WESTCO™ AO-168 Tris (2,4-di-tert-butylphenyl) phosphite CAS# 31570-04-4

WESTCO™ AO-168 is a versatile secondary antioxidant, giving excellent protection to melt flow & color during thermal processing.   It can be used in a variety of polymers, including elastomers, polyolefins, polycarbonates, polyesters and styrenics.  It is normally used with hindered phenols, like WESTCO™ AO-1010 or WESTCO™ AO-1076 for synergistic performance.  It may also be used with UV absorbers or hindered light stabilizers for optimal performance.  WESTCO™ AO-168 has excellent resistance to extraction during submersion in water.  It acts to decompose and scavenge hydroperoxide free radicals during polymer processing.

Packaging : 25kg cardboard box with plastic bag liner.


Appearance: White powder
*Assay (HPLC)

99% Min.

*Melting Point

181 – 187 °C


0.3% Max.

*Light Transmitability

425 nm 98% Min. 500 nm 98% Min.

*2, 4 Tert butyl phenol

0.2% Max.

SG @ 72 °F (22.2 C°)


*Actual tech data / technical data values reported on Certificate of Analysis.

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      • Akron, OH 44305

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