Hair composition and hair treatment method

Abstract

To provide a hair composition that improves the properties of damaged hair. To provide a method for performing hair treatment using a hair composition that improves the properties of damaged hair. [Solution] A hair composition comprising the following components (A) and (B). (A) At least one iridoid compound selected from iridoids and secoiridoids. (B) Monovalent or polyhydric alcohols with 6 or fewer carbon atoms.

Description

Technical Field

[0001] The present invention relates to a hair composition and a hair treatment method.

Background Art

[0002] Due to physical treatments such as brushing, hair drying, and using a hot iron, the texture and luster of hair may deteriorate. In addition, due to chemical treatments such as hair coloring and permanent waving, the outflow of keratin protein inside the hair may occur, and hair elasticity and hair strength may be lost. For hair damaged by physical or chemical treatments, treatments with various protective agents and repair agents have been proposed.

[0003] Patent Document 1 discloses a hair composition containing a specific hydroxyl group-containing compound containing catechol or hydroquinone. In the examples of Patent Document 1, it is shown that when a composition containing components such as catechol, hydroquinone, and chicoric acid is applied to hair, the breaking strength of the hair is improved. The breaking strength of hair indicates the difficulty of hair breakage and is an index of hair characteristics.

[0004] Patent Document 2 discloses a hair treatment agent containing an iridoid compound and an amino group-containing compound, and a method for repairing damaged hair by treating damaged hair with such a hair treatment agent. As the iridoid compound, genipin, genipinic acid, geniposide, and secoiridoid A are used in the examples of Patent Document 2. Also, in the examples of Patent Document 2, as a "non-damage test", after treating a human hair sample with a hair treatment agent, the breaking strength is measured by a tensile strength tester, and when the breaking strength is almost the same as that of untreated hair, it is evaluated as non-damaged (〇).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

[0006] With the increasing diversity of hair coloring, hair treatments that place a great burden on the hair are sometimes performed, such as bleaching the hair multiple times before dyeing it. Against this backdrop, there is a need for hair treatment agents that can care for hair damaged by hair coloring and other treatments. In view of this situation, one of the objectives of the present invention is to provide a hair composition that can improve the properties of damaged hair (improvement of hair strength or suppression of the decrease in hair strength, improvement of cuticle elasticity). Another objective of the present invention is to provide a method for performing hair treatment using a hair composition that can improve the properties of damaged hair. [Means for solving the problem]

[0007] This disclosure includes the following inventions [1] to [7]. [1] A hair composition comprising the following ingredients (A) and (B). (A) At least one iridoid compound selected from iridoids and secoiridoids. (B) Monovalent or polyhydric alcohols with 6 or fewer carbon atoms.

[0008] [2] The hair composition according to [1], wherein the amount of component (A) is less than or equal to the amount of component (B). [3] The hair composition according to [1] or [2], wherein the amount of component (B) is 0.05% by mass or more. [4] A hair composition according to any one of [1] to [3], comprising at least 1,3-butylene glycol as component (B).

[0009] A hair treatment method characterized by using a hair composition described in any one of items [5][1] to [4]. [6] (I) The step of applying the hair composition described in any one of items [1] to [4] to the hair, (II) A hair treatment method according to [5], comprising the step of leaving the hair to which the hair composition has been applied at a temperature of 20°C or higher and 80°C or lower for 20 minutes or less. [7] The hair treatment method according to [6], wherein step (II) is a step of leaving the hair at a temperature without heating for 20 minutes or less. [Effects of the Invention]

[0010] The hair composition according to this disclosure provides a hair composition that can improve the properties of damaged hair, and a hair treatment method using such a hair composition. [Modes for carrying out the invention]

[0011] The hair composition relating to this disclosure is a hair composition comprising the following components (A) and (B). (A) At least one iridoid compound selected from iridoids and secoiridoids. (B) Monovalent or polyhydric alcohols with 6 or fewer carbon atoms.

[0012] While hair treatment agents containing iridoid compounds are known (e.g., Patent Document 2), their effect on improving hair properties in damaged hair such as bleached hair, and the composition suitable for obtaining this effect, have not been investigated. Furthermore, many shampoos and conditioners currently on the market are weakly acidic, and there is a need for a hair treatment agent that is effective in a wide pH range including weak acidity. Moreover, from the standpoint of ease of use, there is a need for a hair treatment agent that does not require heating or prolonged waiting during application. According to the hair composition of this disclosure, an effect can be obtained in a wide pH range including the acidic range, the treatment time is short, and the effect of improving hair properties can be obtained even without heating.

[0013] [Specific examples of embodiments] The hair composition according to the present disclosure will be described more specifically below. In this specification, unless otherwise specified, "A~B" representing a numerical range means "A or more and B or less".

[0014] <Hair composition> The hair composition according to the present disclosure is a composition in which the component (A) and the component (B) described in detail below are blended. The hair composition according to the present disclosure is typically blended with water, and the blending amount of water in the hair composition is, for example, 60% by mass or more.

[0015] The pH of the hair composition according to the present disclosure is not particularly limited, and it may be acidic (for example, pH 2 or more and less than 7, pH 4 or more and less than 7, pH 4 or more and less than 6), neutral (pH 7 or more and less than 8), or alkaline (for example, pH 8 or more and less than 12, pH 9 or more and less than 11). Usually, it is preferably pH 4 or more and 10 or less. The hair treatment agent according to the present disclosure is considered to exhibit an effect of improving hair properties when the component (A) and the component (B) are combined, and this effect is considered to be obtained regardless of the pH range.

[0016] <Component (A)> The hair composition according to the present disclosure contains at least one iridoid compound selected from iridoids and secoiridoids as the component (A). An iridoid is a compound having a condensed ring structure of a hetero 6-membered ring having oxygen and a 5-membered carbon ring, and a secoiridoid is a compound in which the 5-membered ring of an iridoid is oxidatively cleaved (hereinafter, iridoids and secoiridoids may be collectively referred to as iridoid compounds).

[0017] The iridoid compound blended in the composition according to the present disclosure may be one or more selected from known iridoid compounds. Examples of iridoids include, for example, iridoids represented by the following general formula (1).

[0018]

Chemical formula

[0019] Specifically, the alkyl groups represented by A1 and A2 in the formula (1) may be a methyl group, an ethyl group, an n-propyl group, a butyl group, etc. Specifically, examples of the salt-forming cations represented by M in the formula (1) include cations of alkali metals, alkaline earth metals, alkanolamines, or basic amino acids.

[0020] Specific examples of iridoid compounds include iridoids such as genipin, aucubin, geniposide, geniposidic acid, loganic acid, loganin, oleuropein, and gentiopicroside, and one or more of these can be included. Further, examples of secoiridoids include swertiamarin, gentiopicroside, etc., and one or more of these can be included. It may contain iridoids and secoiridoids.

[0021] Genipin is a compound obtained by hydrolyzing an iridoid glycoside (geniposide) contained in the fruit extract of Gardenia jasminoides or the extract of Genipa americana with β-glucosidase, and a plant extract can also be blended as the (A) component. As the plant extract, a component derived from Gardenia jasminoides used as a cosmetic raw material can be used. For example, raw materials that can be obtained from the market such as Gardenia jasminoides concentrated extract, Gardenia jasminoides fruit extract, Gardenia jasminoides blue, and Gardenia jasminoides extract can be used.

[0022] The amount of component (A) in the hair composition is not particularly limited, but is preferably 0.001% by mass or more and less than 3.0% by mass, more preferably 0.01% by mass or more and less than 2% by mass, more preferably 0.05% by mass or more and less than 1.5% by mass, and even more preferably 0.1% by mass or more and less than 0.1% by mass. An amount of 0.001% by mass or more is suitable for improving the physical properties of hair, and an amount of less than 3.0% by mass is suitable for reducing costs.

[0023] (A) When component (A) is included in a plant extract, the amount of plant extract included is not particularly limited relative to the total hair composition, but is preferably 0.01% by mass or more and less than 30% by mass, more preferably 0.1% by mass or more and less than 20% by mass, more preferably 0.5% by mass or more and less than 15% by mass, and even more preferably 0.1% by mass or more and less than 10% by mass. An amount of 0.1% by mass or more is suitable for improving hair properties, and an amount of less than 20% by mass is suitable for reducing costs.

[0024] While not strictly bound by theory, component (A) is considered an effective ingredient for improving hair properties. It is believed that component (A) penetrates the hair and contributes to improving hair properties by acting as a crosslinking agent for proteins and collagen. This improvement in hair properties includes an increase in the breaking strength of the hair and an increase in the elastic modulus of the cuticle. An increase in the breaking strength of the hair makes it less prone to breakage and split ends, and an increase in the elastic modulus of the cuticle increases the health of the cuticle, making it less likely to peel off during washing, while also providing a firmer, more resilient feel.

[0025] <(B) component> The hair composition according to this disclosure contains a monohydric or polyhydric alcohol with 6 or fewer carbon atoms as component (B). Although not bound by theory, it is believed that component (B) functions as a penetrating agent and assists in the penetration of component (A) into the hair, thereby making it easier for component (A) to exert its effects.

[0026] Examples of monohydric alcohols with 6 or fewer carbon atoms include ethanol, 1-propanol, isopropanol, n-butanol, pentanol, and hexanol. Examples of polyhydric alcohols with 6 or fewer carbon atoms include dihydric alcohols such as ethylene glycol, propylene glycol (1,2-propanediol), propanediol (1,3-propanediol), 1,2-butylene glycol, 1,3-butylene glycol, and dipropylene glycol. Examples of trihydric alcohols include glycerin and sorbitol. An example of a tetrahydric alcohol is mannitol.

[0027] Among these, it is preferable that component (B) contains a polyhydric alcohol having 6 or fewer carbon atoms, and in particular, it is preferable that it contains one or more of 1,3-butylene glycol, propylene glycol, and sorbitol. In particular, it is preferable that it contains 1,3-butylene glycol. It is preferable that the composition according to this disclosure contains at least 1,3-butylene glycol.

[0028] (B) may contain two or more types, and it is also preferable to include a combination of a monohydric alcohol having 6 or fewer carbon atoms and a polyhydric alcohol having 6 or fewer carbon atoms. More specifically, it may be a combination of ethanol and a polyhydric alcohol, and (B) may include ethanol and 1,3-butylene glycol, ethanol and propylene glycol, or ethanol and sorbitol.

[0029] The amount of component (B) in the hair composition is not particularly limited, but is preferably 0.05% by mass or more and less than 20% by mass, more preferably 0.05% by mass or more and less than 8% by mass, more preferably 0.05% by mass or more and less than 6% by mass, and even more preferably 0.05% by mass or more and less than 4% by mass. If it is 0.05% by mass or more, a function that improves hair properties can be obtained. If it is less than 4% by mass, manufacturing costs can be reduced.

[0030] (B) When component is a polyhydric alcohol, the amount of polyhydric alcohol blended into the hair composition is not particularly limited, but 0.05% by mass or more and less than 10% by mass is good, 0.05% by mass or more and less than 8% by mass is preferred, 0.05% by mass or more and less than 6% by mass is more preferred, and 0.05% by mass or more and less than 4% by mass is even more preferred. If it is 0.05% by mass or more, a function that improves hair properties can be obtained. If it is less than 4% by mass, the manufacturing cost can be reduced.

[0031] The amount of component (A) is preferably less than or equal to the amount of component (B). Although not particularly limited, the ratio of component (A) to component (B) may be between 1:1 and 1:20000.

[0032] (B) When the component contains a polyhydric alcohol with 6 or fewer carbon atoms, the ratio of the amount of component (A) to the amount of polyhydric alcohol is preferably 1:1 to 1:10000. Component (B) is thought to function as a penetrating agent that allows component (A) to penetrate the hair, and the presence of a high-quality alcohol is thought to make it easier to obtain the hair property-improving effect of component (A).

[0033] <Other ingredients> The hair composition according to this disclosure may contain other components in addition to components (A) and (B). The hair composition according to this disclosure may also contain components known as components in hair compositions, insofar as it has the effects according to this disclosure. Examples of optional components include higher alcohols, cationic surfactants, anionic surfactants, nonionic surfactants, polyhydric alcohols with more than 6 carbon atoms, sugars, ester oils, fats and oils, fatty acids, hydrocarbons, waxes, silicones, polymer compounds, amino acids, fragrances, preservatives, etc.

[0034] When a higher alcohol and a cationic surfactant are incorporated into the hair composition according to this disclosure, the higher alcohol may have 12 to 22 carbon atoms. Examples of higher alcohols include linear saturated alcohols such as cetyl alcohol, stearyl alcohol, and behenyl alcohol; and branched saturated alcohols such as hexyldecanol, octyldodecanol, isostearyl alcohol, and tetradecyloctadecanol. The amount of higher alcohol incorporated is not particularly limited, but may be, for example, 1% to 10% by mass. Examples of cationic surfactants include fatty acid amidoamine salts, Arcover-type tertiary amine salts, long-chain alkyltrimethylammonium salts, dilong-chain alkyldimethylammonium salts, and monoalkyl ether-type quaternary ammonium salts (wherein "long-chain alkyl" is preferably an alkyl group having 12 to 22 carbon atoms). The amount of cationic surfactant incorporated is not particularly limited, but may be, for example, 1% to 5% by mass.

[0035] <Hair treatment method> The hair treatment method according to this disclosure is a method performed using the hair composition described above. The method is similar to known hair treatment methods and is not particularly limited. Examples of the hair treatment method according to this disclosure include conditioners, treatments (e.g., leave-in treatments, rinse-off treatments, styling and application treatments, components of multi-component treatments, treatments for pre-perming, treatments for post-perming, treatments for pre-coloring, treatments for post-coloring, treatments for pre-bleaching, treatments for post-bleaching), and styling products.

[0036] The specific procedure for the treatment may involve applying the hair composition according to this disclosure to the hair and then rinsing it off with water or leaving it in. The hair to be treated by the hair treatment method is not particularly limited. Since the physical properties of hair deteriorate due to physical treatment (e.g., brushing) or chemical treatment (e.g., oxidative dyeing, hair straightening, permanent wave treatment), such hair may be the target of the hair treatment method according to this disclosure.

[0037] The temperature at which the hair treatment is performed is not particularly limited; it may be performed by heating at 20°C to 80°C, or without heating. The hair treatment method using the composition according to this disclosure is effective even at room temperature (around 25°C), and it has been confirmed that it can improve hair properties even without heating such as a dryer or heat treatment. Furthermore, the time for the hair treatment is not particularly limited and may range from 5 minutes to 12 hours. In particular, it has been confirmed that the method using the composition according to this disclosure can improve hair properties even with a short treatment time. The time for leaving the hair to which the composition according to this disclosure is applied (coating, spraying, etc.) is 20 minutes or less, effects can be obtained even with 10 minutes or less, and effects can be obtained even with 5 minutes or less.

[0038] The preferred formulation for a hair composition is one that is easy to apply to and blend into the hair, and can be liquid, emulsion, lotion, cream, foam, or mist. The viscosity of the hair composition can be arbitrarily selected depending on the application, but for example, the viscosity measured at 25°C for 60 seconds using a B-type viscometer may be 80,000 mPa·s or less, and preferably 50,000 mPa·s or less.

[0039] [Examples] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0040] Hair treatment was performed using the hair compositions of the examples and comparative examples, and the work of breaking and cuticle modulus were measured as indicators of hair properties. Details are as follows.

[0041] 1. Preparation of hair composition Hair compositions were prepared to match the formulations and pH levels shown in Tables 1 to 12. The hair compositions were obtained by thoroughly mixing the components shown in each table to prepare a mixed solution. Each composition was then mixed with a buffer solution of the specified pH to achieve a total volume of 100% by mass. The components used are as follows:

[0042] [Ingredients (A)] Genipin (manufactured by Tokyo Chemical Industry Co., Ltd. (reagent)) Geniposide (manufactured by Tokyo Chemical Industry Co., Ltd. (reagent)) Aucubin (manufactured by Tokyo Chemical Industry Co., Ltd. (reagent)) Oleuropein (manufactured by Tokyo Chemical Industry Co., Ltd. (reagent)) Gardenia extract (manufactured by Koei Kogyo Co., Ltd.) Gardenia concentrated extract (manufactured by Koei Kogyo Co., Ltd.) Falcorex Gardenia B (manufactured by Ichimaru Falcos Co., Ltd.) Swertiamarin (manufactured by Kishida Chemical Co., Ltd.)

[0043] [Component (B)] ethanol 1,3-Butylene glycol (1,3BG) Isopropyl alcohol (IPA) Glycerin 1-Propanol Propylene glycol Sorbitol [Hydrogen compounds that do not fall under component (B)] PEG-200

[0044] [Buffer] 0.1M citrate buffer (pH 3) 0.1M phosphate buffer (pH 6, pH 8) 0.1M carbonate buffer (pH 10)

[0045] 2. Processing method • Hair to be treated Using Japanese female hair obtained from a hair salon, bleached hair was created using the following method. Powder bleach (Ordeve Addicthy High Bleach, manufactured by Milbon Corporation) and hair color (Ordeve Addicthy Oxidant 6.0, manufactured by Milbon Corporation) were mixed in a weight ratio of 1:2 and applied to the hair in a bath ratio of 1:4. The mixture was left to stand at room temperature for 30 minutes. After that, the hair was rinsed with running water, then massaged with a 1% sodium dodecyl sulfate aqueous solution, and rinsed again with running water. The hair was then towel-dried and completely dried with a hairdryer. Bleached hair was obtained by repeating this series of operations three times on the same hair. In the table below, bleached hair that was bleached simultaneously from human hair samples of the same lot was used as the hair to be treated. • Hair treatment methods Compositions having the compositions shown in each table were applied to bleached hair in a bath ratio of 1:1 and left at a predetermined temperature for a predetermined time. After leaving, the hair was rinsed with running water, then rubbed with a 1% sodium dodecyl sulfate aqueous solution, and then rinsed again with running water. After that, the hair was towel-dried and completely dried with a hairdryer. The resulting hair was used as treated hair.

[0046] 3. Hair evaluation (1) Hair strength Ten strands of hair were randomly selected from the treated hair, and their diameters (long and short) were measured perpendicular to the fiber axis using a laser-type external shape measuring device. Brass clamps were also attached to the selected hairs to prepare samples for tensile testing. These samples were then mounted on an automated tensile testing machine (Dia-Stron) and stretched at a constant speed of 3 mm / min until the hair broke. The work of fracture (J / m²) was calculated from the elongation, stress, and hair diameter at the time of fracture. 3 The following values ​​were calculated: The same test was repeated 10 times on the same treated hair, and the average of the obtained values ​​was calculated. Furthermore, the ratio (%) of the work of breakage of treated hair to the work of breakage of untreated bleached hair was calculated. Breaking work refers to the amount of energy per unit volume required for hair to break due to stretching; the higher this value, the more difficult the hair is to break.

[0047] (2) Cuticle elastic modulus Method for measuring the elastic modulus of hair cuticles using nanoindentation with atomic force microscopy (AFM) A commercially available silicon AFM probe, NCHV (manufactured by Bruker), was used as the probe for measurement. The probe was attached to an AFM device (MultiMode V, manufactured by Bruker), and measurements were performed in tapping mode. The measurement conditions were a scan rate of 1 Hz, and the spring constant and sensitivity of the probe were calibrated using calibration samples VGRP-15M (manufactured by Bruker) and PS-LDPE-12M (manufactured by Bruker) after each measurement. An arbitrary 10 × 10 μm rectangular area of ​​the cuticle portion of a hair sample attached to the AFM measurement stage with double-sided tape was scanned with the probe. During scanning, the rectangular area was divided into 256 × 256 sections, and measurements were taken at each point. After scanning the entire area, the probe was pressed into 20 arbitrary points within the scanned area to a depth of 20 nm, and then unloaded. From the depth of indentation during unloading and the stress applied to the probe, Hertz's formula was used. * The modulus of elasticity was calculated using [a specific method / tool]. Furthermore, the health of the cuticle can be evaluated by measuring the cuticle elasticity modulus. Hair with a high cuticle elasticity modulus is less prone to cuticle peeling during washing and is less likely to suffer damage to the inside of the hair. *: H. Hertz, Journal fur die reine und angewandte Mathematik, 92, 156-171(1882)

[0048] 4.Results (1) Series 1 (Study of iridoid compounds) Table 1 summarizes the formulations, pH, treatment conditions, and evaluation results of the compositions for Examples 1-4 and Comparative Examples 1 and 2. In Comparative Example 1, the work of breaking was measured for untreated bleached hair that was not treated with the hair composition. The work of breaking (%) is the value when the work of breaking of untreated hair (Comparative Example 1) is set to 100%.

[0049] [Table 1]

[0050] As shown in Table 1, in all cases where genipin, geniposide, aucubin, and oleuropein were used as component (A), the work of breaking improved compared to untreated hair (Comparative Example 1). Comparative Example 2, which was treated with a hair composition that did not contain component (A), showed a lower work of breaking than Comparative Example 1.

[0051] (2) Series 2 (pH examination) Tables 2 and 3 summarize the formulations, pH, treatment conditions, and evaluation results of the compositions for Examples 5-12 and Comparative Examples 3 and 4. In Comparative Examples 3 and 4, the work of breaking was measured for untreated bleached hair that was not treated with the hair composition. The work of breaking (%) is the value when the work of breaking of untreated hair (Comparative Examples 3 and 4) is set to 100%.

[0052] [Table 2]

[0053] [Table 3]

[0054] As shown in Tables 2 and 3, in all cases where the pH of the composition was 3, 6, 8, and 10, the work of breaking was improved compared to untreated hair (Comparative Examples 3 and 4).

[0055] (3) Series 3 (Examination of the amount of component B to be included) Table 4 summarizes the formulations, pH, treatment conditions, and evaluation results of the compositions for Examples 13-18 and Comparative Example 5. In Comparative Example 5, the work of breaking was measured for untreated bleached hair that was not treated with the hair composition. The work of breaking (%) is the value when the work of breaking of untreated hair (Comparative Example 5) is set to 100%.

[0056] [Table 4]

[0057] As shown in Table 4, in all cases where the amount of component (B) was 10% to 14%, the work of breaking improved compared to untreated hair (Comparative Example 5). Furthermore, when component (B) included 1,3BG, an improvement in the work of breaking was obtained even with a 1,3BG content of 0.1%, and the effect was greatest when 1,3BG was present. Comparative Example 6, which did not contain component (A), had a lower work of breaking than untreated hair.

[0058] (4) Series 4 (Consideration of processing method) Tables 5 and 6 summarize the formulations, pH, treatment conditions, and evaluation results of the compositions for Examples 19-28 and Comparative Examples 6 and 7. In Comparative Examples 6 and 7, the work of breaking was measured for untreated bleached hair that was not treated with the hair composition. The work of breaking (%) is the value when the work of breaking of untreated hair (Comparative Examples 6 and 7) is set to 100%.

[0059] [Table 5]

[0060] [Table 6]

[0061] As shown in Table 5, the composition according to this disclosure was used to improve hair strength in all cases where the treatment time ranged from 5 minutes to 12 hours. Even with a treatment time of 5 minutes (Example 19), the effect of improving hair strength was confirmed, demonstrating that sufficient effects can be obtained even with short treatment times. Furthermore, as shown in Table 6, the composition according to this disclosure was used to improve hair strength in all cases where the treatment temperature ranged from 25°C to 80°C. It was confirmed that sufficient effects can be obtained even at room temperature (25°C) without heating.

[0062] (5) Series 5 (Study of iridoid compounds) Table 7 summarizes the formulations, pH, treatment conditions, and evaluation results of the compositions for Examples 29-31 and Comparative Example 8. Examples 30 and 31 are examples in which plant extracts were used as components containing iridoid compounds. The work of breaking (%) is the value when the work of breaking of untreated hair (Comparative Example 8) is set to 100%.

[0063] [Table 7]

[0064] As shown in Table 7, an improvement in hair strength was also obtained when plant extracts containing iridoid compounds were used as ingredients.

[0065] (6) Series 6 (Examination of component B) Table 8 summarizes the formulations, pH, treatment conditions, and evaluation results of the compositions for Examples 32-33 and Comparative Example 9. Examples 32 and 33 do not contain ethanol as component (B), and instead use 1,3-BG or isopropanol (IPA). The work of breaking (%) is the value when the work of breaking of untreated hair (Comparative Example 9) is set to 100%.

[0066] [Table 8]

[0067] As shown in Table 8, even when ethanol was omitted and 1% 1,3-BG or isopropanol (IPA) was included, the effect of improving hair strength was obtained.

[0068] (7) Series 7 (Examination of the amount of component A) Table 9 summarizes the formulations, pH, treatment conditions, and evaluation results of the compositions for Examples 34-36 and Comparative Example 10. The work of breaking (%) is the value when the work of breaking of untreated hair (Comparative Example 10) is set to 100%.

[0069] [Table 9]

[0070] As shown in Table 9, a comparison of Example 35 and Example 36 confirmed that the effect could be obtained even when the amount of Falcorex Gardenia B (genipin-containing plant extract) was reduced from 10% to 1%.

[0071] (8) Series 8 (Examination of component B) Table 10 summarizes the formulations, pH, treatment conditions, and evaluation results of the compositions for Examples 37-41 and Comparative Examples 11-12. Examples 37-41 are examples in which ethanol and other components were used as component (B). The work of breaking (%) is the value when the work of breaking of untreated hair (Comparative Example 11) is set to 100%.

[0072] [Table 10]

[0073] As shown in Table 10, when ethanol was used in addition to 1,3-BG, glycerin, 1-propanol, propylene glycol, and sorbitol, an improvement in hair strength was obtained in all cases. On the other hand, when PEG-200 was added in addition to ethanol, no improvement in hair strength was obtained.

[0074] (9) Series 9 (Effect of improving cuticle elasticity) Table 11 summarizes the formulations, pH, treatment conditions, and evaluation results of the compositions for Examples 42-44 and Comparative Example 13. The elastic modulus (%) of the cuticle surface is the value when the elastic modulus of the cuticle surface of untreated hair (Comparative Example 13) is set to 100%.

[0075] [Table 11]

[0076] As shown in Table 11, in all cases where gardenia concentrate, gardenia extract, and Falcorex gardenia B, which are iridoid compound-containing plant extracts, were used as component A, it was confirmed that the elastic modulus of the cuticle surface improved.

[0077] (10) Series 10 (Examination of component A) Table 12 summarizes the formulations, pH, treatment conditions, and evaluation results of the compositions for Example 45 and Comparative Example 14. The work of breaking (%) is the value when the work of breaking of untreated hair (Comparative Example 14) is set to 100%.

[0078] [Table 12]

[0079] As shown in Table 12, it was confirmed that an improvement in hair strength was also obtained when swertiamarin, a secoiridoid compound, was used as component A.

[0080] The embodiments disclosed herein should be understood to be illustrative in all respects and not restrictive in any way. The scope of the present invention is defined by the claims and is intended to include all modifications in the sense and scope equivalent to the claims.

Claims

1. A hair composition comprising the following ingredients (A) and (B). (A) At least one iridoid compound selected from iridoids and secoiridoids. (B) Monovalent or polyvalent alcohols with 6 or fewer carbon atoms.

2. The amount of component (A) is less than or equal to the amount of component (B). The hair composition according to claim 1.

3. The amount of component (B) is 0.05% by mass or more. The hair composition according to claim 1.

4. The aforementioned component (B) contains at least 1,3-butylene glycol. A hair composition according to any one of claims 1 to 3.

5. A hair treatment method characterized by using the hair composition described in any one of claims 1 to 3.

6. (I) The step of applying the hair composition according to any one of claims 1 to 3 to hair, (II) The step of leaving the hair to which the hair composition has been applied at a temperature of 20°C or higher and 80°C or lower for 20 minutes or less, The hair treatment method according to claim 5.

7. Step (II) is a step of leaving the product at a temperature without heating for 20 minutes or less. The hair treatment method according to claim 6.

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