Economically viable bottle-to-bottle recycling of PET bottles

Economically viable bottle-to-bottle recycling becomes possible for the first time ever: In co-operation with the B�hler Technology Group, Schmalbach-Lubeca has developed an improved recycling system for the production of new beverage bottles from post-consumer PET containers. Under the system reclaimed PET bottle flake can be pelletized without predrying using a 12-screw "ring" extruder.

The improved process has the advantage that recycled PET pellets can now be offered at an even more attractive price than before, and that they are of equivalent quality to virgin material.

The Model RE ring extruder will be part of an upgraded continuous recycling system for food-grade PET. The Model RE has 12 corotating, closely intermeshing screws arranged in a circle. The system will feed washed PET flake without predrying into the Buhler ring extruder, which will remove moisture along with any organic impurities or volatiles. Melt will then be pelletized and sent into a continuous solid-state polycondensation process, also engineered by Buhler, raising the PET's I.V. to bottle grade again.

Schmalbach-Lubeca developed the Supercycle technology, with which post-consumer PET bottles can be turned into food-grade PET pellets in a two-stage process.

Compared to the existing process, the optimized Supercycle process, which is based on the B�hler bottle-to-bottle recycling technology, has the advantage that two previously separate function steps were combined and developed into one continuous process:

		In a ring extruder, the post-consumer PET material is dried and freed completely from any organic impurities, such as flavours.
		In the continuous solid state polycondensation (SSP) process, the polyester is refined to plastic pellets of greater material strength and thus gains the same properties as virgin PET pellets.

The combination of these two functions increases output and reduces both energy consumption and production cost at the same time. In addition, the process is particularly environmentally compatible, since it is based exclusively on thermal and mechanical process stages without the need for chemical treatment of the material.

The US FDA has approved this bottle-to-bottle recycling system. The resulting PCR-PET is acceptable for contact with all types of food, even when hot-filled or pasteurized above 150° F.

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