SPE Thermoforming Quarterly - SPE Thermoforming Division

Thermoforming Quarterly is a journal published quarterly by the Thermoforming Division of the Society of Plastics Engineers. The magazine is a great way to keep up with industry trends and developments. SPE Thermoforming Division members receive the magazine by mail four times a year. Non-members can access old issues here via PDF file. If you are not an SPE member this is a great reason to join! Become a member today to start receiving this valuable information in your mailbox.

We welcome objective, technical and related articles that provide valuable information to our community of thermoformers, toolmakers, material suppliers and OEMs. Articles are typically 1500-2000 words. We recommend viewing past articles for further guidance. All submissions should be in MS Word, 12-pt Times New Roman.

Artwork, illustrations, photos and graphics should be 300 dpi. We prefer .eps .jpeg and .pdf files

Deadlines for copy and artwork – 1st Quarter: February 15; 2nd Quarter: May 15; 3rd Quarter: August 1; 4th Quarter: November 15

All submissions can be sent to Conor Carlin, Editor, at cpcarlin@gmail.com

Thermoforming Quarterly Sponsorship Sales Contact: Lesley Kyle, +1 914-671-9524 or lesley@openmindworks.com

Third Quarter 2019

Thermoforming and In-situ Crystallization of Kepstan ® PEKK
By Roderick Reber III, Arkema, King of Prussia, PA

Polyaryletherketones (PAEK) are a family of ultra-high performance semicrystalline thermoplastic materials known for their extreme strength, chemical resistance, low flammability, and high use temperatures. The PAEK family includes PEK, PEEK, PEKK, PEEKK and PEKEKK among others. In their semicrystalline state PAEKs have among the best chemical resistance and Heat deflection temperatures (HDT) of as high as 240°C. However, the fast crystallization rate of most PAEKs makes them difficult or impossible to thermoform, especially in applications requiring thick gauge or deep draw ratios.

By using a PEKK copolymer with the optimum T/I ratio, it is possible to extrude an amorphous sheet that will crystalize slowly enough that it can be formed, but quickly enough that it can be crystalized on a heated mold within a reasonable cycle time. This In-process crystallization is a common practice for many thin gauge materials. For example PET is routinely thermoformed and crystalized during the forming process. The tunable crystallization rate of PEKK opens a new window to utilize the extreme performance of a semicrystalline PAEK in a thermoforming process.

Upcycling of Mixed APET Bottle Flakes into Thermally Stable rCPET Food Trays
By Sven Engelmann, Illig Maschinenbau GmbH & Co. KG (Heilbronn, Germany), Dr. Carl-Jurgen Wefelmeier, Gneuss Kunststofftechnik GmbH (Bad Oeynhausen, Germany), and Daniel Ganz, Sukano AG (Schindellegi, Switzerland)

Enhancing mixed bottle flakes by turning them into extrudable recycled crystalline polyethylene terephthalate (rCPET) was the goal of a joint development project looking to close the gap in the PET recycling system. By successfully producing a sheet made from recycled material suitable for high-quality applications such as thermoformed food trays, Gneuss, Sukano and Illig have demonstrated that this approach is indeed possible.

The recycling of bottle flakes derived from PET bottle collection systems as implemented and practiced in Germany, Austria and Switzerland, for example, has so far focused mainly on transparent and monochrome PET flakes. These can be recycled relatively easily into transparent food packaging. However, multicolored PET flakes (Title figure) are suitable only for inferior applications, because they cannot be re-pelletized and extruded as reproducible homogenous PET due to their different colors. As a result, in the first quarter of 2019 in Germany, for example, multicolored PET flakes had a market value (500 to 700 EUR/t), roughly only half the value of transparent PET pellets made from virgin material (1100 EUR/t), or recycled transparent PET pellets (1300 EUR/t).

For the production of trays, a multi-dimensional radiant heater is required. This is necessary because the crystallization of PET sheet can only be controlled by precision zonal temperature control in both the lateral and longitudinal directions. The tool technology is also designed specifically for the PET process as a two-step forming tool with heated cavity walls (Tg < Ttool cavity wall < Ts) in the first forming tool and cooled cavity walls in the second tool (Ttool cavity wall < Tg), where Tg stands for glass transition temperature and Ts for crystallite melting temperature of PET. In the first stage, the tray is given its form, receiving thermal energy for sufficient crystallization through contact with the heated tool cavity walls. The tool opens and the preformed ductile trays are moved along by the material transport into the second cavity with cooled tool cavity walls. The tool closes and in the second forming step the plastic hardens under contact with the cooled tool cavity walls, maintaining its shape while the crystallization process is completed – the formed trays are now oven-safe. Full articles appears in print magazine mailed to members.

2019