By Ron Shinn
Struktol has two additives aimed at reducing odor and improving processing of plastics with high recycled content.
The additives were originally developed for another application but have become increasingly popular for use with recycled resin, according to Mike Mikolay, a Senior Fellow at Struktol.
The two products are labeled RP 17, primarily an odor mask to improve the final product’s scent, and RP 53, an odor neutralizer. They work with PP and PE resins.
RP 17 can be added during compounding, extrusion or molding to eliminate or mask undesirable odors caused by post-industrial or post-consumer recyclate or other ingredients added during compounding. It is especially useful in automotive applications where higher process temperatures often make odors more noticeable.
At low dosages, Struktol said it tends to neutralize odor, while at higher dosages it will impart a fresh “clean” odor. Struktol recommends a starting dose of 0.5 percent. Typical doses are 1 percent to 3 percent.
RP 17 is white pastille with a dropping point of 221 degrees Fahrenheit to 248 degrees Fahrenheit and specific gravity of 0.94. A pastille is similar to a resin pellet but more spherical. The company said it offers consistent melt behavior and seamless integration into processing lines.
It is available in 55-pound bags and can be stored for at least two years.
RP 53, similar to RP 17, can be added during compounding, extrusion or injection molding to mask odors and is also suitable for automotive applications where high temperatures increase odors.
It targets mercaptans, amines and phosphites, and has VOC absorption properties.
Recommended starting dosage is 0.5 percent but more or less may be used for desired results, according to Struktol.
It is an off-white pastille with a dropping point of 212 degrees Fahrenheit to 266 degrees Fahrenheit and specific gravity of 1.07. It is also sold in 55-pound bags and can be stored for at least two years.
“Critically, these additives support sustainability initiatives by enabling the use of 100 percent recycled-content compounds without compromising the end product’s sensory or physical quality,” Struktol said in a news release.
RP 17 also functions as a process lubricant and mold release agent, according to Struktol. This improves processability, reduces plate-out, eases part release and minimizes cleaning requirements.
The odor masking and odor neutralizing elements of the additives use a Struktol lubricant as a carrier, making each of them a dual-function additive, according to Mikolay.
Struktol also said that both additives improve dispersion of fillers and recycled content, reduce processing time and improve the surface finish of end products.
Because small amounts of RP 17 or RP 53 are typically used, they do not change the final product’s recyclability. They typically do not wear off very quickly because plastic has low permeability. “Whatever is inside tends to stay inside longer,” Mikolay said.
Both products can be added anywhere along the processing chain, but compounders tend to be the biggest users of odor-elimination additives.
