Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Patent
1996-06-04
1998-11-03
Geist, Gary
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
424466, 424489, 426 96, 53205, 127 21, 4234191, 423422, 423421, 75 1057, C07C 59265, A61K 946, A61K 914
Patent
active
058311238
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a process for continuously producing a granulated material from a powder mixture comprising at least two components.
Such a process is described, for example, in CH-A-478 591. This prior art states that wet granulation can scarcely be carried out, particularly in the case of reactive components of a powder. It is therefore said to be difficult to granulate, for example, zinc white without a binder. This publication envisages the solution as a cold granulation utilizing adhesive forces which are to be generated by deflecting the powder by baffles and by other purely mechanical means.
In practice, such a process proves to be very unreliable, and a uniform particle size of the resulting granulated material is also not ensured. It is therefore the object of the invention to design a process of the type stated at the outset so that relatively large amounts of granulated material can be obtained in a satisfactory quality by means of said process. According to the invention, this is achieved in a surprisingly simple manner by surface adhesion of the components of the powder mixture with the aid of water as a superficially active adhesive solution, as described below.
WO 86/07547, the most closely related prior art, describes a process for producing granules of effervescent powder, wherein a hot air stream is forced over or through the powder mixture and is intermittently sucked off again. The powder mixture is first dried by dry or slightly moist hot air and application of reduced pressure and is then adhesively bonded at the surface by treatment with hot steam and the consequent partial reaction of the powder components with one another, for example citric acid with calcium carbonate to give calcium citrate. This process with its extremely difficult humidity adjustment could be carried out to date only in batch operation, with one or more moistening and drying phases performed in succession.
In comparison, the present invention constitutes a remarkable improvement of moist granulation. According to the basic continuous process for producing granulated material from a powder mixture and the various embodiments described herein, the water required for the surface adhesion is liberated inside the drum, optionally by a partial reaction of the relative component(s) of the powder mixture.
This solution is surprising for several reasons. On the one hand, the teaching according to the invention is precisely contradictory to that of the stated prior art, which wanted as far as possible to avoid moisture, in fact just to avoid reactions. On the other hand, the invention deliberately starts from a reaction, albeit only a partial one, of the reactive components, namely to an extent such that the superficial accumulation of the components, i.e. the granulation, can be carried out.
On the other hand, complete reaction of the reactive components must be feared in many cases, as was evidently also by the author of the above-mentioned prior art. The invention is therefore also based on the knowledge that this effect does not occur if water or the liquid partially triggering the reaction is used only in such small amounts that they at least approximately correspond to the amount of water of crystallization of at least one of the powder components. In individual cases, it may even be possible to exceed these small amounts by about 100%, for example by external supply of moisture.
It is here that a third surprising feature is also encountered, since the difficulty of controlling the reaction has to date prevented those skilled in the art from arriving at a continuous, and hence more economical, process. Particular effervescent granules were first prepared batchwise on tray dryers or in separate fluidized beds of the acidic and the basic component, or in a vacuum granulator. High daily outputs were therefore virtually impossible to achieve. This problem of the control of the reaction, and hence the possibility of a continuous and economical process, is solved by the measures acco
REFERENCES:
patent: 3101040 (1963-08-01), Lanz
patent: 3340018 (1967-09-01), Otrhalek
patent: 4678661 (1987-07-01), Gergely et al.
patent: 4876802 (1989-10-01), Gergely et al.
patent: 4911930 (1990-03-01), Gergely et al.
Gergely Gerhard
Tritthart Wolfram
Geist Gary
Gergely Gerhard
Keys Rosalynd
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