Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Solid – shaped macroscopic article or structure
Reexamination Certificate
2000-05-10
2002-08-27
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, C510S475000, C510S505000
Reexamination Certificate
active
06440927
ABSTRACT:
TECHNICAL FIELD
The present invention relates to detergent tablets having multiple-layers and, more particularly, to multi-layer detergent tablets having both compressed and non-compressed portions.
BACKGROUND OF THE INVENTION
Detergent compositions in tablet form are known in the art. Detergent compositions in tablet form hold several advantages over detergent compositions in particulate or liquid form, such as ease of use and handling, convenient dosing, ease of transportation and storage. Due to these advantages, detergent compositions in tablet form are becoming increasingly popular with consumers of detergent products.
Detergent tablets are most commonly prepared by pre-mixing the components and forming the pre-nixed components into a tablet via the use of a tablet press and compression of the components. However, traditional tablet compression processes have significant drawbacks, including but not limited to the fact that selected components of a detergent composition may be adversely affected by the compression pressure in the tablet press. Accordingly, these selected components were not typically included in prior art detergent tablets without sustaining a loss in performance. In some cases, these selected components may even have become unstable or inactive as a result of the compression.
In addition, as the components of the detergent composition are compressed in the tablet press, they are brought into close proximity with one another resulting in the reaction of selected component, instability, inactivity or exhaustion of the active form of the components.
To avoid the above mentioned drawbacks, prior art detergent tablets have attempted 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 reactive components are contained in different layers of the tablet or encapsulation and coating of reactive components. These prior art multiple-layer tablets are traditionally prepared using multiple compression steps. Accordingly, layers of the tablet which are subjected to more than one compression step may be subjected to a cumulative and potentially greater overall compression pressure. In addition, 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 tablets may not dissolve satisfactorily in use. Nor is there any sinificant variation in the dissolution rates of the multiple layers.
Accordingly, the need remains for an improved detergent tablet, which can deliver active detergent ingredients to a domestic wash process thereby delivering superior performance benefits.
SUMMARY OF THE INVENTION
This need is met by the present invention wherein a multi-layer detergent tablet having a compressed body portion and a non-compressed gelatinous portion is provided. The tablet of the present invention provides a superior delivery mechanism for detergent components in addition to effectively separating potentially reactive ingredients. In addition, the detergent tablet of the present invention provides superior cleaning performance, particularly in domestic, automatic dishwashing machines over the tablets of the prior art.
According to a first embodiment of the present invention, a detergent tablet is provided. The tablet comprises:
A) a compressed solid body portion having at least one mold in the compressed body portion; and
B) a non-compressed, gelatinous portion mounted in the mold of the compressed body portion, wherein the gelatinous portion comprises a thickening system and at least one detergent active.
Preferably, the gelatinous portion is formulated so that at least 80% of the detergent active is delivered to the wash within the first 5 minutes of a domestic wash process, and more preferably at least 90% of the detergent active is delivered to the wash within the first 3 minutes of a domestic wash process. The detergent active in the gel portion may be selected from the group consisting of enzymes, surfactants, disrupting agents, bleaching agents, silver care agents, builders, and mixtures thereof with enzymes and disrupting, agents being the most preferred. When a disrupting agent is included, the disrupting agent is preferably a salt of carbonate or bicarbonate and an organic acid.
In alternative preferred embodiments, the gel portion contains at least about 15% suspended solids and more preferably at least about 40% of the gelatinous portion is a suspended solid. The gelatinous portion may further includes a swelling/adsorbing agent.
The thickening system of the present invention preferably comprises a mixture of a non-aqueous diluent or solvent and a gelling agent. The gelling agent may be selected from the group consisting of castor oil derivatives polyethylene glycol and mixtures thereof and is preferably polyethylene glycol. The non-aqueous diluent may be selected from the group consisting of low molecular weight polyethylene glycols, glycerol and modified glycerols, propylene glycol, alkyleneglycol alkyl ethers and mixtures thereof and is preferably dipropyleneglycol butylether propylene glycol or glycerol triacetate.
Lastly, the weight ratio of the compressed portion to the non-compressed gelatinous portion is preferably greater than about 0.5:1 and the compressed portion of the detergent tablet preferably has a dissolution rate of greater than 0.33 g/min as determined using the SOTAX dissolution test method.
Accordingly, it is an object of the present invention to provide a multi-layer detergent tablet having at least one compressed portion and at least one non-compressed gelatinous portion. It is a further object of the present invention to provide a gel portion which can quickly and efficiently deliver detergent actives to a domestic wash process. It is still further an object of the present invention to provide a detergent tablet having a gel portion which is a pumpable, flowable solid at slightly elevated temperature yet hardens or thickens to maintain its form at ambient temperatures, particularly when shear is removed from the gel. These, and other objects, features and advantages of the present invention will be readily apparent to one of ordinary skill in the art from the following detailed description and the appended claims.
All percentages, ratios and proportions herein are by weight, unless otherwise specified. All temperatures are in degrees Celsius (° C.) unless otherwise specified. All documents cited are in relevant part, incorporated herein by reference.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention comprises a multi-phase detergent tablet and in particular a detergent tablet for automatic dishwashing which has a least one compressed body portion and a least one gelatinous or gel portion which is non-compressed. The use of the gel portion provides a superior delivery mechanism for detergent active agents into the domestic wash process. The gel portion provides unique properties of rapid dissolution or dispersion thereby providing for the earliest possible delivery of detergent active agents into the domestic wash process.
Accordingly, by way of the present invention, active detergent components of a detergent tablet previously adversely affected by the compression pressure used to form the tablets may now be included in a detergent tablet. Examples of these components include bleaching agents and enzymes. In addition, these active detergent components may be separated from one another by having one or more compatible components contained in the compressed portion and one or more compatible components contained in the non-compressed, gel 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 source
Foley Peter Robert
Metzger-Groom Sabine Ursula
Painter Jeffrey Donald
Song Xiaoqing
Speed Lynda Anne
Bolam Brian M.
Douyon Lorna M.
The Procter & Gamble & Company
Waugh Kevin L.
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