Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Solid – shaped macroscopic article or structure
Reexamination Certificate
2000-05-10
2002-11-26
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, C510S392000, C510S505000, C008S137000, C134S025200
Reexamination Certificate
active
06486117
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 bold 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-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 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 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 multi-layer detergent tablet having a compressed solid 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 laundry or 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:
i) a compressed solid body portion having at least one mold in the compressed solid body portion;
ii) a non-compressed, gelatinous portion mounted in the at least one mold of the compressed solid body portion, the gelatinous portion comprising a thickening system and at least one detergent active; and
wherein the non-compressed, gelatinous portion has a yield strength of from about 5 to about 80 Pa before the non-compressed, gelatinous portion is mounted in the at least one mold.
According to a second embodiment of the present invention, a detergent tablet is provided. The tablet comprises:
i) a non-compressed, gelatinous portion mounted in the at least one mold of the compressed solid body portion, the gelatinous portion comprising a thickening system and at least one detergent active; and
wherein the non-compressed, gelatinous portion has an average viscosity of from about 100 to about 12000 cP before the non-compressed, gelatinous portion is mounted in the at least one mold.
The viscosities and yield strengths were determined on a Paar Physica disc and plate viscometer, with a distance between the disc and plate of 0.5 mm at standard conditions. The viscosities are from about 100 to about 12000 cP(centipoise), preferably from about 100 to about 7000 cP, more preferably from about 100 to about 2000 cp. The yield stress is from about 5 to about 80 Pa. The non-compressed, gelatinous portion upon mounting can harden many ways including, but not limited to, cooling, removal of shear force, or even crosslinking of monomers/polymers present in the non-compressed, gelatinous portion.
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 may contain 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
Foley Peter Robert
Metzger-Groom Sabine Ursula
Painter Jeffrey Donald
Song Xiaoqing
Speed Lynda Anne
Douyon Lorna M.
The Procter & Gamble & Company
Waugh Kevin L.
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