EP0697038B1

EP0697038B1 - Liquid detergent compostion

Info

Publication number: EP0697038B1
Application number: EP94915537A
Authority: EP
Inventors: Philippus Cornelis Van Der Hoeven; John Prescott
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 1993-05-04
Filing date: 1994-04-26
Publication date: 1997-07-16
Anticipated expiration: 2014-04-26
Also published as: JPH08509515A; ES2105711T3; DE69404298T2; WO1994025562A1; AU6721594A; EP0697038A1; ZA943038B; DE69404298D1

Abstract

Non-aqueous liquid detergent product compositions comprising a non-aqueous liquid phase and an ester of an acid and an alcohol to improve the gelling characteristics and/or reduces the viscosity of the liquid phase and/or to lower the solidification point of the non-aqueous liquid and/or that have low viscosity.

Description

TECHNICAL FIELD

The present invention relates to substantially non-aqueous liquid detergent compositions and to a process of preparing a non-aqueous liquid detergent composition. Non-aqueous liquids are those containing little or no free water.

PRIOR ART & BACKGROUND

Non-aqueous liquid detergent compositions are known in the art and have been described in quite a number of patent publications, e.g. in US-A-4,316,812, US-A-4,874,537 and EP-A-0,484,095. Non-aqueous liquids provide a way of concentrating liquid detergents still resulting in good washing performance.
Non-aqueous liquid detergent compositions normally comprise a non-aqueous liquid phase having incorporated therein as dispersion, solution or combination thereof, the usual detergent components and adjuncts depending on the purpose of use, primarily surfactants and builders.
The liquid phase often comprises a nonionic surfactant as major component, which apart from acting as carrier liquid for the detergent components, usually and preferably also has detergent-active properties, thereby acting wholly or in part as the surfactant ingredient.
One weakness of non-aqueous liquid detergent compositions is that on contact with water, they may show bad dispersibility as they tend to suffer from gelling. Such gelling problems have for example been described in GB-A-2,169,613 wherein alkylene glycol monoalkyl ethers are disclosed as anti-gelling agent. GB-A-2,168,995 describes acid-terminated nonionics and GB-A-2,177,716 dicarboxylic acids as gel-inhibition agents and other examples of anti-gelling compounds, such as lower aliphatic alcohols, glycols and polyethyleneglycol are described in EP-A-413,616.
Non-aqueous liquids may also suffer from high viscosity. This problem has for example been acknowledged in GB-A-2,200,366 in which the use of alkaline earth metal or zinc salt of fatty acids is suggested to increase pourability of the liquid.
Further, non-aqueous liquids may solidify upon storage, especially at low temperatures.
DD 120048 and DD120050 disclose homogeneous non-aqueous liquid compositions comprising a liquid phase and organic complexbuilders, that are esterified to make them soluble in the liquid phase, such as the tri-ethylester, the n-propylester, the trioctylester, the glycerine-ester and the polyglycolester of citric acid. The compositions do not comprise a solid dispersed particulate phase which restricts the use of ingredients to be used for the liquids to ingredients that are soluble in the liquid non-aqueous phase.
WO 93/06201 (EP-A-534,298) discloses the use of zeolite that is impregnated with a polar organic inerting agent in non-aqueous liquids. Examples of impregnating agents are esters of carboxylic acids with 1 to 3 carbon atoms and alcohols with 1 to 4 carbon atoms and acetic acid with a primary alcohol with 2 to 4 carbon atoms. The inerting agent is present in the solid phase and does not have another function than stabilising bleach against the zeolite surface.
EP-A-385,521 and EP-A-510762 disclose the use of alkyl (or fatty) carboxylic acid lower alkyl esters, as solvents in non-aqueous liquids. EP-A-510762 also discloses the use of glyceryl trialkylcarboxylates and glyceryl triacetate is given as an example.
It is however still desired to add ingredients to non-aqueous liquids in order to improve the dispersibility properties and/or to reduce the viscosity of the concentrated liquid phase and/or to lower the solidification point of the non-aqueous liquid.
It has now been found that non-aqueous liquid detergent compositions comprising a specific ester material can be formulated that show good dispersibility upon contact with water and/or that have good viscosity properties and/or have a low solidification point and/or have low viscosity.

SUMMARY OF THE INVENTION

Thus according to the invention there is provided a non-aqueous liquid detergent composition comprising a non-aqueous liquid phase and a specific ester.

DETAILED DESCRIPTION OF THE INVENTION

A preferred aspect of the invention is directed to inclusion of specific esters in non-aqueous liquids comprising a non-aqueous liquid phase, said esters meeting one or more of the following requirements:

1) pour point (see ASTM, American Standard Testing Method, D 97) of the ester is preferably less than 25°C, more preferably less than 15°C, most preferably less than 5°C and in particular less than 0°C;
2) the di-electric constant of the ester is preferably lower than 20, more preferably lower than 15, most preferably lower than 12, in particular lower than 10;
3) the degree of esterification of the hydroxyl groups of the alcohol is preferably more than 60%, more preferably more than 70% and most preferably more than 80% and in particular more than 90%;
4) the boiling point of the ester is preferably higher than 100°C;
5) the flash point of the ester is preferably higher than 90°C, more preferably higher than 100°C;
6) the boiling point of the alcohol is preferably higher than 75°C, more preferably higher than 90°C, most preferably higher than 100°C; and/or
7) the viscosity at ambient temperature (25°C) of the ester is preferably ≤40 mPa.s (=cP), more preferably <20 mPa.s and most preferably ≤10 mPa.s.

Suitable acid materials for preparation of the ester compound are C1 to C6 carboxylic acid and poly-carboxylic acid. The acid material may be saturated or unsaturated, straight or branched, cyclo-aliphatic or aliphatic. Preferably the acid material contains from C1 to C4 carbon atoms, more preferably C2 and/or C3. The most preferred carboxylic acids are acetic and propionic acid. Also mixtures of carboxylic acids may be used.
Examples of carboxylic acids are formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid and hexanoic acid. Examples of poly-carboxylic acid are succinic acid and citric acid.
Suitable alcohol materials used for the preparation of the ester are monohydric or polyhydric alcohols, such as dihydric, tri-hydric or tetra-hydric alcohols. Preferably the alcohol contains two or more hydroxyl groups. The alcohol may be selected from the following groups:

1) dihydric alcohols, such as ethylene glycol, propylene glycol, as well as polyethyleneglycol and polypropyleneglycol (both preferably containing 2 to 10, more preferably from 2 to 4 ethylene glycol groups) as well as their combination products with C2-C5 alkylene oxides. Preferably 2-10, more preferably 2-4 moles of alkylene oxide are used. Also mixtures of alkylene oxides and of the various alcohols may be used.
Preferred examples of dihydric alcohols are ethyleneglycol, diethyleneglycol, triethyleneglycol, propyleneglycol, dipropyleneglycol, tripropyleneglycol and 1,3 propane-diol;
2) ether alcohols containing C1 to C8 alcohol with 1 to 4 alkoxy groups, preferably C2 to C4 alcohol with 2 to 3 alkoxy groups. Preferably, the alkoxy groups are selected from ethoxy and/or propoxy groups.
Preferred examples of ether alcohols are diethylene glycol ethyl ether, diethylene glycol butyl ether and diethylene glycol hexyl ether; and
3) sterically hindered alcohols, selected from trimethylol propane, pentaerytritol, poly pentaerytritol, neopentyl glycol and mixtures thereof. Esters with chloride as a side-groups may also be used, although such compounds are not preferred for environmental reasons.

Group 1) represents the preferred group of alcohol for the preparation of the ester.
Ethyleneglycol may be esterified with one carboxylic acid, but preferably ethyleneglycol is esterified with two carboxylic acids. An examples of an ethyleneglycol ester is ethylene glycol di-acetate.
Polyethyleneglycol can be esterified with one carboxylic, but preferably polyethyleneglycol is esterified with two carboxylic acids. Examples of polyethyleneglycol esters are PEG 200 and PEG 400 that are "capped" with formic, acetic, propionic acid or mixtures thereof.
Propyleneglycol can be esterified with one carboxylic acid, but preferably propyleneglycol is esterified with two carboxylic acids. Examples of propyleneglycol esters are propyleneglycol diacetate, propylene glycol dipropionate, and mixtures of acetate and propionate.
Polypropyleneglycol can be esterified with one carboxylic acid, but preferably polypropyleneglycol is esterified with two carboxylic acids. An example of an ester of polypropyleneglycol is polypropyleneglycol di-acetate.
The degree of esterification of the hydroxyl groups of the ether alcohols is preferably more than 60%, and they contain for example no free carboxylic groups. Preferably they are esterified with C1-C6 alkyl mono carboxylic acid. Examples of esters of ether alcohols are acetate or propionate esters of diethylene glycol hexyl ether, of diethylene glycol ethyl ether or of diethylene glycol butyl ether.
The sterically hindered alcohols are preferably esterified with acetic and/or propionic acid.
The most preferred esters are propylene glycol diacetate, tri-ethylene glycol diacetate, di-ethylene glycol diacetate and di esters of acetate and propane-1,3-diol.
By weight of the liquid phase, generally the ester is present in amounts of 0.01% or higher, preferably at least 0.1%, more preferably at least 1% by weight and generally in amounts of at most 50%, preferably at most 40%, more preferably at most 30%, most preferably 20% by weight, particularly preferred at most 10%.
Thus it will be clear that contrary to WO 93/06201 (equivalent to EP-A-534,298) the ester of the present invention is present in the liquid phase (e.g. at least for 90% by weight), whereas the impregnating agent of WO 93/06201 is present in the solid phase.
By weight of the composition, generally the ester is present in amounts of 0.01% or higher, preferably at least 0.1%, more preferably at least 1% and generally at most 40%, preferably at most 35%, more preferably at most 30%, most preferably at most 20% and particularly preferred at most 10%.
Preferably the non-aqueous liquid phase of the non-aqueous liquid detergent composition comprises the ester according to the invention as well as a nonionic surfactant material in weight ratio of from 2:1 to 1:30, more preferably from 1:1 to 1:10, most preferably from 1:2 to 1:5.

PRODUCT FORM

All compositions according to the present invention are liquid cleaning products. In the context of this specification, all references to liquid cleaning products refer to those product materials which are liquid or in a paste form, preferably liquid at 25°C at atmospheric pressure. They may be formulated in a very wide range of specific forms, according to the intended use. They may be formulated as cleaners for hard surfaces (with or without abrasive) or as agents for warewashing (cleaning of dishes, cutlery, etc) either by hand or mechanical means, as well as in the form of specialised cleaning products, such as for surgical apparatus or artificial dentures. Preferably compositions of the invention are formulated as agents for washing and/or conditioning of fabrics.
Thus, the compositions will contain at least one agent which promotes the cleaning and/or conditioning of the article(s) in question, selected according to the intended application. Usually, this agent will be selected from surfactants, enzymes, bleaches, builders, buffers, microbiocides, (for fabrics) fabric softening agents and (in the case of hard surface cleaning) abrasives. Of course in many cases, more than one of these agents will be present, as well as other ingredients commonly used in the relevant product form.
If compositions of the invention are fabric cleaning products they preferably contain a liquid phase containing nonionic surfactants and a solid phase dispersed in the liquid phase, said solid phase comprising one or more of the following ingredients: bleaches, bleach activators, builders, abrasives and solid surfactants. If compositions of the invention are intended for other uses, for example for mechanical warewashing, sometimes the liquid phase will comprise an additional solvent material other than nonionic surfactant such as for example paraffin, a low molecular weight polyethylene glycol or an ethoxylated polyethylene glycol. The solid phase of the product will then generally comprise one or more of builders, abrasive materials and solid surfactant materials.

SURFACTANT

Where surfactants are solids, they will usually be dissolved or dispersed in the liquid phase. Where they are liquids, they will usually constitute all or part of the liquid phase. However, in some cases the surfactants may undergo a phase change in the composition.
In general, surfactants for use in the compositions of the invention 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.

NON-IONIC SURFACTANTS

Nonionic detergent surfactants are well-known in the art. They normally consist of a hydrophilic polyalkoxylene or a mono- or di-alkanolamide group in chemical combination with an organic hydrophobic group derived, for example, from (poly)alkylphenols in which the alkyl group contains from about 6 to about 12 carbon atoms; primary, secondary or tertiary aliphatic alcohols (or alkyl-capped derivatives thereof), preferably having from 8 to 20 carbon atoms; monocarboxylic acids having from 10 to about 24 carbon atoms in the alkyl group and polyoxypropylenes. Also common are fatty acid mono- and dialkanolamides in which the alkyl group of the fatty acid radical contains from 10 to about 20 carbon atoms and the alkyloyl group having from 1 to 3 carbon atoms. In any of the mono- and di-alkanolamide derivatives, optionally, there may be a polyoxyalkylene moiety joining the latter groups and the hydrophobic part of the molecule. In all polyalkoxylene containing surfactants, the polyalkoxylene moiety preferably consists of an average of from 2 to 20 groups of ethylene oxide and/or propylene oxide groups. Amongst the latter class, particularly preferred are those described in EP-A-225,654, especially for use as all or part of the liquid phase. Also preferred are those ethoxylated nonionics which are the condensation products of fatty alcohols with from 9 to 15 carbon atoms condensed with from 3 to 11 moles of ethylene oxide. Examples of these are the condensation products of C11-13 alcohols with 3 to 7 moles of ethylene oxide. These may be used as the sole nonionic surfactants or in combination with those as described in EP-A-225,654, especially as all or part of the liquid phase.
Another class of suitable nonionics comprise the alkyl polysaccharides (polyglycosides/oligosaccharides) such as described in any of specifications US-A-3,640,998; US-A-3,346,558; US-A-4,223,129; EP-A-92,355; EP-A-99,183; EP-A-70,074, EP-A-70,075, EP-A-70,076, EP-A-70,077; EP-A-75,994, EP-A-75,995 and EP-A-75,996.
Mixtures of different nonionic detergent surfactants may also be used. Especially preferred is the combined use of detergency nonionics (e.g. alkoxylated fatty alcohols containing 5-10 EO) with non-detergency nonionics (e.g. alkoxylated alcohols containing 2-4 EO groups).
Mixtures of nonionic detergent surfactants with other detergent surfactants such as anionic, cationic or ampholytic detergent surfactants and soaps may also be used.
Preferably the level of nonionic surfactants in the composition is from 1 to 90 % by weight of the composition, more preferably 5 to 75 %, most preferably 20 to 60 %.

ANIONIC SURFACTANTS

Examples of suitable anionic detergent surfactants are alkali metal, ammonium or alkylolamine salts of alkylbenzene sulphonates or primary alkyl sulphates having from 10 to 18 carbon atoms in the alkyl group, alkyl and alkylether sulphates having from 10 to 24 carbon atoms in the alkyl group, the alkylether sulphates having from 1 to 5 ethylene oxide groups, and olefin sulphonates prepared by sulphonation of C10-24 alpha-olefins and subsequent neutralization and hydrolysis of the sulphonation reaction product and all stable free acid forms of such anionic surfactants.
Compositions of the invention comprise a solid phase dispersed in the liquid phase. As used herein, the term "solids" is to be construed as referring to materials in the solid phase which are added to the composition and are dispersed therein in solid form, those solids which dissolve in the liquid phase and those in the liquid phase which solidify (undergo a phase change) in the composition, wherein they are then dispersed.

THE NON-AQUEOUS ORGANIC SOLVENT

As a general rule, the most suitable liquids to choose as the liquid phase are those organic materials having polar molecules. In particular, those comprising a relatively lipophilic part and a relatively hydrophilic part, especially a hydrophilic part rich in electron lone pairs, tend to be well suited. This is completely in accordance with the observation that liquid surfactants, especially polyalkoxylated nonionics, are one preferred class of material for the liquid phase.
Additional non-surfactants which are suitable for use as the liquid phase include those having the preferred molecular forms referred to above although other kinds may be used, especially if combined with those of the former, more preferred types. In general, the non-surfactant solvents can be used alone or in combination with liquid surfactants. Non-surfactant solvents which have molecular structures which fall into the former, more preferred category include ethers, polyethers, alkylamines and fatty amines, (especially di- and tri-alkyl- and/or fatty-N-substituted amines), alkyl (or fatty) amides and mono- and di-N-alkyl substituted derivatives thereof, ketones, aldehydes, and glycerides. Specific examples include respectively, di-alkyl ethers, polyethylene glycols, alkyl ketones (such as acetone), glycerol, propylene glycol, and sorbitol.
Many light solvents with little or no hydrophilic character are in most systems, to a small extent, unsuitable on their own. Examples of these are lower alcohols, such as ethanol, or higher alcohols, such as dodecanol, as well as alkanes and olefins. However, they can be combined with other liquid materials.

PROPORTION OF LIQUID PHASE

Preferably, the compositions of the invention contain the liquid phase (whether or not comprising liquid surfactant) in an amount of at least 10% by weight of the total composition. The amount of the liquid phase present in the composition may be as high as about 100%, preferably about 90%, but in most cases the practical amount will be between 20 and 70% and preferably between 35 and 60% by weight of the composition.

SOLIDS CONTENT

If present, in general the solids content of the product may be within a very wide range, for example from 10-90%, usually from 30-80% and preferably from 40-65% by weight of the final composition. The solid phase should be in particulate form and have a weight average particle size of less than 300 microns, preferably less than 200 microns, more preferably less than 100 microns, especially less than 10 microns. The particle size may even be of sub-micron size. The proper particle size can be obtained by using materials of the appropriate size or by milling the total product in a suitable milling apparatus. In order to control aggregation of the solid phase leading to irreversible settling or setting of the composition, it is preferred to include a deflocculant therein.

OTHER INGREDIENTS

In addition to the components already discussed, there are many other ingredients which can be incorporated in liquid cleaning products. There is a very great range of such other ingredients and these will be choosen according to the intended use of the product. However, the greatest diversity is found in products for fabrics washing and/or conditioning. Many ingredients intended for that purpose will also find application in products for other applications (e.g. in hard surface cleaners and warewashing liquids).

HYDROPHOBICALLY MODIFIED MATERIALS

The physical stability of non-aqueous liquid detergent compositions can be even further improved and/or setting problems can be minimised, if hydrophobically modified dispersants (hereinafter termed HM materials) are used. For the purpose of the present invention, a dispersant material is a material, of which the main purpose is to stabilise the composition. HM materials are particulate materials, of which the outer surface has chemically been treated to reduce the hydrophillic nature thereof.
Preferred HM materials have a weight average particle size of from 0.005 to 5 micrometers, more preferred 0.01 to 3 micrometers, most preferred from 0.02 to 0.5 micrometer. The amount of the HM material is preferably from 0.1 to 10 % by weight of the composition, more preferred 0.3 to 5 %, most preferred from 0.5 to 3 % by weight.
Preferably the number of hydroxyl and/or carboxyl groups at the surface of the particles is reduced by the hydrophobic modification treatment. Suitable reactions include esterification or etherification of the hydrophilic groups. Preferably the hydrophobic modification treatment involves at least 10 % of the hydrophilic groups at the surface of the particle, more preferably from 40 to 95 %, most preferably from 50 to 90 %. Partial hydrophobing is preferred over complete hydrophobic modification.
Preferably HM silica containing dispersants are used. The hydrophobic modification of the silica particles preferably involves the substitution of the free hydroxyl groups at the outer surface of the silica particles by a short alkyl or silyl group. More preferably the surface hydroxyl groups are substituted by methyl groups.
For even greater reduction the clear layer separation of liquid detergent compositions of the invention, it has been found that the use of particulate metal oxides is especially advantageous. Preferred suspended metal oxides have a bulk density of 200 to 1,000 g/l, more preferred 250 to 800 g/l, especially preferably 300 to 700 g/l, most preferably from 400 to 650 g/l.
Preferably, the metal oxide is selected from calcium oxide, magnesium oxide and aluminium oxide, most preferably magnesium oxide is used.
The weight average particle size of the metal oxide is preferably from 0.1 to 200 micrometers, more preferably from 0.5 to 100 micrometers, most preferably from 2 to 70 micrometers. The level of metal oxide is preferably from 0.1 to 7 % by weight of the composition, more preferably from 0.5 to 5 %, most preferably from 1 to 4 %.

DETERGENCY BUILDERS

The detergency builders are those materials which counteract the effects of water hardness, either by precipitation or by an ion sequestering effect. They comprise both inorganic and organic builders. They may also be sub-divided into the phosphorus-containing and non-phosphorus types, the latter being preferred when environmental considerations are important.
In general, the inorganic builders comprise the various phosphate-, carbonate-, silicate-, borate- and aluminosilicate-type materials, particularly the alkali-metal salt forms. Mixtures of these may also be used.
Examples of phosphorus-containing inorganic builders, when present, include the water-soluble salts, especially alkali metal pyrophosphates, orthophosphates, polyphosphates and phosphonates. Specific examples of inorganic phosphate builders include sodium and potassium tripolyphosphates, phosphates and hexametaphosphates.
Examples of non-phosphorus-containing inorganic builders, when present, include water-soluble alkali metal carbonates, bicarbonates, borates, silicates, metasilicates, and crystalline and amorphous aluminosilicates. Specific examples include sodium carbonate (with or without calcite seeds), potassium carbonate, sodium and potassium bicarbonates, silicates and zeolites.
Examples of organic builders include the alkali metal, ammonium and substituted ammonium, citrates, succinates, malonates, fatty acid sulphonates, carboxymethoxy succinates, polyacetates, carboxylates, polycarboxylates, aminopolycarboxylates, polyacetyl carboxylates and polyhydroxysulphonates. Specific examples include sodium, potassium, lithium, ammonium and substituted ammonium salts of ethylenediaminetetraacetic acid, nitrilotriacetic acid, oxydisuccinic acid, mellitic acid, benzenepolycarboxylic acids and citric acid. Other examples are organic phosphonate type sequestering agents such as those sold by Monsanto under the tradename of Dequest.
Other suitable organic builders include the higher molecular weight polymers and copolymers known to have builder properties, for example appropriate polyacrylic acid, polymaleic acid and acrylic/maleic acid copolymers and their salts, such as those sold by BASF under the Sokalan Trade Mark. Preferably the level of builder materials is from 0-60%, more preferred 5-50%, most preferred 10-40% by weight of the composition.

THE DEFLOCCULANT

Preferably compositions of the invention also comprise one or more deflocculant materials. In principle, any material may be used as a deflocculant provided it fulfils the deflocculation test and is selected from the groups as described in European Patent Specification EP-A-266 199 (Unilever). The content of this specification is hereby incorporated by reference and in particular the definition of the deflocculant. The capability of a substance to act as a deflocculant will partly depend on the solids/liquid phase combination. However, it is especially preferred to add the deflocculant as acid.
Some typical examples of deflocculants include the alkanoic acids such as formic, acetic, propionic and stearic acids and their halogenated derivatives such as trichloracetic and trifluoracetic as well as the alkyl (e.g. methane) sulphonic acids and aralkyl (e.g. paratoluene) sulphonic acids.
Examples of suitable inorganic mineral acids and their salts are hydrochloric, carbonic, sulphurous, sulphuric and phosphoric acids; potassium monohydrogen sulphate, sodium monohydrogen sulphate, potassium monohydrogen phosphate, potassium dihydrogen phosphate, sodium monohydrogen phosphate, potassium dihydrogen pyrophosphate, tetrasodium monohydrogen triphosphate.
Other organic acids may also be used as deflocculants, for example formic, lactic, amino acetic, benzoic, salicylic, phthalic, nicotinic, ascorbic, ethylenediamine tetraacetic, and aminophosphonic acids, as well as longer chain fatty acids, such as oleic, stearic, lauric acid and the like. Peracids such as percarboxylic and persulphonic acids may also be used.
The class of acid deflocculants further extends to the Lewis acids, including the anhydrides of inorganic and organic acids. Examples of these are acetic anhydride, maleic anhydride, phthalic anhydride, succinic anhydride and diphosphorous pentoxide.
"Fatty" anions are very suitable deflocculants, and a particularly preferred class of deflocculants comprises anionic surfactants. Although anionics, which are salts of alkali or other metals may be used, particularly preferred are the free acid forms of these surfactants. These anionic surfactants include all those classes, sub-classes and specific forms described in the aforementioned general references on surfactants, viz, Schwartz & Perry, Schwartz Perry and Berch, McCutcheon's, Tensid-Taschenbuch; and the free acid forms of such surfactants. Many anionic surfactants have already been described hereinbefore.
In particular, some preferred sub-classes and examples are the C10-C22 fatty acids and polymers thereof, the C8-C18 alkylbenzene sulphonic acids, the C10-C18 alkyl or alkylether sulphuric acid monoesters, the C12-C18 paraffin sulphonic acids, the fatty acid sulphonic acids, the benzene-, toluene-, xylene- and cumene sulphonic acids and so on. Particularly preferred are the linear C12-C18 alkylbenzene sulphonic acids.
also zwitterionic-types can also be used as deflocculants. These may be any described in the aforementioned general surfactant references. one example is lecithin.
The level of the deflocculant material in the composition can be optimised by the means described in the aforementioned EP-A-266 199, but in very many cases is at least 0.01%, usually 0.1% and preferably at least 1% by weight, and may be as high as 15% by weight. For most practical purposes, the amount ranges from 2-12%, preferably from 4-10% by weight, based on the final composition. Surprisingly, however it has been found that for obtaining stability, in compositions of the invention generally the presence of the polymer material reduces the need for high levels of deflocculant material.

THE BLEACH SYSTEM

Bleaches include the halogen, particularly chlorine bleaches such as are provided in the form of alkali metal hypohalites, e.g. hypochlorites. In the application of fabrics washing, the oxygen bleaches are preferred, for example in the form of an inorganic persalt, preferably with a bleach precursor, or as a peroxy acid compound.
In the case of the inorganic persalt bleaches, the activator makes the bleaching more effective at lower temperatures, i.e. in the range from ambient temperature to about 60°C, so that such bleach systems are commonly known as low-temperature bleach systems and are well-known in the art. The inorganic persalt such as sodium perborate, both the monohydrate and the tetrahydrate, acts to release active oxygen in solution, and the activator is usually an organic compound having one or more reactive acyl residues, which cause the formation of peracids, the latter providing for a more effective bleaching action at lower temperatures than the peroxybleach compound alone. The ratio by weight of the peroxybleach compound to the activator is from about 20:1 to about 2:1, preferably from about 10:1 to about 3.5:1. Whilst the amount of the bleach system, i.e. peroxybleach compound and activator, may be varied between about 5% and about 35% by weight of the total liquid, it is preferred to use from about 6% to about 30% of the ingredients forming the bleach system. Thus, the preferred level of the peroxybleach compound in the composition is between about 5.5% and about 27% by weight, while the preferred level of the activator is between about 0.5% and about 14%, most preferably between about 1% and about 7% by weight.
Typical examples of the suitable peroxybleach compounds are alkalimetal perborates, both tetrahydrates and monohydrates, alkali metal percarbonates, persilicates and perphosphates, of which sodium perborate is preferred.
It is particularly preferred to include in the compositions, a stabiliser for the bleach or bleach system, for example ethylene diamine tetramethylene phosphonate and diethylene triamine pentamethylene phosphonate or other appropriate organic phosphonate or salt thereof, such as the Dequest range hereinbefore described. These stabilisers can be used in acid or salt form, such as the calcium, magnesium, zinc or aluminium salt form. The stabiliser may be present at a level of up to about 1% by weight, preferably between about 0.1% and about 0.5% by weight of the composition.
The applicants have also found that liquid bleach precursors, such as glycerol triacetate and ethylidene heptanoate acetate, isopropenyl acetate and the like, also function suitably as a material for the liquid phase, thus obviating or reducing any need of additional relatively volatile solvents, such as the lower alkanols, paraffins, glycols and glycolethers and the like, e.g. for viscosity control.

MISCELLANEOUS OTHER INGREDIENTS

Other ingredients comprise those remaining ingredients which may be used in liquid cleaning products, such as fabric conditioning agents, enzymes, perfumes (including deoperfumes), micro-biocides, colouring agents, fluorescers, soil-suspending agents (anti-redeposition agents), corrosion inhibitors, enzyme stabilising agents, and lather depressants.
Amongst the fabric conditioning agents which may be used, either in fabric washing liquids or in rinse conditioners, are fabric softening materials such as fabric softening clays, quaternary ammonium salts, imidazolinium salts, fatty amines and cellulases. Enzymes which can be used in liquids according to the present invention include proteolytic enzymes, amylolytic enzymes and lipolytic enzymes (lipases). Various types of proteolytic enzymes and amylolytic enzymes are known in the art and are commercially available. They may be incorporated as "prills", "marumes" or suspensions.
The fluorescent agents which can be used in the liquid cleaning products according to the invention are well known and many such fluorescent agents are available commercially. Usually, these fluorescent agents are supplied and used in the form of their alkali metal salts, for example, the sodium salts. The total amount of the fluorescent agent or agents used in a detergent composition is generally from 0.02-2% by weight of the composition.
When it is desired to include anti-redeposition agents in the liquid cleaning products, the amount thereof is normally from about 0.1% to about 5% by weight, preferably from about 0.2% to about 2.5% by weight of the total liquid composition. Preferred anti-redeposition agents include carboxy derivatives of sugars and celluloses, e.g. sodium carboxymethyl cellulose, anionic polyelectrolytes, especially polymeric aliphatic carboxylates, or organic phosphonates.

WATER

The compositions are substantially non-aqueous, i.e. they contain little or no free water, preferably no more than 5%, preferably less than 3%, especially less than 1% by weight of the total composition. It has been found that the higher the water content, the more likely it is for the viscosity to be too high, or even for setting to occur.

USE

The composition in accordance with the present invention may be used for several detergency purposes, for example the cleaning of surfaces and the washing of fabrics. For the washing of fabrics, preferably an aqueous liquor containing 0.1 to 10 %, more preferably 0.2 to 2%, of the non-aqueous detergent composition of the invention is used.

PROCESSING

During manufacture, it is preferred that all raw materials should be dry and (in the case of hydratable salts) in a low hydration state, e.g. anhydrous phosphate builder, sodium perborate monohydrate and dry calcite abrasive, where these are employed in the composition.
In a preferred process, the dry, substantially anhydrous solids are blended with the liquid phase in a dry vessel. If deflocculant materials are used, these should preferably -at least partly- be mixed with the liquid phase, prior to the addition of the solids. In order to minimise the rate of sedimentation of the solids, this blend is passed through a grinding mill or a combination of mills, e.g. a colloid mill, a corundum disc mill, a horizontal or vertical agitated ball mill, to achieve a particle size of 0.1 to 100 microns, preferably 0.5 to 50 microns, ideally 1 to 10 microns. A preferred combination of such mills is a colloid mill followed by a horizontal ball mill since these can be operated under the conditions required to provide a narrow size distribution in the final product. Of course particulate material already having the desired particle size need not be subjected to this procedure and if desired, can be incorporated during a later stage of processing.
During this milling procedure, the energy input results in a temperature rise in the product and the liberation of air entrapped in or between the particles of the solid ingredients. It is therefore highly desirable to mix any heat sensitive ingredients into the product after the milling stage and a subsequent cooling step. It may also be desirable to de-aerate the product before addition of these (usually minor) ingredients and optionally, at any other stage of the process. Typical ingredients which might be added at this stage are perfumes and enzymes, but might also include highly temperature sensitive bleach components or volatile solvent components which may be desirable in the final composition. However, it is especially preferred that volatile material be introduced after any step of de-aeration. Suitable equipment for cooling (e.g. heat exchangers) and de-aeration will be known to those skilled in the art.
We have found that a preferred process of preparing non-aqueous liquid detergent compositions, which consists of adding at least some of the ester used in the present invention after the non-aqueous liquid with the solid particles is milled. Surprisingly, this makes the milling process more efficient as smaller solid particles result in less time, consuming less energy.
Therefore, a further embodiment of the present invention relates to a process of preparing a non-aqueous liquid detergent composition comprising a non-aqueous liquid phase and a solid particulate phase dispersed in the non-aqueous liquid phase, wherein the non-aqueous liquid phase further comprises an ester of a C1-6 carboxylic acid or poly-carboxylic acid and an alcohol, wherein the solid particulate phase is milled and at least 25% by weight of the ester is added after the milling.
Preferably, at least 40% by weight of the total of the ester is added after the milling step, preferably at least 50%, more preferably at least 75%. most preferably at least 90% by weight.
It follows that all equipment used in this process should preferably be completely dry, special care being taken after any cleaning operations. The same is true for subsequent storage and packing equipment.

EXAMPLES

A standard non-aqueous liquid detergent composition comprising a non-aqueous liquid phase and suspended particles was prepared by using by weight of (the final composition, i.e. including the ester of) a carbonate/calcite builder system (29.0%), a sodium perborate bleach system (11.5%), a structurant (Sipernat D17) (3.0%), a number of minor ingredients, i.e. polymeric anti-redeposition agent, optical whitener, a blend of enzymes (Lipase, Protease and Amylase), perfumes, silicone oil based antifoam (in total: 4.7%), an anionic surfactant dispersant (LAS acid) (6.0%) and a blend of nonionics C10-12EO7/E3 (35.8%).
After preparation of the liquid (including milling the composition to reduce the size of the solid particles, an extra 10% by weight of (the final composition, i.e. including the ester), an ester employed in the present invention was added to the composition and the dispersibility (of concentrate and dilute), the dissolution rate and the product viscosity were measured. The results are shown in the Table.
Dispersibility of a concentrated mixture of product and water, in the weight ratio 4:1, was determined and expressed in terms of stirrability of 8 ml of mixture (=10g) by a magnetic stirrer in a 100 ml beaker. Dispersibility was judged on a five point scale: 0 = very easy, 0.5 = easy, 1 = moderate, 1.5 = hardly and 2 = non dispersible.
Dispersibility of a diluted mixture of product and water, in the weight ratio of 1:2, was determined and expressed in terms of stirrability of 8 ml of product (=10g) by a magnetic stirrer in a 100 ml beaker. The dispersibility is judged on a five point scale: 0 = very easy, 0.5 = easy, 1 = moderate, 1.5 = hardly and 2 = non dispersible.

The dissolution rate was determined by stirring, with a rate of 300 rpm with a magnetic stirrer, 10 g of product in a 100 ml beaker with 2.5 liter tapwater (final conc. 4 g/l) and determining the weight % dissolved after 5 minutes at room temperature (25°C).

Extra 10% added to product composite:	Dispersibility of concentrate	Dispersibility of dilute	Dissolution rate (% dissolved after 5 minutes)	Product viscosity in Pas 21s ^-1
Original nonionic blend (= blanc)	1	2	45	1.08
Propylene-Glycol-Di-Acetate	1	0.5	80	0.98
Propane-Diol-Di-Acetate	1	1	>70	1
Propylene-Glycol-Di-Propionate	2	0	65	0.89
Ethylene-Glycol-Di-Acetate	0.5	1	85	1.09
Di-Ethylene-Glycol-Di-Acetate	1	0.5	70	1.04
Tri-Ethylene-Glycol-Di-Acetate	1	0.5	90	1.10
2-Butoxy-Ethylene-Glycol-Mono-Acetate (ether-ester)	1.5	1.5	50	1.11

Claims

Non-aqueous liquid detergent composition comprising a non-aqueous liquid phase and an ester of a C1-6 carboxylic acid and/or poly-carboxylic acid and an alcohol selected from dihydric alcohols, ether C_1-8 alcohols with 1-4 alkoxy groups and sterically hindered alcohols, selected from trimethylol propane, pentaerytritol, polypentaerytritol, neopentyl glycol and mixtures thereof.
Composition according to claim 1, wherein the dihydric alcohol is selected from ethylene glycol, polyethyleneglycol, propylene glycol, polypropyleneglycol and mixtures thereof.
Composition according to claim 1, wherein the alcohol is an ether alcohol selected from diethylene glycol ethyl ether, diethylene glycol butyl ether and diethylene glycol hexyl ether.
Composition according to claims 1-3, wherein the carboxylic acid or poly-carboxylic acid contains from 2 to 3 carbon atoms.
Composition according to claims 1-4, wherein the alcohol has a degree of esterification of the hydroxy groups of more than 60%.
Composition according to claims 1-5, wherein the ester is present in amounts of from 0.01 to 50% by weight of the composition.
Composition according to claims 1-6 further comprising a solid particulate phase dispersed in the non-aqueous liquid phase.
Process of preparing a non-aqueous liquid detergent composition comprising a non-aqueous liquid phase and a solid particulate phase dispersed in the non-aqueous liquid phase, wherein the non-aqueous liquid phase comprises an ester of a C1-6 carboxylic acid or poly-carboxylic acid and an alcohol, wherein the solid particulate phase is milled and at least 25% by weight of the total amount of ester is added after the milling.