Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Clay or inorganic aluminosilicate salt component
Reexamination Certificate
2000-06-08
2002-05-21
Kopec, Mark (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Clay or inorganic aluminosilicate salt component
C510S349000, C510S441000, C510S443000, C510S446000, C510S452000, C510S466000, C510S508000, C510S511000, C510S531000
Reexamination Certificate
active
06391846
ABSTRACT:
TECHNICAL FIELD
The present invention relates to particulate laundry detergent compositions containing zeolite builder. More particularly the invention relates to zeolite-built compositions having bulk densities within the range of from 600 to 900 g/l.
1. Background
Particulate laundry detergent compositions of reduced or zero phosphate content containing zeolite builder are now well known and widely available. The original detergent zeolite was zeolite A, available in slurry, granule and powder forms, which has been used in low- and zero-phosphate laundry powders for many years. More recently, zeolite MAP (maximum aluminium zeolite P), as described and claimed in EP 384 070B (Unilever), has also become available.
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 400 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 550 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 selection of products ranging from conventional to concentrated. From the manufacturer's point of view, it is operationally advantageous if this can be done using a single common base powder, or at least as small a number of base powder variants as possible.
As described and claimed in EP 521 726A and EP 544 492B (Unilever), zeolite MAP has a better carrying capacity for mobile organic ingredients such as hydrophobic ethoxylated nonionic surfactants, which makes it significantly more suitable than zeolite A for formulating concentrated high-performance non-tower base powders, allowing higher surfactant loadings without loss of powder properties such as flow. Another advantage of zeolite MAP, as described and claimed in EP 522 726B (Unilever), is that, unlike zeolite A, it does not destabilise sodium percarbonate bleach, and allows the formulation of concentrated powders containing percarbonate. Zeolite MAP, therefore, is ideally suited for use in non-tower base powders of high quality.
However, zeolite MAP is not ideal for preparing spray-dried powders, tending to give dusty powders containing high levels of fine particles. It is also available only as a dried powder, so its use in a slurry-based process is uneconomic and wasteful of energy. The use of zeolite MAP to prepare powders of lower bulk density is therefore not preferred.
The present inventors have now discovered that it is possible for formulate powders of lower bulk densities based on a non-tower zeolite MAP base powder, if there is also included in the formulations a spray-dried zeolite A base powder, preferably in a minor amount. The resulting products have good powder properties and, surprisingly, the stability of sodium percarbonate is not compromised.
2. 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 and a spray-dried adjunct, wherein the non-tower base powder constitutes from 35 to 85 wt % of the total composition. The non-tower base powder may contain zeolite MAP. The spray-dried adjunct preferably comprises crystal-growth-modified sodium sesquicarbonate.
WO 98 54281A, WO 98 54286A and WO 98 54287A (Unilever) disclose a granular detergent component (adjunct) containing a high level of anionic surfactant, prepared by a flash-drying process. The adjunct contains 70 wt % linear alkylbenzene sulphonate, 20 wt % zeolite A, and 5 wt % of zeolite MAP. 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.
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 accordingly provides a particulate zero-phosphate laundry detergent composition containing zeolite MAP and zeolite A in a weight ratio of at least 1:1.
More particularly, the present invention provides a particulate zero-phosphate laundry detergent composition having a bulk density within the range of from 600 to 900 g/l, preferably from 650 to 800 g/l and most preferably from 650 to 750 g/l, containing zeolite MAP and zeolite A in a weight ratio of at least 1:1.
According to a preferred embodiment of the invention, the composition comprises at least two different granular components containing organic surfactant and zeolite builder, wherein a first granular component contains zeolite MAP and a second granular component contains zeolite A.
DETAILED DESCRIPTION OF THE INVENTION
The particulate laundry detergent composition of the invention contains zeolite MAP as the principal builder and also contains zeolite A, in a lesser amount.
The composition of the invention has a bulk density of from 600 to 900 g/l, preferably from 600 to 800 g/l and more preferably from 650 to 750 g/l.
The range of 650 to 750 g/l is lower than the range typical for concentrated powders but higher than that typical of powders prepared by spray-drying and postdosing only. Especially preferred compositions have a bulk density within the range of from 700 to 750 g/l. However, compositions according to the invention containing high levels of postdosed inorganic salts may have higher bulk densities.
A preferred composition of the invention comprises:
(i) a first granular component containing organic surfactant and zeolite MAP which is non-spray-dried and has a bulk density of from 550 to 950 g/l, preferably from 600 to 800 g/l;
ii) a second granular component containing organic surfactant and zeolite A which is spray-dried and has a bulk density of less than 500 g/l, preferably
Berthod Daniel Pierre Marie
Joyeux Christophe Michel Bruno
Langeveld Johannes Hendrikus
Kopec Mark
Mitelman Rimma
Mruk Brian P.
Unilever Home & Personal Care USA. division of Conopco, Inc.
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