Compositions – Preservative agents – Anti-corrosion
Reexamination Certificate
1999-04-07
2001-03-13
Michl, Paul R. (Department: 1714)
Compositions
Preservative agents
Anti-corrosion
C252S391000
Reexamination Certificate
active
06200498
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a process for producing pourable foam regulator granules containing inorganic, water-soluble and/or water-dispersible carrier salt and paraffin wax for use in laundry and dishwashing detergents by pelletizing and to the use of the granules thus produced as foam-regulating constituents of laundry and dishwashing detergents.
2. Discussion of Related Art
The use of bisamides as foam regulators for detergents is known from DE-A 20 43 087. However, the formulations mentioned in that document do not have a uniform foam regulator effect over a wide temperature range and show weaknesses, particularly at low washing temperatures. European patent EP 087 233 describes a process for the production of a low-foaming detergent in which mixtures of an oily or wax-like substance and bisamides are applied to a carrier powder, more particularly a spray-dried surfactant-containing detergent. The oily or wax-like substance may consist, for example, of vaseline with a melting point of 20° C. to 120° C. In the Examples, mineral oil is used for this purpose. This component obviously serves primarily as a carrier or dispersant for the bisamide. Although the use of 2% by weight of foam-regulating mixture, based on the detergent, gives satisfactory results in the Ross-Miles Test, these quantities appear far too high for practical purposes. In addition, with this method of formulation, i.e. spraying the foam-regulating mixture onto the spray-dried surfactant-containing detergent, the storage stability of the foam regulating component present exclusively on the surface of the foam regulator is in danger of being impaired by the production process, with the result that its activity decreases with increasing storage time. In order to increase its effect and, at the same time, to reduce the necessary in-use concentration, other known foam inhibitors, particularly polysiloxanes or polysiloxane/silica mixtures, are often added to these foam regulators. However, polysiloxanes, although well-known for their favorable foam-regulating effect, are relatively complicated to produce, which generally makes them more expensive as raw materials than comparable active substances, and in addition have the disadvantage that their biological degradability in the wastewater is often not entirely satisfactory. Other bisamide-containing formulations are known from European patents EP 075 437 and EP 094 250. However, the formulations described in these documents contain silicones. DE-A 28 57 155 describes detergents with a foam regulator which contains hydrophobic silicon dioxide and a mixture of solid and liquid hydrocarbons, optionally in admixture with fatty acid esters. European patent application EP 309 931 describes foam regulators based on a relatively expensive mixture of paraffin wax and microcrystalline paraffin wax. International patent application WO 93/17772 describes paraffin-based foam regulators containing carboxylic acid bisamide of which the paraffin wax component has as small a liquid content as possible and, preferably, contains no liquid at all. According to the document in question, preferred paraffin wax mixtures have a liquid content at 30° C. of less than 10% by weight and a liquid content at 40° C. of less than 30% by weight. In some cases, however, foam regulators of the type in question perform unsatisfactorily in low-temperature machine washing which, recently, has acquired increasing significance.
European patent application EP 0 008 829 describes solid detergents which contain a foam control system of wax, hydrophobicized silica gel, certain nonionic dispersants and, optionally, silicones which is present in the form of an intimate mixture with the other ingredients of the detergent. According to the document in question, the preliquefied foam control system may be sprayed onto preformed, more particularly spray-dried, carrier granules which contain all or part of the other detergent ingredients. The several stages involved in this production process make it relatively complicated.
DE-A 34 36 194 describes a process for the production of pourable foam regulator granules by spray drying of an aqueous dispersion containing water-insoluble foam inhibitor, inorganic carrier salt and certain cellulose ether mixtures. Because of the high temperatures prevailing under the spray-drying conditions, a process such as this can lead to products which do not always show optimal foam-regulating performance, particularly where low-melting paraffin waxes are used.
However, the use of such low-melting paraffins is of particular interest by virtue of their considerable effectiveness in the low-temperature wash programs being increasingly used by the consumer.
Additionally, there was a need to develop a process for the production of stable foam regulator formulations which, in the production of particulate laundry and dishwashing detergents, would withstand mixing with the other ingredients with their granular structure intact and without any dust emission and which, nevertheless, would dissolve quickly and completely and release the foam-inhibiting agent under in-use conditions.
DESCRIPTION OF THE INVENTION
The process according to the invention for producing pourable foam regulator granules containing a defoamer combination of a paraffin wax and a bisamide derived from diamines and carboxylic acids and inorganic, water-soluble and/or water-dispersible carrier salt is characterized in that a pelletizing step is carried out in a granulation mixer by intensively mixing a quantity of 50 to 100 parts by weight and, more particularly, 60 to 85 parts by weight of the inorganic carrier salt, preferably containing alkali metal sulfate and/or alkali metal carbonate, optionally with a quantity of up to 5 parts by weight and, more particularly, 1 to 3 parts by weight of an anionic and/or nonionic cellulose ether, adding a quantity of 1 to 10 parts by weight and, more particularly, 2 to 8 parts by weight of an aqueous alkali metal silicate and/or polymeric polycarboxylate solution while granulation continues and then adding 10 parts by weight of the defoamer combination heated to a temperature of 70° C. to 180° C. In a preferred embodiment, 5 to 20 parts by weight and, more particularly, 7 to 15 parts by weight of water or an aqueous sodium silicate and/or polymeric polycarboxylate solution are added after the defoamer combination. In these cases, the granules obtained have a particularly stable structure. It is remarkable that, where this procedure is adopted, the carrier material does not have to heated and, instead, can be left at ambient temperature or at the temperature generated by the energy introduced through the mixing process.
In another preferred embodiment of the process according to the invention, the preferably phosphate-free carrier salt mixture is homogenized, optionally after addition of the cellulose ether mixture, for 5 seconds to 30 seconds, more particularly in an intensive mixer, for example an FS30 Fukae® an Eirich® mixer, a Lödige® plowshare mixer or a Shugi® mixer, the aqueous alkali metal silicate solution is added as quickly as possible, the liquid molten defoamer combination is then introduced, after which the water or the aqueous alkali metal silicate and/or polycarboxylate solution, if any, is added over a period of 10 seconds to 30 seconds and the granulation process is continued for 10 seconds to 10 minutes. The ingredients used in liquid form can be introduced through the spray nozzles normally present in granulation mixers.
The defoamer combination preferably consists of 70% by weight to 95% by weight of paraffin wax or paraffin wax mixture and of 5% by weight to 30% by weight of a bisamide derived from C
2-7
diamines and saturated C
12-22
carboxylic acids. The paraffin wax is solid at room temperature, at least 35% by weight and, more particularly, at least 45% by weight and less than 100% by weight preferably being present in liquid form at a temperature of 40° C.
The paraffin wax present in the defoamer combi
Artiga Gonzalez Rene-Andres
Hammelstein Stefan
Kraus Ingrid
Liphard Maria
Henkel Kommanditgesellschaft auf Aktien
Jaeschke Wayne C.
Michl Paul R.
Murpjy Glenn E. J.
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