Starlinger's melt filter enables high recyclate content in PP woven bags

New backflush filter from Starlinger & Co. GmbH allows manufacturers of woven bags made of polypropylene tapes to use a proportion of recycled polypropylene of 50% and more in the tape extrusion process.

Especially when it comes to packaging made of tape fabric, which is characterized by its high strength properties, high-quality tapes are important requirement. The tear-resistant sacks are filled with up to 50 kg of contents – in the case of big bags, the fabric even has to sustain two to three tonnes of weight. When using recycled material, the Starlinger SPB filter ensures very good melt filtration for the high tape quality required.

In tape production, impurities and, in many cases, the range of different polymers in the recycled input material cause problems such as filter blockages or tape tears, which, in turn, reduce production efficiency.

Single-piston backflush filter from Starlinger for use of recycled polypropylene in tape production.

The SPB melt filter from Starlinger, on the other hand, achieves a high melt throughput with good cleaning capacity even in the case of more heavily contaminated input material. This way, a stable production process and high degree of efficiency are ensured.

Thanks to the hydraulic backflushing function of the filter, the respective filter screen is backflushed and thus cleaned when a defined degree of contamination is reached. The backflush cycles are relatively short due to the high pressure build-up in the filter, and the extrusion process is not interrupted – an important criterion that saves material and time.

Depending on the degree of contamination of the melt, the filter can achieve throughput rates of up to 720 kg/hour and allows for 50% and more of recyclate in tape production.

According to Hermann Adrigan, Head of Sales at Starlinger, “For optimum recyclate quality, our division Starlinger recycling technology offers recycling plants that are tailored to the specific needs of bag manufacturers.”

“In principle, we at Starlinger combine the know-how and technology for circular packaging under one roof: From the manufacturing process and the packaging recycling process to reusing the recyclate for the same product. With our equipment, it is a lot easier for packaging manufacturers to use recycled material in the extrusion process,” Hermann Adrigan added.