NO140678B - FOAMY DISHWASHER MIXTURE. - Google Patents

Description

The invention relates to foaming dishwashing detergent

mixtures.

Dishwashing detergent mixtures are put together so that they will remove food dirt and provide foam. The amount and stability of the foam is a very important factor when washing dishes,

as the user often equates the cleaning effect with pro-

ducted with the duration of the foam.

It is well known that the foam from washing-up

mixtures tend to be unstable towards food dirt,

and its collapsing may lead the user to believe that the product is not effective.

US-PS 2,987,484 describes synthetic detergents in lump form, produced by casting from a melt. A component of the soap bars is sodium dioctyl sulphosuccinate, and anionic detergents, e.g. sodium coconut alcohol sulfate, are also described as components. The patent is aimed at progress-

method for the production of lump detergents and does not describe the synergistic advantage of the active mixtures disclosed herein.

The invention provides a dishwashing detergent mixture

which is effective in terms of washing dishes by hand in removing food stains, 'and which also has a foam which is more stable than what would be expected from the separate foam ratios of the ingredients.

Consequently, the invention provides a foaming detergent mixture whose active detergent material consists of an alkyl sulfosuccinate and an alkyl sulfate, and the detergent mixture is characterized in that the sulfosuccinate is a dialkyl-(C^-Cg) ester of sulforavic acid, and that the sulfate has the formula R(OC2H4) nOS03M, wherein R is alkyl, linear or branched, of 11-18 carbon atoms; n is 0-40 when R is derived from a primary alcohol and 2-40 when R is derived from a secondary alcohol; and M is an alkali metal, ammonium or substituted ammonium ion. The weight ratio between sulfosuccinate and sulfate is 10:90 - 99:1 and is preferably approx. 1:1. The amount by weight of di-alkyl sulfosuccinate/sulphate mixture can vary from 5 to 100% and is preferably 10-60% by weight calculated on the entire mixture.

The dialkyl sulfosuccinate is preferably present in an amount of more than 5% by weight based on the entire mixture.

The dialkyl sulfosuccinate is alkali metal, ammonium

or substituted-ammonium salt and may be derived from a C^, Cg or Cg alcohol which may be linear or branched, or which

any mixture thereof. The preferred material is di-n-octyl sulfosuccinate. The di-alkyl sulphosuccinate can be prepared in a conventional way, e.g. esterification of maleic acid, followed by sulfonation with bisulfite.

The sulfates are well-known anionic synthetic detergents and they are sulfuric acid half-esters of either alkanols (ie where n = 0) or ethoxylated alkanols (ie where n = 1-40). Suitable sulfates are derived from the linear, branched, primary or secondary alcohols, with or without ethoxylation. Preferred alcohols are: 1. the linear primary alcohols having 12-14 carbon atoms, which - if ethoxylated - have up to 12 moles of ethylene oxide per

moles of alcohol;

2. the mainly straight-chain primary alcohols with 2-15 carbon atoms and approx. 25% 2-methyl branching, which - if they

is ethoxylated - has up to 12 mol of ethylene oxide per moles of alcohol; 3. the randomized secondary alcohols with 11-15 carbon atoms with 7-30 moles of ethylene oxide per; moles of alcohol.

The preferred cations are sodium and ammonium, and the latter sulfates can be an aid for hydrotroping liquid products according to the invention.

The mixtures described in this application were evaluated by measuring the foam ratio using a modified Schlachter-Dierkes test which is based on the principle described in Fette und Seifen, 1951, vol. 53, p.207. A 100 ml aqueous solution of the washing-up liquid at 0.04% detergent in 24°H water (ie 24 parts calcium carbonate per 100,000 parts water) at 45°C is stirred rapidly using a vertically oscillating, perforated disk in a measuring cylinder . After the initial formation of foam, 0.2 gram portions of dirt (9.5 parts commercial shortening, 1/4 part oleic acid, 1/4 part stearic acid, dispersed in 120 parts water and the emulsion stabilized with 10 parts wheat starch) are added with 15 second intervals (including 10 seconds of gentle stirring and 5 seconds of rest) until the foam collapses. The result is recorded as the number of oil portions (NSI assessment). Conventional detergent mixes do not give more than 35 as their NSI rating. Many of the products according to the invention will give significantly higher grades.

It has surprisingly turned out that the specified alkyl group in the sulfosuccinate is very critical to optimal foam stability. This is shown in the following table showing the foam stability of various di-alkyl sulphosuccinates in mixture (1/1 by weight) with the following sodium alkyl ether sulphates: (a) "Empimin" 3023 (lauryl alcohol sulphate ethoxylated with 10 moles of ethylene oxide per mole of alcohol, from Marchon Products Ltd.), and (b) "Tergitol" 15-S-12-S (sulfate of the randomized cn_i5~sec~ndary alcohol, ethoxylated with 12 moles of ethylene oxide per mole of alcohol, from Union Carbide & Chemical Corporation).

The above results show the surprisingly effective chain length of the di-alkylsulfosuccinate as C₁-C₂, as

n= Cg is the optimum.

It is surprising that the combination of the di-alkyl (C7-C8) sulfosuccinate and the alkyl ether sulfate is so effective, as the sulfosuccinate alone shows very poor foaming properties. Even alkyl ether-

the sulfate has surprisingly improved foaming conditions when mixed with the di-alkyl sulfosuccinate.

It will be understood that the sulfates are likely to include

some unreacted alcohol or ethoxylated alcohol, due to its incomplete conversion to the sulfate. In the examples given in this application, the percentage of unreacted alcohol in the sulfates used was of the order of 1-10% by weight of the sulfate. Tests showed that a content of unreacted alcohol of up to 20% by weight of the sulphate is not sufficient to affect the NSI grade.

The product may include other detergents, hydrotropes, solvents, opacifiers, phosphates, silicates, dyes

agents, perfume, enzymes, as well as agents that are beneficial for the skin. Selection of other detergents must necessarily ensure maintenance

sharing the foam stability property produced by the products according to the invention.

Although the invention primarily relates to liquid mixtures,

is it applicable for powder mixtures.

In the following, the invention shall be described by means of

examples of mixtures of a di-alkyl sulfosuccinate and a sulfate in water. Foam stability was determined by the NSI test described above. The NSI grades expected from knowledge of the NSI grades of the components as the only active ones are given in parentheses. The percentages of the active detergent ingredients are by weight of the total active detergent material which is consistently at a concentration of 0.04%.

The results reproduced in examples 1-4 below,

shows the synergistic effect achieved by the mixture according to the invention. The control samples are included for the sake of completeness.

Example 1.

Sodium sulfates prepared from various "Dobanol" 25 (RTM) ethoxylates, commercially available from Shell Chemical Company were used. "Dobanol"25 is mainly believed to be a pri-

more, linear alcohol (ci2-15^ me^ ca- 25% 2-methyl branching.

The results were as follows:

Example 2

Sodium sulfates of randomized secondary alcohol (C.^_.^)-ethoxylates, commercially available as "Tergitol" 15-S series from Union Carbide Chemical Corporation, were used. Those believed to contain an average of 7 and 12 moles of ethylene oxide/mol, respectively, were used. An ethoxylate with an average of 30 mol ethylene oxide/mol randomized secondary alcohol (c^i_^5^) was synthesized and sulfated. The results were as follows:

Example 3

"Empimin" 3003 (RTM) (sulfate of lauryl alcohol ethoxylated with 3 moles of EO per mole of alcohol) and "Empimin" 3023 (described earlier) were used. These ether sulfates containing an average of i

of 3 and 10 ethylene oxide units/molecule, respectively, are derived from a narrow cut coconut alcohol and are available from Marchon Products Limited.

The results were as follows:

Example 4

Sodium sulfates of "Alfol" 12-14 and "Alfol" 1214-7E0 (commercially available from Condea) were used.

The results were as follows:

Examples 5-7 show liquid detergent mixtures according to the invention.

Example 5

Example 6 Example 7

(<x>"Linevol" 79 is C7-Cg alcohol from ICI)

0.1 g in 100 ml 24°H water NSI grade =40.

The best conventional liquid dishwashing detergent mixes

gives at the same a.d. of 0.04% gives an NSI grade of 35„

Examples 8-10

shows powdery dishwashing detergent mixtures according to the invention.

Example 8

0.07 g in 100 ml 24°H water NSI grade = 48 Example 9 Example 10

The above-mentioned mixtures have satisfactory washing-up properties» Although the above properties are shown with 24°H water, equivalent or better properties are achieved in soft water (4°H).

Claims (2)

1. Foaming detergent mixture whose active detergent material consists of an alkyl sulfosuccinate and an alkyl sulfate, characterized in that the sulfosuccinate is a dialkyl {C^-Cg) ester of sulforavic acid, and that the sulfate has the formula R (OC^H^) n0S0^l!l where R is alkyl, linear or branched, of 11-18 carbon atoms, n is 0-40 when R is derived from a primary alcohol and 2-40 when R is derived from a secondary alcohol, and M is an alkali metal, ammonium or substituted ammonium, in a weight ratio between sulfosuccinate and sulfate of from 10:90 to 99:1, preferably 1:1, and preferably constitutes 10-60% by weight of the entire mixture. 2. Detergent mixture as stated in claim 1, characterized in that R is (I) a linear alkyl group of 12-14 carbon atoms, and n is 0-12; (II) a primary alkyl group with 12-15 carbon atoms with approx. 25% 2-methyl branching, and n is 0-12, or (III) a randomized secondary alkyl group of 11-15 carbon atoms, and n is 7-30.