Thickened aqueous surfactant solutions

Details Thickened aqueous surfactant solutions Thickened aqueous surfactant solutions

1998-06-30

2001-10-09

Carr, Deborah D. (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Fatty compounds having an acid moiety which contains the...

C424S045000, C516S038000, C516S046000, C516S051000

Reexamination Certificate

active

06300508

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to aqueous surfactant solutions containing fatty acid ester of alkylene glycols as thickeners, to the use of fatty acid alkylene glycols as thickeners in aqueous surfactant solutions and to processes for the production of fatty acid esters of propylene glycols and for the production of fatty acid esters of ethylene propylene glycols.
BACKGROUND OF THE INVENTION
Aqueous surfactant solutions, particularly those used in the field of personal care as hair shampoos, foam baths, shower baths, hand washing pastes and the like, mostly contain anionic surfactants, for example alkyl ether sulfates. In order to stabilize these clear or disperse systems and to make them easier for the user to handle, thickeners are normally added to the surfactant solutions. Various inorganic and organic compounds used to increase the viscosity of anionic surfactant solutions are known to the expert. Water-soluble electrolyte salts, typically sodium chloride, are generally used as inorganic thickeners. Examples of organic thickeners are fatty acid alkanolamides, polyethylene glycol difatty acid esters and a number of water-soluble polymers. In most cases, the required viscosity of the surfactant solution can be adjusted with inorganic electrolyte salts alone, but only by using large quantities. Accordingly, organic thickeners are generally used in addition to the inorganic salts although, in some cases, they are attended by a number of disadvantages. Thus, surfactant solutions thickened with polyethylene glycol fatty acid diesters often show inadequate viscosity stability in storage while water-soluble polymers show unwanted slimy flow behavior with a tendency to become stringy in the thickened surfactant solutions.
Accordingly, it is proposed in German patent applications DE-A-37 30 179 and DE-A-38 17 415 to use addition products of ethylene oxide and/or propylene oxide, optionally with a narrow homolog distribution, with saturated and/or unsaturated fatty alcohols for thickening surfactant solutions. These products are not attended by the disadvantages mentioned above. However, there is a need for further organic thickeners with an increased thickening effect which make it possible in particular to use low contents of organic and inorganic thickeners for a given viscosity to be adjusted in the surfactant solution.
It has now surprisingly been found that this problem can be solved by using fatty acid esters of alkylene glycols as thickeners.
DESCRIPTION OF THE INVENTION
Accordingly, the present invention relates to thickened aqueous surfactant solutions which are characterized in that they contain as organic thickeners fatty acid esters of alkylene glycols corresponding to formula (I):
R
1
COO(AlkO)
n
H  (I)
in which R
1
CO is a linear or branched, aliphatic, saturated and/or unsaturated acyl group containing 6 to 22 carbon atoms, Alk stands for —CH
2
CH
2
—, —CH
2
CH
2
CH
2
— and/or —CH
2
CH(CH
3
)— and n is a number of 0.5 to 5.
In the context of the present invention, the expression “thickened” means that the thickened surfactant solutions have a demonstrably higher viscosity than the unthickened surfactant solutions, as determined by physicochemical methods, more particularly with a Brookfield viscometer. In addition, the terms “thickener” and “thickening agent” are used synonymously.
The fatty acid esters of alkylene glycols are products of the addition of ethylene oxide and/or propylene oxide to fatty acids with the formula R
1
COOH, where R
1
CO is as defined above. Typical examples are caproic acid, caprylic acid, 2-ethyl hexanoic acid, capric acid, lauric acid, isotridecanoic acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, isostearic acid, oleic acid, elaidic acid, petroselic acid, linoleic acid, linolenic acid, elaeostearic acid, arachic acid, gadoleic acid, behenic acid and erucic acid and the technical mixtures thereof obtained, for example, in the pressure hydrolysis of natural fats and oils, in the reduction of aldehydes from Roelen's oxosynthesis or in the dimerization of unsaturated fatty acids. Technical fatty acids containing 12 to 18 carbon atoms, for example, cocofatty acid, palm oil fatty acid, palm kernel oil fatty acid or tallow fatty acid, are preferred.
Ethoxylated, propoxylated or ethoxylated and propoxylated fatty acids with a degree of alkoxylation n of 1 to 2 are particularly preferred. The fatty acids in question may be exclusively propoxylated fatty acids, exclusively ethoxylated fatty acids or both ethoxylated and propoxylated fatty acids, the ethoxylated/propoxylated fatty acids being both random and block compounds.
The ethoxylated and/or propoxylated fatty acids, which are also known as fatty acid esters of alkylene glycols, are known compounds. They may be prepared, for example, by reaction of carboxylic acids with alkylene oxides in the presence of amines as catalysts as described in U.S. Pat. No. 3,884,946, the entire contents of which are incorporated herein by reference. Better yields can be obtained for low-ethoxylated fatty acids by the process described in copending patent application Ser. No. 08/767,123, filed Dec. 9, 1996, the entire contents of which are incorporated herein by reference. In this process, the ethoxylation is carried out in the presence of alkanolamines as catalysts and gives distinctly higher yields. In the development of the present invention, it was found that the propoxylation or propoxylation/ethoxylation of the fatty acids can also be carried out in the presence of alkanolamines. Accordingly, the present invention also relates to a process for the production of fatty acid esters of propylene glycol corresponding to formula (II):
 R
1
COO(PO)
n
H  (II)
in which R
1
CO has the same meaning as defined for formula (I), PO stands for —CH
2
CH
2
CH
2
O— and/or —CH
2
CH(CH
3
)O— and n is a number of 0.5 to 5, and fatty acid esters of ethylene propylene glycols corresponding to formula (III):
R
1
COO(EO)
x
(PO)
y
(EO)
z
H  (III)
in which R
1
CO has the same meaning as defined for formula (I), EO stands for —CH
2
CH
2
O—, PO stands for —CH
2
CH
2
CH
2
O— and/or —CH
2
CH(CH
3
)O— and x=0-5, y=0.1-5 and z=0-5, the sum of x and z being greater than 0 and the sum of x, y and z being in the range from 0.5 to 5, by propoxylation or propoxylation/ethoxylation of fatty acids, characterized in that the propoxylation or ethoxylation/propoxylation reaction is carried out in the presence of alkanolamines as catalysts.
Typical examples of alkanolamines suitable for use as basic catalysts are monoethanolamine, diethanolamine and preferably triethanolamine. The alkanolamines are normally used in quantities of 0.1 to 5% by weight and preferably in quantities of 0.5 to 3.0% by weight, based on the fatty acids.
The propoxylation and/or ethoxylation/propoxylation reaction may be carried out in known manner. The fatty acid and the catalyst are normally introduced into a stirred autoclave which is freed from traces of water before the reaction by alternate evacuation and purging with nitrogen. The fatty acid is then reacted with the propylene oxide or with the ethylene oxide/propylene oxide mixture in a molar ratio of 1:0.5 to 1:5 which may be introduced into the autoclave in portions through a siphon after heating. The fatty acids are preferably reacted with 1 to 2 moles of propylene oxide or with 1 to 2 moles of the mixture of ethylene and propylene oxide. The reaction may be carried out at temperatures of 80 to 180° C. and preferably 100 to 120° C. under autogenous pressures of 1 to 5 bar and preferably 2 to 3 bar. After the reaction, it is advisable to stir the reaction mixture for a certain time (15-90 mins.) at the reaction temperature in order to complete the reaction. The autoclave is then cooled, vented and, if desired, acids, for example, lactic acid or phosphoric acid, are added to the product to neutralize the basic catalyst.
The fatty acid esters of alkylene glycol of the type described above are normally present in the thickened

Affiliated with

Also associated with

Rating

Thickened aqueous surfactant solutions does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Thickened aqueous surfactant solutions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thickened aqueous surfactant solutions will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2594057