Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2000-01-26
2001-08-14
Douyon, Lorna M. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S231000, C510S446000
Reexamination Certificate
active
06274538
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a washing detergent in the form of a tablet comprising one or more detergent compositions and whercin at least one detergent composition dissolves in a dishwashing machine in less than three minutes.
BACKGROUND
Detergent compositions in tablet form are known in the art. It is understood that detergent compositions in tablet form hold several advantages over detergent compositions in particulate foni, such as ease of handling, transportation and storage.
Detergent tablets are most commonly prepared by pre-mixing components of a detergent composition and forming the pre-mixed detergent components into a tablet using a tablet press. Tablets are typically formed by compression of the detergent components into a tablet. Tablets must be compressed with sufficient compression pressure such that the handling, transportation and storage benefits described above can be achieved. However, a problem associated with the compression of the detergent components is that the dissolution rate of the tablet decreases as the compression pressure is increased.
The object of the present invention is to provide a detergent tablet comprising compressed detergent components which have a rapid dissolution rate.
In addition, the Applicant has found that components of a detergent composition that improve dissolution of the detergent composition are sometimes unstable, activating dissolution of the tablet before it is required. The present invention, whilst providing tablets that dissolve rapidly also provides a solution to this problem of in stability.
SUMMARY OF INVENTION
In accordance with the present invention there is provided a washing machine detergent in the form of a tablet comprising one or more deterg,ent compositions and wherein at least one detergent composition is compressed and dissolves in a dishwashing machine in less than 3 minutes.
Preferably the detergent composition dissolves in less than 2.5 minutes, most preferably less than 2 minutes or even less than 1 minute, determined according to DIN 44990 using a dishwashing machine available fiom Bosch on the normal 65° C. washing programme with water hardness at 18°d.
In a further embodiment of the present invention there is provided a phosphate-containing detergent in the from of a tablet comprising one or more detergent compositions wherein at least one detergent composition comprises an explosive detergent-release component.
DETAILED DESCRIPTION OF THE INVENTION
For the purposes of the present invention one or more detergent compositions which is compressed and dissolves rapidly in less than 3 minutes. The tablet may be a multi-layer tablet wherein each layer comprises a detergent composition. Optional additional layers may be formed by compression or may be non-compressed layers.
On compression of a detergent composition into a tablet, the components are brought into close proximity with each other. A result of the close proximity is that certain of the components may react with each other, becoming unstable, inactive or exhausted. A solution to this problem, as seen in the prior art, has been to separate detergent components that may potentially react with each other, especially when the components are compressed into tablet form. Separation of the components has been achieved by, for example, preparing multi-layer tablets wherein the components that may potentially react with each other are contained in different layers of the tablet. Multiple-layer tablets, are traditionally prepared using multiple compression steps.
Where the tablet is a multi-layer tablet, at least one layer of compressed detergent composition dissolves in less than three minutes, preferably less than two minutes or even one minute. Such an embodiment may provide performance benefits as it enables rapid deliv cry of selected specific detergent components into the wash solution. In a preferred aspect of the present invention specific detergent components include surfactant, enzymes, source of alkalinity, bleach and builder.
The rapidly dissolving detergent composition (e.g. the detergent composition that dissolves in less than three minutes), preferably comprises an explosive detergent-releasing component. Preferably the slower dissolving layers will also dissolve in a dishwashing machine in less than three minutes, but dissolves slower than the rapidly dissolving layer. Thus, sequential release of detergent components may be effected. Preferred aspects of the invention include those in which: (i) builder is released prior to bleach; (ii) builder is released prior to enzyme; (iii) enzyme is released prior to bleach; (iv) surfactant is released prior to builder.
Dissolution of the detergent composition in less than three minutes may be effected by, for example, incorporation of (i) an explosive detergent-releasing component; (ii) selecting components having particle size range that enhances fast dissolution of the component or mixtures thereof. The term explosive detergent-releasing component includes gas-producing reactants, pre-formed and trapped gas, disintegrating agents and mixtures thereof.
In a detergent tablet according to the invention which comprises an explosive detergent-releasing component, the explosive detergent-releasing component preferably comprises gas-producing reactants. The gas-producing reactants react with one another to form a gas in situ on contact with water in a dishwashing machine. Alternatively, the gas may be pre-formed and trapped in one or more detergent compositions of the tablet, so that as the detergent composition begins to dissolve the gas is released increasing the rate of dissolution of the detergent composition. Examples of suitable gases include carbon dioxide, nitrogen dioxide, oxygen and/or any other non-toxic, non-flammable gas. Thus, the explosive detergent-releasing component when incorporated into a detergent composition which forms all or part of the detergent tablet, results in a rapidly dissolving detergent composition which preferably dissolves in a dishwashing machine in less than three minutes. The explosive detergent-releasing component is present at a level of at least 30%, preferably at least 80% by weight of the detergent composition.
In order to form the gas in situ, the detergent tablet may contain gas-producing reactants such as an acid and an alkali. Suitable acids include mono, di or tri basic acids having pka in the range of 1.0 to 6.9. Preferred acids include amino sulphonic acids, organo phophonic acids such as 1-hydroxy ethane-1,1-diphosphonic acid (HEDP acid), polycarboxylic acids, preferably citric acid, malic acid, maleic acid, malonic acid, itaconic acid, tartaric acid, oxalic acid, glutaric acid, glutamic acid, lactic acid, fumaric acid, glycolic acids and mixtures thereof. Citric acid and/or HEDP acid are particularly preferred acids. Suitable alkalis include alkali metal silicate, carbonate, bicarbonate and sesqui carbonate and mixtures thereof. Metasilicate and/or carbonate, and particularly bicarbonate are preferred. Sodium salts of the above are particularly preferred. Other gas-producing reactants include perborate and/or percarbonate.
The explosive detergent-releasing component may comprise a disintegrating agent. Suitable disintegrating agents include agents that swell on contact with water or dissolve more rapidly than surrounding components thereby facilitating water influx and/or efflux by forming channels in the tablet. Any known disintegrating suitable for use in laundry or dishwashing applications is envisaged for use herein. Suitable disintegrating agent include starch, starch derivatives, alginic acid or salts thereof, carboxymethylcellulose (CMC), CMC-based polymers, polyvinyl pyrrolidone (PVP), cross linked PVP, sodium acetate, potassium carbonate, potassium sulfate, Glaubers salts, sugars, especially mannitol and sorbitol, aluminium oxide and mixtures thereof.
Alternatively rapid dissolution of the detergent composition can be achieved by selecting detergent components having a particular particle size range. In a preferred aspe
Cook C. Brant
Douyon Lorna M.
Miller Steven W.
The Procter & Gamble & Company
William Zerby Kim
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