KR19980076283A - Method for preparing zinc pyrithione suspension and hair composition using same - Google Patents

Abstract

The present invention relates to a method for preparing a suspension capable of improving the anti-dandruff effect and stability in a product of zinc pyrithione suspension which has been widely used as an anti-dandruff agent in hair compositions such as shampoo and rinse.

According to the preparation method of the present invention, to prepare a zinc pyrithione suspension by reacting a sodium pyrithione solution and zinc salt (ZnCl _2, ZnSO ₄ · 7H ₂ O, etc.), tocopheres (nonionic surfactant) ( Tocophereth (a nonionic surfactant in which the hydroxyl group of vitamin E is ethoxylated) can be used to increase the anti-dandruff effect by miniaturizing the particle size, and also to add other components in the hair composition, such as cationic surfactants or cationic polymers. It can also improve the compatibility with the product can improve the stability of the product.

Description

Method for preparing zinc pyrithione suspension and hair composition using same

The present invention relates to a method for preparing a zinc pyrithione suspension, and more particularly, it is possible to increase the anti-dandruff effect by miniaturizing the particle size of zinc pyrithione and to improve compatibility with other components in the hair composition. It relates to a method for producing a zinc pyrithione suspension. Furthermore, the present invention relates to a hair composition having an excellent anti-dandruff effect and elevated product stability by containing a zinc pyrithione suspension provided by the preparation method of the present invention.

In general, dandruff refers to the stratum corneum-like mass formed by the dead or peeled cells of the scalp caused by the active metabolism of the human body with the secretion of the scalp sebaceous glands. Dandruff gradually has a clear border with normal skin, becomes red, and increases the scale of the scalp, which usually leads to seborrheic dermatitis with itching and inflammation.

The root cause of dandruff development is not yet clear, but in general, neurological factors such as endocrine hormone imbalance, metabolic imbalance, stress, biochemical changes in epithelial tissue due to excessive proliferation of scalp cells, and scalp It is known to be due to a complex effect of several factors such as the growth and activity of microorganisms, inflammation caused by air pollution.

In particular, the proliferation and activity of microorganisms called Pityrosporum Ovlae present in unclean scalp have been recognized for a long time as a major factor for worsening dandruff and itching, and are widely accepted in recent years.

Therefore, in the case of hair cosmetic having an anti-dandruff effect for the treatment and prevention of dandruff and itching, it effectively inhibits the growth and activity of microbial phytirosporum obale, which is the main cause of dandruff, and abnormal metabolic activity of the scalp cells. It is an essential requirement to contain the component which can normalize the

Thus, as an example of the hair cosmetic composition aimed at suppressing dandruff and itching, a shampoo composition containing zinc pyrithione (zinc-2-pyridinechiol-1-oxide) as an active ingredient is mentioned. Patent 2,809,971, US Patent 4,323,683, US Patent 4,345,080, US Patent 4,470,982, and European Patent 285,388. However, zinc pyrithione is a water-insoluble solid particle having a spherical form of 0.3-10 μm particle size having a very low limit of solubility of only 15 ppm in water at 25 ° C. In the shampoo composition has a number of disadvantages in the usability caused by the separation phenomenon by precipitation.

Accordingly, in order to prevent separation in the composition, zinc pyrithione is used as a protective colloid to stabilize the suspension using 0.1 to 5% by weight of an anionic polymer such as sodium polynaphthalene sulfonate, cellulose gum, and the like. It is manufactured and marketed with the aqueous 48-50% solution.

However, when a zinc pyrithione suspension using an anionic polymer as a suspending stabilizer is used in hair compositions such as shampoo and rinse, cationic surfactants or cationic polymers and negative-cationic ions which are widely used to give a conditioning effect are used. Not only is the stabilization of the product very poor by forming an insoluble salt, but also has a problem that the anti-dandruff effect is also reduced.

Accordingly, the present inventors react with zinc pyrithione by reacting sodium pyrithione with zinc salts such as zinc chloride (ZnCl ₂ ) and zinc sulfate (ZnSO ₄ · 7H ₂ O), as represented by Scheme 1 below. In the preparation, it is possible to refine the particle size of the zinc pyrithione produced by the appropriate addition of Tocophereth represented by the following formula (1), when contained in the hair composition, other components in the composition, such as For example, the present invention has been found to increase the compatibility with cationic commanding agents or cationic polymers.

[Scheme 1]

[Formula 1]

Wherein R _{1 and} R ₂ are H or -CH ₃ and n is an integer from 5 to 50

Accordingly, it is an object of the present invention to prepare a zinc pyrithione suspension by reacting sodium pyrthione with a zinc salt, to prepare a suspension of zinc pyrithione capable of miniaturizing the particle size of the zinc pyrithione produced. To provide a way.

Furthermore, another object of the present invention is to provide a hair composition having a zinc pyrithione suspension provided by the present invention with excellent anti-dandruff effect and elevated product stability.

The method for producing zinc pyrithione according to the present invention is characterized in that an appropriate amount of tocopheres of formula (1), which is a nonionic surfactant, is reacted in the reaction between sodium pyrithione and zinc salt.

The zinc salt used in the production method of the present invention is not particularly limited, and conventionally used in the preparation of zinc pyrithione suspensions can be used, for example zinc chloride (ZnCl ₂ ), zinc sulfate (ZnSO ₄ 7H ₂ O), and the like.

Tocopheres characterized by the present invention is a nonionic surfactant in which the hydroxyl group of vitamin E is ethoxylated, and among the polyethoxylated vitamin E known in the art, CH ₂ CH ₂ CH = CCH ₃ ) ₃ CH ₃ It is a compound containing a substituent. In the preparation method of the present invention, tocopheres are added in an amount of 0.01 to 10% by weight based on the total weight of the reactants.

The zinc pyrithione suspension provided by the preparation method of the present invention can improve the stability of the composition by excellent compatibility with other components in the hair composition such as shampoo and rinse, in particular cationic surfactant or cationic polymer. . This is because tocopheres is nonionic, and therefore, it is excellent in compatibility with the cationic surfactant used for the purpose of imparting a conditioning effect, compared with the case of using an anionic polymer as a conventional suspension stabilizer.

In addition, the hair composition containing the zinc pyrithione suspension provided by the present invention exhibits a synergistic effect in the anti-dandruff effect, since the particle size of the resulting zinc pyrithione is small and the permeability to the scalp is increased. to be. This increased anti-dandruff effect is demonstrated in the test examples described below.

The hair composition according to the present invention is characterized in that it contains a zinc pyrithione suspension provided by the method of the present invention for the purpose of preventing dandruff in an amount of 0.01 to 2.0% by weight based on the total weight of the composition.

The hair composition of the present invention may have a conventional formulation and may be formulated, for example, as a shampoo, rinse, hair conditioner, hair tonic, hair treatment, and the like. The composition of each of these formulations may contain a variety of bases and additives necessary for the formulation of the formulation and are suitable, and the types and amounts of these components can be readily selected by those skilled in the art.

Hereinafter, representative base components and additives will be described taking representative shampoo compositions of the hair cosmetic composition as examples.

For example, in the case of a shampoo formulation, in the present invention, a shampoo composition composed of a synthetic surfactant, pearlescent aid, preservative, thickener and viscosity adjusting agent, pH adjusting agent, fragrance, dye, hair conditioning agent and water, which is a cleaning ingredient, Synthetic surfactants used include 10 to 70% by weight of the surfactant, preferably 10 to 30% by weight of the composition, which may be any of anionic, amphoteric, nonionic and cationic surfactants, 0.01 to 10% by weight, preferably 0.1 to 5% by weight.

Hereinafter, the structure and effect of the present invention will be described in more detail based on Examples and Test Examples.

Example 1

To 745 g of 40% aqueous sodium pyrithione solution, 20 g of tocopheres (EO = 50) was added to dissolve completely, and then vigorously stirred with 287 g of zinc sulfate (ZnSO ₄ · 7H ₂ o), followed by 48% zinc pyrithione. Suspension was prepared.

Example 2

After adding 20 g of tocopheres (EO = 10) to 745 g of 40% aqueous solution of sodium pyrithione, completely dissolving it, and then stirring vigorously while adding 287 g of zinc sulfate (ZnSO ₄ · 7H ₂ o), a 48% zinc pyrithione suspension was added. Was prepared.

Test Example 1

The particle size of the zinc pyrithione suspension prepared in the present invention and the commercially available zinc pyrithione suspension was measured with a Malvern master sizer. The results are shown in Table 1.

TABLE 1

Particle size distribution of zinc pyrithione suspension

Examples 3-6 and Comparative Examples 1-2

In order to verify the improvement of the anti-dandruff effect and the stability of the zinc pyrithione suspension prepared in the above examples, the following shampoo, rinse system was applied.

TABLE 2

Shampoo, rinse composition with zinc pyrithione suspension

Test Example 2 Antidandruff Effect Experiment

Antidandruff effect is measured by the Skin Disc Diffusion Method. First, the test bacteria were streaked on agar plates, and cultured for 2 days dandruff causative organism of Pitti Los form Ovalle to 37 ℃ under aerobic conditions. After sterilizing the skin disk with 70% ethanol, the shampoos of Comparative Examples 1 and 3 and 4 and the rinses of Comparative Examples 2 and 5 and 6 were diluted 10-fold and washed with purified water. The treated skin disks were placed on an agar plate, and the inhibition zones (Inhibition Zones) were measured and repeated three times after 48 hours at 37 ° C. This zone is the size of the radius (mm) excluding the size of the skin disc.

TABLE 3

Inhibition Zones (mm)

Test Example 3 Dandruff Reduction Effect Test

Forty-eight males aged 19 to 48 with relatively high dandruff were selected and tested for six months in six groups of eight for each of the comparative and example shampoos, and the results are shown in Table 4.

Before the start of the test, trituration (rinse) with a normal shampoo (rinse), and collected the dandruff accumulated for three days after the tribal (rinse), the weight of the collected dandruff, and the shampoo (rinse) of each Example and Comparative Example Three times (rinse) once a day to evaluate the weight of the dandruff accumulated for 3 days after the end of the test. At this time, the accumulated dandruff was collected directly from the scalp with a vacuum suction device, and the dandruff reduction rate was calculated based on the following equation.

[Equation 1]

Dandruff Reduction (%) =

{Weight of mg dandruff before test start-mg of dandruff 1 month after test start}

───────────────────────────────────── # 12316; ────────── ────────────────────── × 100

{Weight of mg dandruff before test start}

TABLE 4

Comparison of effects of dandruff reduction rate (%)

From the results of the above test, the rate of dandruff reduction was significantly higher than that of the shampoo and rinse of the example prepared using the zinc pyrithione suspension according to the present invention, and the shampoo and rinse of the comparative example prepared using the commercially available zinc pyrithione suspension. It can be seen that high.

Test Example 4 Stability Improvement Effect Experiment

The shampoo and rinse products prepared to check the stability of the shampoo and rinse products were put in 70 ml of clear glass containers (100 ml capacity), respectively, and stored in a constant temperature bath at 50 ° C. for the visual observation of the product stability. The results are shown in Table 5.

TABLE 5

Results of comparing the stability of shampoo and rinse products (50 ℃, stored for 1 month)

From the results of the above test, it can be seen that the stability of the shampoo and rinse prepared using the conventional zinc pyrithione suspension is much worse than the shampoo and rinse prepared using the zinc pyrithione suspension according to the present invention.

From the above test examples, the zinc pyrithione suspension provided by the present invention exhibits a finer particle size than the zinc pyrithione suspension prepared by using a commercially available anionic polymer as a suspension stabilizer, and has an excellent anti-dandruff effect. It is evident that the product is significantly improved in terms of stability.

Claims (2)

In preparing zinc pyrithione by reacting sodium pyridion and zinc salt, Tocophereth represented by the following Chemical Formula 1 is added in an amount of 0.01 to 10% by weight based on the total weight of the reactant. Preparation method of zinc pyrithione suspension [Formula 1] Wherein R _{1 and} R ₂ are H or -CH ₃ and n is an integer from 5 to 50 A hair composition comprising the zinc pyrithione suspension prepared by the method according to claim 1 in an amount of 0.01 to 2.0% by weight based on the total weight of the composition.