Patent ID: 7208107
Filing Date: 2007-04-24
Classification: B01J,B29B,B29C,B29K

Abstract:
1. A method of producing spherical particles from a polymer melt, made of polyfunctional carboxylic acids and alcohols, including PET or PBT pellets, a molten prepolymer and/or precondensate and/or non-stringy polymer being dripped into droplets using a drip nozzle, the droplets having a gas applied to them such that the droplets in the fall tower fall in an essentially laminar portion of the air flow, which runs in counter flow to the falling direction of the droplets, directly after leaving the nozzle part for at least partial crystallization and then being transported to a further post-crystallization stage, characterized in that the molten polymer is dripped using a nozzle plate set into vibration and/or through direct vibration excitation of the molten prepolymer and/or polymer and the droplets thus formed have air applied to them as the gas in counterflow, the air being supplied to the fall tower at a temperature T 1 ≦160° C., which lies above the glass transition point of the prepolymer and/or polymer melt to be dripped and the air is heated to a temperature T 2 ≦210° C. through thermal transfer from the droplets.