Granules With Filamentous Coatings

Abstract

The present invention relates to a granule comprising a core and a coating, wherein the core comprises an active compound, and the coating comprises filaments prepared from atomizing a liquid coating composition having the property that the liquid coating composition forms filaments upon atomization.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation of U.S. patent application Ser. No. 10 / 397,986 filed Mar. 26, 2003 which claims priority under 35 U.S.C. 119 of Danish application PA 2002 00473 filed Mar. 27, 2002 and U.S. Provisional application No. 60 / 391,839 filed Jun. 27, 2002, the contents of which are fully incorporated herein by reference.FIELD OF THE INVENTION[0002]The present invention relates to particles comprising a core and a coating, wherein said core comprises an active compound and said coating comprises filamentous substance. The coating of the present invention serves both the purpose of regulating density of the particles and protecting the particle from damage by being able of absorbing impacts on the particle. The invention further relates to a process for the manufacture of such coated particles and to a process for the manufacture of said filamentous substance.BACKGROUND OF THE INVENTION[0003]It is known to the art to incorporate...

AI Technical Summary

Benefits of technology

The filamentous coating effectively reduces dust release and enhances the physical integrity of enzyme granules, allowing for larger particle sizes with minimal weight increase and improved impact resistance.

Problems solved by technology

a) Spray dried products, wherein a liquid enzyme-containing solution is atomized in a spray drying tower to form small droplets which during their way down the drying tower dry to form a continuous film layer which encapsulate the enzyme-containing particles. Very small particles can be produced this way (Michael S. Showell (editor); Powdered detergents; Surfactant Science Series; 1998; vol. 71; page 140-142; Marcel Dekker).

b) Layered products, wherein the enzyme is coated as a layer around a pre-formed inert core particle, wherein an enzyme-containing solution is atomized, typically in a fluid bed apparatus wherein the pre-formed core particles are fluidised, and the enzyme-containing solution adheres to the core particles and dries up to leave a layer of dry enzyme on the surface of the core particle. Particles of a desired size can be obtained this way if a useful core particle of the desired size can be found. This type of product is described in e.g. WO 97 / 23606

c) Absorbed core particles, wherein rather than coating the enzyme as a layer around the core, the enzyme is absorbed onto and / or into the surface of the core. Such a process is described in WO 97 / 39116.

d) Extrusion or pelletized products, wherein an enzyme-containing paste is pressed to pellets or under pressure is extruded through a small opening and cut into particles which are subsequently dried. Such particles usually have a considerable size because of the material in which the extrusion opening is made (usually a plate with bore holes) sets a limit on the allowable pressure drop over the extrusion opening. Also, very high extrusion pressures when using a small opening increase heat generation in the enzyme paste, which is harmful to the enzyme. (Michael S. Showell (editor); Powdered detergents; Surfactant Science Series; 1998; vol. 71; page 140-142; Marcel Dekker)

e) Prilled products, wherein an enzyme powder is suspended in molten wax and the suspension is sprayed, e.g. through a rotating disk atomizer, into a cooling chamber where the droplets quickly solidify (Michael S. Showell (editor); Powdered detergents; Surfactant Science Series; 1998; vol. 71; page 140-142; Marcel Dekker). The product obtained is one wherein the enzyme is uniformly distributed throughout an inert material instead of being concentrated on its surface. Also U.S. Pat. No. 4,016,040 and U.S. Pat. No. 4,713,245 are documents relating to this technique

f) Mixer granulation products, wherein an enzyme-containing liquid is added to a dry powder composition of conventional granulating components. The liquid and the powder in a suitable proportion are mixed and as the moisture of the liquid is absorbed in the dry powder, the components of the dry powder will start to adhere and agglomerate and particles will build up, forming granulates comprising the enzyme. Such a process is described in U.S. Pat. No. 4,106,991 (NOVO NORDISK) and related documents EP 170360 B1 (NOVO NORDISK), EP 304332 B1 (NOVO NORDISK), EP 304331 (NOVO NORDISK), WO 90 / 09440 (NOVO NORDISK) and WO 90 / 09428 (NOVO NORDISK). In a particular product of this process wherein various high-shear mixers can be used as granulators, granulates consisting of the enzyme, fillers and binders etc. are mixed with cellulose fibers to reinforce the particles to give the so-called T-granulate. Reinforced particles, being more robust, release less enzymatic dust (vide infra).