Drug – bio-affecting and body treating compositions – Live hair or scalp treating compositions – Polymer containing
Reexamination Certificate
1999-07-02
2001-06-19
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Live hair or scalp treating compositions
Polymer containing
C424S070100, C424S401000, C008S405000, C008S435000, C008S552000, C008S562000, C008S611000, C008S613000
Reexamination Certificate
active
06248314
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a hair dye composition which is excellent in hair-dyeing ability without coloring the scalp and skin and has good fastness to shampoo.
BACKGROUND ART
Acid hair dye compositions (for example, Japanese Patent Application Laid-Open Nos. 210023/1986 and 101841/1995, etc.) comprising various kinds of organic solvents represented by benzyl alcohol as a penetrant solvent have good penetrability into hair, but have involved such problems that they color the scalp and skin at the same time as hair coloring.
In order to prevent the skin from being colored, it has been conducted to reduce coloring to the skin by thickening a hair dye composition with a water-soluble polymer or the like to prevent the drooping of the hair dye composition (Japanese Patent Application Laid-Open Nos. 87450/1998, 255540/1997 and 245348/1996). However, this method has failed to essentially improve the hair dye composition. The lowering of skin-coloring tendency by analogous compounds of aromatic alcohols, lower alkylene carbonates, or the like (Japanese Patent Application Laid-Open No. 53970/1998 and Japanese Patent Publication No. 23911/1973) has also been unsatisfactory.
SUMMARY OF THE INVENTION
The present inventors have found that when an alkylene carbonate is incorporated as a penetrant solvent into an acid system containing an acid dye, and the buffer capacity of the resulting composition is adjusted to a specific range, a hair dye composition, which is excellent in hair-dyeing ability while inhibiting coloring to the skin and has good fastness to shampoo, can be obtained.
According to the present invention, there is thus provided a hair dye composition which comprises (A) an acid dye and (B) an alkylene carbonate having 3-5 carbon atoms in total, said composition exhibiting a pH of 2-6, and having a buffer capacity of 0.007-0.5 gram equivalent/L.
According to the present invention, there is also provided a method of dyeing hair which comprises applying the above hair dye composition to hair, allowing the hair to stand, washing the hair by use of a shampoo and then drying the hair.
BEST MODE FOR CARRYING OUT THE INVENTION
No particular limitation is imposed on the acid dye of the component (A) used in the present invention so far as it is a water-soluble acid dye. Examples thereof include Red Color No. 120, Yellow Color No. 4, Yellow Color No. 5, Red Color No. 201, Red Color No. 227, Orange Color No. 205, Brown Color No. 201, Red Color No. 502, Red Color No. 503, Red Color No. 504, Red Color No. 506, Orange Color No. 402, Yellow Color No. 402, Yellow Color No. 406, Yellow Color No. 407, Red Color No. 213, Red Color No. 214, Red Color No. 3, Red Color No. 104, Red Color No. 105(1), Red Color No. 106, Green Color No. 2, Green Color No. 3, Orange Color No. 207, Yellow Color No. 202(1), Yellow Color No. 202(2), Blue Color No. 202, Blue Color No. 203, Blue Color No. 205, Blue Color No. 2, Yellow Color No. 203, Blue Color No. 201, Green Color No. 201, Blue Color NO. 1, Red Color No. 230(1), Red Color No. 231, Red Color No. 232, Green Color No. 204, Green Color No. 205, Red Color No. 401, Yellow Color No. 403(1), Green Color No. 401, Green Color No. 402, Black Color No. 401 and Purple Color No. 401.
These acid dyes may be used either singly or in any combination thereof and are preferably incorporated in a proportion of 0.001-5% by weight (hereinafter indicated merely by “%”), particularly 0.005-4%, more particularly 0.2-3% based on the total weight of the composition, from the viewpoint of practical use in that a sufficient hair-dyeing effect is achieved, and the hand skin is scarcely smeared.
The component (B) used in the present invention includes ethylene carbonate, propylenecarbonate and the like, with propylene carbonate being particularly preferred.
The component (B) is preferably incorporated in a proportion of 0.5-50%, more preferably 5-50%, particularly 10-40% based on the composition of the present invention, from the viewpoints of hair-dyeing ability and anti-coloring property to the skin.
The hair dye compositions according to the present invention must have a pH of 2-6, preferably 2-5, more preferably 2.5-4.0. If the pH is too low, the resulting composition may roughen the hair, scalp and hand skin due to an acid component in some cases. If the pH is too high, the penetration accelerating effect on the acid dye is lowered.
The hair dye compositions according to the present invention must also have a buffer capacity of 0.007-0.5 gram equivalent/L as measured in the form of a 10% aqueous solution of the composition. The buffer capacity is preferably not lower than 0.007 gram equivalent/L, but lower than 0.2 gram equivalent/L, more preferably not lower than 0.01 gram equivalent/L, but lower than 0.2 gram equivalents/L, most preferably not lower than 0.015 gram equivalent/L, but lower than 0.2 gram equivalent/L. The buffer capacity in the present invention means a value determined by using, as a measure, the concentration of a base required to raise the pH of a 10% aqueous solution of a hair dye composition at 25° C. by 1 from the initial value thereof in accordance with the following equation:
Buffer capacity=|
dC
B
/dpH|
wherein C
B
is an ion concentration of the base (gram equivalent/L).
If the buffer capacity is lower than 0.007 gram equivalent/L, no sufficient effect can be achieved from the viewpoint of hair-dyeing effect. If the buffer capacity exceeds 0.5 gram equivalent/L, no sufficient effect can be brought about from the viewpoint of coloring to the skin. It is hence not preferable for the hair dye composition to have a buffer capacity outside the above range.
Such a buffer capacity can be imparted by adding a pH buffering agent or the like to a hair dye composition. As the pH buffering agent, may be used an organic or inorganic acid and a salt thereof which exhibit a buffering action in a pH range of 2.0-6.0. As examples of the organic acid, may be mentioned citric acid, glycolic acid, succinic acid, tartaric acid, lactic acid, fumaric acid, malic acid, levulinic acid, butyric acid, valeric acid, oxalic acid, maleic acid and mandelic acid. As examples of the inorganic acid, may be mentioned phosphoric acid, sulfuric acid and nitric acid. As examples of the salt thereof, may be mentioned sodium salts, potassium salts, ammonium salts and alkanolamine salts such as triethanolamine salts. The amount of the compounds incorporated for imparting such a buffer capacity is not particularly specified and varies according to the kinds of the compounds for imparting the buffer capacity. For example, when sodium citrate is used as a compound for mainly imparting the buffer capacity, the compound is incorporated at a concentration of at least about 1%.
In the hair dye compositions according to the present invention, the incorporation of the component (B) can enhance the penetrating rate and penetration of the acid dye into hair to a degree equal to or higher than benzyl alcohol or the like which has heretofore been in common use as a penetration accelerator. In addition, although a hair dye composition making use of benzyl alcohol or the like colors the skin to such a strong extent that it cannot be removed with ease by usual washing when it comes into contact with the skin, the hair dye compositions according to the present invention, in which the component (B) is incorporated, and the buffer capacity is adjusted to the above range, feature that they scarcely color the healthy skin even when they are brought into contact with the skin though they exhibit high hair-dyeing ability. Even if the skin is colored due to reduction in the barrier capability of the skin by skin roughness or the like, or differences between individuals, the colored part can be easily cleaned by washing with soap, shampoo or the like, or so.
At this time, it is preferred to use, as a measure of the coloring of the skin, R=&Dgr;E (pigskin)/&Dgr;E (goat hair) which is defined as a ratio of the pigskin-coloring ability &Dgr;E (pigskin) to the goat hair-dy
Miyabe Hajime
Nagashima Nozomi
Nakashimada Atsushi
Sakai Masahiko
Shibata Yutaka
Kao Corporation
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Page Thurman K.
Seidleck Brian K.
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