Cleaning and liquid contact with solids – Processes – Miscellaneous
Reexamination Certificate
2000-01-10
2002-01-08
Kopec, Mark (Department: 1751)
Cleaning and liquid contact with solids
Processes
Miscellaneous
C510S191000, C510S192000, C510S193000, C510S403000, C510S470000, C134S039000
Reexamination Certificate
active
06336977
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a gel-form cleaner which may be used with advantage in flush toilets.
2. Discussion of Related Art
It is known that solid cleaning compositions in block form are used for automatically keeping toilets clean. These cleaning blocks are arranged either in the lavatory bowl or in the cistern. Water flows over the blocks each time the toilet is flushed so that the blocks gradually dissolve and, in doing so, release their cleaning ingredients. Normally, the cleaning blocks also contain fragrance to perfume the surrounding environment or disinfecting agents to optimize hygiene. The described cleaning blocks are applied in suitable containers, in some cases in special refillable containers.
The described cleaning blocks are generally produced by casting, compression, extrusion or granulation processes which involve a high outlay on equipment and which often suffer unwanted losses of perfume through the high temperatures involved (casting/extrusion processes).
Another disadvantage is that the refill units, which are widely used for ecological reasons, can only be employed after the cleaning block has been used up. Selective refilling which would be desirable, for example, to intensify the release of active ingredients or, more particularly, to release more perfume is not possible.
The problem addressed by the present invention was to provide a system which would not have any of the disadvantages described above. It has now surprisingly been found that special gel-form preparations with pseudoplastic properties significantly reduce the outlay on production equipment and can be produced less expensively by a simple process. The problem of individual refillability can also be solved by the pseudoplastic active-substance preparations according to the invention. A special container, which is particularly suitable for the gel-form cleaning compositions according to the invention, is described in DE-A-195 201 45.
DESCRIPTION OF THE INVENTION
The present invention relates to a stable, gel-form and shear-thinning cleaning composition which, in addition to a polysaccharide, contains a C
8-22
alkyl polyglycoside as its surfactant system and perfume components, the composition containing a polysaccharide in quantities of 1 to 5% by weight as one component of the surfactant system, a C
8-22
alkyl polyglucoside in quantities of 3 to 25% by weight, the perfume component(s) in quantities of 2 to 15% by weight and optionally other ingredients, such as co-surfactants, lime-dissolving agents, dyes, germ inhibitors, pearlescers, stabilizers, cleaning boosters and odor absorbers and having a viscosity in the range from 30,000 to 150,000 mPas (as measured with a Brookfield RVT rotational viscosimeter with a Helipath spindle and TA spindle at 1 r.p.m./23° C.).
It has been found that visually attractive, translucent or clear pseudoplastic gel structures, which are as stable as solid rim blocks in suitable containers, can only be obtained with polysaccharides in the described combinations, depending on the types selected with high perfume and APG concentrations.
Other standard gel formers such as, for example, polyacrylic acid (Carbopol), surfactant-thickened systems, MHPC (Natrosol) or sodium- chloride- or electrolyte-thickened surfactant systems do not show adequate gel stability where the high surfactant and perfume levels required are used. These formulations are often not sufficiently pseudoplastic, are diluted by water flowing over them and, on account of their inadequate viscosity behavior, drip uncontrollably into the lavatory bowl despite suitable containers. By contrast, the formulations according to the invention are decidedly pseudoplastic and withstand the water flowing over them to the extent that only small amounts are released and the required stability is obtained. This is because the compositions should also not dissolve too readily in the water penetrating into their containers, otherwise they would be dissolved and therefore exhausted after only a small number of flushes.
In addition, it is important to ensure that, despite the high concentrations of perfume and emulsifier, the gels are guaranteed adequate long-term stability and, for example, do not separate into phases which would not only diminish their visual appeal to the consumer, it would also impair dissolving kinetics and dose control.
Another advantage is that the viscosity of the compositions decreases with increasing shear rate so that they can be packed in containers during the production process and are easy to handle by the consumer during dosing/refilling.
Surprisingly, it has also been found that, under certain conditions in the production process, air bubbles can be introduced into the compositions according to the invention and retain their shape and size over a period of several weeks so that the end product becomes even more attractive to the consumer.
The size of the air bubbles, which can be controlled for example through the stirring rate in the production process and through the viscosity of the compositions, should be neither too large nor too small. In addition, the quantity of air bubbles should only be selected in a preferred range. If, therefore, the presence of air bubbles should be desirable, no more than 30% volume of air should be present, air volumes of 2 to 25% by volume being preferred and air volumes of 5 to 20% by volume being particularly preferred. Particularly preferred embodiments contain air bubbles between 0.1 mm and 20 mm in diameter, air bubbles between 1 mm and 15 mm diameter being most particularly preferred.
However, the viscosity of the compositions according to the invention also enables the air bubbles already introduced in the production process to be removed by brief application of a reduced pressure which may be in a range just below ambient pressure to approaching a vacuum. The duration of the reduced pressure treatment will depend on the strength of the reduced pressure. If a relatively strong reduced pressure is applied, the treatment need not be continued for very long. However, the expert also knows that an excessive reduced pressure can result in unwanted side effects including, for example, the intensified evaporation of readily volatile perfume components and, in some cases, problems affecting the stirrability of the system. Although the compositions according to the invention can be degassed by treatment in a centrifuge or by ultrarapid stirring, such treatments are not preferred.
This is because, if possible, the compositions according to the invention should not be exposed to excessive shear forces during or after the production process because otherwise the properties according to the invention would often be lost in the short to medium term and could only be recovered after long waiting times.
The formulations according to the invention may be produced in various ways and in various batch sizes up to, and including, several tonnes.
Normally, water is introduced into a commercially available mixer, for example a Beco-Mix, and the dye is stirred in. The xanthan gum preferably used as the polysaccharide is separately suspended with solvent, preferably ethanol, and the required perfume oil. The suspension is then added and the whole is stirred at low speed, for example at 30 r.p.m.
Investigations have shown that, after all the components have been added, a time of a few minutes to a few hours is required to reach the consistency according to the invention. In the present case, the surfactant (alkyl polyglycoside) was slowly added after 30 minutes. The other components are then added. If a bubble-free gel is to be guaranteed, the mixture has to be placed under a reduced pressure or under a vacuum, as described above, in a suitable container in dependence upon its viscosity, but generally for a short time, for example 15 minutes.
However, other procedures may be adopted. This is advisable, for example, where disinfectants are to be included. In this case, water is normally introduced into a commer
Ditze Alexander
Menke Ronald
Pessel Frank
Henkel Kommanditgesellschaft Auf Aktien (KGaA)
Jaeschke W. C.
Kopec Mark
Mruk Brian P.
Murphy Glenn E.J.
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