PET cristallisation CrystallCut®

CrystallCut® was developed to produce free flowing crystallized PET granulate, gently and economically. In the conventional crystallization process, PET granulate has had a tendency to crystallize with a lack of homogeneity – the amorphous part is too high, and the degree of crystallization very low.

Since amorphous PET has the tendency to stick together, it has been a severe problem. To crystallize the material sufficiently, it was necessary to supply the crystallization process with sufficient energy or heat. Till now PET recycling has been more difficult and expensive – the introduction of CrystallCut® offers economic PET recycling.

Advantages of CrystallCut®

• degree of crystallization approx. 40%
• almost dust-free product
• up to 8% higher bulk density
• lower energy consumption
• reduced production costs
• direct transportation into the SSP possible
• quick start-up of the line and change of product
• due to the even crystallinity, the PET cannot stick together

Description CrystallCut® Example: PET recyling

We start at the point where the PET melt has been extruded by the die and cut by the face cutter. The cut hot PET granulate is now rapidly transported in hot water (of up to 95°C) to a pellet dryer in the closed conveying pipes, where pellet cooling and solidifying takes place.

Important criteria in the effectiveness of Crystall- Cut® are the conveying medium and relatively short conveying distances between the die head and the pellet dryer. PET pellets exit the pellet

dryer at a temperature of about 150–160°C onto a vibrating conveyor which is designed in a similar way to oscillating separators of undersize and oversize pellets (but there are no sizing screens). The conveyor is divided into several zones, the vibrators keeping the pellets in permanent motion which enables them to pass on their energy to other pellets. In each zone, circulation of PET pellets stops them sticking together. At the completion of the process the PET pellets will have attained a degree of crystallinity of up to 40%. They have a temperature of approximately 180 °C and may be transferred directly into a SSP.