Plastic Sorting: Distinguishing between HDPE and LDPE

By launching two applications for its mobile NIR spectroscopy solution, trinamiX (a subsidiary of BASF SE) is improving on-the-spot sorting of the sought-after plastic.

Due to rising prices for polyethylene (PE), the production of single-grade PE recyclates has become increasingly attractive: This material is the most widely produced plastic in the world and the most popular thermoplastic for foils and packaging. Depending on its density, PE can be divided into HDPE (high-density polyethylene) and LDPE (low-density polyethylene). While the similar characteristics of HDPE and LDPE lead to overlaps in their respective applications, differences in their mechanical properties have an impact on their processing and the subsequent recycling process. In the context of recycling, a separation by type has a favorable effect on the quality of the recyclate.

Additionally, trinamiX’s solution now provides also insights when it comes to the recovery of mixed plastics made of PE and PP. By determining the percentage ratio in PE/PP mixed plastics, recyclers can sort incoming commodity streams with greater precision. “This way, the different specifications and quality requirements of the recyclates can be attained more accurately,” the Germany-based company, which was founded in 2015, assured.

Since the introduction of the plastic sorting application last year, the solution has supported users with the rapid identification of common plastics, including the polyolefins PE and PP. Additionally, there is an application enabling the quick differentiation of the engineering plastics PA6 and PA66.

As reported, trinamiX’s solution combines robust hardware with intelligent data analysis and a mobile app. NIR spectroscopy is a proven technology that trinamiX has integrated into a portable format for on-site analysis.

“In doing so, trinamiX relies on cloud-based data processing, which ensures continuous development of the solution – there is no need to replace hardware,” the company belonging to the BASF Group underlined. “This allows trinamiX to continuously develop new applications and react flexibly to new challenges in the field of plastic sorting – while working closely together with customers as in the case of its new PA6/PA66 application.”

(Published in GLOBAL RECYCLING Magazine 2/2021, Page 49, Photo: trinamiX GmbH)