The present invention relates to an emulsifier composition and the use thereof in the preparation of water-in-oil emulsions.

Background

Water-in-oil emulsions, especially high inner phase content water-in-oil emulsions are well known for their special skin sensory, water resistance and skin moisturizing properties. At present, they are produced by slowly adding the inner water phase into the oil phase containing an emulsifier under stirring. However, during this process, the water phase must be added "slowly" such that all the water can be steadily encapsulated as the inner phase into the oil phase. If all the water phase and all the oil phase are directly mixed and homogenized, a water-in-oil emulsion will not be available, even the time for homogenization is extended. The above mentioned process is much different from normal processes for the preparation of oil-in- water emulsions named "one step emulsification" wherein all the water and oil phase are immediately mixed and then homogenized. As oil-in-water emulsions are easily realized, cosmetic manufactures will prefer to use oil-in-water emulsions. To some extent, the application and promotion of water-in-oil emulsions are limited by the current inconvenient process for preparing such emulsions.

Summary of the invention

The present invention provides an emulsifier composition which can improve the process for the preparation of a water-in-oil emulsion.

The present invention further provides a water-in-oil emulsion comprising the emulsifier composition of the present invention.

The present invention further provides a process for the preparation of the water-in-oil emulsion of the present invention. By the use of the emulsifier composition of the present invention, a water-in-oil emulsion can be obtained through simply mixing the inner and outer phases, which is much more convenient than conventional processes.

Detailed description of the invention

The emulsifier composition of the present invention comprises

a) at least one water-in-oil emulsifier;

b) at least one fatty acid salt of an amido amine or the precursor mixture thereof consisting of the corresponding fatty acid and the amido amine, the fatty acid having 8-22 carbon atoms,

the amido amine having the following structure, R ¹ -C(0)-NH-R ² -N(R ³ )(R ⁴ ); wherein

R ¹ is an aliphatic hydrocarbyl group having 7-21 carbon atoms;

R ² is a hydrocarbylene group having 1-4 carbon atoms;

R ³ and R ⁴ are independently a hydrocarbyl group having 1-4 carbon atoms.

Preferably, Component a) constitutes 50-99.5%, more preferably 80-99%, Component b) constitutes 0.5-50%, more preferably 1-20%,

based on the total weight of the emulsifier composition.

Preferably, Component a) is selected from surfactants having an HLB value less than 12, preferably an HLB value from 2-8, calculated according to the Davies method.

Preferably, Component a) has hydrophilic groups selected from polyoxyethylene groups, polyoxypropylene groups, polyglycerol groups, poly oxy ethylene sorbitan groups. Preferably, Component a) can be one or more selected from the following three types: The first type: an emulsifier having a molecular chain structure of polysiloxane + a hydrophilic group + an alkyl, which comprises a block copolymer emulsifier of polysiloxane, a polyetherpolyol and a C C ₂₂ aliphatic alkane connected by covalent bonds, an emulsifier with a polysiloxane chain as the main chain, and polyetherpolyol and C ₁ -C ₂₂ aliphatic alkyl as side groups which are respectively connected to the main chain of polysiloxane by covalent bonds, and an emulsifier with a polysiloxane chain as the main chain, C C ₂₂ aliphatic alkyl modified polyetherpolyol as side groups which are connected to the polysiloxane chain by covalent bonds; preferably C ₆ -C ₂ o alkyl-copolymerized polyoxyethene polydimethylsiloxane, and more preferably cetyl PEG/PPG- 10/1 polydimethylsiloxane (for example the one supplied under the trade name of ABIL ^® EM90 or ABIL ^® EM 180 by Evonik Goldschmidt GmbH);

The second type: an emulsifier having a molecular chain structure of polysiloxane + a hydrophilic group, which emulsifier comprises a block copolymer emulsifier with polysiloxane and a polyetherpolyol connected by covalent bonds, an emulsifier with a polysiloxane chain as the main chain, and polyetherpolyol as side groups connected to the main chain of polysiloxane by covalent bonds; preferably polyoxy ethylene polydimethylsiloxane, polyglycerol polydimethylsiloxane, and more preferably bis-PEG/PPG- 14/14 polydimethylsiloxane (for example the one supplied under the trade name of ABIL ^® EM97 by Evonik Goldschmidt GmbH); and

The third type: an ester emulsifier formed by a polyetherpolyol or a polyol of a non-linear structure or a linear structure, via its hydroxyl group, with a C ₁ -C ₂₂ fatty acid, or an ether emulsifier formed by a polyetherpolyol or a polyol, via its hydroxyl group, with a C C ₂ 2 fatty alcohol, which comprises a polyoxyethylene fatty acid ester, a polyoxyethylene alkyl ether, a mono- or poly- glycerol fatty acid ester, a mono- or poly- glycerol alkyl ether, preferably diisostearyl polyglyceryl- 3 dimer dilinoleate (for example the one supplied under the trade name of ISOLAN ^® GPS by Evonik Goldschmidt GmbH), polyglyceryl-4 diisostearate/polyhydroxystearate/sebacate (for example the one supplied under the trade name ISOLAN ^® GPS by Evonik Degussa GmbH), polyglyceryl-4 stearate (for example the one under the trade name ISOLAN® GI 34) and a polyoxyethylene sorbitan fatty acid ester.

The above cetyl PEG/PPG- 10/1 polydimethylsiloxane (for example the one supplied under the trade name of ABIL EM90 by Evonik

Goldschmidt GmbH) can have the following structure:

wherein R is a cetyl group, x=10, y=l, n= 1-200, o=l-100, m=l-40, the molecular weight of which is 14000g/mol.

Preferably, R ¹ is an alkyl in the structure of the amido amine of Component b).

Preferably, R ¹ is a straight or branched alkyl having 15-21 carbon atoms.

Preferably, R is an alkylene in the structure of the amido amine of Component b).

Preferably, R ³ and R ⁴ are independently an alkyl in the structure of the amido amine of Component b).

More preferably, the amido amine is

stearamidopropyldimethylamine,

stearamidopropyldiethylamine,

stearamidoethyldiethylamine,

stearamidoethyldimethylamine,

palmitamidopropyldimethylamine,

palmitamidopropyldiethylamine,

palmitamidoethyldiethylamine,

palmitamidoethyldimethylamine,

behenamidopropyldimethylamine, behenamidopropyldiethylamine,

behenamidoethyldiethylamine,

behenamidoethyldimethylamine,

arachidamidopropyldimethylamine,

arachidamidopropyldiethylamine,

arachidamidoethyldiethylamine,

arachidamidoethyldimethylamine, and

diethylaminoethylstearamide. The fatty acid of Component b) is not limited to straight or branched, saturated or unsaturated fatty acids.

More preferably, the fatty acid of Component b) is selected from lauric acid, isostearic acid, stearic acid, myristic acid, oleic acid and palmitic acid.

Preferably, the equivalent ratio of the fatty acid to the amido amine is 0.5-5: 1, more preferably 0.9-1.5: 1, particularly 1 :1. Optionally, the emulsifier of the present invention further comprises: c) at least one metal salt of a fatty acid, the fatty acid salt having 8-22 carbon atoms.

Preferably, Component a) constitutes 30-90%, more preferably 40-80%, Component b) constitutes 0.5-10%, more preferably 1-8%,

Component c) constitutes 5-65%, more preferably 20-50%,

based on the total weight of the emulsifier composition,

when the metal salt of a fatty acid presents. The fatty acid of Component c) is not limited to straight or branched, saturated or unsaturated fatty acids.

More preferably, the fatty acid of Component c) is selected from lauric acid, isostearic acid, stearic acid, myristic acid, oleic acid and palmitic acid. Preferably, the metal of Component c) is selected from Ba, Mg, Al, Zn, and Ca.

The present invention furthers provides a water-in-oil emulsion comprising:

d) an oil phase;

e) a water phase;

f) an emulsifier composition of the present invention. Preferably, the oil phase constitutes 15-65%, more preferably 20-50%, the water phase constitutes 30-80%, more preferably 50-80%,

the emulsifier composition constitutes 1-10%, more preferably 2-5%, based on the total weight of the emulsion. Preferably, the oil phase is one or more selected from siloxanes, fatty hydrocarbons, alcohols, esters and ethers.

More preferably, the oil phase is one or more selected from polydimethylsiloxanes, cyclomethicones, aryl- or alkyl- or alkoxy- substituted polydimethylsiloxanes or cyclomethicones, methyl laurate, n- hexyl laurate, 2-ethylhexyl laurate, methyl stearate, isopropyl stearate, n- butyl stearate, octyl stearate, isooctyl stearate, 2-hexyldecyl stearate, steryl heptanoate, methyl oleate, isopropyl oleate, decyl oleate, oleyl oleate, erucyl oleate, decyl linoleate, stearyl heptanoate, isopropyl myristate, myristyl myristate, isopropyl palmitate, octyl palmitate, isononyl palmitate, cetyl palmitate, 2-ethylhexyl palmitate, octyldodecyl 2-palmitate, isononyl isononanoate, cetearyl isononanoate, methyl erueate, oleyl erueate, cetyl ethylhexanoate, cetearyl ethylhexanoate, cetyl ricinoleate, and diisooctyl carbonate, di-n-butyl adipate, di-n-butyl sebacate, di(2-ethylhexyl) adipate, di(2-hexyldecyl) succinate or di-iso- tridecyl azalaate, diethylhexyl carbonate, ethylene glycol dioleate, ethylene glycol diisotridecanoate, propylene glycol di(2-ethylhexanoate), butylene glycol diisostearate, neopentyl glycol dioctoate, decyl cocoate, isocetyl palmitate, triglycerides of the mixture of octanoic acid/decanoic acid, triglycerides of industrial oleic acid, triglycerides of isostearate, triglycerides of the mixture of palmitic acid/oleic acid, caprylic/capric triglyceride, 12-15 alkyl benzoate, isostearyl benzoate, octyldodecyl benzoate, oleyl alcohol, cetyl alcohol, stearyl alcohol, octyldodecanol, polypropylene glycol- 15 stearyl ether, polypropylene glycol- 14 butyl ether, polypropylene glycol-3 myristyl ether, polypropylene glycol- 11 stearyl ether, dioctyl ether, PPG- 11 stearyl ether, PPG- 15 stearyl ether, PPG- 14 butyl ether, PPG- 3 miristyl ether, paraffin oil, white mineral oil, isohexadecane, polyisobutene, polydecene, petroleum jelly, light liquid paraffin, squalane, olive oil, sunflower seed oil, soybean oil, peanut oil, rapeseed oil, almond oil, palm oil, jojoba oil, coconut oil, liquid fraction of palm shell oil, spermaceti oil, neatsfoot oil, and liquid fraction of tallow oil.

Preferably, the water-in-oil emulsion comprises an optional water miscible alcohol, preferably the water miscible alcohol is one or more selected from monohydric alcohols, diols or triols, more preferably the water miscible alcohol is one or more selected from 1 ,2-proplyene glycol, 1,3-propylene glycol and glycerin.

Preferably, the water-in-oil emulsion further comprises at least one water soluble electrolyte, preferably the electrolyte is one or more selected from sodium chloride, potassium chloride, sodium citrate, sodium lactate, magnesium sulfate, calcium chloride and salts of amino acids.

Optionally, the water-in-oil emulsion further comprises at least one water soluble functional additive for cosmetics, for example, those supplied by Evonik Industries under the trade names TEGO ^® COSMO C 100, LACTIL ^® and TEGO ^® NATURAL BETAIN.

The present invention further provides a process for the preparation of the water-in-oil emulsion of the present invention, comprising:

1) dissolving the emulsifier composition in the oil phase;

2) mixing the water phase and the product obtained in Step 1);

3) homogenizing the mixture obtained in Step 2).

Preferably, Step 1) is carried out at 70-120°C, more preferably at 80- 110°C. Preferably, Step 2) is carried out at 70-100°C, more preferably at 80- 90°C.

Preferably, Step 3) is carried out at 70-100°C, more preferably at 80- 90°C.

Preferably, Step 3) is carried out at a stirring speed of 1000-10000 rpm, more preferably at a stirring speed of 1500-7500 rpm.

In the water-in-oil emulsion of the present invention, other components generally used in cosmetics, pharmaceuticals, and so on can be arbitrarily incorporated, as necessary, within the range that the effect of the present invention is not undermined.

Examples thereof include UV protection agents, moisturizers, water- soluble polymers, thickeners, coating agents, metal ion sequestering agents, lower alcohols, polyhydric alcohols, pH adjusters, antioxidants, antioxidant aids, and perfumes.

The use application of the water-in-oil emulsion of the present invention is not limited in particular, and the water-in-oil emulsion can be applied in cosmetic products such as pre-makeup, foundation, cheek color, eye shadow, eye liner, sunscreen products, and body-care cosmetics.

Embodiments

Chemicals

Chemicals described below with tradenames have the compositions and commercial availability indicated in Table 1.

Table 1

Formulations

The formulations of the following examples (EX 1-21) and comparative examples (CE 1, 6-10) are listed in Tables 2-20.

Table 2

Table 3

Table 6

Table 7 Table 9

Table 10

Table 11

Table 13

Table 15

Table 17

Table 19

General process for preparation

The components of Group A (mainly the oil phase and emulsifier composition) were mixed at 105°C until all the solid ingredients were dissolved completely. Then the mixture of Group A was cooled down to 80°C.

The components of Group B (mainly the water phase) were mixed at 80°C until all the solid ingredients were dissolved completely. Then both the mixtures of Groups A and B were mixed immediately at 80°C and homogenized for 2-5 minutes at a stirring speed of 1000-10000 rpm.

Optionally, the components of Group C (preservatives) were added soon afterwards.

And the obtained mixture was cooled down to room temperature under stirring.

For Examples 1-21, stable and homogenized water- in-oil emulsion systems were obtained. However, for Comparative Examples 1, 6-10, such systems were not obtained, and layer separation was observed within one minute after the homogenization stopped.