EP0828817A1

EP0828817A1 - Detergent composition and process for its production

Info

Publication number: EP0828817A1
Application number: EP96916117A
Authority: EP
Inventors: Huig Euser; Johan Cristiaan Klein-Velderman
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 1995-05-26
Filing date: 1996-05-14
Publication date: 1998-03-18
Anticipated expiration: 2016-05-14
Also published as: DE69620600T2; GB9510695D0; ZA963785B; ES2174071T3; DE69620600D1; EP0828817B1; AU5898996A; WO1996037599A1; AU717098B2; BR9609076A

Abstract

A granular detergent composition having a bulk density of at least 650 g/l, containing a granular base powder obtainable by a process involving a mechanical mixing step which contains an organic surfactant system, detergent builder and a soap, and further containing, as a post dosed material, less than 30 % of an inorganic sulphate salt having average particle size of at least 250 microns wherein no more than 25 % of the salt has a particle size less than 180 microns, or, not more than 20 wt.% of an inorganic sulphate salt having an average particle size of less than 350 microns wherein no more than 40 % of the said salt has a particle size less than 180 microns; provided that the inorganic sulphate salt is not agglomerated with fabric softening clay.

Description

DETERGENT COMPOSITION AND PROCESS FOR ITS PRODUCTION

The present invention relates to a particulate detergent composition and a process for producing it. In particular, the invention relates to a detergent composition of high bulk density comprising a base powder and a post dosed salt having specified characteristics. The invention further relates to a process for producing such a composition without the use of a spray drying tower.

It is known to produce particulate granular detergent compositions by means of a spray drying process. In such a process an aqueous slurry of the spray dryable detergent components is fed to a spray drying tower and contacted with hot air whereby particles of the detergent composition are produced. This process produces particles which have a high porosity and a bulk density generally not in excess of about 650g/l.

In recent years, there has been a trend in the detergents market towards powders of high bulk density which may be prepared by processes which included densification of spray dried powders or even mixing and a glomeration of the starting material without the use of a spray drying step. Such powders typically have a bulk density significantly in excess of 650g/l and often in excess of 750g/l. Such powders generally have a low porosity which may adversely effect the delivery of such powders.

Historically, phosphates have been employed in detergent compositions to provide a building function. However, due primarily to environmental concerns, phosphate builders have in many countries been replaced by alternative builders such as zeolites. The move towards higher bulk densities and the use of zeolite builder systems has led to certain powder performance difficulties, for example in the delivery of the active ingredients of the powder to the wash liquor in an automatic washing machine. Such difficulties are observed especially at ambient water temperature and low water pressure. Delivery of the powder involves, firstly, dispensing it into the wash liquor and, secondly, dissolution of the powder in the wash. The powder is typically dispensed by means of the dispenser drawer of the washing machine or from a dispensing device, for example a wash ball which is placed in the drum of the washing machine with the fabrics which are to be washed.

An aim of the present invention is to provide a detergent composition of high bulk density, preferably a zeolite built composition, which provides acceptable dispensing characteristics of the detergent composition in wash water.

GB-A-2172311 discloses the use of a fabric softening agglomerate of fabric softening clay and water soluble ionisable salt (for example sodium sulphate) in the manufacture of a fabric softening particulate detergent composition. The agglomerate is of particle size in the range of nos 10 to 140 US sieves, preferably nos 40 to 100 US sieves, to give good pouring properties, low dust, rapid disintegration of agglomerate in water and resistance to size reduction in storage.

The problem of providing a detergent composition of high bulk density having good dispensing characteristics has been addressed in GB-A-2283756 in which detergent compositions having a base powder with a low level of fine particles are disclosed as providing a suitable solution to this problem. However removal of fine material to a low level generally requires strict control of the production process and, hence may introduce complications into the process control system.

It has been surprisingly found that detergent compositions of high bulk density having good dispensing characteristics in wash water may be obtained by providing a detergent composition comprising a base powder which contains soap and a post dosed sulphate having specified characteristics as regards its specification and level in the composition. Furthermore such compositions may allow a less strict specification of fines in the base powder while retaining good dispensing properties.

Accordingly the present invention provides a granular detergent composition having a bulk density of at least 650g/l, the composition comprising a granular base powder obtainable by a process involving a mechanical mixing step and which contains from 15 to 50wt% on the base powder of an organic surfactant system, from 20 to 70wt% on the base powder (anhydrous basis) of a detergent builder and from 0.1 to 10wt% on the base powder of a soap, the composition further comprising as a post dosed material; a) less than 30wt% on the composition of an inorganic sulphate salt having average particle size of at least

250 microns wherein no more than 25% by weight of the sulphate salt has a particle size less than 180 microns; or b) not more than 20wt% on the composition of an inorganic sulphate salt, having an average particle size of less than 350 microns wherein no more than 40% of the said salt has a particle size less than 180 microns; provided that the inorganic sulphate salt is not agglomerated with fabric softening clay. All the percent figures are by weight based on the detergent composition unless otherwise stated. The term "fines" as employed herein denotes material having a particle size of 180 microns or less.

Advantageously, improved dispensing may be secured by reducing the level of fine material in the post dosed inorganic sulphate or by reducing the level of post dosed sulphate and incorporating an inorganic sulphate into the base powder and/or providing an additional post dosed salt, for example carbonate and bicarbonate.

The invention further provides a process for the production of a particulate detergent composition having a bulk density of at least 650g/l which comprises mixing a particulate starting material to form a granular base powder comprising 15-50wt% on base powder of a surfactant, 20-70wt% on base powder of the builder and 0.1-10wt% on base powder of the soap and post dosing to the said base powder; a) less than 30wt% on the composition of an inorganic sulphate salt having an average particle size of at least 250 microns wherein no more than 25% by weight of the sulphate salt has a particle size less than 180 microns; or b) less than 20wt% on the composition of an inorganic sulphate salt having an average particle size of less than 350 microns wherein no more than 40% of the said salt has a particle size less than 180 microns; provided that the inorganic sulphate salt is not agglomerated with fabric softening clay

The particulate starting materials may comprise a spray- dried powder optionally with other ingredients, individual components of the base powder such as a surfactant, a detergent builder and a soap, adjuncts comprising 2 or more components or mixtures thereof.

The invention further provides the use of a particulate inorganic sulphate salt having an average particle size of at least 250 microns wherein no more than 25% by weight of the sulphate has a particle size less than 180 microns to improve the dispensing properties of a particular detergent composition having a bulk density of at least 650g/l comprising a base powder obtainable by a process involving a mixing step and which powder comprises 15-50wt% on base powder of surfactant, 20-70wt% on base powder of a detergent builder and 0.1-10wt% on base powder of a soap, wherein the said particulate sulphate salt is present in an amount of less than 30wt% based on the detergent composition; provided that the inorganic sulphate salt is not agglomerated with fabric softening clay.

The invention also provides the use of a particulate inorganic sulphate salt having an average particle size of less than 350 microns wherein no more than 40% by weight of the sulphate has a particle size less than 180 microns to improve dispensing properties of a particulate detergent composition having a bulk density of at least 650g/l comprising a base powder obtainable by a process involving a mixing step, the said powder comprising 15-50wt% on base powder of a surfactant, 20-70wt% on base powder of a detergent builder and 0.1-10wt% on base powder of a soap wherein the said particulate sulphate is present in an amount of not more than 20wt% on the composition and, optionally, wherein the detergent composition further comprises; a) as a post-dosed material, less than 20wt% on the composition of an additional inorganic salt, preferably a carbonate and/or bicarbonate salt; and/or b) as a component of the base powder, at least 5wt% on the composition of an inorganic sulphate salt; provided that the inorganic sulphate salt is not agglomerated with fabric softening clay.

Suitably, the sulphate salt comprises an alkaline metal sulphate and preferably sodium sulphate. The sulphate salt suitably has a bulk density of at least lOOOg/1 and desirably at least 1200g/l. The high bulk density of the post dosed sulphate provides flexibility by allowing other post dosed ingredients having a lower bulk density to be employed while the bulk density of the overall composition may be maintained at a high level .

Where the post dosed sulphate is present at a level of less than 30% and contains less than 25% by weight of particles having a particle size less than 180 microns, it is preferred that the average particle size of the sulphate be at least 275 microns, especially at least 300 microns. Suitably, the average particle size of the sulphate in this case does not exceed 800 microns, and preferably is not in excess of 700 microns in order to provide a suitable granulometry.

In the case where the post dosed sulphate has a fines level of no more than 40%, and is present at a level of not more than 20%, the average particle size of the post dosed sulphate is desirably not in excess of 325 microns. It is further preferred in this case, that the average particle size of the sulphate is at least 225 microns. In this case the composition preferably contains sulphate in the base and/or an additional post-dosed salt.

Where the base powder contains an inorganic sulphate salt, it may be present at a level of at least 10% and more preferably at least 15wt% on the composition of inorganic sulphate salt. Preferably, the level of sulphate salt in the base powder is no more than 25wt% based on the detergent composition. Desirably the total sulphate salt content of the composition, that is base powder and post-dosed content combined, is 15 to 30%, preferably 20 to 30%, for example 25% based on the composition.

Preferably, the inorganic sulphate salt is added in substantially pure form, for example as a powder. Other adjuncts may be dry mixed with such a powder, or with the base powder. Alternatively, the inorganic sulphate salt may be added in a form in which it is combined with a carbonate or bicarbonate. Such a combination may be obtained for example as a double salt, by spray drying a mixture of the salts, or by drying a paste of the mixed salts. In a preferred embodiment, the sulphate is added in the form of burkeite. Other adjuncts may be dry mixed with such a combination.

The additional salt, if present, suitably comprises an alkaline metal carbonate and/or bicarbonate. Preferably sodium salts are employed. If present, the additional post dosed salt is suitably present in an amount of less than 15% and preferably no more than 12%, for example 10% by weight of the detergent composition. The additional post dosed salt suitably has an average particle size of 250 to 800 and preferably 300 to 750 microns. Preferably, no more than 40% by weight of an additional salt has a particle size less than 180 microns. Suitably the additional salt has a bulk density of at least lOOOg/l and preferably no more than 1600g/l.

If desired, the detergent composition may contain an inorganic sulphate in the base powder together with an additional post dosed inorganic salt but in such a case it is highly preferred that the sum of both of these salts does not exceed 50% by weight, preferably 45% by weight based on the composition.

The base powder preferably has a bulk density of at least 750g/l, desirably at least 850g/l, for example about lOOOg/l. The components employed and the production process will determine the maximum bulk density which may be obtained. Preferably the base powder has an average particle size of 350-900 microns, desirably 400-750 microns and optimally 500-750 microns.

It is preferred that the base powder has a low level of fine material in order to improve further the dispensing characteristics of the detergent composition and so preferably contains less than 20%, more preferably less than 10% and especially less than 5% fines from the point of view of improving dispensing characteristics.

As noted above however, a strict specification as regards the level of fine material in the base powder requires closer process control and therefore toleration of a higher level of fine material in the detergent composition is desirable from the process perspective.

The combination of soap in the base powder and post dosed sulphate in the present invention provides improved dispensing and hence the significant advantage of allowing greater flexibility as regards the specification of the level of fines in the base powder. Having regard to both dispensing behaviour and ease of processing, the base powder optimally has a fines content of 5 to 30%, and preferably 10 to 25% and especially 15 to 25%. We have further determined that good dispensing characteristics may be secured where the base powder contains up to 30% fine material especially if the post dosed sulphate contains less than 30%, and preferably no more than 25% of fine material.

Suitably the base powder constitutes 40-90%, 45-75% and especially 48-70% by weight of the detergent composition. In addition to the base powder and the post dosed sulphate and optionally other salts, the detergent composition may comprise other conventional post dosed ingredients including bleaches, enzymes and the like.

Suitably a detergent composition according to the invention provides a powder residue, expressed as a dry weight of less than 8% and preferably less than 5% of the powder dosed into a PHILIPS AWB/127 dispenser at a water temperature of 20^*'C, preferably 10°C and a flow rate of 5 litres per minute for 1 minute.

The excellent dispensing characteristics of powders according to the present invention provides the consumer benefits of ensuring that the appropriate dosage of powder reaches the wash liquor, avoiding significant waste and reducing the need to clean the dispensing device, whether it be a dispensing drawer or a dosing device placed into the washing drum.

The surfactant system may comprise soap and non-soap anionic, cationic, 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.

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 C_ε-C_ι;; primary and secondary alkyl sulphates, particularly C_i:-C₁₅ primary alkyl sulphates; alkyl ether sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates. Sodium salts are generally preferred.

Nonionic surfactants that may be employed in the composition include the primary and secondary alcohol ethoxylates, especially the C₆-C₁₀ 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 also glycerol monoethers, and polyhydroxyamides (glucamide) .

The choice of detergent-active compound (surfactant), and the amount present, will depend on the intended use of the detergent composition. For example, for machine dishwashing a relatively low level of a low-foaming nonionic surfactant is generally preferred. In fabric washing compositions, different surfactant systems may be chosen, as is well known to the skilled formulator, for handwashing products and for products intended for use in different types of washing machine.

The total amount of surfactant present will also depend on the intended end use. In compositions for machine washing of fabrics, an amount of from 5 to 40 wt% is generally appropriate.

Inorganic builders that may be present include sodium carbonate, if desired in combination with a crystallisation seed for calcium carbonate, as disclosed in GB 1 437 950 (Unilever); crystalline and amorphous aluminosilicates, for example, zeolites as disclosed in GB 1 473 201 (Henkel) , amorphous aluminosilicates as disclosed in GB 1 473 202 (Henkel) and mixed crystalline/amorphous aluminosilicates as disclosed in GB 1 470 250 (Procter & Gamble); and layered silicates as disclosed in EP 164 514B (Hoechst) . Inorganic phosphate builders, for example, sodium orthophosphate, pyrophosphate and tripolyphosphate, may also be present, but on environmental grounds those are no longer preferred.

Preferably the detergent composition is substantially free of phosphate.

Zeolite builders may suitably be present in amounts of from 10 to 50 wt%. The zeolite used in most commercial particulate detergent compositions is zeolite A. Advantageously, however, maximum aluminium zeolite P (zeolite MAP) described and claimed in EP 384 070A (Unilever) 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.

Organic builders that may be present include polycarboxylate polymers such as polyacrylates, acrylic/maleic copolymers, and acrylic phosphinates; 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. This list is not intended to be exhaustive.

Especially preferred organic builders are citrates, nitrolotriacetic acid and oxydisuccinate and are suitably used in amounts of from 5 to 30 wt%, preferably from 10 to 25 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.

The base powder is produced at least in part by a process involving a mechanical mixing step. The process may comprise a spray-drying step followed by a mixing step if desired, but the base powder is desirably produced by a process in which a spray drying step is not present. Preferably the base powder is produced by a granulation process comprising a mixing step and preferably a densification step. The process may be continuous or a batch process as desired. Where a continuous granulation process is employed to produce the base powder, mixing is suitably carried out using a high speed mixer, suitable examples include a Shugi (trademark) Granulator, a Drais (trade mark) K-TTP 80 Granulator and the Lodige (trade mark) CB30 recycler. The residence time in the mixing step is suitably about 2 to 30 seconds and the rate of mixing in the apparatus is suitably in the range 100 to 2500rpm depending upon the degree of densification and the particle size required. A granulation step may be employed if desired and may be carried out using a lower speed mixer for example, the Drais (trade mark) K-T 160 and the Lodige (trade mark) KM300 mixer. The residence time in the granulation step is suitably about 1 to 10 minutes and the rate of mixing in the apparatus is about 40 to 160 rpm. A drying and/or cooling step may be employed in the continuous process, using, for example a fluid bed dryer. An especially preferred production process is described in EP367339. If desired, batch processing may be employed and suitable mixers include the FUKAE range of mixers.

Detergent compositions produced by the process of the invention are preferably admixed with a bleach system. Machine dishwashing compositions may suitably contain a chlorine bleach system, while fabric washing compositions may more desirably contain peroxy bleach compounds, for example, inorganic persalts or organic peroxyacids, capable of yielding hydrogen peroxide in aqueous solution.

Suitable peroxy bleach compounds include organic peroxides such as urea peroxide, and inorganic persalts such as the alkali metal perborates, percarbonates, perphosphates, persilicates and persulphates . Preferred inorganic persalts are sodium perborate monohydrate and tetrahydrate, and sodium percarbonate.

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,N' ,N' -tetracetyl ethylenediamine (TAED) . Other materials that may be present include sodium silicate and sodium metasilicate; antiredeposition agents such as cellulosic polymers; fluorescers; lather control agents or lather boosters as appropriate; enzymes, for example proteolytic and lipolytic enzymes; dyes; coloured speckles; perfumes; foam controllers; and fabric softening compounds. This list is not intended to be exhaustive.

The invention will now be illustrated by way of non limiting Examples.

Example 1 and A

Detergent compositions according to the present invention and comparative compositions were prepared by producing a base powder and admixing various components to the powder. Two base powders were produced, one containing a soap and one without a soap for comparative purposes. The components of the base powders are listed below.

Example 1 Comparative A

Na LAS ^** 6.2 6.8

Nonionic 7 EO ^: 3.3 3.6

Nonionic 3 EO ^* 1.7 1.9

Na-soap (C16/18) 0.8 0.0

Zeolite 4A 23.0 25.8

Polymer ^*■ 0.7 0.7

SCMC 0.4 0.4

Sodium carbonate 6.0 6.7

Water minors 8.0 9.0

^a Linear alkylbenzensulphonate, sodium salt ^b SYNPERONIC A7 and A3 (ex ICI) ^c Acrylic acid/maleic acid copolymer SCMC - sodium carboxy methal cellulose

The figures represent parts by weight of each component

The components were fed to a LODIGE CB 30 Recycler mixer which was operated at a tip speed of 23ms^"1 and the residence time was 3 seconds. The mixture was then fed to a LODIGE Ploughshare mixer and densified at a temperature of about 60°C, a rotational speed of 120rpm and a residence time of 3 minutes. The resulting granules were then cooled/dried in fluid bed in which fine material (less than 180 microns) was elutriated whereby a base powder having a fines content of 5 to 30% was obtained.

The base powders were then mixed with the post dosed ingredients listed below; a variety of grades of sodium sulphate were employed.

Example 1 Comparative A

Perborate Tetrahydrate 10.0 10.0

TAED 2.3 2.3

DEQUEST 2047 ^'* 0.4 0.4

Sodium sulphate 25.0 24.3

Sodium carbonate 10.3 4.5

Sodium silicate 0.0 1.5

Antifoam/fluorescer 1.7 1.8

Enzyme 0.3 0.3

Perfume 0.2 0.2

ex Monsanto

The dispensing characteristics of the series of powders produced were determined by the following procedure. A lOOg dose of the powder was placed in a heap at the front end of the main compartment of the dispenser drawer of a PHILIPS AWB/127 washing machine and subjected to a water fill of 5 litres at 20°C and an inlet pressure of 50kPa flowing in over a period of one minute. After one minute the flow of water was ceased and the powder remaining was collected and dried to constant weight. The dry weight of powder recovered from the dispenser drawer represents the weight percentage of powder not dispensed to the machine (the residue) . Every result is the average of two duplicate measurements. The results are shown in the following tables:

Example 1 base powder

Base powder fines

Dispenser Residue (%)

Sulphate fines 15 20 25 30 (%)

10 5 4 3 4

20 4 5 4 4

30 10 10 (comparative)

40 17 10 (comparative)

Comparative A base powder

Base powder fines

Dispenser Residue (%)

Sulphate fines 5 10 15 25 (%)

20 10 13 12 29 It is noted that, at a sulphates fines level of 20% Comparative A shows poor dispensing properties as compared to compositions of the invention demonstrating that higher levels of fine material may be tolerate where the base powder contains soap.

Example 2

A series of base powders were produced according to the method and composition described in Example 1 and similar base powders containing the same components but with between 10 and 25 parts by weight of sodium sulphate were also produced according to the same method as described in Example 1. Sodium sulphate of various specifications (5% fine, and 35% fine were post dosed to these base powders in various quantities (10 to 25 parts by weight) together with the other post dosed components listed in example 1.

The dispenser residues of these powders were then determined. The results are shown below.

Sulphate (base) - 15 - 10 -

Sulphate (post dose) 25 10 15 15 20

Carbonate (post dose) - - 10 - 5

Dispenser residues

Sulphate 5% fines 1 1 - - -

Sulphate 35% fines 23* 4 2 8 8

* comparative

The results demonstrate that good dispensing may be secured at a high dosage of sulphate with a low fines content and for lower doses of sulphate (up to 20%) with a higher level of fines. It is also observed that replacing some of the post- dosed sulphate with post-dosed carbonate or incorporating some of the sulphate into the base powder provided an improvement in dispensing properties.

Claims

1 A granular detergent composition having a bulk density of at least 650g/l, the composition comprising a granular base powder obtainable by a process involving a mechanical mixing step and which contains from 15 to 50wt% on the base powder of an organic surfactant system, from 20 to 70wt% on the base powder (anhydrous basis) of a detergent builder and from 0.1 to 10wt% on the base powder of a soap, the composition further comprising as a post dosed material; a) less than 30wt% on the composition of an inorganic sulphate salt having average particle size of at least 250 microns wherein no more than 25% by weight of the sulphate salt has a particle size less than 180 microns; or b) not more than 20wt% on the composition of an inorganic sulphate salt having an average particle size of less than 350 microns wherein no more than 40% of the said salt has a particle size less than 180 microns; provided that the inorganic sulphate salt is not agglomerated with fabric softening clay.

2 A process for the production of a particulate detergent composition having a bulk density of at least 650g/l which comprises mixing a particulate starting material to form a granular base powder comprising 15-50wt% on base powder of a surfactant, 20-70wt% on base powder of the builder and 0.1-10wt% on base powder of the soap and post dosing to the said base powder; a) less than 30wt% on the composition of an inorganic sulphate salt having an average particle size of at least 250 microns wherein no more than 25% by weight of the sulphate salt has a particle size less than 180 microns; or b) less than 20wt% on the composition of an inorganic sulphate salt having an average particle size of less than 350 microns wherein no more than 40% of the said salt has a particle size less than 180 microns; provided that the inorganic sulphate salt is not agglomerated with fabric softening clay

3 Use of a particulate inorganic sulphate salt having an average particle size of at least 250 microns wherein no more than 25% by weight of the sulphate has a particle size less than 180 microns to improve the dispensing properties of a particular detergent composition having a bulk density of at least 650g/l comprising a base powder obtainable by a process involving a mixing step and which powder comprises 15-50wt% on base powder of surfactant,

20-70wt% on base powder of a detergent builder and 0.1- 10wt% on base powder of a soap, wherein the said particulate sulphate salt is present in an amount of less than 30wt% based on the detergent composition; provided that the inorganic sulphate salt is not agglomerated with fabric softening clay.

4 Use of a particulate inorganic sulphate salt having an average particle size of less than 350 microns wherein no more than 40% by weight of the sulphate has a particle size less than 180 microns to improve dispensing properties of a particulate detergent composition having a bulk density of at least 650g/l comprising a base powder obtainable by a process involving a mixing step, the said powder comprising 15-50wt% on base powder of a surfactant, 20-70wt% on base powder of a detergent builder and 0.1-10wt% on base powder of a soap wherein the said particulate sulphate is present in an amount of not more than 20wt% on the composition; provided that the inorganic sulphate salt is not agglomerated with fabric softening clay.

5 Use of a particulate inorganic sulphate salt according to claim 4 wherein the detergent composition further comprises; a) as a post-dosed material, less than 20wt% on the composition of an additional inorganic salt, preferably a carbonate and/or bicarbonate salt; and/or b) as a component of the base powder, at least 5wt% on the composition of an inorganic sulphate salt.