Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Solid – shaped macroscopic article or structure
Reexamination Certificate
2000-05-10
2002-07-02
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, C510S392000, C510S475000
Reexamination Certificate
active
06413928
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a process for the preparation of detergent tablets having multiple-layers and, more particularly, to detergent tablets having both compressed and gelatinous 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 case 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-mixed 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 components, 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 significant 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 process for the preparation of a detergent tablet having a tablet body and a gelatinous portion is provided. The process of the present invention provides a detergent tablet having a superior delivery mechanism for detergent components in addition to effectively separating potentially reactive ingredients. A detergent tablet prepared by the process of the present invention is also provided for. The detergent tablet produced 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 process for preparing a multi-phase detergent tablet is provided for comprising the steps of:
a) forming a tablet body by compressing a granular detergent mixture, said tablet body having a first surface, said first surface having at least one mold therein and said granular detergent mixture comprises at least one detergent active agent;
b) providing a gelatinous mixture under constant agitation, and delivering said gelatinous mixture to said at least one mold in said tablet body to form a gelatinous portion, said gelatinous mixture comprises at least one detergent active agent; and
c) hardening or curing said gelatinous portion to form a multi-phase detergent tablet.
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 agent in the gelatinous portion may be selected from the group consisting of enzymes, surfactants, drying agents, alkalinity source, 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 gelatinous portion contains at least about 15% suspended solids and more preferably at least about 40% of the gelatinous portion is a suspended solid. The gel portion may further include 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 tablet body to the non-compressed gelatinous portion is preferably greater than about 0.5:1 and the tablet body 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 aspect of the present invention to provide a process for preparing a detergent tablet having a tablet body which is formed by compression of a granular detergent mixture. The tablet body having a first surface, and the first surface having at least one mold therein. A gelatinous mixture is then formed and added to the at least one mold forming a gelatinous portion therein. Hardening or curing the gelatinous portion to form a multi-phase detergent tablet. It is a further aspect of the present invention to produce a detergent tablet containing a gelatinous portion which can quickly and efficiently deliver detergent actives to a domestic wash process. It is still further an aspect of the present invention to provide a process of preparing a detergent tablet having a gelatinous portion which is a pumpable, flowable solid in liquid mixture or suspension, at slightly elevated temperature yet thickens or hardens to maintain its form at ambient temperatures, particularly when shear is removed from the gelatinous mixture. These, and other aspects, 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.
Definition
The term “gelatinous mixture” as used herein means that the mixture upon, cooling, being cooled, hardening, removing from agitation, or curing becomes gelatinous. That is, it forms the gelatinous portion which is gelatinous. The gelatinous mixture can be any possible type of mixture provided that on cooling, hardening, removing from agitation or curing, it becomes gelatinous. For example, the gelatinous mixture could be a liquid, a solid in liquid mixture/suspension or even a gel.
DETAILED DESCRIPTION OF T
Binder Christopher James
Painter Jeffrey Donald
Smith David John
Thien Joseph Herbert
Douyon Lorna M.
Robinson Ian S.
The Procter & Gamble & Company
Waugh Kevin L.
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