NO302621B1 - Particulate detergent composition, as well as process for its preparation - Google Patents

Abstract

A particulate high-density detergent composition having excellent flow properties comprises 15 to 50 wt% of a high-performance surfactant system - selected ethoxylated alcohol nonionic surfactant plus optionally a minor amount of primary alkyl sulphate - and from 20 to 60 wt% of zeolite. The ethoxylated nonionic surfactant preferably has a peaked ethoxylation distribution, and the zeolite may advantageously be maximum aluminium zeolite P. The composition is preferably prepared by an agglomeration process utilising a high-speed mixer/granulator.

Description

The invention relates to particulate detergent mixtures which combine exceptionally good cleaning performance with high bulk density and excellent powder properties. The mixtures contain a high level of high-performance organic surfactant - selected ethoxylated alcohol and optionally a small amount of alkyl sulfate - and zeolite detergency builder, and are produced by an agglomeration process, where a high-speed mixer/granulator is used.

The trend regarding washing powder has recently gone in the direction of increased spatial density, e.g. over 600 g/l. These high-density or "concentrated" powders have been produced by various processes, some of which involve post-densification of a spray-dried powder, and others based on dry-mixing, agglomeration or other processes, completely "non-tower", which does not take place in the tower.

The trend towards higher densities, and therefore inherently less porous particles, has made the incorporation of high levels of mobile organic ingredients without loss of powder flow properties more difficult. However, it has become highly desirable to improve detergency performance by incorporating higher levels of surfactant, and by using surfactants that have the greatest possible effectiveness against oil and grease soiling. One class of such surfactants consists of ethoxylated alcohols with a relatively low degree of ethoxylation, and these are generally mobile liquids at ambient temperature.

Against the background of increasing environmental awareness, it has also become desirable to use alkyl sulphates in favor of the linear alkylbenzene sulphonates which are traditionally used in laundry detergents. Alkyl sulphates are easily biodegradable and can be obtained from renewable sources, e.g. coconut and palm oil. However, they are generally more difficult to process into high-quality washing powders than the alkylbenzene sulphonates.

Nonionic surfactants, alkyl sulfates, and mixtures of the two have been shown to provide highly effective detergency, but because of their mobility, they are difficult to incorporate, even at moderate levels, into free-flowing powders that will disperse in the wash bath. When higher proportions of these surfactants are required to push detergency performance to even higher levels, these difficulties would be expected to increase, and to be exacerbated even more in the highly concentrated, dense powders frequently preferred by the consumer and the detergent industry.

However, we have succeeded in formulating high bulk density free-flowing washing powders that combine excellent performance with good powder properties and dispersibility, despite containing relatively high levels of high-performance mobile surfactants. The powders according to the invention contain relatively high levels of zeolite builder and can be produced by a granulation process in a high-speed mixer/granulator. Particularly good powder properties can be achieved by using a new zeolite P which builds; and particularly good detergency can be achieved by using selected non-ionic surfactants.

EP 265 203A discloses a surfactant composition which is mobile at a temperature in the range of 20-80°C, comprising 20-80% by weight of alkylbenzene sulphonate or alkyl sulphate, 80-20% by weight of ethoxylated non-ionic surfactant and 0-10% by weight of water. The surfactant mixture can be sprayed onto an absorbent particulate solid material, e.g. spray-dried polymer-modified burkeite, so that you get free-flowing washing powder that contains up to approx. 25% by weight surfactant.

EP 43 6 24OA discloses a similar mobile surfactant composition which additionally contains a fatty acid soap. When atomized onto an absorbent solid, this mixture provides powders that have improved flow and dispensing properties.

GB 1 462 134 discloses linear or predominantly linear ethoxylated primary alcohols with closely defined chain length, chain length distribution, ethylene oxide content, ethoxylation distribution and free alcohol content. These materials provide improved oil dirt washing performance compared to conventional commercially available materials.

EP 133 715A discloses an alkylation product mixture which has a particularly high peaked distribution of alkylating substances, in which a single predominant alkylating substance constitutes 20-40% by weight and the amounts of substances which vary significantly from the predominant substance are strictly limited.

EP 384 070A discloses the use as detergency builder of zeolite P having a silicon:aluminum ratio not greater than 1.33 (zeolite MAP). This zeolite has proven to be a more effective and fast binder for calcium ions than conventional zeolite 4A.

GP 544 365A from which the present application claims priority, claims protection for a method of preparing a granular detergent composition having a bulk density of at least 650 g/l, which comprises treating a particulate starting material in a high speed mixer/condenser in the presence of a liquid surfactant mixture comprising an alkyl sulfate (20-80% by weight), an ethoxylated nonionic surfactant (80-20% by weight) and water (0-20% by weight).

The present invention provides a particulate detergent mixture with a bulk density of at least 650 g/l, preferably at least 700 g/l and advantageously at least 800 g/l, which comprises: (a) 15-50% by weight of a surfactant system consisting essentially of : (i) ethoxylated nonionic surfactant which is a primary Cg-Clg alcohol with an average degree of ethoxylation not exceeding 6.5 (from 60 to 100% by weight of the surfactant system) and (ii) primary Cg-C^ -alkyl sulfate (from 0 to 40% by weight of the surfactant system);

(b) 25-48% by weight zeolite,

(c) optionally other detergent ingredients up to 100% by weight, and the mixture is prepared by granulating the zeolite and the surfactant in a high-speed mixer/granulator.

The particulate detergent mixture according to the invention is characterized by a particularly high level of high-performance organic surfactant system. At least 15% by weight of the mixture is made up of the surfactant, and as much as 50% by weight may be present. The mixtures can advantageously contain at least 20% by weight, more advantageously at least 25% by weight, of the surface-active system.

The surface-active system essentially consists of ethoxylated alcohol which has a relatively low degree of ethoxylation, possibly together with a smaller proportion (which does not exceed 40% by weight of the surface-active system) of primary alkyl sulphate.

The proportion of primary alkyl sulphate preferably does not exceed 35% by weight (of the surface-active system) and more preferably does not exceed 30% by weight of the surface-active system. Preferred proportions of alkyl sulfate in the surfactant system are from 0.1 to 35% by weight, more preferably from 5 to 35% by weight and advantageously from 10 to 30% by weight.

Also preferred are surface-active systems where the proportion of alkyl sulphate does not exceed 15% by weight, e.g. 0.1-15% by weight, preferably 0.1-10% by weight.

The ethoxylated alcohol non-ionic surfactant

The ethoxylated alcohol-nonionic surfactant used in the detergent mixtures according to the present invention has a relatively low degree of ethoxylation, which does not exceed 6.5.

When primary alkyl sulfate is absent, the average degree of ethoxylation of the nonionic surfactant is preferably at least 4, but may be lower, e.g. 3-4, when primary alkyl sulfate is present. Accordingly, when primary alkyl sulfate is present, the ethoxylated alcohol preferably has an average degree of ethoxylation in the range of 3 to 6.5.

Whether alkyl sulfate is present or not, the preferred range for the average degree of ethoxylation of the nonionic surfactant is within the range of 4 to 6.5, more preferably 4-6 and most preferably 4-5.5.

A mixture of differently ethoxylated materials can be used, provided that the total degree of ethoxylation meets the specified requirements.

The HLB value of the nonionic surfactant preferably does not exceed 11.0 and preferably does not exceed 10.5. The HLB value is desirable within the range 9.5-10.5.

The chain length of the ethoxylated alcohol will generally vary from C.sub.1 to C.sub.1, preferably from C.sub.0 to C.sub.1; an average one

o lo lb

chain length of C12_15 is preferred. Particularly preferred is ethoxylated alcohol which consists entirely or predominantly of C -C material.

The ethoxylated alcohol is preferably completely or predominantly straight chain. Suitable alcohols are vegetable-derived, e.g. from coconut, which is the most preferred material. Among the synthetic alcohols, Ziegler alcohols are preferred over oxo-based alcohols.

According to a preferred embodiment of the invention, which provides exceptionally good cleaning power for oil stains, the ethoxylated alcohol (which is of course always a mixture of substances having different numbers of ethylene oxide units) is a "narrow range" material having a distribution of ethoxylated substances which is more strongly peaked around a single predominant value than is the case in conventional commercial nonionic surfactants. The content of unethoxylated material is also generally lower and can be further reduced by so-called "stripping".

"Narrow range" alkoxylates are described and claimed to be protected e.g. in EP 133 715A which is discussed earlier.

These are particularly highly peaked mixtures having an average alkylation number of at least 4, in which at least one alkylating substance (the "predominant substance") accounts for approx. 20-40% by weight of the mixture; the proportion of substances that have 3 or more alkylation units above the average is less than 12% by weight; and the substances having 1 more and 1 less alkylation unit than the average are each present in a weight ratio to the predominant substances of 0.6:1 to 1:1. Preferred product mixtures contain 80-95% by weight of alkylating substances having alkylation numbers within ± 2 of the average.

However, the term "narrow area" as used in the present description also covers materials which are not so highly peaked that they satisfy the requirements of the above-mentioned European publication, but which are nevertheless significantly more peaked than e.g. the commercially available ethoxylated alcohols from ICI under the trademark "Synperonic".

The term is therefore defined here to cover any ethoxylated alcohol product in which a single ethoxylating substance constitutes 13% by weight or more, preferably 15% by weight or more, of the product. Conventional ethoxylates contain no more than approx. 10% by weight of any ethoxylating substance. The predominant substance preferably contains 4 or 5 ethoxylation units.

Preferred "narrow range" ethoxylated alcohol used in the compositions according to the invention can have each one or more of the following characteristics: at least 20% by weight of the ethoxylated alcohol can be made up of a single ethoxylating substance;

at least one ethoxylation substance (hereinafter the predominant substance) can constitute from 20 to 40% by weight of the ethoxylated alcohol, the proportion of substance having 3 or more ethoxylation units above the average being less than 12% by weight, and the substance having a more or a smaller one

ethoxylation unit than the average, each being present in a weight ratio to the predominant substance of 0.6:1 to 1:1;

from 80 to 95% by weight of the ethoxylated alcohol can be made up of ethoxylation substances which have an ethoxylation number within ± 2 of the overall average.

Differently defined "narrow range" ethoxylates are also described in GB 1 462 132: these are materials having an average degree of ethoxylation between 3.5 and 6.5, the amount of material having a degree of ethoxylation within the range 2-7EO being least 63% by weight, and the amount of free alcohol does not exceed 5% by weight. These materials are also suitable for use in the mixtures according to the present invention.

The following table shows the ethoxylation distribution of some commercially available coconut-based ethoxylates, both narrow range (NRE7, NRE5 etc), and wide range (E7, E3), the numbers indicating the nominal average degree of ethoxylation in each case.

It is within the scope of the present invention to achieve the preferred value of 4-6.5 for the average degree of ethoxylation by using a mixture of commercial materials, e.g. a (nominal) 3EO ethoxylate and a (nominal) 7E0 ethoxylate in appropriate amounts.

However, it is particularly preferred to use a single commercial material, and the materials designated NRE5, NRE4.6 and NRE4.2 are particularly preferred, NRE4.2 being particularly favoured.

It is particularly preferred, in accordance with the invention, to use completely or predominantly straight-chain ethoxylated alcohol which also has a "narrow range".

It may also be desirable to use a "narrow range" ethoxylate which has a narrower distribution of chain length than the conventional commercial nonionic surfactants have. E.g. are the non-ionic surfactants described in the aforementioned GB 1 462 134 so that at least 65% by weight of the material has a chain length within + 1 carbon atom of the average value.

"Narrow range" ethoxylates are now commercially available in Europe and North America, e.g. from Vista, Union Carbide and Hoechst.

The primary alkyl sulfate

The primary alcohol sulphate (PAS) which may possibly be present, which constitutes up to 40% by weight of the surfactant system, must have a chain length in the range CQ-C.0, preferably C-_-C. cl with

o lo lz lb

a mean value which is preferably in the <C>12_15 range. Particularly preferred is PAS consisting entirely or predominantly of <C>12~<C>14 material.

If desired, mixtures of different chain lengths can be used, as described and claimed protected in EP. 342 917A.

As with the ethoxylated alcohol, predominantly or completely straight chain material is preferred. PAS of vegetable origin, and more particularly PAS from coconut oil (coconut PAS) are particularly preferred. However, it is also within the scope of the invention to use branched PAS as described and claimed protected in EP 439 316A.

PAS is present in the form of the sodium or potassium salt, the sodium salt being generally preferred.

Zeolite - the detergency builder

The amount of zeolite builder in the mixtures according to the invention varies from 25 to 48% by weight.

Depending on the amount and composition of the surfactant system, the zeolite may be the commercially available zeolite 4A which is now widely used in laundry detergents. E.g. can the use of zeolite 4A provide powders that have satisfactory flow properties when 17 wt% surfactant consisting of 30 wt% PAS and 70 wt% nonionic surfactant is present.

However, as the total amount of surfactant and/or the proportion of nonionic surfactant is increased, it is more difficult to achieve acceptable powder flow properties. According to a preferred embodiment of the invention, the zeolite builder which is incorporated in the mixtures according to the invention is zeolite MAP as described and claimed to be protected in EP 384 070A. Zeolite MAP is defined as an alkali metal aluminosilicate of the type zeolite.P which is a silicon: aluminum ratio not exceeding 1.33, preferably in the range 0.90-1.33, and more preferably in the range from 0.90 to 1.20.

Particularly preferred is zeolite MAP having a silicon:aluminum ratio not exceeding 1.07. The calcium binding capacity of zeolite MAP is generally at least 150 mg CaO per g anhydrous material.

In the present invention, the use of zeolite MAP has another advantage that is completely independent of its greater construction efficiency: it enables higher total surfactant levels and more non-ionic surfactant systems, to be used without loss of powder flow properties.

Preferred zeolite MAP for use in the present invention is particularly finely divided and has a d5Q value (as defined below) in the range from 0.1 to 5.0 µm, more preferably from 0.4 to 2.0 µm and most preferably from 0 .4 to 1.0/zm. The amount "d50" indicates that 50% by weight of the particles have a diameter smaller than said number, and there are corresponding amounts of "dg^", "d^^" etc. Particularly preferred materials have a d^ below 3µm as well as a d5Qunder 1 ptm.

Sodium carbonate

The mixtures according to the invention may contain sodium carbonate, to increase the washing ability and to make processing easier. Sodium carbonate may generally be present in amounts ranging from 1 to 60% by weight, preferably 2-40% by weight and most suitably from 2 to 13% by weight.

The optional powder structuring agent

Powder flow can be improved by incorporating a small amount of a powder structuring agent, e.g. a fatty acid (or fatty acid soap), a sugar, an acrylate or acrylate/maleate polymer, or sodium silicate.

The preferred powder structuring agent is fatty acid soap, suitably present in an amount of 1-5% by weight. As will be discussed below in connection with the processing, this is preferably incorporated as the free acid and neutralized in situ.

Powder flow characteristics.

The mixtures according to the invention are characterized by excellent flow properties, despite the high content of mobile high-performance organic surfactant.

For the purposes of the present invention, powder flow is defined on the basis of the dynamic flow rate, in ml/s, measured using the following method. The apparatus used consists of a cylindrical glass tube with an internal diameter of 35 mm and a length of 600 mm. The tube is securely fixed in a position so that its longitudinal axis is vertical. Its lower end is finished with a smooth cone of polyvinyl chloride having an internal angle of 15° and a lower discharge opening with a diameter of 225 mm. A first beam sensor is placed 150 mm above the outlet, and a second beam sensor is placed 250 mm above the first sensor.

To determine the dynamic flow rate of a powder sample, the outlet opening is temporarily closed, e.g. by covering it with a piece of cardboard, and powder is poured through a funnel into the top of the cylinder until the powder level is approx. 10 cm higher than the upper sensor; a spacer between the funnel and the pipe ensures that the filling is even. The outlet is then opened, and the time t (in seconds) it takes for the powder level to fall from the upper sensor to the lower sensor is measured electronically. The measurement is normally repeated two or three times, and an average value is taken. If V is the volume (ml) of the tube between the upper and lower sensors, the dynamic flow rate DFR (ml/s) is given by the following equation:

DFR = V ml/s

t

The averaging and calculation is carried out electronically and a direct reading of the DFR value obtained.

Mixtures and components according to the present invention generally have dynamic flow rates of at least 90 ml/s, preferably at least 100 ml/s.

Other optional ingredients

Fully formulated laundry detergent mixtures in accordance with the present invention may additionally contain any suitable ingredients that are normally encountered, e.g. inorganic salts, e.g. sodium silicate or sodium sulfate; organic salts, e.g. sodium citrate; antigen redeposition aids, e.g. cellulose derivatives and acrylate or acrylate/maleate polymers; fluorescent agents; bleaching agents, bleach precursors and bleach stabilizers; proteolytic and lipolytic enzymes; dyes; colored spots; perfume; foam control agents; fabric softener compounds.

Preparation of the detergent mixtures

The mixtures according to the invention are prepared by granulating the zeolite and the surfactants in a high-speed mixer/granulator, as stated in claim 12. If the surfactant system includes PAS, then this can be incorporated either in salt form (generally as an aqueous paste) or as the free acid (for neutralization in situ).

A particularly preferred method includes the following steps: (i) preparing the surfactant system in the form of a homogeneous, mobile, liquid mixture, and (ii) agglomerating the mobile, liquid surfactant mixture with the zeolite and other solids present in a high-speed mixer/granulator.

If no PAS is to be present, then the surfactant system is simply an ethoxylated alcohol (mixture) which will already take the form of a homogeneous, mobile, liquid mixture.

If PAS is to be present, the homogeneous mobile liquid mixture can be prepared by mixing PAS paste with the nonionic surfactant. Alternatively, the non-ionic material can be mixed during the neutralization of PAS acid with alkali, e.g. in a loop reactor, as described and claimed protected in EP 507 402A.

The high-speed mixer/granulator, also known as a high-speed mixer/condenser, can be a batch machine, e.g. Fukae<®>FS, or a continuous machine, e.g. Lodige<®>Recycler CB3 0.

The procedure is described in more detail, and claimed to be protected, in GP 544 3 65A from which the present application claims priority.

The process allows the incorporation of high levels of surfactant without loss of powder flow properties, particularly when the zeolite component of the mixture is zeolite MAP and/or when soap is present as a structuring agent.

If soap is to be included as a structuring agent, then this is preferably incorporated into the mobile surfactant mixture, either as such or as the corresponding fatty acid (together with an appropriate amount of alkali) for neutralization in situ.

The other optional ingredients mentioned above may be incorporated at any suitable stage in the process. In accordance with normal washing powder manufacturing practice, bleaching ingredients (bleaching agents, bleach precursors and bleach stabilizers), proteolytic and lipolytic enzymes, colored stains, perfume and suds-controlling granules are most suitably mixed (post-dosed) into the dense granular product after it has left the high-speed mixer/ the granulator.

Naturally, the mixtures according to the invention can also be prepared by other methods, which involve spray-drying or non-tower technology or combinations of these two.

The invention shall be further illustrated by the following examples, where parts and percentages are by weight unless otherwise stated.

Examples

The abbreviations used in the examples indicate the following materials: Coconut PAS Linear C12_14-primary alcohol sulphate (sodium salt) derived from coconut oil,

from Philippine Refining Co.

E7(s) C. -._ oxoalcohol 7E0, not "narrow

1j-±3 -

area": Synperonic<®>A7 from ICI

E3(s) C13_15-oxoalcohol 3E0, not "narrow

area": Synperonic<®>A3 from ICI

E7 Coconut alcohol 7E0, not "narrow

area"

E3 Coconut alcohol 3E0, not "narrow

area"

NRE7(s)<C>12_14~<Z>iegler linear "narrow range" alcohol 7E0; Alfonic<®>7, from Vista

NRE3(s)<C>12_14<-Z>iegler linear "narrow range" alcohol 3E0; Alfonic® 3 from Vista

NRE7 Coconut alcohol 7E0, "narrow range"

NRE5 Coconut alcohol 5E0, "narrow range"

NRE4.6 Coconut alcohol 4.6EO, "narrow range"

NRE4.2 Coconut alcohol 4.2E0, "narrow range"

NRE3 Coconut alcohol 3E0, "narrow range"

Zeolite 4A Wessalith<®>P powder from Degussa

Zeolite MAP Zeolite MAP prepared by a method similar to that described in ex. 1-3 of EP 384 070A;

Si:Al ratio 1.07.

Polymer Acrylic/maleic acid copolymer:

Sokalan<®>CP5 from BASF

LAS Linear alkylbenzene sulfonate, sodium salt Perborate mono Sodium perborate monohydrate

TAED Tetraacetylethylenediamine as 83% by weight

granules

EDTMP Ethylenediaminetetramethylenephosphonic acid,

calcium salt: Dequest<®>2041 or 2047

from Monsanto (34% by weight active)

Antifoam Antifoam granules according to EP 266 863B

The terms "carbonate", "silicate" and "metaborate" used in the examples refer to the sodium salts.

Examples 1 to 10 - Washability

Examples 1-4

Detergent mixtures with the following composition were produced:

The surfactant systems were prepared as follows (wt%):

Both mixtures of 30 parts 7EO nonionic surfactant and 40 parts 3EO nonionic surfactant had an average EO number of 4.7 and an HLB value of 10.1.

The percentage of the predominant degree of ethoxylation (4EO) in the NRE mixture was estimated at 14% by weight.

The detergency (removal of radiolabeled triolein soil from polyester) was compared in the tergotometer using a product concentration of 5 g/l, in water of 24° (French) hardness and a wash temperature of 23°C. The results were as follows:

Comparison between the results for comparison ex. A, e.g. 1 and ex. 3 shows how increasing the proportion of non-ionic surfactant at the expense of PAS increases washability: while comparing the results for Examples 1 and 2, and for Examples 3 and 4, shows the washability benefit achieved by changing to "narrow range"- ethoxylated alcohol. The outstandingly good result for e.g. 4 shows the benefits of combining these two measures.

Examples 5-7

A further detergency comparison was carried out, with test fabric carrying a number of different soils. This test was carried out in a Miele<®> computer controlled washing machine, using a product concentration of 5 g/l and with a 30 minute wash at 20°C in water with 26° (French) hardness.

The mixtures had the following general composition:

The surfactant systems were prepared in the following way (wt%):

The results (expressed as reflectance changes at 460 nm) were as follows: Test material 1: kaolin and wool grease on polyester/cotton (WFK 10C) Test material 2: kaolin and wool grease on polyester (WFK 30C) Test material 3: kaolin and sebum on cotton (WFK 10D ) Test substance 4: kaolin and sebum on polyester (WFK 3OD)

Example 8

Using the same tergotometer method as in ex.1-4, the detergency of different surfactant mixtures containing different ethoxylated coconut alcohols were compared.

In each case, the mixtures were as indicated in Ex. 1, and the surfactant systems consisted of 30% by weight coconut PAS and 70% by weight ethoxylated alcohol. The ethoxylated alcohol component was made (i) by mixing E7 and E3 (broad range) in varying proportions, or (ii) by mixing NRE7 and NRE3 (narrow range) in varying proportions, or

(iii) using a single narrow-range ethoxylate.

The actual degrees of ethoxylation will appear from the table given earlier in this description.

Detergency (% removal of radiolabeled triolein from polyester) as a function of the degree of ethoxylation and starting ethoxylated alcohol is shown in the following table.

These results illustrate the advantage of average-

equal degrees of ethoxylation of 6 or less; the improvements achieved by moving towards narrow-range ethoxylates; and the special advantages of using a single, narrow-area material, especially NRE4.2.

Example 9

The procedure from e.g. 8 was repeated using a series of mixtures that had a more nonionic-rich surfactant system: 10 wt% cocoPas and 90 wt% ethoxylated alcohol. The results are shown in the following table.

Again, the advantages of using narrow-range ethoxylates, especially certain materials, are obvious.

Example 10

The procedure from e.g. 8 and 9 were repeated using a series of compositions in which the surfactant system consisted entirely of ethoxylated nonionic surfactant.

The results are shown in the following table.

These results show a similar pattern to those shown by the results in ex. 8 and 9, and they also clearly illustrate the significant drop in detergency at average degrees of ethoxylation below 4 when no PAS is present.

Examples 11 to 32 - Powder properties

Examples 11 and 12, Comparative example A

High bulk density base washing powders, consisting of the surfactant system, zeolite and (in some cases) sodium carbonate, were prepared by agglomeration in a Fukae<®>FS100 high speed batch mixer/granulator. These powders are intended as completely composed detergent mixtures, but can easily be transferred to such mixtures by mixing in (post-dosing) other components, e.g. bleaching ingredients, enzymes, foam-regulating granules and perfume.

The surfactant system was as follows:

3 0 wt% coconut PAS

3 0 wt% E7(s)

40 wt% E3(s)

The mixtures, in parts by weight and percentages, are shown below.

A homogeneous liquid mixture of the surfactants was made by neutralizing PAS acid with sodium hydroxide solution in a loop reactor in the presence of the nonionic surfactants. Zeolite and (where present) sodium carbonate were metered into the Fukae mixer, the liquid surfactant mixture was added and the mixture granulated. The granular product was then dried using a fluidized bed.

For Comparative Example A, it proved impossible to obtain a granular product; the mixture formed a solid mass. Addition of 10 parts of sodium carbonate (ex. 11) enabled the preparation of a granular product. With zeolite MAP (Ex. 12), at a somewhat lower level, the same amount (in parts - actually slightly higher percent loading) of the surfactant system could be incorporated without the need for sodium carbonate, and a free-flowing granular product was obtained.

Comparative examples B to E

Further attempts to produce base powder containing zeolite 4A with varying amounts of surfactant (the same system as in ex. A, 11 and 12) and carbonate were not successful:

Composition in parts by weight

Composition in percentages

Mix B produced a solid mass, while Mixes C, D and E initially produced free-flowing powders which, however, lost their flow on drying.

Examples 12 to 15

An experiment similar to that in comparative examples B to E, but where zeolite MAP was used, gave powders with good flow properties, even with a significantly higher content of surfactant. The composition and powder properties of the mixtures are shown below.

Examples 16 and 17

Mixtures similar to those in Comparative Examples B to E were made, but this time fatty acid soap was present.

The preparation method for these powders was slightly different from that used in previous examples. A homogeneous, mobile mixture was made by mixing PAS in sodium salt form (70% by weight), fatty acid, sufficient sodium hydroxide solution to neutralize the fatty acid, and the nonionic surfactants. Ingredients were dosed into the Fukae mixer in the order of zeolite, carbonate, surfactant mixture, granulation/densification was carried out as in the previous examples, and the products were finally dried using a fluidized bed.

Powders with excellent flow properties were obtained.

Mixtures

Powder properties

These examples, when compared with comparative examples C to F, show that the incorporation of fatty acid soap made it possible to produce good powders with a high density of mixtures which cannot be processed in its absence.

Examples 18 and 19

Mixtures similar to those from e.g. 16 and 17 were made by the same method, but using zeolite MAP instead of zeolite 4A.

Mixtures

Powder properties

Comparison between these examples and examples 12 to 15 shows that the incorporation of soap improved flow, but when zeolite MAP was used, it was not essential in order to obtain acceptable powders.

Examples 20 and 21, Comparative Examples F and G

Basic washing powders in general as described in ex. 11, 12 and A were prepared using a different surfactant system:

10 wt% coconut PAS

40% by weight E7(s)

50 wt% E3(s)

The surfactant system was prepared as a homogeneous, mobile mixture by the method described in ex. 11, 12 and A, and the other process steps were also carried out as in the examples.

Composition in parts by weight

Composition in percent

In the case of comparative examples F and G, it proved impossible to obtain a granular product; both mixtures formed a solid mass. Addition of 25 parts of sodium carbonate to the mixture based on zeolite 4A (Ex. 20) was necessary to enable preparation of a granular product. With zeolite MAP (Ex. 21) only 15 parts of sodium carbonate were required.

Examples 22 and 23, comparative example H

Mixtures similar to those in ex. 18 and 19 were made, but they contained higher levels of zeolite.

Composition in parts by weight

Composition in percent

Mixture H would not give a granular product: 10 parts of sodium carbonate were required to produce a workable mixture. However, with zeolite MAP at this level, no carbonate was required despite the high percentage level of surfactant in this mixture (Ex. 23).

Example 24, Comparative Examples J and K

Mixtures based on zeolite 4A, with and without soap, were made using the surface-active system in ex. 20-22. The fatty acid soap was incorporated by mixing fatty acid and an equivalent amount of sodium hydroxide solution into the surfactant mixture (prepared as described in Ex. 11) prior to adding the mixture to the Fukae mixer. Composition in percent

Mixture J gave a non-flowing product both before and after drying, while Mixture K initially gave a good product but lost its flow upon drying. A larger amount of soap (Ex. 24) gave an excellent powder with a bulk density of 920 g/l and a dynamic flow rate of 109 ml/s.

Examples 25 and 2 6

Mixtures similar to those in ex. 24 and J, but containing zeolite MAP and a higher level of surfactant were made.

Mixtures

Powder properties

Example 27, comparative example L

Mixtures similar to those in ex. J and K were made using a different kind of surfactant system:

40% by weight E7(s)

60 wt% E3(s)

Mixtures

Mixture L initially gave a good product, but lost its flow on drying. Incorporation of soap (Ex. 27) gave an excellent powder with a bulk density of 801 g/l and a dynamic flow rate of 139 ml/s.

Examples 28 and 2 9

Examples L and 27 were repeated using zeolite MAP instead of zeolite 4A.

Mixtures

Powders

With this mixture, the incorporation of soap was not necessary to achieve good powder properties; on the contrary, no benefit was observed.

Example 3 0

A mixture similar to that in ex. 24, but containing a different kind of nonionic surfactant, NRE5, was made. All solid components had a particle size lower than 200 µm.

The method of manufacture was essentially as described in ex.

11. The average residence time of the granular detergent mixture in the high speed batch mixer/granulator was approximately 3 min.

The granular detergent mixture that was obtained had a bulk density of approx. 770 g/l and a dynamic flow rate of 101 ml/s.

Example 31

A granular detergent mixture similar to that in ex. 30 was prepared using a continuous high speed mixer/granulator, Lodige<®>Recycler CB30.

The liquid surfactant mix included fatty acid in combination with a stoichiometric amount of sodium hydroxide, which during the mixing and densification process formed soap.

The rotation speed was 1600 rpm, and the average residence time of the granular mixture in the Recycler apparatus was approximately 10 sec.

'The composition of the granular material leaving the Recycler was as follows.

The room density was approx. 700 g/l, • the particle size 500-600 µm, and the powder properties were good.

Examples 32 to 34, Comparative Example M

Fully compounded washing powders were prepared with the compositions given below. Post dosed

Comparative mixture M is a high performance concentrated powder, based on a different surfactant system (LAS with non-ionic surfactants) similar to that used in premium powders currently on sale in Europe.

Surfactant systems (% by weight)

The total amount of (non-soap) surfactant in each mixture was 17% by weight.

All base powders were prepared in the previously discussed Fukae FS100 high-speed batch mixer/granulator.

Mixture M was prepared as follows. Zeolite and carbonate

(including an additional amount for neutralization of LAS acid)

was dosed into the Fukae mixer, followed by LAS acid, then a homogeneous surfactant mixture (non-ionic surfactant), fatty acid and an equivalent amount of sodium hydroxide solution). After granulation, the powder was dried using a fluidized bed, and the remaining ingredients were post-dosed.

Mixtures 32 and 33 were prepared as follows. Homogeneous surfactant mixtures were made by mixing PAS paste (70%), nonionic surfactant, fatty acid and an equivalent amount of sodium hydroxide solution. Zeolite and carbonate were dosed into the Fukae mixer, followed by the surfactant mixture. After granulation, the powders were dried using a fluidized bed, and the remaining ingredients were post-dosed.

Mixture 34 was prepared in the same manner, except that no carbonate was present during granulation.

Powder properties

Washability results

Washability was assessed in a Miele washing machine, in the presence of a soiled load, using a product concentration of 5 g/l, water with 26° (French) hardness and a wash temperature of 30°C. The measure of detergency was the change in reflectance (460 nm) of a polyester test fabric soiled with kaolin and sebum (WFK 30D).

Examples 35 to 37

Additional washing powder formulations containing zeolite MAP and coconut non-ionic surfactants are shown below.

Similar mixtures can be made containing the narrow range coconut non-ionic surfactants NRE7 and NRE3, instead of the wide range materials E7 and E3, in the same proportions; or instead one of the individual materials NRE5, NRE4.6 or NRE4.2.

Claims (14)

1. Particulate detergent mixture with a bulk density of at least 650 g/l, characterized in that it comprises: (a) 15-50% by weight of a surfactant system consisting of: (i) ethoxylated non-ionic surfactant which is a primary CQ-C. 0-alcohol with an average oh lol degree of ethoxylation not exceeding 6.5 (60-100% by weight of the surfactant system), and (ii) primarily C_-C. _-alkyl sulfate (0-40% by weight of the surface o -L o active system); (b) 25-48% by weight zeolite, (c) possibly other detergent ingredients up to 100% by weight, the mixture being prepared by granulating the zeolite and the surfactant in a high-speed mixer/granulator. 2. Particulate detergent mixture as stated in claim 1, characterized in that the surface-active system (a) comprises 0.1-35% by weight of alkyl sulphate (ii). 3. Particulate detergent mixture as set forth in any of the preceding claims, characterized in that the surfactant system includes alkyl sulfate (ii) and the ethoxylated alcohol (i) has an average degree of ethoxylation of 3-6.5. 4. Detergent mixture as specified in claim 1 or 2, characterized in that the surfactant system does not contain any alkyl sulfate (ii) and that the ethoxylated alcohol (i) has an average degree of ethoxylation of 4-6.5. 5. Detergent mixture as stated in any of the preceding claims, characterized in that the ethoxylated alcohol has an average degree of ethoxylation of 4-5.5. 6. Detergent mixture as stated in any of the preceding claims, characterized in that at least 13% by weight of the ethoxylated alcohol is made up of a single ethoxylation substance. 7. Detergent mixture as specified in claim 6, characterized in that the individual ethoxylation substance contains 4 or 5 ethoxylation units per moles of alcohol. 8. Detergent mixture as stated in claim 6 or 7, characterized in that the ethoxylated non-ionic surfactant consists of a single material which has an average degree of ethoxylation in the range 4-5. 9. Detergent mixture as stated in any of the preceding claims, characterized in that it contains at least 17% by weight of the surfactant system. 10. Detergent mixture as set forth in any of the preceding claims, characterized in that the zeolite is zeolite P having a silicon:aluminum ratio not exceeding 1.33. 11. Detergent mixture as stated in any of the preceding claims, characterized in that it comprises 1-5% by weight of fatty acid soap. 12. Method for producing a particulate detergent mixture as stated in claim 1, characterized in that it includes mixing and granulating the zeolite, the ethoxylated alcohol, the primary alkyl sulfate (if present) in acid or salt form, as well as possibly other compatible ingredients, by granulation in a high-speed mixer/granulator. 13. Method as stated in claim 12, characterized by the following steps: (i) to prepare the surface-active system in the form of a homogeneous, liquid mixture, and (ii) to agglomerate the homogeneous, liquid, surface-active mixture with the zeolite and other solids which are present in the high speed mixer/granulator. 14. Method as stated in claim 12 or 13, characterized in that the homogeneous, liquid surfactant mixture also comprises a fatty acid and an alkali or a fatty acid soap.