WASHING AND CLEANSING COMPOSITIONS CONTAINING ALKYL ETHER SULPHATES

Abstract: Alkylethersulphate-containing detergent compound, charac­ terized in that the compound contains 5-20 %(wt), calculated on the compound, of one or more alkylamidopolyglycolether carboxylic acids and/or salts thereof with the formula R-CO-NH-(C₂H₄O) n -CH₂COOM, in which R is an alkyl group with 5-21 carbon atoms and M a hydrogen atom, an alkali metal atom, an alkaline earth metal equivalent, or an ammonium or amine group and n a number with a value ranging from 2 to 10.

Description: The invention concerns alkylethersulphate-containing detergent compounds, washing and cleansing agents containing such com­ pounds and the application of the compounds and/or washing and cleansing agents. Alkylethersulphates have been known for a long time as anionic tensides applied in washing and cleansing agents. They are prepared by first ethoxylating fatty alcohols and then sulphating the obtained ether adducts. In the ethersulphates an -SO₃H-group is linked to the O-atoms of the terminal OH-group of the adduct. They are therefore sulphuric acid esters of the adducts. With respect to the corresponding non-sulphated products, they are better tolerated by the skin, but in many cases this tolerance is only limited, which, particularly in the case of washing and/or cleansing preparations coming into close and relatively prolonged contact with the skin, such as shampoos, shower and bath preparations, liquid soap, in particular for washing the hands, and dish-washing preparations for manual dish-washing, is a disadvantage. It is desirable to further improve such preparations in particular, in such a manner that they are better tolerated by the skin. An important aspect with regard to the skin's tolerance is the toxicity of detergent substances or decom­ postion products thereof with respect to the skin's bacterial flora. Detergent alkylamidopolyglycolethercarboxylic acids and salts thereof with favourable toxicity properties are known from the Euro­ pean patent application EP-A-102118. The so-called secondary toxicity of those compounds is particularly favourable. An objection to their application, however, is the high cost price. It is now been discovered that alkylethersulphate-containing detergent compounds containing 5-20 wt.%, calculated with respect to the entire compound, of one or more alkylamidopolyglycolethercar­ boxylic acids or salts thereof with the formula R-CO-NH-(C₂H₄O) n -CH₂COOM, in which R represents an alkyl group with 5-21 carbon atoms and M a hydrogen atom, an alkali metal, an alkaline earth metal equivalent or an ammonium or amine group and n a number with a value ranging from 2 to 10, have extremely favourable toxicity properties and are well tolerated by the skin at the mentioned low concentrations of the last-mentioned, i.e. most expensive, component. Alkylethersulphates always consist of mixtures of compounds with dif­ ferent degrees of ethoxylation, i.e. they contain varying numbers of glycol groups, often even including a non-ethoxylated fraction. Within the framework of the description of the invention under consideration, 'an alkylethersulphate' is also understood to mean a mixture of compounds with different alkyl groups. In general, the fatty alcohols used to prepare the alkylethersulphates are mix­ tures. Even if a fatty alcohol with one and the same number of carbon atoms is used, this often consists of a mixture of isomers. Preferably, alkylamidopolyglycolethercarboxylic acids and/or salts thereof are used in which R in the above formula represents an alkyl group with 11-17 carbon atoms. The compounds described in ther invention under consideration are therefore quite suitable for washing and cleansing agents coming into close and relatively prolonged contact with the skin, such as shampoos, shower and bath preparations and dishwashing agents. As alkylethersulphate all compounds usual for this purpose may be applied. A trade product often applied in shampoos and the like is a laurylethersulphate, in which the lauryl radical may, to a maxi­ mum of approx. 40%, be replaced by myristyl, the number of glycol units generally being two or three in this product. It will be clear to any specialist that whenever there is mention of a certain number of glycol units in ethoxylated compounds, an average value is implied. It is common knowledge that mixtures of compounds with different num­ bers of glycol groups are obtained in ethoxylated processes. In the following examples the invention will be illustrated on the basis of the application of the above-mentioned product, solely because this is the most common trade product. Obviously the invention is not limited to this. This laurylether­ sulphate is usually applied as sodium salt, but naturally other salts, such as potassium, magnesium and amine salts, though more expensive, may also be used. The preparation of the alkylamidopolyglycolethercarboxylic acids is described in the above-mentioned European patent application EP-A-102118. The following, non-limiting experiments will illustrate the invention. The experiments were conducted according to the so-called 'patchtest method'. The aim was to determine the degree of primary irritation of the skin caused by the substances concerned in com­ parison with a control substance. The experiment was conducted with a group of 25 men and women varying in age from 16 to 65. The samples control substances were applied to the skin of the upper arm by means of a sealing 'finn chamber'. This is a sealing aluminium disc providing a test area of 50 mm² with a diameter of 8 mm and a volume of 25 µl. These are set at standard intervals of 1 cm on a non-sealing support plaster. These plasters were left in contact with the skin for 24 hours and were then removed. The skin reaction was determined one hour after the removal of the plaster. Immediately after this determination a second identical plaster with the same substance was applied to the same part of the skin and then left in contact with the skin for another 24 hours. Once more the reaction was determined one hour after the removal of the plaster. The samples were distributed arbitrarily among the different volunteers. All deter­ minations were performed under standard light conditions by a trained person who did not know which samples had been applied to which per­ sons. The degree of irritation is expressed in figures from 0 to 4. These figures have the following meaning: 0 = no visible reaction; 1 = reaction only just visible; 2 = slight reaction; 3 = moderate reaction; 4 = serious reaction. The irritation symptoms were rated as follows: A rating for each skin area was obtained by multiplying the rating for the degree of reaction by the rating for the observed symp­ toms. The obtained values were summed to produce a total rating for the degree of irritation in that area. As an example it can be mentioned that the total score for an area where R3, D2 and G1 are observed, would be: (3 × 3) + (2 × 1) + (1 × 1) = 12. The substances examined were laurylpolyethersulphate as sodium salt with 2 ethoxy groups, indicated as 'A' below, and lauryl-NH-(OCH₄) x OCH₂COONa, in which x equals 4, indicated as 'B' below. Experiments were conducted with respectively 1. 100% A 2. 95% A + 5% B 3. 88% A + 12% B 4. 100% B. All samples were examined in concentrations of 15% in water. The following table shows the average results of the ratings of the skin irritation after 24 and 48 hours for each of these experi­ ments. It is apparent from the table that by using relatively large amounts of relatively cheap alkylethersulphates for detergent com­ pounds as described in the invention, a product that is tolerated very well (better than expected) by the skin is nevertheless obtained. The invention also concerns the application of the compounds under consideration and the preparations containing the compounds under consideration in commerce and industry, e.g. in hairdressing salons, the catering industry and the like.

Claims: 1. Alkylethersulphate-containing detergent compound, characterized in that the compound contains 5-20 wt.%, calculated with respect to the compound, of one or more alkylamidopolyglycolether carboxylic acids and/or salts thereof with the formula R-CO-NH-(C₂H₄O)n-CH₂COOM, in which R represents an alkyl group with 5-21 carbon atoms and M a hydrogen atom, an alkali metal atom, an alkaline earth metal equivalent, an ammonium or amine group and n a number with a value ranging from 2 to 10. 2. Compound as described in claim 1, characterized in that it con­ tains an alkylamidopolyglycolether carboxylic acid and/or salt thereof with the above formula, in which R represents an alkyl group with 11-17 carbon atoms. 3. Compound as described in claim 1 or 2, characterized in that it contains sodiumlaurylethersulphate with 2 glycol groups as alky­ lethersulphate. 4. Washing and/or cleansing agent containing a compound as described in one or more of claims 1-3. 5. Application of a compound as described in one or more of claims 1-3 and/or of a washing and/or cleansing agent as described in claim 4 in commerce and industry. 6. Alkylethersulphate-containing detergent compound or a washing and/or cleansing agent containing such compound, essentially as described in the description and the examples. Claims for Contracting State AT 1. Method for the preparation of an alkylethersulphate-containing detergent compound, characterized in that 5-20 % (wt), calculated with respect to the total weight, of one or more alkylamidopo­ lyglycolether carboxylic acids and/or salts thereof with the for­ mula R-CO-NH-(C₂H₄O)n-CH₂COOM, in which R is an alkyl group with 5-21 carbon atoms and M a hydrogen atom, an alkali metal atom, an alkaline earth metal equivalent or an ammonium or amine group and n a number with a value ranging from 2 to 10, is added. 2. Method according to claim 1, characterized in that an alkylamido­ polyglycolether carboxylic acid and/or salt thereof with the above formula, in which R is an alkyl group with 11-17 carbon atoms, is used. 3. Method according to claim 1 or 2, characterized in that the alky­ lethersulphate used is sodiumlaurylethersulphate with 2 glycol groups.

Inventors: MEIJER, HAMKE, SMID, JACOB KORNELIS
Applicants: STAMICARBON B.V.
Application year: 1986
Main classification: C11D1
IPC codes: C11D1