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Abstract

The invention relates to a method for processing PET polymers in order to form PET pellets. A PET melt is granulated in an underwater granulator in order to form PET pellets, wherein the process water is driven at a temperature below the glass transition temperature of the used PETs in order to produce a golf ball-like surface structure on the pellets during the underwater granulation process. According to the invention, the pellets are separated from the super-cooled process water within a second or less and are subjected to an at least two-stage post-treatment process after the drying process, wherein the pellets are supplied with a gas of a first temperature which is higher than the surface temperature of the pellets for a first period of time, said gas being kept uniformly hot, in a first post-treatment chamber to form nuclei, and the pellets are treated in a second post-treatment chamber to crystallize at a second temperature which is higher than the first temperature over a second period of time which is a multiple of the first period of time.

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First Claim