| 摘要 |
1,128,192. Coating inorganic particles. ORGANON LABORATORIES Ltd. 22 Nov., 1965 [4 Dec., 1964], No. 49492/65. Heading C1A. [Also in Divisions A5 and B2] Powders are rendered free flowing by mixing with an amount of a liquid containing an organic coating material sufficient to convert the substance into a moist, non-coherent, non- homogeneous mass the coating material being dissolved or at least swollen in the liquid and completely homogenizing the non-agglomerated mass formed in a grinder of the continuous feed and discharge type, followed by drying the mass if required. The mixing may be carried out in conventional mixers. The grinder may be of the hammer mill type. Examples of coating materials are carbohydrates such as starch, amylopectin, cellulose, methyl-, ethyl-, hydroxyethyl-, ethylhydroxyethyl., sodium carboxymethyl - cellulose, polyvinyl pyrrolidone, gelatine, alginic acid, polysaccharides, natural gums, e.g. guar gum, arabic gum, tragacanth, natural and artificial resins such as shellac, zein, colophonium, polyvinyl and polyacryl resins, polyethylene glycol waxes and mixtures thereof. The liquid may be water, alcohols, ethers, ketones, halogen hydrocarbons. The coating material may be added in the finely-divided, dry state, after which the liquid is added in the required amount, say 1-10% by weight. The substances treated may be aluminium hydroxide, calcium carbonate, basic bismuth nitrate, sulphur, and calcium sulphate. The free flowing powders are suitable for tableting, capsuling when mixed with filling substances, lubricants. In the Examples, free flowing powders are formed by coating powders of (8) calcium sulphate with methyl cellulose, (11) sulphur with methyl cellulose and (13) neutral sodium pyrophosphate with carboxymethyl cellulose. |
