GB2130238A

GB2130238A - Liquid detergent compositions

Info

Publication number: GB2130238A
Application number: GB08330369A
Authority: GB
Inventors: Appaya Raghunath Naik
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 1982-11-16
Filing date: 1983-11-14
Publication date: 1984-05-31
Also published as: NO834150L; ATE22574T1; DK523283A; AU2136483A; EP0112044B1; DE3366631D1; PH17916A; ZA838427B; IN158157B; DK523283D0; JPS59102994A; BR8306254A; GR81285B; GB8330369D0; EP0112044A1; CA1220695A; AU549661B2; PT77671A; GB2130238B; NZ206209A

Abstract

A high-foaming aqueous liquid detergent composition suitable inter alia for manual dishwashing contains an active detergent system including (a) a dialkyl sulphosuccinate and (b) an alkyl ether sulphate (C10-C18, 1-12 EO) containing 20% by weight or less of C14 and higher chain length material. Use of this specific type of ether sulphate enables relatively low ratios of (a) to (b), for example 2:1, to be used, thus reducing hydrotrope requirements, without sacrificing foaming performance.

Description

1 GB 2 130 238 A 1

SPECIFICATION Detergent compositions

The present invention relates to high-foaming liquid detergent compositions suitable for use in fabric washing, shampoos, and above all, in manual dishwashing operations in both hard and soft water.

The term "dishes" as used herein means any utensils involved in food preparation or consumption which may be required to be washed to free them from food particles and other food residues, greases, proteins, starches, gums, dyes, oils and burnt organic residues.

GB 1 429 637 (Unilever) discloses hand dishwashing compositions containing as detergent-active material a water-soluble salt of a di(C,--C,) alkyl ester of sulphosuccinic acid, in combination with an alkyl sulphate or an alkyl ether sulphate. Various C,-Cl, alkyl ether sulphates having different chain 10 length distributions and degrees of ethoxylation are used, as follows:

(i) Sulphated C12_C14 linear primary alcohols with degrees of ethoxylation of 1 to 12, exemplified by Empimin (Trade Mark) 3023 and Empimin (Trade Mark) 3003 ex Albright Et Wilson, which are sulphated narrow-cut coconut alcohols with average degrees of ethoxylation of 10 and 3 respectively, and by Alfol (Trade Mark) 1214-7EO ex Conoco, which is sulphated 55% C145% C,4 straight-chain alcohols with an average degree of ethoxylation of 7. (ii) Sulphated C,27-Cl, primary alcohols (about 75% linear, 25% 2-methyl-branched) having average degrees of ethoxylation of 1 to 12, exemplified by Dobanol (Trade Mark) 25-3 ex Shell, which has an average degree of ethoxylation of 3.

(iii) Sulphated random C,,-C,, secondary alcohols having average degrees of ethoxylation of 7 to 30, 20 exemplified by Tergitol (Trade Mark) 1 5-S-7 and 1 5-S-1 2 ex Union Carbide which are believed to have average degrees of ethoxylation of 7 and 12 respectively.

GB 2 108 520, GB 2 104 913, GB 2 105 325, EP 71413 and EP 71414 (Unilever) disclose high foaming combinations of certain dialkyl sulphosuccinates, particularly those having C, and C, chains, with C,,--C,, alkyl ether sulphates having degrees of ethoxylation of from 1 to 12, and in particular with Dobanol (Trade Mark) 25-3A ex Shell which, as indicated above, is a sulphated C12-Cl., primary alcohol (about 75% linear and 25% 2-methyl branched) (ammonium salt) having an average degree of ethoxylation of 3.

The present invention is based on the observation that in liquid detergent compositions based on dialkyl sulphosuccinates and alkyl ether sulphates both formulation and performance benefits may be obtained by using a particular selected group of alkyl ether sulphates. These benefits are especially apparent at relatively low ratios of sulphosuccinate to ether sulphate.

The present invention accordingly provides a foaming liquid detergent composition in the form of a clear aqueous solution containing at least 2% by weight of an active detergent mixture comprising:

(a) a water-soluble salt of a dialkyl ester of sulphosuccinic acid in which the alkyl groups may be the same or different, and (b) a C16---Cl. primary alkyl polyethoxy sulphate containing 20% by weight or less of C14 and above chain length material and having. an average degree of ethoxylation of from 1 to 12, the weight ratio of (a) to (b) being within the range of from 5:1 to 0.5 to 1, preferably 4:1 to 1:1 and especially 3:1 to 1:1.

Although in principle the concentration of the active detergent mixture in the composition may be as high as desired, provided that an aqueous solution can be obtained, it is preferably in the 2 to 60% by weight range and more preferably in the 5 to 40% by weight range.

The composition of the present invention may if desired contain other detergent-active materials 45 within its active detergent mixture, provided that the composition is substantially free of alkyl polyethoxy sulphates (ether sulphates) other than those defined under (b) above. It is, however, preferred that at least 2% by weight of the whole composition, preferably at least 5% and more preferably 10%, is constituted by dialkyl sulphosuccinate(s). Preferred additional ingredients are discussed in more detail below.

The dialkyl sulphosuccinate component (a) may if desired be constituted by a mixture of materials 50 of different chain lengths, of which the individual dialkyl sulphosuccinates themselves may be either symmetrical (both alkyl groups the same) or unsymmetrical (with two different alkyl groups).

The detergent-active dialkyl sulphosuccinates are compounds of the formula 1:

CH2-CH-SO3Xl 1 1 COOR,COOR2 (1) wherein each of R, and R2, which maybe the same or different, represents a straight-chain or branched- 55 chain alkyl group having from 3 to 12 carbon atoms, preferably from 4 to 10 carbon atoms and more preferably from 6 to 8 carbon atoms, and X, represents a solubilising cation, that is to say, any cation yielding a salt of the formula 1 sufficiently soluble to be detergent-active. The solubilising cation X, will 2 GB 2 130 238 A 2 generally be monovalent, for example, alkali metal, especially sodium; ammonium; or substituted ammonium, for example, ethanolamine. Certain divalent cations, notably magnesium, are however also suitable.

The alkyl groups R, and R2 are preferably straight-chain or (in mixtures) predominantly straightchain.

Among dialkyl sulphosuccinates that may advantageously be used in the composition of the invention are the C./C. unsymmetrical materials described and claimed in GB 2 105 325 (Unilever); the dioctyl sulphosuccinai6/dihexyl sulphosuccinate mixtures described and claimed in GB 2 104 913 (Unilever); and the mixtures of symmetrical and unsymmetrical dialkyl sulphosuccinates described and claimed in GB 2 108 520 (Unilever).

If desired the composition of the invention may additionally include one or more of the sulphonate-type detergents conventionally used as the main detergent-active agent in liquid compositions, for example, alkylbenzene sulphonates (especially C'-Cj, linear alkylbenzene sulphonates), secondary alkane sulphonates, alpha-olefin sulphonates, alkyl glyceryl ether sulphonates, and fatty acid ester sulphonates. Of course dialkyl sulphosuccinates are themselves sulphonate-type 15 detergents. If such additional sulphonate-type materials are present, the total sulphonate preferably predominates in the active detergent mixture of the composition of the invention. If no such additional sulphonate- type materials are present, the sulphosuccinate alone preferably predominates.

If desired there may also be present one or more primary or secondary alkyl sulphates. If present, these together with any sulphonate material as mentioned above, including the dialkyl sulphosuccinate, 20 preferably predominate in the active detergent mixture of the composition of the invention.

The alkyl polyethoxy sulphates or alkyl ether sulphates constituting component (b) of the composition of the invention are compounds of the general formula 11:

R3-0-(CH2CH20)n-SO3X2 (11) wherein R3 is an alkyl group having from 10 to 18 carbon atoms, X2 is a solubilising cation, and n, the 25 average degree of ethoxylation, is from 1 to 12, preferably from 1 to 8. In any given alkyl ether sulphate, a range of differently ethoxylated materials, and some unethoxylated material, will be present and the value of n represents an average. The unethoxylated material is, of course, alkyl sulphate. If desired, additional alkyl sulphate may be admixed with the alkyl ether sulphate, to give a mixture in which the ethoxylation distribution is more weighted towards lower values.

The particular ether sulphates used according to the present invention are derived from primary aliphatic alcohols and are distinguished by a content of 20% by weight or less of material having a chain length of C14 and above. The content of such long-chain material is preferably less than 10% by weight, and it is especially advantageous to use an ether sulphate substantially free of such material.

It is also preferred that the content of Cl, and shorter chain length material is as low as possible. 35 Thus the ether sulphate used according to the present invention preferably consists predominantly of C12 and C13 material.

Table 1 shows typical chain length distributions for some commercially available alkyi ether sulphates. Degrees of ethoxylation are omitted from the Table since most manufacturers provide a range of differently ethoxylated materials.

TABLE 1

Chain length distribution (weight%) Trade Name ( denotes C10 C16 Trade Mark) Manufacturer & below Cii C12 C13 C14+ cis & above Dobanol 25 Shell 25 25 25 25 Dobanol 23 Shell - 50 50 - - Empimin 3003 Albright 2-4 - 63-71 - 22-28 - 8 3002 Ef Wilson Alfol 12-14 Conoco - 55 - 45 (maximum) Preferred materials for use in the present invention are the Dobanol (Trade Mark) 23 series from Shell, which are virtually free of C14, and higher chain length material.

Materials such as Dobanol (Trade Mark) 25 ex Shell and Alfol (Trade Mark) 12-14 ex Conoco are 45 clearly outside the scope of the present invention.

1 3 GB 2 130 238 A 3 The ether sulphates used according to the present invention containing 20% or less of CW and above chain length material are preferably based on straight-chain or predominantly straight-chain alcohols. The Dobanol 23 series ex Shell, which are highly preferred for use according to the invention, consist of 75% straight-chain material and 25% 2-methyl- branched material.

Difficulties have been encountered in preparing clear, stable liquid detergent compositions based on dialkyl sulphosuccinates and alkyl ether sulphates. At relatively high ratios of sulphosuccinate to ether sulphate Q:1 and above) relatively large quantities of hydrotrope are required in order to obtain homogeneous solutions having acceptable low temperature stability, as manifested by a low cloud point, and in some cases acceptable formulations cannot be obtained even using large quantities of hydrotrope. Hydrotropes are materials present in a formulation to control solubility, viscosity, clarity and 10 stability, but which themselves make no active contribution to the performance of the product. Examples of hydrotropes include lower aliphatic alcohols, especially ethanol; urea; lower alkylbenzene sulphonates such as sodium toluene and xylene sulphonates; and combinations of these. The lower alcohols function mainly as viscosity reducers, and urea and lower alkylbenzene sulphonates mainly as solubilisers. Hydrotropes are expensive and take up room in a formulation without contributing to its 15 performance, and it is therefore desirable to use as small quantities of them as possible.

The clarity and stability of compositions based on dialkyl sulphosuccinates and conventional ether sulphates such as Dobanol 25 can be improved by lowering the ratio of sulphosuccinate to ether sulphate, but this also causes a drop in foaming performance. With the specific ether sulphates used according to the invention, however, the ratio can be lowered much further without a drop in performance, so that compositions having both acceptable physical characteristics and excellent foaming performance can be obtained.

For example, sulphosuccinate/Dobanol 25 and sulphosuccinate/Dobanol 23 mixtures have very similar foaming performances at a ratio of 4:1, but at 2:1 the performance of the former mixture has deteriorated considerably while that of the latter mixture is virtually unchanged.

The ether sulphate used in the composition of the invention has a degree of ethoxylation n of 1 to 12, preferably 1 to 8. Materials having n values of 2, 3 and 6.5 have all been found to give excellent results in compositions according to the invention. The range of 1 to 8 apparently gives optimum detergent properties in conjunction with the predominant chain lengths of C12 and C13.

As previously mentioned, additional detergent-active materials may be present in the composition, 30 provided that ether sulphates other than those specified under (b) above are absent. Thus the ether sulphates may be supplemented or partially replaced by other sulphate- type detergents, notably primary and secondary alkyl sulphates, and/or by ethoxylated nonionic detergents having from 8 to 15 carbon atoms and average degrees of ethoxylation of from 5 to 14.

Preferred nonionic detergents are short-chain high-foaming ethoxylated alcohols of the general 35 formula Ill:

F14-0-(CH2CH20)rn-H wherein R 4 is an alkyl group, preferably straight-chain, having from 8 to 12 carbon atoms, and the average degree of ethoxylation m is from 5 to 12. 40 The weight ratio of alkyl ether sulphate tononionic detergent is preferably at least 1 A and more 40 preferably within the range of from 1. 5:1 to 3:1, especially about 2:1. An especially preferred nonionic detergent is Dobanol (Trade Mark) 91-8 ex Shell, in which F14'S C9-Cl l (predominantly straight-chain) and m is 8. The stable liquid detergent compositions of the invention, preferably containing 2 to 60% by weight of active detergent, may be used for all normal detergent purposes where foaming is advantageous, for example, fabric washing products, general purpose domestic and industrial cleaning compositions, carpet shampoos, car wash products, personal washing products, shampoos, foam bath products, and, above all, manual dishwashing.

As well as active detergent, water and (if necessary) hydrotrope, the compositions may contain the usual minor ingredients such as perfume, colour, preservatives and germicides.

The invention is further illustrated by the following non-limiting Examples.

EXAMPLES

In the Examples the foaming performances of various formulations were compared using a plate washing test. In the test, plates soiled with a standard starch/fat/fatty acid mixture were washed in a standard manner with 5 litres of test solution (total concentration of the product 1.0 g/litre or 1.5 g/litre 55 in 50H or 241H (French hardness) water at 451C) in a bowl, until only a third of the surface of the solution in the bowl was covered with foam. The number of plates washed before this arbitrary end point was reached was taken as an indicator of dishwashing and foaming performance.

EXAMPLES 1-3

The performances of mixtures of dialkyl sulphosuccinate with two different ether sulphates (one 60 according to the invention, the other not) at various ratios were compared at a dosage of 1.0 g/litre in 4 GB 2 130 238 A 4 hard (2401-1) water.

The dialkyl sulphosuccinate used was a statistical mixture (mole ratio 1:2A) of di-n-octyl sulphosuccinate, n-hexyl n-octyl sulphosuccinate and di-n-hexyl sulphosuccinate (sodium salts), prepared from a 1: 1 mixture of n-hexanol and n-octanol by the method described in Example 1 of 5 GB 2 108 520 (Unilever).

The ether sulphate according to the invention was Dobanol 23-3A ex Shell (50% C12, 50% C13; n = 3; ammonium salt) while the comparison material was Dobanol 25-3A ex Shell (25% each of C121 C131 Cl, and Cl.; n = 3; ammonium salt).

The total active detergent concentration in each formulation tested was 25%.

The results obtained were as follows:

A B (a) Sulphosuccinate 20 16.6 (b) Dobanol 25-3A 5 8.3 (b) Dobanol 23-3A Ratio (a):(b) 4:1 2:1 1 2 3 16.6 12.5 8.3 12.5 4:1 2:1 1:1 Performance 29 20 28 23 Comparison of Compositions A and B (outside the invention) shows that a reduction in the (a):(b) ratio from 4:1 to 2:1 gives a considerable performance reduction. When Compositions 1, 2 and 3 according to the invention are compared it may be seen that at 2:1 the performance is not significantly 15 worse than at 4: 1, and even at 1: 1 it has not fallen as low as that of Composition B. EXAMPLE 4

Example 2 was repeated using Dobanol 23-2A (having n = 2 but otherwise identical to Dobanol 23-3M in both hard and soft water. The results were as follows:

2 (a) Sulphosuccinate (b) Dobanol 23-3A (b) Dobanol 23-2A Ratio (a):(b) 4 16.6 16.6 8.3 8.3 2:1 2:1 Performance 240C 5111-1 28 28 33 31 No significant difference in performance was observed.

EXAMPLES 5 & 6 The hard water performance of the dialkyl sulphosuccinate/Dobanol 23-3A system at an (a):(b) ratio of 2:1 was compared with those of similar systems containing three other alkyl ether sulphates, the tests being carried out at product dosages of both 1.0 and 1.5 g/litre. The ether sulphates used were Dobanol 23-3A and Dobanol 25-3A as in Example 1; Empimin 3003 ex Albright & Wilson, as used 25 in GB 1 429 637 (Unilever) discussed previously, and Dobanol 23-6.5A ex Shell, which has an average degree of ethoxylation of 6.5 but is otherwise similar to Dobanol 23-3A. The chain length distributions of all these materials are given in Table 1 previously. Each test formulation contained 16% by weight of the dialkyl sulphosuccinate mix used in earlier Examples and 8% by weight of the ether sulphate.

The results were as follows:

JI GB 2 130 238 A 5 Performance at 2411H Alkyl ether sulphate (b) 1.0 g/litre 1.5 g/litre c Dobanol 25-3A 20 33 D Empimin 3003 23 34 5 Dobanol 23-3A 27 40 6 Dobanol 23-6.5A 28 45 The results obtained at a product dosage of 1.0 g/litre show a similar effect to that observed in Examples 1-3, with Compositions 5 and 6 according to the invention being clearly superior to 10 Comparative Compositions C and D.

23-3A.

The higher-ethoxylated material Dobanol 23-6.5A gave even better results than Dobanol EXAMPLES 7-9

Fully formulated compositions containing the sulphosuccinate mix of previous Examples and various ether sulphates were prepared and their physical characteristics were measured. Comparative 15 Compositions A1 and A2 correspond in active detergent constituents and levels to Comparative Composition A in Examples 1 to 3, and Composition 5 here corresponds to Composition 5 of Example 5. Dobanol 23-2S is the sodium salt corresponding to Dobanol 23- 2A used in Example 4.

9 (a) Sulphosuccinate (b) Dobanol 25-3A (b) Dobanol 23-3A (b) Dobanol 23-2A (b) Dobanol 23-2S Urea A1 4:1 -7 96 A2 12 4:1 Unstable at room temp.

16 8 12 2:1 24 -8 138 7 16 8 12 2:1 24 Clear to -10 166 8 16 8 12 2:1 24 -8 153 Ethanol Ratio (a):(b) Total active detergent Cloud point (C) 27 13 12 6 2.08:1 Viscosity (cp) + 1 Comparative Example A1 shows a 4:1 dialkyl sulphosuccinate/ether sulphate composition outside 20 the invention; the relatively high level (20%) of hydrotrope will be noted. Comparative Example A2 shows that when an attempt was made to reduce that level to 12%, a completely unstable product was obtained. Stability was regained only by reducing the sulphosuccinate to ether sulphate ratio to 2:1, as in Compositions 5, 7 and 8 according to the invention. These Compositions also exhibited the advantageous attribute of higher viscosity.

Composition 9 according to the invention, having a higher active detergent level, required some ethanol as well as urea to achieve a low cloud point, and the viscosity was lower, but not unacceptably SO.

6 GB 2 130 238 A 6 EXAMPLES 10 & 11 The effect on performance of including a nonionic detergent in compositions of the invention was investigated in both hard and soft water, at a dosage of 1.0 g/litre.

The nonionic detergent used was Dobanol 91-8 ex Shell, which as mentioned previously is C,-Cl, predominantly straight-chain primary alcohol with an average degree of ethoxylation of 8. The 5 ratio of sulphosuccinate to the other detergents was 2:1 in each case, the total active detergent concentration being 27%.

The results were as follows Sulphosuccinate 18 Dobanol 23-3A 9 Dobanol 91-8 Performance 240H 30 W1-1 39 11 18 6 3 32 39 No significant difference in performance was observed.

EXAMPLE 12

A composition according to the invention containing an additional ingredient - primary alkyl sulphate - was prepared. This latter material was Dobanol 23-A ex Shell, which is the unethoxylated analogue of Dobanol 23-21A. The composition contained 12% by weight of the dialkyl sulphosuccinate 15 mix used in previous Examples, 8% by weight of Dobanol 23-A, and 8% by weight of Dobanol 23-21A. It required only 4% by weight of urea to achieve a cloud point of -41C, and its viscosity 430 cp - was high. The foaming performance in hard water, as demonstrated by the plates test at a dosage of 1.0 g/litre, was comparable to that of similar compositions containing no alkyl sulphate.

Claims

1. A foaming liquid detergent composition in the form of a stable aqueous solution containing at 20 least 2% by weight of an active detergent mixture comprising a) a water-soluble salt of a dialkyl ester of sulphosuccinic acid in which the alkyl groups may be the same or different, and b) a C,,-C,, primary alkyl polyethoxy sulphate containing 20% by weight or less of material of C14 and above chain length and having an average degree of ethoxylation of from 1 to 12, 25 the weight ratio of (a) to (b) being within the range of from 5:1 to 0.5A.

2. A detergent composition as claimed in claim 1, wherein the alkyl polyethoxy sulphate (b) contains less than 10% of material of C14 and above chain length.

3. A detergent composition as claimed in claim 2, wherein the alkyl polyethoxy sulphate (b) is substantially free of material of C,4 and above chain length.

4. A detergent composition as claimed in any one of claims 1 to 3, wherein the alkyl polyethoxy sulphate (b) has an average degree of ethoxylation of from 1 to 8.

-1

5. A detergent composition as claimed in claim 4, wherein the alkyl polyethoxy sulphate (b) has an average degree of ethoxylation of from 6 to 7.

6. A detergent composition as claimed in claim 4, wherein the alkyl polyethoxysulphate (b) has an 35 average degree of ethoxylation of from 2 to 3.

7. A detergent composition as claimed in any one of claims 1 to 6, wherein the alkyl polyethoxy sulphate (b) is derived from straight-chain or predominantly straight- chain aliphatic alcohols.

8. A detergent composition as claimed in any one of claims 1 to 7, which contains from 2 to 60% by weight of the active detergent mixture.

9. A detergent composition as claimed in claim 8, which contains from 5 to 40% by weight of the active detergent mixture.

10. A detergent composition as claimed in any one of claims 1 to 9, wherein the ratio of (a) to (b) is within the range of from 4:1 to 1:1.

11. A detergent composition as claimed in claim 10, wherein the ratio of (a) to (b) is within the 45 range of from 3:1 to 1 A.

12. A detergent composition as claimed in any one of claims 1 to 11, wherein the dialkyl sulphosuccinate (a) constitutes at least 5% by weight of the total composition.

13. A detergent composition as claimed in any one of claims 1 to 12, wherein the alkyl groups of 50 the dialkyl sulphosuccinate (a) each have from 4 to 10 carbon atoms.

Z f.

so 7 GB 2 130 238 A 7

14. A detergent composition as claimed in claim 13, wherein the alkyl groups of the dialkyl sulphosuccinate (a) each have from 6 to 8 carbon atoms.

15. A detergent composition as claimed in any one of claims 1 to 14, wherein the active detergent mixture further comprises an ethoxylated nonionic detergent having an alkyl chain length of C. to C, and an average degree of ethoxylation of from 5 to 14.

16. A detergent composition as claimed in claim 15, wherein the ratio of the alkyl polyethoxy sulphate (b) to the nonionic detergent is at least 1A.

17. A detergent composition as claimed in claim 1, substantially as described in any one of Examples 1 to 12 herein.

Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1984. Published by the Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.

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