AU611555B2

AU611555B2 - Process for preparing detergent compositions

Info

Publication number: AU611555B2
Application number: AU33749/89A
Authority: AU
Inventors: Robert Donaldson; Andrew Timothy Hight; Michael William Hollingsworth; Keiichi Kawafuchi; Donald Peter; Peter John Russell
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 1988-04-29
Filing date: 1989-04-27
Publication date: 1991-06-13
Anticipated expiration: 2009-04-27
Also published as: EP0339996B1; JPH0715119B2; KR920000113B1; ES2043009T3; AU3374989A; KR890016153A; DE68907438T2; MY104968A; BR8902005A; HK47894A; CA1323277C; JPH0249100A; EP0339996A1; TR25924A; PH25538A; DE68907438D1

Description

27 Sf,.~A AUSTRALIA 1 PATENTS ACT 1952 Form COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE Short Title: Int. C1: Application Number: Lodged:

I

Complete Specification-Lodged: Accepted: Lapsed: Published: S' Priority: S Related Art: a. TO BE COMPLETED BY APPLICANT Name of Applicant: Address of Applicant: UNILEVER PLC UNILEVER HOUSE

BLACKFRIARS

LONDON EC4

ENGLAND

Actual Inventor: Address for Service: a-- 6 0 GRIFFITH HACK CO., 601 St. Kilda Road, Melbourne, Victoria 3004, Australia.

Complete Specification for the invention entitled: PROCESS FOR PREPARING DETERGENT

COMPOSITIONS.

The following statement is a full description of this invention including the best method of performing it known to me:- L- a S1989 atLondon Englandrthis day of Mqrrhb 19 DECLARED at 0 0 1 1 1 1 d a y o

L--

a c

I

I 5 TECHNICAL FIELD 00 The presen preparing granu: density having properties.

0 o e• o 1 C.3236 PROCESS FOR PREPARING DETERGENT COMPOSITIONS t invention relates to a process for lar detergent compositions of high bulk good washing performance and good powder BACKGROUND AND PRIOR ART 00*000

I

0 0O 0 I Recently there has been considerable interest within the detergents industry in the production of detergent powders having relatively high bulk density, for example, 600 g/litre and above. Particular attention has been paid to the densification of spray-dried powders by post-treatment. For example, GB 1 517 713 (Unilever) discloses a process in which a detergent powder produced by spray-drying or pan granulation is spheronised and granulated in a "marumerizer" (Trade Mark) with some increase in bulk density.

T

CLEMENT HACK CO.

2 C.3236 EP 229 671A (Kao) discloses a process in which a spray-dried detergent powder containing surfactant and builder is subjected successively to pulverising and granulating treatments in a high-speed mixer/granulator, the granulation being carried out in the presence of an "agent for improving surface properties" and optionally a binder. In the Examples, the agent for improving surface properties is zeolite 4A (10 parts), used together with water (2 parts) as binder. After granulation, a further 3 parts of zeolite 4A are admixed with the product.

JP 84 041680B (Kao) describes a process in which a nn spray-dried detergent base powder is pulverised, mixed 15 with powdery granules, having a crystallinity of 0-100% and a particle size of 0.1-300 microns, of sodium aluminosilicate, calcium silicate, calcium carbonate, magnesium silicate or sodium carbonate, and simultaneously or subsequently mixed with a tackifying substance, for example, a nonionic surfactant, alkyl ether sulphate or higher alcohol.

EP 220 024A (Procter Gamble) discloses a process 9 for the densification of a spray-dried powder containing 25 a high level (30-85 wt%) of anionic surfactant.

The powder is compacted and granulated, inorganic builder (sodium tripolyphosphate, or crystalline sodium aluminosilicate and sodium carbonate) being added before Scompaction and/or after granulation.

The present inventors have now discovered that detergent compositions of high bulk density and excellent flow properties can be prepared by granulating a spray-dried or dry-mixed detergent base powder in a -~uun a a a a n~lh fl"nn 11" 3 C.3236 high-speed mixer/granulator and then admixing a small amount of finely divided amorphous aluminosilicate after granulation is complete. The amorphous material is substantially more weight-effective than crystalline zeolite for this purpose.

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 g/litre, which comprises the steps of: 15 treating a particulate material comprising one or more non-soap detergent-active compounds and one or more inorganic builders in a high-speed mixer/granulator having both a stirring action and a cutting action, in the presence of a liquid binder, whereby granulation and densification to a bulk density of at least 650 g/litre are effected, (ii) admixing finely divided amorphous sodium aluminosilicate to the granular material obtained in 25 step DETAILED DESCRIPTION OF THE INVENTION The process In the process of the invention, a particulate starting material (detergent base powder) prepared by any suitable method is treated in a high-speed 4 C.3236 mixer/granulator to increase its bulk density and simultaneously to improve its powder properties. The process of the invention provides a route for the production of very dense granular detergent compositions having excellent cleaning performance and good powder properties.

In the process of the invention, granulation is effected by means of a high-speed mixer/granulator having both a stirring action and a cutting action. Preferably the stirrer and cutter may be operated independently of one another and at separately variable speeds. Such a mixer is capable of combining a high energy stirring input with a cutting action, but can also be used to 15 provide other, gentler stirring regimes with or without Sthe cutter in operation. It is thus a highly versatile and flexible piece of apparatus.

o..

S A preferred type of high-speed mixer/granulator for S" 20 use in the process of the invention is bowl-shaped and preferably has a substantially vertical stirrer axis.

I Especially preferred are mixers of the Fukae (Trade Mark) FS-G series manufactured by Fukae Powtech Kogyo Co., Japan; this appar&tus is essentially in the form of a 25 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.

Other similar mixers found to be suitable for use in the process of the invention are the Diosna (Trade Mark) V series ex Dierks S8hne, Germany; and the Pharma Matrix (Trade Mark) ex T K Fielder Ltd., England. Other similar mixers believed to be suitable for use in the i ,i 5 C.3236 process of the invention include the Fuji (Trade Mark) VG-C series ex Fuji Sangvo Co., Japan; and the Roto (Trade Mark) ex Zanchetta Co sri, Italy.

Another mixer found to be suitable for use in the process of the invention is the Lbdige (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.

As indicated above, the use of a high-speed mixer/granulator is essential in the process of the invention to effect granulation and densification. If desired, the mixer may also be used for a pretreatment step before granulation is carried out.

For example, it is within the scope of the *9* invention for the particulate starting material to be "I prepared at least in part by mixing in the high-speed mixer/granulator. Thus, a dry-mixed starting powder may be prepared from its raw materials in the high-speed mixer/granulator; or one or more further ingredients may be admixed with an otherwise premixed powder prepared elsewhere (for example, by spray-drying). A suitable stirring/cutting regime and residence time may be chosen in accordance with the materials to be mixed.

.Another possible pretreatment that may be carried out in the high-speed mixer/granulator is pulverisation; 30 whether or not this is necessary depends, among other things, on the method of preparation of the starting powder and its free moisture content. Powders prepared by spray-drying, for example, are more likely to require pulverisation than powders prepared by dry-mixing.

Again, the flexibility of the apparatus allows a suitable I 1 6 C.3236 stirring/cutting regime to be chosen: generally relatively high speeds for both stirrer and cutter. A relatively short residence time (for example, 2-4 minutes for a 35 kg batch) is generally sufficient.

An essential feature of the process of the invention is the granulation step, during which densification to the very high values of at least 650 g/litre, preferably at least 700 g/litre occurs, giving a dense, granular product of very uniform particle size and generally spherical particle shape.

Granulation is effected by running the mixer at a relatively high speed using both stirrer and cutter; a 15 relatively short residence time (for example, 5-8 minutes for a 35 kg batch) is generally sufficient. The final 4o** bulk density can be controlled by choice of residence time, and it has been found that the powder properties of the resulting granulate are not optimum unless the bulk S 20 density has been allowed to rise to at least 650 g/litre.

The presence of a liquid binder is necessary for e successful granulation. The amount of binder added preferably does not exceed that needed to bring the free 25 moisture content of the composition above about 6 wt%, since higher levels may lead to a deterioration in the flow properties of the final granulate. If necessary, binder, preferably water, may be added before or during granulation, but some starting powders will inherently 4 30 contain sufficient moisture. If a liquid binder is to be added, it may be sprayed in while the mixer is running. In one preferred mode of operation, the mixer I is first operated at a relatively slow speed while binder is added, before increasing the speed of the mixer to effect granulation.

7 C.3236 If the starting powder has a sufficient free moisture content to render the addition of a binder unnecessary, pulverisation (if required) and granulation need not be regarded as separate process steps but as one single operation. Indeed, it is not, in that case, necessary to decide in advance whether or not pulverisation is required: the mixer may simply be allowed to do what is necessary, since the mixer conditions required are generally substantially the same for pulverisation and for granulation.

In accordance with the invention, finely divided amorphous sodium aluminosilicate is admixed with the granular material after granulation is complete.

15 Advantageously, the amorphous sodium aluminosilicate is added while the granulate is still in the high-speed mixer/granulator, and the mixer is operated at a slow speed for a further short period. No further granulation occurs at this stage. It is also within the scope of the invention to add the amorphous sodium aluminosilicate to the granulate after removing the latter to different apparatus.

9 The granulation stage is preferably carried out at a 25 controlled temperature somewhat above ambient, preferably above 30 C. The optimum temperature is apparently formulation-dependent, but appears generally to lie within the range of from 30 to 45 C, preferably about 35 C. This temperature may also be maintained during _30 the admixture of the finely divided amorphous sodium aluminosilicate.

I;

L p-U 8 C.3236 The amorphous sodium aluminosilicate The amorphous sodium aluminosilicate used in the process of the present invention is a finely divided particulate material. The preferred average particle size is 0.1 to 20 microns, more preferably 1 to microns. A suitable material is available commercially from Crosfield Chemicals Ltd, Warrington, Cheshire, under the trade mark Alusil.

The amorphous sodium aluminosilicate is advantageously used in an amount of from 0.2 to 5.0 wt%, based on the starting powder, more preferably from 0.5 to 3.0 wt%.

This material is effective even at very low levels in improving flow properties, and also has the effect of increasing bulk density. It is therefore possible to adjust bulk density by appropriate choice of the level of S 20 amorphous aluminosilicate added after granulation.

The amorphous material used in the process of the invention should be distinguisbed from zeolite (hydrated crystalline sodium aluminosilicate) which is 25 substantially less weight-effective in the context of the present invention. Substantially higher levels than those quoted above are needed before any comparable flow The starting powder The process of the invention may be used to densify and improve any detergent powder prepared by any tower or non-tower method, for example, spray-drying or dry fslsla~ rnl ~L l 9 C.3236 mixing. If desired, the particulate starting material may be prepared at least partially by mixing in the high-speed mixer/granulator itself. The particulate starting material may consist at least partially of a spray-dried powder.

The process of the invention has been found to give especially satisfactory results with detergent base powders containing low to moderate levels of surfactant and relatively high levels of inorganic builder.

According to a first preferred embodiment of the invention, the process is used for the preparation of high-bulk-density powders containing substantial levels 15 of sodium aluminosilicate builder. These powders preferably contain not more than 5 wt% of phosphate builders, and are more preferably substantially free of phosphate builders.

9* S 20 Thus a preferred starting powder might comprise: from 5 to 35 wt% of non-soap detergent-active material, and 25 from 28 to 45 wt% (anhydrous basis) of crystalline or amorphous sodium aluminosilicate, the weight ratio of to being at least 0.9:1, and optionally other detergent components to 100 wt%.

The process of the invention is outstandingly suitable for preparing the high-bulk-density powders, containing moderate levels of surfactant and high levels of zeolite, described and claimed in our copending application of even date (Case C.3235). These powders comprise: fi 10 C.3236 from 17 to 35 wt% of non-soap detergent-active material consisting at least partially of anionic detergent-active material, and from 28 to 45 wt% (anhydrous basis) of crystalline or amorphous sodium aluminosilicate, the weight ratio of to being from 0.9:1 to 2.6:1, and optionally other detergent components to 100 wt%.

The aluminosilicate builder present in the starting powder may be crystalline or amorphous or a mixture thereof, and has the general formula 15 0.8-1.5 Na20.Al203 0.8-6 SiO 2 These materials contain some bound water and are required to have a calcium ion exchange capacity of at least about 50 mg CaO/g. The preferred aluminosilicates 20 contain 1.5-3.5 SiO 2 units (in the formula above) and have a particle size of not more than about 100 microns, S preferably not more than about 20 microns. Both S amorphous and crystalline aluminosilicates can be made readily by reaction between sodium silicate and sodium 25 aluminate, as amply described in the literature.

Crystalline aluminosilicates (zeolites) are preferred in the low- or zero-phosphate starting powders treated by the process of the present invention.

30 Suitable materials are described, for example, in GB 1 473 201 (Henkel) and GB 1 429 143 (Procter Gamble). The preferred sodium aluminosilicates of this type are the well-known commercially available zeolites A and X, and mixtures thereof. Type 4A zeolite is especially preferred.

ii 11 C.3236 The ratio of aluminosilicate builder (anhydrous basis) to total non-soap surfactant in the starting powder is preferably within the range of from 1.2:1 to 1.8:1.

According to a second preferred embodiment of the invention, the process is used for the preparation of high-bulk-density powders containing substantial levels of water-soluble inorganic salts, including sodium tripolyphosphate and/or sodium carbonate, as described and claimed in our copending application of even date (Case C.3261).

Thus a preferred starting powder might comprise: S from 12 to 70 wt% of non-soap detergent-active material, and 2(y) at least 15 wt% of water-soluble inorganic salts, including sodium tripolyphosphate and/or sodium carbonate, the weiaht ratio of to being at least 0.4:1, and optionally other detergent components to 100 wt%.

Preferably the weight ratio of to is within the range of from 0.4:1 to 9:1, more preferably from 1:1 to 9:1. An especially preferred starting powder contains from 15 to 70 wt% of water-soluble inorganic 30 salts, more preferably from 15 to 50 wt%, especially from to 40 wt%, of sodium tripolyphosphate.

In both the first and second preferred embodiments of the invention, the non-soap surfactant present in the starting powder preferably consists at least partially of .4 a cutting action, Inl Li 11 co= binder, whereby granulation and densification to yield a granular material with a bulk density of at least 650 g/litre are effected, /2 12 C.3236 anionic surfactant. Suitable anionic surfactants will be well known to those skilled in the art, and include linear alkylbenzene sulphonates, particularly sodium linear alkylbenzenesulphonates having an alkyl chain length of C -C 1 5 primary and secondary alkyl sulphates, particularly sodium C 1 2

-C

1 5 primary alcohol sulphates; alkyl ether sulphates; alpha-olefin and internal olefin sulphonates; alkane sulphonates; dialkyi sulphosuccinates; fatty acid ester sulphonates; and combinations thereof.

If desired, the starting powder may contdin nonionic surfactant. Nonionic surfactants too will be well known to those skilled in the art, and include primary and 15 secondary alcohol ethoxylates, especially the C12-C15 .primary and secondary alcohols ethoxylated with an average of from 3 to 20 moles of ethylene oxide per mole of alcohol.

20 Suitably the surfactant component of the starting powder may be constituted by from 0 to preferably from 8 to 60% by weight, of anionic surfactant, and from 0 to 20%, preferably from 0 to by weight of nonionic surfactant.

IOther types of non-soap surfactant, for example, cationic, mwitterionic, amphoteric or semipolar surfactants, may also be present if desired. Many S.suitable detergent-active compounds are available and are S* 30 fully described in the literature, for example, in "Surface-Active Agents and Detergents", Volumes I and II, by Schwartz, Perry and Berch.

A-

13 C.3236 If desired, soap may also be present, to provide foam control and additional detergency and builder power; soap is not included in the figures for the surfactant content quoted previously.

The final granulate has 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, not exceeding 0.25 and preferably not exceeding 0.20, which distinguishes it from even the densest powders prepared by spray-drying alone.

The final granulate may be used as a complete detergent composition in its own right. Alternatively, 15 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 S" not suitable for undergoing the granulation process may be admixed to the granulate to make a final product.

A detergent base powder may, for example, be prepared by spray-drying an aqueous slurry of i *heat-insensitive and compatible ingredients; if 25 desired, other ingredients may then be admixed; and the I resulting powder densified and granulated in accordance with the present invention. Yet further ingredients may .if desired be admixed after granulation; the densified Sf granulate may typically constitute from 40 to 100 wt% of 30 a final product.

Alternatively, a detergent base porder may be prepared by dry mixing one or more raw materials and/or one or more premixes of raw materials, in the high-speed mixer/granulator itself or in other apparatus, and then oQ~ I -Y -3C--lrrr_ awa~ 14 C.3236 densified and granulated in accordance with the present invention. Again, further ingredients may if desired be added after granulation.

Yet again, the granulate prepared in accordance with the present invention may be 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 invention is further illustrated by the following non-limiting Examples, in which parts and percentages are by weight unless otherwise stated.

0 *0 *0S U o p *•o S 94 Pe, GB 1 517 713 (Unilever) discloses a process in which a detergent powder produced by spray-drying or pan granulation is spheronised and granulated in a "marumerizer" (Trade Mark) with some increase in bulk density.

15 C.3236

EXAMPLES

Example 1 A detergent composition having a bulk density of 350 g/litre was prepared to the following composition by spray-drying an aqueous slurry: 4444 .4 4 4 Oe .4 44 4 4 4 44 Linear alkylbenzene sulphonate Nonionic surfactant Soap Zeolite (anhydr.) Water with zeolite Sodium silicate Sodium succinate Acrylate/maleate copolymer Sodium sulphate Sodium carbonate Minor ingredients Free moisture 20.0 35.0 10.0 10.45 10.0 1.55 100.0 '4 *4 I *44 44 4 9 4 It will be noted that the ratio of zeolite 30 (anhydrous) to non-soap surfactant in this composition was 1.59.

excellent flow properties can be prepared by granulating a spray-dried or dry-mixed detergent base powder in a 9~ 16 C.3236 kg of this spray-dried powder were introduced into a Fukae (Trade Mark) FS-G series high-speed mixer/granulator, and pulverised at high speed (stirrer 180 rpm, cutter 3013 rpm) for 4 minutes at 32 0 C. Water (500 g, was then sprayed in over a period of min while the mixer was allowed to run at a slower speed (stirrer 100 rpm, cutter 3000 rpm) at a temperature of 0 C. The mixer was then allowed to run at an stirrer speed of 140 rpm, a cutter speed of 2700 rpm and a temperature of 36-37 C to effect granulation.

After granulation was complete, Alusil (Trade Mark) fine amorphous sodium aluminosilicate (250 g, was introduced into the Fukae mixer, which was then operated 15 at a slow speed (stirrer 90 rpm, cutter 300 rpm) for 1 minute. The resulting granular product was free-flowing and showed no tendency to cake. Its properties, and those of a sample removed before the *e 4.

S* 'addition of the Alusil, are shown in Table 1 below.

It will be noted that the final mean particle size after Alusil addition was slightly smaller than before t the addition of the Alusil, showing that a minor amount of dearanulation had occurred during this treatment.

Surprisingly, however, the percentage of fine particles had decreased. The substantial increase in bulk density effected by the addition of Alusil will be noted.

f~I 51W iy ILCaLc :L±at u :eergent nase powder) prepared by any suitable method is treated in a high-speed 17 Table 1 C.3236 Before Alusil addition After Alusil addition Bulk density (g/l) Mean particle size (microns) Dynamic flow rate (ml/s) Fines (wt% of particles <180 microns) 794 785 892 704 120 8

I

4. sap 4, .4 a 0o 0S 4.

I

.4.4.4 4. 1* a 4. 4.E

S.

a Particle porosity <0.20 <0.20 Examples 2 3, Comparative Examples A B In these Examples, the effect of adding Alusil after granulation was compared with the effect of adding crystalline zeolite 4A after granulation. Samples of the spray-dried powder used in Example 1 were treated in 25 the Fukae mixer as described in that Example, Alusil or zeolite as shown in Table 2 below being added after granulation was complete.

V series ex Dierks S8hne, Germany; and the Pharma Matrix (Trade Mark) ex T K Fielder Ltd., England. Other similar mixers believed to be suitable for use in the Io r- 18 C.3236 Table 2 Example Flow aid (wt Alusil Zeolite Bulk density (g/l) Dynamic flow rate (ml/s) 15 Particle size (microns) 1.0 856 92.3 507 11 1.7 854 92.3 546 8 1.0 740 33.5 530 2 784 42.5 529 1 *c S 0S IgoS *0 8 OS ma 5009 a ao 0 me 0:0% *see r Fines content (wt% <180 microns) The large differences in both bulk density and dynamic flow rate will be noted.

Example 4 This Example describes the preparation of a complete 30 detergent product using the process of the invention.

A detergent composition was prepared to the following composition by spray-drying an aqueous slurry to a free moisture content of substantially zero: m ww ml 19 C.3236 parts Linear alkylbenzene sulphonate 24.0 Nonionic surfactant Soap Zeolite (anhydr.) 38.0 Water with zeolite 10.84 Sodium silicate Acrylate/maleata copolymer Minor ingredients Sodium carbonate 10.0 94.64 It will be noted that the ratio of zeolite (anhydrous) to non-soap surfactant in this composition .was 1.46.

20 35 kg of this spray-dried powder were introduced into a Fukae (Trade Mark) FS-G series high-speed mixer/granulator, and pulverised at high speed for 2-4 minutes. The mixer was then stopped, water (2.0 parts) was sprayed in, and the mixer was then restarted at a 25 slower speed and allowed to run for 5-8 minutes v'hile the temperature was maintained at about 35 C; during this period granulation occurred.

A sample of the granular product was removed from 30 the Fukae mixer. It was free-flowing and showed no tendency to cake. Its dynamic flow rate was 65 ml/s.

C,

is first operated at a relatively slow speed while binder is added, before increasing the speed of the mixer to effect granulation.

I II-- I L 20 C.3236 part of Alusil (Trade Mark) fine amorphous sodium aluminosilicate was introduced into the Fukae mixer, which was then operated at a slow speed for 1 minute. The resulting granular product was free-flowing and showed no tendency to cake. Its bulk density was 740 g/litre and its particle porosity was less than 0.20.

Its mean particle size was 405 microns, and its dynamic flow rate was 105 ml/s.

.0 The following ingredients were then mixed with the granular material to give 100 parts of final detergent powder: @9

C,

r'

C,

*r

C,.

.9 C,

C,.

Coloured speckles Enzyme (alcalase) Perfume 1.5 parts 0.61 parts 0.25 parts Example 5, Comparative Example C 35 kg of the spray-dried powder used in Example 4 were introduced into a Ldige (Trade Mark) FM series high-speed mixer/granulator, and pulverised for 4 25 minutes. Water (1.1 kg, was then sprayed in while the mixer continued to run at the same speed, then the mixer was allowed to run for a further 3 minutes while the temperature was maintained at about 35 C. During this period granulation occurred. A sample (Comparative Example C) was removed from the mixer and its properties are shown in Table 3 below.

I u

X~

21 C.3236 Alusil (Trade Mark) finely divided amorphous sodium aluminosilicate (1.2 kg) was then introduced into the mixer which was allowed to run for a further 0.5 minutes.

The properties of the resulting powder (Example 5) are shown in Table 3 below, from which the benefits of adding a flow aid after granulation is complete are apparent.

The presence of the Alusil did result in an increase in the content of fine particles <180 microns, but not to an unacceptable level.

Comparative Example D 28.8 kg of the spray-dried powder used in Example 4 were introduced into a L8dige (Trade Mark) FM series high-speed mixer/granulator, and pulverised for 4 'minutes. Alusil (Trade Mark) finely divided amorphous sodium aluminosilicate (1.2 kg) was then introduced into the mixer. Water (1.1 kg, was sprayed in while the mixer continued to run, then the mixer was allowed to run for a further 3 minutes while the temperature was maintained at about 35 C. During this period granulation *.occurred. The properties of the resulting powder are e shown in Table 3 below, from which the detrimental effect 25 of addiing Alusil before granulation are apparent. It will be noted that the increase in fines content is significantly greater when the Alusil is added before granulation.

The process of the invention may be used to densify and improve any detergent powder prepared by any tower or non-tower method, for example, spray-drying or dry r r 22 Table 3 C.3236 Example Bulk density (g/l) Dynamic flow rate (ml/s) Particle size (microns) -0 Fines content (wt% of particles <180 microns)

C

680 100 573 5 754 109 524

D

704 59 424 Particle porosity <0.20 <0.20 not measured 0 9* S. 0

S

S.

Comparative Example E The procedure of Comparative Example D was repeated, but the Alusil was added before the pulverisation step instead of after it. Pulverisation and granulation were carried out as in previous Examples, but the resulting product had a dynamic flow rate of zero.

Example 6, Comparative Example F

S.

S

s*

S.

S

20 kg of the spray-dried powder used in Example 4 30 were introduced into a Fukae (Trade Mark) high-speed mixer/granulator, and pulverised for 4 minutes. Water (0.8 kg) was then added and the mixture granulated over a period of 4 minutes, while the temperature was maintained at about 35 C. A sample (Comparative Example F) was removed from the mixer and its powder properties determined: these are shown in Tablei below.

23 C.3236 Alusil (Trade Mark) finely divided amorphous sodium aluminosilicate (0.2 kg) was then admixed. The physical properties of the resulting powder (Example 6) are shown in Table~s below; the results were similar to those ob'tcine.A jbt-ia&ne in Examples4* and C using the L8dige mixer.

Comparative Example G 20 kg of the spray-dried powder used in Example 4 were introduced into the Fukae high-speed mixer/granulator, and pulverised for 4 minutes. Alusil (Trade Mark) finely divided amorphous sodium aluminosilicate (0.2 kg) was then introduced into the mixer. Water (0.8 kg) was then added and the mixture granulated over a period of 4 minutes, while the temperature was maintained at about 35 C. Physical properties of the resulting powder are shown in Table.4 below: the results were similar to those obtained using the LBdige mixer (Comparative Example D).

9S 9 9* 9.

9*

A

tcype are tne weii-iknown commercially availanle zeoiites a and X, and mixtures thereof. Type 4A zeolite is especially preferred.

muflp in 4 24 4 C. 3236 -1- Example Bulk density (g/1) Dynamic flow rate (ml/s) Particle size (microns) Fines content (wt% of particles 180 microns) Particle porosity 688 109 550 0 0.1 740 120 480 10 0.1 670 380 22 not measured

S

t S* S

S.

S

S..

S.

S

S. 55 S S

S

*5S* S S S. S 55

S

555

S

S *SS S S

S.

In both the first and second preferred embodiments of the invention, the non-soap surfactant present in the starting powder preferably consists at least partially of 25 C.3236 Example 7, Comparative Example H These Examples involved a process in which a powder prepared by dry-mixing was densified and granulated in a high-speed mixer/granulator. The following formulation was prepared by mixing in a concrete mixer: parts Linear alkylbenzene sulphonate 24.0 Nonionic surfactant Soap Zeolite (anhydr.) 38.0 Water bound with zeolite 10.84 Sodium carbonate (light soda ash) 10.0 Sodium silicate Acrylate/maleate copolymer Minor ingredients 0 P* 20 92.21 0o 00 The ratio of aluminosilicate to non-soap surfactant in this mixture was 1.46.

0 0 25 20 kg of this formulation were placed in a Diosna (Trade Mark) V100 mixer aand mixed for 1 minute at a stirrer speed of 196 rpm and a cutter speed of 3000 rpm.

Water (0.2 kg) was added over a period of 2 minutes while the mixer was operated at a stirrer speed of 98 rpm and a 30 cutter speed of 1500 rpm, then the mixture was granulated for 4 minutes at a stirrer speed of 196 rpm and a cutter speed of 3000 rpm. A sample (Comparative Example H) was removed and its powder properties measured (see below).

Finally Alusil (0.2 kg) was mixed in while the mixer was operated at a stirrer speed of 98 rpm with the cutter switched off; and the powder properties of the final granulate (Example 7) were also measured.

26 C.3236 The powder properties of the granulate before and after the addition of Alusil were as follows: H 7 Bulk density 750 810 Dynamic flow rate (ml/s) 80 96 Compressibility 17.0 15.3 Particle size (microns) 607 Particle porosity <0.20 <0.20 0 Example 8, Comparative Example J 2 A detergent powder built with sodium S 20 tripolyphosphate was prepared by spray-drying an aqueous S• slurry to the following formulation: wt 25 Linear alkylbenzene sulphonate 9.7 Nonionic surfactant 2.8 Soap 4.9 Sodium tripolyphosphate 42.5 Sodium sulphate 14.8 S 30 Sodium silicate 10.0 Minor ingredients 2.8 Water 12.5 100.0 27 C.3236 The ratio of water-soluble crystalline inorganic salts (sodium tripolyphosphate and sodium sulphate) to non-soap surfactant was 4.6:1.

Two separate 20 kg batches of this powder were densified in the Fukae mixer, as follows. The powder was initially subjected to a 2-3 minute warming-up period, with the stirrer running at 50 rpm and with the cutter switched off, until the temperature had reached about 30-35 0 C. Pulverisation for 0.5 minutes at a stirrer speed of 180 rpm and a cutter speed of 1000 rpm followed; water (0.5 wt%) was added over 0.5 minutes while the mixer was operated at a stirrer speed of 100 rpm and a cutter speed of 3000 rpm; then granulation was 15 carried out for 6 minutes at a stirrer speed of 140 rpm and a cutter speed of 3000 rpm.

R To the first sample (Example Alusil (1.5 wt% :C was added over a period of 1 minute while the mixer was 20 operated at a stirrer speed of 90 rpm and a cutter speed of 300 rpm.

To the second sample (Comparative Example J), c* zeolite (5 wt%) was added over the same period of time 25 and under the same mixer conditions.

Powder properties were as follows: S Yield <1700 microns 93 97 Average particle size (microns) 555 480 Bulk density (g/litre) 840 780 Dynamic flow rate (ml/s) 92 61 Compressibility 7 12 Particle porosity <0.20 <0.20 mrarsl- ~lur 28 C.3236 Example 9, Comparative Example K This Example illustrates the sequential addition of zeolite and Alusil to a densified powder.

A detergent base powder was prepared to the following composition by spray-drying an aqueous slurry to a free moisture content of substantially zero: parts Linear alkylbenzene sulphonate 24.0 Nonionic surfactant Soap Zeolite 4A (anhydrous) 27.27 Water with zeolite 7.73 Sodium silicate Acrylate/maleate copolymer Minor ingredients 2.85 S 20 Sodium carbonate 16.51 The weight ratio of anhydrous zeolite to non-soap detergent in this base powder was 1.05:1.

S 25 90 parts of this base powder were granulated and densified in the Fukae mixer as described in previous Examples, then a further 10 parts (hydrated basis) of zeolite 4A were admixed. A sample (Comparative Example K) was removed, and then Alusil (0.4 parts) was added to 30 give a final granulate (Example 9).

.IV

A

I

I «rt MM 1 29 C.3236 The powder properties are shown below, and demonstrate that the final addition of Alusil, in the small quantity of 0.5 parts to 100, effected significant increases in bulk density and flow rate, and decreases in cohesiveness and caking, even though 10 parts of zeolite had already been postdosed.

K 9 Bulk density, g/l 732 760 Dynamic flow rate, ml/s 85 98 Powder cohesiveness 10 9 Powder caking after storage in cartons for 6 months 10 *c 20 Particle porosity <0.20 <0.20

D

*p p p *p

Claims

1. A process for the preparation of a granular detergent composition or component having a bulk density of at least 650 g/litre and a particle porosity not exceeding 0.25 which comprises the steps of: treating a particulate material comprising one or more non-soap detergent-active compounds and 0 one or more inorganic builders in a high-speed mixer/granulator having both a stirring action and a cutting action, in the presence of a liquid binder, whereby granulation and densification to yield a granular material with a bulk density of at least 650 g/litre are effected, (ii) subsequently to the densification, admixing finely divided amorphous sodium aluminosilicate to the granular material obtained in step b S. 59 S S

2. A process as claimed in claim 1, wherein tne finely divided amorphous sodium aluminosilicate is added in an amount of from 0.2 to 5.0 wt%, based on the particulate material treated in step *S 5 55

3. A process as claimed in claim 1 or claim 2, wherein the finely divided amorphous sodium aluminosilicate is 30 added in an amount of from 0.5 to 3.0 wt%, based on the particulate material. S. S. 0. a 55 S

4. A process as claimed in any preceding claim, wherein 35 step (ii) is also carried out in the high-speed mixer/granulator. 31 C.3236 GB A process as claimed in any preceding claim, wherein granulation is carried out in a bowl-type high-speed mixer/granulator having a substantially vertical stirrer axis.

6. A process as claimed in any preceding claim, wherein the particulate starting material consists at least partially of spray-dried powder.

7. A process as claimed in any preceding claim, wherein the particulate starting material is prepared at least in part by mixing in the high-speed mixer/granulator prior to granulation.

8. A process as claimed in any preceding claim, wherein the particulate starting material is pulverised in the ji 9. A process as claimed in any preceding claim, wherein a liquid binder is added to the composition in the high-speed mixer/granulator before granulation. A process as claimed in any preceding claim, wherein granulation is carried out at a temperature of at least 30 30 'C.

11. A process as claimed in claim 10, wherein granulation is carried out at a temperature within the range of from 30 to 45 0 C. 32 C.3236 GB

12. A process as claimed in any preceding claim, wherein granulation effects an increase in bulk density to at least 700 g/litre.

13. A process as claimed in any preceding claim, wherein the particulate starting material comprises: from 5 to 35 wt% of non-soap detergent-active material and from 28 to 45 wt% (anhydrous basis) of crystalline or amorphous sodium aluminosilicate, 15 the weight ratio of to being at least 0.9:1, and optionally other detergent components to 100 wt%. ta e* 14. A process as claimed in claim 13, wherein the 20 particulate starting material comprises: from 17 to 35 wt% of non-soap p l detergent-active material consisting at least Spartially of anionic detergent-active material, and from 28 to 45 wt% (anhydrous basis) of crystalline or amorphous sodium aluminosilicate, the weight ratio of to being from 0.9:1 to 2.6:1, 30 and optionally other detergent components to 100 wt%. A process as claimed in claim 13 or claim 14, wherein the aluminosilicate in the particulate starting material is a crystalline zeolite. I 33 C.3236 GB

16. A process as claimed in claim 15, wherein the aluminosilicate in the particulate starting material is Type 4A zeolite.

17. A process as claimed in any one of the preceding claims, wherein the particulate starting material comprises from 15 to 70 wt% of crystalline inorganic salts including sodium tripolyphosphate and/or sodium carbonate.

18. A process as claimed in claim 17, wherein the particulate starting material comprises from 15 to 50 wt% of sodium tripolyphosphate. 9 9. 9 9 *9 9 9 9 9**99 9 9. 99

19. A process substantially as hereinbefore described in any one of Examples 1 to 9.

20. A granular detergent composition or component whenever prepared by a process as claimed in any one of claims 1 to 19. DATED THIS 26TH DAY OF MARCH 1991 UNILEVER PLC By its Patent Attorneys: GRIFFITH HACK CO. Fellows Institute of Patent Attorneys of Australia. 9. 9. 9* 9 i