JPH04224508A - Hair cosmetic - Google Patents

Abstract

PURPOSE:To provide the title cosmetic capable of preventing hair injuries such as hair reddening due to ultraviolet radiation, decline in combing smoothness and hair stiffness, containing a combination a high-polymerization degree dimethylpolysiloxane and a specific ultraviolet light absorber. CONSTITUTION:The objective cosmetic containing a combination of (A) a high- polymerization degree dimethylpolysiloxane of formula I (n is 500-8000) and (B) as ultraviolet absorber, a octyl p-methoxycinnamate and/or a benzophenone of formula II (R1 and R3 are each H or OH; R2 and R4 are each H, OH or methoxy) (e.g. dihydroxydimethoxybenzophenone). The contents of the components A and B in the cosmetic are as follows: A=0.5-50 (pref. 1-30)wt.%; B=0.1-20 (pref. 0.5-10)wt.%.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to hair cosmetics, and more particularly to hair cosmetics that prevent hair damage caused by ultraviolet rays, such as reddening of hair, poor combability, and stiff feeling.

0002

BACKGROUND OF THE INVENTION In recent years, with changes in lifestyles such as an increase in leisure time, the number of people playing sports and enjoying leisure is increasing year by year, and summer sea swimming and year-round marine sports are attracting attention. However, while playing these sports, the hair is exposed to strong sunlight and sea water,
Hair is damaged by these.

[0003] This hair damage is thought to be caused by a combination of the alkaline nature of seawater with a pH of around 8 and the ultraviolet rays in the sun.
Examples include denaturation of hair proteins, poor combability, and stiff feeling.

[0004] As a method for preventing such hair damage, cosmetics generally contain ultraviolet absorbers and titanium oxide. For example, Japanese Patent Application Laid-Open No. 61-229809,
JP-A No. 62-84017 contains fine-particle titanium oxide to provide a sun protection effect, but when used on the hair, the hair becomes white and powdery, making it unusable for practical use. It wasn't something. Furthermore, the ultraviolet absorber and fine titanium particles that adhered to the hair were easily washed away by seawater and sweat, and no long-lasting effects were observed.

[0005] Furthermore, JP-A-1-211515 proposes a hair cosmetic containing a polymeric silicone and an antioxidant such as tocopherol, but it causes problems such as reddening of hair and denaturation of hair proteins. It was not effective enough to prevent hair damage and could not be put to practical use.

[0006]

[Problems to be Solved by the Invention] As a result of intensive research to develop a hair cosmetic that improves the problems and drawbacks of the prior art, the present inventors found that, among ultraviolet absorbers, octyl p-methoxycinnamate, in particular, By using benzophenones and/or benzophenones in combination with highly polymerized dimethylpolysiloxane, hair damage such as hair redness, denaturation of hair proteins, poor combability, and stiff feeling can be prevented, and water repellency can be achieved. The present inventors have discovered that it is possible to obtain a hair cosmetic with excellent long-lasting effects that is not washed away by seawater or sweat, and has completed the present invention.

[0007]

[Means for Solving the Problems] That is, the present invention provides (a) general formula

One or more highly polymerized dimethylpolysiloxanes represented by (n represents an integer of 500 to 8,000);

(b) Octyl paramethoxycinnamate and/or general formula

[Chemical formula 4] (R1 and R3 represent hydrogen or a hydroxy group,
R2 and R4 represent hydrogen, hydroxy group or methoxy group. ) is a hair cosmetic characterized by containing benzophenones represented by:

The value of n in the formula of the highly polymerized dimethylpolysiloxane used in the present invention is about 500 to 8,000, and the viscosity at 25° C. is 1,000 to 1,000,000 centistokes. Its content is 0.0% in the total amount of hair cosmetics.
It is 5 to 50% by weight, preferably 1 to 30% by weight. If it is less than 0.5% by weight, sufficient effects cannot be obtained, and if it exceeds 50% by weight, it becomes difficult to dissolve and becomes sticky during use.

When the highly polymerized dimethylpolysiloxane of the present invention is blended into a hair cosmetic, it is preferably dissolved in a volatile oil that can dissolve the highly polymerized dimethylpolysiloxane. Examples include boiling point cyclic silicone, low boiling point chain silicone, and low boiling point isoparaffin having 1 to 300 carbon atoms.

Octyl paramethoxycinnamate of the present invention,
Benzophenones may be used alone or in combination. Preferably, the benzophenones are oil-soluble, and include dihydroxydimethoxybenzophenone, dihydroxybenzophenone, tetrahydroxybenzophenone, oxybenzone, and the like. Its content is 0.1-20% by weight, preferably 0.5-1
It is 0% by weight. If the amount is less than 0.1% by weight, the desired UV protection effect will not be noticeable, so it is necessary to add 0.5% by weight or more. Not good.

In addition to the above-mentioned essential ingredients, the hair cosmetic of the present invention may contain alcohol, a solvent, an emulsifier, an oily component, a preservative, and a pH value within a range that does not impair the effects of the present invention, depending on the purpose.
Conditioners, fragrances, stabilizers, vitamins, hormones, aerosol propellants, etc. can be added.

[0013]

[Examples] The present invention will be explained in more detail below with reference to Examples. The contents of the compositions shown in the following formulations and tables are expressed in weight percent.

Example 1, Comparative Example 1 0.5 g of hair oil having the composition shown in Table 1 (nothing was applied in Comparative Example 1) was evenly applied to a hair strand with a length of 15 cm and a weight of 3 g. After combing through the hair to blend it all over the hair, immerse it in 500ml of seawater and stir for 30 minutes. The hair was then taken out of the seawater and irradiated with ultraviolet light.

[0015]

[Table 1]

[0016] Ultraviolet rays were irradiated using a weather meter (manufactured by Suga Test Instruments Co., Ltd.) using a sunshine carbon arc as a light source.
Then, it was irradiated with ultraviolet light at a dose of 500 J/cm2, thoroughly washed with a commercially available shampoo, and dried.

[0017]Furthermore, the above operations (applying hair oil, dipping in seawater, irradiating with ultraviolet rays, washing with shampoo) were repeated until the total amount of ultraviolet rays reached 4500 J/cm2, and finally, after washing with shampoo, washing with water was performed. ，Dried.

Next, the effect of preventing hair damage such as hair redness, protein denaturation, combability, stiffness, etc. was evaluated using the evaluation method shown below, and the results are shown in Table 2.

(1) Effect of preventing redness of hair The color of the hair after irradiation with ultraviolet rays was measured using a high-speed colorimeter (manufactured by Murakami Shikizai), and the tristimulus values X, Y, and Z were measured using a Hunter.
Convert to the Lab color system and calculate the difference Δ from the hair before UV irradiation.
L, Δa, and Δb were determined, and the color difference ΔE was calculated using the following formula. Note that the smaller the color difference ΔE, the higher the red color prevention effect.

Color difference ΔE={(ΔL)2+(Δa)2+(
Δb)2}1/2

(2) Combing the hair In order to examine the ease of combing the hair, 20 hairs were taken out from the hair after UV irradiation and their dynamic friction coefficient (μK) was measured using a radar friction meter. The measurement result is hair 20
Shown as the average value of books. In addition, the smaller the value of the dynamic friction coefficient,
It means that it combs well.

(3) Effect of preventing hair protein denaturation In order to examine the effect of preventing protein denaturation, the degree of hair protein denaturation (cystine damage rate) was measured as follows.

10 mg of hair before and after irradiation with ultraviolet rays and 2 ml of 6N hydrochloric acid are placed in a glass ampoule, the atmosphere in the ampoule is replaced with nitrogen, and after the tube is sealed, hydrolysis is carried out at 110° C. for 24 hours. Next, the hydrolysis reaction product was taken out and evaporated to dryness, then dissolved in 40 ml of 0.02N hydrochloric acid, and the amounts of cysteic acid and cystine were measured using an amino acid automatic analyzer (manufactured by Hitachi). Cystine damage rate (%) was calculated according to the formula.

[0024]

[Math 1]

[0025] The cystine damage rate before UV irradiation was 3.5%.

(4) Stiffness of hair In order to examine the degree of stiffness of hair, 10 professional examiners were asked to perform a sensory evaluation based on the following criteria in comparison with hair before ultraviolet irradiation.

- I felt that my hair was stiff. ;A: I did not feel that my hair was stiff. ;B results are shown by the number of people who answered B.

[0028]

[Table 2]

As is clear from Table 2, the hair cosmetic of the present invention (Example 1) exhibited excellent hair damage prevention effects. On the other hand, when nothing is applied (Comparative Example 1), hair damage such as reddening of the hair, protein denaturation, poor combability, and stiff feeling is severe.

Examples 2 to 4, Comparative Examples 2 to 7 Nine types of hair cosmetics whose compositions are shown in Table 3 were irradiated with ultraviolet rays in the same manner as in Example 1, resulting in hair redness, combability, and protein denaturation. We evaluated the effect of preventing hair damage such as stiffness and stiffness. The results are listed in the same table.

[0031]

[Table 3]

As a result, as is clear from Table 3, the hair cosmetics of the present invention containing one or more of octyl para-methoxycinnamate and benzophenones and highly polymerized dimethyl polysiloxane (Examples 2 to 4) All had excellent properties and good results were obtained.

On the other hand, hair cosmetics not containing highly polymerized dimethylpolysiloxane (Comparative Example 2), or hair cosmetics not containing octyl para-methoxycinnamate and benzophenones (Comparative Example 3), Fine particle titanium oxide (
Comparative Example 4), tocopherol (Comparative Example 5), octyl para-aminodimethylbenzoate, 4-t as a UV absorber
ert-4'-methoxydibenzoylmethane (Comparative Example 6
Hair cosmetics containing 7) are inferior in hair damage prevention effects in all respects.

Example 5 A hair foam consisting of the formulation shown in Table 4 was prepared and
The same treatment and evaluation were performed.

[0035]

[Table 4]

Production method ① to ③ were stirred and mixed at 80°C, and ① to ③ were added to the dissolved solution to emulsify to obtain a stock solution. Next, 5 parts of a propellant consisting of LPG were added to 95 parts of this stock solution, and the mixture was filled into a spray can.

Comparative Example 8 The same procedure as in Example 5 was repeated except that octyl paramethoxycinnamate was not used and 0.5% by weight of alcohol was added.

Example 6 A hairspray having the formulation shown in Table 5 was prepared and
The same treatment and evaluation were performed.

[0039]

[Table 5]

[0040] Production method 1 to 2 are stirred and mixed to prepare a stock solution. To 20 parts of the stock solution, 80 parts of a propellant consisting of LPG was added and filled into a spray can.

Comparative Example 9 In Example 6, dihydroxybenzophenone was not used, and decamethylcyclopentasiloxane was used in 5.
The same procedure as in Example 6 was carried out except that 0% by weight was added.

Example 7 A hair cream having the formulation shown in Table 6 was prepared.
The same treatment and evaluation were performed.

[0043]

[Table 6]

Production methods (i) to (viii) are dissolved and stirred at 80°C (solution 1
). (ix) and (xi) are dissolved and stirred at 80°C (solution 2). Next, Solution 2 is added to Solution 1 and emulsified, and (x) is added at 60° C. and cooled to room temperature.

Comparative Example 10 Example 7 except that highly polymerized dimethylpolysiloxane was not used and 5.0% by weight of petrolatum was added.
The same procedure as in Example 7 was carried out.

Example 8 A hair blower was prepared according to the formulation shown in Table 7, and treated and evaluated in the same manner as in Example 1.

[0047]

[Table 7]

Production method (1) to (2) were uniformly stirred and dissolved, and then (2) was added to obtain a hair blow.

Comparative Example 11 The same procedure as in Example 8 was conducted except that oxybenzone was not used and 0.2% by weight of ascorbic acid (antioxidant) was added.

Example 9 A setting lotion consisting of the following formulation was prepared, and Example 1
The same treatment and evaluation were performed.

[0051]

[Table 8]

Production method (1) to (2) were uniformly mixed and dissolved, then (2) was added and mixed uniformly to obtain a setting lotion.

Comparative Example 12 In Example 9, octyl p-methoxycinnamate and oxybenzone were not used, and 1.0% by weight of 2,6-di-t-butyl-p-cresol (antioxidant) was used. The same procedure as in Example 9 was carried out except for the addition.

Table 9 shows the results of evaluating the hair damage prevention effects of the products of the present invention obtained in Examples 5 to 9 and the conventional products obtained in Comparative Examples 8 to 12.

[0054]

[Table 9]

As is clear from Table 9, the product of the present invention has excellent effects on preventing hair damage, such as preventing hair redness, preventing protein denaturation, preventing poor combability, and preventing stiff feeling. Ta.

[0056]

[Effects of the Invention] The present invention exhibits a useful and remarkable effect of preventing hair damage such as reddening of hair, denaturation of hair proteins, poor combability, and stiff feeling, and is highly water repellent. To provide a useful hair cosmetic that maintains its effect without being washed away by seawater or sweat.

Claims (1)

[Claims] Claim 1: (a) one or more highly polymerized dimethylpolysiloxanes represented by the general formula [Formula 1] (n represents an integer from 500 to 8,000); (b) paramethoxy Octyl cinnamate and/or general formula [Formula 2] (R1 and R3 represent hydrogen or a hydroxy group,
R2 and R4 represent hydrogen, hydroxy group or methoxy group. ) A hair cosmetic characterized by containing a benzophenone represented by: