DE69025770T2 - LIQUID DETERGENT - Google Patents

Description

The present invention relates to liquid detergents, in particular to liquid detergents comprising a dispersion of lamellar droplets in an aqueous continuous phase.

Lamellar droplets are a special class of surfactant structures that are known from numerous literature sources, for example from H.A. Barnes, "Detergents", Chapter 2, in K. Walters (ed.), "Rheometry: Industrial Applications", J. Wiley & Sons, Letchworth 1980.

Such lamellar dispersions are used to impart such properties as consumer-preferred flow and/or hazy appearance. Many are also capable of suspending particulate solids such as detergent builders or abrasive cloths. Examples of such structured liquids without suspended particles are given in US Patent 4,244,840, while examples in which solid particles are suspended are disclosed in the specifications EP-A-160 342; EP-A-38 101; EP-A-140 452 and also in the above-mentioned US-A-4,244,840. Others are described in European Patent Application EP-A-151 884, in which the lamellar droplets are called "spherulites".

The presence of lamellar droplets in a liquid detergent product can be determined by means known in the art, for example optical techniques, various rheometric measurement techniques, X-ray or neutron scattering and electron microscopy.

The droplets consist of an onion-skin-like configuration of concentric bilayers of surfactant molecules between which water or electrolyte solution (aqueous phase) is enclosed. Systems in which such droplets are densely packed provide a quite desirable combination of physical stability and solid-suspending properties with useful flow properties.

The viscosity and stability of the product depends on the volume fraction of liquid occupied by the droplets. Generally speaking, if the volume fraction is about 0.6, the droplets are just touching each other (space filling). This allows reasonable stability with acceptable viscosity (i.e. greater than 2.5 Pas, preferably not more than 1 Pas at a shear rate of 21 s-1). This volume fraction also imparts useful solid-suspending properties.

A problem with formulating detergents with high volume of lamellar phase is the possible instability and/or high viscosity of the product. These problems are fully described in our pending European patent application 89201530.6 (EP 346 995).

One problem with formulating detergents containing polymeric ingredients is that these agents are sometimes less preferred for environmental reasons because the polymeric ingredients are often less biodegradable.

We have now found that the dependence of stability and/or viscosity on volume fraction can be favorably influenced and the above-mentioned environmental side effects of polymers can be reduced by incorporating a biodegradable deflocculant into a lamellar detergent.

Accordingly, the present invention relates to a liquid detergent comprising a dispersion of lamellar droplets in an aqueous continuous phase, which composition also comprises a biodegradable deflocculating polymer selected from the four classes described below.

The deflocculation polymer

Suitable types of deflocculating polymers for use in the compositions of the present invention are described, for example, in our co-pending European Patent Application 89201530.6 (EP 346 995) (published December 20, 1989) and in our unpublished patent applications WO/91/06622 (published May 16, 1991), WO/91/06623 (published May 16, 1991) and GB-A-2 237 813 (published May 15, 1991). Of the general classes of polymers described in these patent documents, only the use of biodegradable polymers is included within the scope of the present invention. It is believed that the skilled person, on the basis of the generally known knowledge of polymer degradability combined with the teachings of the above-mentioned non-prepublished patent applications, will be able to select those deflocculating polymers suitable for use in the composition of the invention.

Suitable tests for determining biodegradability are given in the OECD guidelines. Other suitable tests include the examination of CO₂ released after decomposition of the polymer material, in these tests 14C-labelled polymers can sometimes be used. Although it is preferred that polymers for use in the composition of the invention satisfy most or all of the available tests, users have found that polymers which satisfy one or more biodegradability tests are suitable for use in the present invention.

Polymers for use in agents according to the invention must satisfy one or more of the following tests:

(a) Modified Sturm test as described in OECD Guideline 301b. This test measures the 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 from this test are not completely reliable; biodegradable materials may fail this test.

(b) Modified SCAS test as described in OECD Guideline 302a. This test measures the removal of test material by analysis of dissolved organic carbon. It is assumed that 80% removal is a reasonable indication of biodegradability or adsorption.

(c) Combined modified SCAS test and Sturm test. This test includes a modified SCAS test as described above, in which the SCAS wastewater is used as inoculum in a modified Sturm test system. A 60% conversion to CO2 in the Sturm system using acclimated SCAS inoculum is considered to be indicative of inherent biodegradability.

(d) Batch activated sludge test of 14C-labelled polymers. This determines whether 14CO2 can be detected during 6 weeks incubation at ambient temperature. Detected 14CO2 is an indication of biodegradability, the amount of 14CO2 detected is a measure of the degree of biodegradability. For example, an amount of detected 14CO2 corresponding to more than 20% by weight of the initial carbon-14 content of the test material after 100 days is considered to indicate reasonable biodegradability, while more than 50% by weight would be considered to indicate very good biodegradability.

(e) Soil biodegradability test of ¹⁴CO₂ labelled polymers. This test determines whether ¹⁴CO₂ from the applied test material can be detected on soil during 100 days of incubation at ambient temperature. Detected ¹⁴CO₂ is an indication of biodegradability. The amount of ¹⁴CO₂ detected is a measure of the degree of biodegradability. For example, an amount of detected ¹⁴CO₂ corresponding to more than 40 or 50 weight percent of the initial carbon content of the test material would be an indication of very good biodegradability.

(f) Anaerobic batch test for 14C-labeled polymers. This test determines whether radiolabeled CH4 or CO2 can be detected after incubating a batch of material at ambient temperature for 28 days under anaerobic conditions. Detected 14CO2 or 14CH4 is an indication of biodegradability and the amount of 14CO2 or 14CH4 detected is a measure of the degree of biodegradability. For example, an amount of detected 14CO2 or 14CH4 equal to more than or 50% by weight of the initial carbon-14 content of the test material would be an indication of very good biodegradability.

(g) Continuous activated sludge simulation tests. In this test, the material is continuously dosed. After After an adjustment 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 assumed that 80% removal is a reasonable indication of biodegradability or adsorption.

(h) Continuous activated sludge simulation test using radiolabeled polymers. In this test, non-radiolabeled polymer is continuously dosed and radiolabeled polymer is dosed only after the adaptation period of 2 months. During the period of radiolabeled polymer dosing, the amount of C-14 appearing in the wastewater on sludge solids and that released as 14CO2 are determined. It is assumed that 80% removal of dosed C-14 is a reasonable indication of either biodegradability or adsorption. Detected 14CO2 is an indication of biodegradability. A yield corresponding to 10% by weight of the initial radiocarbon content indicates 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 greater than 80% removal in the modified SCAS test and greater than 60% conversion in the Sturm test system using a SCAS inoculum. Polymers providing less than 80% removal in the modified SCAS test are less preferred for use in the compositions of the invention, while compositions providing greater 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 the compositions of the invention.

The first class of polymers for use in agents according to the invention are biodegradable polymers with a hydrophilic backbone and at least one hydrophobic side chain. The basic structure of polymers with a hydrophobic backbone and one or more hydrophobic side chains is described in EP 89201530.6 (EP 346 995).

In general, the hydrophilic backbone of the polymer is predominantly linear (the main chain of the backbone makes up at least 50%, preferably more than 75%, most preferably more than 90% by weight of the backbone), suitable monomer components 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 glycerin. Examples of suitable monomer units are acrylic acid, α-hydroxyacrylic acid, α-hydroxy acid, methacrylic acid, malic acid, vinylacetic acid, glucosides, ethylene oxide and glycerin. The hydrophilic scaffold, made from the scaffold components in the absence of hydrophobic side groups, becomes relatively water-soluble at ambient temperature and a pH between 6.5 and 14.0.

Preferred is a solubility of more than 1 g/l, more preferably more than 5 g/l, most preferably more than 10 g/l.

Preferably, the hydrophobic side groups are composed of relatively hydrophobic alkoxy groups, for example butylene oxide and/or propylene oxide and/or alkyl or alkenyl chains with 5 to 24 carbon atoms. The hydrophobic groups can be linked to the hydrophilic framework directly or via relatively hydrophilic bonds, for example a polyethoxy bond.

Preferred polymers are of the formula:

wherein z is 1, q is preferably at least 1, (q+x+y) : z is 4:1 to 1000:1, preferably 6:1 to 250:1, wherein the monomer units may be in random order; y is preferably 0 to the value 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;

R² represents 1 to 50 independently selected alkyleneoxy groups, preferably ethylene oxide or propylene oxide groups, or is absent, with the proviso that if R³ is absent, R⁴ represents hydrogen or contains not more than 4 carbon atoms, then R² must contain an alkyleneoxy group, preferably more than 5 alkyleneoxy groups having at least 3 carbon atoms;

R³ represents a phenylene bond or is not present;

R⁴ represents hydrogen or a C₁₋₂₄ alkyl or C₁₋₂₄ alkenyl group, with the proviso that when R² is not present, R⁴ is not hydrogen, and when R³ is also not present, then R⁴ must contain at least 5 carbon atoms;

R⁵ represents hydrogen or a group of the formula -COOA⁴ ;

R⁶ represents hydrogen or C₁₋₄alkyl;

R¹² represents -H, -CO-CH₃, -CH-COOA⁴, -CO-CH₂-CH₂-COOA⁴, -CH₂-CH=CH-COOA⁴, -CO-CH₂-COOA⁴ or -CO-CH₂-CH=CHCOOA⁴ .

A¹, A², A³ and A⁴ are independently selected from hydrogen, alkali metals, alkaline earth metals, ammonium and amine bases and C₁₋₄, or (C₂H₄O)tH, where t is 1 to 50 and where the monomer units can be in random order.

Each B¹ is independently selected from -CH₂OH, -OH or -H.

Each monomer unit for R¹-R¹², A¹-A⁴ and B¹ can be independently selected from the groups mentioned above.

The second class of polymers for use in the present compositions are hydrophobically modified polysaccharides. Possible sugar moieties for use in these polymers include glucosides and fructosides, for example maltoses, fructoses, lactoses, glucoses and galactoses. Mixtures of sugar groups may also be used. The sugar groups may be linked to one another via any bond, although 1-4 bonds and/or 1-6 bonds and/or 1-2 bonds are preferred. The polysaccharides are preferably predominantly linear, but branched polymers may also be used. Particularly preferred is the use of hydrophobically modified dextrans, more preferably dextran having a molecular weight of 2000 to 20,000. An example of a preferred polysaccharide has the following formula:

wherein:

each R⁷' represents R⁷ or -R¹-R²-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-R²-R³-R⁴ groups per molecule; n is at least 1;

m is the total number of R⁷ and R⁷' groups other than -R¹-R²-R³-R⁴;

The ratio m:n is 12:1 to 3000:1, preferably 18:1 to 750:1, where the monomer units can be in any 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-;

R²⊃min;⊃4; are as defined for formula I;

A¹ is defined as for formula I.

A second example of a preferred hydrophobically modified polysugar is of the formula:

wherein R⁷, R⁷', 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 according to 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 4:1 to 1000:1, preferably 6:1 to 250:1, y is preferably 0 up to a maximum value equal to the value of x; wherein the monomer units can be in random order,

R¹⊃min;⊃6 are as defined for formula I;

R⁸ and R⁹ represent -CH₂- or are absent;

S¹ and S² 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 have the formula:

where: D represents -H or -OH and n is at least 1 is;

wherein:

A² represents A¹ or R¹⁰ respectively;

Q¹ : Q² is 4 : 1 to 1000 : 1, preferably 6 : 1 to 250 : 1;

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

B represents -O-CO-R¹¹-CO-;

R¹¹ represents -CH₂-, -C₂H₄-, -C₃H₆- or an aryl bond wherein the aryl bond is optionally substituted with one or more -COOA¹- groups or a benzophenone bond;

A¹ is as defined for formula I.

Preferably, polymers for use in the compositions have a molecular weight (determined as in our pending European Patent Application 346 995) of between 500 and 500,000. Polymers according to formulas II-IV preferably have a molecular weight of 500-250,000, more preferably 1,000-100,000, most preferably 2,000-50,000. Polymers according to formula I are preferably low molecular weight polymers, preferably having a molecular weight of less than 50,000, more preferably less than 10,000, particularly preferably less than 5,000, most preferably 500 to 2,000. The polymers for use in detergents according to the invention can be prepared using conventional polymerization processes, for example radical polymerization or condensation polymerization. Suitable methods are described, for example, in the above-mentioned also pending European patent application.

Generally, the deflocculant polymer is used in an amount of 0.01 to 5% by weight of the composition, more preferably 0.1 to 3.0%, most preferably 0.25 to 2.0%.

Without wishing to be bound by any particular interpretation or theory, applicants have hypothesized that the polymers act on the composition according to the following mechanism. The hydrophobic side chain(s) or ionic groups could be mixed into or onto the outer bilayer of the droplets, leaving the hydrophilic or non-ionic backbone via the outside of the droplets and/or the polymers could be mixed deeper into the droplet.

If the hydrophobic side chains or ionic groups are mixed mainly into or onto the outer bilayer of the droplets, this will have an effect on decoupling the inter- and intra-droplet forces, i.e. the difference between the forces between individual surfactant molecules in adjacent layers within a given droplet and those between surfactant molecules in adjacent droplets could be increased to the same extent by decreasing the forces between adjacent droplets. This generally results in increased stability due to less flocculation and a decrease in viscosity due to smaller inter-droplet forces leading to larger distances between adjacent droplets.

As the polymers penetrate deeper into the droplets, less flocculation will occur, leading to an increase in stability. The influence of these polymers within the droplets on viscosity is determined by two opposing effects: first, the presence of deflocculating polymers will lower the forces between adjacent droplets, leading to larger interdroplet spacing, which in turn generally leads to a lower viscosity of the system; second, the forces between the layers in the droplets are equally reduced by the presence of the polymer in the droplet. This generally results in a reduction in layer thickness, therefore increasing the lamellar volume of the droplets and therefore increasing viscosity. The overall effect of these two opposing effects can result in either a reduction or an increase in the viscosity of the product.

The agents according to the invention are physically stable and have a relatively low viscosity, i.e. a corresponding agent minus the deflocculant polymer is less stable and/or has a higher viscosity.

In the context of the present invention, the physical stability of these systems can be defined in terms of the maximum separation compatible with most manufacturing and commercial requirements. That is, the "Stable" compositions will give rise to not more than 10%, preferably not more than 5%, most preferably not more than 2% by volume phase separation as evidenced by the presence of 2 or more separate phases upon storage at 25°C for 21 days from the time of preparation.

Preferably, the compositions of the invention have a pH between 6 and 14, more preferably 6.5 to 13, especially preferably 7 to 12.

Compositions according to the invention preferably have a viscosity of less than 2500 mPas at 21 s⁻¹, more preferably less than 1500 mPas, most preferably less than 1000 mPas, in particular between 100 and 750 mPas at 21 s⁻¹.

Compositions according to the invention also comprise detergent actives, preferably at a level of 1 to 70% by weight of the composition, more preferably at a level of 5 to 40% by weight, most preferably 10 to 35% by weight.

In the case of surfactant mixtures, the exact ratios for each component leading to lamellar structures will depend on the type(s) and amount(s) of electrolytes, as in the case of conventional structured fluids.

In the broadest definition, the detergent active material may generally comprise one or more surfactants and may be selected from anionic, cationic, nonionic, zwitterionic and amphoteric forms and (provided they are compatible with each other) mixtures thereof. For example, they may be selected from any of the classes, subclasses and specific materials set out in "Surface Active Agents", Vol. 1, by Schwartz & Perry, Interscience 1949 and "Surface Active Agents", Vol. II, by Schwartz, Perry & Berch, Interscience 1958 and in the current edition of "McCutcheon's Emulsifiers &Detergents" published by McCutcheon's Division of Manufacturing Confectioners Company or in the "Surfactant Pocket Book", H. Stache, 2nd edition, Carl Hanser Verlag, Munich & Vienna, 1981.

Suitable nonionic surfactants are in particular the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example aliphatic alcohols, acids, amides or alkylphenols with alkylene oxides, in particular ethylene oxide, either individually or with propylene oxide. Typical nonionic surfactant compounds are alkyl (C6-C18) primary or secondary linear or branched alcohols with ethylene oxide and products prepared by condensation of ethylene oxide with the reaction products of propylene oxide and ethylenediamine. Other so-called nonionic surfactant compounds are long-chain tertiary amine oxides, long-chain tertiary phosphine oxides and dialkyl sulfoxides.

Preferably, the amounts of non-ionic surfactants are more than 1 to 40% by weight of the agent, preferably 2 to 20% by weight of the agent.

Compositions of the present invention may contain synthetic anionic surfactant ingredients, preferably in combination with the nonionic materials mentioned above. Suitable anionic surfactants are conventional water-soluble alkali metal salts of organic sulfates and sulfonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term alkyl as used including the alkyl radical of higher acyl radicals. Examples of suitable synthetic anionic surfactant compounds are sodium and potassium alkyl sulfates, particularly those obtainable by sulfonating higher (C8-C18) alcohols prepared, for example, from tallow or coconut oil, sodium and potassium alkyl (C9-C20) benzene sulfonates, particularly linear secondary alkyl (C10-C15) benzene sodium sulfonate; Sodium alkyl glyceryl ether sulfates, particularly those ethers of higher alcohols derived from tallow or coconut oil and synthetic alcohols derived from petroleum; sodium coconut oil fatty acid monoglyceride sulfates and sulfonates; sodium and potassium salts of reaction products of sulfuric acid esters of higher (C₈-C₁₈) fatty alcohol alkylene oxide, particularly ethylene oxide; 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 methyltaurine; alkane monosulfonates such as those derived by reacting alpha-olefins (C8-C20) with sodium bisulfite and those derived from the reaction of paraffin with SO2 and Cl2 followed by hydrolysis with a base to produce a randomly sulfonated product; and olefin sulfonates, which term is used to describe the material obtained by reacting olefins, particularly C10-C20 alpha-olefins, with SO3 followed by neutralization and hydrolysis of the reaction product. The preferred anionic surfactant compounds are sodium (C₁₁-C₁₅) alkylbenzenesulfonates and sodium (C₁₆-C₁₈) alkylsulfates.

In general, the proportion of the above-mentioned non-soap anionic surfactant materials will be 1-40% by weight of the composition, more preferably 2 to 25%.

It is also possible and sometimes preferred to add an alkali metal soap of a mono- or dicarboxylic acid, in particular a soap of an acid having 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, peanut oil, coconut oil, palm kernel oil or mixtures thereof. The sodium or potassium soaps of these acids can be used. Preferably the proportion of soap in the compositions of the invention is 1-35% by weight of the composition, more preferably 5-25%.

It is also possible to use salting-resistant active substances, as described for example in EP 328 177 and in particular the use of alkyl polyglycoside surfactants as disclosed for example in EP 70 074. Alkyl monoglucosides can also be used.

The agents optionally also contain electrolyte in an amount sufficient to create a somewhat lamellar structure of the detergent material. The agents preferably contain 1 to 60, in particular 10 to 45%, of a salting-out electrolyte. The term salting-out electrolyte has been explained as to its importance in the description of EP-A-79 646. Optionally, some salting electrolyte (as defined in the later parts of the description) may also be included.

In any event, it is preferred that compositions according to the invention containing detergent builder material may contain some or all of the electrolyte. In this connection, it should be noted that some detergent materials, for example soaps, also have builder properties.

Examples of phosphorus-containing inorganic detergent builders are water-soluble salts, particularly alkali metal pyrophosphates, orthophosphates, polyphosphates and phosphonates. Specific examples of inorganic phosphate builders are sodium and potassium tripolyphosphates, phosphates and hexametaphosphates. Phosphonate sequestering builders may also be used. However, it is sometimes preferred to reduce the amount of phosphate builders.

Examples of non-phosphorus inorganic detergent builders, when present, are water-soluble alkali metal carbonates, bicarbonates, silicates and crystalline and amorphous aluminosilicates. Specific examples are sodium carbonate (with or without calcite nuclei), potassium carbonate, sodium and potassium bicarbonates, silicates and zeolites.

In connection with inorganic builders, we prefer the addition of electrolytes that promote the solubility of other electrolytes, for example the use of potassium salts to improve the solubility of sodium salts. This can significantly increase the amount of dissolved electrolyte (crystal solution), as described in British Patent Specification GB 1 302 543.

Examples of organic detergent builders, when present, are alkali metal, ammonium and substituted ammonium polyacetates, carboxylates, polycarboxylates, polyacetylcarboxylates and polyhydroxysulfonates. Specific examples are sodium, potassium, lithium, ammonium and substituted ammonium salts of ethylenediaminetetraacetic acid, nitrilotriacetic acid, oxydisuccinic acid, mellitic acid, benzenepolycarboxylic acids, CMOS, tartrate monosuccinate, tartrate disuccinate and citric acid. Citric acids or salts thereof are preferred builder materials for use in the compositions according to the invention.

In connection with organic builders, it is also beneficial to add polymers that are only partially dissolved in the aqueous continuous phase, according to EP-A-301 882. This allows a viscosity reduction (due to the polymer being dissolved) while adding a sufficiently high amount to achieve a secondary beneficial effect, in particular builder effect, due to the partially undissolved, would not cause instability that would occur if essentially all was dissolved. Typical amounts are from 0.5 to 4.5 wt.%.

It is also possible to add to the agents according to the invention, as an alternative to or in addition to the partially dissolved polymer, another polymer which is essentially completely soluble in the aqueous phase and has an electrolyte resistance of more than 5 g of sodium nitrilotriacetate in 100 ml of a 5% by weight aqueous solution of the polymer, the second polymer also having a vapor pressure in 20% aqueous solution which is equal to or less than the vapor pressure of a comparative aqueous solution of 2% by weight or more of polyethylene glycol with an average molecular weight of 6000; and the second polymer having a molecular weight of at least 1000. The use of such polymers is generally described in our EP-A-301 883. Typical concentrations are from 0.5 to 4.5% by weight.

Preferably, the concentration of non-soap builder material is 5-40% by weight of the composition, more preferably 5 to 25% by weight of the composition.

In addition to the components already mentioned, a number of optional components may also be present, for example foam improvers such as alkanolamides, in particular monoethanolamides derived from palm kernel fatty acids and coconut fatty acids, foam inhibitors, 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 in very small quantities, fluorescent agents, perfumes, enzymes such as proteases, amylases and lipases (including Lipolase (registered trademark) from Novo), enzyme stabilisers, anti-deposit agents, germicides and colouring agents.

Of course, when selecting materials other than the polymer for use in the compositions according to the invention, biodegradable materials are also preferred for environmental reasons.

Compositions according to the invention can be prepared by conventional processes for preparing liquid detergents. A preferred process involves dispersing the electrolyte component (if present) together with the minor components, excluding the temperature-sensitive components, if present, in water at an elevated temperature, followed by the addition of the builder material, if present, the detergent active (optionally as a premix) with stirring and then cooling the mixture and adding temperature-sensitive minor components, such as enzymes, perfumes, etc. The deflocculating polymer can, for example, be added after the electrolyte component or as the last component. The deflocculating polymers are preferably added before the formation of the lamellar structure.

When using the detergents according to the invention, they are diluted with washing water to form a washing liquor, for example for use in a washing machine. The concentration of liquid detergent in the washing liquor is preferably 0.1 to 10%, more preferably 0.1 to 3% by weight.

The invention will now be explained using the following examples.

EXAMPLE 1

The following polymers were tested for biodegradability using the modified SCAS test (OECD Guidelines 302a, 1.5 liters).

Polymer A1 of the basic formula I, wherein R1 represents -CO-O- , R2 and R3 are absent, R4 represents -C14H29, R5 represents -COONa, R6 represents -CH3, R12 represents -CO-CH3, A2 and A3 represent Na, x is 0, q:y is 1:1, (q+y):z is 25:1 , Mw (cf n) is 12400.

Polymer B1 had the formula II, wherein R2 and R3 were absent, R4 is -C14H29, R7 is -OH, m:n is 75, R1 is -O-, Mw (cf w) is 10000, R7'= -OH or -R1-R2-R3-R4.

Polymer C1 had the basic structure of formula III, wherein y is 0, x is 25, R9 is -CH2-, R6 is -CH3 , R5 is -H, S2 is -COCH2C(OH)(COOA1)CH2COOA1, A1 is Na, R1 is -CO-O-, R2 and R3 are absent, R4 is -C12H25, Mw (cf n) is 24000.

Polymer D1 had the basic formula IV, where A¹ represents -Na, R¹¹

R¹⁰ represents -C₁₄H₂₉, A² represents -C₁₄H₂₉, Q¹:Q² is 25:1, Mw (cf n) is 2500, D is -H.

The following removal percentages were found in the modified SCAS tests: Polymer % Removal Comparison* * Polymer A-11 as described in EP 346 995.

The SCAS wastewater is used as inoculum in a modified Sturm test system and the following conversion percentages were obtained: Polymer % Conversion Comparison*

From these results it is clear that polymers A1 to D1 all fall within our definition of biodegradability because they provide greater than 80% removal in the modified SCAS test, while the control polymer as disclosed in EP 346 995 falls outside our biodegradability definition for both tests. The results of using the effluent of the SCAS test as inoculum in a Sturm test system show that polymers B1 and D1 are in the preferred class of biodegradable materials because they also show greater than 60% conversion in these tests. Due to their good deflocculation properties combined with the preferred improved biodegradability, polymers B1 and other polysugars (preferably of formula II or IIA) are preferred embodiments of the biodegradable deflocculation polymers according to the invention.

EXAMPLE II

The following compositions were prepared by either adding the citrate together with sufficient NaOH to neutralize the actives and bring the final composition pH to 7, to water at a temperature of 30ºC with stirring, followed by addition of the deflocculating polymer and a premix of Synperonic and Dobs (in acid form) (Procedure abbreviated WEPA) or using the same order of addition except that the polymer is now added after the premix of surfactants (Procedure abbreviated WEAP). Ingredient Weight Percent NaDobs Synperonic A7 Sodium Citrate 2aq Water Polymer % Formulation Replenishment

Polymers B1 to B6 are of the basic structure of formula II, wherein R² and R³ are not present, R⁴ represents -C₁₄H₂₉, R⁷ represents -OH, R⁷' represents -OH or -R¹-R²-R³-R⁴; polymer

The following results were obtained Base Viscosity Comparison Polymer Method mPa s at 21 s⊃min;¹ * Results may not be reliable due to rapid phase separation.

All compositions except those of comparative formulations 1, 8 and 25 did not result in rapid phase separation as observed in the comparative formulations. Compositions 28 and 29 were tested for physical stability, both were stable (no phase separation after storage for 21 days at 25ºC). It is believed that the viscosity reduction and stability increase after addition of the deflocculant polymers is an indication of deflocculant effectiveness of the polymer materials. Confirmation of this can be found from the visual appearance of the product and from microscopic observations.

The good deflocculation properties of these hydrophobically modified polysugars in combination with their excellent biodegradability (see Example 1) results in these polymers being particularly preferred for use in compositions of the invention.

EXAMPLE III

The following polymers according to formula I were mixed into the formulations as given in Example II.

Polymers A1 and A2 are of the basic structure of Formula I, wherein for A1 and A2, R¹ represents -CO-O-, R² and R³ are absent, R⁴ represents -C₁₄H₂₉, R⁵ represents -COONA, R⁶ represents CH₃, R¹² represents -CO-CH₃, A¹ to A³ represents Na, x is 0, q:y is 1:1, (q+y):z is 25:1. The molecular weight (cf n) of A1 is 12400, the Mw of A2 is 49000.

Polymers A3 to A6 are also according to formula I, wherein R¹ is -CO-O-, R² and R³ are absent, R⁴ is -C₁₂H₂₅, R⁵ is -H, R⁶ is -CH₃, A¹ is Na , y is 0, q:x is 1:1, (q+x):z is 25:1, B¹=-H. For A3, R¹² is -CO-CH₃ and the Mw (cf n) is 4500, for A⁴, R¹² is -H and the Mw is 2800, for A5, R¹² is -CO-CH₃ and the Mw is 4300, for A6 R¹² is -H and the Mw is 3100.

Polymer A7 is according to formula I, wherein R¹ represents -CO-O- , R² and R³ are absent, R⁴ represents -C₁₃H₂₇, R⁵ represents -H, R¹² represents -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 0, q:z is 19:1 and the Mw (cf n) is 1500.

The following results were obtained: Base Viscosity Comparison Polymer Process mPa s at 21 s⊃min;¹ * Results are not reliable due to rapid phase separation.

Similar results could be obtained using similar polymers such as Polymer A3, A5 or A6.

Claims (8)

1. A liquid detergent composition comprising a dispersion of lamellar droplets of a detergent active in an aqueous continuous phase, the 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 the formula: wherein z is 1 and n is at least 1; (x+y) : z is 4 : 1 to 1000 : 1, wherein the monomer units may be in random order; R¹ represents -CO-O-, -O-, -O-CO-, -CH₂-, -CO-NH- or is absent; R² represents 1 to 50 independently selected alkyleneoxy groups or is absent, with the proviso that when R³ is absent, R⁴ represents hydrogen or contains not more than 4 carbon atoms, then R² must contain an alkyleneoxy group, preferably more than 5 alkyleneoxy groups having at least 3 carbon atoms; R³ represents a phenylene bond or is not present; R⁴ represents hydrogen or a C₁₋₂₄ alkyl or C₂₋₂₄ alkenyl group, with the proviso that when R² is not present, R⁴ is not hydrogen, and when also R³ is not present, then R⁴ must contain at least 5 carbon atoms; R⁵ represents hydrogen or a group of the formula -COOA⁴ ; R⁶ represents hydrogen or C₁₋₄alkyl; R⁸ and R⁹ represent -CH₂- or are absent; S¹ and S² 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, where t is 1-50 and where the monomer units can be in random order; and (IV) Polymers of the formula wherein: D represents -H or -OH and n is at least 1; wherein: A² represents A¹ or R¹⁰ respectively; Q¹ : Q² is 4 : 1 to 1000 : 1; R¹⁰ represents a C₅₋₂₄ alk(en)yl group; B represents -O-CO-R¹¹-CO-; R¹¹ represents -CH₂-, -C₂H₄-, -C₃H₆- or an aryl bond wherein the aryl bond is optionally substituted with one or more -COOA¹- groups or a benzophenone bond; A¹ is independently selected from hydrogen, alkali metals, alkaline earth metals, ammonium and amine bases and C₁₋₄ or (C₂H₄O)tH, where t is 1-50 and where the monomer units can be in random order; the polymer satisfies 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 biodegradability test of ¹⁴CO₂-labeled polymers; (f) Anaerobic batch testing of 14C-labeled polymers; (g) Continuous activated sludge simulation tests; and (h) Continuous activated sludge simulation test using radiolabelled polymers. 2. Liquid detergent according to claim 1, wherein the deflocculating polymer is a hydrophobically modified polysugar. 3. Liquid detergent according to claim 2, wherein the polysugar is a hydrophobically modified dextran, preferably with a molecular weight of 2000 to 20,000. 4. Liquid detergent according to claim 1 having a viscosity of less than 2500 mPas at 21 s⊃min;¹. 5. Liquid detergent according to claim 1, comprising 0.01 - 5 weight percent of deflocculant polymers. 6. Liquid detergent according to claim 1 with a pH value of 6 to 14. 7. Liquid detergent according to claim 1, comprising 1-70 weight percent detergent active ingredients. 8. A liquid detergent according to claim 1 which gives less than 10% by volume phase separation when stored at 25ºC for 21 days from the day of manufacture.