Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Solid – shaped macroscopic article or structure
Reexamination Certificate
2000-02-02
2002-09-17
Douyon, Lorna M. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Solid, shaped macroscopic article or structure
C510S224000, C510S294000, C510S298000
Reexamination Certificate
active
06451754
ABSTRACT:
TECHNICAL FIELD
The present invention provides a detergent tablet comprising a compressed portion and a non-compressed, non-encapsulating portion.
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 form, 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 components of the detergent composition into a tablet. However, the Applicant has found that some components of a detergent composition are adversely affected by the compression pressure used to form the tablets. These components could not previously be included in a detergent tablet composition without sustaining a loss in performance. In some cases the components may even have become unstable or inactive as a result of the compression.
Furthermore as the components of the detergent composition are compressed, the components are brought into close proximity with each other. A result of the close proximity of the components can be that certain of the components react with each other, becoming unstable, inactive or exhausted. A solution to this problem, as seen in the prior art, has been to separate components of the detergent composition that may potentially react with each other when the detergent composition is compressed into tablet form. Separation of the components has been achieved by, for example, preparing multiple-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. Layers of the tablet that are subjected to more than one compression step are subjected to a cumulative and potentially greater overall compression pressure. An increase in compression pressure of the tabletting press is known to decrease the rate of dissolution of the tablet with the effect that such multiple layer may not dissolve satisfactorily in use.
Other methods of achieving separation of detergent components have been described. For example EP-A 0,224,135 describes a dishwashing detergent in a form which comprises a warm water-soluble melt, into which is pressed a cold water-soluble tablet. The document teaches a detergent composition that consists of two parts, the first part dissolving in the pre-rinse and the second part dissolving in the main wash of the dishwasher.
EP-B-0,055,100 describes a lavatory block formed by combining a slow dissolving shaped body with a tablet. The lavatory block is designed to be placed in the cistern of a lavatory and dissolves over a period of days, preferably weeks. As a means of controlling the dissolution of the lavatory block, the document teaches admixing one or more solubility control agents. Examples of such solubility control agents are paradichlorobenzene, waxes, long chain fatty acids and alcohols and esters thereof and fatty alkylamides. Detergent tablets for use in laundry or automatic dishwashing must substantially dissolve within one cycle of the washing or dishwashing machine, i.e. within 30 to 120 minutes.
The Applicant has found that by providing a detergent tablet comprising a compressed portion and a non-encapsulating, non-compressed portion detergent components previously considered to be unacceptable for detergent tablets, can be incorporated into a detergent tablet. In addition, potentially reactive components of the detergent composition can be effectively separated.
A further advantage of using a detergent tablet as described herein, is the performance benefits which may be achieved in being able to prepare the detergent tablet so that if required, the compressed portion and the non-compressed portion have different rates of dissolution. Such performance benefits are achieved by selectively delivering active detergent components into the wash solution at different times.
SUMMARY OF THE INVENTION
According to the present invention there is provided a detergent tablet comprising:
(a) a compressed portion comprising an active detergent component; and
(b) a non-compressed, non-encapsulating portion comprising an active detergent component, wherein the detergent tablet comprises an enzyme.
In an alternative embodiment there is also provided a detergent tablet comprising:
(a) a compressed portion comprising an active detergent component; and
(b) a non-compressed, non-encapsulating portion comprising an active detergent component, wherein the weight ratio of compressed to non-compressed portion is greater than 0.5:1 and the detergent tablet comprises silicate.
In another alternative embodiment there is provided a detergent tablet comprising:
(a) a compressed portion comprising an active detergent component; and
(b) a non-compressed, non-encapsulating portion comprising an active detergent component, wherein the weight ratio of compressed to non-compressed portion is greater than 0.5:1 and the detergent tablet has a dissolution rate of greater than 0.33 g/min as determined using the SOTAX dissolution test method described herein.
In yet another alternative embodiment there is provided a detergent tablet comprising:
(a) a compressed portion comprising an active detergent component; and
(b) a non-compressed, non-encapsulating portion comprising an active detergent component, wherein the weight of the detergent tablet is less than 40 g and the detergent tablet has a dissolution rate of greater than 0.33 g/min as determined using the SOTAX dissolution test method described herein.
In yet another alternative embodiment there is provided a detergent tablet comprising:
(a) a compressed portion comprising an active detergent component; and
(b) a non-compressed, non-encapsulating portion comprising an active detergent component wherein the compressed portion provides a mould to accommodate the non-compressed portion.
In addition there is also provided a process for preparing the detergent tablets described herein.
DETAILED DESCRIPTION OF THE INVENTION
Thus, in accordance with the present invention it has been found that active detergent components of a detergent tablet previously adversely affected by the compression pressure used to form the tablets can now be included in a detergent tablet. Examples of these components include bleaching agents and enzymes. In addition, in accordance with the present invention, it has been found that active detergent components of a detergent tablet may be separated from one another by having one or more compatible components contained in a compressed portion and one or more compatible components contained in a non-compressed portion of the tablet. Examples of components that may interact and may therefore require separation include bleaching agents, bleach activators or catalyst and enzymes; bleaching agents and bleach catalysts or activators; bleaching agents and surfactants; alkalinity sources and enzymes.
Furthermore, it may be advantageous to provide the compressed and the non-compressed portions such that they dissolve in wash water with different dissolution rates. By controlling the rate of dissolution of each portion relative to one another, and by selection of the active detergent components in the respective portions, their order of release into the wash water can be controlled and the cleaning performance of the detergent tablet may be improved. For example it is often preferred that enzymes are delivered to the wash prior to bleaching agent and/or bleach activator. It may also be preferred that a source of alkalinity is released into the wash water more rapidly than other components of the detergent tablet. It is also envisaged that it may be advantageous to prepare a detergent tablet according to the present invention wherein the release of certain components of the tablet is delayed relative to other components.
It is also env
Addison Michael Crombie
McGregor Alasdair Duncan
Rowland Barry
Speed Lynda Anne
Douyon Lorna M.
Waugh Kevin L.
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