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HDPE Bottles – Going for 100% circularity

13 December 2015

One of the known issues using recycled content in extrusion blow moulded bottles is the bottom seal integrity. This is the reason that often no more than 25% of recycled material can be used.

During our pre-marketing phase earlier this year we carried out several blow moulding trials at moulders, using 100% experimental HDPE based on post-consumer waste, which was externally produced and based on cold-washed flakes. These trials confirmed the bottom seal phenomenon, which most likely was caused by the presence of non-polyolefin contaminations.

An extensive investigation was started to find  the cause of this seal integrity issue as we are targeting 100% QCP™ PE bottles. With a small bench top blow moulding machine we tested several compositions to mitigate the bottom seal problem.

In November we produced our first  in-house QCP™ material which did not show any weak spots in the bottom seal.

To verify these results, we ran a full-fledged blow moulding trial at a major blow moulder on a 6-fold BM machine producing 1-liter oil cans. The bottles did not show bottom seal problems and production ran smoothly without any modifications of the process.

Drop tests (see movie) from 2.10 meter height using water-filled bottles confirmed the quality; all bottles survived the fall!.

The used drop height was already exceeding the required drop height for this bottle (1.20 meter) and even more abusive testing (e.g. multiple drops of the same bottle) did not lead to failures!

This proofs that QCP’s more intensive cleaning (including hot-wash) and sorting process makes the difference.

Interested to run your own blow moulding trials? Contact sales@qcpolymers.com for more information.

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