GB2188058A - Liquid hand cleaner containing solid phase - Google Patents

Abstract

A hand cleaning composition comprises solid particles dispersed in a pseudoplastic phase which remains in a gel-like state when subjected only to the weight of the particles, and comprising: an anionic surfactant, a non-ionic surfactant having a hydrophile-lipophile balance of 10 to 15, a third surfactant having a hydrophile-lipophile balance of 6 to 10, and a solvent, which may be a hydrocarbon. d p

Description

SPECIFICATION Liquid hand cleaner containing solid phase This invention relates to a cleaning composition suitable for cleaning heavily soiled hands.

Compositions for cleaning heavily soiled hands generally incorporate particles of a solid phase which serve as an abrasive. It is important that these particles are maintained in suspension in the composition. Gel-like compositions are known but these are relatively uneconomical to use, particularly if provided in drums or tubs since a handful of gel may be more than is required.

Gel-like compositions containing a solid phase cannot be easily dispensed.

Percentages referred to in this specification are by weight.

According to the present invention a cleaning composition comprises solid particles dispersed in a pseudoplastic phase, the pseudoplastic phase remaining in a gel-like state when subjected only to the weight of said particles, the pseudoplastic phase comprising: an anionic surfactant, a non-ionic surfactant having a hydrophile-lipophile balance of 10 to 15, a third surfactant having a hydrophile-lipophile balance of 6 to 10, and a solvent.

Each of the surfactants may comprise a single compound or a mixture.

Suitable anionic surfactants include: alkali or organic base salts of C,2 to C,8 straight or branched chain alkyl benzene sulphonic acids; C8 to C12 branched or straight chain alkyl sulphates; C8 to C,2 branched or straight chain alkyl sulphates which have been ethoxylated with 1-4 moles ethylene oxide; or fatty acid salts with ten to eighteen carbon atoms. The amount of aonionic surfactant may vary between 0.5 and 20.0 per cent, preferably between 8 and 14 per cent by weight of the final composition.

It is preferred to include said nonionic compound in the aqueous medium in an amount of from 2 to 14 per cent preferably from 6 to 10 per cent by weight. Suitable examples of nonionic detergents are water soluble condensation products of ethylene and/or propylene oxide with linear primary or secondary alcohols. Suitable alcohols are straight chain having ten to sixteen carbon atoms, preferably thirteen to fifteen carbon atoms with 1 to 9 moles of alkoxylation, preferably 5 to 8 moles of alkoxylation.

Preferred said non-ionic surfactants have a hydrophile-lipophile balance (HLB) of 11 to 13.

The third surfactant is preferably a non-ionic condensation product of ethylene and/or propylene oxide with a linear primary or secondary alcohol having an HLB of 6 to 10, more preferably 7 to 9. Preferred alcohols are primary alcohols having 10 to 16 carbon atoms, more preferably 12 to 15 carbon atoms. These may be accompanied by smaller amounts of 2-methyl derivatives. These third surfactants may incorporate 0 to 7 moles of ethylene and/or propylene oxide, preferably 1 to 4. Alternative surfactants include betains and amine oxides having similar HLB values.

The blend of anionic and two nonionic surfactants provides an HLB value which is suitable for emulsifying a hydrocarbon spirit. The emulsified spirit then modifies the HLB of the system to a value suitable for solubilising a variety of oils and greases.

The above alcohol ethoxylates and the hydrocarbons may be substituted by condensates of ethylene and/or propylene oxide with an alkyl phenol having similar HLB values.

A preferred solvent is an emulsified hydrocarbon having ten to eighteen carbon atoms in the liquid medium. Preferred examples are white spirit and deodourised kerosene. Levels may range from 1 to 15 per cent but levels of 2 to 6 per cent by weight are preferred. Such mineral oils would have an HLB in the range 1 to 4.

With suitable mixtures of the above materials structured liquids can be obtained. They are typified by their ability to retain air bubbles in indefinite suspension this being usually indicative that they will suspend particulate matter. Exclusion of the anionic surfactant, either the nonionic surfactants or the said third surfactant or the hydrocarbon from the formulation results in destructuring. This exhibits itself as lack of air bubble retention even for very brief periods of several seconds and a reduction in viscosity, particularly at very low shear stresses.

Surfactant molecules can exist in solution in four different ways e.g. at very low concentrations as single molecules, as spherical micelles having a fatty core with the water loving heads at the surface of the sphere, rod micelles and lamellar micelles.

It is believed that it is extended bilayers of surfactants and water layers that create systems having yield points and shear thinning properties. However, production of stable suspending liquids that are not too viscious is difficult to achieve. This invention relates to the use of water insoluble or miscible materials with water soluble materials to create an aqueous based suspending medium.

Addition of electrolyte to a detergent system can cause a change in micellar form e.g. from rods to lamellar. Whether this is due to the volume of the water phase being reduced thereby, in effect, concentrating the detergent system or partial salting out of active materials or a change in boundary layer counter ions is uncertain. Response of different systems to different electrolytes is variable; some electrolytes may have a stabilising effect on a system whilst others may cause phase separation.

In the absence of electrolyte the type and stability of a system wil be dependent upon the concentration of the active materials and the consequent inter and intra micellar interactions. As concentration increases the tendency will be to form lamellar micelles as this will reduce intermicellar repulsions. Having formed lamellar micelles it will then be intra-micellar replusions which influence stability. Since repulsions between tail groups will be low it will be repulsion forces between head groups that will have most influence on micelle stability. This assumes there to be no steric hinderance from large bulky, branched chains.

Based on these inter and intra-micellar interactions the invention relates to use of particular active materials at concentrations and ratios that encourage stable suspending liquid media to be produced. In particular, the blend is also constituted of active materials suited for the purpose intended, that is removal of grime and grease from hands.

Of the materials selected, those preferred have straight chains, particularly of thirteen ot fifteen carbon atoms. The solvents most appropriate have chain lengths also of this order i.e. twelve to sixteen carbon atoms and are preferably straight chain hydrocarbons. To reduce head-head repulsions between the anionic detergent and the alcohol (or phenol) ethoxylate of 5 to 7 moles ethylene oxide, an insoluble alcohol ethoxylate averaging only 1-4 moles ethylene oxide and a hydrocarbon (i.e. tail only) are preferably included in the formulation. Their inclusion in the system is believed to increase the intermolecular distance between the surfactants of large head group size thereby reducing head-head repulsions which might otherwise lead to destabilisation and phase separation.

Preferred amine oxides have two short alkyl chains (one to four carbon atoms) and one iong alkyl chain (eight to eighteen carbon atoms). Partial or full replacement of one of the nonionic detergents may be achieved using an amine oxide in which the long chain has a preferred length of fourteen to sixteen carbon atoms.

Betaines can also be included in the product but those having an N-alkyl group of fourteen to eighteen carbon atoms are preferred for use as viscosity modifiers in the present invention.

It is desirable to have the solid phase distributed throughout the liquid medium. Suitable materials may be of natural or synthetic origin, for example: calcite, dolomite, arogonite, feldspar, alumina, silica abrasives, polyethylene, polypropylene, polycarbonate, polystyrene, or any other plastic materials which is available in beaded shredded or granulated form. The particles may be used at levels of 0.5 to 8 per cent but preferably 1.5 to 4.5 per cent by weight. A particle size of from 50 to 600 micrometres may be used but preferably from 100 to 400 micrometres with the mean size anywhere within that range.

An electrolyte or mixture of elecrolytes may be required such as alkali metal chlorides, nitrates, borates, carbonates, bicarbonates, sulphates, orthophosphates, pyrophosphates, polyphosphates, citrates, nitrilotriacetates, ethylenediaminetetra-acetates. The electrolyte may range from 0.2 to 10 per cent, preferably 0.5 to 3 per cent by weight.

Other adjuncts to the liquid medium may be included such as colouring agents, perfumes, flourescers, hydrotropes, soil suspending agents, opacificers, germicides, humectants, skin conditioners, preservatives etc.

The invention will further be described by way of example but not in any limitative sense.

1. Influence of materials on structure and viscosity That each of the components in the liquid medium is essential is illustrated by the results obtained with the following five formulations: Formulation (%) Material Al A2 A3 A4 A5 Water 75 80 80 78 88 Alkyl benzene sulphonate 12 12 12 12 0 Alcohol ethoxylate 7EO 5 0 5 5 5 Alcohol ethoxylate 3EO 3 3 3 0 3 White Spirit 5 5 0 5 5 See Table 1 and Fig. 1 for viscosity results.

Formula Al was considerably viscous and exhibited excellent bubble retention and has shown prolonged storage stability.

Formula A2 had a very low viscosity over the wide range of shear rates over which evaiuated and showed no bubble retention. The formula would not retain all of its alcohol ethoxylate in solution.

Formula A3 was moderately viscous but did not retain air bubbles in suspension. Also phase separation occurred within hours.

Formula A4 was very low in viscosity, did not retain air bubbles in suspension but was stable.

Formula A5 was very low in viscosity, did not retain air bubbles in suspension but was stable.

Thus, exclusion of any of the water insoluble materials results in either loss of structure or instability i.e. phase separation.

2. Influence of electrolyte (sodium chloride) on rheology Formulation (%) Material 2A 2B 2C 2D 2E 2F Water 72.5 71.5 70.5 69.5 68.5 67.5 Sulphonic acid (95%) 11.5 11.5 11.5 11.5 11.5 11.5 White spirit 5.0 5.0 5.0 5.0 5.0 5.0 NaOH liquor 47% 3.0 3.0 3.0 3.0 3.0 3.0 Alcohol ethoxylate 7EO 5.0 5.0 5.0 5.C 5.0 5.0 Alcohol ethoxylate 3EO 3.0 3.0 3.0 3.0 3.0 3.0 Sodium chloride -- 0.5 1.0 2.0 3.0 4.0 Formula 2A was unstructured and of low viscosity whereas 2B, 2C, 2D and 2E were structured with viscosity increasing with salt content. Formula 2F showed phase separation.

Replacement of sulphonic acid and caustic soda with alkyl benzene sulphonate powder of about 95% activity dispensed with the need to add extra electrolyte. This may be due to the presence of sodium chloride resulting from bleaching of neutralised sulphonate liquor prior to drying. Varying levels of sulphate in the sulphonic acids used or the sulphonates used may require adjustment of the electrolyte content accordingly.

3. Formulations based on nonionic surfactants Formulation (%) Material 3A 3B 3C 3D 3E 3F 3G 3H Water 79 70 80 62 82 75 86 82 Alcohol ethoxylate 7EO 14 14 12 12 Alcohol ethoxylate 3ED 5 6 4 6 3 5 2 4 Nonyl phenol 8EO --- -- -- -- 12 12 13 10 White spirit 2 10 4 20 3 8 2 4 All of these products, although of variable viscosity and opacity were fairly mobile liquids capable of suspending a mineral. However, the products were not as pleasant to use as those containing some anionic detergent. Nevertheless, the cleaning effectiveness of all formulations was acceptable.

4. Effect of electrolyte on systems Formulation (%) Material 4A 4B 4C 4D 4E 4F 4G 4H 41 Water 80.5 80.5 80.5 74 74 74 69 69 69 Alcohol ethoxylate 7ED 9 9 9 6 6 6 12 12 12 Alcohol ethoxylate 3EO 2 2 2 3 3 3 4 4 4 Alkyl benzene sulphonate 5 5 5 12 12 12 8 8 8 White spirit 2 2 2 3 3 3 5 5 5 Sodium chloride 1.5 - - 2 - - 2 - Sesquicarbonate Na - 1.5 - - 2 - - 2 Sodium tripolyphosphate - - 1.5 - - 2 - - 2 In series 4A, 48 and 4C, sesquicarbonate assisted stability whereas sodium chloride and sodium tripolyphosphate had a destabilising effect. However, with series 4E to 41 sodium chloride had a stabilising influence but tripolyphosphate and sesquicarbonate caused destabilisation.

5. Influence of active ratios Formulation (%) Material 5A 5B 5C 5D; 5E 5F 5G 5H 51 5J Water 72 73 74 68 75 76 77 75 77 77 Alkyl benzene sulphonate 12 12 12 12 12 0 0 10 8 10 Alcohol ethoxylate 7EO 5 5 5 10 5 5 5 5 5 5 Alcohol ethoxylate 3EO 5 5 5 5 5 14 12 5 5 5 White spirit 0 5 4 5 3 5 6 5 5 3 Structure varied from slight in formula 5F to considerable in formula 5H, which was very viscous at ambient temperatures. Products 5F and 5G, although structured, were of very low viscosity.

6. Formulations with alternative solvents Formulation (%) Material 6A 6B 6C 6D 6E 6F Water 75 75 75 75 75 75 Alkyl benzene sulphonate 12 12 12 12 12 12 Alcohol ethoxylate 7Eo 5 5 5 5 5 5 Phenol ethoxylate 4EO 3 3 3 3 3 3 kerosene 5 - - - - Dioxitol (1) - 5 - - - - Material 6A 6B 6C 6D 6E 6F Rewopal MPG 10 (2) - - 5 - - - Rewopal MPG 40 (2) - - - 5 - PEG 200 - - - - 5 PEG 400 - - - - - 5 (1) Shell chemicals (2) Rewo chemicals Formulations 6A, 6C, 6D, 6E and 6F produced structured systems. Dioxitol formulations could be stabilised by addition of 2 to 4 per cent of kerosene or white spirit.

7. Formulations containing other actives Formulation (e) Material 7A 7B 7C 7D 7E 7F 7G 7H Water Alkyl benzene sulphonate 8 4 - - - - - - Lauryl sulphate 4 4 - - ^ 1.Alcohol ether (3EO) -. 4 12 8 4 - - 4 sulphate (70%) 'Amine Oxide (C14alkyl) - - - 4 10 - - )(30%) Amine Oxide (C16 alkyl) - - 4 - - 10 - (30%) Betain (C18) (30%) ) - - - - - 10 4 Alcohol ethoxylate 7EO - - 4 - - - - 2 Alcohol ethoxylate 3EO 3 3 3 3 3 3 3 3 White spirit - 5 5 5 5 5 5 5 5 (1) A 3 mole ethoxylate C13 15 alcohol supplied by Cafchem Limited.Trade Name Synperonic 3-S-70 (2) Dimethyl C,4 alkyl amine oxide supplied by Albright and Wilson. Trade Name Empigen OH.

(3) Dimethyl C16 alkyl amine oxide supplied by Akzo Chemie. Trade name Aromex DM 16 D.

(4) Experimental product manufactured by ABM Chemicals.

All the products showed excellent structuring properties. However, those containing amine oxides and betaines did not clean as effectively as the other formulations. Amine oxides and betaines of shorter chain lengths than those above could be partially substituted for the anionic (alkyl benzene sulphonate) without detriment to structuring.

Alternative materials 1. Anionic detergents Material Trade Name Manufacturer Alkyl benzene sulphonate AAS 90 Heinkel Chemicals Ltd Alkyl benzene sulphonic acid Sipex DS Heinkel Chemicals Ltd.

Alkyl benzene sulphonic acid Nausa 1042 Albright and Wilson.

Alkyl benzene sulphonic acid Caflon SA Cafchem Ltd.

Alkyl benzene sulphonic acid Caflon SNA Cafchem Ltd.

Alkyl benzene sulphonic acid Reworyl K Rewo Chemicals Ltd.

Lauryl sulphate Rewopal NLS 90 Rewo Chemicals Ltd.

Alcohol ether sulphate Empimen Albright and Wilson.

KSN 27 Sodium alkyl sulphonate Latensit B.A.S.F.

A - PS 2. Alcohol ethoxylates Trade Name Manufacturer Synperonic A2,A3,A4,A6,A7,A9 and All. Cafchem Limited Dobanol 25-3 and 25-9 Shell Chemicals Ltd.

Nonidet LE Shell Chemicals Ltd.

Lutensol A8,A03,A05,A07,A08 and A010. B.A.S.F.

Lutensol ON3D,0N50,0N60,0N70 and ON80. B.A.S.F.

Lutensol T04, TC5, TO8. B.A.S.F.

3. Alkyl Phenol ethoxylates Trade Name Manufacturer Synperonic NP4,NP6,NP8,NP9 and NP10. Cafchem Ltd.

Rewopal H V 5 Rewo Chemicals Ltd.

Lutensol AP 6, AP 7, AP 8, AP 9. B.A.S.F.

4. Amine oxides Type. Trade Name Manufacturer Dimethyl lauryl/myristyl. Empigen QB Albright & Wilson.

Dimethyl N-alkyl ethoxy Empigen 0Y Albright & Wilson.

Lauryl dimethyl Rewominox L408 Rewo Chemicals Ltd.

TABLE 1.

VISCOSITY (c.p.s.) Shear rate (cm-) Al A2 A3 A4 A5 4.7 5110 2190 6.4 3140 1570 8.8 2392 223 1299 61 36 10.3 184 54 34 11.8 2223 1235 13.0 1638 170 1180 45 32 16.5 - 136 47 34 20.0 1585 lOll 25.0 121 718 49 34 Shear rate (cm ) Al A2 A3 A4 AS 27.5 1178 810 37.5 80 740 51 33 44.0 60 50 33 48.0 952 63 680 53 32 50.7 1008 616 66.0 54 68.0 708 531 71.0 42 52 34 92.5 48 46 33 104.0 45 45 34 109.0 32 49 32 125.0 787 500 134 33 47 30 175 23 43 31 205 25 48 32 258 30 48 32

Claims (24)

1. A cleaning composition comprising solid particles dispersed in a pseudoplastic phase, the pseudoplastic phase remaining in a gel-like state when subjected only to the weight of said particles, the pseudoplastic phase comprising: an anionic surfactant, a non-ionic surfactant having a hydrophile-lipophile balance of 10 to 15, a third surfactant having a hydrophile-lipophile balance of 6 to 10, and a solvent.

2. A composition as claimed in claim 1, wherein the anionic surfactant is selected from the group comprising: alkali or organic base salts of C,2 to C18 straight or branched chain alkyl benzene sulphonic acids; C8 to C12 branched or straight chain alkyl sulphones; C8 to C,2 branched or straight chain alkyl sulphonates which have been ethoxylated with 1 to 4 moles of ethylene oxide; C10 to C18 fatty acid salts.

3. A composition as claimed in claim 1 or 2, comprising 0.5% to 20.0% of anionic surfactant.

4. A composition as claimed in claim 3, comprising 8% to 14% of anionic surfactant.

5. A composition as claimed in any preceding claim, comprising 2% to 14% of nonionic surfactant.

6. A composition as claimed in claim 5, comprising 6% to 10% of nonionic surfactant.

7. A composition as claimed in any preceding claim, wherein the nonionic surfactant is selected from the group comprising water soluble condensation products of ethylene and/or propylene oxide with linear primary or secondary alcohols.

8. A composition as claimed in claim 7, wherein the nonionic surfactant comprises a water soluble condensation product of a linear C10 to C16 alcohol with 1 to 9 moles of a ethylene and/or propylene oxide.

9. A composition as claimed in claim 8, wherein the nonionic surfactant comprises a water soluble condensation product of a linear C13 to Ca5 alcohol.

10. A composition as claimed in claim 8 or 9, wherein the nonionic surfactant comprises a water soluble condensation product including 5 to 8 moles of ethylene and/or propylene oxide.

11. A composition as claimed in any preceding claim, wherein the nonionic surfactant has a hydrophile-lipophile balance of 11 to 13.

12. A composition as claimed in any preceding claim, wherein said third surfactant is a nonionic condensation product of ethylene and/or propylene oxide with a linear primary or secondary alcohol having a hydrophile-lipophile balance of 6 to 10.

13. A composition as claimed in claim 12, wherein the third surfactant is a condensation product of a linear primary or secondary alcohol having a hydrophile-lipophile balance of 7 to 9.

14. A composition as claimed in claim 12 or 13, wherein the third surfactant is a condensation product of a C10 to C,6 primary alcohol.

15. A composition as claimed in claim 14 wherein the third surfactant is a condensation product of a C12 to C18 primary alcohol.

16. A composition as claimed in any preceding claim, wherein the solvent is a C10 to C18 hydrocarbon.

17. A composition as claimed in claim 16, comprising 1% to 15% of the solvent.

18. A composition as claimed in claim 17, comprising 2% to 6% of the solvent.

19. A composition as claimed in any preceding claim, comprising 0.5% to 8% of the solid particles.

20. A composition as claimed in claim 19, comprising 1.5% to 4.5% of the solid particles.

21. A composition as claimed in any preceding claim, wherein the solid particles have a particle size of 50 to 600 micrometers.

22. A composition as claimed in claim 21, wherein the particle size is 100 to 400 micrometers.

23. A composition as claimed in any preceding claim, including an electrolyte or mixture thereof.

24. A composition substantially as hereinbefore described.