JP5777083B2 - Hair deformation treatment method - Google Patents

Description

  The present invention relates to a hair deformation treatment method for imparting straightness to hair using a one-component hair treatment agent having hair deformability.

  There are various methods for imparting straightness to hair, but a typical one is a treatment method using a hair straightener. In this straightening treatment, generally, a disulfide bond in curly hair is opened with a reducing agent to generate a mercapto group, which is straightened with a device such as a comb, and an oxidant is used in this state. This is a process for straightening curly hair by re-forming a new disulfide bond at a position different from the original.

  For these reasons, it is normal to use a two-component hair treatment agent composed of a first agent blended with a reducing agent and a second agent blended with an oxidizing agent in straightening treatment (patent) References 1, 2, etc.).

JP 2000-256146 A JP 2002-356408 A

  By the way, in the hair straightening treatment using the two-component hair treatment agent, as described above, the step of applying the first agent containing the reducing agent to the curly hair, the step of extending the curly hair, The process of applying the second agent containing the oxidizing agent is essential, and furthermore, there is usually a process of washing hair (curly hair) and a process of drying between each process, so from the start to the end of the process. Is usually very long, 3-5 hours. For these reasons, there is a need for a method that can complete the treatment for imparting straightness to curly hair in a shorter time.

  Therefore, a curly hair straightening treatment method in which the number of steps is reduced by using a one-component hair treatment agent has been studied. It is difficult to combine the reducing agent for breaking the disulfide bond of hair and the oxidizing agent for oxidizing the mercapto group generated by the reduction into one treatment agent to effectively bring out the functions of both. For this reason, for example, it is conceivable that a reducing agent is blended in a one-component hair treatment agent, and a disulfide bond is reformed from the mercapto group in the curly hair generated thereby by oxidation with air or the like.

  However, it is difficult to oxidize the mercapto group produced by the reducing agent without using an oxidizing agent to sufficiently re-form the disulfide bond. There is a problem of sticking.

  For these reasons, there is a need for the development of a treatment method that can impart straightness to the hair and can suppress the stickiness of the hair after the treatment without taking as much labor and time as the curly hair straightening treatment.

  This invention is made | formed in view of the said situation, The objective provides the hair deformation processing method which can provide favorable straightness to hair, suppressing the sticking of the hair tip in the hair after a process. There is.

  The hair deformation treatment method of the present invention that has achieved the above object comprises a step of applying to a hair a one-component hair treatment agent having a pH of 6 to 10 and containing at least one sulfite or bisulfite (I And a step (II) of adding heat to the hair after the step (I) to impart straightness to the hair.

  Generally, thioglycolic acid or a salt thereof, cysteine or a salt thereof, or the like is used as a reducing agent in a hair treatment agent used for straightening hair. These reducing agents are as described above. The function of cleaving disulfide bonds in hair by reduction is excellent. For this reason, curly hair treated with a hair treatment agent containing such a reducing agent has a number of disulfide bonds cleaved to form mercapto groups, so these mercapto groups are oxidized by an oxidizing agent. Thus, if the disulfide bond is not re-formed, the hair ends will be particularly stuck.

  Although sulfites and bisulfites are also known as reducing agents for hair treatment agents, the present inventors, according to hair treatment agents containing sulfites or bisulfites, unexpectedly reduced other reductions. It was found that, unlike a hair treatment agent containing an agent, cleavage by reduction of disulfide bonds hardly occurs.

  On the other hand, a hair treatment agent containing sulfite or bisulfite has poor curly straightening ability. However, if the curly hair applied with this hair treatment agent is treated at a temperature exceeding 220 ° C., the shrinkage is reduced. It was found that it can be corrected to a good straight shape by stretching. In the case of curly hair coated with a hair treatment agent containing a reducing agent such as thioglycolic acid or its salt or cysteine or its salt, the cleavage of disulfide bonds further proceeds when treated at a temperature exceeding 220 ° C. It was also found that in the case of curly hair coated with a hair treatment agent containing hydrogen sulfite, the cleavage of disulfide bonds does not proceed even when the treatment is performed at a temperature exceeding 220 ° C.

  In the hair deformation treatment method of the present invention, based on such knowledge, a one-component hair treatment agent containing sulfite or bisulfite and having a pH of 6 to 10 is used. Hair) was treated at a temperature exceeding 220 ° C. According to the hair deformation treatment method of the present invention, for example, as in the case of a treatment method using a conventional two-component hair straightener, it does not lead to imparting straightness to the hair semipermanently. Compared with the method, the number of steps to complete the treatment is less and the treatment time can be shortened, and the hair ends after the treatment, which can occur in the treatment method using a one-part hair straightener, are suppressed. Good straightness that lasts for a long time can be imparted to the hair.

  ADVANTAGE OF THE INVENTION According to this invention, the hair deformation | transformation processing method which can provide favorable straightness to hair can be provided, suppressing the sticking of the hair tip in the hair after a process.

  Step (I) according to the method of the present invention is a step of applying a one-component hair treatment agent to hair (curly hair).

  The one-component hair treatment agent used in the step (I) has hair deformability and is a mixture of at least one sulfite or bisulfite.

  Examples of sulfites that can be blended in a one-component hair treatment agent include sodium sulfite, potassium sulfite, calcium sulfite, barium sulfite, and ammonium sulfite. Examples of the bisulfite that can be blended in the one-component hair treatment agent include sodium bisulfite, potassium bisulfite, and ammonium bisulfite. For single-agent hair treatment agents, only one of the above sulfites and bisulfites may be used, or multiple types of sulfites or multiple types of bisulfites may be used, Furthermore, you may use together 1 or more types of sulfite and 1 or more types of bisulfite. Among these, sodium sulfite or sodium hydrogen sulfite is preferable from the viewpoint of stability and safety.

  Blending amount of sulfite or bisulfite in single-agent hair treatment agent (if sulfite and bisulfite are blended in single-agent hair treatment agent, the total amount. One-component hair The same applies to the blending amount of sulfite or bisulfite in the treatment agent.) Is 0.5% by mass from the viewpoint of better securing the effect (the effect of straightening curly hair into a straight shape). Preferably, it is preferably 4% by mass or more. However, if the amount of sulfite or bisulfite in the one-component hair treatment agent is too large, the hair deformability may be lowered, and the effect of suppressing the sticking of the hair tip may be reduced. is there. Therefore, the blending amount of sulfite in the one-component hair treatment agent is preferably 10% by mass or less, and more preferably 8% by mass or less.

  In general, sulfite or bisulfite is known to have high reducing ability in the acidic region, but in the method of the present invention, the pH of the one-component hair treatment agent is adjusted to 6-10. In this way, the hair deformability is enhanced, and the hair ends after the treatment can be prevented from sticking.

  The pH of the one-component hair treatment agent can be adjusted, for example, by blending an alkali agent with the one-component hair treatment agent, if necessary. Examples of such an alkaline agent include sodium carbonate, ammonium hydrogen carbonate, aqueous ammonia, potassium hydroxide, sodium hydroxide, sodium borate, monoethanolamine, diethanolamine, and triethanolamine.

  The single-agent hair treatment agent uses water as the main medium. As used herein, “with water as the main medium” means that the amount of water is 50% by mass or more in the entire medium of the one-component hair treatment agent. As the medium, only water may be used, and if necessary, an organic solvent such as lower alcohol (alcohol having 6 or less carbon atoms) such as ethanol and isopropanol may be used in combination with water. Moreover, it is preferable that the compounding quantity of the medium in 1 agent type hair treatment agent is 40-95 mass%, for example.

  Moreover, it is preferable that dithiodiglycolate is blended in the one-component hair treatment agent, which can enhance the hair straightening effect and improve the elongation of the hair after treatment. In addition, the softness of the hair after treatment can be increased.

  Examples of the dithiodiglycolate include diammonium dithiodiglycolate, dimonoethanolamine dithiodiglycolate, ditriethanolamine dithiodiglycolate, and only one of these may be used. Two or more kinds may be used in combination.

  The blending amount of the dithiodiglycolate in the one-component hair treatment agent is preferably 0.5% by mass or more from the viewpoint of ensuring better the effect of its use. However, if the amount of dithiodiglycolate in the one-component hair treatment agent is too large, the unpleasant odor generated during the treatment tends to be strong. Therefore, it is preferable that the compounding quantity of the dithiodiglycolate in 1 agent type hair treatment agent is 10 mass% or less.

  Moreover, it is preferable to mix | blend a water-soluble polymer with 1 agent type hair treatment agent, and this can enlarge the viscosity of 1 agent type hair treatment agent, and can improve operativity, for example, to curly hair Can be more easily applied. In addition, by blending the water-soluble polymer, it is possible to more favorably suppress the stickiness of the hair ends after the treatment.

  Examples of the water-soluble polymer include natural polymers such as carrageenan, agar, xanthan gum, gelatin, pectin, tamarind seed polysaccharide, locust bean gum, guar gum, gum arabic, tragacanth gum, hyaluronic acid or a salt thereof, and chitosan; Ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, cationized cellulose, starch phosphate ester, sodium starch glycolate, amphoteric starch, cationized guar gum, carboxymethyl hydroxypropylated guar gum, hydroxypropylated guar gum Natural polymer derivatives such as polyvinylpyrrolidone, carboxyvinyl polymer, acrylic acid / meta Synthetic polymers such as acrylic acid alkyl copolymer; and the like, may be used only one of these may be used in combination of two or more.

  The blending amount of the water-soluble polymer in the one-component hair treatment agent is preferably 1% by mass or more from the viewpoint of better ensuring the effect of its use. However, if the water-soluble high molecular weight in the one-component hair treatment agent is too large, the viscosity of the one-component hair treatment agent becomes too high, and the operability may be lowered. Therefore, it is preferable that the compounding quantity of the water-soluble polymer in 1 agent type hair treatment agent is 10 mass% or less.

  In addition to the above-described components, the one-component hair treatment agent can be blended with various components used in normal hair cosmetics as long as the effects of the present invention are not impaired.

  There is no restriction | limiting in particular about the dosage form of 1 agent type hair treatment agent, It is good also as any dosage forms, such as lotion shape, emulsion, cream shape, and gel shape.

  In the step (I), it is preferable that the curly hair to which the one-component hair treatment agent is applied is left, for example, for about 3 to 30 minutes, and then the step (II) is performed. Thereby, the 1 agent type hair treatment agent can penetrate | invade favorably in curly hair, and the effect which provides straightness to hair can be heightened more.

  Step (II) according to the method of the present invention is a step of applying heat to the curly hair after applying the one-component hair treatment agent, and this step makes the curly hair a good straight shape.

  In step (II), heat exceeding 220 ° C. is applied to the curly hair. If the temperature at this time is too low, a good straight shape cannot be imparted to curly hair. The temperature of the heat applied to the curly hair in the step (II) is preferably 225 ° C. or higher, and more preferably 230 ° C. or higher because the effect of imparting straightness can be further enhanced. However, if the temperature of heat applied to the curly hair is too high, the curly hair may be damaged. Therefore, the temperature is preferably 250 ° C. or lower.

  In step (II), heat is applied in a state where the curly hair is stretched into a straight shape. Specifically, for example, the hair is stretched into a straight shape on a plate portion of a straight hair iron having a temperature exceeding 220 ° C. It is preferable to apply heat to the curly hair by a method in which the curly hair is sandwiched between the roots and the ends of the hair instead of being simply pressed as in the prior art.

  As a hair curling iron, the temperature of the plate part (however, the surface temperature) can be heated to more than 220 ° C., and any hair can be straightened under heating, and is not limited to a specific one. Various things can be used.

  The step (II) may be carried out immediately after the curly hair coated with the one-component hair treatment agent in the step (I) is allowed to stand for the above-mentioned time, but after the standing, the curly hair is washed with water. A step may be provided, and then step (II) may be performed. Thereby, the effect which provides straightness to hair can be heightened more.

  Moreover, the process of drying a curly hair may be provided after the said water washing process after process (I), and process (II) may be implemented after that. In this drying step, it is preferable that a part of the moisture remains in the curly hair, thereby further enhancing the effect of imparting straightness to the hair.

  After step (II), if necessary, a step of washing and drying hair may be provided. Prior to step (I), a step of washing curly hair and a step of drying curly hair after washing may be provided.

  In the method of the present invention, unlike the conventional hair straightening treatment method using a two-component hair treatment agent, a step of applying a second agent containing an oxidizing agent to the hair and fixing the straight shape, and Since the washing process for washing away the second agent and the subsequent drying process can be omitted, for example, the treatment can be completed within 1 hour (or within 30 minutes), and the conventional hair straightening treatment Compared with the method, the processing time can be significantly shortened.

  Hereinafter, the present invention will be described in detail based on examples. However, the following examples do not limit the present invention. In the following examples, “%” means “mass%”. Moreover, as a compounding quantity of 1 agent type hair treatment agent, the compounding quantity of each component is shown by% so that it may become 100% on the whole, and the display of the% is abbreviate | omitted in Table 1-Table 3 of a postscript, and mix | blending Display only numerical values representing quantities.

Experiment 1: Effect confirmation test by hair deformation treatment method <Preparation of one-component hair treatment agent>
One-component hair treatment agents of Preparation Examples 1 to 18 were prepared with the compositions shown in Tables 1 to 3.

  In Tables 1 to 3, the column “Water” is “100”, and the total amount of each component other than water constituting the one-component hair treatment agent is 100% by adding the amount of water. It means that I did it. Further, “5.5EO” in “polyoxyethylene cetyl ether (5.5EO)” described in Tables 1 to 3 means that the average number of moles of ethylene oxide added is 5.5. doing. Furthermore, “appropriate amount” in the columns of “monoethanolamine solution” and “phosphoric acid aqueous solution” in Tables 1 to 3 was used in such an amount that the pH of each one-component hair treatment agent was a value shown in each table. It means that.

<Evaluation of hair after treatment>
The hair deformation treatment was performed using the one-component hair treatment agents of Preparation Examples 1 to 18, and evaluation was performed on the elongation of the hair after the treatment, the stickiness of the hair ends, and the softness.

  First, a large number of curly hairs having a length of 25 cm (length measured in a natural state without being stretched) were collected from the same person, and 1.5 g each was collected to prepare a plurality of hair bundles. These hair bundles were washed with a 10% sodium laureth aqueous solution, washed with water, and then dried to obtain test hair bundles.

  After applying 2 g of 1-component hair treatment agent to each test hair bundle, it was left to stand for 15 minutes while being heated to 50 ° C., then washed with water and dried to leave some moisture. Then, these test hair bundles were sandwiched between plate portions of a straight hair iron heated to a predetermined temperature, and passed through from the root toward the hair tip side to complete the treatment. In addition, the heating temperature by the straight hair iron was 180 degreeC, 200 degreeC, and 230 degreeC.

  And 5 expert panelists according to the following standard about the elongation of the hair concerning each test hair bundle after the treatment (being able to give a good straight shape), the tip of the hair, and the softness Evaluated and scored.

(Evaluation criteria for hair elongation)
Not stretched ... 0 points,
Slightly growing ... 1 point,
Elongating ... 2 points.

(Evaluation criteria for sticking of hair ends)
Sticking ... 0 points,
Slightly stuck ... 1 point,
It is not dusty in appearance, but it can be seen that it is dusty when touched.
Not sticking ... 3 points.

(Evaluation criteria for softness of hair)
Hard compared to untreated hair ... 0 points,
Same as untreated hair ... 1 point,
Softer than untreated hair ... 2 points
Compared to untreated hair, it is quite soft ... 3 points.

  Furthermore, about each evaluation result, the average value of the score of all the panelists was calculated | required, and the elongation of the hair which concerns on each test hair bundle after a process, the stickiness of a hair tip, and softness were determined according to the following reference | standard.

(Hair elongation)
0 points or more and less than 1.6 points: not stretched,
1.6 points or more: Stretched.

(Dust attached to the hair ends)
0 points or more and less than 2.2 points:
2.2 points or more and less than 2.6 points: hardly sticking,
2.6 or more: Not sticking.

(Softness of hair)
0 points or more and less than 2 points: Does not feel soft,
2 points or more and less than 2.4 points: soft,
2.4 or higher: Pretty soft.

  Among these results, when the heating temperature by the straight hair iron is 180 ° C. (Comparative Examples 1 to 18) is shown in Table 4, and when 200 ° C. (Comparative Examples 19 to 36) is shown in Table 5, 230 ° C. Table 6 shows the cases (Comparative Examples 37 to 41 and Examples 1 to 13).

  As shown in Tables 4 to 6, according to the hair deformation treatment method of Examples 1 to 13 in which a one-component hair treatment agent having an appropriate composition and pH was used and heating with a hair straightener was performed at an appropriate temperature. For example, the hair after the treatment has good elongation, a good straight shape, and the tip of the hair is prevented from sticking. Moreover, the hair after the treatment by the hair deformation treatment method of Examples 1 to 13 has good softness.

  On the other hand, in the hair deformation treatment method of Comparative Examples 1-36 in which the heating temperature by the straight hair iron is not suitable, the elongation of the hair after the treatment is particularly insufficient and a good straight shape cannot be obtained. In addition, some of the hairs after the treatment by these treatment methods are dusty or inferior in softness.

  On the other hand, although the heating temperature with a straight hair iron is appropriate, a one-component hair treatment agent containing a reducing agent used in a normal hair straightener instead of sulfite or bisulfite was used. In the hair deformation treatment methods of Comparative Examples 37 to 39, although the elongation of the hair after the treatment was good, the hair tips were stuck.

  In addition, among the hair deformation treatment methods of Comparative Example 40 and Comparative Example 41 using a one-component hair treatment agent having an appropriate pH but an inappropriate pH, the one-component method in which the pH is too low. In the case of the hair deformation treatment method of Comparative Example 40 using the hair treatment agent, the hair deformation after treatment is insufficient, and the hair deformation of Comparative Example 41 using the one-component hair treatment agent having a pH that is too high. In the case of the treatment method, the hair ends after the treatment are stuck.

Experiment 2: Measurement of the amount of disulfide bonds in hair after treatment with a one-part hair treatment agent As a one-part hair treatment agent, a 4% concentration aqueous sodium sulfite solution (pH 8.0, Preparation Example 19) and a 7% concentration Using an aqueous ammonium thioglycolate solution (pH 9.2, Preparation Example 20), the amount of disulfide (S—S) bonds in the hair treated with these was determined as a residual ratio (hereinafter referred to as “S—S bonds”) of untreated hair. It was calculated as “remaining rate of SS bond amount relative to untreated hair”).

  The hair treatment was performed in the same manner as in Experiment 1 except that the one-component hair treatment agent of Preparation Example 19 was used, and the sample (1), which was not heated with a straight hair iron, straight A sample (2) that was heated at 180 ° C. with a hair iron for heating and a sample (3) that was heated at 230 ° C. with a hair iron for straight were prepared. Moreover, also about the 1 agent type hair treatment agent of the preparation example 20, the sample (4) processed using the same method as Experiment 1 except not having performed the heat processing by the hair curling iron for straight, this 1 agent type hair Sample (5), which was treated in the same manner as in Experiment 1 except that the treatment agent was used, and heated with a straight hair iron at 180 ° C., was treated in the same manner as Sample (5), and then sodium bromate was used. Sample (6) subjected to oxidation treatment was produced.

  Then, the S—S bond amount of each sample and untreated hair was determined as follows using polarography.

  In this measurement, only the S—S bond amount cannot be directly measured, so the total amount of the S—S bond and the S—H bond is once measured, and the separately measured S—H bond amount is excluded from this value. Thus, the S—S bond amount was determined.

  A measurement sample of the total amount of S—S bonds and S—H bonds was prepared as follows. Urea: 240.24 g, ammonium chloride: 4.279 g, potassium chloride: 18.6375 g, sodium sulfite: 12.604 g and gelatin: 0.05 g were weighed into a 500 mL beaker, and purified water: 400 mL was added thereto. This was heated to 70 ° C. to dissolve gelatin, aqueous ammonia was added to adjust pH to 9.3, and further purified water was added to make 500 mL, followed by transfer to a brown bottle. Next, 0.1712 g of methylmercury iodide: 0.1712 g was added to this brown bottle and dissolved by stirring to prepare a measurement reagent, which was stored at 4 ° C. Seven measurement reagents were prepared, and each of the samples (1) to (6) and 10 mg of untreated hair were put in separate measurement reagents to obtain measurement samples.

  Moreover, the measurement sample of the amount of S—H bonds was prepared as follows. A phase consisting of trishydroxymethylaminomethane buffer (100 mL, 0.1 M, pH 7, and 0.1 M KCl added) and B phase consisting of an aqueous gelatin solution (25 mL, 0.25% concentration) , Potassium chloride: 500 mL of purified water was added to 3.73 g, 2.5 mL was taken out from this, and 2.5 mL of methylmercuric iodide solution (0.1 M dimethylformamide solution) was added, Were mixed and stirred to prepare a measuring reagent, which was then placed in a brown bottle and stored at 4 ° C. Seven measurement reagents were prepared, and each of the samples (1) to (6) and 40 mg of untreated hair were put in separate measurement reagents to obtain measurement samples.

  The total amount of S—S bond and S—H bond in the measurement sample of the total amount of S—S bond and S—H bond, and the amount of S—H bond in the measurement sample of the S—H bond amount were measured by YANACO Measurements were made using “DEOXYGEN STAND DS-100 (trade name)”, “POLALOGRAPHIC ANALYZER P-3000 (trade name)”, and “dropping mercury electrode stand P-1000ST (trade name)”. For each of the samples (1) to (6) and the untreated hair, the amount of S—H bonds is removed from the total amount of S—S bonds and S—H bonds, and the samples (1) to (6). The residual ratio (%) of the S—S bond amount to the S—S bond amount of the untreated hair was calculated. These results are shown in Table 7.

  As shown in Table 7, the hair treated with the one-part hair treatment agent of Preparation Example 20 containing thioglycolate (ammonium thioglycolate), which is widely used as a reducing agent for general hair straighteners, The amount of S—S bonds was decreased before heating with a hair iron for straight [Sample (4)] and after heat treatment at 180 ° C. [Sample (5)], and the reduction of S—S bonds was caused by reduction. I understand that It can also be seen that the amount of S—S bonds is increased by the treatment [sample (6)] with an oxidizing agent, and the S—S bonds are reformed. The treatment in sample (6) corresponds to treatment with a two-component hair straightener, but from these results, in the case of a hair treatment agent using a general reducing agent, the amount of S—S bonds in the hair is increased. It can be seen that treatment with an oxidant is necessary to obtain a state equivalent to that in the untreated state.

On the other hand, with hair treated with the one-component hair treatment agent of Preparation Example 19 prepared with sodium sulfite and having a pH of 8.0, before heating with a straight hair iron, after heating at 180 ° C., 230 ° C. It can be seen that the S—S bond amount is almost the same as that of the untreated hair even after the heating at, and almost no cleavage of the S—S bond due to the reduction occurs. For this reason, in the treatment using the one-component hair treatment agent of Preparation Example 19, ie, the one-component hair treatment agent containing the sulfite or bisulfite and adjusting the pH to an appropriate value, Straightness is imparted to the hair by a mechanism different from the treatment using a hair treatment agent containing a reducing agent (corresponding to the first agent in a general two-part hair straightener). Is guessed. Further, from the above results, in the one-component hair treatment agent (one-component hair treatment agent of Preparation Example 19) containing sulfite or bisulfite and having an appropriate pH, the SS bond amount is It can also be seen that the oxidation treatment for returning to the untreated hair state is unnecessary.

Claims (8)

A step (I) of applying, to the hair, a one-component hair treatment agent having a pH of 6 to 10 in which at least one sulfite or bisulfite and dithiodiglycolate are blended;
The hair having the step (II) of imparting straightness to the hair by applying heat to the hair with a hair straightener having a surface temperature of 230 to 250 ° C. after the step (I) Deformation processing method.   The hair deformation treatment method according to claim 1, further comprising a step of washing the hair with water between the step (I) and the step (II).   The hair deformation treatment method according to claim 2, further comprising a step of drying the hair between the step of washing the hair with water and the step (II).   The hair deformation treatment method according to any one of claims 1 to 3, wherein a blending amount of sulfite or bisulfite in the one-agent hair treatment agent is 0.5 to 10% by mass.   The hair deformation treatment method according to any one of claims 1 to 4, wherein the sulfite in the one-component hair treatment agent is sodium sulfite.   The hair deformation treatment method according to any one of claims 1 to 4, wherein the bisulfite salt in the one-component hair treatment agent is sodium bisulfite. The hair deformation treatment method according to any one of claims 1 to 6 , wherein the amount of dithiodiglycolate in the one-component hair treatment agent is 0.5 to 10% by mass. The hair deformation treatment method according to any one of claims 1 to 7 , wherein the one-component hair treatment agent further contains a water-soluble polymer.