WO2004111177A1

WO2004111177A1 - Detergent component and process for its preparation

Info

Publication number: WO2004111177A1
Application number: PCT/EP2004/005131
Authority: WO
Inventors: Harmannus Tammes; Remy Antal Verburgh
Original assignee: Unilever Plc; Unilever Nv; Hindustan Lever Limited
Priority date: 2003-06-06
Filing date: 2004-05-12
Publication date: 2004-12-23
Also published as: GB0313139D0

Abstract

A process for the preparation of a particulate detergent component comprising an organic gelling agent, which process comprises absorbing a liquid detergent ingredient, which is an aqueous solution, dispersion or emulsion of detergent ingredient, into the gelling agent and removing water by an evaporative process.

Description

DETERGENT COMPONENT AND PROCESS FOR ITS PREPARATION

TECHNICAL FIELD

The present invention relates to a granular detergent component suitable for incorporation into particulate laundry detergent compositions, and a novel process for its preparation..

BACKGROUND AND PRIOR ART

Many detergent ingredients are available in liquid form. This can be for a variety of reasons, for example storage stability.

Detergent surfactants may be available as solids, but in many cases are commercially available only as solutions, generally aqueous solutions of relatively low concentration, typically below 50 wt%, for example, 30 to 40 wt%. For some materials, for example, water-soluble quaternary ammonium cationic surfactants having a single long hydrocarbon chain or branched, especially mid-chain branched anionic surfactants, mobile solutions of higher concentration are not obtainable because gelling occurs. Similarly, complete drying is not effective because the compounds either form sticky solids which are not suitable for handling and processing and/or decompose at the temperatures necessary for effective drying.

Additionally many polymers are available as aqueous solutions and some ingredients are available as emulsions. While these materials may be suitable for inclusion in liquid detergent compositions, or for incorporation in detergent powders via traditional slurry-making and spray- drying processes, the large amount of associated water can pose problems in preparing granular detergent compositions or components by non-spray-drying (mixing and granulation) processes .

WO 96/17042A (Procter & Gamble) discloses detergent granules containing a .water-soluble cationic surfactant and an inorganic carrier, the granules also containing an anionic surfactant in a weight ratio to the cationic surfactant of less than 1:1, and preferably less than 0.5:1. The inorganic carrier material is zeolite. The granules are prepared by evaporating and concentrating a solution of the cationic and anionic surfactants to a concentration above 50 wt%, and then granulating with the carrier material. The presence of the anionic surfactant prevents gelling during the concentration step.

WO 98/53037A (Procter & Gamble) discloses a process for the preparation of cationic surfactant granules, in which a aqueous solution or dispersion of cationic surfactant, optionally plus sodium silicate and/or filler, is dried in the presence of a drying gas, preferably air, at a temperature of less than 250⁰C. The preferred drying method is co-current spray-drying.

The present inventors have now discovered a particularly convenient process for manufacturing detergent components which are made up of liquid ingredients. The invention accordingly provides a process for the preparation of a particulate detergent component comprising an organic gelling agent, which process comprises absorbing an aqueous solution, dispersion or emulsion of detergent ingredient into the gelling agent and removing water by an evaporative process.

In a second aspect, the present invention provides a detergent component comprising an organic gelling agent.

It has been found that the advantages of the present invention are greatly reduced or lost altogether if the mixture of an aqueous solution, dispersion or emulsion of detergent ingredient and organic gelling agent is dried at too high a temperature. Without being bound by theory, it is believed that higher temperatures denature the organic gelling agent and reduce its capacity to bind the liquid detergent ingredient and form a solid detergent component. The exact temperature limit will be determined by the gelling agent and, by the liquid detergent being used and is easily determined by simple small scale experiment.

It has been found that the problems of high temperature drying can be greatly reduced or eliminated by drying the mixture of liquid detergent ingredient and gelling agent along with an insoluble carrier powder. Preferably this carrier comprises a material, such as a detergency builder, which would subsequently be added to a finished detergent mixture. By using a mixture of liquid detergent ingredient and gelling agent the liquid detergent ingredient content of the powder or granules produced can be made higher than when using carrier and liquid detergent ingredient alone.

DETAILED DESCRIPTION OF INVENTION

The Process

The solution of liquid detergent ingredient and organic gelling agent and carrier powder may be brought together by any convenient means. Preferably, the solution is added to a carrier powder in a high, medium or low shear mixer. Most preferably the aqueous solution, dispersion or emulsion is sprayed on to a carrier powder as it is agitated. The carrier powder may conveniently be granulated during this process.

In a preferred process the carrier powder, optionally along with other powders, is fluidised in a fluid bed reactor and the surfactant solution sprayed on to or in to the fluid bed. A granular material is formed which may subsequently be dried in the fluid bed or externally. In another preferred process some or all of the surfactant solution is added to the carrier powder, optionally along with other powders, in a high or medium shear mixer or a flash before being passed into a fluid bed reactor for addition of extra surfactant solution, if required, and drying.

As outlined above, the process of the present invention comprises dissolving an organic gelling agent in an aqueous solution, dispersion or emulsion of detergent ingredient and drying to produce a solid powder. The gelling agent may be added in any convenient form. Preferably, it will be added as a dry solid since this minimises the amount of water to be evaporated. However, it may be added as an aqueous solution or as a non aqueous solution, provided the solvent is miscible with water and compatible with the detergent ingredient . The amount to be added can be easily determined by simple experiment but will preferably be in the range of 1% to 20% dry weight of gelling agent to dry weight of detergent ingredient, more preferably in the range 2% - 10% and most preferably in the range 4% - 6%.

A low temperature drying process is preferably used when the detergent component contains only surfactant and organic gelling agent. A number of suitable techniques are well known to those skilled in the art including freeze drying, vacuum evaporation and low relative humidity drying.

When a third component is used, the liquid detergent ingredient and a carrier powder may be brought together by any convenient means. Preferably, the aqueous solution, dispersion or emulsion of detergent ingredient is added to the carrier powder in a high, medium or low shear mixer. Most preferably the aqueous solution, dispersion or emulsion of detergent ingredient is sprayed on to the carrier powder as it is agitated. The solution/carrier mix may be in the form of a damp powder or a slurry and appropriate solutions are known to those skilled in the art to handle such materials. An important feature is that temperature must be kept below the level at which the advantages of the invention are lost. Typically this will be achieved at below 80⁰C. - S -

The Mixers

Appropriate mixers for this process include the high-shear p

Lodige CB machine or moderate-speed mixers such as a Lodige KM machine. Other suitable equipment includes Drais^R

T160 series manufactured by Drais Werke GmbH, Germany; the Littleford mixer with internal chopping blades and turbine- type miller mixer having several blades on an axis of rotation. A low- or high-shear mixer granulator has a stirring action and/or a cutting action which are operated independently of one another. Preferred types of low- or high-shear mixer granulators are mixers of the Fukae^R FS-G series; Diosna V series ex Dierks & Sohne, Germany; Pharma

Matrix ex. T. K. Fielder Ltd, England. Other mixers believed to be suitable for use in the process of the p invention are Fuji VG-C series ex Fuji Sangyo Co., Japan; the Roto ex Zanchetta & Co. srl , Italy and Schugi^R Flexomix granulator.

Yet another suitable mixer is the Lodige (Trade Mark) FM series (ploughshare mixers) batch mixer ex Morton Machine Col Ltd. , Scotland.

The low shear mixer may conveniently comprise a gas fluidisation granulator, preferably operated at a superficial air velocity of about 0.1-1.2 ms , either under positive or negative relative pressure and with an air inlet temperature ranging from -10° or 5°C up to 30°C with an optional step at up to 80 °C, or in some cases, up to 200 °C. An operational temperature inside the bed of from ambient temperature to 60⁰C is typical.

In a preferred process the droplet size in the spray relative to the particle size of the solids is adjusted to control granule size, bulk density and the yield of the process. The process comprises spraying droplets of the surfactant solution containing organic gelling agent to contact a particulate solid starting material in a low-shear granulator, wherein the 0.^₁₂ average droplet diameter

(Sauter Mean Diameter) of the liquid binder is not greater than 10 times, preferably not greater than 5 times, more preferably not greater than 2 times and most preferably not greater than the

average particle diameter of that fraction of the total solid starting material which has a d-₃,₂ particle diameter of from 20 μm to 200 μm. If more than 90% by weight of the solid starting material has a d₃₍₂ average particle diameter less than 20 μm then the U^₁₂ average particle diameter of the total solid starting material is taken to be 20 μm and if more than 90% by weight of the solid starting material has a d₃,₂ average particle diameter greater than 200 μm then the d₃,₂ average particle diameter of the total solid starting material is taken to be 200 μm.

Since most of the processes described above are used to produce granular detergents or detergent components it may well be convenient to produce the detergent component of the present invention in the form of granules. However, if a fine powder is desired process conditions can readily be adjusted to achieve this.

The aqueous solution, dispersion or emulsion of detergent ingredient

The process of the present invention can be applied to any- detergent ingredient which is available in liquid form. For example it can be applied to any surfactant available associated with water as a solvent. It is especially applicable to surfactants which are difficult or impossible to obtain in a solid form suitable for further powder processing. However, it is envisaged that it could be applied to any suitable surfactant to improve its powder handling characteristics. It is likely to find most application in the treatment of anionic and non-ionic surfactants, which comprise the bulk of the surfactant component of most detergent powder compositions.

Anionic surfactants are well-known to those skilled in the art. Examples include alkylbenzene sulphonates, particularly linear alkylbenzene sulphonates having an alkyl chain length of Cs-Cis; primary and secondary alkylsulphates, particularly C₈-C₂₀ primary alkyl sulphates; alkyl ether sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates. Sodium salts are generally preferred. - S -

Nonionic surfactants that may be used include the primary and secondary alcohol ethoxylates, especially the C₈-C₂₀ aliphatic alcohols ethoxylated with an average of from 1 to 20 moles of ethylene oxide per mole of alcohol, and more especially the C₁₀-C₁₅ primary and secondary aliphatic alcohols ethoxylated with an average of from 1 to 10 moles of ethylene oxide per mole of alcohol. Non-ethoxylated nonionic surfactants include alkylpolyglycosides, glycerol monoethers, and polyhydroxyamides (glucamide) .

Water-soluble cationic surfactants include quaternary ammonium salts of the general formula R₁R₂R₃R₄N X wherein

Ri is a relatively long (Cg-Cis) hydrocarbon chain, typically an alkyl, hydroxyalkyl or ethoxylated alkyl group, optionally interrupted with a heteroatom or an ester or amide group; each of R₂, R₃ and R₄ (which may be the same or different) is a short-chain (C₁-C₃) alkyl or substituted alkyl group; and X is a solubilising anion, for example a chloride, bromide or methosulphate ion. Other classes of cationic surfactant include cationic esters (for example, choline esters) .

Zwitterionic surfactants include betaines. An especially preferred material is cocoamidopropyl betaine (CAPB) , in which RQ is C₁₂-C₁₄ alkyl and m is 3.

Preferred amphoteric surfactants include alkyl amine oxides of the general formula R₇R₈R₉N-K) wherein R₇ is typically a Cs-Ci_S alkyl group, for example, C₁₂-C₁₄ alkyl, and Rs and

Rg, which may be the same or different, are C₁-C₃ alkyl or hydroxyalkyl groups, for example, methyl groups. The most preferred amine oxide is coco dimethylamine oxide, in which R₇ is C₁₂-C₁₄ alkyl and Rs and Rg are methyl groups.

These lists of surfactants are not intended to be exhaustive and the use of any surfactant suitable for incorporation in particulate laundry detergent compositions and capable of forming an aqueous solution falls within the scope of the present invention.

Other detergent ingredients which are available in liquid form include polymers, antifoams and sequestrants .

Organic Ge11ant Materials

The organic gelling agent may comprise any composition capable of forming a gel and drying to a friable solid. Suitable materials include gelatines, the alginates and alganic acids, pectins and starches. One factor in the choice of gelling agent will be its behaviour at the pH of the aqueous surfactant. A particularly favoured gelling agent is gelatine.

Detergent Compositions

Granular detergent products typically consist of one or more types of granular component, often admixed with one or more post dosed powdered ingredients. Optionally, one or more of - li ¬

the granular components may be sprayed with one or more liquid materials after they have been formed.

Detergent compositions of the invention comprise surfactant and organic gelling agent, along with any residual water and/or usual impurities, and may also contain other detergent-active compounds and detergency builders, and may optionally contain bleaching components and other active ingredients, as outlined below, to enhance performance and properties. Any one or more of such other materials may alternatively be incorporated wholly or partly in the granular component of the present invention, with the remaining components supplied in any convenient form. This may comprise one or more other granular components, each containing a single ingredient and/or a mixture of ingredients. Alternatively, one or more of the other ingredients may be post dosed in powder or liquid form. A combination of the two methods may be used.

For some markets a single granular component according to any aspect of the present invention may be sold as a finished product. Alternatively, it may be used in conjunction with other components to produce the finished detergent product. Where a detergent composition according to the invention contains more than one granular component at least one of the granular components must be in accordance with the present invention. Any or all of the other granular components may also be in accordance with the present invention. Detergent-active compounds (surfactants) may be chosen from soap and non-soap anionic, cationic, nonionic, amphoteric and zwitterionic detergent-active compounds, and mixtures thereof. Many suitable detergent-active compounds are available and are fully described in the literature, for example, in "Surface-Active Agents and Detergents", Volumes I and II, by Schwartz, Perry and Berch. The preferred detergent-active compounds that are used are soaps and synthetic non-soap anionic and nonionic compounds. The total amount of surfactant present is suitably within the range of from 5 to 40 wt%.

Cationic, amphoteric and zwitterionic surfactants may also form part of the surfactant system. They will generally be present in combination with anionic surfactants, the weight ratio of anionic surfactant to cationic, amphoteric or zwitterionic surfactant being at least 1:1.

The detergent compositions of the invention also contain one or more detergency builders. The total amount of detergency builder in the compositions will suitably range from 5 to 80 wt%, preferably from 10 to 60 wt%. As disclosed above, in a preferred aspect of the invention detergency builder is combined with surfactant solution and organic gelling agent. In this case all or part of the detergency builder may be added at this stage, any shortfall being added in a post dosing stage.

Preferred builders are alkali metal aluminosilicates, more especially crystalline alkali metal aluminosilicates zeolites) , preferably in sodium salt form. The compositions of the invention may also contain phosphate builders, for example, sodium tripolyphosphate, either alone or in combination with aluminosilicates .

The aluminosilicate used in most commercial particulate detergent compositions is zeolite A. Advantageously, however, maximum aluminium zeolite P (zeolite MAP) described and claimed in EP-A-384 070 may be used. Zeolite MAP is an alkali metal aluminosilicate of the P type having a silicon to aluminium ratio not exceeding 1.33, preferably not exceeding 1.15, and more preferably not exceeding 1.07.

Zeolite or phosphate builders may suitably be present in a total amount of from 5 to 60 wt%, preferably from 10 to 50 wt%. The zeolites may be supplemented by other inorganic builders, for example, amorphous aluminosilicates, or layered silicates such as SKS- 6 ex Clariant.

The zeolites may be supplemented by organic builders, for example, polycarboxylate polymers such as polyacrylates and acrylic/maleic copolymers; monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono-, di- and trisuccinates, carboxymethyloxysuccinates, carboxymethyloxymalonates, dipicolinates, hydroxyethyliminodiacetates, alkyl- and alkenylmalonates and succinates; and sulphonated fatty acid salts.

Especially preferred organic builders are citrates, suitably used in amounts of from 1 to 30 wt%, preferably from 2 to 15 wt%; and acrylic polymers, more especially acrylic/maleic copolymers, suitably used in amounts of from 0.5 to 15 wt%, preferably from 1 to 10 wt%. Builders, both inorganic and organic, are preferably present in alkali metal salt, especially sodium salt, form.

These lists of builders are not intended to be exhaustive.

Detergent compositions according to the invention may also suitably contain a bleach system. Preferably this will include a peroxy bleach compound, for example, an inorganic persalt or an organic peroxyacid, capable of yielding hydrogen peroxide in aqueous solution.

Preferred inorganic persalts are sodium perborate monohydrate and tetrahydrate, and sodium percarbonate, the latter being especially preferred. The sodium percarbonate may have a protective coating against destabilisation by moisture. The peroxy bleach compound is suitably present in an amount of from 5 to 35 wt%, preferably from 10 to 25 wt% .

The peroxy bleach compound may be used in conjunction with a bleach activator (bleach precursor) to improve bleaching action at low wash temperatures. The bleach precursor is suitably present in an amount of from 1 to 8 wt%, preferably from 2 to 5 wt% . Preferred bleach precursors are peroxycarboxylic acid precursors, more especially peracetic acid precursors and peroxybenzoic acid precursors; and peroxycarbonic acid precursors. An especially preferred bleach precursor suitable for use in the present invention is N, N, N¹ ,N¹ -tetracetyl ethylenediamine (TAED). A bleach stabiliser (heavy metal sequestrant) may also be present. Suitable bleach stabilisers include ethylenediamine tetraacetate (EDTA) , diethylenetriamine pentaacetate (DTPA) , ethylenediamine disuccinate (EDDS) , and the polyphosphonates such as the Dequests (Trade Mark) , ethylenediamine tetramethylene phosphonate (EDTMP) and diethylenetriamine pentamethylene phosphate (DETPMP) .

The compositions of the invention may contain alkali metal, preferably sodium, carbonate, in order to increase detergency and ease processing. Sodium carbonate may suitably be present in amounts ranging from 1 to 60 wt%, preferably from 2 to 40 wt%.

Sodium silicate may also be present, suitably in an amount of from 0.1 to 5 wt%.

Powder flow may be improved by the incorporation of a small amount of a powder structurant. Examples of powder structurants, some of which may play also other roles in the formulation, include, for example, fatty acids (or fatty acid soaps) , sugars, acrylate or acrylate/maleate polymers, sodium silicate, and dicarboxylic acids (for example, Sokalan (Trade Mark) DCS ex BASF) . One preferred powder structurant is fatty acid soap, suitably present in an amount of from 1 to 5 wt%.

Other materials that may be present in detergent compositions of the invention include antiredeposition agents such as cellulosic polymers; soil release agents; anti-dye-transfer agents; fluorescers; inorganic salts such as sodium sulphate; enzymes (proteases, lipases, amylases, cellulases) ; dyes; coloured speckles; perfumes; and fabric conditioning compounds. This list is not intended to be exhaustive.

The detergent compositions of the invention are in particulate form. Particulate detergent compositions comprise powders, and tablets of compacted powder.

An important property of detergent powder compositions is bulk density. The organic gellant/surfactant component may be added to compositions comprising any suitable bulk density. Powders of low to moderate bulk density are commonly prepared by spray-drying a slurry, and optionally postdosing further ingredients by dry-mixing. If such a process is used the organic gellant/surfactant component of the present invention is preferably added at the postdosing dry mixing stage .

As outlined above, the bulk density of the organic gellant and surfactant component in combination with produced by non spray drying routes may be lower that that of powders commonly produced by such routes . The processes and components of the present invention are, therefore, particularly advantageous when used to produce low bulk density detergent compositions by the non spray drying route .

"Concentrated" or "compact" powders may be prepared by mixing and granulating processes, for example, using a highspeed mixer/granulator, or other non-tower processes. Such processes may also be adapted to produce low bulk density powders. For all such processes, the organic gellant/surfactant component may be added at a post dosing dry mixing stage, or may be formed in-situ during a suitable processing stage where organic gellant and surfactant are combined in the presence of other components of the detergent composition.

EXAMPLES

Example 1

Dissolve 5% of gelatine in a heated (60⁰C) DBIlOA emulsion ex dow corning (10% active) .

Make a thin film out of this using a film coater.

Allow this to dry at low humidity conditions for 3 days

Flake the resulting sheet into small particles. The resulting particles are hard and solid.

Example 2

Dissolve 5% of gelatine in a heated (60⁰C) Praepagen HY (40.6% active) . Make a thin film out of this using a film coater. Allow this to dry at low humidity conditions for 3 days. Flake the resulting sheet into small particles. The resulting particles are hard and solid.

Claims

1. A process for the preparation of a particulate detergent component comprising an organic gelling agent, which process comprises absorbing a liquid detergent ingredient, which is an aqueous solution, dispersion or emulsion of detergent ingredient, into the gelling agent and removing water by an evaporative process .

2. A process as claimed in claim 1, wherein the component comprises from 20 to 80 wt%, preferably from 30 to 70 wt% of detergent ingredient.

3. A process as claimed in claim 1, wherein the detergent ingredient comprises an anionic surfactant .

4. A process as claimed in claim 1 or claim 2, wherein the detergent ingredient comprises a nonionic surfactant.

5. A process as claimed in any preceding claim, wherein the detergent ingredient comprises a cationic surfactant .

6. A process as claimed in any preceding claim, wherein the organic gelling agent is selected from the group consisting of gelatines, the alginates and alganic acids, pectins, starches and mixtures thereof, preferably gelatine.

7. A process as claimed in any preceding claim, wherein the aqueous solution, dispersion or emulsion of detergent ingredient, the organic gelling agent and the other components of a laundry detergent composition are mixed in a high shear mixer.

8. A process as claimed in any preceding claim, wherein the aqueous solution, dispersion or emulsion of detergent ingredient, the organic gelling agent and the other components of a laundry detergent composition are mixed in a low shear mixer.

9. A process according to claim 8, wherein the low shear mixer comprises a gas fluidisation granulator.

10. A process as claimed in any preceding claim, wherein the maximum temperature of the detergent component during the process is 80⁰C.

11. A process as claimed in any preceding claim, wherein the detergent component is produced in granular form.

12. A detergent component comprising an organic gelling agent, preferably gelatine.

13. A detergent component according to claim 13 further comprising other components of a laundry detergent composition.

14. A detergent composition as claimed in claim 12 or claim 13 which comprises an insoluble particulate carrier material .

15. A particulate laundry detergent composition comprising in total from 5 to 60 wt% of one or more organic detergent surfactants, from 10 to 80 wt% of one or more detergency builders and optionally other detergent ingredients, which composition includes a detergent component as defined in claims 12 to 14.