Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Heterogeneous arrangement
Reexamination Certificate
2001-03-13
2003-06-03
Douyon, Lorna M. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Heterogeneous arrangement
C510S276000, C510S351000, C510S443000, C510S444000, C510S495000, C510S498000, C510S507000, C510S512000
Reexamination Certificate
active
06573231
ABSTRACT:
TECHNICAL FIELD
The present invention relates to particulate laundry detergent compositions. The invention relates more particularly to compositions, especially zeolite-built compositions, having bulk densities within the range of from 550 to 900 g/l.
BACKGROUND
Detergent powders normally consist of a principal homogeneous granular component, normally referred to as the base powder, containing at least organic surfactant and inorganic builder, and generally containing other robust ingredients. Traditionally the base powder has been prepared by spray-drying a slurry at elevated temperature to give porous crisp granules of low bulk density, for example 300 to 500 g/l. Heat sensitive and/or less robust ingredients such as bleaches, enzymes, antifoams and certain nonionic surfactants are then admixed (postdosed) to the base powder. Postdosing generally causes an increase in bulk density but values higher than about 650 g/l are rare.
In recent years “compact” or “concentrated” powders having a higher bulk density than is attainable by spray-drying and postdosing alone have become popular. In such powders, the base powder may be prepared by densifying a spray-dried powder, or by wholly non-tower processing (mechanical mixing). Concentrated base powders typically have a bulk density of at least 700 g/l. Postdosing of additional ingredients, as in traditional powders, can bring the bulk density up to 800 g/l or above.
Concentrated (non-tower) powders have various advantages, for example: their production consumes less energy and produces less pollution than does spray-drying; there is more freedom to incorporate a wide range of ingredients because heat sensitivity is less critical; the powders can be produced to a lower moisture content, so stability of moisture-sensitive ingredients such as sodium percarbonate is better. Spray-dried powders, on the other hand, tend to have better powder properties; they may be dosed into drum-type front-loading washing machines via the dispenser drawer, whereas non-tower powders generally require a dispensing device, and they disperse and dissolve in the wash liquor more quickly and completely. They also attract considerable consumer loyalty, for example, because the dosage amount and method are familiar.
Accordingly, while concentrated powders have become popular and offer many advantages, spray-dried powders have retained a considerable consumer following. There is therefore a need for powders which combine the advantages of both types of powders without the disadvantages. The manufacturer will also wish to be able to offer a portfolio of products ranging from conventional to concentrated, and to do so using as small a number of base powder variants as possible.
On the other hand, having optimised formulation parameters with respect to detergency performance, the manufacturer will not want the overall compositions of the various products to deviate too far from the optimum.
The present inventors have accordingly proposed the use of two base granules of different bulk densities but similar compositional parameters that can be combined in a wide range of ratios, enabling the formulator either to vary bulk density at constant composition, or to vary composition at constant bulk density, in both cases whilst preserving optimum performance parameters and allowing for flexible dosing either via the washing machine dispenser or via a dispensing device.
PRIOR ART
WO 98 54288A (Unilever) discloses a particulate laundry detergent composition having a bulk density of at least 550 g/l, comprising a non-tower base powder containing surfactant and builder, and a spray-dried adjunct containing inorganic salts and optionally containing a minor amount of surfactant, wherein the non-tower base powder constitutes from 35 to 85 wt % of the total composition.
GB 1 371 101 (Unilever) discloses a detergent composition prepared by simultaneously spray-drying two different slurries, one rich in anionic surfactant and containing a lesser amount of, or no, nonionic surfactant, and the other rich in nonionic surfactant and containing a lesser amount of, or no, anionic surfactant.
WO 96 34084A (Procter & Gamble/Dinniwell) discloses a low-dosage, highly dense detergent powder comprising about 40 to 80% by weight of spray-dried detergent granules, about 20 to 60% by weight of dense detergent agglomerates, and about 1 to 20% by weight of postdosed ingredients. Preferably the weight ratio of spray-dried granules to agglomerates is 1:1 to 3:1.
EP 342 043A (Procter & Gamble) discloses detergent powders containing two different surfactant-containing granules, one of which has a defined dissolution rate.
JP 03 084 100A (Lion) discloses a high bulk density detergent powder prepared by mixing spray-dried detergent particles, containing 20 to 50% by weight of anionic surfactant and 10 to 70% by weight of zeolite, with 1 to 15% by weight of separately prepared high bulk density detergent granules.
DEFINITION OF THE INVENTION
The present invention provides a particulate laundry detergent composition having a bulk density within the range of from 550 to 900 g/l, comprising non-soap organic surfactants and detergency builders, the composition comprising at least two different granular multiingredient components:
(i) a first granular component comprising non-soap surfactant and detergency builder and having a bulk density within the range of from 550 to 1000 g/l, preferably from 600 to 1000 g/l, the first granular component having a weight ratio of a first ingredient type to a second ingredient type of r,
(ii) a second granular component comprising non-soap surfactant detergency builder and having a bulk density within the range of from 300 to 550 g/l and having a weight ratio of the first ingredient type to the second ingredient type of r′,
wherein the ratio of r to r′ is within the range of from 1.25:1 to 1:1.25.
DETAILED DESCRIPTION OF THE INVENTION
The detergent compositions are composed of at least two different multiingredient components, hereinafter referred to as base granules, each of which contains both organic non-soap surfactant and inorganic detergency builder and each of which may contain other detergent ingredients. The final composition also may, and preferably does, contain other admixed particulate or granular ingredients.
The first base granule has a bulk density of from 550 to 1000 g/l, preferably from 600 to 1000 g/l and more preferably from 700 to 950 g/l, and is preferably a mechanically mixed granule, ie is prepared by a wholly non-tower (non-spray-drying) process. Alternatively, and less preferably, it may be prepared by spray-drying and post-densification.
The second base granule has a bulk density of from 300 to 550 g/l, preferably from 350 to 500 g/l, more preferably from 400 to 500 g/l, and is preferably a spray-dried granule.
According to the invention, the two base granules are used together preferably in a weight ratio of from 0.1:1 to 5:1, more preferably from 0.1:1 to 3:1, most preferably from 0.1:1 to 2:1. As indicated above, further particulate or granular ingredients unsuitable for incorporation in a base granule, for example, bleaches, enzymes and perfume, may be subsequently admixed (postdosed), to give a final composition having a bulk density within the range of from 550 to 900 g/l, preferably from 600 to 900 g/l and more preferably from 600 to 800 g/l.
The two base granules are related compositionally to one another in that the ratios of a first ingredient type to a second ingredient type in the two base granules are similar, or, most preferably, almost the same. Accordingly, whatever the mixing ratio of the two base granules, the ratio of the first ingredient type to the second ingredient type in the resulting mixture will vary very little, and can conform to the detergency performance optimum identified by the manufacturer. The same principle may apply to other ingredient types present in both base granules, so that, for example, the ratios of the second ingredient type to a third ingredient type, or of a third ingredient type to a four
Bakker Vera Johanna
Berthod Daniel Pierre
Joyeux Christophe Michel
Wright Duncan Howard
Douyon Lorna M.
Mitelman Rimma
Unilever Home & Personal Care division of Conopco, Inc.
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