, more preferably about 10 to 20 minutes. After heating, the rods are removed from the hair. Then, a hair treatment liquid containing gold nanoparticles and, if necessary, other treatment agents are applied to the hair. Then, a second agent is applied to the hair and left for a predetermined time to oxidize the thiol groups to form a cross-linked structure. The leaving time is preferably 0 to 10 minutes, more preferably about 5 to 10 minutes. After leaving, the second agent is rinsed away. After rinsing away the second agent, it is preferable to further apply a hair treatment liquid containing gold nanoparticles. Then, the hair is styled by blowing it while drying for finishing. As the permanent wave treatment method of the present embodiment, even when a hot permanent such as a digital perm is adopted, it has been recognized that split ends and broken hairs are suppressed, the hair maintains firmness and becomes "hard to fall out", and the ridge feeling is firmly maintained. Hereinafter, the present invention will be described in more detail with reference to examples. The scope of the present invention is not limited by these examples in any way. (Example 1) The first agent was applied while combing to the hair of a female monitor, which had slightly damaged and somewhat prominent split ends and was curly hair. The first agent was prepared in a formulation with a pH of 4.5 containing 6% by mass of ammonium thioglycolate in a cream base mainly composed of cetanol. Then, while checking the softness of the hair, it was left to stand naturally for about 20 minutes. Then, it was shampooed. Then, a stock solution of gold nanocolloid (gold content concentration: 0.005% by mass) was sprayed uniformly over the entire wet hair after shampooing. Then, the hair was straightened by combing with a comb. The combability at this time was judged according to the following criteria. (Combing property) A: There was almost no feeling of the comb getting caught due to hair entanglement, and the combing was extremely good. B: Although slightly inferior to A, there was little catching of the comb due to hair entanglement, and the combing was good. C: The combing was so bad that the comb often got caught due to hair entanglement, and it was impossible to comb without slowly moving the comb. When the combing property was judged, it was A. Then, the hair after combing was dried with a hair dryer. Then, the dried hair was straightened by stretching it with a hair iron set at 160 °C. Then, the second agent was applied to the straightened hair, left to stand naturally for about 10 minutes, washed with water, and further dried with a hair dryer. The second agent used was prepared with a formulation in which 6% by mass of hydrogen peroxide solution was adjusted to about 1.5% by mass with water. In this way, hair straightening was performed. Then, the obtained hair was judged according to the following criteria. (Occurrence of split ends or frizzy hair) A: Almost no split ends or frizzy hair were observed even with careful observation. B: Split ends or frizzy hair occurred to the extent that they could be recognized when carefully observed. C: Split ends and frizzy hair occurred to the extent that they were significantly recognizable in appearance. The obtained hair had no occurrence of frizzy hair or split ends and was corrected to natural straight hair. Also, even one week after the treatment, there was no occurrence of frizzy hair. The results are shown in Table 1 below. (Example 2) On the hair of another monitor female with frizzy and curly hair that had received even more damage than the female monitor in Example 1, hair shrinkage correction was performed in the same manner as in Example 1, except that the standing time after applying the first agent was changed to about 30 minutes. When combing, as in Example 1, the combing was extremely good, and the combability was judged as A. Also, the resulting hair was corrected to natural straight hair without the occurrence of split ends or broken hairs. Also, even one week after the treatment, there was no occurrence of split ends. (Example 3) On another monitor female with hair that had even more damage than the female monitor in Example 2 and prominent frizzy hair, hair shrinkage correction was performed in the same manner as in Example 2. When combing, as in Example 2, the combing was extremely good, and the combability was judged as A. Also, the resulting hair was corrected to natural straight hair without the occurrence of split ends or broken hairs. Also, even one week after the treatment, there was no occurrence of split ends. (Example 4) On another monitor female with hair that had received damage comparable to that of the female monitor in Example 2, hair shrinkage correction was performed in the same manner as in Example 2, except that instead of applying the stock solution of gold nanoparticles, a 10-fold diluted gold nanoparticle solution was applied. As in Example 2, the combing was extremely good, and the combability was judged as A. Also, the resulting hair was corrected to natural straight hair without the occurrence of split ends or broken hairs. Also, even one week after the treatment, there was no occurrence of split ends. (Example 5) Another female monitor with hair damaged to the same extent as that of the female monitor in Example 2 was given a hair straightening treatment in the same manner as in Example 2, except that instead of applying the stock solution of gold nanoparticles, a 100-fold diluted gold nanoparticle solution was applied. When combing, the result was slightly inferior to that of Example 4 but still good, with few catches of the comb due to tangles, and the combability was rated as B. Also, the resulting hair was corrected to natural straight hair without the occurrence of split ends or broken hair. However, a slight tendency for split ends to occur was observed one week after the treatment. (Comparative Example 1) Another female monitor with hair damaged to the same extent as that of the female monitor in Example 1 was given a hair straightening treatment in the same manner as in Example 1, except that the step of applying gold nanoparticles was omitted. At this time, the combing result was poor, and the combability was rated as C. Also, split ends occurred at the nape of the resulting hair. Also, the hair was corrected to straight hair with some remaining hair shrinkage. (Comparative Example 2) Another female monitor with hair damaged to the same extent as that of the female monitor in Example 2 was given a hair straightening treatment in the same manner as in Example 2, except that instead of applying gold nanoparticles, platinum nanoparticles (platinum content concentration 0.005% by mass) were applied undiluted. At this time, the combing result was poor, and the combability was rated as C. Split ends occurred at the nape of the resulting hair. In the above examples, after applying the first agent, it is left for 20 to 30 minutes. This is set to be slightly longer than the standing time in normal hair straightening treatments for evaluation purposes. From the results of the examples, the following can be understood. In the monitors of the women in Examples 1 to 3 where the stock solution of gold nanoparticles was sprayed and in Example 4 where the gold nanoparticles diluted 10-fold from the stock solution of gold nanoparticles were sprayed, regardless of the strength of the damage and the standing time, it was possible to finish with natural straight hair without the occurrence of frizzy hair or split ends. Also, the combability was good. On the other hand, as shown in Example 5, when the concentration of gold nanoparticles was low, frizzy hair tended to occur after the treatment. On the other hand, in the monitor of the woman in Comparative Example 1 where the strength of the damage and the standing time were about the same as in Example 1 and gold nanoparticles were not sprayed, frizzy hair occurred at the nape. Also, the combability was poor. On the other hand, in the monitor of the woman in Comparative Example 2 where the strength of the damage and the standing time were about the same as in Example 2 and platinum nanoparticles were sprayed instead of gold nanoparticles, frizzy hair also occurred at the nape. Also, no improvement in combability was observed. (Example 6) The stock solution of gold nanoparticles (gold content concentration: 0.005% by mass) was evenly sprayed over the entire hair of the monitored woman, which had slightly large damaged branched hairs with a history of hair straightening treatment and was somewhat noticeable. Then, after winding the hair coated with gold nanoparticles around a rod, the first agent was applied. Further, after spraying the stock solution of gold nanoparticles, it was left standing for 15 minutes. The first agent was prepared with a formulation having a pH of 4.5 containing 6% by mass of ammonium thioglycolate in a cream base mainly composed of cetanol. Then, the first agent was rinsed off by washing the hair wound around the rod with hot water. Then, the second agent was applied to the wet hair after rinsing, and it was left to stand naturally for about 10 minutes while checking the curling condition midway. Note that, as the second agent, a preparation prepared with a formulation in which 6 mass% hydrogen peroxide solution was adjusted to about 1.5 mass% with water was used. Then, the rod was removed from the hair. Then, the second agent was removed by shampooing the hair. Then, the hair was blow-dried while drying with a hair dryer. Then, the occurrence of split ends or frizzy hair was determined according to the same criteria as in Example 1. Also, according to the following criteria, the shaping feeling and the finished feeling by the operator immediately after removing the rod were determined. (Shaping feeling by the operator immediately after removing the rod) A: The hair was firmly shaped with strong firmness and curl. B: The hair had no firmness, and the hair hung down due to gravity and the curl was loose. (Finished feeling) A: A firm curl with a high ridge feeling and elasticity as intended from the diameter of the rod was obtained. B: A curl as intended from the diameter of the rod was not obtained, and a loose curl with a low ridge feeling was obtained. According to the determination by the operator immediately after removing the rod, the hair was firmly shaped with strong firmness and curl. Also, there was no occurrence of frizzy hair or split ends in the finished hair, and a permanent wave with a high ridge feeling was shaped. The results are summarized in Table 2 below. (Example 7) A permanent wave treatment was performed in the same manner as in Example 6 on another female monitor having hair damaged to the same extent as the female monitor in Example 6, except that instead of applying the stock solution of gold nanoparticles, a 10-fold diluted gold nanoparticle solution was applied. The results are shown in Table 2. (Example 8) Another female monitor with hair damaged to the same extent as that of the female monitor in Example 6 was given a permanent wave treatment in the same manner as in Example 6, except that instead of applying the undiluted solution of gold nanocolloid, a gold nanocolloid diluted 100-fold was applied. The results are shown in Table 2. (Comparative Example 3) Another female monitor with hair damaged to the same extent as that of the female monitor in Example 6 was given a permanent wave treatment in the same manner as in Example 6, except that the step of applying the gold nanocolloid was omitted. The results are shown in Table 2. (Comparative Example 4) Another female monitor with hair damaged to the same extent as that of the female monitor in Example 6 was given a permanent wave treatment in the same manner as in Example 6, except that instead of applying the gold nanocolloid, a platinum nanocolloid (platinum content concentration: 0.005% by mass) was applied undiluted. The results are shown in Table 2. From the results of Examples 6 to 8, Comparative Example 3, and Comparative Example 4, the following can be understood. In the female monitors of Example 6 where the undiluted solution of gold nanocolloid was sprayed and Example 7 where a gold nanocolloid diluted 10-fold was sprayed, no split ends or frizzy hairs were observed, and the curls were firmly shaped. Also, the operator determined that the hair had a strong firmness immediately after removing the rod and the curls did not droop due to gravity. On the other hand, as shown in Example 8, when the concentration of the gold nanocolloid was low, the effect was somewhat insufficient. On the other hand, in the female monitor of Comparative Example 3 where the gold nanocolloid was not sprayed and the female monitor of Comparative Example 4 where the platinum nanocolloid was sprayed instead of the gold nanocolloid, split ends and frizzy hairs occurred, and a loose curl that was difficult to develop a ridge feeling was shaped. Also, the operator determined that the hair had no firmness immediately after removing the rod and the curls were drooping due to gravity. (Example 9) The entire hair of the woman on the monitor, where the damaged and somewhat prominent split ends were slightly noticeable, was evenly sprayed with a hair treatment liquid that was a stock solution of gold nanoparticles (gold content concentration: 0.005% by mass). Then, the first agent was applied to the hair onto which the hair treatment liquid had been applied. Furthermore, after spraying the hair treatment liquid, it was left for 15 minutes. The first agent was prepared in a formulation with a pH of 4.5 containing 6% by mass of ammonium thioglycolate in a cream base mainly composed of cetanol. Then, the first agent was rinsed off by washing the hair with hot water. And further, the hair treatment liquid was sprayed again. Then, while rinsing off the first agent and with the hair in a wet state where the hair treatment liquid had been evenly applied, the second agent was applied. The second agent used was prepared in a formulation where 6% by mass of hydrogen peroxide solution was adjusted to approximately 1.5% by mass with water. Then, the hair onto which the second agent had been applied was wound around a plurality of rods equipped with a heater for heating. And the electrodes of each rod were connected to a controller set at 45°C and heated for 20 minutes. After heating, the rods were removed from the hair and the second agent was rinsed off. Then, the hair was blow-dried while being dried with a hair dryer. And, based on the same criteria as in Example 6, the shaping feeling and the finished feeling by the operator immediately after removing the rods were judged. (Shaping feeling by the operator immediately after removing the rods) A: The hair had a strong firmness and the curls were firmly shaped. B: The hair had no firmness, the hair hung down due to gravity, and the curls were loose. (Finished feeling) A: From the diameter of the rod, a firm curl with a high ridge feeling and the desired elasticity was obtained. B: From the diameter of the rod, the desired degree of curl was not obtained, and a loose curl with a low ridge feeling was obtained. According to the judgment of the operator immediately after removing the rods, the hair had a strong firmness and the curls were firmly shaped. Also, there was no occurrence of frizzy hair or split ends in the finished hair, and a permanent wave with a high ridge feeling was shaped. The results are summarized in Table 3 below. (Example 10) To another female monitor having hair damaged to the same extent as that of the female monitor in Example 9, a permanent wave treatment was performed in the same manner as in Example 6, except that a 10-fold diluted gold nanoparticle solution was applied instead of the undiluted gold nanoparticle solution. The results are shown in Table 3. (Example 11) To another female monitor having hair damaged to the same extent as that of the female monitor in Example 9, a permanent wave treatment was performed in the same manner as in Example 6, except that a 100-fold diluted gold nanoparticle solution was applied instead of the undiluted gold nanoparticle solution. The results are shown in Table 3. (Comparative Example 5) To another female monitor having hair damaged to the same extent as that of the female monitor in Example 9, a permanent wave treatment was performed in the same manner as in Example 6, except that the step of applying gold nanoparticles was omitted. The results are shown in Table 3. (Comparative Example 6) To another female monitor having hair damaged to the same extent as that of the female monitor in Example 9, a permanent wave treatment was performed in the same manner as in Example 6, except that platinum nanoparticles (platinum content concentration: 0.005% by mass) were applied undiluted instead of gold nanoparticles. The results are shown in Table 3. According to the present invention, in hair treatments such as hair straightening treatments and permanent wave treatments, it is possible to significantly reduce the manifestation of damage caused during the treatment.

Claims

1. A method for hair shaping treatment, comprising at least the steps of: applying a first agent containing a reducing agent to hair and leaving it for a predetermined time; rinsing off the first agent applied to the hair; applying a second agent containing an oxidizing agent to the hair and leaving it for a predetermined time; and rinsing off the second agent, further comprising the step of applying a hair treatment liquid containing gold nanoparticles to the hair.

2. The method for hair shaping treatment according to claim 1, wherein the concentration of gold nanoparticles in the hair treatment liquid is 0.0001% by mass or more.

3. The method for hair shaping treatment according to claim 1 or 2, wherein the hair treatment liquid further contains platinum nanoparticles.

4. The method for hair shaping treatment according to any one of claims 1 to 3, wherein the step of applying the hair treatment liquid to the hair is provided before applying the second agent.

5. The method for hair shaping treatment according to any one of claims 1 to 4, wherein the first agent has a pH of 5 to 8.

6. The method for hair shaping treatment is a method for hair straightening treatment, further comprising the step of straightening the hair while heating the hair after rinsing off the first agent, according to any one of claims 1 to 5.

7. The method for hair shaping treatment according to claim 6, further comprising the step of drying the hair after rinsing off the first agent and combing the hair while spray-applying the hair treatment liquid to the hair.

8. The method for hair shaping treatment according to claim 6 or 7, wherein the heating is performed with a hair iron set at 110 to 180°C.

9. The method for hair shaping treatment is a permanent wave treatment method, further comprising the step of shaping the hair by winding it around a rod, according to any one of claims 6 to 8.

10. The method for hair shaping treatment according to claim 9, further comprising the step of heating the rod to 50°C or higher with the hair wound around the rod.

11. A hair treatment liquid for hair shaping treatment, which is a hair treatment liquid applied to hair in a hair shaping treatment that is a hair straightening treatment or a permanent wave treatment, characterized by containing gold nanoparticles.

12. The hair treatment liquid for hair shaping treatment according to claim 11, comprising the gold nanoparticles in an amount of 0.0001% by mass or more.

13. The hair treatment liquid for hair shaping treatment according to claim 11 or 12, further comprising platinum nanoparticles.

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