Antioxidation and Heat Aging Stabilization


SI Group offers a selection of products that are specifically designed to improve the stability, performance, and impact resistance of nylon and polyamide polymers in a wide array of applications.
Click your desired functionality to learn more:


Copper iodide is a commonly used stabilizer in nylon and polyamide plastics, but it typically causes copper plate out, corrosion, dark colorations in addition to its environmental concerns. SI Group offers a broad range of antioxidants and stabilizers that are designed to meet your specific application needs:
High demanding heat stabilization applications:
Polyamide (PA6 & PA66) white goods:
A combination of LOWINOX™ HD98 and ULTRANOX™ 626 is recommended. LOWINOX™ HD98 is a primary phenolic antioxidant that offers excellent compatibility with polyamide compounds, and ULTRANOX™ 626 is a high activity phosphite secondary antioxidant that optimizes the color and heat stability for extended protection.
Polyamide PA11 or PA12:
A combination of LOWINOX™ GP-45 or LOWINOX™ 44B25, phenolic primary antioxidants, and ALKANOX™ 240, a phosphite secondary antioxidant is recommended for PA 11 and 12 polyamide polymers.
Polyamide fibers & tire cords:
LOWINOX™ 44B25 or LOWINOX™ GP-45 phenolic antioxidants are recommended as they offer the required protection at the high-temperature of the spinning operations. LOWINOX™ 44B25 is also used to protect the spin finishes from degradation when applied to the hot fibers.



Impact Resistance and Modification
ROYALTUF™ is a family of chemically modified EPDM rubber that is engineered to improve the impact resistance of Nylon 6 and 6,6 compounds. ROYALTUF™ products provide improved toughness, strength and impact modification properties in temperature-critical nylon applications. It offers:
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15X higher impact strength
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Outstanding low-temperature impact performance
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Significantly improved toughness and dimensional stability
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Reduce waste and improve recycling performance
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Effective at improving the impact performance of recycled resins
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Generally added to nylon compounds at 5% to 20% by weight, directly at the compounding extruder
The graph shows the impact improvement using ROYALTUF 485 in Nylon 6,6 and in Nylon 6,6 alloys with polypropylene (PP). It is also effective at improving impact performance in recycled resin and other thermplastic compounds.


Coupling and Compatibilization
POLYBOND™ coupling agents are used as compatibilizers in nylon and polypropylene blends and alloys. The coupling agents reduce the domain size of the two polymers, resulting in increased tensile strength, improved flexural properties and impact resistance.
The scanning electron micrographs show the morphology of two PA/PP alloys with and without the addition of 2.5% POLYBOND™ compatibilizer. The improved dispersion and reduced phase sizes provide superior performance and enhanced strength to the alloy parts.


UV Stabilization and Resistance
Polyamide polymers and alloys are commonly used in outdoor applications. They are typically pigmented and exposed to hot climates which makes them require long-term UV and light stabilization. Light and UV stabilizers with low volatility are highly recommended for an extended protection in such applications.
A combination of LOWILITE™ 28 UV absorber, and LOWILITE™ 62 HALS or LOWILITE™ 94 HALS provide effective stabilization in a wide array of polyamide outdoor applications.

