Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Clay or inorganic aluminosilicate salt component
Reexamination Certificate
2000-06-08
2002-09-24
Gupta, Yogendra N. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Clay or inorganic aluminosilicate salt component
C510S349000, C510S441000, C510S444000, C510S446000, C510S451000, C510S466000, C510S508000, C510S511000, C510S532000
Reexamination Certificate
active
06455490
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a granular detergent component containing zeolite MAP builder, and to particulate laundry detergent compositions containing it. More particularly the invention relates to zeolite-built compositions having bulk densities within the range of from 600 to 900 g/l.
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 via the spray-drying route is therefore not preferred.
The present inventors have now discovered that a non-tower zeolite MAP base powder of lower bulk density may be produced, which may be used to formulate detergent powders of lower final bulk density. If desired, the bulk density may be lowered further by also including in the formulations a lesser amount of a spray-dried component. The resulting products have good powder properties and the stability of sodium percarbonate is not compromised.
PRIOR ART
Zeolite MAP as a new detergency builder is disclosed in EP 385 070B (Unilever). The high liquid carrying capacity of zeolite MAP and its use in the preparation of high performance laundry detergent powders are disclosed in EP 521 635A and EP 544 492A (Unilever). The beneficial effect of zeolite MAP on sodium percarbonate stability is disclosed in EP 522 726B (Unilever).
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 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.
DEFINITION OF THE INVENTION
The present invention provides a non-spray-dried granular component suitable for use in a particulate zero-phosphate laundry detergent composition, the component comprising from 10 to 30 wt % of organic surfactant and from 20 to 50 wt % of zeolite, wherein the zeolite consists wholly of zeolite MAP and the component has a bulk density not exceeding 700 g/l.
The present invention further provides a particulate zero-phosphate laundry detergent composition having a bulk density within the range of from 550 to 950 g/liter, which comprises a granular detergent component as defined in the previous paragraph, in admixture with one or more other detergent ingredients.
DETAILED DESCRIPTION OF THE INVENTION
The Granular Zeolite-MAP-based Detergent Component
The first aspect of the present invention is a non-spray-dried zeolite-MAP-based granular detergent component having a lower bulk density than previously prepared zeolite-MAP-based non-spray-dried detergent components.
Zeolite MAP has been described in EP 384 070B (Unilever). It is zeolite P having a silicon to aluminium ratio (molar) not exceeding 1.33:1, preferably not exceeding 1.06:1, and most preferably about 1:1.
The granular detergent component has a bulk density not exceeding 700 g/l, preferably within the range of from 600 to 700 g/l and more preferably within the range of from 600 to 650 g/l.
The granular component comprises from 10 to 30 wt % of organic surfactant and from 20 to 50 wt % of zeolite, wherein the zeolite consists wholly of zeolite MAP. Preferably it contains from 30 to 50 wt % of zeolite MAP.
The granular component may suitably further comprise:
from 10 to 45 wt % of sodium carbonate plus optional sodium sulphate,
optionally from 0 to 10 wt % of layered sodium silicate,
and optionally minor ingredients to 100 wt %.
Typically the granular component may comprise:
from 10 to 25 wt % of anionic sulphonate or sulphate surfactant,
from 5 to 20 wt % of ethoxylated nonionic surfactant,
from 30
Berthod Daniel Pierre Marie
Joyeux Christophe Michel Bruno
Langeveld Johannes Hendrikus
Gupta Yogendra N.
Mitelman Rimma
Mruk Brian P.
Unilever Home & Personal Care USA Division of Conopco, In.c
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