GB2148926A

GB2148926A - Detergent composition

Info

Publication number: GB2148926A
Application number: GB8424699A
Authority: GB
Inventors: Richard Buscall; Roger Ian Hancock; Kathleen Schofield
Original assignee: Imperial Chemical Industries Ltd
Current assignee: Imperial Chemical Industries Ltd
Priority date: 1983-10-27
Filing date: 1984-10-01
Publication date: 1985-06-05
Also published as: GB2148926B; AU569118B2; AU3413884A; GB8328708D0; GB8424699D0

Abstract

Liquid detergent compositions in the form of aqueous emulsions comprise an alkoxylated alkylphenol and/or an alkoxylated alkanol surfactant, an aqueous solution of a detergent builder as the continuous phase and, where the surfactant is an alkoxylated alkanol, a low molecular weight polyethylene oxide.

Description

SPECIFICATION Detergent composition This invention relates to liquid detergent compositions, particularly to such compositions in which the surfactant is non-ionic.

It is known from US 4,348,292 to prepare liquid detergent compositions having two separate layers of liquid composition the first of which comprises a surfactant and the second of which comprises an aqueous solution of a detergent builder.

It is known from US 4,289,492 to prepare liquid detergent compositions in the form of clear isotropic solutions which comprise an ionic surfactant, sodium tripolyphosphate and tetrapotassium pyrophosphate as detergent builder, an alkali metal fatty acid soap and an alkanolamine.

Homogeneous aqueous liquid detergent compositions comprising an anionic surfactant, an alkali metal soap of a fatty acid and an non-ionic surfactant are known in the art, e.g. from European patent application publication No. 38101.

Alkoxylated alkylphenols and alkoxylated alkanols which are soluble in or miscible with water are rendered insoluble by the addition of certain alkali metal phosphates to aqueous solutions thereof. The concentration of the certain alkali metal phosphates required to effect precipitation depends upon the chemical structure of the alkali metal phosphate, the chemical structure of the alkoxylated alkylphenol or alkoxylated alkanol and the temperature of the aqueous solution. For surfactants of the type suitable for use in detergent compositions and for soluble phosphates such as sodium tripolyphosphate or sodium orthophosphate the concentration of phosphate required to render the surfactant insoluble is typically not more than 1% w/w.We have found that certain alkoxylated alkylphenols and certain alkoxylated alkanols can be mixed with aqueous solutions of detergent builders in which they are insoluble to afford liquid detergent compositions in the form of emulsions of droplets of the alkoxylated alkylphenol or alkoxylated alkanol in a continuous phase of the aforesaid aqueous solution, which detergent compositions are stable and pourable.

We have found that for any particular emulsion of droplets of an alkoxylated alkylphenol or slkoxylated alkanol in a continuous phase of an aqueous solution of a phosphate there is a critical concentration of soluble phosphate above which the emulsions are unstable. This critical concentration depends upon the chemical structure of the phosphate and the alkoxylated alkylphenol or alkoxylated alkanol, it is typically between 10 and 30% w/w. We have found that the range of soluble phosphate concentrations over which stable emulsions can be formed can be widened by the addition of low molecular weight polyethylene oxides, which may be linear e.g. PEG with a molecular weight of 200, or branched, for example derived from a polyol, e.g. trimethylolpropane or glycerol.The addition of low molecular weight polyethylene oxide affords the further advantage, when such advantage is desired, that the viscosity of the emulsion is lowered.

Accordingly, the present invention provides an aqueous liquid detergent composition in the form of an emulsion which comprises (a) droplets of a non-ionic surfactant which comprises an alkoxylated alkylphenol or alkoxylated alkanol, (b) a continuous phase which comprises an aqueous solution of a detergent builder and (c) where the non-ionic surfactant consists of an alkoxylated alkanol, a low molecular weight polyethylene oxide.

By "stable" we mean that the emulsions of the present invention may be stored for their useful working lives with little if any separation into discrete continuous phases. However, we do not exclude the possibility that some "creaming" may occur on storage of emulsions of the present invention by which we mean that a layer of discrete droplets of alkoxylated alkylphenol or alkoxylated alkanol forms on top of the emulsion which droplets may be readily redistributed homogeneously throughout the emulsion.

The alkoxylated alkylphenols used in the present invention are derived from C4-C16 alkylphenols, and preferably are derived from an octyl and/or a nonyl-phenol.

The alkoxylated alkanols used in the present invention are derived from C8-C18 straight or branched-chain alkanols, and preferably derived from alkanols having between 10 to 1 6 carbon atoms.

The alkoxyl residues in the alkoxylated alkylphenols and alkoxylated alkanols used in the present invention are substantially ethoxyl residues but we do not exclude the possibility that a small proportion of higher alkoxyl, e.g. propoxyl residues, say in a molar ratio of ethoxyl to propoxyl of more than 5:1 may be present. Preferably there are on average between 4 and 1 5 ethoxyl groups and, for alkylphenols, more preferably from 4 to 9 ethoxyl groups per alkylphenol or alkanol.

The non-ionic surfactant may comprise, in addition to the alkoxylated alkylphenol and alkoxylated alkanol, a further non-ionic surfactant which is not an alkoxylated alkylphenol or alkoxylated alkanol, e.g. a fatty acid alkanoiamide. Where the further non-ionic surfactant is present it may provide up to 60% by weight of the total non-ionic surfactant content of the aqueous liquid detergent composition according to the present invention.

The non-ionic surfactant typically provides between 5 and 50% w/w of the aqueous liquid detergent composition of the present invention.

The detergent builder used in the aqueous liquid detergent composition of the present invention is preferably a phosphate and more preferably is sodium tripolyphosphate although we do not exclude the possibility that it may comprise any of the known detergent builders, e.g.

nitriloacetic acid (NTA), ethylenediaminetetracetic acid (EDTA), sodium silicates, sodium and potassium hydroxides, citrates, carbonates and mixtures thereof.

Where the aqueous solution of a detergent builder used in the present invention is an aqueous solution of tripolyphosphate it is preferably a saturated solution thereof.

By low molecular weight polyethylene oxide we mean a polyethylene oxide in which at least 90%, and preferably substantially all, of the repeat units in the polymer chain are ethylene oxide residues and which has a number average molecular weight of up to 2000 and preferably between 100 and 800.

Where the aqueous liquid detergent composition according to the present invention contains a low molecular weight polyethylene oxide the concentration of the low molecular weight polyethylene oxide in the aqueous liquid detergent composition is typically less than 20% w/w and often is about 5 to 15 %w/w.

We have found that a water soluble detergent builder in particulate form, preferably a phosphate, may be dispersed or suspended in the emulsion to increase the concentration of detergent builder to up to about 30% w/w of the detergent composition.

Where a particulate detergent builder is present in the composition of the present invention the particles thereof preferably have a size of less than 200 microns.

Where there is a tendency for "creaming" of the aqueous liquid detergent composition according to the present invention to occur this can be at least alleviated by the addition thereto to a conventional anti-creaming agent which is soluble in the builder solution, e.g. dextran or similar polyhydroxyl polymer, e.g. polyvinyl alcohol, or preferably xanthan qum, either alone or in combination with a montmorillonite clay.

It will be appreciated that conventional detergent ingredients may be present in the aqueous liquid detergent composition according to the present invention, e.g. foam controls agents, stabilised bleach, fluorescent whitening agents, antiredeposition agents, corrosion inhibitors, enzymes, metal complexing agents, perfumes and dyestuffs.

Aqueous liquid detergent compositions according to the present invention may be used in conventional detergent applications, for example industrial and household cleansing. They may be used for cleansing hard surfaces, e.g. glass, metals and plastics, and particular fibrous materials, e.g. made of natural or synthetic fibres.

Aqueous liquid detergent compositions according to the present invention are pourable and have viscosities which depend upon the composition thereof and the method or preparation, as the method of emulsification affects the droplet size. They are stable to changes in temperature and will withstand storage at a temperature in the range - 5"C to + 50"C for their useful working lives.

Aqueous liquid detergent compositions according to the present invention may be prepared by any method of emulsification which provides intimate mixing of the liquid surfactant and the aqueous solution of the detergent builder. Thus, for example, high shear mixers, e.g. Greaves mixers and Silverson mixers, valve and jet homogenisers, e.g. "Manton-Gaulin", and static mixers, e.g. Kenics mixers, are suitable. Emulsification is preferably carried out in two steps; the first step is a coarse mixing step and the second step is a homogenisation step which may be carried out using, for example, an ultrasonic homogeniser. Where small volumes, say about 0.1 litres, of the aqueous liquid detergent composition according to the present invention are prepared, emulsification may be carried out in a single step using an ultrasonic device, e.g. an ultrasonic probe, or simple propeller mixers.

The present invention is further illustrated by reference to the following Examples.

Example 1 "Synperonic" NP4 (ex ICI:15 grams), an alkoxylated nonylphenol having on average a chain of four ethoxyl groups, was added with stirring to a solution of sodium tripolyphosphate (14.5 grams) and "Keltrol" (ex Kelco Corporation of San Diego, California, 0.5 grams), a xantham gum, in water (70 grams) and the mixture was homogenised using an ultrasonic probe. A stable emulsion was formed.

Example 2 Example 1 was repeated without the xanthan gum. An emulsion was obtained which was stable to coalescence but creamed over a period of a few days.

Example 3 Example 1 was repeated using a mixture of "Synperonic" NP4 (7.5 grams) and "Synperonic" NP9 (7.5 grams) instead of neat "Synperonic" NP4. "Synperonic" NP9 is an ethoxylated nonylphenol having a chain of about nine ethoxyl residues. A stable emulsion was obtained.

In a comparative test, neat "Synperonic" NP9 (15 grams) was used instead of the mixture of "Synperonic" NP4 and "Synperonic" NP9. An unstable emulsion was obtained, indicating that for use of neat "Synperonic" NP9 with sodium tripolyphosphate as builder the concentration of the aqueous builder solution should be less than about 15% w/w.

Example 4 Example 3 was repeated using a mixture of sodium tripolyphosphate (14 grams) and potassium orthophosphate (6 grams) instead of neat sodium tripolyphosphate (14. 5 grams) and 64.5 grams instead of 70 grams of water. A stable emulsion was obtained.

In a comparative test, the amount of potassium orthophosphate was increased to 1 6 grams and the amount of water was decreased to 54.5 grams. An unstable emulsion was obtained.

Example 5 Example 1 was repeated but using 40 grams of "Synperonic" NP4 instead of 1 5 grams. A stable emulsion was obtained.

Example 6 "Synperonic" NP4 (5 grams), "Synperonic" NP9 (5 grams) and a solution of sodium tripolyphosphate (14.5 grams) and "Keltrol" (0.5 grams) in water (75 grams) were passed repeatedly through a Kenics static mixer. A silvery coarse emulsion with a viscosity of 14 poise at a shear rate of 1 second1 and 2.8 poise at 100 seconds-' was obtained.

Sonication of the coarse emulsion for 1 minute produced a stable creamy white emulsion with a viscosity of 45 poise at 10 seconds-' and 6.5 poise at 100 seconds-'.

Example 7 Example 1 was repeated except that a mixture of PEG 200 (10 grams) and "Synperonic" A7 (15 grams), a mixture of alkoxylated C3 r5 alkanols having on average a chain of about 7 ethoxyl residues, was used instead of "Synperonic" NP4 (15 grams) and 60 grams of water was used instead of 70 grams. A stable emulsion was obtained.

In a comparative test, the experimental was repeated in the absence of the PEG 200 and using 70 grams of water instead of 60 grams. An unstable emulsion was obtained.

Example 8 Example 7 was repeated except that "Synperonic" Al 1, a mixture of alkoxylated C3 a5 alkanols having on average a chain of about 11 ethoxyl residues, was used instead of "Synperonic" A7. A stable emulsion was obtained.

In a comparative test, the experiment was repeated in the absence of the PEG 200 and using 70 grams of water instead of 60 grams. An unstable emulsion was obtained.

Example 9 Example 7 was repeated except that "Synperonic" K87, a mixture of alkoxylated C,3-C,5 alkanols having on average a chain length of approximately 7.5 moles of a mixture of 92% ethylene oxide and 8% propylene oxide (by weight), was used instead of "Synperonic" A7. A stable emulsion was obtained.

Example 10 Example 7 was repeated except that a mixture of "Synperonic" A3 (7.5 grams), a mixture of alkoxylated C3 a5 alkanols having on average a chain of about 3 ethoxyl residues, and Synperonic" All (7.5 grams) was used instead of "Synperonic" A7 (15 grams). A stable emulsion was obtained.

In a comparative test, the experiment was repeated in the absence of PEG 200 and using 70 grams of water instead of 60 grams. An unstable emulsion was obtained.

Example 11 Example 7 was repeated except that a mixture of "Synperonic" A3 (5 grams) and "Synperonic" K87 (10 grams) was used instead of "Synperonic" A7. A stable emulsion was obtained.

Example 12 Example 1 was repeated except that a mixture of "Synperonic" A3 (5 grams) and "Synperonic" K87 (10 grams) were used instead of "Synperonic" NP4 (15 grams), 10 grams instead of 14.5 grams of sodium tripolyphosphate were used, and 74.5 grams instead of 70 grams of water were used. A stable emulsion was obtained.

Example 13 Sodium tripolyphosphate (10 grams) was added to the emulsion (100 grams) prepared in Example 1. A stable composition which contained a suspension of particles of sodium tripolyphosphate in the emulsion was obtained.

Example 14 A 1 : 3 by weight mixture of "Synperonic" NP4 and "Synperonic" NP9 (10 grams) was added to a saturated aqueous solution (100 gram) of sodium tripolyphosphate (Empiphos STP-D ex Albright and Wilson) containing 0.4% w/w of a xanthan gum ("Kelzan" ex Kelco Corporation of San Diego, California) and homogenised using a high shear mixer. A stable formulation was obtained.

The formulation was tested for it detergency performance in a "Tergometer" at 100 r.p.m.

with a ten minute wash and no presoak. The results obtained, and those obtained in comparative tests with a commercially available built anionic based laundry liquid, are shown in Table 1, from which it can be seen that for cotton and polyester-cotton mixtures soiled with synthetic sebum very good cleaning was observed, and for polyester-cotton mixtures soiled with proteinaceous soil adequate cleaning was observed.

Table 1

Fabric Soil Temrature Water Increase in Reflectance C Hardness of Test Clothes (opm Example 14 Cararative Test Ca CO3) 5 gramstit 5 orams"litre C K 40 50 19.6 16.0 40 300 19.5 14.6 60 50 23.7 25.4 60 300 21.7 20.3 PC K 40 50 19.9 9.4 40 300 17.0 8.8 60 50 23.6 14.3 60 30D 22.3 10.1 PC E 40 50 30.7 45.4 40 300 12.4 41.6 60 50 2.2 31.4 60 300 6.4 32.9 Cotton C : Polyester-Cotton mixture Synthetic sebum (Krefeld soil) Proteinaceous soil (Empa 117) Example 15 A saturated aqueous solution (100 grams) of sodium tripolyphosphate containing 0.4 % w/w of a xanthan gum was shaken with a 1 : 3 by weight mixture (7.5 grams) of "Synperonic" NP9 and polyethylene glycol MW 200 (5 grams). A stable emulsion was obtained.

Solid sodium tripolyphosphate (15 grams) was mixed into the stable emulsion using a high shear mixer to give a stable, homogeneous, coarse suspension which was further homogenised by passage through a laboratory bead mill. A homogeneous viscous liquid was obtained which remained stable at 4"C, 25"C and 40"C for more than two weeks.

Example 16-19 The components indicated in Table 2 were emulsified to provide compositions according to the present invention.

TABLE 2

Example Saturated "Synperonic" PEG 200 'Relzane Stability No. STPP A3/K87 (grams) % w/w solution 1/3 by weight (grams) (grams) 16 80 10 10 0.4 > 21 days 17 70 10 10 0.3 > 21 days 18 70 10 10 0.2 > 21 days 19 70 10 10 0 creamed CT 70 10 0 0.4 U - STPP : Sodium tripolyphosphate PEG 200 : Polyethylene glycol molecular weight 200 Comparative test U :Unstable U : lUnstable Examples 20-21 Sodium tripolyphosphate (10 grams) was added to the composition prepared in Examples 17 and 1 8 after 2 days and the mixtures were homogenised in a high shear mixer. Stable compositions were obtained which were unchanged by three cycles between O"C and 40"C.

Example 22 A saturated aqueous solution (70 grams) of sodium tripolyphosphate containing 0.1 % w/w of a xanthan gum, was mixed with a 1:3 by weight mixture (10 grams) of "Synperonics" A3 and K87, polyethylene glycol molecular weight 200 (10 grams), Sodium sodium tripolyphosphate (10 grams), sodium carboxymethyl cellulose (0.2 grams; "Courlose" A610 ex Courtaulds), an optical brightener (0.2 grams; "Tinopal" CBS-X Ciba Geigy), a blue pigment (0.01 grams ; "Monastral" Blue ex ICI), a polysiloxane antifoam (0.01 grams). A stable composition with improved pour point was obtained.

Example 23 Solid particles of sodium tripolyphosphate (10 grams) were dispersed in a mixture of polyethylene glycol molecular weight 200 (10 grams) and a 1:2 by weight mixture (10 grams) of "Synperonic" A3 and "Synperonic" A7. The dispersion, sodium carboxylmethyl cellulose (0.5 grams), an optical brightener (0.2 grams), a blue pigment (0.02 grams; "Ultramarine" Blue ex Reckitt and Coleman), a polysiloxane antifoam (0.1 gram), a proteolytic enzyme (0.5 grams, "Esperase" 4T ex Novo) and a perfume (0.1 gram) were mixed with a saturated aqueous solution (70 grams) of sodium tripolyphosphate containing 0.2% w/w of a xanthan gum and homogenised using a "Silverson" mixer. A homogeneous mobile liquid was obtained which was stable at 4"C, 25"C and 40"C.

Detergency testing on this formulation at 60"C using a "Tergotometer" at 100 r.p.m. gave the results shown in Table 3. Results from comparative tests using a commercially available built anionic laundry liquid are also shown in Table 3. From the Table it can be seen that good results were obtained on cotton and polyester cotton for synthetic sebum.

TABLE 3

Water Increase in Reflectance Fabric Soil Hardness of Test Clothes (ppm CaC03) Example Comparative No. 23 Test (5 grams/litre) (5 grams/litre) C K 50 23.5 24.9 C K 300 22.7 23.8 PC K 50 20.2 16.6 PC K 300 17.6 9.9 C E116 50 35.6 40.2 C E116 300 18.7 42.1 C Elll 50 12.6 19.7 C Elll 300 1 4.6 1 14.9 C: Cotton PC: Polyester/cotton K: Synthetic sebum (Krefeld soil) E116: Blood, Milk Indian Ink mix (Empa 116) Ell: Blood soil (Empa 111).

Example 24 A 'Silverson' high shear mixer was used to mix a saturated solution (700 grams) of sodium tripolyphosphate containing 0.2% of a xanthan gum and 1 % of a montmorillonite clay ('Veegum' ex RT Vanderbilt Company, Inc. of Connecticut, USA) with a 1:2 by weight mixture (100 grams) of 'Synperonics' A3 and A7, polyethylene glycol molecular weight 200 (100 grams), sodium tripolyphosphate (100 grams), sodium carboxymethyl cellulose (5 grams), an optical brightener (2 grams, 'Tinopal' CBS-X) and a polysiloxane antifoam (1 gram; 'Silcolapse' 5008). A stable composition was obtained.

Claims

1. Aqueous liquid detergent composition in the form of an emulsion which comprises (a) droplets of a non-ionic surfactant which comprises one or more alkoxylated alkylphenols and/or alkoxylated alkanols; (b) a continuous phase which comprises an aqueous solution of one or more detergent builders; and (c) where the non-ionic surfactant consists of an alkoxylated alkanol, a low molecular weight polyethylene oxide.

2. A composition as claimed in claim 1 wherein the alkoxylated alkylphenol is derived from an octyl- and/or a nonylphenol.

3. A composition as claimed in claim 1 wherein the alkoxylated alkanol is derived from an alkanol having between 10 and 1 6 carbon atoms.

4. A composition as claimed in claim 1 wherein the alkoxyl group, in the alkoxylated alkylphenol or alkoxylated alkanol comprises a chain of between 4 and 1 5 ethoxyl groups.

5. A composition as claimed in claim 1 wherein the non-ionic surfactant provides between 5 and 50% w/w of the composition.

6. A composition as claimed in claim 1 wherein the concentration of the aqueous solution is less than 30% w/w.

7. A composition as claimed in claim 1 wherein the detergent builder is a phosphate.

8. A composition as claimed in claim 1 wherein the low molecular weight polyethylene oxide, where present, has a number average molecular weight between 100 and 800.

9. A composition as claimed in claim 1 wherein the low molecular weight polyethylene oxide, where present, provides up to 20% w/w of the composition.

10. A composition as claimed in claim 1 wherein the concentration of the one or more detergent builders, (a) is such that at least a portion thereof is dispersed or suspended in the emulsion in particulate form, and (b) provides up to about 30% w/w of the composition.

11. A composition as claimed in claim 10 wherein the size of the particles is less than 200 microns.

1 2. A composition as claimed in claim 1 containing an anti-creaming agent.

1 3. A composition as claimed in claim 1 2 wherein the anti-creaming agent is a dextran, a polyvinyl alcohol or a xanthan gum.

14. A process for preparing an aqueous liquid detergent composition as claimed in claim 1 with comprising a coarse mixing step and a homogenisation step.