SURFACTANT SYSTEMS

Abstract

The invention provides a surfactant system, for use in household detergent compositions, which is a mixture of: (i) at least one sulfonate-functionalized alkyl polyglycoside of general formula (I):

R—O-(G).sub.n-(D)   (I) in which: p0 R represents a straight or branched chain monovalent hydrocarbyl radical having from 6 to 22 carbon atoms; G represents a residue of a reducing saccharide, connected to R—O by means of an ethereal O-glycosidic bond; n represents a number from 1 to 10; and D represents a —CH.sub.2CH(OH)CH.sub.2—SO.sub.3M group connected to an oxygen atom of G, where M is selected from H or a monovalent cation selected from Na, K, or NH.sub.4; and (ii) at least one ethoxylated fatty acid sorbitan ester of general formula (II):

Sorb-(EO.sub.n1R.sub.1)(EO.sub.n2R.sub.2)(EO.sub.n3R.sub.3)(EO.sub.n4R.sub.4)   (II) in which: Sorb represents a residue obtained by removing four hydroxyl H atoms from sorbitan; EO represents an ethyleneoxy group; R.sub.1, R.sub.2, R.sub.3 and R.sub.4are each independently selected from H or a —C(O)R.sub.5 group in which R.sub.5 is selected from straight or branched chain monovalent hydrocarbyl radicals having from 8 to 22 carbon atoms and mixtures thereof (provided that at least one of R.sub.1 to R.sub.4 is —C(O)R.sub.5); n.sub.1, n.sub.2, n.sub.3 and n.sub.4 each independently represent average values from 0 to 10; and the total [n.sub.1+n.sub.2+n.sub.3+n.sub.4] has an average value from 4 to 30; and in which the weight ratio of (i):(ii) in the mixture ranges from 5:1 to 1:5.

Claims

1. A surfactant system, for use in household detergent compositions, which is a mixture of (i) at least one sulphonate-functionalised alkyl polyglycoside selected from sodium laurylglucosides hydroxypropyl sulfonate or sodium decylglucosides hydroxypropyl sulfonate and mixtures thereof and (ii) at least one ethoxylated fatty acid sorbitan ester with an average ethoxylation of 15-25.

2. A surfactant system according to claim 1 in which the: (i) at least one sulfonate-functionalized alkyl polyglycoside has general formula (I):
R—O-(G).sub.n-(D)   (I) in which: R represents a straight or branched chain monovalent hydrocarbyl radical having from 6 to 22 carbon atoms; G represents a residue of a reducing saccharide, connected to R—O by means of an ethereal O-glycosidic bond; n represents a number from 1 to 10; and D represents a —CH.sub.2CH(OH)CH.sub.2—SO.sub.3M group connected to an oxygen atom of G, where M is selected from H or a monovalent cation selected from Na, K, or NH.sub.4; and (ii) the at least one ethoxylated fatty acid sorbitan ester has general formula (II):
Sorb-(EO.sub.n1)(EO.sub.n2R.sub.2)(EO.sub.n3R.sub.3)(EO.sub.n4R.sub.4)   (II) in which: Sorb represents a residue obtained by removing four hydroxyl H atoms from sorbitan; EO represents an ethyleneoxy group; R.sub.1,R.sub.2,R.sub.3 and R.sub.4 are each independently selected from H or a —C(O)R.sub.5group in which R.sub.5 is selected from straight or branched chain monovalent hydrocarbyl radicals having from 8 to 22 carbon atoms and mixtures thereof (provided that at least one of R.sub.1 to R.sub.4 is —C(O)R.sub.5); n.sub.1, n.sub.2, n.sub.3 and n.sub.4 each independently represent average values from 0 to 10; and the total [n.sub.1+n.sub.2+n.sub.3+n.sub.4] has an average value from 15-25.

3. The surfactant system according to claim 1 in which the weight ratio of (i):(ii) in the mixture ranges from 5:1 to 1:5.

4. The surfactant system according to claim 1, in which the sulfonate functionalized alkyl polyglycosides (i) are selected from sodium laurylglucosides hydroxypropyl sulfonate and sodium decylglucosides hydroxypropyl sulfonate and mixtures thereof; the ethoxylated fatty acid sorbitan esters (ii) are selected from polyoxyethylene* (20) sorbitan monolaurate, polyoxyethylene (20) sorbitan monopalmitate, polyoxyethylene (20) sorbitan monostearate, polyoxyethylene (20) sorbitan monooleate and mixtures thereof; and the weight ratio of (i) to (ii) in the mixture ranges from 4:1 to 1:2.

5. A laundry detergent composition including the surfactant system according to claim 1.

6. The laundry detergent composition according to claim 5, in which the total combined level of sulfonate-functionalized alkyl polyglycoside (i) and ethoxylated fatty acid sorbitan ester (ii) ranges from 10 to 90% (by weight based on the total weight of the composition).

7. The laundry detergent composition according to claim 6, in which the level of sulfonate-functionalized alkyl polyglycoside (i) ranges from 3 to 40% (by weight based on the total weight of the composition) and the level of ethoxylated fatty acid sorbitan ester (ii) ranges from 1 to 35% (by weight based on the total weight of the composition).

8. The laundry detergent composition according to claim 7, which further comprises from 1 to 10% (by weight based on the total weight of the composition) of organic builders and/or sequestrants selected from polycarboxylates, in acid and/or salt form.

9. The laundry detergent composition according to claim 6, in which the organic builder and/or sequestrant is sodium citrate.

10. A surfactant system or laundry detergent substantially as hereinbefore described.

Description

EXAMPLES

[0077] All weight percentages are by weight based on total weight unless otherwise specified.

[0078] A series of surfactant mixtures were prepared with ingredients and ratios as shown below in Table 1:

TABLE-US-00001 TABLE 1 wt. % Ingredient (active ingredient) Formulation Ex. 1 Ex. 2 Ex. 3 polyoxyethylene (20) sorbitan monolaurate 6.9 11.5 3 sodium decylglucosides hydroxypropylsulfonate .sup.(1) 8.1 13.5 12 sodium citrate 4 4 4 EPEI.sup.(2) 3 3 3 SRP 1 1 1 Demineralised water q.s. to 100 .sup.(1) Suga ®Nate 100NC, ex Colonial Chemicals .sup.(2)Sokalan ®HP20, ex BASF

[0079] Polyester test fabrics and cotton test fabrics stained with a range of standard stains were washed with a 2.3g/L aqueous solution of each of Examples 1,2 and 3 according to the invention. A commercially available formulation (UK Persil™ Non-Bio liquid laundry detergent) at the same level of dilution was used as a control (not according to the invention).

[0080] The extent of stain removal was measured by making diffuse reflectance measurements using a spectrometer, and expressed as the Stain Removal Index (SRI), defined as:

[0081] SRI=100−ΔE, where ΔE is the difference in colour of the stained test fabric compared to the unstained test fabric.

[0082] A higher SRI value indicates cleaner fabric. The results are shown in Table 2.

TABLE-US-00002 TABLE 2 Test formulation 1 2 3 Control Test stain/fabric Stain removal index (SRI) red soil/polyester 77.4 76.6 75.6 75.2 red wine/cotton 84.7 85.9 85.2 86.4 cooked beef fat/polyester 85.8 86.8 86.6 89.6

[0083] The results show that Examples 1,2 and 3 according to the invention provide parity performance against most of the standard stains when compared with the control.

[0084] A further series of surfactant mixtures were prepared with ingredients and ratios as shown below in Table 3:

TABLE-US-00003 TABLE 3 Ingredient wt. % (active ingredient) Formulation A B C D 4 5 C.sub.12-14 LAS 5.8 3.3 12.1 16 SLES (3EO) 4.4 10 C.sub.12-15 alcohol ethoxylate (7EO) 4.4 0.8 1.2 CAPB 1.9 sodium laurylglucosides 10 5 hydroxypropylsulfonate.sup.(3) polyoxyethylene (20) sorbitan 5 10 monopalmitate water q.s. to 100 .sup.(3)Suga ®Nate 160NC, ex Colonial Chemicals

[0085] Examples 4 and 5 are examples according to the invention. Examples A,B,C and D are comparative examples (not according to the invention).

[0086] The formulations from Table 3 were tested in a Zein Assay. A low number indicates a milder formulation. The assay scores are shown below in Table 4.

TABLE-US-00004 TABLE 4 Formulation Absorbance at 590 nm for 20 g/L product A 0.782 B 1.697 C 0.987 D 1.549 4 0.299 5 0.122

[0087] The results show that Examples 4 and 5 according to the invention provide superior mildness when compared with Examples A to D (not according to the invention).