Betaines exhibiting improved skin-protecting characteristics and particularly reduced eye irritation are provided herein. Additionally, improved cleansing, bathing and disinfecting compositions obtained using these betaines are encompassed by the present invention.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to improved skin-protecting betaines and to improved 
cosmetic formulations, such as cleansing and bathing formulations, 
obtained therewith. 
2. Description of the Prior Art 
U.S. Pat. No. 3,225,074 shows compounds (betaines) of formula 
##STR1## 
wherein R.sub.1 represents long-chain aliphatic hydrocarbon radicals 
containing from 10-20 carbon atoms, cycloalkyl, aryl, aralkyl, or alkaryl 
radicals; M represents a bivalent radical such as --C(.dbd.A)--D--, 
--B--C(.dbd.A)-- or --B--C(.dbd.A)--D-- in which C is carbon and A, B and 
D are oxygen, sulfur and imino; R.sub.2 is an alkylene radical (--C.sub.m 
H.sub.2m --) containing from 1 to 24 carbon atoms and preferably 1-12 
carbon atoms; R.sub.3 and R.sub.4 may represent R.sub.5 --M--R.sub.2 -- 
where R.sub.5 is selected from the group consisting of R.sub.1 and 
short-chain aliphatic hydrocarbon radicals, i.e., alkyl and alkenyl, 
hydroxyalkyl 
EQU --(C.sub.2 H.sub.x R'.sub.4-x O).sub.y H 
or --R.sub.6 --COOMe where x is a whole number from 2 to 4, y is a number 
from 1 to about 100, R' is methyl, ethyl, tolyl or phenyl, and Me is 
hydrogen, ammonium or a metal, particularly an alkali metal or an alkaline 
earth metal; and R.sub.6 is an alkylene radical (--C.sub.m H.sub.2m --) 
containing from 1 to 12 carbon atoms, and preferably 1 to 6 carbon atoms. 
From German Patent No. 11 72 802 a bathing additive is known which 
comprises a surface active compound of the formula 
##STR2## 
in which R.sub.1 is an alkyl radical of a fatty acid with 10 to 18 carbon 
atoms, R.sub.2 and R.sub.3 are the same or different alkyl or 
hydroxyalkyl radicals with 1 to 4 carbon atoms, x=2 or 3 and y=1, 2, 3, or 
4. Compounds of the aforementioned type are recommended as germicidical 
shampoos. Their non-toxicity on the skin and their unusual low irritation 
of the eye are particularly recommended. It has been observed, however, 
that with commercial compounds of this type, such as where R.sub.1 is a 
radical derived from a C.sub.12-18 fatty acid, R.sub.2 and R.sub.3 are 
methyl, x=3 and y=1, eye compatibility is less than desirable. 
SUMMARY OF THE INVENTION 
It is an object of this invention, therefore, to provide betaines having 
improved skin-protecting characteristics and improved cosmetic 
compositions, such as cleansing, bathing and disinfecting compositions, 
containing these betaines. In particular, the betaines of this invention 
and their compositions exhibit less eye irritation and better 
compatibility with mucous membranes while maintaining the other desired 
properties. 
The improved betaines of this invention correspond to the general formula 
##STR3## 
wherein R.sub.1 is the acyl radical of ricinoleic acid, R.sub.2 and 
R.sub.5 are C.sub.1-4 alkylene radicals, R.sub.3 and R.sub.4 are selected 
from the group C.sub.1-4 alkyl, C.sub.1-3 hydroxyalkyl and 
hydroxypolyethoxy having from 2-20 repeating ethoxy units. Especially 
useful betaines corresponding to the above formula which exhibit 
particularly desirable properties have R.sub.2 =C.sub.3 alkylene, R.sub.5 
=methylene and R.sub.3 and R.sub.4 =methyl, ethyl, hydroxyethyl or 
hydroxypropyl. Advantageously the acyl group R.sub.1 can be derived from 
castor oil fatty acids containing greater than 80% by weight ricinoleic 
acid. A particularly useful compound of this invention is the betaine form 
of ricinoylamido-propylen-N-dimethylamino acetic acid. 
DETAILED DESCRIPTION 
In accordance with this invention improved skin protecting betaines and 
improved cosmetic compositions, such as cleansing, bathing and 
disinfecting compositions, containing these betaines are provided. Both 
the betaines and compositions formulated therewith exhibit significantly 
reduced eye irritation and better compatability with mucous membranes than 
the prior art betaines while maintaining the other desired properties. 
The present improved betaines correspond to the general formula 
##STR4## 
wherein R.sub.1 is the acyl radical of ricinoleic acid, R.sub.2 and 
R.sub.5 are alkylene radicals, i.e. bivalent hydrocarbon radicals, having 
1 to 4 carbon atoms, R.sub.3 and R.sub.4 are the same or different 
radicals selected from the group --C.sub.n H.sub.2n+1 (alkyl) where n=1 to 
4, the group --C.sub.n H.sub.2n OH (hydroxyalkyl) where n=1 to 3 or the 
group --C.sub.2 H.sub.4 O--.sub.x H (hydroxypolyethoxy) where x=2 to 20. 
Especially useful betaines of the above formula have 3 carbon atoms in the 
alkylene radical R.sub.2, R.sub.5 is a methylene (--CH.sub.2 --) group and 
the radicals R.sub.3 and R.sub.4 are methyl, ethyl or or hydroxyalkyl 
groups having 2 to 3 carbon atoms. Particularly useful is the betain of 
ricinoylamido-propylen-N-dimethylamino acetic acid. 
An essential feature of the novel betaines is that they be derived from 
ricinoleic acid, i.e. the group R.sub.1 is the acyl radical of ricinoleic 
acid. Without linking the invention to any theory it is believed that the 
surprisingly good compatability and improved performance of the present 
betaines is the result of the presence of the hydroxylated unsaturated 
fatty acyl moiety. In addition to ricinoleic acid, mixtures of fatty acids 
which are rich in ricinoleic acid can be employed, i.e. mixtures 
containing at least 50% by weight ricinoleic acid. Fatty acid mixtures 
obtained from castor oil and which contain greater than 80% by weight 
ricinoleic acid are especially useful for the preparation of the betaines 
of this invention. Betaines obtained in this manner exhibit good skin 
compatability and, in particular, show good eye compatability and 
compatability with mucous membranes. 
Improved properties are also obtained with formulations containing the 
above-defined betaines. Compositions containing at least one betaine of 
the above type and other conventional additives, such as cosmetic 
compositions including cleansing, bathing and disinfectant formulations, 
have also been found to be highly advantageous. Primarily these 
betaine-containing compositions are water-based which will additionally 
contain other common additives, such as skin-compatible surface active 
agents, thickening agents, salts, perfumes, dyes and preservatives. Due to 
their outstanding skin compatability the present betaines can be combined 
with tensides (tensio-active materials) which have poor skin compatability 
to improve the skin compatability of these latter compounds. Cleansing and 
wash compositions formulated using the betaines of this invention find 
numerous uses in cosmetic applications. 
The betaines of this invention are prepared in accordance with methods and 
procedures known to the art. Detailed explanations of the methods of 
preparation are available. In general, ricinoleic acid, or a lower alkyl 
ester (e.g. methyl) of ricinoleic acid, is reacted with a suitable amine 
and the resulting ricinoylamido compound further reacted with a compound 
such as monochloroacetic acid to produce the betaine. 
Skin compatability of the betaines is tested following the procedure 
referred to as the "Draize Eye Test" for evaluation of eye lesions 
according to J. H. Draize in "Appraisal of the Safety of Chemicals in 
Foods, Drugs and Cosmetics", Association of Food and Drug Officials of the 
United States (1959). In this test the criterion for the toxicity of a 
material for the mucous membrane of the eye is the irritation of the eye 
and its secondary organs. 
In the following evaluation employing the Draize Eye Test, data was 
obtained with the commercial betaine characterized in the introduction, 
i.e. not derived from ricinoleic acid but rather having an acyl group 
derived from a conventional (non-hydroxy substituted) C.sub.12-18 fatty 
acid, and compared with data obtained with the betaines of this invention. 
The test was carried out using six test animals with a 5% concentration of 
the active ingredient in the rabbit eye. Evaluation of eye lesions was 
made by a point system in which a higher value corresponds to a greater 
irritation of the eye and the absence of eye irritation is given a value 
of zero. 
__________________________________________________________________________ 
DRAIZE EYE TEST 
HOURS DAYS 
1 2 8 24 1 2 3 4 5 6 7 
__________________________________________________________________________ 
Commercial Betaine 
13.6 
16.8 
15.6 
20.2 
20.2 
17.6 
6 0.8 
0.8 
0 0 
Betaine of This 
Invention 9.7 
11.0 
9.7 
2.3 
2.3 
0 0 0 0 0 0 
__________________________________________________________________________ 
The above test results clearly show the substantially better eye 
compatability obtained with the betaines obtained in accordance with this 
invention. Eye irritation is much lower at the outset with the present 
betaines and additionally fades away much faster than with the commercial 
betaine of the prior art. 
The invention is further illustrated with the following examples. All parts 
and percentages are given in weight unless specifically state otherwise.

EXAMPLE I 
Preparation of betaine of ricinoylamido-propylen-N-dimethylamino acetic 
acid: Ricinoyl methyl ester (310 grams; 1 mole) was heated with 132 grams 
dimethylamino propylamine (30% molar excess) at 150.degree. C. in the 
presence of phosphoric acid catalyst. The temperature was slowly raised to 
190.degree.-195.degree. C. during which time methanol was removed from the 
reaction mixture. At the completion of the reaction, excess amine was 
removed under vacuum. 
Ricinoylamido-N-dimethylamine (381 grams; 1 mole) obtained by the above 
procedure was introduced with stirring into a solution made up of 651 
grams water, 104 grams monochloroacetic acid (1.1 mole) and 133 grams 33% 
sodium hydroxide (1.1 mole). The reaction mixture was maintained at 
60.degree.-70.degree. C. (pH 7.5-7.8) with agitation. The betaine obtained 
in this manner produced clear, colorless to slightly yellow, aqueous 
solutions. 
EXAMPLE II 
A sanitary solution was prepared by combining 15 parts (40%) 
ricinoylamido-propylen-N-dimethylamino acetic acid, sodium salt; 10 parts 
(40%) ricinoleic acid monoethanolamide sulfosuccinate, sodium salt; 5 
parts (40%) lauryl alcohol sulfate, triethanolamine salt; and water and 
with a small amount of perfume agent and preservative to bring the 
solution to 100 parts. The resulting aqueous (low viscosity) solution had 
a faint yellow color and exhibited good sanitizing properties. 
EXAMPLE III 
A mild foaming bathing formulation was prepared by combining 15 parts (40%) 
ricinoylamido-propylen-N-dimethylamino acetic acid, sodium salt; 10 parts 
(40%) lauryl alcohol triglycolether sulfosuccinate, sodium salt; 15 parts 
(40%) lauryl alcohol sulfate, triethanolamine salt; 2 parts diethanolamide 
of coconut fatty acids; 1.5 parts NH.sub.4 Cl; and sufficient water to 
bring the mixture to a total of 100 parts. The above formulation exhibited 
good foaming and cleansing properties. 
EXAMPLE IV 
Hair shampoo formulations were prepared employing the betaine of Example I 
in accordance with the following recipes: 
______________________________________ 
HAIR SHAMPOO 
Normal and 
Dry Hair 
Oily Hair 
______________________________________ 
Ricinoylamido-propylen-N-dimethyl- 
amino acetic acid, sodium salt (40%) 
15 parts 10 parts 
Laurylalcohol-triglycolether- 
sulfosuccinate, sodium salt (40%) 
10 parts -- 
Laurylalcohol sulfate, triethanol- 
amine salt (40%) 12 parts 10 parts 
Laurylalcohol-triglycolether- 
sulfate, sodium salt (28%) 
-- 20 parts 
Diethanolamide of the oleic acid 
2 parts 1.5 parts 
NH.sub.4 Cl 1-2 parts -- 
NaCl -- 1-2 parts 
______________________________________ 
Sufficient water containing a small amount of perfume, dye and 
preservative was added to each formulation to bring total to 100 parts. 
Both medium viscosity formulations had a slight yellow coloration and 
exhibited good foaming and cleansing characteristics upon application. 
EXAMPLE V 
A children's and baby shampoo was prepared by combining 15 parts (40%) 
ricinoylamido-propylen-N-dimethylamino acetic acid, sodium salt; 8 parts 
(40%) ricinoleic acid monoethanolamide sulfosuccinate, sodium salt; 15 
parts (40%) laurylalcohol sulfate, triethanolamine salt; 1-2 parts 
diethanolamide of oleic acid; 1-2 parts NH.sub.4 Cl; and sufficient water 
containing small amount of perfume, dye and preservative to bring the 
total to 100 parts. The medium viscosity shampoo had a slight yellow 
coloration.