Gneuß: Open House and Polyester Recycling Forum well attended

Both the Open House at Gneuss Kunststofftechnik GmbH on October 4th and the Polyester Recycling Forum organised by Dr. Thiele on October 5th 2011 in Bad Oeynhausen, Germany were extremely well visited. More than 140 customers watched demonstrations of extrusion equipment and attended presentations related to PET recycling.

Prior to this year´s Polyester Recycling Forum, Gneuss Kunststofftechnik GmbH, based in Bad Oeynhausen invited all the visitors to the PRF and all those who were interested to visit their new processing technical facility.

The visitors showed great interest in the demonstration of an extrusion line for the manufacture of PET sheet for thermoforming from 100 % bottle flake without any pre-treatment of the material. This pilot / production line was used to process washed bottle flake from typical sources to a food contact grade sheet for thermoforming. The flakes were fed without any pre-drying or crystallising via gravimetric dosing systems from Woywod into the Gneuss Multi Rotation Extruder type MRS 90. This ran with a throughput rate of 300 kg/h. The material was filtered using a Gneuss fully automatic self cleaning screen changer type RSFgenius 90.The viscosity of the PET melt was measured and controlled via the vacuum on the extruder from the Gneuss Online Viscometer type VIS. A 700 mm wide sheet die from EDI was used to make a 430 µm thick sheet. Davis Standard provided a 1.200 mm wide downstream sheet line specially for this pilot line application, consisting of a roller stack, roller track with edge trimmer and a capstan winder. The edge trim was granulated using a Herbold edge trim granulator and returned to the process.

"The low level of yellowness, the good surface quality and the ability to use the sheet without restrictions for food contact applications really impressed visitors” explained Dr. Carl-Jürgen Wefelmeier, manager or the processing technical facility at Gneuss. "The main advantage of our special extruder is quite clear: the processing of PET without pre-drying or any pre-treatment with a simple, conventional water ring vacuum pump to a high quality product”.

A direct recycling process for PET fibres was shown on another production scale line. Fibre waste was fed (without pre-treatment such as agglomeration etc.) via an NGR Cutter-Feeder combination directly into an MRS 110 extruder. This line operated with a throughput rate of 400 kg/h and was equipped with a Gneuss fully automatic self cleaning screen changer RSFgenius 150 with 30 µm filtration fineness and an underwater pelletising system from Econ.

Polyester Recycling Forum
After the demonstrations, Dr. Thiele invited the visitors to a "Get Together” in the elegant Kaiserpalais in Bad Oeynhausen. This was the perfect environment for the visitors to meet and exchange ideas prior to the Polyester Recycling Forum.

The Polyester Reycling Forum on October 5th offered a wealth of information on different aspects of PET recycling. From the material itself through the preparation stages of bottle flake and with practical reports such as on the processing of PET bottle flakes to fibres.

Dr. Martina Lehmann from MAKSC GmbH clearly emphasised how changes in the input material will affect recycling systems in future - for example PVC mixtures. She also pointed out which methods are necessary for material preparation and quality control are necessary in order to achieve and maintain the required production standard.

Harald Zang from Automatik Plastics Machinery GmbH explained the pelletising systems available for recycling processes. Energy savings through direct crystallisation were of particular interest.

Detlef Plotzitza from Bühler discussed the growth of PET plant capacities for bottle to bottle recycling systems and explained a bottle to bottle system for 150 tpd as an economically viable system for the near future. The individual elements, starting with the flake production and sorting through to the SSP are already all available with the required capacity.

Günther Klammer from MAS GmbH gave an overview of the co-rotating conical twin screw extruder technology from MAS and underlined how particularly suitable this system is for handling materials with a low bulk density, as is encountered with PET flakes.

Werner Herbold from Herbold Meckesheim GmbH gave an overview of the current state of the art technology for processing PET bottles to flake. In order to prevent the increasing quantity of PVC labels negatively affecting product quality, he recommended a special device developed by Herbold for removing the labels before the bottles are shredded.

The presentation by Dr. Stephan Gneuss from Gneuss Kunststofftechnik GmbH concentrated on the use of the new Multi-Rotations-System in the manufacture of PET flake for processing to food contact packaging material. Up to 100 % bottle flakes can be processed to FDA standards without pre-drying.

Sabine Schönfeld from Coperion covered the long history of the co-rotating twin screw extruder and its development for PET processing without pre-drying when this was demonstrated for the first time at the K 1992 exhibition. The increased performance of these machines in recent years impressed the listeners.

Gion-Pitschen Gross from Oerlikon Neumag explained the manufacture of staple fibres from bottle flakes in both single and double stage processes. Of particular interest was the fact that even demanding fibres such as self crimping bicomponent fibres can nowadays be manufactured from PET bottle flakes.

Peter Mayer from Se-So-Tec GmbH presented the latest developments in the field of sorting technology. Through the combination of various different sensor systems with high precision sorting and separating technologies, PET bottle flakes can at the end of the sorting and separating process be offered with a high level of purity with regard to colour, shape and material type. Preliminary separation can be dispensed with.

Edward Kosior from Nextek Ltd. pointed out problems in the optical recognition of black coloured plastics and explained a new process for the identification and separation of black coloured A-PET, C-PET and PP food containers using N-IR spectography.

Dr. Joachim Hans-Roland Voigt from Silon s.r.o. reported his impressive wealth of practical experience in processing PET bottle flakes to staple fibres from 100 % bottle flakes. He explained the advantages and disadvantages of compact spinning and 2 stage processes. Dr. Voigt showed that the production of special PET fibres in Europe can be successful under certain conditions.

Dr. Ulrich Thiele from Dr. Thiele Polyester Technology investigated the influence of raw material quality on the investment volume for equipment for PET recycling. His research shows that for the production of for example POY or high performance fibres it makes sense to integrate the process vertically so that the process integrates the purchase of the bottles through to the final product.

Reprints of the conference handouts can be obtained for a handling charge. Please send your request by email to: drthiele@polyester-recycling.com.