ADDITIVES | MATERIALS
Test results from 100% virgin PP compared with 100% PP regrind and PP regrind containing 0.4% +Restore additive: (left) flexural modulus; (right) tensile strength at break
Source: Riverdale Global
an additive acting as a chain extender, which allows a compounder to achieve higher value applica- tions. In customer evaluations, the company says that it has been shown that modification with this chain extender can rid flow instabilities in recycled HDPE, which cause a rough surface appearance on extruded profiles. Riverdale Global has developed a new liquid additive that enables processors to get ‘virgin-like’ properties from 100% regrind. The company says that low levels of +Restore can improve properties of PP and HDPE post-consumer recyclate while enhancing flow and part consistency. Physical property tests were carried out with a moulder of packaging containers for improving the performance of plastics regrind based on post-consumer waste. The tests compared 100% virgin PP with 100%
PP regrind containing 0.4% +Restore additive. For flexural modulus regrind PP tested at 99% of virgin PP, while it was 89% for strain at yield. Regrind PP tested higher than virgin, at 106%, for strain at break, while for Izod impact strength regrind PP modified with +Restore additive tested at 16% less than that of virgin PP, compared with unmodified regrind at 49% less. “These test results and similarly encouraging
data for HDPE show that plastics processors can use the +Restore additive to meet sustainability goals by actually upcycling post-consumer waste, eliminating most, and in some cases all, of the property losses typically incurred in recycling,” says Jared Arbeter, Technical Sales Manager. Arbeter adds that +Restore also improves part consistency in comparison with untreated recycled material. As measured by standard deviation in a range of physical property tests, for example, HDPE regrind with 3% white concentrate exhibited 50% or more decreases in part variation when it con- tained 0.4% of the +Restore additive. Other benefits are also provided by the +Restore addi- tive. Because the additive has an affinity for the base polymer, it acts as a lubricant, enhancing melt
www.plasticsrecyclingworld.com
Linear chain- extension of a long-chain PA for extrusion and monofilament processing: chart shows a substantial improvement in melt strength using Nexamite from Nexam Chemical
Source: Nexam Chemical
flow. 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, he says. Riverdale Global says that +Restore additive can be used in all thermoplastic processes, alone or in a blend with its liquid colours. Typical usage rates are in the 0.1-0.5% range. Brüggemann has developed additives for the
recycling of polyamides that is of particular significance for the automotive industry. “Sustain- ability as a central target for the future drives OEMs to increasingly focus on recycling and to include sustainability as an important part of their identity,” says Klaus Bergmann, Business Unit Manager Polymer Additives. “Legislation and European directives will provide further incentives. Recycling of polyamide components is integral to automotive sustainability and is aided by the use of perfor- mance additives.”
Additives for polyamide recycling include Bruggolen TP-M1417 and Bruggolen M1251/1253, allowing for precise and reproducible adjustment of the relative viscosities of PA waste to the level of
March/April 2021 | PLASTICS RECYCLING WORLD 45
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