GB2221695A - Granular detergents - Google Patents

Abstract

A process for the preparation of detergent powder of high bulk density comprises neutralising a detergent acid (anionic surfactant precursor), eg linear alkylbenzene sulphonic acid, by gradually adding it to a particulate solid water-soluble alkaline inorganic material, for example, sodium carbonate (optionally plus other alkaline materials, detergency builders etc), in a high-speed mixer/granulator, eg Fukae mixer, and granulating the product in the mixer in the presence of a liquid binder. The liquid to solid ratio is kept low throughout the neutralisation step, so that the reaction mixture remains in particular form throughout the process.

Description

DETERGENT COMPOSITIONS AND PROCESS FOR PREPARING THEM TECHNICAL FIELD The present invention relates to granular detergent compositions and components of high bulk density, and their preparation by a dry neutralisation process.

BACKGROUND AND PRIOR ART Recently there has been considerable interest within the detergents industry in the production of detergent powders having relatively high bulk density, for example, 650 g/litre and above. It has been suggested that such powders containing anionic surfactants, for example alkyl benzene sulphonate, may be prepared by methods involving in-situ neutralisation of an acid precursor of the anionic surfactant with an alkali such as sodium hydroxide or sodium carbonate.

For example, JP 60 072 999A (Kao) and GB 2 166 452B (Kao) disclose a process in which detergent sulphonic acid, sodium carbonate and water are mixed in a strongly shearing apparatus; the solid mass obtained is cooled to 40 C or below and pulverised; and the fine powder thus obtained is granulated. This process is typical of those disclosed in the art in that the product of the neutralisation reaction is a doughy mass, and the reaction requires apparatus such as a kneader with a very high energy reguirement; and separate pulverisation and granulation steps in different apparatus are required in order to obtain an acceptable granular detergent product.

There has also been considerable recent interest in the use of high-speed mixer/granulators in the preparatIon of high-bulk-density detergent powders. For example, EP 158 419F (Hashimura) discloses a process in which nonionic surfactant and soda ash are mixed and granulated in a reactor having horizontal and vertical blades rn;ating at different speeds, to give a detergent powder built with sodium carbonate and containing a high level of nonionic surfactant.

GB 1 404 317 (Bell) discloses the preparation of a detergent powder of low or moderate bulk density by a dry neutralisation process. Detergent sulphonic acid is mixed with an excess of soda ash in the presence of sufficient water to initiate the neutralisation reaction but not enough to wet the resultant product, which is in the form of a free-flowing powder. The process is carried out in apparatus, for example a ribbon blender, planetary mixer or air transfer mixer, in which the reactants are "tossed and fluffed", and carbon dioxide liberated during the neutralisation is entrapped in the product particles. The process is thus directed towards the production of light, porous particles comparable to those obtained by spray-drying.

GB 1 369 269 (Colgate) discloses a process for the production of anionic detergent, by vigorously mixing detergent sulphonic acid with powdered sodium carbonate in a mixer with a cutting arrangement, for example a Lödige ploughshare mixer. In order to obtain a granular product rather than a doughy mass, it is necessary to blow the detergent sulphonic acid in by means of a gas stream, to ensure adequate fluidisation and mixing of the reactants: this requires quite complex modification of the mixer. No water is added to promote the neutralisation reaction, which therefore proceeds slowly and produces a relatively coarse product requiring an additional size reduction step. The temperature during neutralisation tvpically rises to about 85 C.

Us 4 690 785 (itco) discloses a process for the production of alkylbenzene sulphonate powder by the reugratisatior cf alkylbenzere sulphonic acid with a base in solid or solution form. A substantial amount of water is present at the beginning of the process, and the heat generated by the exothermic reaction is used to drive off this, and the water generated by the reaction itself; reaction temperatures of about 100 C are typical.

The present inventors have now discovered that free-flowing detergent powders and detergent powder components of high bulk density and small particle size can be produced by dry neutralisation at relatively low temperatures, using only a single piece of apparatus: a high-speed mixer/granulator having both a stirring action and a cutting action.

DEFINITION OF THE INVENTION The present invention accordingly provides a process for the preparation of a granular detergent composition or component having a bulk density of at least 650 litre, which process includes the step of neutralising a liquid acid precursor of an anionic surfactant with a solid water-soluble alkaline inorganic material, the process being characterised by the steps of:: (i) fluidising a particulate solid water-soluble alkaline inorganic material in an amount in excess of that required for neutralisation, optionally in admixture with one or more other particulate solids, in a high-speed mixer/ranulator having both a stirring action and 2 cutting action; (ii) gradually adding the acid precursor to the high-speed mixer/granulator, while maintaining a temperature not higher than 550C, whereby neutralisation of the acid precursor by the water-soluble alkaline inorganic material occurs while the mixture remains in particulate form; (iii) granulating the mixture in the high-speed mixer/granulator, in the presence of a liquid binder, whereby a granular detergent composition or component having a bulk density of at least 650 g/litre is formed.

The invention also provides a granular detergent composition or component prepared by this process.

DETAILED DESCRIPTION OF THE INVENTION The process DETAILED DESCRIPTION OF THE INVENTION The subject of the invention is the preparation of high-bulk-density detergent powder by a process involving the dry neutralisation of the acid precursor of an anionic surfactant with an alkaline solid. The process is carried out in a high-speed mixer/granulator and involves the previously defined process steps (i), (ii) and (iii).

A very important characteristic of the process of the invention is that the reaction mixture remains throughout in particulate or granular form. Caking, halling and dough formation are avoided, and the product at the end of the granulation step needs no further particle size reduction. The process of the invention generally produces a granular product containing at least 50 wtt, preferably at least 70 wt%, of particles smaller than 1700 microns. This is achieved by ensuring that liquid components, particularly the acid anionic surfactant precursor, do not have an opportunity to act as binders or agglomerating agents.

First, step (i) ensures that there is initially a large amount of particulate solids present, relative to the liquids to be added, in the mixer before the introduction of the liquids. Preferably the total solids present in step (i) amount to at least 60 wt%, more preferably at least 67 wt%, of the total composition present in step (ii). It is therefore advantageous to add as high a proportion as possible of the solid ingredients of the final product at this stage.

Preferably the liquids to solids ratio at the end of the neutralisation step (ii) does not exceed 0.60; more preferably it does not exceed 0.55, and desirably it does not exceed 0.50.

The solids must of course include a particulate water-soluble alkaline inorganic material (neutralising agent), in at least slight excess over the amount required for neutralisation. The terms "particulate solid water-soluble alkaline inorganic material" and "neutralising agent" used herein of course include combinations of two or more such materials. If the neutralising agent is a material that itself can play a useful role in the final composition, substantially larder amounts than this may be used.

According to a preferred embodiment of the invention the neutralising agent comprises sodium carbonate, either alone or in admixture with one or more other particulate water-soluble alkaline inorganic materials, for example, sodium bicarbonate and/or sodium silicate.

Sodium carbonate is of course also useful as a detergency builder and provider of alkalinity in the final composition. This embodiment of the invention may thus advantageously be used to prepare detergent powders in which sodium carbonate is the sole or principal builder, and in that case substantially more sodium carbonate than is required for neutralisation may be present.

The sodium carbonate embodiment of the invention is also suitable, however, for the preparation of detergent compositions in which substantial amounts of other builders are present. Those other builders may also advantageously be present in the high-speed mizer/granulator in step (i). Examples of such builders include crystalline and amorphous alkali metal aluminosilicates, alkali metal phosphates, and mixtures thereof. Sodium carbonate may nevertheless be present in excess of the amount required for neutralisation, in order to provide alkalinity in the product: an excess of about 10 to 15 wt% is then suitable.

The solids present in step (i) may also include any other desired solid ingredients, for example, fluorescers; polycarboxylate polymers; antiredeposition agents, for example, sodium carboxymethyl cellulose; fatty acids for in-situ neutralisation to form soaps; or fillers such as sodium sulphate, diatomaceous earth, calcite, kaolin or bentonite.

If desired, solid particulate surfactants, for example, alkylbenzene sulphonate and/or alkyl sulphate in powder form, may form part of the solids charge in step ('). Thus, for example, a detergent powder prepared by the process of the invention may contain alkylbenzene sulphonate in part introduced as a powder in step (i), and in part prepared in situ in step (ii).

Alternatively or additionally, a spray-dried detergent base powder may form part of the solids charge in step (i).

According to one preferred embodiment of the invention, the solids present in step (i) include a finely divided particulate flow aid. This is suitably present in an amount of from 2 to 8 wte, more preferably from 5 to 7 wt%, based on the final composition.

Suitable flow aids include crystalline or amorphous alkali metal aluminosilicate, thermally treated perlite, calcite, diatomaceous earth, and combinations of these.

Preferred flow aids are diatomaceous earth, and, in particular, Dicamol (Trade Mark) 424 thermally treated perlite. This material has a silica content of 80-87 wtt and a water absorbance capacity of 250-300 wt%. Its presence in the solids mix before and during the addition of the acid anionic surfactant precursor appears to assist in preventing excessive agglomeration and maintaining the reaction mix in particulate form.

It is an important feature of the process of the invention that the solids be very efficiently mixed and fluidised before the introduction of any liquid ingredients: the term "fluidisation1, as used herein means a state of mechanically induced vigorous agitation in which the mass of particles is to some extent aerated, but does not necessarily imply the blowing in of a gas.

This state is achieved by the choice of apparatus: a hi-speed mixer/granulator having both a stirring action and a cutting action. Preferably the high-speed mixer/granulator has rotatable stirrer and cutter elements that can be operated independently of one another, and at separately changeable or variable speeds.

Such a mixer is capable of combining a high-energy stirring input with a cutting action, but can also be used to provide other, gentler stirring regimes with or without the cutter in operation.

A preferred type of high-speed mixer/granulator for use in the process of the invention is bowl-shaped and preferably has a substantially vertical stirrer axis.

Especially preferred are mixers of the Fukae (Trade Mark) FS-G series manufactured by Fukae Powtech Kogyo Co., Japan; this apparatus is essentially in the form of a bowl-shaped vessel accessible via a top port, provided near its base with a stirrer having a substantially vertical axis, and a cutter positioned on a side wall.

The stirrer and cutter may be operated independently of one another, and at separately variable speeds. The vessel can be fitted with a cooling jacket or, if necessary, a cryogenic unit.

A similar mixer manufactured in India is the Sapphire (Trade Mark) RMG series of rapid mixer/granulator, which like the Fukae mixer is available in a range of different sizes. This apparatus is essentially in the form of a bowl-shaped vessel raised up pneumatically to seal against a fixed lid. A three-bladed stirrer and a four-bladed cutter share a single substantially vertical axis of rotation mounted on the lid. The stirrer and cutter may be operated independently of one another, the stirrer at speeds of '5 rrr or 150 rp, and the cutter at speeds of 1440 rprr or 2880 rpm. The vessel can be fitted with a cooling water jacket.

The Sapphire RMG-100 mixer, which is suitable for handling a 60 k batch of detergent powder, has a bowl of about 1 metre diameter and 0.3 metres deep; the working capacity is 200 litres. The stirrer blades are of 1 metre diameter and the cutter blades are of 0.1 metre diameter.

Other similar mixers found to be suitable for use in the process of the invention include the Diosna (Trade Mark) V series ex Dierks & Söhne, Germany; and the Pharma Matrix (Trade Mark) ex T K Fielder Ltd., England.

Other mixers believed to be suitable for use in the process of the invention are the Fuji (Trade Mark) VG-C series ex Fuji Sangyo Co., Japan; and the Roto (Trade Mark) ex Zanchetta & Co srl, Italy.

Yet another mixer found to be suitable for use in the process of the invention is the Lödige (Trade Mark) FM series batch mixer ex Morton Machine Co. Ltd., Scotland. This differs from the mixers mentioned above in that its stirrer has a horizontal axis. This configuration, however, has the disadvantage that mixing and fluidising in step (i) is less efficient, and may need to be supplemented by the blowing in of gas as described in the aforementioned GB 1 369 269 (Colgate).

The next stage of the process of the invention step (ii) - is the introduction of the acid surfactant precursor. The way in which this step is conducted is crucial to the success of the process. In particular, it is important that throughout the neutralisation step the amount of liquid present never rises to a level where it can cause substantial agglomeration.

It is believed, however, that the solids, now efficiently fluidised, have to be wetted with just sufficient water to initiate and promote the neutralisation reaction before they encounter the acid precursor. The amount of free water present in step (ii) is therefore believed to be very important. The term "free water" is used herein to mean water that is not firmly bound as water of hydration or crystallisation to inorganic materials. If insufficient is present, the reaction will not proceed rapidly, and unreacted detergent acid precursor will accumulate in the mixer and act as a binder, causing substantial agglomeration, balling up and even dough formation. Thus it would appear that enough water to wet all the solids should be present, but not so much that the water itself will act as a binder.

The solids themselves may contain sufficient free water for these conditions to be attained. For example, a spray-dried detergent base powder blown to a relatively high moisture content could provide most or all of the free water required. If insufficient free water is inherently present in the solids charge, a carefully controlled amount of water should be added either prior to or concurrently (together or separately) with the addition of the acid precursor. To ensure thorough wetting of the solids before the introduction of the acid precursor, all the water may be added before addition of the acid precursor commences. Alternatively, the acid precursor and the water may be introduced simultaneously into the mixer.

If desired, a small amount of water, sufficient to initiate the neutralisation reaction but not sufficient to cause substantial agglomeration, may be premixed with the acid precursor before the latter is introduced into the high-speed mixer/granulator. If a coloured product is desired, dyestuff may conveniently be premixed with the acid precursor and water before addition to the high-speed mixer/granulator.

The amount of water to be added will depend on the nature of the solids present. It has been found that an amount within the range of from 0.5 to 2.0 wt%, preferably from 0.5 to 1.5 wt%, based on the total solids present in steps (i) and (ii), gives good results in the preferred embodiment of the invention in which the neutralising agent is sodium carbonate.

Another important condition for step (ii) is that the acid precursor be added gradually, so that it will be consumed immediately and will not accumulate in the mixer in unreacted form. The time required and preferred for addition of the acid precursor is of course dependent on the amount to be added, but in general addition preferably takes place over a period of at least 1 minute, more preferably over a period of from 2 to 12 minutes, more preferably from 3 to 10 minutes.

Other liquid detergent ingredients may be introduced during step (ii). Examples of such ingredients include nonionic surfactants, and low-melting fatty acids which may be also be neutralised in situ, to form soaps.

The neutralisation step (ii) may typically take 2 to 12 minutes, and, as indicated above, the gradual addition of the acid precursor (optionally plus other liquid ingredients) may or may not be preceded b a separate step in which water (optionally plus other liquid ingredients) is added to the mixer.

As indicated previously, the temperature of the powder mass in the high-speed mixer/granulator should be maintained throughout step (ii) at 55 C or below, preferably below 50 C, more preferably below 47 0C, and desirably below 400C. A water jacket may be sufficient, for example, a jacket supplied with water at 25 0C is generally adequate to achieve temperatures below 470C; but in some cases it may be necessary to provide a cryogenic unit to inject cooling liquid or gas, for example, liquid nitrogen, into the mass of powder. If the temperature is allowed to rise, agglomeration and lump formation may occur.

A very important feature of the process of the invention is granulation in the high-speed mir/granulator. This will generally take the form of a separate granulation step (iii) after addition of the acid precursor and neutralisation are complete. If, however, addition of the liquids takes place over a relatively long period, granulation can occur before addition is complete, and then a separate granulation step (iii) may be unnecessary. In this case, steps (ii) and (iii) of the process may be regarded as having coalesced to form a single continuous step (ii)/(iii).

The granulation or densification process leads to a product of very high bulk density. Granulation in the process of the invention requires the presence of a liquid binder, but in an amount significantly lower than that used when granulating a powder in conventional apparatu such as a pan granulator: for example, from 3 to 8 wt% of the total composition, especially about 5 wtE, as compared to 10-15 wt%. The binder is added prior to granulation but after neutralisation is complete. 't ill generally comprise water and/or a liquid detergent ingredient, for example, an aqueous solution of a polycarboxylate polymer, or a nonionic surfactant, or a mixture of any of these.

In calculating the amount of binder required, it is important to take into account any free water already present in the composition and releasable at the process temperature, generally about 30-500C. For example, hydrated zeolite (which contains 27 moles of water per mole, or about 20 wt% of bound water) might be expected to release about 20 wt% of this (4 wt% of its total weight) at these temperatures; while sodium tripolyphosphate hexahydrate would probahly release little or no water.

It is believed that the total amount of free water that can be tolerated in the whole process is limited, and generally should not amount to more than 8 wt% of the total composition, preferably not more than 4 wti.

As with the water required for the neutralisation step (ii), sufficient free moisture for granulation may be available from the powder mass itself, and it may not be necessary to add a liquid binder.

The product of the granulation step (iii) is a particulate solid of high bulk density - at least 650 g/litre, preferably at least 750 g/litre, and more preferably at least 800 g/litre. As previously indicated, the particle size distribution is generally such that at least 50 wt%, preferably at least 70 wt% and more preferably at least 85 wt%, of particles are smaller than 1700 microns, and the level of fines is loll.

No further treatment has generally been found to be necessary to remove either oversize particles or fines.

If desired, further ingredients may be admixed to the granulated product of step (iii). For example, minor solid ingredients such as fluorescer and sodium carboxmethylcellulose may be added at this stage rather than included in the initial solids mix.

Although the product generally has good flow properties, low compressibility and little tendency towards caking, those powder properties may be improved further and bulk density further increased by the admixture of a builder salt or a finely divided particulate flow aid after granulation is complete.

A preferred builder salt that may be postdosed is sodium tripolyphosphate. This option is of especial interest for powders in which the principal or sole builder is sodium carbonate.

The flow aids mentioned above are also suitable for addition at this later stage in the process. Depending on the flow aid chosen, it may suitably be added in an amount of from 0.2 to 12.0 wt%, based on the total product.

Suitable flow aids include crystalline and amorphous alkali metal aluminosilicates having an average particle size within the range of from 0.1 to 20 microns, preferably from 1 to 10 microns. The crystalline material (zeolite) is preferably added in an amount of from 3.0 to 12.0 wt%, more preferably from 4.0 to 10.0 wit9, based on the total product. The amorphous rssseri l, which is more welght-effective, is preferably added in an amount of from 0.2 to 5.0 wt%, more preferably from 0.5 to 3.0 wt%, based on the total product. A suitable amorphous material is available commercial3.v from erosfield Chemicals ltd, Warrington, Cheshire, England, under the trade mark Alusil.If desired, both crystalline and amorphous aluminosilicates may be used, together or sequentially, as flow aids.

The other flow aids mentioned previously, namely, thermally treated perlite1 calcite, and diatomaceous earth, are also suitably used in amounts of from 0.2 to 5.0 wt, preferably from 0.5 to 3.0 wt%, based on the total product.

Yet other flow aids suitable for use in the process of the invention include precipitated silica, for example, Neosyl (Trade Mark), and precipitated calcium silicate, for example, Microcal (Trade Mark), both commercially available from Crosfield Chemicals Ltd.

A process which comprises admixing finely divided amorphous sodium aluminosilicate to a dense granular detergent composition containing surfactant and builder and prepared and/or densified in a high speed mixer/granulator is described and claimed in our copending European Patent Application No. 89 304205.1 filed on 27 April 1989.

The product As already indicated, the process of the invention produces a granular high-bulk-density solid, containing surfactant and builder, and having a bulk density of at least 650 g/litre and preferably at least 700 g/litre.

It is also characterised by an especially low particle porosity, preferably not exceeding 0.25 and more preferably not exceeding 0.2C, which distinguishes it from even the densest powders prepared by spray-drying.

This final granulate may be used as a complete detergent composition in its own right. Alternatively, it may be admixed with other components or mixtures prepared separately, and may form a major or minor part of a final product. Generally, any additional ingredients such as enzymes, bleach and perfume that are not suitable for undergoing the granulation process and the steps that precede it may be admixed to the granulate to make a final product. The densified granulate may typically constitute from 40 to 100 wt% of a final product.

In another embodiment of the invention, the densified granulate prepared in accordance with the present invention is an "adjunct" comprising a relatively high level of detergent-active material on an inorganic carrier; and this may be admixed in a minor amount with other ingredients to form a final product.

The process may with advantage be used to prepare detergent compositions containing from 5 to 45 wt%, especially from 5 to 35 wt%, of anionic surfactant, this anionic surfactant being derived wholly or in part from the in-situ neutralisation reaction of step (ii).

The process of the invention is of especial interest for the production of detergent powders or components containing relatively high levels of anionic surfactant, for example, 15 to 30 wte, more especially 20 to 30 wt%, but it is equally useful for the preparation of powders containing lower levels of anionic surfactant.

The bionic surfactant prepared at least in part by in-situ neutralisation may, for example, be selected from linear alkylbenzene sulphonates, alpha-olefin sulphonates, internal olefin sulphonates, fatty acid ester sulphonates and combinations thereof. The process of the invention is especially useful for producing compositions containing alkylbenzene sulphonates, by in-situ neutralisation of the corresponding alkylbenzene sulphonic acid.

Other anionic surfactants that may be present in compositions prepared by the process of the invention include primary and secondary alkyl sulphates, alkyl ether sulphates, and dialkyl sulphosuccinates. Anionic surfactants are of course well known and the skilled reader will be able to add to this list by reference to the standard textbooks on this subject.

If an especially high content of anionic surfactant in the final product is desired, additional anionic surfactant, in salt form (generally aqueous paste or solution) rather than in acid precursor form, may be added after granulation. In one preferred embodiment of the invention, the post-added anionic surfactant is alpha-olefin sulphonate. The possible addition of solid particulate anionic surfactant at an earlier stage in the process has already been mentioned. Thus the process of the invention represents a versatile route for incorporating high levels of anionic surfactant in powders of high bulk density.

As previously indicated, nonionic surfactants may also be present. These too are well known to those skilled in the art, and include primary and secondary alcohol ethoxylates.

Other types of non-soap surfactant, for example, cationic, zwitterionic, amphoteric or semipolar surfactants, may also be present if desired. 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.

If desired, soap may also be present, to provide foam control and additional detergency and builder power.

Typically, detergent compositions produced by the process of the invention may comprise from 10 to 35 wt% of anionic surfactant, from 0 to 10 wt% of nonionic surfactant, and from 0 to 5 wt% of fatty acid soap.

Typical products of the invention The following are general, non-limiting examples of formulation types that may readily be prepared by the process of the invention.

(1) Compositions comprising: (a) from 5 to 45 wt% of anionic surfactant, (b) from 20 to 70 wt% of inorganic builder salt comprising crystalline or amorphous alkali metal aluminosilicate, sodium tripolyphosphate, sodium crate, sodium silicate or any combination thereof, (c) from 0 to 20 wt of filler and/or flow aid comprising diatomaceos earth, silica, calc;te, sodium sulphate, bentonite, kaolin or any combination thereof, and optionally other detergent ingredients to 100 wt%.

In particular: (la) compositions containing sodium tripolyphosphate as the principal builder, and also containing sodium carbonate as neutralising alkali: (a) from 15 to 30 wt% of of anionic surfactant, (bl) from 10 to 60 wt% of sodium tripolyphosphate, (b2) from 5 to 60 wt% of sodium carbonate, (c) from 0 to 20 wtE of filler and/or flow aid comprising diatomaceous earth, silica, calcite, sodium sulphate, bentonite, kaolin or any combination thereof, and optionally other detergent ingredients to 100 wt%; and (lb) compositions containing sodium carbonate as the principal builder: (a) from 15 to 30 wt% of of anionic surfactant, (b) from 20 to 70 wt% of sodium carbonate, (c) from 0 to 20 wt% of filler and/or flow aid comprising diatomaceous earth, silica, calcite, sodiur: slphate, bentonite, kaolin or any combination thereof, and optionally other detergent ingredients to 100 wt%.

(2) Compositions containing crystalline or amorphous alkali metal aluminosilicate, especially crystalline zeolite and more especially zeolite 4A, as a detergency builder: (a) from 5 to 35 wt% of non-soap detergent-active material consisting at least partially of anionic surfactant, (b) from 15 to 45 wt% (anhydrous basis) of crystalline or amorphous alkali metal aluminosilicate, and optionally other detergent ingredients, including any excess of the neutralising agent for the anionic surfactant, to 100 wt%. The weight ratio of (b) to (a) is preferably at least 0.9:1.

An especially preferred class of detergent compositions that may be prepared by the process of the invention is described and claimed in our copending European Patent Application No. 89 304242.4 filed on 27 April 1989. These compositions comprise: (a) from 17 to 35 wtt of non-soap detergent-active material consisting at least partially of anionic surfactant, and (b) from 28 to 45 wt% of crystalline or amorphous alkali metal aluminosilicate, the weight ratio of (b) to (a) being from 0.9:1 to 2.6:1, preferably from 1.2:1 to 1.8:1, and optionally other detergent ingredients to 100 wt%.

(3) Compositions as described in our copending European Patent Application No. 89 304210.1 filed on 27 April 1989: (a) from 12 to 70 wt% of non-soap detergent-active material, and (b) at least 15 wt% of water-soluble crystalline inorganic salts, including sodium tripolyphosphate and/or sodium carbonate, the weight ratio of (b) to (a) being at least 0.4:1, preferably from 0.4:1 to 9:1 and more preferably from 0.4:1 to 5:1, and optionally other detergent components to 100 wt%.

These compositions preferably contain a total of from 15 to 70 wte of water-soluble crystalline inorganic salts, which may comprise, for example, sodium sulphate, sodium ortho- or pyrophosphate, or sodium meta- or orthosilicate. Especially preferred compositions contain from 15 to 50 wt, more preferably from 20 to 40 wt, of sodium tripolyphosphate.

As previously indicated, all these preferred classes of detergent composition that may be prepared by the process of the invention may contain conventional amounts cf other conver.tional ingredients, for exar.le, bleaches, enzymes, lather boosters or lather controllers as appropriate, antiredeposition and antiincrustation agents, perfumes, dyes and fluorescers. These may be incorporated in the product at any suitable stage, and the skilled detergent formulator will have no difficulty in deciding which ingredients are suitable for admixture in the high-speed mixer/granulator, and which are not.

The process of the invention has the advantage over conventional spray-drying processes that no elevated temperatures are involved, so fewer restrictions are imposed on the way in which heat-sensitive ingredients such as hleaches and enzymes are incorporated into the product.

The invention is further illustrated by the following non-limiting Examples, in which parts and percentages are by weight unless otherwise stated.

EXAMPLES Example 1 A 750 kg batch of high-bulk-density detergent powder having the following nominal formulation was prepared using a Fukae (Trade Mark) FS-1200 high-speed mixer/granulator: wt% Linear alkylbenzene sulphonate 25.0 Nonionic surfactant 2.0 Soap 1.0 Zeolite 4A (anhydr.) ) ( 35.0 Water with zeolite ) ( 9.99 So-* icate 4.0 Acrylate/maleate copolymer 1.0 Sodium sulphate 1.77 Fluorescer 0.18 Sodium carboxymethyl cellulose 0.9 Sodium carbonate 15.5 Total added water 2.0 Speckles 0.8 Enzyme 0.6 Perfume 0.25 100.00 The ratio of zeolite (anhydrous) to total non-soap surfactant in this composition was 1.29:1.

The process was carried out as follows: (i) Solid ingredients as specified below were dry-mixed in the Fukae mixer for 1 minute, using a stirrer speed of 100 rpm and a cutter speed of 2000 rpm.

parts Zeolite 4A (hydrated) 34.0 Sodium carbonate 19.53* Sodium carboxymethylcellulose 0.9 Sodium silicate 4.0 Acrylic/maleic copolymer 1.0 Flucrescer 0.9 Fattv acid 0.92 Total solids 61.25 *This amount of sodium carbonate represented a 4.9x excess ol-e- that required for neutralisation of the alkylbenzene sulphonic acid (see paragraph (ii) below).

(ii) Water (0.375 parts, = 0.61 wt% on total solids) was added, and the mixer was operated at the same stirrer and cutter speeds for 1 minute 30 seconds. Linear alkylbenzene sulphonic acid (23.5 parts) was added over a period of 5 minutes while the mixer was operated at a stirrer speed of 80 rpm and a cutter speed of 2000 rpm.

The temperature was maintained below 50 C by means of a cooling jacket filled with water. Throughout this step, the reaction mixture remained in particulate form.

Total liquids 23.88 Solids as % of total 71.95 The liquid : solid ratio at the end of step (ii) was 0.39.

(iii) When neutralisation was complete, binder in the form of further water (1.4 parts), and nonionic surfactant (2.0 parts), were added to the mixer, which was then operated for 3 minutes at a stirrer speed of 100 rpm and a cutter speed of 2000 rpm to effect granulation.

The temperature was maintained below 50 C hy means of a cooling jacket filled with water. The product of this step was a granular solid.

Total liquids 27.28 Solids as % of total 69.19 The liquid : solid ratio at the end of step (iii) was C.44.

(iv) Zeolite (a further 11 parts) was then added as a flol aid, while the mixer was operated for 2 minutes at a stirrer speed of 90 rpm with the cutter turned off.

The resulting powder was free-flowing, had a bulk density of 850 g/litre, and contained 73 wt% of particles < 1700 microns. The particle porosity was 0.15.

Coloured speckles of the same powder (0.8 parts) and enzyme granules (0.6 parts) were mixed with the powder using a rolling drum, and perfume (0.25 parts) were sprayed on, to give a fully formulated high-bulk-density detergent powder having excellent powder properties.

Example 2 The procedure of Example 1 was repeated, with the difference that the nonionic surfactant was added as a mixture with the acid, instead of during step (iii). A similar powder was obtained.

Example 3 The procedure of Example 1 was repeated, with the difference that 5 parts of zeolite were added to the mixer during step (iii), after addition of the binder but before granulation, and only 6 parts of zeolite were added as a flow aid in step (iv). A similar powder was obtained.

Example 4 The procedure of Example 2 was repeated, with the difference that half the anionic surfactant was added in step (i) as a powder (Marlon (Trade Mark) A390 ex Its).

A similar powder was obtained.

Example 5 This Example illustrates a procedure in which in-situ neutralisation is followed by the addition of a spray-dried base powder, and the mix is granulated together in the high-speed mixer/granulator.

A 750 kg batch of high-bulk-density detergent powder having the following nominal formulation was prepared using a Fukae (Trade Mark) FS-1200 high-speed mixer/granulator: parts I,inear alkylbenzene sulphonate 25.0 Nonionic surfactant 2.0 Soap 1.0 Zeolite 4A (anhydr.) ) ( 35.0 Water with zeolite ) ( 10.0 Sodium silicate 4.0 Acrylate/raleate copolymer 1.0 Sodium sulphate 1.8 Fluorescer 0.18 Sodium carboxymethyl cellulose 0.9 Sodium carbonate 15.5 96.4 The ratio of zeolite (anhydrous) to total non-soap surfactant in this composition was 1.29:1.

The process was carried out as follows: (i) Solid ingredients as specified below were dry-mixed in the Fukae mixer for 1 minute, using a stirrer speed of 100 rpm and a cutter speed of 2000 rpm.

kg Zeolite 4A (hydrated) 126 Sodium carbonate 93.1* Sodium carboxymethylcellulose 3.4 Sodium silicate 15.2 Acrylic/maleic copolymer 3.8 Fatty acid 3.5 Fluorescer 0.7 Total solids 245.7 *5.98x excess over amount required for neutralisation (ii) Water (3 kg, = 1.22 wt on total solids) was added, and the mixer was operated at a stirrer speed of 60 rpm and a cutter speed of 2000 rpm for 1 minute. The following liquid mix was then added over a period of 3 trinutes while the mixer was operated at the same stirrer and cutter speeds: Linear alkylbenzene sulphonic acid 89.1 Nonionic surfactant 11.4 Total liquids (including water) 103.5 The solids therefore represented 70.4 wtt of the liquids/solids mix during the neutralisation step.

The liquid : solid ratio at the end of the neutralisation step was 0.42. The temperature was maintained below 500C by means of a cooling jacket filled with water.

Throughout this step, the reaction mixture remained in particulate form.

(iii) When neutralisation was complete, a spray-dried base powder (336 kg) of the following formulation was added to the mixer: parts Linear alkylbenzene sulphonate 25.0 Nonionic surfactant 1.0 Soap 1.0 Zeolite 4A (anhydr.) ) ( 35.0 Water with zeolite ) ( 10.0 Sodium silicate 4.0 Acrylate/maleate copolymer 1.0 Sodium sulphate 1.8 Fluorescer 0.18 Sodium carboxymethl cellulose 0.9 Sodium carbonate 10.5 Water and the whole mix granulated for 4 minutes at a stirrer speed of 80 rpm and a cutter speed of 2000 rpm. The spray-dried powder contained sufficient free water, in addition to that added during step (ii), that no further addition of water as binder was necessary.

(iv) Zeolite (a further 60 kg) was then added as a flow aid, while the mixer was operated for 1 minute at a stirrer speed of 80 rpm with the cutter turned off.

The resulting powder was free-flowing, had a bulk density of 891 g/litre, and contained 80 wt% of particles < 1700 microns.

Examples 6 and 7 This pair of Examples illustrates the benefit of cooling with liquid nitrogen during the neutralisation step (ii).

Two 750 kg batches (Examples 6 and 7) of high-bulk-density detergent powder having the nominal formulation given in Example 5 was prepared using the Fukae FS-1200 high speed mixer/granulator. The process was carried out as follows: (i) Solid ingredients as specified below were dry-mixed in the Fukae mixer for 1 minute, using a stirrer speed of 100 rpm and a cutter speed of 2000 rpm.

kg Zeolite 4A (hydrated) 285 Sodium carbonate 148 Sodium carboxymethylcellulose 6.8 Sodium silicate 30.4 Acrylic/maleic copolymer 7.6 Fatty acid 7.0 Total solids 484.8 (ii) Water (6 kg, = 1.24 wt% on total solids) was added, and the mixer was operated at a stirrer speed of 75 rpm and a cutter speed of 2000 rpm for 1 minute. The following liquid mix was then added over 5 minutes while the mixer was operated at the same stirrer and cutter speeds: Linear alkylbenzene sulphonic acid 178 Nonionic surfactant 15 Total liquids (including water) 199 Solids as % of total 70.9 Liquid : solid ratio 0.41 After addition of the liquids was complete the mixer speeds were increased to 100 rpm/2000 rpm for 2 minutes.

For Example 6, the temperature was maintained below 35 C throughout the neutralisation step by spraying liquid nitrogen into the powder. For Example 7, the liquid nitrogen cooling was omitted, and the temperature rose to 52or. In both Examples, the reaction mixture remained in particulate form throughout the neutralisation step.

(iii) When neutralisation was complete, binder in the form of further water (6 kg) was added to the mixer at stirrer/cutter speeds of 80 rpm/2000 rpm, and the mixer was then operated for 3 minutes at the same stirrer and cutter speeds to effect granulation.

(iv) Zeolite (a further 57 kg) as a flow aid, and fluorescer (1.4 kg) were then added, while the mixer was operated for 1 minute at a stirrer speed of 80 rpm with the cutter turned off.

The powder of Example 6 was free-flowing, had a bulk density of 821 g/litre, and contained 81 wt% of particles < 1700 microns.

The powder of Example 7 was a product of similar bulk density but containing only 69 wt% of particles < 1700 microns.

Example 8 A 20 kg batch of high-bulk-density detergent powder having the following nominal formulation was prepared using a Fukae FS-30 high-speed mixer/granulator: wt% Linear alkylbenzene sulphonate 23.34 Nonionic surfactant 1.5 Soap 0.7 Zeolite 4A (anhydr.) ( 35.83 Water with zeolite ( 10.17 Sodium silicate 4.0 Acrylate/maleate copolymer 2.0 Sodium sulphate 1.72 Fluorescer 0.18 Sodium carboxymethyl cellulose 0.9 Sodium carbonate 15.0 Added water 2.0 Speckles 0.8 Enzyme 0.61 Perfume 0.25 Flow aid 1.0 100.00 The ratio of zeolite (anhydrous) to total non-soap surfactant in this composition was 1.44:1.

The process was carried out as follows: (i) Solid ingredients as specified below were dry-mixed in the Fukae mixer for 1 minute, using a stirrer speed of 300 rpm and a cutter speed of 3000 rpm.

parts Zeolite 4A (hydrated) 38.5 Sodium carbonate 18.72* Sodium carboxymethylcellulose 0.9 Sodium silicate 4.0 Total solids 62.12 *This amount of sodium carbonate represented an approximately 5x excess over the amount required for neutralisation of the alkylbenzene sulphonic acid and fatty acid (see paragraph (ii) below): the excess correspcnds te the 15.0 wt% present in the final formulation to provide alkalinity.

(ii) Water (0.375 parts, = 0.61 wt% on total solids) was added, and the mixer was operated at a stirrer speed cf ioe rpm and a cutter speed of 3000 rpm for 1 minute 30 seconds. The following liquid mixture was added over a period of 5 minutes while the mixer was in operation at the same stirrer and cutter speeds: parts Linear alkylbenzene sulphonic acid 21.85 Fattv acid 0.65 Nonionic surfactant 1.5 Total liquids 24.00 Solids as % of total 72.13 Liquid : solid ratio 0.39 The temperature was maintained below 50 C by means of a cooling jacket filled with water. Throughout this step, the reaction mixture remained in particulate form.

(iii) When neutralisation was complete, the following binder mixture was added: parts Water 1.0 Acrylic/maleic copolymer 2.0 Fluorescer 0.9 Total liquids 27.9 Solids as eO of total 69.0 Liquid : solid ratio 0.45 The mixer was then operated for 3 minutes at a stirrer speed of 300 rpm and a cutter speed of 300C rpm to effect granulation. The temperature was maintained below 50 C by means of a cooling jacket filled with water. The product of this step was a granular solid.

(iv) 7.5 parts of zeolite, and 1 part of amorphous sodium aluminosilicate (Alusil (Trade Mark) ex Crosfield Chemicals Ltd, 1 part) were then added as a flow aid, while the mixer was operated for 2 minutes at a stirrer speed of 90 rpm with the cutter turned off.

The resulting powder was free-flowing, had a bulk density of 830 g/litre, and contained 85 wt% of particles < 1700 microns.

Coloured speckles of the same powder (0.8 parts) and enzyme granules (0.61 parts) were mixed with the powder using a rolling drum, and perfume (0.25 parts) were sprayed on, to give a fully formulated high-bulk-density detergent powder having excellent powder properties.

Example 9 A 20 kg batch of high-bulk-density detergent powder built with sodium tripolyphosphate and sodium carbonate and having the following nominal formulation was prepared using a Fukae FS-30 high-speed mixer/granulator: parts Linear alkylbenzene sulphonate 32.0 Sodium tripolyphosphate 22.0 Sodium carbonate 40.0 Added water 2.0 Minor ingredients 0.7 Alusil flow aid 2.0 98.70 The ratio of crystalline water-soluble inorganic salts to total non-soap surfactant in this composition was 1.9:1.

In this formulation sodium carbonate was present as a major part of the building system. The sodium carbonate introduced during step (i) (see below) amounted to an approximately 8x excess over the amount required for neutralisation of the alkylbenzene sulphonic acid (see paragraph (ii) below).

The process was carried out as follows: (i) The solid ingredients were dry-mixed in the Fukae mixer for 1 minute, using a stirrer speed of 300 rpm and a cutter speed of 3000 rpm: parts Sodium carbonate 44.92 Sodium tripolyphosphate 22.0 Dry minor ingredients 0.7 Total solids 67.62 (ii) Water (2 parts) was added, and the mixer was operated at a stirrer speed of 100 rpm and a cutter speed of 3000 rpm for 1 minute. The linear alkylbenzene sulphonic acid (29.96 parts) was added over a period of 1 minute while the mixer was in operation at the same stirrer and cutter speeds. The temperature was maintained below 50 0C by means of a cooling jacket filled with water. Throughout this step, the reaction mixture remained in particulate form.

Total liquids 31.96 Solids as % of total 67.90 Liquid : solid ratio 0.47 (iii) When neutralisation was complete, binder in the form of further water (4.0 parts) was added to the mixer, while it was operated for 1 minute at a stirrer speed of 100 rpm and a cutter speed of 3000 rpm. The mixer was which was then operated for 4 minutes at a stirrer speed of 300 rpm and a cutter speed of 3000 rpm to effect granulation. The temperature was maintained below 50 C by means of a cooling jacket filled with water. The product of this step was a granular solid.

Total liquids 35.96 Solids as % of total 65.28 Liquid : solid ratio 0.53 (iv) Alusil (2 parts) was then added as a flow aid, while the mixer was operated for 1 minute at a stirrer speed of 90 rpm with the cutter turned off.

The resulting detergent powder was free-flowing, had a bulk density of 875 g/litre, and contained 75 wt% of particles < 1700 microns. Powder properties were excellent: dynamic flow rate was 133 ml/s and compressibility was 2% v/v.

Example 10 A 750kg batch of high-bulk-density detergent powder built with sodium tripolyphosphate and sodium carbonate and having the following nominal formulation was prepared using a Fukae FS-1200 high-speed mixer/granulator: wtE Linear alkylbenzene sulphonate 25.0 Soap 2.0 Sodium tripolyphosphate 38.0 Sodium silicate 5.0 Sodium carbonate 18.2 Sodium sulphate 6.6 Fluorescer 0.2 Alusil flow aid 3.0 Added water 2.0 100.0 The ratio of crystalline water-soluble inorganic salts to total non-soap surfactant in this composition was 2.5:1.

The process was carried out as follows: (i) The solid ingredients were dry-mixed in the Fukae mixer for 1 minute, using a stirrer speed of 100 rpm and a cutter speed of 1200 rpm.

Sodium carbonate 22.04 Sodium tripolyphosphate 38.0 Sodium sulphate 6.6 Dry minor ingredients 0.2 Total solids 66.84 (ii)/(iii) Water and alkylbenzenesulphonic acid were added over a period of 10 minutes while the mixer was operated at a stirrer speed of 35 rpm and a cutter speed of 1?OC rpm. The temperature was maintained at about 450C by means of a cooling jacket filled with water.

Because of the rather slow addition of the acid, it was found that granulation had occurred as soon as acid addition was complete. Thus no separate granulation step was required.

Water 0.8 Alkylbenzene sulphonic acid 23.4 Total liquids 24.2 Solids as % of total 73.41 Liquid : solid ratio 0.36 (iv) Alusil was added as a flow aid, while the mixer was operated for 1.5 minutes at a stirrer speed of 80 rpm and a cutter speed of 1200 rpm.

The resulting detergent powder was free-flowing, had the extremely high bulk density of 1050 g/litre, and contained about 70 wt% of particles < 1700 microns.

Dynamic flow rate was 71 ml/s and compressibility was 4.7% v/v.

Example 11 A 60 kg batch of high-bulk-density detergent powder having the following nominal formulation was prepared using a Sapphire (Trade Mark) RMG-100 high-speed mier/granulator: wt% Linear alkylbenzene sulphonate 29.0 Sodium tripolyphosphate 35.0 Sodium carbonate 20.0 Flow aid (Dicamol 424) 5.0 Sodium carboxymethylcellulose 1.5 Fluorescer (Photine C) 0.3 Plue dye (phthalocyanine) 0.1 Perfume 0.1 Flow aid (Dicamol 424) 1.0 Water3 5.0 Salts etc to 100.0 1 Added before neutralisation (see below) 2 Added after neutralisation (see below) 3 Added water about 1-1.5 wt%; the rest is from the raw materials and generated by the neutralisation reaction.

The process was carried out as follows: (i) Solid ingredients as specified below were dry-mixed in the Sapphire mixer for 1 minute, using a stirrer speed of 75 rpm and a cutter speed of 2880 rpm.

parts Sodium tripolyphosphate 35.0 Sodium carbonate 25.76* Flow aid (Dicamol 424) 5.0 *This amount of sodium carbonate represented a 4.47x excess over that required for neutralisation of the alkylbenzene sulphonic acid (see paragraph (ii) below).

(ii) A liquids premix was prepared by mixing 0.1 parts of phthalocyanine blue dye and 1.0 part water with a Silverson mixer, then mixing the resulting dye dispersion into 29.19 parts of alkylbenzene sulphonic acid of 93 wt% purity, also with the Silverson mixer.

The liquids premix was then added to the solids mix in the Sapphire mixer at a liquid to solid ratio of 0.47 over a period of 5 minutes while the mixer was operated at a stirrer speed of 75 rpm and a cutter speed of 2880 rpm. The temperature was maintained below 50 C by means of a cooling jacket filled and circulated with water at 25 0C. Throughout this step, the reaction mixture remained in particulate form.

(iii) When neutralisation was complete, the cutter speed was reduced to 1440 rpm while the stirrer speed remained at 75 rpm, and minor solids (sodium carboxymethyl cellulose, fluorescer) were added over a 1-minute period, together with further flow aid (Dicamol 424). The resulting mix was granulated for a further 1 minute at a stirrer speed of 75 rpm and a cutter speed of 2880 rpm. The material was then discharged over a 1-minute period with the cutter turned off and the stirrer running at 75 rpm.

The resulting powder was free-flowing, homogeneously blue coloured, had a bulk density of 800 g/litre, and contained 90 wt% of particles < 1700 microns. The mean particle size was 539 microns. Dynamic flow rate was 81.1 ml/s, and compressibility was 9.2% v/v.

mhe powder hac a rapid rate of dissolution comparable with the best high-bulk-density powders presently on the market: mire (seconds) Dissolution (wtiJ 0 64.9 15 78.5 20 86.1 25 89.5 A sample was examined by scanning electron micrography and was found to have a much more porous surface than a similar powder made without the addition of the flow aid Dicamol 424 to the initial solids mix.

Examples 12 to 14 These Examples illustrate the benefits of adding a flow aid (in this case calcite, Forcal (Trade Mark) U) during the initial stage - step (i) - of the process.

Three 60 kg batches of high-bulk-density detergent powder having the following nominal formulation was prepared using a Sapphire (Trade Mark) RMG-100 high-speed mixer/granulator: wt% Linear alkylbenzene sulphonate 29.0 Sodium tripolyphosphate 35.0 Sodium carbonate 20.0 Flow aid see below Sodium carboxnethylcellulose 1.5 Fluorescer (Photine C) 0.3 Blue dye (phthalocyanine) 0.1 Perfume 0.1 Water 5.0 Salts etc to 100.0 The powders were prepared generally as described in Example 1, with the following differences relating to the addition of flow aid: Before After neutralisation neutralisation Example 12: 5 parts Forcal U 2 parts Dicamol 424 Example 13: - 5 parts Forcal U after part neutralisation; 1.5 parts Dicamol 424 after neutralisation complete.

Example 14: - 5 parts Forcal U 1 part Dicamol 424 The liquid to solid ratios at the end of the neutralisation step in these Examples were therefore 0.55, 0.57 and 0.60 respectively.

A11 three powders were free-flowing, homogeneously blue coloured, and had bulk densities areater than 700 g/litre. Other powder properties were as follows: 12 13 14 Yield < 1700 microns (wt%) 90.3 81.2 83.1 Average particle size (yam) 607 709 699 Dynamic flow rate (ml/s) 120 120 125 Bulk density (g/l) 765 780 800 Dissolution (wt%): after 10 sec 56.5 33.8 27.7 after 30 sec 71.4 49.7 47.8 These results show that the sequence of addition used in Example 12 gave a powder with a smaller average particle size and a superior rate of dissolution.

Examples 15 to 19 These Examples show the effects of different flow aids added before neutralisation.

60 kg batches of powder were prepared by the general procedure used in previous Examples, but using different amounts of different flow aid as follows: Example Liauid: Flow aid in Flow aid in solid step (i) step (ii) 15 0.55 zeolite (5 parts) Dicamol (1 part) 16 0.49 Dicamol (5 parts) 17 0.53 Forcal U (5 parts) Dicamol (2 parts) 18 0.51 Filtroseem (5 pts) Dicamol (1.5 pts) 19 0.56 Dicamol (5 parts) Dicamol (1 part) Powder properties are shown in the following table.

It will be seen that Example 19 gave the best combination of properties.

15 16 17 Bulk density (g/litre) 730 736 720 Yield < 1700 microns (wt%) 82.5 90.0 85.0 Average particle size (yin) 723 539 640 Dynamic flow rate (ml/s) 110 81 100 Compressibility (%v/v) 10.5 10.0 15.8 Dissolution (wt%): after 15 sec 38.3 64.9 43.9 after 30 sec 58.2 78.5 63.7 18 19 Bulk density (g/litre) 751 736 Yield < 1700 microns (wt%) 85.6 86.3 Average particle size (pm) 536 560 Dynamic flow rate (ml/s) 115 115 Compressibility (Ev/v) 11.8 11.0 Dissolution (wt%): after 15 sec 55.4 58.8 after 30 sec 74.6 78.2 Examples 20 to 22 The general procedure of earlier Examples was repeated, but to give powders containing a mixed surfactant system of alkylbenzene sulphonate (prepared by neutralisation) and alpha-olefin sulphonate (post-added as 4 wt% aqueous solution).The formulations were as follows: 20 21 22 Alkylbenzene sulphonate 26.1 26.1 22.7 Olefin sulphonate 2.9 2.9 5.0 Sodium tripolyphosphate 35.0 35.0 32.0 Sodium carbonate 20.0 20.0 20.0 Flow aid (Dicamol) 1 5.0 5.0 Flow aid (calcite) 1 - - 2.0 SCYC 1.5 1.5 1.5 Fluorescer 0.3 0.3 0.3 Perfume 0.1 0.1 0.1 Flow aid (Dicamol) 2 1.0 0.5 2.0 Salts, water etc to 100.0 100.0 100.0 1 Added before neutralisation Added after neutralisation The powder properties of Examples 20 and 21, as shown in the following table, were not significantly different from those of Example 19. The powder of Example 22 had a higher bulk density but inferior flow properties.

20 21 22 Bulk density (g/litre) 780 780 830 Yield < 1700 microns (wt%) 87.1 84.3 89.8 Average particle size ( m) 527 578 443 Dynamic flow rate (ml/s) 100 103 67 Compressibility (%v/v) 12.6 13.8 Dissolution (wt%): after 15 sec 58.9 48.5 after 30 sec 75.7 68.3 77.7 Examples 23 to 25 The general procedure of earlier Examples was used to prepare sodium tripolyphosphate-built detergent powders having the following formulations: 23 24 25 Alkylbenzene sulphonate 29.8 25.1 24.3 Sodium tripolyphosphate 52.0 20.0 35.0 Sodium carbonate 8.0 45.0 25.0 Flow aid (calcite)1 - 2.0 5.0 SCMC 1.5 1.5 1.5 Fluorescer (Photine C) 0.3 0.3 0.3 Perfume 0.1 0.1 0.1 Flow aid (Dicamol 424) - 2.0 2.0 P::3 t ey , salts etc to 100.0 100.0 100.0 Liquid:solid ratio 0.60 0.42 0.45 Added before neutralisation 2 Added after neutralisation Powder properties were as follows: 23 24 25 Bulk density (g/litre) 800 800 830 Yield < 1700 microns (wt%) 84.0 93.3 89.4 Dynamic flow rate (ml/s) 85 80 120 Average particle size (yam) 742 455 Examples 26 to 29 The general procedure of earlier Examples was used to produce 60 kg batches of sodium carbonate-built powders to the formulations shown below. In Examples 27 and 28, the alpha-olefin sulphonate was post-added in the form of 70 wt% paste; in Example 29 it was added as 40 wt% solution, after neutralisation but before the addition of the greater part of the calcite.

26 27 Linear alkylbenzene sulphonate 19.0 18.9 klpha-olefirs sulphonate - 5.0 Sodium carbonate 67.0 61.0 Flow aid (calcite) 4.0 4.0 SCMC 1.5 1.5 Flucrescer (Photire C) 0.2 0.2 Perfume 0.1 0.1 Flow aid (Dicamol 424) 2.0 2.0 Water, salts etc to 100.0 100.0 Liquid:solid ratio 0.36 0.50 28 29 Linear alkylbenzene sulphonate 20.7 22.5 Alpha-olefin sulphonate 5.0 2.5 Sodium carbonate 62.0 58.0 Flow aid (calcite) 4.0 5.0 SCMC 1.5 1.5 Fluorescer (Photine C) 0.2 0.2 Perfume 0.1 0.1 Flow aid (Dicamol 424) 2.0 2.0 Water, salts etc to 100.0 100.0 Liquid:solid ratio 0.50 0.44 Powder properties were as follows: : 26 27 Rulk density (g/litre) 800 800 Yield < 1700 microns (wt%) 93.7 95.7 Dynamic flow rate (ml/s) 37.5* 70.0 Average particle size (m) - 507 *It waC found that the poor flow properties of the powder of Example 16 could be substantially improved by postdosing a small amount of sodium tripolyphosphate: 7.5 wt STP improved the dynamic flow rate to 55.5 ml/s; 15.0 wtE STP improved the dynamic flow rate to 60.0 ml/s.

28 29 Bulk density (g/litre) 880 796 Yield < 1700 microns (wt%) 92.8 90.0 Dynamic flow rate (ml/s) 75 92 Compressibility (t v/v) - 13.2 Average particle size (calm) 491 268

Claims (1)

1. CLAIMS 1. A process for the preparation of a granular detergent composition or component having a bulk density of at least 650 g/litre, which process includes the step of neutralising a liquid acid precursor of an anionic surfactant with a solid water-soluble alkaline inorganic material, the process being characterised by the steps of:: (i) fluidising a particulate solid water-soluble alkaline inorganic material in an amount in excess of that required for neutralisation, optionally in admixture with one or more other particulate solids, in a high-speed mixer/granulator having both a stirring action and a cutting action; (ii) gradually adding the acid precursor to the hich-speed mixer/granulator while maintaining a temperature rot higher than 55 0C, whereby neutralisation of the acid precursor by the water-soluble alkaline inorganic material occurs while the mixture remains in particulate form; (iii) granulating the mixture in the high-speed mioer/granulator, in the presence of a liquid binder, whereby a granular detergent composition or component having a bulk density of at least 650 g/litre is formed.

   2. A process as claimed in claim 1, wherein the granular detergent composition or component formed in step (iii) contains at least 50 wt% of particles smaller than 1700 microns.

   3. A process as claimed in claim 2, wherein the granular detergent composition or component formed in step (iii) contains at least 70 wt% of particles smaller than 1700 microns.

   4. A process as claimed in any preceding claim, wherein the particulate water-soluble alkaline inorganic material comprises sodium carbonate.

   5. A process as claimed in claim 4, wherein the particulate water-soluble alkaline inorganic material comprises sodium carbonate in admixture with sodium hicarbonate and/or sodium silicate.

   6. A process as claimed in any preceding claim, wherein the liquids to solids ratio at the end of step (ii) is not greater than 0.60.

   7. A process as claimed in claim 6, wherein the liquids to solids ratio at the end of step (ii) is not greater than 0.55.

   8. A process as claimed in claim 7, wherein the liquids to solids ratio at the end of step (ii) is not greater than 0.50.

   9. A process as claimed in any preceding claim, wherein the acid precursor is a linear alkylbenzene sulphonic acid.

   10. A process as claimed in any preceding claim, wherein in step (ii) the acid precursor is added over a period of at least 1 minute.

   11. A process as claimed in claim 10, wherein in step (ii) the acid precursor is added over a period of from 2 to 12 minutes.

   12. A process as claimed in any preceding claim, wherein water is introduced prior to or together with the acid precursor in step (ii).

   13. A process as claimed in claim 12, wherein the amount of water added in step (ii! is within the range of from 0.5 to 2.0 wt% based on the total solids present in steps (i) and (ii).

   14. A process as claimed in claim 13, wherein the amount of water added in step (ii) is within the range of from 0.5 to 1.5 wt% based on the total solids present in steps (i) and (ii) 15. A process as claimed in any one of claims 12 to 14, wherein water is admixed with the acid precursor prior to its addition to the high-speed mixer/granulator in step (ii) 16. A process as claimed in claim 15, wherein water and colour are admixed with the acid precursor prior to its addition to the high-speed mixer/granulator.

   17. A process as claimed in any preceding claims, wherein one or more other liquid detergent ingredients are introduced into the high-speed mixer/granulator during step (ii).

   18. A process as claimed in claim 17, wherein nonionic surfactant and/or fatty acid is or are introduced into the high-speed mixer/granulator during step (ii).

   19. A process as claimed in any preceding claim, wherein the solids present in step (i) comprise the water-soluble alkaline inorganic material in admixture with one or more detergency builders.

   20. A process as claimed in claim 19, wherein the solids present in step (i) comprise sodium carbonate in admixture with one or more detergency builders selected from crystalline and amorphous alkali metal aluminosilicates, alkali metal phosphates, and mixtures thereof.

   21. A process as claimed in any preceding claim, wherein the solids present in step (i) further comprise one or more solid detergent ingredients selected from fluorescers, polycarboxylate polymers, antiredeposition agents, and fatty acids.

   22. A process as claimed in any preceding claim, wherein the solids present in step (i) further include a surfactant in powder form.

   23. A process as claimed in claim 22, wherein the surfactant in powder form comprises alkylbenzene sulphonate and/or alkyl sulphate.

   24. A process as claimed in any preceding claim, wherein the solids present in step (i) include a spray-dried detergent base powder.

   25. A process as claimed in any preceding claim, wherein the particulate solids present during step (i) include a finel divided particulate flow aid.

   26. A process as claimed in claim 25, wherein the flow aid is added in an amount of from 2 to 8 wt%, based on the final composition.

   27. A process as claimed in claim 26, wherein the flow aid is added in an amount of from 5 to 7 wt%, based on the final composition.

   28. A process as claimed in any one of claims 25 to 27, wherein the flow aid is zeolite, amorphous alkali metal aluminosilicate, thermally treated perlite, calcite, diatomaceous earth or any combination of these.

   29. A process as claimed in any preceding claim, wherein the total solids present in step (i) amount to at least 60 wti of the total composition present in step (ii).

   30. A process as claimed in claim 29, wherein the total solids present in step (i) amount to at least 67 wt% of the total composition present in step (ii).

   31. A process as claimed in any preceding claim, wherein the liquid binder present in step (iii) comprises water and/or one or more liquid detergent ingredients.

   32. A process as claimed in claim 31, wherein the liquid binder present in step (iii) is selected from water, aqueous solutions of polycarboxylate polymers, nonionic surfactants, and mixtures thereof.

   33. A process as claimed in any preceding claim, wherein the total amount of free water present in steps (i), (ii) and (iii) does not exceed 8 wt%, based on the total composition.

   34. A process as claimed in claim 33, wherein the total amount of free water present in steps (i), (ii) and (iii) does not exceed 4 wt, based on the total composition.

   35. A process as claimed in any preceding claim, wherein the temperature in the high-speed mixer/granulator is maintained below 47 0C throughout step (ii).

   36. A process as claimed in claim 35, wherein the temperature in the high-speed mixer/granulator is maintained below OOC throughout step (ii).

   37. A process as claimed in any preceding claim, wherein the high-speed miser/granulator is bowl-shaped and has a substantially vertical stirrer axis.

   38. A process as claimed in any preceding claim, which further comprises the step of admixing a finely divided particulate flow aid to the granular detergent composition or component after the granulation step (iii) is complete.

   39. A process as claimed in claim 38, wherein the flow aid is finely divided crystalline or amorphous alkali metal aluminosilicate, thermally treated perlite, calcite, diatomaceous earth or any combination of these.

   40. A process as claimed in claim 38 or claim 39, wherein the flow aid is added in an amount of from 0.2 to 12.0 wtE, based on the final composition.

   41. A process as claimed in any one of claims 38 to 40, wherein the flow aid is finely divided amorphous sodium aluminosilicate, thermally treated perlite, calcite, diatomaceous earth or a combination thereof, and is added in an amount of from 0.2 to 5.0 wt%, based on the total composition.

   42. A process as claimed in any one of claims 38 to 40, wherein the flow aid is finely divided crystalline sodium aluminosilicate and is added in an amount of from 3.0 to 12.0 wt%, based on the total composition.

   43. A process as claimed in any preceding claim, wherein further anionic surfactant is added after step (iii).

   44. A process as claimed in claim 43, wherein the further anionic surfactant comprises olefin sulphonate.

   45. A process as claimed in any preceding claim, wherein a builder salt is postdosed to the composition after step (iii) 46. A process as claimed in claim 45, wherein the builder salt comprises sodium tripolyphosphate.

   47. A process as claimed in claim 1, carried out substantially as hereinbefore described in any one of Examples 1 to 29.

   48. A granular detergent composition or component therefor, having a bulk density of at least 650 g/litre, prepared by a process as claimed in any preceding claim.

   49. A detergent composition or component as claimed in claim 48, having a bulk density of at least 750 g/litre.

   50. A detergent composition or component as claimed in claim 48 or claim 49, containing at least 50 wt% of particles smaller than 1700 microns.

   51. A detergent composition or component as claimed in claim 50, containing at least 70 wt% of particles smaller than 1700 microns.

   52. A detergent composition or component as claimed in any one of claims 48 to 51, which comprises from 5 to 45 wt% of anionic surfactant.

   53. A detergent composition or component as claimed in claim 52, which comprises from 5 to 35 wt% of anionic surfactant.

   5G. A detergent composition or component as claimed in claim 53, which comprises from 10 to 35 wt% of anionic surfactant, from 0 to 10 azt% of nonionic surfactant, and from 0 to 5 wtE of fatty acid soap, 55. A detergent composition or component as claimed in claim 53, which comprises from 15 to 30 wt% of anionic surfactant.

   56. A detergent composition or component as claimed in claim 55, which comprises from 20 to 30 wt% of anionic surfactant.

   5?. A detergent composition or component as claimed in any one of claims 48 to 56, which comprises one or more anionic surfactants selected from alkylbenzene sulphonates, alpha-olefin sulphonates, internal olefin sulphonates, fatty acid ester sulphonates and combinations thereof.

   58. A detergent composition or component as claimed in any one of claims 48 to 51, which comprises: (a) from 5 to 35 wt% of non-soap detergent-active material consisting at least partially of anionic surfactant, (b) from 15 to 45 wt% (anhydrous basis) of crystalline or amorphous alkali metal aluminosilicate, and optionally other detergent ingredients to 100 wt%.

   59. A detergent composition or component as claimed in claim 58, wherein the ratio of (b) to (a) is at least 0.9:1.

   60. A detergent composition or component as claimed in any one of claims 48 to 51, which comprises: (a) from 17 to 35 wt% of non-soap detergent-active material consisting at least partially of anionic surfactant, and (b) from 28 to 45 wt% of crystalline or amorphous alkali metal aluminosilicate, the weight ratio of (b) to (a) being from 0.9:1 to 2.6:1, and optionally other detergent ingredients to 100 wti.

   61. A detergent composition or component as claimed in claim 60, wherein the ratio of (b) to (a) is within the range of from 1.2:1 to 1.8:1.

   62. A detergent composition or component as claimed in any one of claims t S to 51, which comprises: (x) from 12 to 70 wt of non-soap detergent-active material, and (y) at least 15 wt% of water-soluble crystalline inorganic salts, including sodium tripolyphosphate and/or sodium carbonate, the weight ratio of (y) to (x) being at least 0.4:1, and optionally other detergent ingredients to 100 wt%.

   63. A detergent composition or component as claimed in claim 62, wherein the weight ratio of (y) to (x) is within the range of from 0.4:1 to 9:1.

   64. A detergent composition or component as claimed in claim 63, wherein the weight ratio of (y) te (x) is within the range of from 0.4:1 to 5:1.

   65. A detergent composition or component as claimed in any one of claims 48 to 51, which comprises: (a) from 5 to 45 wtZ of of anionic surfactant, (b) from 20 to 70 wt% of inorganic builder salt comprising crystalline or amorphous alkali metal aluminosilicate, sodium tripolyphosphate, sodium carbonate, sodium silicate or any combination thereof, (c) from 0 to 20 wt% of filler and/or flow aid comprising diatomaceous earth, silica, calcite, sodium sulphate, bentonite, kaolin or any combination thereof, and optionally other detergent ingredients to 100 wt.

   66. A detergent composition or component as claimed in claim 65, which comprises: (a) from 15 to 30 wt% of of anionic surfactant, (bl) from 10 to 60 wt% of sodium tripolyphosphate, (b2) from 5 to 60 wt of sodium carbonate, (c) from 0 to 20 wt% of filler and/or flow aid comprising diatomaceous earth, silica, calcite, sodium sulphate, bentonite, kaolin or any combination thereof, and optionally other detergent ingredients to 100 wt%.

   67. A detergent composition or component as claimed in claim 65, which comprises: (a) from 15 to 30 wt% of of anionic surfactant, (b) from 20 to 70 wt% of sodium carbonate, (c) from 0 to 20 wt% of filler and/or flow aid comprising diatomaceous earth, silica, calcite, sodium sulphate, bentonite, kaolin or any combination thereof, and optionally other detergent ingredients to 100 wt%.

   68. A detergent composition as claimed in claim 48, substantially as hereinbefore described in any one of Examples 1 to 29.