High performance antioxidants for polyamides
Polyamides are commonly used in electrical / electronic & automotive under hood (bonnet) molding applications requiring long term heat stabilization. Copper iodide is still widely used as a stabilizer in these applications but has the disadvantage of giving dark coloration, causing tool corrosion & copper plate out. Addivant™ NAUGARD® 445 & FLEXAMINE® arylamine antioxidants are able to efficiently replace these copper systems without corrosion issues.
For polyamide (PA6 & PA66) white goods, & in sport & leisure applications, combinations of Addivant™ antioxidants are recommended. LOWINOX® HD98, phenolic, primary antioxidant, is particularly compatible with polyamide structures as is ULTRANOX® 626, a high activity, phosphite, secondary antioxidant.
For PA11 or PA12, combinations of LOWINOX® GP-45 or LOWINOX® 44B25, phenolic, primary antioxidants & ALKANOX ® 240, a phosphite, secondary antioxidant are recommended.
Polyamide fibers & tire cords demand a stabilization system that is able to efficiently protect the polymer at the very high temperatures reached during the spinning operation. These are commonly stabilized using Addivant™ LOWINOX® 44B25 or LOWINOX® GP45 phenolic antioxidants. Addivant™ LOWINOX® 44B25 is also used to protect , against degradation , spin finishes applied to hot fibers at the spinneret exit.
Antioxidants such as Addivant™ LOWINOX® HD98 stabilizer are sometimes added during polymerization, in caprolactam solutions (PA6) or in water dispersions (PA66).
High performance UV stabilizers for polyamides
Polyamides are also used for pigmented /filled outdoor applications in hot climates, where long-term UV stabilization is required. Low volatility light stabilizers such as Addivant™ LOWILITE® 28 or LOWILITE® 234 UV absorbers combined with LOWILITE® 62 or LOWILITE® 94 HALS are often added to the polyamide to provide effective stabilization for such applications..
For fiber grades, Addivant™ LOWILITE® 19 UV stabilizer is recommended to minimize gas fading discoloration.
Polymer modifiers for polyamides
ROYALTUF® 485 polymer modifier semi-crystalline EPDM grafted with 5% maleic anhydride effectively improves the impact properties of polyamides. In applications requiring excellent low temperature impact properties , Addivant™’s ROYALTUF® 498 polymer modifier amorphous EPDM grafted with 1% maleic anhydride is recommended.