At K2022, SML  presented the results of its joint R&D activities with Sukano AG and Kiefel Packaging B.V. - a C-PET light cup that combines transparency and recyclability as well as suitability for thermoformed hot-filling or microwavable products. Further advantages include short cycle times during thermoforming and a high stiffness. The newly developed C-PET light can thus be a reasonable option for manufacturers looking for an economic and easy-to-recycle alternative to PP and PS.

Transparency for recyclability 
“Because easy recyclability is becoming increasingly important, we opted for a transparent C-PET solution at an early stage of our joint research and development work” says Max-Phillip Lutz, Product Manager at SML. Compared to coloured PET or PP and PS products, the recycling process of C-PET light is considerably easier.C-PET light products do not cause any problems in existing recycling streams and facilities of post-consumer or post-industrial PET materials.

Alternative to PS and PP 
In general, C-PET is temperature resistant up to 220°C. However, this is not necessary for many applications and limits the output in thermoforming. In contrast, C-PET light was developed to withstand a maximum temperature of 100°C. The new C-PET light enables the manufacturing of transparent thermoformed products for hot-fill applications up to 100°C at output rates comparable to those of conventional A-PET processes. Especially the shorter cycle times during thermoforming are an economic advantage compared to conventional C-PET.

Adjusting process technology 
All three project partners shared their specific expertise and their profound experience in their respective areas in order to improve every single step in all processes. The main technical challenges were to find the optimum dosage for the additives, to adjust the formulations and the process technology during film production, and to find the right parameters for the thermoforming process.

Key characteristics of C-PET light:

• Suitable for transparent applications
• Short cycle times and high output compared with C-PET
• High stiffness compared with PP
• Recyclable

Redlham, 17.10.2022