Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Heterogeneous arrangement
Reexamination Certificate
1999-02-24
2001-04-03
Douyon, Lorna M. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Heterogeneous arrangement
C510S444000, C510S299000, C510S400000, C510S466000, C510S501000, C510S509000, C510S511000
Reexamination Certificate
active
06211136
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a process for the production of pourable and free-flowing granular detergent ingredients which contain an active substance liquid at room temperature and a fine-particle carrier material for that active substance, and to the use of granules produced by this process for the production of solid detergents.
2. Discussion of Related Art
Modern detergents contain a number of ingredients which, besides those essential to the washing process, such as surfactants and builders, generally include other constituents which can come from such different groups of active substances as foam regulators, redeposition inhibitors, soil release agents, bleaching agents, bleach activators and dye transfer inhibitors. Besides this classification of active substances, typical detergent ingredients can also be classified according to their aggregate state at room temperature. Accordingly, a distinction may be drawn between solid and liquid ingredients of detergents. The percentage content of liquid ingredients in solid powder-form detergents should naturally not exceed a certain upper limit because otherwise the individual particles would cake together, the flowability of the detergent and its pourability from the box would no longer be guaranteed and the detergent would become far more difficult to dose and handle by the user. Accordingly, constituents liquid at room temperature are normally incorporated in powder-form detergents in the form of mixtures with solid absorbent carrier materials. Various processes are available for the production of such compounds of solid, powder-form carrier material and liquid active substance. For example, aqueous slurries of carrier material and liquid active substance can be spray-dried. This process is attended by difficulties where substances insoluble in water or not readily dispersible in water are to be processed. In addition, it is limited to substances which have a certain heat resistance and, in addition, has the disadvantage that removal of the water entails relatively high energy consumption. An alternative production process comprises, for example, applying liquids to particles of carrier material moved in a mixer. If the active substances involved are liquid at the temperature of the particulate carrier material, the carrier material to which the liquids are applied is in danger of agglomerating, which leads to a not always desirable increase in the size of the particles, and the particles are in danger of caking on the walls of the mixer. One way of avoiding these dangers is to use a fluidized bed of the carrier material to which the liquid is applied. In this case, however, it is important to bear in mind that a fluidized bed cannot be produced from every substance suitable for use as a solid carrier material and that, in many cases, the particles forming the fluidized bed cannot always be completely prevented from agglomerating.
The problem addressed by the present invention was to provide an alternative production process for granular detergent ingredients containing an active substance at least partly liquid at room temperature and a fine-particle carrier material in which these disadvantages would be avoided.
DESCRIPTION OF THE INVENTION
It has now surprisingly been found that this problem can be solved by using a spray coater which, hitherto, has been used in particular in the so-called Rotocoat® process, providing certain basic conditions are fulfilled in regard to the particle size of the carrier material to be sprayed.
The present invention relates to a process for the production of pourable and free-flowing granular detergent ingredients containing an active substance at least partly liquid at room temperature and a fine-particle carrier material for that active substance, characterized in that the carrier material, which has a mean particle size of 3 &mgr;m to 0.5 mm, is allowed to drop onto a rotating disk where it is radially accelerated by vanes arranged on the upper surface of the disk and in that the liquid active substance is applied to the stream of particles through an annular slot which is formed by the outer edge of the rotating disk and the stator surrounding the disk.
The invention advantageously makes use of the known measures of the Rotocoat® process used for processing completely different materials. The Rotocoat® process and the associated coater are described, for example, in an information sheet entitled “Sandvik Rotocoat® Process: Solvent-free Coating and Agglomeration” published by Sandvik Process Systems in September 1993. This process is a continuous coating process in which a powder-form carrier material drops down onto a horizontally mounted rotating disk. By means of vanes arranged on the upper surface of the disk, the powder is radially accelerated by the centrifugal force so that a particle stream is formed.
The liquid to be applied to the carrier material issues from an annular slot formed by the outer edge of the rotating disk and the stator surrounding the disk and impinges on the stream of particles flowing over the disk. The wetted particles are then taken up by an airstream by means of which they are discharged from the spray coater. Hitherto, this process—as described in the cited information sheet—was confined to the use of coating materials which are liquid at elevated temperatures and solid at room temperature. Coating materials such as these were used in heated, i.e. molten, form in the Rotocoat® process and, after impinging on the carrier material, solidified at the latest on entrainment by the cold airstream. In contrast to this known procedure, a substance which is both liquid at the processing temperature and at least partly liquid at room temperature or a mixture of such substances is used in the process according to the invention.
Accordingly, the present invention also relates to the use of a Rotocoat® coater for applying detergent ingredients at least partly liquid at room temperature to a fine-particle carrier material.
Quite high percentages of the material to be applied, for example not more than 80% by weight and, more particularly, up to 70% by weight, present in solid form at room temperature can be tolerated in the process according to the invention, particularly if the component solid at room temperature is present in liquid form at the processing temperature, i.e. on entry into the spray coater. In cases such as these, it is important to ensure that a homogeneous mixture of the component liquid at room temperature and the component solid at room temperature is used, for example in the form of a solution of one component in the other. If the component which is solid at room temperature does not dissolve completely, if at all, in the component liquid at room temperature, even after melting, as is the case for example with solid paraffins and liquid silicone oils, the mixture of molten component solid at room temperature and the component liquid at room temperature should be stirred until just before it enters the spray coater in order to achieve uniform application of the heterogeneous coating material to the carrier material. The use of solvents, i.e. more or less readily volatile substances which have to be removed by fairly intense heating after application of the coating material, is not preferred.
The nature of the particulate carrier material is not critical. Suitable particulate carrier materials are both inorganic detergent ingredients, such as alkali metal carbonates, alkali metal hydrogen carbonates, alkali metal sulfates, alkali metal phosphates, alkali metal silicates, zeolites (A, P and/or X), alkali metal perborates and/or alkali metal percarbonates, and organic materials, such as citric acid, alkali metal citrates and/or starch, and mixtures thereof. In the alkali metal salts mentioned, sodium is the preferred cation although the potassium and lithium salts may also be used. The mean particle size of the carrier material is preferably in the range from 3 &mgr;m to 100 &mgr;m and more preferably
Beujean Hans-Josef
Richter Bernd
Seiter Wolfgang
Douyon Lorna M.
Henkel Kommanditgesellschaft auf Aktien
Jaeschke Wayne C.
Murphy Glenn E. J.
LandOfFree
Process for preparing granular detergent components does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for preparing granular detergent components, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for preparing granular detergent components will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2520456