Drug – bio-affecting and body treating compositions – Live hair or scalp treating compositions – Polymer containing
Reexamination Certificate
1999-05-27
2001-09-18
Page, Thurman K (Department: 1615)
Drug, bio-affecting and body treating compositions
Live hair or scalp treating compositions
Polymer containing
C424S070100, C424S070110, C424S070120
Reexamination Certificate
active
06290942
ABSTRACT:
This invention relates to a carboxyl-bearing silicone emulsion suitable in formulating hair preparations, a method for preparing the emulsion, and a hair preparation.
BACKGROUND OF THE INVENTION
Hair preparations comprising a conditioning component such as a cationic non-silicone polymer or cationic surfactant, in admixture with oily additives such as higher alcohols, glycerides, liquid paraffin, and esters are conventionally used for the purpose of imparting suppleness, smoothness and antistatic properties to hair. As compared with the cationic non-silicone base conditioning component used alone, blends of oily additives with the conditioning component are effective in improving suppleness and smoothness, but undesirably leave a feel of residual oil, that is, an oily or greasy sticking feel.
By contrast, silicones as typified by dimethylpolysiloxane are known to be smooth and lubricating, as compared with the above-described oily additives, and thus impart a dry feel and luster to hair. For this reason, silicones are used in many hair preparations. The silicones, however, do not have satisfactory functions of suppleness and style retention and in particular, little adsorb or remain on the hair damaged by permanent waving, coloring or bleaching, failing to exerts their full effects.
For this reason, conventional silicones must be blended in hair-care products in large amounts in order to provide satisfactory functions, with the drawback that hair base (near the scalp) and other regions where hair is less damaged feel sticky. Also blending large amounts of silicones compromises the stability of products.
Further, conventional hair-care products are not kept effective after hair washing. From this standpoint, efforts have been made to develop long-lasting hair-care products using modified silicone polymers which are more sorptive to hair. Such hair-care products are disclosed, for example, in JP-A 55-66506, 56-45406, 58-210005, 58-74602, 60-36407, 60-56916, 61-6, 61-78710, 63-275515, 63-307810, 63-307811, 1-172313, 1-190619, 1-203314, 2-273609, 2-273612, 2-502286, 3-206022, 4-36225, and 5-85918.
However, some of the hair-care products having modified silicone polymers blended therein are effective to sound hair, but fail to impart a soft and silky texture and hence, a pleasant feel to damaged hair like permanent-waved hair and split-end hair. And some other products are effective to damaged hair, but become sticky on sound hair.
Therefore, there is a demand to have a hair-care product having blended therein a silicone component capable of fully exerting its effect to both sound hair and permanent-waved or otherwise damaged hair.
SUMMARY OF THE INVENTION
An object of the invention is to provide a silicone emulsion which is formulated in a hair preparation as a silicone component, when applied to hair, remains adsorbed on hair in any state including sound hair and damaged hair, and effective for imparting smoothness, suppleness, lubricity, antistatic properties, and style-holding ability, and providing a pleasant finish and feel, while the hair preparation is shelf stable. Another object of the invention is to provide a method for preparing the silicone emulsion. A further object is to provide a hair preparation having the silicone emulsion blended therein.
In a first aspect, the invention provides a carboxyl-bearing silicone emulsion comprising an organopolysiloxane of the following general formula (1):
R
1
x
R
2
y
R
3
z
SiO
(4−x−y−z)/2
(1)
wherein R
1
is a monovalent hydrocarbon group having 1 to 20 carbon atoms, R
2
is as defined for R
1
or an OX group wherein X is hydrogen or a monovalent hydrocarbon group having 1 to 6 carbon atoms, R
3
is a —R
4
COOH group wherein R
4
is a divalent hydrocarbon group having 1 to 20 carbon atoms, x, y, and z are numbers satisfying 0<x≦2, 0≦y<0.05, 0<z≦0.15, and 1.8<x+y+z<2.2. The organopolysiloxane contains at least one carboxyl group in the molecule and has a degree of polymerization of 200 to 20,000.
In one preferred embodiment, the organopolysiloxane of formula (1) includes
(A) structural units of the following average unit formula (2):
R
1
a
R
2
b
SiO
(4−a−b)/2
(2)
wherein R
1
and R
2
are as defined above, a and b are numbers satisfying 0<a≦3, 0≦b<3, and 1≦a+b≦3,
(B) structural units of the following average unit formula (3):
R
3
c
R
2
d
SiO
(4−c−d)/2
(3)
wherein R
2
and R
3
are as defined above, c and d are numbers satisfying 0<c≦3, 0≦d<3, and 1≦c+d≦3,
(C) structural units of the following average unit formula (4):
R
1
SiO
3/2
(4)
wherein R
1
is as defined above,
in a molar ratio (A):(B):(C) of 1: (0.0001 to 0.01): (0 to 0.01).
The carboxyl-bearing silicone emulsion defined above is quite effective as a silicone component in hair preparations.
More specifically, the silicone emulsified in the above-defined emulsion has carboxyl groups serving to adsorb to hair. When the emulsion is blended as a silicone component in a hair preparation, even in an ordinary amount, the silicone imparts to less damaged hair the functions inherent to silicones and at the same time, exerts its effects to damaged hair. The silicone remains highly sorptive to hair in any state, regardless of the degree of hair damage, imparts smoothness, suppleness and antistatic effect to hair, and achieves a soft, silky, dry, non-sticking, pleasant finish. Additionally, the hair preparation is resistant to overnight kinking and tangling, and able to hold style. In summary, the hair preparation having the inventive emulsion blended therein has many benefits including high retention on hair and satisfactory effects on hair independent of the degree of damage by permanent waving or heat drying while it is free of color fading or discoloration and shelf stable.
In another aspect, the invention provides a method for preparing the above-described carboxyl-bearing silicone emulsion comprising the steps of emulsion polymerizing a mixture of organopolysiloxanes in water in the presence of an anionic surfactant for emulsion polymerization, and neutralizing the resulting reaction mixture; or the steps of emulsifying and dispersing a mixture of organopolysiloxanes in water in the presence of a nonionic or anionic surfactant, emulsion polymerizing the organopolysiloxanes in the presence of a polymerization catalyst, and neutralizing the resulting reaction mixture. The mixture of organopolysiloxanes used herein contains
(A) an organopolysiloxane of the following general formula (2a):
R
1
a
R
2
b
SiO
(4−a−b)/2
(2a)
wherein R
1
and R
2
are as defined above, a and b are numbers satisfying 0<a≦3, 0≦b<3, and 1≦a+b≦3,
(B) an organopolysiloxane of the following general formula (3a):
R
3
c
R
2
d
SiO
(4−c−d)/2
(3a)
wherein R
2
and R
3
are as defined above, c and d are numbers satisfying 0<c≦3, 0≦d<3, and 1≦c+d≦3, and optionally,
(C) an organosilane of the following general formula (4a):
R
1
Si(OX)
3
(4a)
wherein R
1
and X as defined above, or a partial hydrolytic condensate thereof.
In a further aspect, the invention provides a hair preparation comprising the carboxyl-bearing silicone emulsion.
DETAILED DESCRIPTION OF THE INVENTION
The carboxyl-bearing silicone emulsion of the invention is an emulsion in water of an organopolysiloxane of the following general formula (1):
R
1
x
R
2
y
R
3
z
SiO
(4−x−y−z)/2
(1)
wherein R
1
is a monovalent hydrocarbon group having 1 to 20 carbon atoms, R
2
is as defined for R
1
or an OX group wherein X is hydrogen or a monovalent hydrocarbon group having 1 to 6 carbon atoms, R
3
is a —R
4
COOH group wherein R
4
is a divalent hydrocarbon group having 1 to 20 carbon atoms, x, y, and z are numbers satisfying 0<x≦2, 0≦y<0.05, 0<z≦0.15, and 1.8<x+y+z<2.2, the organopolysiloxane containing at least one carboxyl group in
Aoki Hisashi
Nakazato Morizo
McQueeney P. E.
Millen White Zelano & Branigan P.C.
Page Thurman K
Shin-Etsu Chemical Co. , Ltd.
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