Kraton - a world-leading specialty polymer and biobased chemical solutions supplier has developed new innovative solutions that enable improved quality and a higher recycling rate of polyolefins.

Quality problems with rHDPE Recycled

HDPE is typically contaminated with some PP and Norner has seen that this has caused a reduction in the properties of rHDPE. Throughout multiple projects, Norner has documented strong variations in the quality of such recycled HDPE (rHDPE), compared to virgin HDPE. Several rHDPE suppliers have such quality issues specifically for the bottle market.

Given Norner’s experience with EBM and PCR testing, Kraton approached Norner to perform multiple tests to evaluate rHDPE performance enhancement enabled by Kraton’s CirKular+™ additives. A new fully electric EBM line at Norner with 3 extruders and flexible capability for materials and blends, which has proven to be a very good tool to evaluate the use of recycled material for end-uses within food, household chemicals, and personal care would be used in the trials.

The performance testing results achieved by Norner further prove the value of Kraton CirKular+™ additives in solving the discussed challenges for the packaging industry. We value the pleasant collaboration with Norner and their expertise in the EBM and PCR testing. - Dr. Lennaert Klerk, Regional Technical Manager Europe at Kraton Polymers

Kraton test program

Recycled HDPE was used for these tests with 5 or 10 % contamination of PP. The contaminated HDPE was processed while adding CirKular+™ additives in levels from 1-5 % by dry-blending the material and directly feeding it to the EBM machine. We documented the possible enhancement by drop testing. The results show impressive numbers for the modification of the rHDPE blend with CirKular+™. It is important to note that it is typically difficult to achieve homogeneity for an HDPE contaminated with PP, and often large variations in drop performance are observed. The use of Kraton’s CirKular+™ allows for bringing rHDPE drop performance back to the level of the original virgin HDPE while reducing the typically observed variability in the drop performance.

Top load is another important property for bottles. Contamination of the stiffer PP can increase the top load. Modification with up to 5 % CirKular+™ has shown the ability to achieve the top load of a virgin HDPE level. The trials also showed that the desired aesthetics can be achieved for the bottles containing CirKular™ in a conventional EBM machine. For further information contact Norner AS or Kraton Corporation.

The article is written by Morten Augestad, Director BU Consumables at Norner. Published: March 7, 2024.