Polyether Derivatives, Their Use as Emulsifiers, and Emulsions Containing the New Polyether Derivative

The present invention is directed to new polyether derivatives prepared by the gradual addition of a long-chain 1,2-epoxy with a chain length of 10 to 32 carbon atoms, at temperatures from 100.degree. to 200.degree. C., to an alcohol ethoxylate, specifically, either (1) polyethylene glycol monoalkylether, the average molecular weight of which is 400 to 2500 and the alkyl group of which contains 1 to 3 carbon atoms; or to (2) a polyethylene glycol-polypropylene glycol monoalkylether, the average molecular weight of which is 450 to 3100 and the repeating ethylene oxide and propylene oxide units of which form one block each, with the polypropylene glycol block having an average molecular weight of at most 600, whereby its alkyl group forms the end of the polyethylene glycol block and contains 1 to 3 carbon atoms, making use of 0.1 to 1% by weight of alkali hydroxide, referred to the total quantity of the initial materials. In this specification, the initial materials are the 1-2-epoxy and the alcohol ethoxylate.

These polyether derivatives correspond to the general formula: ##STR2## wherein R.sub.1 =an aliphatic hydrocarbon radical containing 1 to 3 carbon atoms;

R.sub.2 =an aliphatic hydrocarbon radical containing 8 to 30 carbon atoms;

m=10-50 (average);

n=0-10 (average);

p=1-10 (average).

In this specification, the terms "mean value" and "average" are used interchangeably. The new polyether derivatives are prepared in a manner analogous to the known reactions of alcohols with 1,2-epoxides, as described in Houben-Weyl, Methoden der organischen Chemie (Methods of Organic Chemistry), vol. 14.2, pp. 436-450 (1965).

Known emulsifiers include sorbitan, fatty acid esters and their ethoxylates, nonionogenic anion-active and cation-active detergents, partial ester salts of phosphoric acid, and the like. Ester compounds preponderate among known emulsifiers, but they have the disadvantage of being very hydrolysis-sensitive. Emulsifiers containing amine nitrogen in bound form are generally toxic and irritating to the skin. The polyether derivatives pursuant to the invention are especially well suited for emulsifiers and, in contrast to most of the known emulsifiers, can be used in oil-in-water as well as in water-in-oil emulsions. Thus, the present derivatives are excellently suited for cosmetic and industrial emulsions. Compared to esters, they are singularly resistant to hydrolyzation. Antioxidants are not required. They are dermatologically and toxicologically unobjectionable.

Preferred polyether derivatives are those in which the chain length of the long-chain epoxy is 12 to 20 carbon atoms (R.sub.2 =10-18). Also preferred are polyether derivatives in which the alkyl radical is a methyl group.

Pursuant to the invention, the new polyether derivatives are used as emulsifiers. Depending upon the structure of the molecule, the derivatives can be used as effective emulsifiers in either oil-in-water emulsions or water-in-oil emulsions. The derivatives are suitable emulsifiers for oil-in-water emulsions when the proportion of polyether blocks comprised of polyethylene oxide units and, if required, of polypropylene oxide units, is at least 60% by weight of the total polyether derivative. Excellent emulsifiers for water-in-oil emulsions are those in which the proportion of polyether blocks made up of polyethylene oxide units and, if required, of polypropylene oxide units, amount to no more than 50% of the total polyether derivative. For cosmetic applications, the water-in-oil emulsions are preferred. Specifically, the present emulsifiers have a spontaneous emulsifying effect on cosmetics, and result in creams having a smooth and bright appearance and which are not sticky and are easily distributed on the skin.

The emulsifiers pursuant to the invention are colorless, odorless, and resistant to oxidative influences. The emulsions prepared in this manner can be used without difficulty by persons with a sensitive skin, and leave a pleasant feeling thereon. Only minimal amounts of perfumes need be added, as the emulsifier has no unpleasant odor to mask. This factor is also beneficial for persons with a sensitive skin.

The emulsions pursuant to the invention are prepared in a simple manner, i.e., by dissolving the polyether derivatives used as emulsifiers in the oil phase at a temperature of about 75.degree. C., followed by the slow addition of the water phase heated to about 75.degree. C., with stirring of the resulting emulsion. It is most expedient to dissolve or distribute materials to be contained in, for example, the cosmetic emulsions, such as skin moisture regulators, plant extracts of active substances, vitamins, hormones, pigments, salts, perfume oils, UV filtering agents, or dyestuffs, in the phase which will best accept them. The required quantity of emulsifier is 0.5 to 10% by weight, referred to the total weight of the emulsion. The quantity of water to be incorporated may amount to 20 to 80% by weight, referred to the total weight of the emulsion.

Customarily utilized products, such as animal and vegetable oils and fats; synthetic esters of fatty acids with aliphatic alcohols; higher fatty alcohols; waxes; the so-called mineral fats and oils, such as paraffin oil, vaseline or ceresin; silicone oils; and silicone fats can be considered as the oil phase of the emulsion pursuant to the invention. The following examples are intended to explain the invention in greater detail .

The appropriate alcohol ethoxylate is melted in a three-necked flask having a stirrer, descending condenser, thermometer and gas supply tube, under a nitrogen atmosphere and mixed with 0.5% (wt.) of a 45% aqueous potassium hydroxide solution. The substance is heated to 60.degree. C. in 0.5 hours by passing nitrogen through it. A water-jet vacuum is then applied, and the substance is heated to 100.degree. C. over the next 0.5 hours and held at this temperature under the vacuum for 0.5 hours. The vacuum is released by adding nitrogen, and the substance heated to 180.degree. C. in 0.5 hours. The epoxyalkane is added dropwise over the next one hour. The reaction has come to an end after an additional reaction time of 2 hours, and each of the present compounds prepared in this manner is then cooled to 100.degree. C. and neutralized with 90% lactic acid.

The composition and characteristics of products prepared in this manner are compiled in Table 1. For each of these products, the following alcohol ethoxylated and epoxyalkanes were used:

The water-in-oil and oil-in-water emulsions referred to in the following examples were prepared by heating the present emulsifiers together with the other components of the fatty phase to 75.degree. C. Separately, the components of the water phase were likewise heated to 75.degree. C. and then slowly added to the hot fatty phase with initially rapid stirring. If desired, perfume may be added after the finished emulsion has cooled. The emulsions in which commercially available emulsifiers had been used for comparison purposes were prepared in a corresponding manner. The stability in storage of all the resulting emulsions was evaluated by checking them during a period of at least 3 months for oil or water separation. Their thermal stability was determined at 45.degree. C. as was their resistance to cold at temperatures of -5.degree. C.; their stability at 20.degree. C. was determined as well. The storage stability was evaluated by means of the following grades:

1=very good

2=usable

3=useless

Fatty phase

3.0 parts emulsifier

3.0 parts lanolin

5.0 parts lanolin alcohol

3.0 parts triglyceride of hydroxystearic acid

14.0 parts paraffin oil

0.2 parts preservative

Water phase

5.0 parts sorbitol 70%

0.5 parts magnesium sulfate

0.2 parts borax

65.6 parts water

0.5 parts perfume oil

The emulsions were prepared by using emulsifiers

E I=emulsifier A

E II=emulsifier D

E III=sorbitan monooleate

Fatty phase

3.0 parts emulsifier

3.0 parts PEG 20/dodecyl glycol copolymer

5.0 parts microwax

17.0 parts paraffin oil

2.0 parts lanolin alcohol

Water phase

5.0 parts sorbitol 70%

65.0 parts water

The following emulsifiers were used:

E III=emulsifier A

E IV=polyglycerin isostearate

E V=decaglycerol decaoleate

E VI=mixture of oleylphosphoric esters

Fatty phase

3.0 parts emulsifier

5.0 parts absorption base

5.0 parts beeswax

20.0 parts isopropyl stearate

Water phase

5.0 parts sorbitol 70%

62.0 parts water

The following emulsifiers were used:

E VII=emulsifier A

E VIII=polyglycerin isostearate

Fatty phase

2.0 parts emulsifier

5.0 parts isocetyl stearate

5.0 parts glycerin monostearate 90%

6.0 parts stearic acid

0.2 parts preservative

Water phase

3.0 parts glycerin

0.3 parts preservative

77.2 parts water

0.3 parts perfume oil

The following emulsifiers were used:

E IX=emulsifier B

E X=emulsifier C

E XI=polyoxyethylene glycerinmonooleate

Fatty phase

3.0 parts emulsifier

2.0 parts acetylated lanolin

1.6 parts glycerin monostearate

2.0 parts stearic acid

6.0 parts paraffin oil

2.0 parts cetyl alcohol

0.2 parts preservative

Water phase

5.0 parts sorbitol 70%

1.5 parts magnesium aluminum silicate

0.3 parts preservative

76.2 parts water

0.2 parts perfume oil

The following emulsifiers were used:

E XII=emulsifier B

E XIII=emulsifier C

E XIV=polyoxyethylene methylglucoside sesquistearate ester

Fatty phase

3.0 parts emulsifier

6.0 parts montan wax

9.0 parts isopropyl stearate

2.0 parts sesame oil

0.02 parts antioxidants

0.2 parts preservative

Water phase

0.3 parts triethanolamine

0.3 parts carboxyvinyl polymer

0.3 parts preservative

78.68 parts water

0.2 parts perfume oil

The following emulsifiers were used:

E XV=emulsifier B

E XVI=emulsifier C

E XVII=a mixture of fatty alcohol tetraglycolphosphoric esters