WO1997023192A1

WO1997023192A1 - Sugar surfactant-containing o/w micro-emulsions and process for preparing the same

Info

Publication number: WO1997023192A1
Application number: PCT/EP1996/005552
Authority: WO
Inventors: Thomas Förster; Marcus Claas; Bettina Jackwerth; Barbara Heide; Marianne Waldmann-Laue; Gert-Lothar Striepling
Original assignee: Henkel Kommanditgesellschaft Auf Aktien
Priority date: 1995-12-21
Filing date: 1996-12-12
Publication date: 1997-07-03
Also published as: DE19547986C1

Abstract

O/W micro-emulsions contain: (A) an oil phase based on (A1) mono- and/or diesters and/or (A2) fatty acid triglycerides; (B) as emulsifiers (B1) fatty acid N-alkylpolyhydroxyalkylamides and/or (B2) alkyl and/or alkenyl oligoglycosides, as well as (C) partial esters of fatty acids with polyols as co-emulsifiers. These O/W micro-emulsions may be prepared in a two-stage cold preparation process and are characterised by their storage stability, their good environmental compatibility and excellent nourishing properties.

Description

O / W MICROEMULSIONS CONTAINING SUGAR TENSIDE AND METHOD FOR THE PRODUCTION THEREOF

introduction

The invention relates to O / W microemulsions containing sugar surfactant and to a process for their preparation.

State of the art

Microemulsions are optically isotropic, thermodynamically stable systems that contain a water-insoluble oil component, emulsifiers and water. The clear or transparent appearance of the microemulsions is a consequence of the small particle size of the dispersed emulsion droplets, which are essentially below 300 nm, fine particles in the range between 100 and 300 nm, brown-red in transparency and bluish shimmering in incident light and less than 100 nm in range optically clear microemulsions occur. The droplet size of macroemulsions is essentially over 300 nm.

Microemulsions are frequently described in the literature, but their targeted production is associated with great difficulties, since the areas of existence of the microemulsion consist of oil components, water and Emulsifiers formed three-phase diagram are usually very small and the location of these areas of existence is greatly influenced by structural features of all components and all other ingredients of such systems.

Because of their greater stability than macroemulsions, finer distribution of the inner phase, mostly higher effectiveness and better transdermal penetration of the active ingredients incorporated therein, microemulsions are of considerable importance in the formulation of cosmetic and pharmaceutical preparations. There is therefore a need for reliable methods of producing microemulsions.

DE-A-40 33 928 describes oil-in-water emulsions of water-insoluble oil components which contain an alkyl glucoside as an emulsifier.

From Langmuir 9_ (1993), No. 11, pages 2921-2925, the area of existence for a microemulsion of cyclohexane using alkyl glucoside as an emulsifier component and at very low emulsifier concentrations is known.

The complex object of the present invention was to produce microemulsions with high proportions of polar oil components.

Description of the invention

The invention accordingly relates to O / W microemulsions comprising:

A) an oil phase based on

AI) 30 to 100% by weight of the mono- and / or diesters of the formulas (I), (II) and / or (III) (I) R'-COOR ² (II) R ² -OOC-R ³ -COOR ²

(III) R'-COO-R ³ -OOC-R '. wherein R ¹ and R are alkyl groups with 1 - 22 C atoms or alkenyl groups with 8 - 22 C atoms and R ³ for alkylene groups with 2 - 16 C atoms, and which contain a total of at least 10 C atoms, and / or A2) Fatty acid triglycerides of fatty acids with 8-22 carbon atoms.

B) as emulsifiers

B 1) fatty acid N-alkyl polyhydroxyalkylamides and / or

B2) alkyl and / or alkenyl oligoglycosides each having 8 to 22 carbon atoms in the hydrophobic fat residue and

C) as co-emulsifiers, partial esters of fatty acids with 10 to 18 carbon atoms and polyols with 2 to 6 carbon atoms and 2 to 6 hydroxyl groups.

It has now surprisingly been found that using sugar surfactants as emulsifiers, microemulsions with a high polar oil content can be produced in the oil phase, only small amounts of co-emulsifier being used. The invention includes the knowledge that the microemulsions have good refatting properties.

Oil body

The oil body of the microemulsions according to the invention consists of 30 to 100, preferably 50 to 95% by weight of mono- and / or diesters of the formulas

(I) R'-COOR ² (II) R ² -OOC-R ³ -COOR ²

(III) R'-COO-R ³ -OOC-R ',

wherein R ¹ and R ^{2 are} alkyl groups with 1 to 22 carbon atoms or alkenyl groups with 8 to 22 carbon atoms and R ^{3 are} alkylene groups with 2 to 16 carbon atoms and which contain a total of at least 10 carbon atoms, and / or fatty acid triglycerides of fatty acids with 8-22 carbon atoms.

Oil components of the type of the mono- and diesters of the formulas (I), (II) and (III) are known as cosmetic and pharmaceutical oil components and as lubricants and lubricants. Among the monoesters and diesters of this type, the most important in the context of the present invention are the branched and / or unsaturated products which are liquid at room temperature (20 to 25 ° C.). Suitable as oil components monoesters (I) z. B. the methyl esters and isopropyl esters of fatty acids with 12 - 22 carbon atoms. such as B. methyl laurate, methyl stearate, methyl oleate, methyl erucate, isopropyl palmitate, isopropyl myristate, isopropyl palmitate, isopropyl stearate, isopropyl oleate. Other suitable monoesters are e.g. B. n-butyl stearate, n-hexyl laurate. n-isononanoate, 2-ethylhexyl palmitate, 2-ethylhexyl laurate, 2-hexyldecyl stearate. 2-octyldodecyl palmitate, oleyl oleate. Oleylerucate, erucyl oleate and esters, which are obtainable from technical aliphatic alcohol mixtures and technical aliphatic carboxylic acids.

In particular, the esters of saturated and unsaturated fatty acids with 12-22 C atoms and polyols of the neopentyl type, such as neopentyl glycol, trimethylolpropane, trimethylolethane, pentaerythritol, ditrimethylpropane, dipentaerythritol and tripentaerythritol, can also be used.

Suitable dicarboxylic acid esters (II) are e.g. B. Di-n-butyl adipate. Di-n-butyl sebacate, di- (2-ethylhexyl) adipate, di- (2-hexyldecyl) succinate and di-isotridecylacelate. Suitable diol esters (III) are e.g. B. ethylene glycol dioleate. Ethylene glycol isotridecanoate, propylene glycol di (2-ethylhexanoate), butanediol diisostearate and neopentyl glycol dicaprylate.

For the purposes of the present invention, branched and / or unsaturated fatty acid monoesters are particularly preferably used, e.g. Isopropyl isostearate or decyl oleate.

As another, non-water-miscible organic compound, all, per se, liquid, water-insoluble, linear, preferably branched and / or unsaturated hydrocarbons, ethers or esters as well as fatty oils (triglycerides) and / or fatty alcohols, in particular Guerbet alcohols such as at room temperature (20 to 25 ° C) e.g. 2-octyldodecanol. be used. However, solid or higher-melting paraffins can also be used. Esters, waxes or fats are used in such quantities that the mixture with the liquid oil components remains liquid at 20 ° C.

Mineral oils and synthetically produced hydrocarbons, e.g. B. liquid polyolefins or hydrocarbons, such as. B. alkylcyclohexanes such. B. 1,3-Diisooctylcyclohexane.

Emulsifiers

Sugar surfactants can be used as emulsifiers for the purposes of the present invention. According to the invention, sugar surfactants are to be understood as the following compounds:

Alkvl and / or alkenyl oligoglycosides

Alkyl and alkenyl oligoglycosides are known nonionic surfactants which follow the formula (IV) R ⁴ 0- [G] _p (IV)

in the R for an alkyl and / or alkenyl radical having 8 to 22 carbon atoms. G stands for a sugar residue with 5 or 6 carbon atoms and p stands for numbers from 1 to 10. They can be obtained using the relevant methods of preparative organic chemistry. As a representative of the extensive literature, reference is made here to the documents EP-AI-0 301 298 and WO 90/03977.

The alkyl and / or alkenyl oligoglycosides can be derived from aldoses or ketoses with 5 or 6 carbon atoms, preferably glucose. The preferred alkyl unαV or alkenyl oligoglycosides are thus alkyl and / or alkenyl oligogiucosides.

The index number p in the general formula (IV) indicates the degree of oligomerization (DP degree), i.e. H. the distribution of mono- and oligoglycosides is present and stands for a number between 1 and 10. While p must always be an integer in a given compound and can in particular assume the values p = 1 to 6, the value p is for a specific alkyl oligoglycoside an analytically calculated quantity, which usually represents a fractional number. Alkyl and / or alkenyl oligoglycosides with an average degree of oligomerization p of 1.1 to 3.0 are preferably used. From an application point of view, preference is given to those alkyl and / or alkenyl oligoglycosides whose degree of oligomerization is less than 1.7 and in particular between 1.2 and 1.4.

The alkyl or alkenyl radical R ⁴ can be derived from primary alcohols having 8 to 22, in particular 8 to 18 and particularly preferably 12 to 16, carbon atoms. Typical examples are caprylic alcohol, capric alcohol, undecyl alcohol. Lauryl alcohol, myristyl alcohol, cetyl alcohol. Palmoleyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, elaidyl alcohol, petroseiinyl alcohol, arachyl alcohol, gadoleyl alcohol, behenyl alcohol, erucyl alcohol, Brassidyl alcohol, as well as their technical mixtures, such as those obtained in the hydrogenation of technical fatty acid methyl esters or in the course of the hydrogenation of aldehydes from Roelen's oxosynthesis. Alkyl oligoglucosides based on C _12/16 and C _{g / 16} fatty alcohol cuts with a DP of 1 to 3 are preferred.

Fatty acid N-alkyl polydroxyalkvlamide

Fatty acid N-alkylpolyhydroxyalkylamides are nonionic surfactants which follow the formula (V)

R *

R ³ CO-N- [Z] (V)

in which R ⁵ CO stands for an aliphatic acyl radical with 8 to 22 carbon atoms, R for hydrogen, an alkyl or hydroxyalkyl radical with 1 to 4 carbon atoms and [Z] for a linear or branched polyhydroxyalkyl radical with 3 to 12 carbon atoms and 3 to 10 hydroxyl groups .

The fatty acid N-alkyl polyhydroxyalkylamides are known substances which can usually be obtained by reductive amination of a reducing sugar with ammonia, an alkylamine or an alkanolamine and subsequent acylation with a fatty acid, a fatty acid alkyl ester or a fatty acid chloride. With regard to the processes for their preparation, reference is made to US Pat. Nos. 1,985,424, 2,016,962 and 2,703,798, as well as international patent application WO 92/06984. An overview of this topic by H. Kelkenberg can be found in Tens. Surf.Det. 25, 8 (1988). The fatty acid N-alkylpolyhydroxyalkylamides are preferably derived from reducing sugars with 5 or 6 carbon atoms, in particular from glucose. The preferred fatty acid N-alkylpolyhydroxyalkylamides are therefore fatty acid N-alkylglucamides as represented by the formula (VI):

R ^e OH OH OH

I I

R ⁵ CO-N-CH ₂ .CH-CH-CH-CH-CH ₂ OH (VI)

OH

The fatty acid N-alkylpolyhydroxyalkylamides used are preferably glucamides of the formula (VI) in which R is hydrogen or an alkyl group and R CO is an acyl radical having 8 to 22 carbon atoms, such as, for example: from caprylic acid. Capric acid, lauric acid. Myristic acid. Palmitic acid, palmoleic acid, stearic acid, isostearic acid. Oleic acid. Elaidic acid. Petroseline acid. Linoleic acid. Linolenic acid. Arachic acid. Gadoleic acid. Behenic acid or erucic acid or their technical mixtures. Fatty acid N-alkyl-glucamides of the formula (VI) are particularly preferred which are obtained by reductive amination of glucose with methylamine and subsequent acylation with lauric acid, C _12/14 coconut _fatty acid or C _12/16 and C _{g / 16} fatty acid cuts or a corresponding derivative can be obtained. The polyhydroxyalkylamides can also be derived from maltose and palatinose.

The use of the fatty acid N-alkylpolyhydroxyalkylamides is also the subject of a large number of publications. Their use as a thickener is known, for example, from European patent application EP-AI 0 285 768 (Hüls). In French patent application FR-A 1 580 491 (Henkel) are aqueous detergent mixtures based on sulfates and / or sulfonates. Nonionic surfactants and optionally soaps are described which contain fatty acid N-alkylglucamides as foam regulators. Mixtures of short- and long-chain glucamides are described in German Patent DE-Cl 44 00 632 (Henkel). The German Offenlegungsschriften DE-Al 42 36 958 and DE-Al 43 09 567 (Henkel) also report on the use of glucamides with longer alkyl residues than pseudoceramides in skin care products and on combinations of glucamides with protein hydrolyzates and cationic surfactants in hair care products.

Subject of the international patent applications WO 92/06153; 06156; 06157; 06158; 06159 and 06160 (Procter & Gamble) are mixtures of fatty acid N-alkylglucamides with anionic surfactants, surfactants with a sulfate and / or sulfonate structure, ether carboxylic acids, ether sulfates,

Methyl ester sulfonates and nonionic surfactants. The use of these substances in a wide variety of detergents, dishwashing detergents and cleaning agents is described in international patent applications WO 92/06152; 06154; 06155; 06161; 06162; 06164; 06170; 06171 and 06172 (Procter & Gamble).

Co-emulsifiers

Fatty acid polyol partial esters can be used as co-emulsifiers for the purposes of the present application. Monoesters or the technical mixtures of monoesters, diesters and free polyol obtained in the esterification of the polyols with 1 to 2 mol of fatty acid are preferably used. The fatty acid polyol partial esters are derived from fatty acids with 10 to 18 carbon atoms and polyols with 2 to 6 carbon atoms and 2 to 6 hydroxyl groups. Examples of suitable polyols are propylene glycol, glycerol, erythritol, trimethylolpropane, pentaerythritol, sorbitol, diglycerol, methyl glucoside or aldoses such as glucose or mannose. Suitable fatty acid polyol Partial esters are, for example, the technical glycerol or sorbitan monoesters of lauric acid, myristic acid, palmitic acid. Stearic acid. Oleic acid or technical coconut fatty acid C ₈ -C _u cuts. Glycerol monooleate is preferably used.

Surfactants

It is also possible to incorporate high-foaming anionic and / or amphoteric surfactants into the microemulsions according to the invention without impairing the transparency and the particle size. A total amount of up to about 0.2 part by weight, based on 1 part by weight of the oil phase, is preferred. Typical examples of anionic surfactants are alkylbenzenesulfonates. Alkanesulfonates. Olefin sulfonates, alkyl ether sulfonates, glycerol ether sulfonates. α- methyl ester sulfonates, sulfo fatty acids, alkyl sulfates, fatty alcohol ether sulfates, glycerol ether sulfates, hydroxymixed ether sulfates, monoglyceride (ether) sulfates, fatty acid amide (ether) sulfates, mono- and dialkyl sulfosuccinates, mono- and dialkyl sulfosuccinamides, carbonic acid sulfates, sulfonate fatty acids, sulfonate fatty acids, sulfonate fatty acids, sulfonate acid sulfate acids, sulfonate acid sulfate acid, sulfonate acid sulfate acid, sulfonate acid sulfate acid, sulfonate acid sulfate acid, sulfonate acid sulfate acid, sulfonate acid sulfate acid, sulfonate acid sulfate acid, sulfonate acid sulfate acid, sulfonate acid sulfate acid, sulfonate acid sulfate acid, sulfonate acid sulfate acid, sulfonate acid fatty acid, , Fatty acid sarcosinates, fatty acid taurides, acyl lactylates. Alkyl oligoglucoside sulfates, protein fatty acid condensates

(especially herbal products based on soy) and alkyl (ether) phosphates. If the anionic surfactants contain polyglycol ether chains, they can have a conventional, but preferably a narrow, homolog distribution.

Typical examples of amphoteric or zwitterionic surfactants are alkyl betaines, alkyl amido betaines, aminopropionates, aminoglycinates, imidazolinium betaines and sulfobetaines.

The surfactants mentioned are exclusively known compounds. With regard to the structure and manufacture of these substances, relevant reviews are, for example, J.Falbe (ed.), "Surfactants in Consumer Products", Springer Verlag, Berlin, 1987, pp. 54-124 or J.Falbe (ed.), "Catalysts, surfactants and mineral oil additives", Thieme Verlag, Stuttgart, 1978, pp. 123-217.

Additional ingredients

The microemulsions according to the invention can be made using water. Propylene glycol, glycerin or other usual water-soluble skin care substances can be diluted to the desired application concentration. If desired, conventional cosmetic thickeners, such as e.g. Xanthan or hydrophobically modified polyacrylate can be added. The water phase can contain a salt which is selected from the group formed by alkali, alkaline earth and / or ammonium halides, sulfates and / or hydrogen sulfates.

method

The emulsions according to the invention are usually prepared in a two-stage cold process. If necessary, for example when using glycerol monooleate as an emulsifier, the ingredients can also be emulsified at elevated temperature. First the oil body, the emulsifier and the co-emulsifier are emulsified with water. Subsequently, for example, perfume oil is added and the microemulsion can be diluted with water, propylene glycol and / or glycerol to the desired application concentration or viscosity-increasing substances can be added. The weight ratio of emulsifier to oil can be 1: 4 to 3: 1, a weight ratio in the range from 1: 3 to 1: 1 is preferred. The weight ratio of emulsifier to co-emulsifier can be 1: 2 to 8: 1, preferably the weight ratio is 1: 1 to 4: 1. The microemulsion can have a water content of 20 to 95% by weight. microemulsions with a water content of 60 to 90% by weight are preferred.

Industrial applicability

The O / W microemulsions according to the invention are preferably suitable for "2-in-1" skin and body care products such as, for example, facial cleansers, owing to the moisturizing effect.

By adding small amounts of the microemulsions according to the invention to surfactant preparations such as shampoos. Shower bath formulations, foam bath preparations or liquid soaps noticeably improve the skin feel and the anti-aging effect for hair. The antistatic effect of only 1% by weight of a microemulsified oil component in a shampoo formulation based on alkyl polyglucosides is more pronounced than that of adding 0.1% by weight of a commercially available cationic cellulose ether.

Examples

1. Preparation of the microemulsions

The O / W microemulsions according to the invention can be produced in a two-stage cold process. The amounts of sugar surfactant specified in the recipes (Tables 1 and 2) are emulsified with the corresponding amounts of ester oils and emulsifiers with stirring. When using waxy co-emulsifiers, e.g. Glycerin monooleate, a temperature increase is required to melt the glycerol monooleate (approx. 65 ° C). After cooling, the perfume oil and water are added. A water-clear microemulsion is obtained, which is e.g. suitable as a facial cleanser. The transmission of the solutions was determined photometrically at 650 nm.

2. Recipes for microemulsion facial cleanser

Table 1: Recipes for microemulsions (% by weight based on active substance)

3. Cleansing and moisturizing effect of the body and face

Table 2: Refatting properties of certain recipes

Legend;

Plantaren 1200 ^® C _12/16 fatty alcohol-l, 4-glucoside Plantaren 2000 ^® C _{8 / I6} -alkyl-l, 4-glucoside Monomuls 90-O-18 ^α glycerol monooleate Prisorine IPIS ® isopropyl isostearate

Hibitane chlorhexidine digluconate Eutanol G ® octyldodecanol

The cleaning performance was determined as follows:

A soiling paste consisting of 86 g kaolin, 8 g carbon black, 4 g Fe (black), 2 g Fe (yellow) and 300 g sebum. was applied to pig epidermis and then cleaned with a rubbing device. The evaluation was carried out using reflection measurements, which were determined in relation to the initial reflection.

Determination of regreasing:

After cleaning the pig epidermis, the skin is extracted from an extract

HPLC determines the content of fats / oils not naturally found in the skin.

Claims

claims

1. O / W microemulsions. containing:

A) an oil phase based on

AI) 30 to 100% by weight of the mono- and / or diesters of the formulas (I), (II) and / or (III)

(I) R'-COOR ²

(II) R ² -OOC-R ³ -COOR ² (III) R'-COO-R ³ -OOC-R ', where R and R are alkyl groups with 1 to 22 carbon atoms or alkenyl groups with 8 to 22 carbon atoms. Atoms and R ^{J represent} alkylene groups with 2-16 C atoms and which contain a total of at least 10 C atoms, and / or A2) fatty acid triglycerides of fatty acids with 8-22 C atoms,

B) as emulsifiers

B1) fatty acid N-alkyl polyhydroxyalkylamides and / or

B2) alkyl and / or alkenyl oligoglycosides each having 8 to 22 carbon atoms in the hydrophobic fat residue, and

2. O / W microemulsions according to claim 1, characterized in that they contain emulsifier and oil phase in a weight ratio of 1: 4 to 3: 1.

3. O / W microemulsions according to claims 1 and 2, characterized in that they contain 20 to 95 wt .-% water.

4. Oil-in-water microemulsions according to claims 1 to 3, characterized in that they contain emulsifiers and co-emulsifiers in a weight ratio of 1: 2 to 8: 1.

5. Oil-in-water microemulsions according to claims 1 to 4, characterized in that the water phase contains a salt which is selected from the group formed by alkali metal, alkaline earth metal and / or ammonium halides, sulfates and / or hydrogen sulfates.

6. Oil-in-water microemulsions according to claims 1 to 5, characterized in that they contain amphoteric and / or anionic surfactants

7. A process for the preparation of oil-in-water microemulsions according to claims 1 to 6, characterized in that the components are emulsified in a cold process to form a water-dilutable concentrate.