Responsive image


Versatile phosphite stabilizer that improves color, processing stability, and end-use of a variety of polymers; similar to WESTON® 399, but with a higher flash point.




Product Overview

WESTON® TNPP is a cost-effective 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): 207 °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: 0.05 mg KOH/g
Refractive Index @ 25 °C: 1.5250-1.5280
Free Nonylphenol Content: 3.0%
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
Synergizes when used along side phenolic antioxidants
Food contact approvals


High density polyethylene, linear low density polyethylene

Related Products

SI Group Phosphite Antioxidants

SI Group Phosphite Antioxidants are solid and liquid secondary antioxidants that work in a variety of systems.

Talk to an Expert

ChemPoint has experienced product specialists on staff to provide our customers support in finding the right solution for their project. Talk to us, we can help.

Call us: 425.372.9464

Ask a Question Get a Quote Request a Sample