JP4509760B2 - Hair cosmetics - Google Patents

Description

  The present invention relates to a hair cosmetic and a hair treatment method for imparting firmness and firmness to hair.

  Conventionally, a method of replenishing degradation products and derivatives of collagen, keratin, etc. similar to hair components has been proposed as a method for improving the physical properties, appearance, and feel of hair by infiltrating substances into the hair, but it has not yet been proposed. It is not a sufficient effect.

  On the other hand, a technique for strengthening hair using alkyltrialkoxysilane on alkali-treated hair is known (see, for example, Patent Document 1). Further, by applying an organosilicon compound obtained by partial or total hydrolysis using an organosilicon compound or the like and partial or total polymerization to a keratin material such as a nail or hair, a keratin material A method for protecting and strengthening is also proposed (see, for example, Patent Documents 2 and 3).

However, in these techniques, since the organosilicon compound exists only on the keratin surface, there is a problem that the effect is lost by washing, or the feel of the keratin surface is not the original feel.
JP 61-7 Special Table 2000-510167 JP 2002-97114 A

  The present invention provides excellent firmness and firmness in a simple, reliable and short period of time for hair fibers, especially hair that does not have firmness and stiffness (hair damaged by chemical treatment, etc., thin hair of Westerners and elderly people, etc.). It aims at providing the hair cosmetics and the hair processing method which can be provided. Here, giving firmness and elasticity means improving hair elasticity.

  When the present inventors hydrolyze alkoxysilane, by allowing an organic acid to coexist, the silanol compound produced by hydrolysis is allowed to penetrate into the hair while suppressing the polymerization at an appropriate rate, and polymerized inside the hair. It is possible to impart excellent elasticity, and further, by coexisting a surfactant in the above-mentioned system, it is possible to promote the hydrolysis of alkoxysilane and simplify the stirring operation during the hydrolysis. It has been found that since the appearance of the system changes from white turbidity to transparency, the progress of hydrolysis is easy to understand, so that the reliability of the treatment is improved.

  The present invention provides the following general formula (1)

R ¹ _p Si (OR ² ) _4-p (1)

[Wherein, R ¹ and R ² represent a linear or branched alkyl group having 1 to 6 carbon atoms or a linear or branched alkenyl group having 2 to 6 carbon atoms, and p R ¹ and ( 4-p) R ² may be the same or different. p shows the integer of 0-3. ]
A hair cosmetic composition having a pH of 2 to 5 and comprising an alkoxysilane represented by formula (II), an organic acid, water, and a surfactant is provided.

  Further, the present invention stirs and mixes the above-mentioned hair cosmetics, and after applying that it is confirmed to the system to be transparent and applied to the hair, is produced by hydrolysis of the alkoxysilane represented by the general formula (1) General formula (2)

R ¹ _p Si (OH) _n (OR ² ) _4-pn (2)

[Wherein R ¹ , R ² and p represent the same meaning as described above, and n represents an integer of 1 or more and (4-p) or less. p R ¹ and (4-p−n) R ² may be the same or different. ]
A hair treatment method for allowing the silanol compound represented by the formula to penetrate into the hair is provided.

  According to the present invention, since the silanol compound produced by hydrolysis of alkoxysilane can be penetrated into the hair and polymerized inside the hair, the hair diameter is increased. As a result, excellent firmness and firmness can be imparted to hair, particularly hair that does not have firmness and firmness (damaged hair, fine hair, etc.). Furthermore, the effect of improving the cohesiveness of the hair and the effect of correcting the comb hair are also obtained. In addition, the effect persists even after repeated shampooing. Further, the processing operation can be performed simply, reliably and in a short time.

  “Hair treatment” in the hair treatment method of the present invention refers to modifying the hair into a firm, firm, and coherent hair quality.

[Alkoxysilane (1)]
In R ¹ and R ² in the general formula (1), examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, an isobutyl group, and a t-butyl group. , Vinyl group, allyl group and the like. In particular, R ² is preferably an ethyl group from the viewpoint of safety of by-products generated by hydrolysis, reactivity of hydrolysis reaction, and the like.

  When the hair cosmetic composition of the present invention is a two-component type, the alkoxysilane (1) is blended with the first agent not containing water, mixed with the second agent containing water, and then water-soluble by hydrolysis. It becomes a silanol compound (2) and can penetrate into the hair. From the viewpoint of physical properties of the silanol compound (2) to be produced and penetrability into hair, p in the general formula (1) is preferably 0-2. Examples of the alkoxysilane (1) include alkyl (C1-6) trimethoxysilane, alkyl (C1-6) triethoxysilane, dialkyl (C1-6) diethoxysilane, and the like.

  The content of alkoxysilane (1) is in the hair cosmetic composition of the present invention from the point of reactivity due to the crosslinking reaction (in the case of two-component type, in the total composition of the first agent and the second agent; the same applies hereinafter) 4% by weight or more, particularly 12% by weight or more, and preferably 82% by weight or less, particularly preferably 58% by weight or less. Further, the content of the alkoxysilane (1) in the first agent is preferably 70 to 100% by weight, more preferably 80 to 100% by weight, and particularly preferably 90 to 100% by weight from the viewpoint of storage stability.

[Organic acid]
Organic acids include oxalic acid (pKa = 1.04, 3.82), maleic acid (pKa = 1.75, 5.83), aspartic acid (pKa = 1.93, 3.70), salicylic acid (pKa = 2.81), tartaric acid (pKa = 2.82, 3.96) , Fumaric acid (pKa = 2.85, 4.10), citric acid (pKa = 2.90, 4.34), malic acid (pKa = 3.24, 4.71), succinic acid (pKa = 4.00, 5.24), formic acid (pKa = 3.55), lactic acid ( Examples include pKa = 3.66), glutaric acid (pKa = 4.13, 5.01), adipic acid (pKa = 4.26, 5.03), acetic acid (pKa = 4.56), propionic acid (pKa = 4.67), etc. From the standpoint of ease, an organic acid having a first dissociation index (pKa1) in the range of 1.9 to 5.0, particularly 3.5 to 5.0 is preferable. Of these, glutaric acid, adipic acid, acetic acid, and propionic acid are preferable because the polymerization reaction of the silanol compound (2) can be easily controlled, and adipic acid with a low odor is particularly preferable.

  In the case where the hair cosmetic composition of the present invention is a two-component type, the organic acid can be dissolved in the second agent separately from the alkoxysilane (1) compounded in the first agent. It is preferable from the point. The content of the organic acid is preferably 0.001 to 5% by weight, particularly preferably 0.001 to 1% by weight in the hair cosmetic composition of the present invention, from the viewpoint of suppressing the polymerization reaction.

〔water〕
When the hair cosmetic composition of the present invention is a two-component type, water is blended in the second agent separately from the alkoxysilane (1) blended in the first agent, and its content is sufficient for the hair. From the viewpoint of allowing the silanol compound (2) produced by hydrolysis to sufficiently penetrate into the hair, it is preferably 20 to 95% by weight, particularly 30 to 86% by weight in the hair cosmetic composition of the present invention.

[Surfactant]
When the hair cosmetic composition of the present invention is a two-component type, the surfactant is contained in at least one of the first agent and the second agent, but is preferably contained in the second agent. However, when the first agent does not contain moisture, it can be contained in the first agent. As the surfactant, any of a nonionic surfactant, an anionic surfactant, a cationic surfactant, and an amphoteric surfactant can be used.

  Nonionic surfactants include polyoxyalkylene alkyl ether, polyoxyalkylene alkenyl ether, higher fatty acid sucrose ester, polyglycerin fatty acid ester, higher fatty acid mono- or diethanolamide, polyoxyethylene hydrogenated castor oil, polyoxyethylene sorbitan fatty acid Examples thereof include esters, polyoxyethylene sorbite fatty acid esters, alkyl saccharide surfactants, alkyl amine oxides, and alkyl amido amine oxides. Of these, polyoxyalkylene alkyl ether and polyoxyethylene hydrogenated castor oil are preferable, and polyoxyethylene alkyl ether is particularly preferable.

  Anionic surfactants include alkyl benzene sulfonates, alkyl or alkenyl ether sulfates, alkyl or alkenyl sulfates, olefin sulfonates, alkane sulfonates, saturated or unsaturated fatty acid salts, alkyl or alkenyl ether carboxylates, Examples include α-sulfone fatty acid salts, N-acyl amino acid type surfactants, phosphate mono- or diester type surfactants, and sulfosuccinate esters. Counter ions of the anionic residue of the surfactant include alkali metal ions such as sodium ion and potassium ion; alkaline earth metal ions such as calcium ion and magnesium ion; ammonium ion; alkanol group having 2 or 3 carbon atoms Alkanolamine having 1 to 3 (for example, monoethanolamine, diethanolamine, triethanolamine, triisopropanolamine, etc.). Examples of the counter ion of the cationic residue include halide ions such as chloride ion, bromide ion and iodide ion, methosulphate ion and saccharinate ion.

  Examples of the cationic surfactant include quaternary ammonium salts represented by the following general formula (3).

[In the formula, R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 28 carbon atoms or a benzyl group, and simultaneously become a hydrogen atom or a benzyl group; Except when it becomes an alkyl group. An ⁻ represents an anion. ]

Here, one of R ³ and R ⁴ is preferably an alkyl group having 16 to 24 carbon atoms, more preferably 22 alkyl groups, particularly a linear alkyl group, and the other is a lower alkyl group having 1 to 3 carbon atoms, particularly A methyl group is preferred. Examples of the anion An ^- include halide ions such as chloride ions and bromide ions; organic anions such as ethyl sulfate ions and methyl carbonate ions. Halide ions, particularly chloride ions are preferred.

  As the cationic surfactant, mono long-chain alkyl quaternary ammonium salts are preferable, and specific examples include cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, aralkyltrimethylammonium chloride, and behenyltrimethylammonium chloride. Stearyl trimethyl ammonium and behenyl trimethyl ammonium chloride are preferable.

  Examples of amphoteric surfactants include imidazoline series, carbobetaine series, amide betaine series, sulfobetaine series, hydroxysulfobetaine series, and amide sulfobetaine series.

  Among these, from the viewpoint of emulsifying ability (miscibility of alkoxysilane (1), organic acid, water and surfactant), nonionic surfactants of HLB 9-15, particularly 11-14 are preferred. Here, HLB indicates a calculated value by the Griffin method.

  Two or more kinds of surfactants can be used in combination. From the viewpoint of emulsification and hydrolysis at the time of mixing, the content is 0.1 to 20% by weight in the hair cosmetic composition of the present invention, Is preferably 0.5 to 15% by weight, particularly 1 to 10% by weight.

[PH]
The hair cosmetic composition of the present invention is required to hydrolyze the alkoxysilane (1) to produce the silanol compound (2), and to allow the silanol compound (2) to penetrate into the hair and cause a polymerization reaction in the hair. In addition, it is necessary to delay the polymerization reaction. For this reason, pH (20 degreeC) is adjusted to 2-5, but 3-4 are preferable. In the case of the two-agent type, the pH (20 ° C.) of the second agent is adjusted to the above range.

[Other ingredients]
In addition, for the purpose of dissolving the silanol compound (2), a water-soluble organic solvent such as methanol or ethanol having 1 to 3 carbon atoms such as lower primary alcohol or glycerin can be used. When the hair cosmetic composition of the present invention is applied to hair, the hair does not swell sufficiently, and the silanol compound (2) does not sufficiently penetrate. Therefore, the amount of the water-soluble organic solvent used is preferably 35% by weight or less, particularly 20% by weight or less in the hair cosmetic composition of the present invention. In addition to this, the hair cosmetic material after hydrolysis of the alkoxysilane (1) contains R ² OH as a by-product.

  In addition, the hair cosmetic of the present invention includes pH adjusters, oils, silicone derivatives, cationic polymers, humectants, viscosity modifiers, fragrances, pigments, UV absorbers, antioxidants, antibacterial agents, preservatives, etc. Depending on the purpose, it can be blended appropriately.

[Form of hair cosmetic]
The form of the hair cosmetic composition of the present invention includes a first agent containing alkoxysilane (1) and a second agent containing an organic acid and water and having a pH of 2 to 5 in order to ensure long-term stability. A two-component system comprising a surfactant in at least one of the first agent and the second agent is preferred, but alkoxysilane (1), organic acid, water and surfactant, and other optional components are used immediately before use. It may be prepared by mixing the components and adjusting the pH to 2-5.

  When the hair cosmetic composition of the present invention is of a two-component type, the surfactant is preferably contained in the second agent, but can also be contained in the first agent when the first agent does not contain moisture. Moreover, although it is preferable to contain other arbitrary components in the 2nd agent, if it is a non-aqueous liquid component and a solid component, it can also mix | blend in a 1st agent.

  When the hair cosmetic composition of the present invention is prepared by mixing the alkoxysilane (1), organic acid, water and surfactant, and other optional components immediately before use, the mixing order is not particularly limited. Since the silanol compound (2) produced by the decomposition immediately starts a polymerization reaction, in order to suppress this, it is preferable to mix the alkoxysilane (1) after mixing the organic acid, water and the surfactant.

  Mixing the first and second agents of the two-component hair cosmetic of the present invention immediately before use, or mixing alkoxysilane (1), organic acid, water and surfactant, and other optional components Thus, the alkoxysilane (1) becomes a water-soluble silanol compound (2) by hydrolysis, and can penetrate into the hair. From the viewpoint of the physical properties of the silanol compound (2) and the penetrability into hair, p in the general formula (2) is preferably 0 to 2, n is preferably 2 to 4, and (4-pn) is 0. Is preferred. Further, the molecular weight of the silanol compound (2) is preferably 300 or less, particularly preferably 90 to 200, from the viewpoint of easy penetration into hair.

[Hair treatment method]
In order to treat the hair using the hair cosmetic composition of the present invention, the first and second agents of the two-component hair cosmetic composition of the present invention are mixed immediately before use, or after alkoxysilane (1), organic acid, After mixing water, surfactant, and other optional components immediately before use, the mixture is stirred and mixed by means such as shaking, and it is visually confirmed that the mixed solution has become transparent. It is preferable to apply. The mixing ratio of the first agent and the second agent (weight ratio of the first agent / second agent) is preferably 80/20 to 1/99, more preferably 60/40 to 20/80. Immediately after mixing, it was in a white turbid emulsified state or partially emulsified state, but it remained transparent as it was or continued stirring as necessary, so that the alkoxysilane (1) was hydrolyzed, silanol compound ( It can be confirmed that 2) was generated.

  If the resulting mixture is allowed to stand, the polymerization reaction of the silanol compound (2) proceeds, so it is preferable to apply the obtained mixture to the hair within 30 minutes, particularly within 15 minutes. This allows the silanol compound (2) to penetrate into the hair. The hair to be applied may be wet or dry. It is preferable to apply 0.5 to 3 g of the mixture to 1 g of dried hair. The target to be applied may be human hair or hair such as a wig.

  In order to allow the silanol compound (2) to sufficiently permeate into the hair, the time applied to the hair is preferably 15 to 90 minutes, particularly preferably 20 to 60 minutes. The silanol compound (2) penetrates into the hair by allowing it to stand for a certain time after application. Under the present circumstances, you may heat the application part of hair to 40-90 degreeC, Preferably it is 40-60 degreeC. After thoroughly infiltrating the silanol compound (2) into the hair, remove excess hair cosmetics with a towel if necessary, and then dry the hair with warm air for the purpose of accelerating the polymerization reaction of silanol inside the hair. The acid or base may be applied to the hair. Since the silanol compound adhering to the hair surface after the polymerization reaction and the polymer thereof become a film after drying the hair and cause a deterioration of the hair feel, it is preferable that the silanol compound is sufficiently removed at the end with a shampoo or the like.

Test example 1
To a 300 mL eggplant-shaped flask, weigh 74.9 g of ion-exchanged water, add 0.1 g of various additives (organic acid, inorganic acid, or alkali agent) shown in Table 1, and dissolve by stirring at room temperature. 25.0 g of ethoxysilane was mixed. This mixture was stirred at a stirring speed of 200 rpm using a stirring rod equipped with a stirring blade made of 7-cm half-moon Teflon (registered trademark) in a constant temperature water bath at 40 ° C. When initially allowed to stand, the two phases are separated, but the methylsilanetriol produced by the hydrolysis reaction is water-soluble, so that it becomes a transparent homogeneous aqueous solution (including methylsilanetriol, ethanol, and water) after the reaction is completed. When no additive was added and when an alkali agent was used, it took 5 hours or more to complete the hydrolysis.
When stirring is continued, methylsilanetriol is polymerized to increase the molecular weight and become insoluble in the water-ethanol solution, so that the solution becomes cloudy. If the time until the transparent solution becomes cloudy is short, methylsilanetriol does not sufficiently permeate into the hair and polymerizes in the vicinity of the hair surface, so that it is not possible to obtain an excellent effect of imparting firmness and stiffness to the hair. The time until the transparent solution after the hydrolysis became cloudy was measured and shown in Table 1.

  As is apparent from Table 1, when an inorganic acid or alkali agent is used as an additive, the silanol compound is rapidly polymerized after hydrolysis and cannot be penetrated into the hair.

Example 1
A hair cosmetic (pH 3.5 to 3.8; 20 ° C.) comprising 25.0% by weight of methyltriethoxysilane, 0.8% by weight of adipic acid, 10% by weight of the surfactant shown in Table 2 and the balance of ion-exchanged water was prepared. Immediately, 30 mL of these hair cosmetics are put into a 50 mL sealed container, stirred (shake the container 30 times by hand), and then left to stand. Observation was made every 5 minutes, and when separation occurred, stirring was performed again. The pH (25 ° C.) was measured with a pH meter manufactured by HORIBA.
As a control, two hair cosmetics containing 25.0% by weight of methyltriethoxysilane, 0.8% by weight of adipic acid and the balance of ion-exchanged water and containing no surfactant were also prepared. The other was continuously stirred with a magnetic stirrer.

(Evaluation of miscibility)
Table 2 shows the state of the mixed solution 5 minutes after the first stirring. “Emulsification” in the table indicates a state in which the entire solution is uniformly clouded visually, and “partially emulsified” indicates that the upper layer or a part of the lower layer of the solution is clouded and the remaining is transparent. “Two-phase separation” indicates a state in which a transparent liquid is separated with a boundary line vertically.

[Evaluation of hydrolysis speed]
The time until the mixed solution becomes uniform and transparent after the first shaking and stirring is shown in the table.

Example 2
The first agent composed of alkoxysilane and the second agent containing acid, water, surfactant and pH adjuster (sodium hydroxide) are mixed to prepare the hair cosmetic shown in Table 3, and the evaluation shown below Went. The results are also shown in Table 3.
Each hair cosmetic was mixed and stirred with the first agent and the second agent, and applied to the hair after the appearance became transparent.

(1) Evaluation of sorption amount of silicon compound on hair, bending elasticity test <hair treatment method>
A hair bundle of 5 g was prepared using hair without a chemical treatment history collected from one Westerner. Next, 10 g of the hair cosmetic shown in Table 3 was uniformly applied to the hair bundle, and then wrapped in a wrap and allowed to stand in an oven at 48 ° C. for 1 hour. Thereafter, excess hair cosmetic was wiped off with a towel and completely dried using a hot air dryer for 15 minutes to polymerize the silanol compound in the hair. Then, it processed with the shampoo and hair rinse of the composition shown below, and dried.

·shampoo
(weight%)
Polyoxyethylene (2.5) sodium lauryl ether sulfate (25% by weight aqueous solution) 62.00
Lauric acid diethanolamide 2.28
Edetate disodium 0.10
Sodium benzoate 0.50
Oxybenzone 0.03
Phosphoric acid (75 wt% aqueous solution) 0.10
Dibutylhydroxytoluene 0.01
Sodium chloride 0.80
Red No. 106 0.00012
Fragrance 0.26
Purified water balance

・ Hair rinse
(weight%)
Stearyltrimethylammonium chloride (28 wt% aqueous solution) 3.0
Cetanol 3.0
Propylene glycol 3.0
Methylparaben 0.1
Purified water balance

<Evaluation method of sorption amount of silicon compound on hair>
An ICP (inductively coupled plasma) emission spectrometer (Horiba, JY238ULTRACE) was used to evaluate the amount of silicon compound sorbed on the hair. The sorption amount of the silicon compound was determined as the sorption amount of silicon element based on the amount of silicon element measured using ashing / alkaline melting / ICP method.
0.1 g of sample is collected in a platinum crucible, carbonized until no smoke is produced with a heater, and then placed in an electric furnace at 550 ° C. for 2 hours for ashing. After cooling, add 1 g of alkaline flux (Na ₂ CO ₃ : H ₃ BO ₃ = 5: 2) on the remaining ash, melt in alkali at 950 ° C. for 30 minutes, cool and dissolve in 4 mL of 6N hydrochloric acid. The sample solution was made up to 50 mL with pure water. Measurement was performed three times at an absorption wavelength of 251.512 nm and an integration time of 3 seconds, and the amount of silicon element was determined from the average value using a calibration curve. The calculation method of the silicon element sorption amount to the hair is as follows.

  Silicon element sorption amount (%) = [silicon element amount (mg) / hair weight (g)] × 0.1

<Bending elasticity test method>
For the bending elasticity test, a “pure bending test machine (Kato Tech, KES-FB2-S)” was used, and the force required for bending the hair (bending elasticity) was measured.
The hair was cut off by 3 cm at both ends, and only hair having a length of 5 cm or more was used for the evaluation test. They were also placed in 65% relative humidity for at least 24 hours prior to measurement. As shown in FIG. 1, a measurement sample was prepared by attaching 50 human hairs to two sheets of graph paper having a length of 51 mm and a width of 15 mm arranged at intervals of 10 mm. This was attached to a pure bending tester and the bending elasticity was measured. The measurement conditions were 20 ° C., relative humidity 65%, sensitivity: 2 × 1, and maximum bending curvature: 2.5 cm ⁻¹ . The bending elasticity was determined from the slope of a straight line obtained by linearly approximating the force required for bending per hair having a curvature of 1.0 to 2.0 cm ⁻¹ .

(2) Sensory evaluation
Ten professional panelists evaluated the “feeling of improving hair stiffness and stiffness” and “feeling of unity hair” according to the following criteria, and indicated the total value.

<Improve feeling of hair elasticity>
(Comparing untreated hair with treated hair, treated hair is better)
3: Clearly feels firm and firm 2: Feels firm and firm 1: Feels somewhat firm and firm 0: Cannot say either -1: Feels firm or firm

<A feeling of unity hair>
(Comparing untreated hair with treated hair, treated hair is better)
3: I feel that there is clearly a unity 2: I feel that there is a unity 1: Somewhat I feel that there is a unity 0: I can not say either -1: I feel that there is no unity

It is a figure which shows the measurement sample used for the bending elasticity test.

Claims (5)

The following general formula (1)
R ¹ _p Si (OR ² ) _4-p (1)
[Wherein, R ¹ and R ² represent a linear or branched alkyl group having 1 to 6 carbon atoms or a linear or branched alkenyl group having 2 to 6 carbon atoms, and p R ¹ and ( 4-p) R ² may be the same or different. p is an integer of 0-2. ]
Alkoxysilane represented in, organic acids, water and surfactant just prior to use by stirring a mixture prepared hair cosmetic composition of PH2～5, the mixed solution within 30 minutes after confirming that became clear The following general formula (2) generated by hydrolysis of alkoxysilane represented by the general formula (1) by applying to hair and leaving it for 15 to 90 minutes
R ¹ _p Si (OH) _n (OR ² ) _4-pn (2)
[Wherein R ¹ , R ² and p represent the same meaning as described above, and n represents an integer of 1 or more and (4-p) or less. p R ¹ and (4-p−n) R ² may be the same or different. ]
In the represented molecular weight of 300 or less silanol compound to penetrate the hair, the hair treatment method Ru is polymerized inside the hair. The following general formula (1)
R ¹ _p Si (OR ² ) _4-p (1)
[Wherein, R ¹ and R ² represent a linear or branched alkyl group having 1 to 6 carbon atoms or a linear or branched alkenyl group having 2 to 6 carbon atoms, and p R ¹ and ( 4-p) R ² may be the same or different. p is an integer of 0-2. ]
And a second agent containing an organic acid and water and having a pH of 2 to 5, and at least one of the first agent and the second agent is a surfactant. those containing hair cosmetic first agent and the stirring mixed immediately before use and a second agent, the mixed solution is applied to the hair within 30 minutes after confirming that it became transparent, 15 The following general formula (2) generated by hydrolysis of the alkoxysilane represented by the general formula (1) by leaving it for 90 minutes
R ¹ _p Si (OH) _n (OR ² ) _4-pn (2)
[Wherein R ¹ , R ² and p represent the same meaning as described above, and n represents an integer of 1 or more and (4-p) or less. p R ¹ and (4-p−n) R ² may be the same or different. ]
In the represented molecular weight of 300 or less silanol compound to penetrate the hair, the hair treatment method Ru is polymerized inside the hair. The hair treatment method according to claim 1 or 2 , wherein the organic acid is an organic acid having a first dissociation index (pKa1) in the range of 1.9 to 5.0. The hair treatment method according to any one of claims 1 to 3 , wherein the surfactant is a nonionic surfactant of HLB 9-15. The hair treatment method according to any one of claims 1 to 4 , wherein the application part is heated after the hair cosmetic is applied to the hair.