DE19649101A1 - Water-in-oil-in-water emulsion production, for cosmetics, pesticides etc. - Google Patents

Abstract

Production of w/o/w emulsions comprises preparing a w/o pre-emulsion (A) from 10-30 wt.% oil phase and 1-10 wt.% of an emulsifier mixture (I) with strong shear conditions, and then mixing with an aqueous emulsifier (II) under weak shear conditions to form a w/o/w emulsion. The final emulsion contains 50-90 wt.% of the pre-emulsion and 1-10 wt.% (II). (I) comprises (a) a fatty acid partial glyceride and/or a polyglycerol ester; and (b) a polyglycerol polyhydroxystearate. (II) are addition products of ethylene oxide and fatty alcohols and/or sterols and optionally a fatty alcohols.

Description

Field of the Invention

The invention relates to a method for producing multiple W / O / W emulsions, in which one next, under strong shear, a W / O pre-emulsion of water, an oil body and an emul gator I and then treated with weak shear with an aqueous emulsifier II, as well as the use of these multiple W / O / W emulsions for example for the production of kosme table and pharmaceutical products.

State of the art

Multiple emulsions are emulsions of emulsions. A distinction is made depending on the production multiple water / oil / water (W / O / W and oil / water / oil (O / W / O) emulsions. The most important applications The formation of multiple emulsions consists of active ingredients that are otherwise immiscible or can be assembled, processed in a recipe. Another advantage is that the Active substances can be released over a longer period of time. Multiple emulsions are therefore particularly suitable for the production of cosmetic and pharmaceutical products from of particular importance [Cosm.Toil. 105, 65 (1990)].

A particularly elegant method for producing multiple emulsions is described by S.Matsumoto in J.Coll.Interf.Sci. 57, 353 (1976): According to this, first at elevated temperature and a pre-emulsion is produced under high shear, which is then at ambient temperature and is introduced into the aqueous solution of a hydrophilic emulsifier with low shear. Sorbitan monoleate and polyethylene glycol derivative are used as the emulsifier pair.

It is also known from the extensive prior art that as hydrophilic emulsifiers for Production of multiple emulsions basically monoglycerides, sorbitan esters, polysorbates and high ethoxylated fatty alcohols come into consideration. Representative here is on the publications in  Pharm. Acta. Helv. 66 343 (1991), as well as by Seiller and Luca in Bull.Tech./Gattefosse Rep. 80, 27 (1987), S.T.P. Pharma 4, 679 (1988) and Int.J.Cosmet.Sci. 13, 1 (1991).

From Yakugaku Zasshi 112, 73 (1992) W / O / W emulsions are also known, the glycerol triplet acid esters as oil bodies and hydrophilic polymers, such as gelatin, as stabilizers contain. The use of albumin and polyacrylates as stabilizers for the water phase so How non-ionic surfactants for the oil phase is from J.Control.Rel. 3, 279 (1986). Such form However, stanchions have proven to be insufficient storage, particularly in the event of temperature fluctuations proven stable.

From the German patent DE-C1 43 11 445 (Henkel) is also a method for manufacturing multiple W / O / W emulsions are known, in which a W / O preparation is initially Emulsion of water, an oil body and an emulsifier I produces and then under schwa cher shear treated with an aqueous emulsifier II. As emulsifier I, either Fatty acid partial glycerides or polyglycerol esters used. The disadvantage here is that the method only provides multiple emulsions with sufficient storage stability if you like non-polar oils like for example, uses dioctyl ether.

The object of the invention was therefore the method known from DE-C1 43 11 445 Ren to produce multiple W / O / W emulsions to improve the use of oils any polarity, in particular also of strongly polar oils.

Description of the invention

The invention relates to a method for producing multiple W / O / W emulsions, in which initially a mixture of an oil body and a lipophilic emulsifier I under strong shear processed to a W / O pre-emulsion A and this then under low shear with egg nem aqueous emulsifier II, which is characterized in that

• (a) 10 to 30% by weight - based on the pre-emulsion A - oil bodies,
• (b) 1 to 10% by weight, based on the pre-emulsion A, of an emulsifier mixture consisting of (b 1) fatty acid partial glycerides and / or polyglycerol esters and (b2) polyglycerol polyhydroxy stearates,
• (c) 1 to 10 wt .-% - based on the multiple W / O / W emulsion - Emulsifiers II selected from the Group of adducts of ethylene oxide with fur alcohols and / or sterols as well optionally fatty alcohols is formed, and  
• (d) the pre-emulsion A in amounts of 50 to 90 wt .-% - based on the multiple W / O / W emul sion -

starts.

Surprisingly, it was found that by adding polyglycerol polyhydroxystearates to the known emulsifiers I get a system that is no longer sensitive to the polarity of a set oil body reacts, but rather the use of strongly polar vegetable oils enables. The resulting emulsions are long-term even under thermal stress space stable in storage.

Oil body

Guerbet alcohols based on fatty alcohols with 6 to 18, preferably 8 to 10 carbon atoms, esters of linear C₆-₁₀ fatty acids with linear C₆-C₂₀- Fatty alcohols, esters of branched C₆-C₁₃ carboxylic acids with linear C₆-C₂₀ fatty alcohols, esters of linear C₆-C₁₈ fatty acids with branched alcohols, especially 2-ethylhexanol, esters of linear and / or branched fatty acids with polyhydric alcohols (such as dimer diol or Trimer triol) and / or Guerbet alcohols, triglycerides based on C₆-C₁₀ fatty acids, vegetable oils, ver branched primary alcohols, substituted cyclohexanes, Guerbet carbonates, dialkyl ethers and / or alipha table or naphthenic hydrocarbons and silicone oils. The oil bodies can in Amounts of 10 to 30, preferably 15 to 25% by weight, based on the pre-emulsion A, are used will.

Emulsifier I

Emulsifier I is a mixture of two components. Fat comes as component Ia partial acid esters, polyglycerol esters and mixtures thereof in a weight ratio of 90:10 to 10:90, preferably 60:40 to 40:60. Typical examples are technical mono- and / or Diesters of glycerin with fatty acids having 12 to 22 carbon atoms, such as glycerin mo nolaurate, glycerol monopalmitate, glycerol monostearate, glycerol monoisostearate, glycerol monooleate and Glycerol monobehenate. Further typical examples are mono- and / or diesters of oligo- or Polyglycerol mixtures (degree of self-condensation 2 to 20, preferably 2 to 10) of the above Fatty acids with 12 to 22 carbon atoms, such as polyglycerol di isostearate or polyglycerol di oleate. It has proven to be particularly advantageous to use mixtures of glycerol and oligo- or  Polyglycerol esters, for example consisting of glycerol monooleate and triglycerol di-isostearate (Mixing ratio, for example, 80:20 parts by weight).

As component Ib come polyglycerol polyhydroxystearates, preferably polyglycerol poly-12-hy droxystearate in question, as in the German patent application DE-A1 44 20 516 (Henkel) be be written. These substances can in turn be used alone or in a mixture with sugar surfactants, preferably alkyl oligoglucosides or fatty acid N-methylglucamides.

The weight ratio of the two components Ia and Ib can be 75:25 to 25:75 and preferably 60: 40 to 40: 60. The emulsifiers I, ie the mixture of components Ia and Ib, can in amounts of 1 to 10, preferably 1 to 4% by weight, based on the pre-emulsion A, are used will.

Emulsifier II

Addition products of an average of 20 to 50, preferably 20 to 30, come as emulsifier II Mol ethylene oxide to fatty alcohols with 16 to 22, preferably 16 to 18 carbon atoms. Typical examples are adducts of an average of 25 to 30 moles of ethylene oxide with stearyl alcohol, Isostearyl alcohol, oleyl alcohol, elaidyl alcohol, petroselinyl alcohol, linolyl alcohol, linolenyl alcohol, macaw chyl alcohol, gadoleyl alcohol, behenyl alcohol and erucyl alcohol and their technical mixtures, such as they are used, for example, in the high-pressure hydrogenation of native fatty acid methyl esters or alde hyden obtained from Roelen's oxosynthesis. Addition products of an average of 25 to 30 moles of ethylene oxide to technical cetylstearyl alcohols.

Addition products of an average of 10 to 40 moles also come as further emulsifiers Ethylene oxide with sterols of plant and / or animal origin into consideration. Under the term sterols steroids with 27 to 30 carbon atoms are to be understood here, which only have a hydroxy at C-3 group, but otherwise no functional groups and often incorrectly as sterols are drawn [ROEMPP Chemie Lexikon, Vol. 5, 1992, p. 4302]. Typical examples are plant products of on average 10 to 40, preferably 15 to 20, moles of ethylene oxide to zoosterols, such as cholesterol, lanosterol, spongosterol or stellasterin or phytosterols such as Ergo sterol, stigmaster and sitosterol. Adducts with an average of 15 to 20 are particularly preferred Moles of ethylene oxide to soyasterol.

In a preferred embodiment of the invention, mixtures of addition products from an average of 10 to 50 moles of ethylene oxide to fatty alcohols with 16 to 22 carbon atoms and Sterols of plant and / or animal origin used. A typical example is a mix  an adduct of an average of 30 moles of ethylene oxide with cetylstearyl alcohol and one Addition product of an average of 16 moles of ethylene oxide with soyasterol in a weight ratio of 1: 5 to 5: 1, preferably 2: 1. The emulsifiers II can be used in amounts of 1 to 10, preferably 2.3 to 6.5 wt .-% - based on the multiple W / O / W emulsion - are used.

In a particular embodiment of the invention, the emulsifier II can contain fatty alcohols with 12 to 22, preferably 16 to 18 carbon atoms are added as co-emulsifiers, which in the emuls gatorphase form a liquid crystalline network and to further improve the stability of the resulting W / O / W emulsions. Suitable fatty alcohols are, for example, tech niche cetylstearyl alcohols. The weight ratio between emulsifier II and co-emulsifier can be 1: 1 to 1: 2, preferably 1: 1.5 to 1: 1.8.

Preparation of pre-emulsion A

To produce the pre-emulsion, the oil body is placed in a stirring device and mixed with the lipophilic emulsifier I added. The components are under high shear, i.e. H. at a scramble rer speed from 1000 to 2000, preferably 1200 to 1700 rpm homogenized. As a mixer For example, centripetal turbines or, in particular, colloid mills are suitable. As It has proven to be particularly advantageous to prepare the pre-emulsion A at elevated temperature peratur, d. H. at 50 to 90, preferably 70 to 80 ° C. The homogenization time is up usually in the range of 5 to 40, preferably 10 to 30, minutes. It is recommended for stabilization further, the pre-emulsion salt, preferably magnesium sulfate in amounts of 0.5 to 2% by weight - based on the pre-emulsion - to add.

The composition of the pre-emulsion A is therefore typically (water ad 100% by weight):

• (a1) 10 to 30 (preferably 15 to 25)% by weight oil body;
• (a2) 1 to 10 (preferably 1 to 4)% by weight of emulsifier
• (a3) 0.5 to 2 (preferably 0.5 to 1)% by weight of salt.

The water content of the pre-emulsion A is usually 58 to 88.5, preferably 70 to 83 % By weight.  

Preparation of the multiple W / O / W emulsion

To prepare the multiple W / O / W emulsion, the pre-emulsion A is in a stirring device submitted and mixed with the aqueous emulsifier II. The pre-emulsion A can be used in amounts of 50 to 90, preferably 65 to 80 wt .-% - based on the multiple W / O / W emulsion - used will. The components are under low shear, i.e. H. at a stirrer speed of 10 homogenized to 500, preferably 150 to 250 rpm. In turn come as stirring devices Centripetal turbines or colloid mills in particular. It has proven to be particularly advantageous proven to produce the pre-emulsion A at 20 to 60 and in particular 20 to 25 ° C. respectively. The homogenization time is usually in the range from 5 to 50, preferably 10 to 30 min. The multiple W / O / W emulsion is preferably produced after the hot-cold process drive, d. H. the pre-emulsion A is placed at 20 to 25 ° C and the heated to 40 to 80 ° C. Emulsifier phase II stirred in. The composition of the multiple W / O / W emulsion is thus typically (water ad 100% by weight):

• (b1) 50 to 90 (preferably 65 to 80)% by weight of pre-emulsion
• (b2) 1 to 10 (preferably 2 to 7)% by weight of emulsifier II
• (b3) 0 to 5 (preferably 1 to 4)% by weight of co-emulsifier.

The water content of the multiple W / O / W emulsion - the water content of the pre- Emulsion A included - 57 to 93, preferably 74 to 89% by weight.

Industrial applicability

The multiple W / O / W emulsions obtainable by the process according to the invention can also manufactured using highly polar oils, prove to be stable and even with long storage are easily biodegradable. They are suitable for recording and controlled time-delayed ab administration of active ingredients that cannot otherwise be assembled, such as perfume oils, Dihydroxyacetone and other substances for self-tanning, depigmenting agents or sun tanning protective factors. It is also possible to incorporate liposomes into the inner phase of the emulsions bring. Another object of the invention therefore relates to the use of the invented Multiple W / O / W emulsions obtainable according to the invention for the production of cosmetic and pharmaceutical products, in particular hair and body cleansing and care products, in which the multiple emulsions in amounts of 1 to 99, preferably 10 to 50 wt .-% - based on the means - may be included. In a particular embodiment of the invention, the multiple W / O / W emulsions for the production of pesticide formulations for agriculture. Other areas of application are emulsions for paper production and in food Industry.

Examples example 1

20 g of dioctylcyclohexane, 2 g of glyceryl oleate and 2 g of polyglycerol were placed in a centripetal turbine Poly-12-hydroxystearate (Dehymuls® PGPH, Henkel KGaA, Düsseldorf / FRG) and with a Solution of 0.7 g of magnesium sulfate in 75 ml of water. After that, the reaction mixture homogenized at 80 ° C and over a period of 10 min at a speed of 1500 rpm. The speed was then reduced to 1125 and then to 750 rpm and homogenized for a further 10 minutes each. 77 g of the pre-emulsion A prepared in this way were submitted at 23 ° C and within 40 s with a 70 ° C hot solution of 2.1 g of ceteareth-30 and 1 g of PEG soy asterol are added to 20 g of water and at a rate of 30 min over a period of 30 homogenized speed of 200 rpm. The result was a finely divided W / O / W emulsion that also after 21 days storage at 45 ° C remained stable.

Example 2

In a centripetal turbine, 20 g of dioctyl ether, 2 g of polyglycerol di-isostearate and 2 g of poly Glycerol submitted poly-12-hydroxystearate and with a solution of 0.7 g of magnesium sulfate in 75 ml Water added. The reaction mixture was then at 80 ° C and over a period of 10 min homogenized at a speed of 1500 rpm. Then the speed first reduced to 1125 and then to 750 rpm and each homogenized for a further 10 min. 77 g of Pre-emulsion A prepared in this way were initially introduced at 20 ° C. and within 40 s a 75 ° C solution of 2.1 g of ceteareth-30 and 1 g of PEG soyasterol in 20 g of water and homogenized over a period of 30 min at a speed of 200 rpm. It resulted a finely divided W / O / W emulsion that remained stable after 45 days at 45 ° C.  

Example 3

In a centripetal turbine, 20 g of almond oil, 2 g of glyceryl oleate and 2 g of polyglycerol poly-12- Hydroxystearate submitted and mixed with a solution of 0.7 g of magnesium sulfate in 75 ml of water. The reaction mixture was then at 80 ° C and over a period of 10 min at a Ge homogenized speed of 1500 rpm. Then the speed was initially up 1125 and then reduced to 750 rpm and each homogenized for a further 10 min. 77 g of this Pre-emulsion A prepared in this way was initially introduced at 25 ° C. and at 40 ° C. within 40 s hot solution of 3.1 g of PEG soyasterol in 20 g of water and added over a period of 30 min homogenized at a speed of 200 rpm. The result was a finely divided W / O / W emulsion, which remained stable after 45 days at 45 ° C.

Example 4

20 g of silicone oil, 2 g of polyglycerol di-isostearate and 2 g of polyglycerol were placed in a centripetal turbine Poly-12-hydroxystearate presented and with a solution of 0.7 g of magnesium sulfate in 75 ml of water transferred. The reaction mixture was then at 80 ° C and over a period of 10 min at a Homogenized speed of 1500 rpm. Then the speed was initially up 1125 and then reduced to 750 rpm and each homogenized for a further 10 min. 77 g of this Pre-emulsion A prepared in this way were initially introduced at 24 ° C. and at 40 ° C. within 40 s hot solution of 2.1 g of ceteareth-30 and 1 g of PEG soyasterol in 20 g of water and added over a Homogenized period of 30 min at a speed of 200 rpm. The result was one finely divided W / O / W emulsion, which remained stable even after 21 days of storage at 45 ° C.

Claims (11)

1. A process for the preparation of multiple W / O / W emulsions, in which a mixture of an oil body and a lipophilic emulsifier I is first processed under strong shear to form a W / O pre-emulsion A and this is then carried out under low shear with a further treated aqueous emulsifier II, characterized in that

• (a) 10 to 30% by weight - based on the pre-emulsion A - oil bodies,
• (b) 1 to 10% by weight, based on the pre-emulsion A, of an emulsifier mixture consisting of (b1) fatty acid partial glycerides and / or polyglycerol esters and (b2) polyglycerol polyhydroxystearates,
• (c) 1 to 10% by weight, based on the multiple w / o / w emulsion, of emulsifiers II selected from the group formed by adducts of ethylene oxide with fatty alcohols and / or sterols and, if appropriate, fatty alcohols, and
• (d) the pre-emulsion A in amounts of 50 to 90% by weight, based on the multiple W / O / W emulsion -

starts. 2. Process according to claims 1 and 2, characterized in that one as an emulsifier Mixtures of fatty acid monoglycerides and polyglycerol-poly-12-hydroxystearates are used. 3. Process according to claims 1 and 2, characterized in that the fatty acid partial glycerides and the polyol polyhydroxystearates in a weight ratio of 25:75 to 75:25 starts. 4. Process according to claims 1 to 4, characterized in that the emulsifier II Addition products of an average of 20 to 50 moles of ethylene oxide with fatty alcohols with 16 to 22 Uses carbon atoms. 5. Process according to claims 1 to 4, characterized in that the emulsifier II Addition products of an average of 10 to 40 moles of ethylene oxide with plant sterols and / or animal origin.   6. Process according to claims 1 to 5, characterized in that the emulsifier II Mixtures of addition products with an average of 10 to 50 moles of ethylene oxide Fatty alcohols with 16 to 22 carbon atoms and sterols of vegetable and / or animal origin starts. 7. The method according to claims 1 to 6, characterized in that the emulsifier II fatty alcohols with 12 to 22 carbon atoms also used. 8. Use of multiple W / O / W emulsions by the method according to claims 1 to 7 for the production of cosmetic and pharmaceutical products. 9. Use of multiple W / O / W emulsions by the method according to claims 1 to 7 for the production of pesticide-containing formulations for agriculture. 10. Use of multiple W / O / W emulsions by the method according to claims 1 to 7 for the production of tools for the paper and food industry.