Versatile phosphite stabilizer that improves color, processing stability, and end-use of a variety of polymers; similar to WESTON™ 398 but with food contact approvals.
Product Overview
WESTON™ 399 is a phosphite antioxidant that improves color and processing stability during recovery, drying, compounding, processing and end use. It has low nonylphenol content, is approved for food contact, and synergizes when used along side hindered phenolic antioxidants.
Product Specifications
Appearance: Clear liquid
Specific Gravity @ 25 °C: 0.980-0.992
Color (Pt - Co): 75 max
Flash Point (Closed Cup): 196 °C
Density @ 25 °C: 0.98 g/mL
Vapor Pressure @ 6 mm Hg: 245 °C
Molecular Weight: 688 g/mol
Viscosity @ 60 °C: 250 cps
Acid Number: 0.25 mg KOH/g max
Refractive Index @ 25 °C: 1.5250-1.5280
Free Nonylphenol Content: 4.0% max
Phosphorus Content: 4.1-4.5%
Chlorine Content: <25 ppm
Free Phenol Content: <50 ppm
Specific Heat: 0.4 mcal/mg°C
Thermal Conductivity: 0.0003 gcal/sec(cm²)(°C/cm)
Auto-ignition Temperature: 439 °C

Primary Chemistry: Trisnonylphenyl Phosphite
Features & Benefits
Low color
Low nonylphenol content
Food contact approvals
Synergizes when used along side phenolic antioxidants
Problems Solved
FDA clearance of liquid phosphite antioxidants for use in food contact applications
Synergy issues of liquid phosphite antioxidants with hindered phenolic antioxidants
Regulatory restrictions on the level of nonylphenols in a formulation
High density polyethylene, linear low density polyethylene