NZ205345A - Aqueous,built liquid detergent compositions - Google Patents

Abstract

Aqueous, built liquid detergent compositions comprising an alkylaryl sulphonate and an alkylether sulphate as the detergent materials, and a phosphate builder show an irreversible increase in viscosity when subjected to high shearing action. The inclusion in such compositions of a certain level of a nonionic detergent surfactant according to the present invention enables the use of high shearing action, necessary to achieve the required physical stability, without an irreversible increase of the viscosity.

Description

New Zealand Paient Spedficaiion for Paient Number £05345 2053 << Priority Date{ s(s): 37-?."?.* Complete Specification Filed: . 22-3-33 Class: C.U.P.iJ.SS.

Publication Date: ....3 jQ.AUG.iaS5 P.O. Journal, No: ., IX11* EW ZEALAND PATENTS ACT, 1953 No.: Date: COMPLETE SPECIFICATION LIQUID DETERGENT COMPOSITION i /We, UNILEVER PLC, a Company organised under the laws of Great Britain, of Unilever House, Blackfriars, London, EC4, England hereby declare the invention for which &c/ we pray that a patent may be granted to and the method by which it is to be performed, to be particularly described in and by the following statement: - - 1 - (followed by page la) C 813 (R) 0 LIQUID DETERGENT COMPOSITION The present invention relates to an aqueous, built liquid detergent composition which is pourable, physically stable and has a satisfactory, reversible viscosity behaviour.

Aqueous, built liquid detergent compositions are well-known in the art. A vast amount of different formulations has been described in the prior art, but basically such formulations always contain one or more detergent 10 active compounds and one or more builder salts in an aqueous medium, and they are either true solutions, or suspensions, emulsions and the like, depending upon the type and amount of ingredients used.

The present invention is concerned with aqueous, built liquid detergent compositions of the suspension type, by which is to be understood that one or more of the ingredients of the detergent composition are suspended in the final composition.

Such types of aqueous, built liquid detergent compositi-ions have been described in the prior art. Thus, our British patent specification 855 893 describes aqueous built liquid detergent compositions in the form of pour-25 able suspensions, emulsions or coacervates which comprise as essential ingredients an alkylethersulphate, an alkylarylsulphonate, a carboxymethyl cellulose and an al-kalimetal condensed phosphate. A similar type of products is described in "New Zealand Patent Specification No 191283, 30 which contain an alkylethersulphate, preferably together with an alkylarylsulphonate, a builder salt such as an alkalimetal condensed phosphate, and an optical brightening agent.

C 813 (R) 20534-(? Aqueous, built liquid detergent compositions of the above type, which contain a mixture of an alkylethersulphate and an alkylarylsulphonate as the active detergent material, and an alkalimetal condensed phosphate as the 5 builder material, suffer however from the drawback that when they are subjected to high shearing action, e.g. during their manufacture when they are e.g. pumped or bottled, their viscosity is irreversibly increased to a very significant degree, resulting in products with an 10 unacceptably high viscosity. Some shearing action is however required to achieve the required physical stability of the products, since too low a shearing action may result in physically unstable products.

Consequently, if the manufacturer requires a product with an acceptable pourability and viscosity, he is compelled to use a medium or low shear action during manufacture, accepting a possible unsatisfactory physical stability. The control of this shear action while pumping or bottling 20 the liquid product is, moreover, difficult. Thus, in the above British patent specification 885 893 the products are prepared by homogenisation in a colloid mill, whereby they are subjected to high shear action, resulting in physically stable, but too viscous products, and products 25 prepared according to New Zealand Patent Specification No 1912 83, using controlled agitation (medium and strong, avoiding aeration), result in products with an acceptable physical stability, but unsatisfactory viscosity. Storage of the latter products at temperature cycling storage conditions 30 often results in an increased, irreversible viscosity.

It has now been found that these drawbacks can be overcome to a significant degree, if in the formulation also a certain amount of a nonionic detergent active material 35 is included. The presence of this material enables the use of high shearing action, after which however the vis- C 813 (R) 2 0 5345 cosity reversibly returns to an acceptable level, while maintaining the physical stability achieved by the high shear action.

In its broadest aspects therefore the present invention relates to an improvement in and to aqueous, built liquid detergent compositions which contain as essential ingredients an alkylethersulphate and an alkylarylsulphonate as the active detergent materials, and a builder 10 salt, the improvement comprising the inclusion in the composition of a certain level of a nonionic detergent active material.

Further aspects of the invention will become readily 15 apparent from the description of the invention and its various embodiments as detailed below.

The active detergent material comprises as essential ingredients an alkylethersulphate and an alkylarylsul-20 phonate.

The alkylethersulphates are represented by the following formula R<ocnH2n>moso3M in which R is a linear or branched alkyl chain having from 8 to 18 carbon atoms, n is 2 or 3, m is a number ranging from 1 to 10 and M is an alkalimetal, alkaline earth metal, ammonium or substituted ammonium radical.

R is preferably a linear Ci2~c15 alkyl chain, n is preferably 2, m is preferably from 2 to 5 and M is preferably sodium.

C 813 (R) 2 0 534 Typical examples of such alkylethersulphates are lauryl-ethersulphates containing from 2.5 to 3 moles of ethylene oxide or propylene oxide or a mixture of the two; sec. alkylethersulphates containing from 3 to 12 moles of 5 ethylene oxide and Ci2~^15 prim, alkylethersulphates containing 3 moles of ethylene oxide, all in the form of their sodium or potassium salts.

These alkylethersulphates are normally prepared by sul-10 phation of the corresponding alkoxylated alcohols; since the latter may contain a small amount of non-alkoxylated alcohol which on sulphation is converted into an alkyl-sulphate, it is to be understood that the term alkylethersulphate includes the product obtained by sulphation 15 of the corresponding alkoxylated alcohols.

The amount of alkylethersulphate, calculated as the sodium salt, required in the composition ranges from 0.2 to 7.5%, preferably from 0.5 to 5%, and particularly pre-20 ferably from 0.5 to 3.5% by weight of the final composition.

The alkylarylsulphonates are represented by the following formula 25 R SO3M in which R is a cio~C18 branclied or straight chain alkyl chain and M is as hereinbefore defined for the alkylethersulphates.

Typical examples of the alkylarylsulphonates are n-dode-cylbenzene sulphonate, tetrapropylenebenzene sulphonate, n-pentadecylbenzene sulphonate, and linear al_ kylbenzene sulphonate in which the Ci2~C15 alkylgroup is 35 obtained from cracked wax polymers, all in the form of their sodium or potassium salts.

C 813 (R) 2 053 Both the alkylethersulphates and the alkylarylsulphonates are well-known anionic synthetic detergents, amply described in the prior art, e.g. in the textbook of Schwartz Perry "Surface-active Agents and Detergents", Volumes I 5 and II of 1949 and 1958.

The alkylarylsulphonate is used in the present invention in an amount of 5-15, preferably 6-12% by weight of the final composition, the alkylarylsulphonate being calcu-10 lated as the sodium salt.

The builder which is used in the composition can be any conventional organic or inorganic builder. Typical examples thereof are the alkalimetal-ortho-, -pyro- and -tri-15 polyphosphates, -glassy polymeric phosphates, -citrates, -nitrilotriacetates, -carboxymethyloxysuccinates; zeolites, alkalimetal salts of aminopolyphosphonic acids and so on. Mixtures of various builders are also suitable.

The preferred builders are the alkalimetal phosphates such as sodium or potassium ortho-, -pyro- and -tripo-lyphosphate, sodiumtripolyphosphate being especially preferred. The amount of the builder present in the com-25 position ranges from 5 to 30% by weight of the final composition, preferably from 10-25% by weight.

The nonionic detergent which is included in the composition can be any well-known nonionic detergent. Nonionic 30 detergents usually consist of a hydrophobic moiety which has been reacted with an alkyleneoxide.

Typical examples are primary or secondary, straight- or branched-chain Cg-C^g alcohols, condensed with 1-30 35 moles of alkyleneoxide; mono- or dialkylphenols with an alkyl group of 9-18 carbon atoms, condensed with 1-30 C 813 (R) 205345 moles of alkyleneoxide; C;lo~c18 fatty acids or C^q-C^0 fatty acid mono- or -dialkylolamides condensed with 1-30 moles of alkyleneoxide; block copolymers of different or identical alkyleneoxides and so on. Usually the alkyl-5 eneoxide is ethyleneoxide, but propyleneoxide or mixtures of ethyleneoxide and propyleneoxide can also be used.

Further suitable examples can be found in the textbook of M. Schick "Nonionic Surfactants".

The amount of nonionic to be included in the composition ranges from 0.2-5, preferably from 0.5-3% by weight of the final composition.

The weight ratio of the total amount of anionic detergent 15 to the amount of nonionic varies from 2.5 to 1 to 25 to 1, preferably from 4:1 to 20:1.

The composition of the invention may advantageously further include a buffering agent in an amount of up to 20 10% by weight of the final composition. Suitable buffering agents are the alkanolamines, such as triethanol-amine, buffer salts such as the alkalimetal carbonates, alkalimetal borates, alkalimetal silicates and so on. It is one of the further advantages of the present inven-25 tion that the liquid compositions can tolerate appreciable electrolyte levels and that consequently further useful ingredients can be included without impairing the viscosity or stability of the formulations.

Thus, for example, alkalimetal sulphites can be included which improve the detergency; also enzymes, either alone or in admixture with enzyme stabilisers such as polyal-cohols or alkanolamines with borax, can be included.

Other ingredients, commonly used in liquid detergent 35 compositions, can also be included, such as soil-suspending agents, anti-redeposition agents, hydrotropes, corrosion inhibitors, foam boosters or foam depressors, C 813 (R) 205"3^S* 7 opacifying agents, perfumes, colouring agents, bleaching agents, bleach precursors, fluorescers and the like.

In this respect it is another advantage of the present 5 invention that any type of fluorescer can be included, also those which according to the above New Zealand Patent Specification No 191283 would not be suitable for inclusion in formulations according to that prior proposal.

The products of the present invention can be prepared using conventional techniques. It has in this respect been found that it is advantageous to shear the product at the end of its production process to its maximum stable viscosity, e.g. by post-stirring or passing the 15 product through a desintegrator or similar high shear exerting equipment. Further shear exerted on the thus treated product during its pumping or bottling does not affect the viscosity of the product further.

The invention will now further be illustrated by Way of Example.

Example 1 The following formulation was prepared: Sodium dodecylbenzene sulphonate Sodium laurylether sulphate (containing 2.5-3 moles of ethylene oxide) Lauryl alcohol, condensed with 8 moles of % (w/w) 10.0 0.5 ethylene oxide Sodium tripolyphosphate Sodium carbonate Fluorescer (a bis[o-sulphostyryl]biphenyl) Perfume 2.5 15.0 2.5 0.2 0.25 0.008 Dye Water to 100 C 813 (R) 20534 This product was prepared in the following way: To a slurry, containing water equivalent to 52% by weight of the above formulation, 0.008% dye, 0.1% sodiumdodecyl 5 benzenesulphonate, 0.2% fluorescer, 2.5% sodium carbonate and 15% sodium tripolyphosphate (partly in solution and partly present as hexahydrate crystals), 3.5 NaOH (34% aqueous solution) was added, followed by the addition of 10.0% dodecylbenzene sulphonic acid, subsequently 11.85% 10 water, thereafter 2.5% of the laurylalcohol, condensed with 8 moles of ethyleneoxide and finally the sodium laurylether sulphate. The last three ingredients were added as quickly as possible after each other under slow mixing conditions.

Immediately thereafter the product was deaerated, during which step the 0.25% perfume was added. Finally the whole product was agitated for 15-20 minutes while preventing aeration. The pH was adjusted to 10.5 + 0.25 by NaOH add-20 ition.

The product had a viscosity of 340 mPa.s (measured with a Haake Rotoviscometer at 25°C and 80 sec-*) and a spe-—- cific gravity of 1.15.

This product was stable for more than 3 months on storage at 0°C, 22°C and 37°C, respectively, and for more than 1 month at 52°C.

Example 2 In the same way as in Example 1 formulations were prepared from the same ingredients, but with varying amounts of the alkylarylsulphonate (LAS), the alkylethersulphate (LES) and the nonionic (Nl) detergent. The viscosity of 35 each of these formulations was assessed as in Example 1. The following results were obtained: C 813 (R) 205345" Formulation % (w/w) LAS LES NI Viscosity range Stability after 3 months' storage (mPa.s) at 0° 0 CM CM 37 "C A 11.0 1.0 1.0 430 + + + B 11.0 1.5 0.5 500 + + + C 11.0 2.0 0.0 330 -.

- + D .5 2.0 0.5 420 + + + E id.o 2.0 1.0 540 + + + F 9.5 3.0 0.5 520 + + + 6 9. 5 2. 5 1.0 520 + + + H 9.0 3.5 0.5 430 + + + I 8.5 2.0 2.5 360 + + + J 8.5 4.0 0.5 470 + + + K 8.0 4. 5 0. 5 530 + + + L 8.0 .0 0.0 470 - - + M 7.5 3. 5 2.0 380 + + + N 7.0 4.5 1.5 440 + + + Example 3 For comparison purposes, a formulation according to Example 1 of New Zealand Patent Specification No 19128 3 was prepared and then subjected to varying shear rates.

The formulation of Example 1 of the present application 25 was also subjected to these varying shear rates, and of both formulations the viscosities were assessed. The following results were obtained: With the prior art formulation the viscosity decreased 30 with an increasing shear rate (from about 3.0 Pa.s at a shear rate of 1 sec""* to about 300 mPa.s at 80 sec""*); if the viscosity of the same sample was then measured back when reducing the shear from high to low shear rates the viscosity was found to be much higher (from more than 35 10.0 Pa.s at 1 see"* to about 800 mPa.s at 80 sec~^L C 813 (R) 205345 Thus, after the product had been subjected to an increasing shear action, the viscosity increased to a much higher level when thereafter again a decreasing shear action was applied.

With the product of Example 1 of the present invention there was no difference in viscosity at increased and decreased shear rates; at 80 sec"^ it was about 320 mPa.s in both cases and at 1 sec-* about 12.0 Pa.s in both instances.

In the same way as in Example 1, using the same ingredients, a product was prepared but with 7% of sodium dodecylbenzene sulphonate, 5.5% sodium laurylethersul-phate, 0.5% nonionic detergent, 20% sodium tripolyphos-phate, 3.5% sodium carbonate and 0.15% of a fluorescer, known under the registered trade name of Blankophor RKH 766.

The viscosity of this product was 430 mPa.s (measured as in Example 1) and it was stable for more than 3 months on storage at 22°C and 3 7°C.

Example 4 Example 5 The following product was prepared: Sodium dodecylbenzene sulphonate Cl2~c13 primary linear alcohol condensed with 6.5 moles of ethylene oxide % by weight 6.0 2.2 Sodium laurylether sulphate Trisodium nitrilotriacetate 1 aq.

Borax Glycerol Water 6.6 12.0 5.0 7.0 q. s

Claims (6)

C 813 (R) 11 E? V ■■ ^ w W J The viscosity was measured at room temperature at a shear rate of 21 sec-*, with the following results:;10;15;20;storage time fresh 1 day 1 week 1 month 3 months;The following product viscosity (in Pa.s);1.05;1.0;1.05;1.0;1.05;Example 6;25;% by weight;Sodium dodecylbenzene sulphonate 8.2 Lauryl alcohol, condensed with;8 moles of ethylene oxide 2.5;Sodium laurylether sulphate 0.5;Borax 4.0;Glycerol 6.0;Tetra sodium pyrophosphate 11.0;Fluorescer 0.1;Proteolytic enzyme 0.4;Water q.s.;had a viscosity (at 23°C and 80 sec-*) of 300 mPa.s. The specific gravity was 1.15, the pH was 8.1. C 813 (R) r 12 345 WHAT^WE CLAIM IS: CLAIM3

1. An aqueous, built liquid detergent composition comprising, in an aqueous medium a) from 0.2 to 7.5% by weight of an alkalimetal alkylether sulphate detergent surfactant; 5 b) from 5 to 15% by weight of an alkalimetal alkylaryl sulphonate detergent surfactant; c) from 5 to 30% by weight of an organic or inorganic builder material; d) from 0.2 to 5% by weight of a nonionic detergent 10 surfactant.

2. The composition of claim 1, comprising from 0.5 to 3.5% of a), from 6 to 12% of b), from 10 to 25% of c) and from 0.5 to 3% of d). 15

3. The composition of claim 1, in which a) is a sodium alkylether sulphate in which the alkylgroup ranges from C12 to and the ethergroup consists of 2.5 to 3 moles of ethylene oxide, propylene oxide or a mixture 20 thereof, b) is sodium dodecylbenzene sulphonate, c) is selected from the group consisting of the alkalimetal orthophosphates, -pyrophosphates, -tripolyphosphates, -glassy polymeric phosphates, -citrates, -nitrilotriacetates,-carboxymethyl oxysuccinates, 25 -aminopolyphosphonates, and zeolites, and d) is an alkoxylated aliphatic Cg to C^g alcohol, condensed with 1 to 30 moles of ethylene oxide, propylene oxide or mixtures thereof. 30

4. The composition of claim 1, in which the nonionic detergent surfactant is a C12 to primary alcohol, condensed with 6.5 to 8 moles of ethylene oxide.

5. The composition of claim 1, in which the builder 35 material is selected from the group consisting of C 813 (R) 2 0 5345 sodium tripolyphosphate, tetrasodium pyrophosphate, trisodium citrate and trisodium nitriloacetate.

6. The composition of claim 1, in which the weight ratio of the sum of a) and b) to d) ranges from 2.5:1 to 25:1. DATED THIS ^"^DAY OF A. J. PARK & SON PER AGENTS FOR THE APPLICANTS