EP0505371B1

EP0505371B1 - Liquid detergents

Info

Publication number: EP0505371B1
Application number: EP90916476A
Authority: EP
Inventors: Stephen Graham Hales; Ezat Khoshdel; Peter Graham Montague; Johannes Cornelis Van De Pas; Adrianus Visser; Cornelis Winkel; Ronald Peter Potman
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 1989-12-12
Filing date: 1990-11-14
Publication date: 1996-03-06
Anticipated expiration: 2010-11-14
Also published as: CA2070817A1; ES2084043T3; EP0505371A1; DE69025770D1; WO1991009109A1; DE69025770T2; GB8928067D0

Abstract

A liquid detergent composition comprising a dispersion of lamellar droplets in an aqueous continuous phase, said composition also comprising a biodegradable deflocculating polymer.

Description

The present invention relates to liquid detergent compositions, in particular to liquid detergent compositions which comprise a dispersion of lamellar droplets in an aqueous continuous phase.
Lamellar droplets are a particular class of surfactant structures which, inter alia, are already known from a variety of references, e.g. H.A.Barnes, 'Detergents', Ch.2. in K.Walters (Ed), 'Rheometry: Industrial Applications', J. Wiley & Sons, Letchworth 1980.
Such lamellar dispersions are used to endow properties such as consumer-preferred flow behaviour and/or turbid appearance. Many are also capable of suspending particulate solids such as detergency builders or abrasive particles. Examples of such structured liquids without suspended solids are given in US patent 4 244 840, whilst examples where solid particles are suspended are disclosed in specifications EP-A-160 342; EP-A-38 101; EP-A-140 452 and also in the aforementioned US 4 244 840. Others are disclosed in European Patent Specification EP-A-151 884, where the lamellar droplet are called 'spherulites'.
The presence of lamellar droplets in a liquid detergent product may be detected by means known to those skilled in the art, for example optical techniques, various rheometrical measurements. X-ray or neutron diffraction, and electron microscopy.
The droplets consist of an onion-like configuration of concentric bi-layers of surfactant molecules, between which is trapped water or electrolyte solution (aqueous phase). Systems in which such droplets are close-packed provide a very desirable combination of physical stability and solid-suspending properties with useful flow properties.
The viscosity and stability of the product depend on the volume fraction of the liquid which is occupied by the droplets. Generally speaking, when the volume fraction is around 0.6, the droplets are just touching (space-filling). This allows reasonable stability with an acceptable viscosity (say no more than 2.5 Pas, preferably no more than 1 Pas at a shear rate of 21s⁻¹). This volume fraction also endows useful solid-suspending properties.
A problem in formulating detergent compositions of high lamellar phase volume is a possible instability and/or high viscosity of the product. These problems are fully described in our co-pending European patent application 89201530.6 (EP 346 995).
A problem in formulating detergent compositions comprising polymeric ingredients, is that these compositions are sometimes less preferred for environmental reasons, because the polymeric ingredients are often less biodegradable.
We have now found that the dependency of stability and/or viscosity upon volume fraction can be favourably influenced and the above mentioned environmental side-effects of the polymers can be reduced, by incorporating into a lamellar detergent composition a biodegradable deflocculating polymer.
Accordingly the present invention relates to a liquid detergent composition comprising a dispersion of lamellar droplets in an aqueous continuous phase, said composition also comprising a biodegradable deflocculating polymer, selected from the four classes described below.

The deflocculating polymer

Suitable deflocculating polymer types for use in compositions of the present invention are for instance described in our copending European patent application 89201530.6 (EP 346 995) (published on 20 December 1989). and in our non-prepublished patent applications WO/91/06622 (published on 16 May 1991), WO/91/06623 (published on 16 May 1991) and GB 2,237,813 (published on 15 May 1991). Of the general classes of polymers as described in these patent documents, only the use of biodegradable polymers is embraced within the scope of the present invention. It is believed to be well within the ability of the skilled person to select on the basis of general knowledge on polymer degradability combined with the teaching as provided in the above mentioned non-prepublished patent applications those deflocculating polymers that will be suitable for use in compositions of the invention.
Suitable tests for determining biodegradability are given in the OECD Guidelines. Other suitable tests involve the detection of released CO₂ upon decomposition of the polymer material, in these tests sometimes ¹⁴C labelled polymers may be used. Although it is preferred that polymers for use in composition of the invention satisfy most or all of the available tests, applicants have found that polymers satisfying one or more biodegradability tests are suitable for use in the present invention.
Polymers for use in compositions of the invention must satisfy one or more of the following tests:

(a) Modified Sturm test as described in OECD Guideline 301b. This test measures CO₂ production from the test material under standard conditions. A 60 % conversion to CO₂ in the Sturm test is an indication of ready biodegradability. However, the results of this test are not fully reliable; biodegradable materials can fail this test.
(b) Modified SCAS test as described in OECD Guideline 302a. This test measures removal of test material by dissolved organic carbon analysis. It is believed that a 80 % removal is a reasonable indication of biodegradability or adsorption.
(c) Combined modified SCAS test and Sturm test. This test involves a modified SCAS test as described above, wherein the SCAS effluent is used as the inoculum in a modified Sturm test-system. A 60 % conversion to CO₂ in the Sturm system using the acclimatised SCAS inoculum is an indication of inherent biodegradability.
(d) Batch activated sludge test of ¹⁴C labelled polymers. This determines whether during 6 weeks incubation at ambient temperature ¹⁴CO₂ can be detected. Any detected ¹⁴CO₂ is a sign of biodegradability, the amount of detected ¹⁴CO₂ is a measure of the extent of biodegradability. For example an amount of detected ¹⁴CO₂ after 100 days corresponding to more than 20 wt % of the initial carbon-14 content of the test material is an indication of reasonable biodegradation, while more than 50 wt % would be an indication of very good biodegradation.
(e) Soil biodegradation tests of ¹⁴CO₂ labelled polymers. This test determines during 100 days incubation at ambient temperature, whether ¹⁴CO₂ can be detected from test material applied to soil. Any detected ¹⁴CO₂ is a sign of biodegradability, the amount of detected ¹⁴CO₂ is a measure of the extent of biodegradability. For example an amount of detected ¹⁴CO₂ corresponding to more than 40 or 50 wt % of the initial carbon content of the test material would be an indication of very good biodegradation.
(f) Anaerobic Batch test of ¹⁴C labelled polymers. This test determines whether radio labelled CH₄ or CO₂ can be detected upon incubation of a batch of material at ambient temperature for 28 days under anaerobic conditions. Any detected ¹⁴CO₂ or ¹⁴CH₄ is a sign of biodegradability, the amount of detected ¹⁴CO₂ or ¹⁴CH₄ is a measure of the extent of biodegradability. For example an amount of detected ¹⁴CO₂ or ¹⁴CH₄ corresponding to more than 40 or 50 wt % of the initial carbon-14 content of the test material would be an indication of very good biodegradation.
(g) Continuous activated sludge simulation tests. In this test material is continuously dosed. After an adaptation period of up to 2 months removal by biodegradation or adsorption is estimated by measuring the removal of test material by dissolved organic carbon analysis. It is believed that a 80 % removal is a reasonable indication of biodegradability or adsorption.
(h) continuous activated sludge simulation tests using radiolabelled polymers. In this test non-radiolabelled polymer is continuously dosed and radiolabelled polymer is only dosed after an adaptation period of up to 2 months. During the period of radiolabelled polymer dosing the amount of C-14 appearing in the effluent, on sludge solids and released as ¹⁴CO₂ is determined. It is believed that an 80 % removal of dosed C-14 is a reasonable indication of either biodegradability or adsorption. Any detected ¹⁴CO₂ is a sign of biodegradability. A yield corresponding to 10 % by weight of the initial level of radiocarbon demonstrates biodegradability, a yield of 40 % indicates very good biodegradability.

A preferred way of distinguishing between a non-preferred polymer and a preferred biodegradable polymer involves a combination of tests b) and c) mentioned above as follows: Preferred polymer materials provide more than 80 % removal in the Modified SCAS test and more than 60 % conversion in the Sturm test-system using a SCAS inoculum. Polymers which provide less than 80 % removal in the modified SCAS test are less preferred for use in compositions of the invention, while composition which provide more than 80 % removal in the SCAS test but less than 60 % conversion in the STURM test-system using a SCAS inoculum are moderately preferred for use in composition of the invention.
The first class of polymers for use in compositions of the invention are biodegradable polymers having a hydrophilic backbone and at least one hydrophobic side chain. The basic structure of polymers having a hydrophilic backbone and one or more hydrophobic side-chains is described in EP 89201530.6 (EP 346 995).
Generally the hydrophilic backbone of the polymer is predominantly linear (the main chain of the backbone constitutes at least 50 %, preferably more than 75 %, most preferred more than 90% by weight of the backbone), suitable monomer constituents of the hydrophilic backbone are for example unsaturated C₁₋₆ acids, ethers, alcohols, aldehydes, ketones or esters, sugar units, alkoxy units, maleic anhydride and saturated polyalcohols such as glycerol. Examples of suitable monomer units are acrylic acid, alpha hydroxy acrylic acid, alpha hydroxy methyl hydroxy acid, methacrylic acid, maleic acid, vinyl acetic acid, glucosides, ethylene oxide and glycerol. The hydrophilic backbone made from the backbone constituents in the absence of hydrophobic side-groups is relatively water-soluble at ambient temperature and a pH of between 6.5 and 14.0.
Preferably the solubility is more than 1 g/l, more preferred more than 5 g/l most preferred more than 10 g/l.
Preferably the hydrophobic sidegroups are composed of relatively hydrophobic alkoxy groups for example butylene oxide and/or propylene oxide and/or alkyl or alkenyl chains having from 5 to 24 carbon atoms. The hydrophobic groups may be connected to the hydrophilic backbone directly or via relatively hydrophilic linkages for example a poly ethoxy linkage.
Preferred polymers are of the formula:
z is 1, q is preferably at least 1, (q+x+y) : z is from 4 : 1 to 1,000 : 1, preferably from 6 : 1 to 250 : 1; in which the monomer units may be in random order; y preferably being from 0 up to the value of x; n is at least 1; q is preferably at least 1; x may be 0.

R¹ represents -CO-O-, -O-, -O-CO-, -CH₂-, -CO-NH- or is absent;
R represents from 1 to 50 independently selected alkyleneoxy groups preferably ethylene oxide or propylene oxide groups, or is absent, provided that when R³ is absent and R⁴ represents hydrogen or contains no more than 4 carbon atoms, then R must contain an alkyleneoxy group preferably more than 5 alkyleneoxy groups with at least 3 carbon atoms;
R³ represents a phenylene linkage, or is absent;
R⁴ represents hydrogen or a C₁₋₂₄ alkyl or C₂₋₂₄ alkenyl group, with the provision that when R is absent, R⁴ is not hydrogen and when also R³ is absent, then R⁴ must contain at least 5 carbon atoms;
R⁵ represents hydrogen or a group of formula -COOA⁴;
R⁶ represents hydrogen or C₁₋₄ alkyl; and
R¹ represents -H, -CO-CH₃, -CH₂-COOA⁴, -CO-CH₂-CH₂-COOA⁴,-CH₂-CH=CH-COOA⁴ -CO-CH-COOA⁴ or -CO-CH₂-CH=CHCOOA⁴

A¹, A, A³ and A⁴ are independently selected from hydrogen, alkali metals, alkaline earth metals, ammonium and amine bases and C₁₋₄, or (C₂H₄O)_tH wherein t is from 1-50, and wherein the monomer units may be in random order.
Each B¹ is independently selected from -CH₂OH, -OH or -H;
For each monomer unit R¹-R¹, A¹-A⁴ and B¹ may independently be selected from the groups mentioned above.
The second class of polymers for use in the present compositions are hydrophobically modified polysaccharides. Possible sugar units for use in those polymers include glucosides and fructosides for example maltoses, fructoses, lactoses, glucoses and galactoses. Also mixtures of sugar groups may be used. The sugar groups may be connected to each other via any suitable linkage, although 1-4 linkages and/or 1-6 linkages and/or 1-2 linkages are preferred. The polysaccharides are preferably predominantly linear, but also branched polymers may be used. Especially preferred is the use of hydrophobically modified dextrans, more preferably of dextrans having a molecular weight of 2,000 to 20,000. An example of a preferred polysaccharide has the following formula:
Wherein:

Each R^7' is R⁷ or -R¹-R-R³-R⁴;
R⁷ is independently selected from -OH, -NH-CO-CH₃, -SO₃A¹, -OsO₃A¹, -NHSO₃A¹, -COOA¹; R⁷ is preferably -OH
n is the total number of -R¹-R-R³-R⁴ groups per molecule; n is at least 1;
m is the total number of R⁷ and R^7' groups that are not -R¹-R-R³-R⁴;
the patio m : n is from 12 : 1 to 3,000 : 1, preferably from 18 : 1 to 750 : 1; wherein the monomer units may be in random order. v and w are determined by the molecular weight of the polymer.
R¹ is as defined above for formula I, or can be -NHCO-; -OCH₂CONH-; or -O-CH₂-CO-O-;
R⁻⁴ are as defined for formula I;
A¹ is as defined for formula I.

A second example of a preferred Hydrophobically modified polysugar is of the formula:
Wherein R⁷, R^7', R¹⁻⁴, A¹, v and w, m and n are as defined above.
It is believed that on the basis of these formulas, the skilled person will be able to derive similar formulas for other polysaccharide polymers for use in compositions of the invention.
The third class of polymers for use in the present compositions are of the formula:
Wherein:

z and n are as defined for formula I; (x+y) : z is from 4 : 1 to 1,000 : 1, preferably from 6 : 1 to 250 : 1; y preferably being from zero up to a maximum equal to the value of x; wherein the monomer units may be in random order.
R¹⁻⁶ are as defined for formula I;
R⁸ and R⁹ represent -CH₂- or are absent;
S¹ and S are independently selected from -CO(CH₂)₂COOA¹, -CO(CH)2COOA¹, -COCH₂C(OH) (COOA¹) CH₂COOA¹, -COCH₂COOA¹, -CO(CH(OH))₂COOA¹, -COCH₂CH(OH)COOA¹, -COCH₂CH(CH₃)COOA¹ and -COCH₂C(=CH₂)COOA¹, -H, -COCH₃;
A¹ is as defined for formula I;

The fourth class of polymers for use in the present compositions are of the formula:
Wherein:
D is -H or -OH; n is at least 1;
Wherein:

Each A is A¹ or R¹⁰;
Q¹ : Q is from 4 :1 to 1,000 : 1, preferably from 6 : 1 to 250 : 1;
R¹⁰ represents a C₅₋₂₄ alk(en)yl group;
B is ---O---CO---R¹¹---CO----
R¹¹ represents -CH₂-, -C₂H₄-, -C₃H₆-, or an aryl link said aryl link optionally being substituted with one or more -COOA¹ groups, or a benzophenone link;
A¹ is as defined for formula I.

Preferably polymers for use in compositions have a molecular weight (determined as in our co-pending patent application EP 346 995) of between 500 and 500,000. Polymers according to formulas II-IV preferably have a molecular weight of 500-250,000, more preferred from 1,000-100,000, most preferably from 2,000 to 50,000. Polymers according to formula I, preferably are low molecular weight polymers, preferably having a molecular weight of less than 50,000, more preferred less than 10,000, especially preferred less than 5,000, most preferably from 500 to 2,000. The polymers for use in detergent compositions of the invention may be prepared by using conventional polymerisation procedures, such as radical polymerisation or condensation polymerisation; suitable methods are for example described in the above mentioned co-pending European patent application.
Generally the deflocculating polymer will be used at from 0.01 to 5 % by weight of the composition, more preferably from 0.1 to 3.0, especially preferred from 0.25 to 2.0 %.
Without being bound by any particular interpretation or theory, the Applicants have hypothesised that the polymers exert their action on the composition by the following mechanism. The hydrophobic side-chain(s) or ionic groups could be incorporated in or onto the outer bi-layer of the droplets, leaving the hydrophilic or nonionic backbone over the outside of the droplets and/or the polymers could be incorporated deeper inside the droplet.
When the hydrophobic side chains or ionic groups are mainly incorporated in or onto the outer bilayer of the droplets, this has the effect of decoupling the interand intra-droplet forces i.e. the difference between the forces between individual surfactant molecules in adjacent layers within a particular droplet and those between surfactant molecules in adjacent droplets could become accentuated in that the forces between adjacent droplets are reduced. This will generally result in an increased stability due to less flocculation and a decrease in viscosity due to smaller forces between the droplets resulting in greater distances between adjacent droplets.
When the polymers are incorporated deeper inside the droplets also less flocculation will occur, resulting in an increase in stability. The influence of these polymers within the droplets on the viscosity is governed by two opposite effects : firstly the presence of deflocculating polymers will decrease the forces between adjacent droplets resulting in greater distances between the droplets, generally resulting in a lower viscosity of the system; secondly the forces between the layers within the droplets are equally reduced by the presence of the polymers in the droplet, this generally result in an increase in the layer thickness, therewith increasing the lamellar volume of the droplets, therewith increasing the viscosity. The net effect of these two opposite effects may result in either a decrease or an increase in the viscosity of the product.
The compositions according to the invention are physically stable and have a relatively low viscosity, i.e. a corresponding composition minus the deflocculating polymer is less stable and/or has a higher viscosity.
In the context of the present invention, physical stability for these systems can be defined in terms of the maximum separation compatible with most manufacturing and retail requirements. That is, the 'stable' compositions will yield no more than 10 %, preferably no more than 5 %, most preferred no more than 2% by volume phase separation as evidenced by appearance of 2 or more separate phases when stored at 25°C for 21 days from the time of preparation.
Preferably, compositions of the invention have a pH of between 6 and 14, more preferred from 6.5 to 13, especially preferred from 7 to 12.
Compositions of the invention preferably have a viscosity of less than 2,500 mPas at 21 s-l, more preferred less than 1,500 mPas, most preferred less than 1,000 mPas, especially preferred between 100 and 750 mPas at 21 s⁻¹.
Compositions of the invention also comprise detergent active materials, preferably at a level of from 1 to 70% by weight of the composition, more preferred a level of 5 to 40 % by weight, most preferred from 10 to 35 % by weight.
In the case of blends of surfactants, the precise proportions of each component which will result in lamellar structures will depend on the type(s) and amount(s) of the electrolytes, as is the case with conventional structured liquids.
In the widest definition the detergent-active material in general, may comprise one or more surfactants, and may be selected from anionic, cationic, nonionic, zwitterionic and amphoteric species, and (provided mutually compatible) mixtures thereof. For example, they may be chosen from any of the classes, sub-classes and specific materials described in 'Surface Active Agents' Vol.I, by Schwartz & Perry, Interscience 1949 and 'Surface Active Agents' Vol.II by Schwartz, Perry & Berch (Interscience 1958), in the current edition of "McCutcheon's Emulsifiers & Detergents" published by the McCutcheon division of Manufacturing Confectioners Company or in 'Tensid-Taschenbuch', H.Stache, 2nd Edn., Carl Hanser Verlag, München & Wien, 1981.
Suitable nonionic surfactants include, in particular, the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide, either alone or with propylene oxide. Specific nonionic detergent compounds are alkyl (C₆-C₁₈) primary or secondary linear or branched alcohols with ethylene oxide, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylenediamine. Other so-called nonionic detergent compounds include long chain tertiary amine oxides, long-chain tertiary phospine oxides and dialkyl sulphoxides.
Preferably the level of nonionic surfactant materials is from 1 -40 % by weight of the composition, more preferred from 2-20 %.
Compositions of the present invention may contain synthetic anionic surfactant ingredients, which are preferably present in combination with the above mentioned nonionic materials. Suitable anionic surfactants are usually water-soluble alkali metal salts of organic sulphates and sulphonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term alkyl being used to include the alkyl portion of higher acyl radicals. Examples of suitable synthetic anionic detergent compounds are sodium and potassium alkyl sulphates, especially those obtained by sulphating higher (C₈-C₁₈) alcohols produced, for example, from tallow or coconut oil, sodium and potassium alkyl (C₉-C₂₀) benzene sulphonates, particularly sodium linear secondary alkyl (C₁₀-C₁₅) benzene sulphonates; sodium alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from tallow or coconut oil and synthetic alcohols derived from petroleum; sodium coconut oil fatty monoglyceride sulphates and sulphonates; sodium and potassium salts of sulphuric acid esters of higher (C₈-C₁₈) fatty alcohol-alkylene oxide, particularly ethylene oxide, reaction products; the reaction products of fatty acids such as coconut fatty acids esterified with isethionic acid and neutralized with sodium hydroxide; sodium and potassium salts of fatty acid amides of methyl taurine; alkane monosulphonates such as those derived by reacting alpha-olefins (C₈-₂₀) with sodium bisulphite and those derived from reacting paraffins with SO₂ and Cl₂ and then hydrolyzing with a base to produce a random sulphonate; and olefin sulphonates, which term is used to describe the material made by reacting olefins, particularly C₁₀-C₂₀ alpha-olefins, with S0₃ and then neutralizing and hydrolyzing the reaction product. The preferred anionic detergent compounds are sodium (C₁₁-C₁₅) alkyl benzene sulphonates and sodium (C₁₆-C₁₈) alkyl sulphates.
Generally the level of the above mentioned non-soap anionic surfactant materials is from 1-40 % by weight of the composition, more preferred from 2 to 25 %.
It is also possible, and sometimes preferred, to include an alkali metal soap of a mono- or di-carboxylic acid, especially a soap of an acid having from 12 to 18 carbon atoms, for example oleic acid, ricinoleic acid, alk(en)yl succinate for example dodecyl succinate, and fatty acids derived from castor oil, rapeseed oil, groundnut oil,coconut oil, palmkernel oil or mixtures thereof. The sodium or potassium soaps of these acids can be used. Preferably the level of soap in compositions of the invention is from 1-35 % by weight of the composition, more preferred from 5-25 %.
Also possible is the use of salting out resistant active materials such as for example described in EP 328 177, especially the use of alkyl poly glycoside surfactants such as for example disclosed in EP 70 074. Also alkyl mono glucosides may be used.
The compositions optionally also contain electrolyte in an amount sufficient to bring about lamellar structuring of the detergent-active material. Preferably the compositions contain from 1% to 60%, especially from 10 to 45% of a salting-out electrolyte. Salting-out electrolyte has the meaning ascribed to in specification EP-A-79 646. Optionally, some salting-in electrolyte (as defined in the latter specification) may also be included.
In any event, it is preferred that compositions according to the present invention include detergency builder material, some or all of which may be electrolyte. In this context it should be noted that some detergent active materials such as for example soaps, also have builder properties.
Examples of phosphorus containing inorganic detergency builders include the water-soluble salts, especially alkali metalpyrophosphates, orthophosphates, polyphosphates and phosphonates. Specific examples of inorganic phosphate builders include sodium and potassium tripolyphosphates, phosphates and hexametaphosphates. Phosphonate sequestrant builders may also be used. Sometimes it is however preferred to minimise the amount of phosphate builders.
Examples of non-phosphorus-containing inorganic detergency builders, when present, include water-soluble alkali metal carbonates, bicarbonates, silicates and crystalline and amorphous aluminosilicates. Specific examples include sodium carbonate (with or without calcite seeds), potassium carbonate, sodium and potassium bicarbonates, silicates and zeolites.
In the context of inorganic builders, we prefer to include electrolytes which promote the solubility of other electrolytes, for example use of potassium salts to promote the solubility of sodium salts. Thereby, the amount of dissolved electrolyte can be increased considerably (crystal dissolution) as described in UK patent specification GB 1 302 543.
Examples of organic detergency builders, when present, include the alkaline metal, ammonium and substituted ammonium polyacetates, carboxylates, polycarboxylates, polyacetyl carboxylates and polyhydroxysulphonates. Specific examples include sodium, potassium, lithium, ammonium and substituted ammonium salts of ethylenediaminetetraacetic acid, nitrilitriacetic acid, oxydisuccinic acid, melitic acid, benzene polycarboxylic acids, CMOS, tartrate mono succinate, tartrate di succinate and citric acid. Citric acids or salts thereof are preferred builder materials for use in compositions of the invention.
In the context of organic builders, it is also desirable to incorporate polymers which are only partly dissolved, in the aqueous continuous phase as described in EP 301.882. This allows a viscosity reduction (due to the polymer which is dissolved) whilst incorporating a sufficiently high amount to achieve a secondary benefit, especially building, because the part which is not dissolved does not bring about the instability that would occur if substantially all were dissolved. Typical amounts are from 0.5 to 4.5% by weight.
It is further possible to include in the compositions of the present invention, alternatively, or in addition to the partly dissolved polymer, yet another polymer which is substantially totally soluble in the aqueous phase and has an electrolyte resistance of more than 5 grams sodium nitrilotriacetate in l00ml of a 5% by weight aqueous solution of the polymer, said second polymer also having a vapour pressure in 20% aqueous solution, equal to or less than the vapour pressure of a reference 2% by weight or greater aqueous solution of polyethylene glycol having an average molecular weight of 6000; said second polymer having a molecular weight of at least 1000. Use of such polymers is generally described in our EP 301,883. Typical levels are from 0.5 to 4.5% by weight.
Preferably the level of non-soap builder material is from 5-40 % by weight of the composition, more preferred from 5 to 25 % by weight of the composition.
Apart from the ingredients already mentioned, a number of optional ingredients may also be present, for example lather boosters such as alkanolamides, particularly the monoethanolamides derived from palm kernel fatty acids and coconut fatty acids, lather depressants, oxygen-releasing bleaching agents such as sodium perborate and sodium percarbonate, peracid bleach precursors, chlorine-releasing bleaching agents such as trichloroisocyanuric acid, inorganic salts such as sodium sulphate, and, usually present in very minor amounts, fluorescent agents, perfumes, enzymes such as proteases, amylases and lipases (including Lipolase (Trade Mark) ex Novo), enzyme stabilizers, antiredeposition agents, germicides and colorants.
Obviously in selecting the materials other than the polymer for use in compositions of the invention, also biodegradable materials are preferred for environmental reasons.
Compositions of the invention may be prepared by any conventional method for the preparation of liquid detergent compositions. A preferred method involves the dispersing of the electrolyte ingredient (if present) together with the minor ingredients except for the temperature sensitive ingredients -if any- in water of elevated temperature, followed by the addition of the builder material- if any-, the detergent active material (possibly as a premix) under stirring and thereafter cooling the mixture and adding any temperature sensitive minor ingredients such as enzymes perfumes etc. The deflocculating polymer may for example be added after the electrolyte ingredient or as the final ingredient. Preferably the deflocculating polymers are added prior to the formation of the lamellar structure.
In use the detergent compositions of the invention will be diluted with wash water to form a wash liquor for instance for use in a washing machine. The concentration of liquid detergent composition in the wash liquor is preferably from 0.1 to 10 %, more preferred from 0.1 to 3% by weight.
The invention will now be illustrated by way of the following Examples.

EXAMPLE I

The following polymers were tested for their biodegradability by using the Modified SCAS test (OECD Guidelines 302a, 1.5 litre).
Polymer A1 is of the basic formula I, wherein R1 is -CO-O-, R and R³ are absent, R⁴ is -C₁₄H₂₉, R⁵ is -COONa, R⁶ is -CH₃, R¹ is -CO-CH₃, A and A³ are Na, x is 0, q:y is 1 : 1, (q+y):z is 25:1, Mw (cf n) is 12,400.
Polymer B1 was of formula II wherein R and R³ are absent, R⁴ is -C₁₄H₂₉, R⁷ is -OH, m:n is 75, R¹ is -O, Mw (cf w) is 10,000, R^7'= -oH or -R¹-R-R³-R⁴.
Polymer C1 was of the basic structure of formula III, wherein y is zero, x is 25, R⁹ is -CH₂-, R⁶ is -CH₃, R⁵ is -H, S is -COCH₂C(OH) (COOA¹)CH₂COOA¹, A¹ is Na, R^l is -CO-O-, R and R³ are absent, R⁴ is -C₁₂H₂₅, Mw (cf n) is 24,000.
Polymer D1 was of the basic formula IV, wherein A¹ is -Na, R¹¹ is
is -C₁₄H₂₉, A is -C₁₄H₂₉. Q¹:Q is 25 :1, Mw (cf n) is 2,500, D is -H
The following removal percentages were found in the modified SCAS test:
The SCAS effluent is used as the inoculum in a modified Sturm test-system and the following conversion percentages were obtained:
From these results it appears that polymers A1 to D1 all are within our definition of biodegradability because they provide more than 80 % removal in the modified SCAS test, while the comparative polymer as disclosed in EP 346 995 is outside our biodegradability definition by both tests. The results of using the effluent of the SCAS test as the inoculum in a Sturm test-system indicate that polymers B1 and D1 are in the preferred class of biodegradable materials because they also show more than 60 % conversion in this test. Because of its good deflocculating properties combined with the preferred improved biodegradability, polymers B1 and other polysugars (preferably of formula II or IIa) are preferred embodiments of biodegradable deflocculating polymers according to the invention.

EXAMPLE II

The following compositions were prepared by either adding the citrate together with sufficient NaOH to neutralise the active materials and to bring the pH of the final composition to 7, to water at a temperature of 30 °C under stirring, followed by addition of the deflocculating polymer and a premix of the Synperonic and Dobs (in acid form) (Method abbreviated WEPA) or by using the same order of addition except that the polymer is now added after the premix of the surfactants (Method abbreviated WEAP).

INGREDIENT % (wt) A B C

NaDobs 24.4 24.5 30.0

Synperonic A7 10.4 9.9 12.9

NaCitrate 2aq 13.0 16.4 14.3

Water 52.2 49.2 42.8

polymer % on top of formulation
Polymers B1 to B6 are of the basic structure of formula II, wherein R and R³ are absent, R⁴ is -C₁₄H₂₉, R⁷ is -OH, R^7' is -OH or -R¹-R-R³-R⁴;

Polymer m:n R¹ Mw (cf v and w)

B1 75 -O- 10,000

B2 30 -OCH₂CONH 10,000

B3 75 -O- 4,000

B4 95 -O- 15,000

B5 150 -O- 35,000

B6 90 -O- 60,000
The following results were obtained
All compositions other than the comparative formulations 1, 8 and 25 did not not yield the rapid phase separation as observed in the comparative formulations. Compositions 28 and 29 were tested for their physical stability, both were stable (no phase separation upon storage for 21 days at 25 °C). It is believed that the viscosity reduction and the stability increase upon addition of the deflocculating polymers is an indication of deflocculating effectiveness of the polymer materials. Confirmation of this can be found in the visual appearance of the product and from microscopical observations.
The good deflocculating properties of the hydrophobically modified polysugars in combination with their excellent biodegradability (see example I) renders these polymers particularly preferred for use in compositions of the invention.

Example III

The following polymers in accordance to formula I were incorporated into the formulations as indicated in Example II.
Polymers A1 and A2 are of the basic structure of formula I, wherein for A1 and A2 R₁ is -CO-O-, R and R³ are absent, R⁴ is -C₁₄H₂₉, R⁵ is -COONa, R⁶ is CH₃, R¹ is -CO-CH₃, A¹ to A³ is Na, x is zero, q:y is 1:1, (q+y):z is 25:1. The molecular weight (cf n) of A1 is 12,400, the Mw of A2 is 49,000.
Polymers A3 to A6 are also in accordance to formula I, wherein R₁ is -CO-O-, R and R³ are absent, R⁴ is -C₁₂H₂₅, R⁵ is -H, R⁶ is -CH₃, A¹ is Na, y is zero, q:x is 1:1, (q+x):z is 25:1 B¹= -H. For A3 R¹ is -CO-CH₃ and the mW (cf n) is 4,500, for A4 R¹ ₂ is -H and the Mw is 2,800, for A5 R¹ is -CO-CH₃ and the Mw is 4,300, for A6 R¹ is -H and the Mw is 3,100.
Polymer A7 is in accordance with formula I, wherein R¹ is -CO-O-, R and R³ are absent, R⁴ is -C₁₃H₂₇, R⁵ is -H, R¹ is -CO-CH₃ or -CO-CH₂-CH₂-COONa while the ratio of -CO-CH₃ groups to -CO-CH₂-CH₂-COONa is 25 : 70, x and y are zero, q:z is 19:1 and the Mw (cf n) is 1,500.
The following results were obtained:
Similar results could be obtained by using similar polymers like polymer A3, A5 or A6.

Claims

A liquid detergent composition comprising a dispersion of lamellar droplets of detergent active material in an aqueous continuous phase, said composition also comprising a deflocculating polymer selected from the group consisting of:
(I) polymers having a hydrophilic backbone and one or more hydrophobic side-chains;

(II) hydrophobically modified polysaccharides;

(III) polymers of formula:
wherein: z is 1 and n is at least 1; (x+y) : z is from 4 : 1 to 1,000 : 1; wherein the monomer units may be in random order;

R¹ represents -CO-O-, -O-, -O-CO-, -CH₂-, -CO-NH- or is absent;

R represents from 1 to 50 independently selected alkyleneoxy groups, or is absent, provided that when R³ is absent and R⁴ represents hydrogen or contains no more than 4 carbon atoms, then R must contain an alkyleneoxy group preferably more than 5 alkyleneoxy groups with at least 3 carbon atoms;

R³ represents a phenylene linkage, or is absent;

R⁴ represents hydrogen or a C₁₋₂₄ alkyl or C₂₋₂₄ alkenyl group, with the proviso that when R is absent, R⁴ is not hydrogen and when also R³ is absent, then R⁴ must contain at least 5 carbon atoms;

R⁵ represents hydrogen or a group of formula -COOA⁴;

R⁶ represents hydrogen or C₁₋₄ alkyl;

R⁸ and R⁹ represent -CH₂- or are absent;

S¹ and S are independently selected from -CO(CH₂)₂COOA¹, -CO(CH)₂COOA¹, -COCH₂C(OH) (COOA¹)CH₂COOA¹, -COCH₂COOA¹, -CO(CH(OH))₂COOA¹, -COCH₂CH(OH)COOA¹, -COCH₂CH(CH₃)COOA¹ and -COCH₂C(=CH₂)COOA¹;

A¹ is independently selected from hydrogen, alkali metals, alkaline earth metals, ammonium and amine bases and C₁₋₄, or (C₂H₄O)_tH wherein t is from 1-50, and wherein the monomer units may be in random order; and

(IV) polymers of formula:
wherein:

D is -H or -OH; n is at least 1;

A is
wherein:

each A is A¹ or R¹⁰;

Q¹ : Q is from 4 : 1 to 1,000 : 1;

R¹⁰ represents a C₅₋₂₄ alk(en)yl group;

B is ---O---CO---R¹¹---CO----;

R¹¹ represents -CH₂-, -C₂H₄-, -CC₃H₆-, or an aryl link said aryl link optionally being substituted with one or more -COOA¹ groups or a benzophenone link;

A¹ is independently selected from hydrogen, alkali metals, alkaline earth metals, ammonium and amine bases and C₁₋₄, or (C₂H₄O)_tH wherein t is from 1-50, and wherein the monomer units may be in random order;

said polymer satisfying one or more of the following biodegradability tests:
(a) Modified Sturm test;

(b) Modified SCAS test;

(c) Combined modified SCAS test and Sturm test;

(d) Batch activated sludge test of ¹⁴C labelled polymers;

(e) Soil biodegradation tests of ¹⁴CO₂ labelled polymers;

(f) Anaerobic Batch test of ¹⁴C labelled polymers;

(g) Continuous activated sludge simulation tests; and

(h) Continuous activated sludge simulation test using radio labelled polymers.
A liquid detergent composition according to claim 1, wherein the deflocculating polymer is a hydrophobically modified polysugar.
A liquid detergent composition according to claim 2, wherein the polysugar is a hydrophobically modified dextran preferably having a Mw of 2,000 to 20,000.
A liquid detergent composition according to claim 1, having a viscosity of less than 2,500 mPas at 21 s-1.
A liquid detergent composition according to claim 1 comprising from 0.01 - 5 % by weight of deflocculating polymers.
A liquid detergent composition according to claim 1 having a pH of from 6 to 14.
A liquid detergent composition according to claim 1, comprising from 1-70 % by weight of detergent active materials.
A liquid detergent composition according to claim 1 yielding less than 10% by volume phase separation when stored at 25°C for 21 days from the day of preparation.