GB2235207A - Detergent composition - Google Patents

Abstract

A detergent composition comprising at least one detergent active and a polyethylene glycol of a molecular weight of 400-5000. The addition of certain polyethylene glycols to detergent compositions has been found to give a lather enhancement effect.

Description

DETERGENT COMPOSITION The present invention relates to detergent compositions comprising lather enhancers. In particular it relates to the addition of linear molecules, for example polyethylene glycol to detergent compositions to enhance the lather thereof.

The detergent compositions of the present invention are intended for use by hand in personal, fabric or surface washing. The composition can be in the form of bars or pastes for personal use or for direct application to surfaces to be washed, or in the form of powders for dissolution to form a wash liquor.

With such compositions consumers generally judge the quality of a product on the foaming or lathering power thereof, even though low lathering detergent compositions may have a similar detergency to high lathering ones. To be acceptable to the consumer therefore a detergent composition intended for use by hand preferably has a high stability and rate of generation of lather.

Lather generation and stability generally depend on the concentration of detergent active, the detergent active type, the hardness of the wash water and the quantity and type of soil being washed.

In toilet bars, laundry bars and powder compositions there is a desire to reduce the active content of the composition since this can lead to cost savings. However reduced active levels can cause a deterioration in the quantity of lather produced which may be unacceptable to the consumer. It is also desirable to form bars and powders with mixed detergent active systems to improve the overall detergency performance particularly on oily soils but again this may lead to reduced lather generation depending on the active combination selected.

In laundry bar, paste and powder compositions there may also be a political, ecological or economic need to vary the detergent active mix for example to use greater quantitites of an indigenous detergent active or exchange a conventional detergent active for one which is more readily available. Such changes in the active type can lead to reduced lather generation which, as has already been stated, is unattractive to the consumer. It may also be desirable to alter the detergent active mixture in a composition in order to make it more effective under certain conditions, for example in a hard water area.

In addition to these problems there is also a desire to produce detergent compositions with increased lather generation and stability than has previously been provided.

In British Patent GB 2 037 804B (Lion Corporation/ FUKANO) there are disclosed certain enzyme-containing detergent composition comprising polyethylene glycol of molecular weight from 1000 to 20,000 to retain a good foaming power.

In West German Patent DE 3 640 541B (Henkel) there is disclosed a phosphate free non-soap detergent bar comprising polyethylene glycol of molecular weight 1,000 to 10,000 to increase the breaking strength and surface smoothness of the bars.

We have found that the incorporation of certain linear molecules e.g. selected polyethylene glycols makes it possible to avoid the choice constraints and concentration of active constraints referred to above while maintaining satisfactory lathering properties.

Accordingly a first aspect of the present invention provides a detergent composition comprising: (i) at least one detergent active; and (ii) a polyethylene glycol of molecular weight in the range 400 to 5000.

By including polyethylene glycol of molecular weight in the range 400 to 5000 in the composition the detergent active level or type may be altered while maintaining acceptable lathering properties. The polyethylene glycol is preferably present in an amount from 0.1 to 10% by weight of the composition. More preferably 1% or from 5 to 7% by weight of the composition.

Preferably the polyethylene glycol has a molecular weight in the range of from about 1000 to 2500 e.g. about 1100 to 2000 or 1500.

Whilst not wishing to be bound by any theory it is thought that certain linear molecules have this advantageous effect due to detergent active-linear molecule interactions which favour preferred active phase formation in the wash liquor.

The detergent active employed in the composition is preferably present in an amount of 3 to 60% by weight, more preferably 5 to 45% by weight.

Detergent actives suitable for use in the present invention are soaps for example the salts of higher fatty acids. This class of compound includes ordinary alkali metal soaps such as sodium, potassium ammonium, and alkylol ammonium salts of higher fatty acids containing from about 8 to about 24 carbon atoms and preferably from about 12 to about 22 carbon atoms. Soaps can be made by direct saponification of fats and oils or by neutralisation of free fatty acids. Particularly useful are the sodium and potassium salts of mixtures of fattv acids derived from coconut oil, tallow, fish oil, soya oil, e.g. sodium and potassium tallow soap.

Other suitable detergent actives are non-soap detergent actives such as alkyl benzene sulphonate having 8 to 22 carbon atoms in the alkyl group, C8 to C18 primary alcohol sulphate, or C8 to C18 fatty acid C1 to C4 ether sulphonate. Various other non-soap detergent actives may be used for example alkyl sulphates, alkyl ether sulphates and olefin sulphonates. Particularly preferred non-soap detergent actives are linear alkyl benzene sulphonates (LAS) and branched chain alkyl benzene sulphonates (ABS).

Nonionic detergent actives such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenol ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid ester polyoxyethylene ethers, sucrose fatty acid esters, fatty acid alkylolamides and the like; ampholytic detergent actives such as betaine types.

The detergent compositions also contain optional ingredients such as organic detergency builders and inorganic detergency huilders. The detergency builder is preferably present in an amount from 5 to 60% by weight more preferably from 5 to 10% by weight. Examples of suitable inorganic builders are water-soluble sulphonates, water-soluble phosphates, water-soluble carbonate, water soluble silicates and alumino silicates (zeolite).

Other optional ingredients comprise fillers such as sodium sulphate, talc, kaolin, calcite and bentonite; redeposition preventing agents such as carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA) and the like; optical brightening agents; bleaching agents; colouring agents and perfumes.

Compositions according to the invention can be produced using conventional techniques. For example in the case of laundry or toilet bars the bars are prepared by progressively mixing the ingredients with water (where appropriate) using a shear mixer and then extruding. In the case of detergent powders the powder may be produced by spray-drying a slurry or dry mixing powdered constituents.

The invention will now be described and further exemplified in the following examples in which percentages are by weight.

Example 1 The lather enhancement effect of polyethylene glycol of various molecular weights was assessed by subjecting formulations 1A to 1E to a minifoameter test in 12"FH water. The minifoameter comprises a foam generation cell, having at its base a motor driven impeller, and at its top a graduated plunger to determine foam volume. The test 3 comprises placing 25cm3 of test solution in the cell and subjecting the test solution to 20 seconds (2500 rpm) of impellar action. The plunger is then inserted in the cell and the foam heigh measured.

The formulations were formed into bars by mixing in a Winkworth Z-blade mixer at a temperature of 800C. Tallow distilled fatty acids were neutralised with 47% w/w sodium hydroxide. The appropriate PEG or surfactant was added followed by any additional water. Kaolin and solid anhydrous sodium orthophosphate were then added. The resulting dough was cooled to room temperature and extruded into billets which were wrapped in glassine paper.

Formulation wt % Ingredient 1A 1B 1C 1D 1E Tallow Soap 26.40 26.40 26.40 26.40 26.40 Coconut Soap 6.6 - - - Sodium orthophosphate 13.00 11.00 11.00 11.00 11.00 Kaolin 22.00 36.00 36.00 36.00 36.00 Water 32.00 20.00 20.00 20.00 20.00 PEG 400 - 6.6 - - PEG 1500 - - 6.6 - PEG 35000 - - - 6.6 PEG 200000 - - - - 6.6 Foam Height at product concentration of 10g/l (cm) 13.50 9.00 13.70 8.00 11.00 PEG denotes polyethylene glycol. The number following denotes molecular weight.

These results show the lather enhancing effect of PEG 1500 in formulation 1C compared to PEGs of other molecular weights as in formulations 1B, 1D and lE.

Comparison of the foam heights obtained for formulations 1A and 1C shows that similar foam heights are obtainable by the substitution of 6.6% detergent active for 6.68 PEG 1500.

Example 2 The lather enhancement effect of polyethylene glycol of molecular weight 1500 on alternative and mixed detergent active systems was assessed by subjecting the following formulations to a cylinder shake test. The formulations were first formed into bars by forming a dough and plodding into bars using conventional techniques. 2.0g of bar was grated directly into a 50ml beaker containing 25mls of water. The contents were stirred for 10 to 15 minutes and then poured into a 100ml measuring cylinder. The cylinder was shaken 25 times and the foam height measured immediately and after one minute shaking.

Formulation wt% Ingredient 2F 2G 21 Petrolab 550 LAS acid 20.00 15.00 15.00 Soda Ash 9.00 9.00 9.00 Water 5.00 5.00 5.00 Alkaline Silicate (48% solid) 6.50 6.50 6.50 Aluminium sulphate 14.5 H2O 5.00 5.00 5.00 STP 8.00 8.00 8.00 Sodium sulphate 12.00 12.00 12.00 Calcite 17.10 17.10 17.10 Kaolin 17.00 17.00 17.00 Perfume 0.40 0.40 0.40 PEG 1500 - 5.00 lIES AOS - - 5.00 Foam height (mm) 103.00 140.00 135.00 LAS denotes linear alkyl benzene sulphonate AOS denotes alpha olefin sulphonate STP denotes sodium tripolyphosphate These results show the lather enhancing effect of PEG 1500 in laundry bar. Comparison of formulations 2F and 2G shows an increase in lather despite a 5% decrease in active level from 2F to 2G. Comparison of formulation 21 with 2G show the lather enhancing effect of replacing 5% LAS with AOS.

Example 3 The effect of polyethylene glycol of molecular weight 1500 on the rate of lather generation was assessed by subjecting the formulations 2F, 2G, and 21 of Example 2 to a lather generation handwash test. The lather generation handwash test comprises soaking standard test cloths in a dispersion of lg/l sebum in 200FH water at approximately 200C at a liquor to cloth ratio of 4:1. The wet test cloth is then laid on a corrugated wash board on a metal tray. A bar which has been conditioned by twisting through 1800 4 times by hand under cold running water is then applied to the cloth so as to smear 0.9g of product onto the cloth. The cloth is then folded and rubbed/rolled over the board for 10, 20, 30, 40 or 60 seconds. The resulting lather is squeezed from the cloth and measured by pouring into a measuring cylinder.A plot of lather volume versus time may then be drawn (Figure 1).

Figure 1 shows the improvement in lather generation brought about by the replacement of 5% LAS by PEG 1500 under conditions of oily soil.

Example 4 The lather enhancement effect of polyethylene glycols of various molecular weights was assessed by subjecting the following formulations to a "hand wash" test. The 'hand wash' test comprised soaking two desized cloths treated with 2ml of a standard soil emulsion* in a detergent solution made up from a concentration of 0.78 of the formulations A to E given below. The cloth to liquor ratio was 1:3.5. The cloth was soaked for 15 minutes and then kneaded 20 times. The volume of lather generated was measured along with the liquor in a 500ml measuring cylinder.

Formulation wtt Ingredient A B C D E LAS 5.0 5.0 5.0 5.0 5.0 STPP 8.33 8.33 8.33 8.33 8.33 Soda Ash 50.00 50.00 50.00 50.00 50.00 Salt 15.00 15.00 15.00 15.00 15.00 Sodium sulphate (anhydrous) 13.00 13.00 13.00 13.00 13.00 Colour, perfume 1.35 0.35 0.35 0.35 0.35 NDOM + moisture 7.32 7.32 7.32 7.32 7.32 PEG mw 400 - 1 - - PEG mw 1500 - - 1 - PEG mw 4000 - - - 1 PEG mw 6000 - - - - 1.00 100.00 100.00 100.00 100.00 100.00 Lather (ml) 70.00 68.00 83.00 68.00 75.00 LAS denotes linear alkyl benzene sulphonate STPP denotes sodium tripolyphosphate PEG denotes polyethylene glycol MW denotes molecular weight NDOM denotes non-detergent active organic matter These results show the surprisingly good lather enhancing effect of PEG 1500 in formulation C compared to PEGs of other molecular weights in formulations B, D and E.

Example 5 The lather enhancement effect of polyethylene glycol of molecular weight 1500 on alternative detergent active systems was assessed by subjecting the following formulations to the hand wash test described in Example 1 except that formulations F to I given below were used.

Formulation wt% Ingredient F G H I LAS 20.00 - - AOS - 20.00 24.00 20.00 PEG 1500 - - - 1.5 STPP 22.00 22.00 22.00 22.00 Water 12.00 12.00 12.00 12.00 Soda 10.00 10.00 10.00 10.00 Alkaline sodium silicate 10.00 10.00 10.00 10.00 Sodium sulphate (anhydrous) 18.45 18.45 14.45 16.95 Calcite 5.00 5.00 5.00 5.00 Colour, perfume etc 2.55 2.55 2.55 2.55 100.00 100.00 100.00 100.00 Soil Lather (ml) 243.00 215.00 250.00 243.00 AOS denotes alpha olefin sulphonate.

These results show the lather enhancing effects of PEG 1500 in a system other than LAS. Comparison of the lather heights of formulations G and I shows the lather enhancing effect of PEG 1500. Comparison of the lather heights of formulations H and I shows that the percentage of AOS may be reduced with the addition of 1.5% PEG 1500 without compromising the lathering properties of the powder.

Example 6 The lather enhancement effect of polyethylene glycol of molecular weight 1500 on mixed detergent active systems was assessed by subjecting the following formulations to the hand-wash trial of Example 1.

Formulation wtZ Ingredient J K LAS 17.00 8.00 AOS - 9.00 PEG 1500 - 1.50 Soda Ash 25.00 25.00 Silicate 8.00 8.00 Salt 5.00 5.00 Calcite 10.00 10.00 Sodium sulphate anhydrous 29.90 28.4 Colour etc. 1.25 1.25 NDOM + moisture 3.85 3.85 100.00 100.00 Soil Lather (ml) 250.00 247.00 These results show that a mixed active system with PEG 1500 can achieve comparable lather to an all LAS active system.

Example 7 The lather enhancement effect of polyethylene glycol of molecular weight 1500 (PEG 1500) in laundry bars was assessed by forming formulations L and M below into bars and subjecting the bars to a 'rub-down' test. The formulations were formed into bars by shear mixing the ingredients to form a dough followed by extrusion to form a billet. The 'rub-down' test comprises rubbing the bar on a wetted and presoaked fabric in a controlled manner followed by kneading and squeezing the fabric to collect the lather generated in a measuring cylinder.

Formulation wt% Ingredient L M AOS 20.00 20.00 PEG 1500 1.00 STPP 16.70 16.70 Soda Ash 4.00 4.00 Na silicate 4.50 4.50 Calcite + Whiting 40.00 41.00 Water 8.20 8.20 NDOM + minors 3.60 3.60 100.00 100.00 Lather in soil (ml) 93.00 66.00 STPP denotes sodium tripolyphosphate These results show the lather enhancement effect of PEG 1500 in laundry bar formulations.

Example 8 The following compositions were prepared in the laboratory and lather values evaluated by "cylinder shake" method: ig gratings were taken in a dry stoppered tube (length 9", diameter 1"), 5ml distilled water is added to it and the contents shaken vigorously for 30 secs. to generate lather. Lather generated is measured as lather height in ism".

N P Q R S LAS 14 - 12 10 7 PEG 1500 - 14 2 4 7 Soda Ash 5 5 5 5 5 STPP 10 10 10 10 10 Calcite 60 60 60 60 60 Lather Values 8.3 4.5 11.5 11.7 11.5

Claims (8)

1. Claims 1. A detergent composition comprising (i) at least one detergent active; and (ii) a polyethylene glycol of molecular weight in the range 400 to 5000.
2. 2. A detergent composition as claimed in claim 1 wherein the composition comprises from 0.1 to 10% by weight of polyethylene glycol.
3. 3. A detergent composition as claimed in claim 1 or claim 2 wherein the composition comprises from 5 to 7% by weight of polyethylene glycol.
4. 4. A detergent composition as claimed in any preceding claim wherein the polyethylene glycol has a molecular weight in the range of from about 1000 to 2500.
5. 5. A detergent composition as claimed in any preceding claim wherein the polyethylene glycol has a molecular weight from about 1100 to 2000, preferably 1500.
6. 6. A detergent composition as claimed in any preceding claim wherein the composition comprises from 3 to 60% by weight of detergent active.
7. 7. A detergent composition as claimed in any preceding claim wherein the composition comprises from 5 to 45% by weight of detergent active.
8. 8. A detergent composition as claimed in any preceding claim in the form of a bar.