ADDITIVES | PROCESSING AIDS
Right: Dow’s Paraloid and Surecell
additives can ease produc- tion of PVC foam structures
portion of PVC foam is produced as thick sheet that is cut into boards and used to replace wood in non- load bearing exterior construction applications.
Upcycling polyolefins Cevo-process B-3690 from Völpker is a dispersion additive intended for post-consumer HDPE/LDPE recycling operations. This type of waste often contains unwanted polymer particles and mineral contaminants (among others) that disrupt produc- tion and reduce the quality of the recyclate. “Their proper dispersion as well as the dispersion of new fillers such as carbon black is mandatory in order to produce adequate recycling qualities for, for example, injection moulding,” says the company. Carbon black at a level of 2% is very well dispersed in virgin HDPE when 0.5 % Cevo-process B-3690 is also added, the company says. Grayscale microscopic images (Figure 4) of manufactured foils show that the number of carbon black agglomerates can be significantly reduced using the additive. Carbon black (2%) and insoluble contamination particles are also highly dispersed in a typical LDPE/HDPE post-consumer recycling system when additivated with 0.5% Cevo-process B-3690, Völpker says. Struktol recently introduced its VMO line of masterbatches for modifying the melt flow of recycled PP. The masterbatches also include an odour neutraliser. “This VMO series can be very useful for manufacturers that want to reduce the amount of virgin or recycled PP of differing MFIs they keep on hand,” says the company. “Having one type of PP resin of low MFI would allow for any number of higher MFI possibilities.” VMO series products have been designed to allow for the presence of PE, in some cases upwards of 35%. Grades in the series have varying levels of
activity. In some cases low activity is needed, says Struktol, as this allows for a higher percentage dosing which would be useful in cases where
dosing very small quantities could be problematic. Riverdale Global’s +Restore Additive is being used to improve properties of PP and HDPE PCR. Tests using regrind have shown that virgin-like properties can be obtained with 100% recycled PP or HDPE and a low level of the liquid additive (typically 0.1 to 0.5%). “Because the additive has an affinity for the base polymer, it acts as a lubricant, enhancing melt flow,” says Jared Arbeter, Technical Sales Manager at the company. “In addition, the +Restore molecule has a functional group that readily reacts with pigments, fibres, or fillers in the resin, while a different segment of the same molecule is designed to couple with the polymer; as a result, it forms a strong bond between resin and filler without compromising flexibility,” e says. Britec Solutions has developed BTec REA360
Regrind Enhancing Additive, which it says improves physical properties, reduces odour, and enhances processing performance of regrind and recycled resins. The additive is available in liquid and pellet forms. The company says that addition rates of 0.1 to 0.5% are sufficient to return physical properties of regrind and recycled materials to levels similar to that of virgin grades in both PE and PP.
Figure 4: Micrographs show the impact of addition of CEVO-process B-3690 on dispersion of 2% carbon black agglomerates in HDPE. The left image contains no additive; the right image an addition of 0.5%. Source: Völpker Spezialprodukte
68 COMPOUNDING WORLD | April 2021
CLICK ON THE LINKS FOR MORE INFORMATION: �
www.voelpker.com �
www.croda.com �
www.klkoleo.com �
www.avient.com �
www.addisperse.com (AFI Global) �
www.viscospeed.com �
www.dow.com �
www.struktol.com �
www.riverdaleglobal.com �
www.britecsolutions.com
Jennifer Markarian contributed to this article
www.compoundingworld.com
IMAGE: DOW
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