Drug – bio-affecting and body treating compositions – Live hair or scalp treating compositions – Uv protectant
Reexamination Certificate
2001-11-26
2003-11-18
Lovering, Richard D. (Department: 1712)
Drug, bio-affecting and body treating compositions
Live hair or scalp treating compositions
Uv protectant
C044S364000, C106S014440, C516S033000, C524S403000
Reexamination Certificate
active
06649156
ABSTRACT:
The present application is filed under 35 U.S.C §371 and is based on International Application PCT/FR00/00330 with an international filing date of Feb. 10, 2000, and which was published as WO 00/49098 on Aug. 24, 2000.
The present invention relates to an organic sol and to a solid compound based on cerium oxide and on an amphiphilic compound, and to processes for their preparation.
Sols or colloidal dispersions of cerium oxide in organic media are known. However, the processes for preparing these sols do not allow a large variety to be obtained. The sols prepared by these processes are essentially sols in a nonpolar organic medium. The processes of the prior arc generally proceed via the preparation of an aqueous sol in a first stage, and, in a second stage, placing this aqueous sol in contact with an organic phase in order to carry out the transfer of the cerium oxide into the organic phase. Such an approach is not suitable for preparing sols in water-miscible polar phases. Now, cerium oxide sols can be used in a multitude of applications, such as catalysis, anticorrosion coatings and paints. This variety of applications thus gives rise to a need for sols with varied characteristics and of different types from those already known, and also a need for processes suitable for their preparation.
One object of the invention is to provide such organic sols.
Another subject of the invention is a process for gaining access to a large range of organic sols and in particular to sols in polar solvents.
With this aim, the organic sol of the invention is characterized in that it comprises cerium oxide particles; an organic liquid phase and at least one amphiphilic compound chosen from polyoxyethylenated alkyl ethers of carboxylic acids, polyoxyethylenated alkyl ether phosphates, dialkyl sulphosuccinates and quaternary ammonium compounds.
The invention also relates to a process for preparing such a sol, which, according to a first variant, is characterized in that the abovementioned amphiphilic compound and the organic liquid phase are mixed together and the cerium oxide particles are then dispersed in the mixture obtained. According to a second variant, the process is characterized in that a mixture of cerium oxide and of at least one abovementioned amphiphilic compound is formed and the said mixture is them dispersed in the organic liquid phase.
The sols of the invention have the advantage of being able to exist in a wide range of solvents: polar or non-polar solvents.
Other characteristics, details and advantages of the invention will emerge even more fully on reading the description which follows, as well as the various concrete, but in no way limiting, examples intended to illustrate it.
For the remainder of the description, the expression “sol or colloidal dispersion of cerium oxide” denotes any system consisting of fine solid particles of colloidal size based on cerium oxide and/or hydrated cerium oxide (hydroxide) suspended in a liquid phase, it moreover being possible for the said species optionally to contain residual amounts of bound or adsorbed ions such as, for example, nitrates, acetates, citrates or ammoniums. It will be noted that, in such dispersions, the cerium can be either totally in the form of colloids, or simultaneously in the form of ions and in the form or colloids.
The cerium oxide particles generally have a mean diameter of not more than 100 nm, more particularly of not more than 50 nm and even more particularly of not more than 20 nm. For example, this diameter can be between 5 and 10 nm. It is specified here that the expression “mean diameter of the particles or colloids” should be understood as denoting the mean hydrodynamic diameter of these particles or colloids, and as determined by quasi-elastic light scattering according to the method described by Michael L. McConnell in the review Analytical Chemistry 53, No. 8, 1007 A, (1981).
Finally, the cerium is generally present in the form of cerium IV. The cerium can also be present in the form of a mixture of cerium III and cerium IV in any respective proportions.
The organic liquid phase in the sol of the invention can be based on an organic liquid or a mixture of organic liquids of very varied nature.
The organic liquid or solvent can be an inert aliphatic or cycloaliphatic hydrocarbon, or a mixture thereof, such as, for example, mineral or petroleum spirits which can also contain aromatic components. Mention may be made, as a guide, of hexane, heptane, octane, nonane, decane, cyclohexane, cyclopentane, cycloheptane and liquid naphthenes. Aromatic solvents such as benzene, toluene, ethylbenzene and xylenes are also suitable, as are petroleum fractions of the Isopar or Solvesso type (registered trade marks of the company Exxon), in particular Solvesso 100 which essentially contains a mixture of methylethylbenzene and trimethylbenzene, and Solvesso 150 which comprises a mixture of alkylbenzenes, in particular of dimethylethylbenzene and tetramethylbenzene.
It is also possible to use chlorinated hydrocarbons such as chlorobenzene, dichlorobenzene or chlorotoluene, as well as aliphatic and cycloaliphatic ethers such as diisopropylether and dibutylether, and aliphatic and cycloaliphatic ketones such as methyl isobutyl ketone, diisobutyl ketone and mesityl oxide.
It is also possible to use ketones, such as acetone, aldehydes, nitrogenous solvents such as acetonitrile, alcohols, acids and phenols.
Esters can also be envisaged. As esters which can be used, mention may be made in particular of those derived from the reaction of acids with C1 to C8 alcohols and in particular palmitates of secondary alcohols such as isopropanol. The acids from which these esters are derived can be aliphatic carboxylic acids, aliphatic sulphonic acids, aliphatic phosphonic acids, alkylarylsulphonic acids and alkylarylphosphonic acids containing from about 10 to about 40 carbon atoms, and being either natural or synthetic. Examples which may be mentioned are fatty acids of tall oil, of coconut oil, of soybean oil, of tallow oil or of flax oil, oleic acid, linoleic acid, stearic acid and its isomers, pelargonic acid, capric acid, lauric acid, myristic acid, dodecylbenzenesulphonic acid, 2-ethylhexanoic acid, naphthenic acid, hexoic acid, toluenesulphonic acid, toluenephosphonic acid, laurylsulphonlc acid, laurylphosphonic acid, palmitalsulphonic acid and palmitalphosphonic acid.
According to one particularly advantageous characteristic of the sol of the invention, the organic liquid phase is based on a polar solvent or on a mixture of polar solvents. The expression “polar solvent” means solvents which have a dielectric constant ∈ of greater than 5, as defined in particular in the book “Solvents and Solvent Effects in Organic Chemistry”, C. Reichardt, VCH, 1988. This polar solvent can be chosen from halogenated solvents such as dichloromethane; esters such as ethyl acetate, isopropyl palmitate or methoxypropyl acetate; alcohols such as ethanol, butanol or isopropanol; polyols such as propanediol, butanediol or diethylene glycol; ketones such as cyclohexanone or 1-methyl-2-pyrrolidinone.
According to an important characteristic of the invention, the sol also comprises an amphiphilic compound. Without wishing to be bound by an explanation, it may be considered that this amphiphilic compound is adsorbed onto or is in electrostatic interaction with cerium oxide particles or else is complexed therewith.
This compound can be chosen firstly from polyoxyethylenated alkyl ethers of carboxylic acids.
This refers to the products of formula: R
1
—(OC
2
H
4
)
n
—O—R
2
in which R
1
is a linear or branched alkyl radical which comprises in particular 4 to 20 carbon atoms, n is an integer which can range, for example, up to 12, and R
2
is a carboxylic acid residue such as, for example, —CH
2
COOH. Needless to say, it is possible to use these products as a mixture. Examples of amphiphilic compounds of this type which may be mentioned are those sold under the brand name AKYPO® by Kao Chemicals.
The amphiphilic compound can also be chosen from polyoxye
Burns Doane Swecker & Mathis L.L.P.
Lovering Richard D.
Rhodia Chimie
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