Description

Bis(2,4-Di-tert-Butylphenyl) [1,1-Biphenyl]-4-Ylphosphonite is a high-performance organophosphorus compound widely recognized as a highly effective secondary antioxidant and process stabilizer. Its primary value lies in its ability to prevent polymer degradation during high-temperature processing, thereby extending material lifespan and maintaining critical physical properties. This product is essential for manufacturers in the plastics, synthetic fiber, and elastomer industries who require reliable protection against thermal and oxidative stress for their polymer formulations.

Application

• Polymer Stabilization: Acts as a secondary antioxidant (phosphite) in polyolefins (PP, PE), polyesters, and engineering plastics to prevent thermal degradation during extrusion, injection molding, and other melt-processing operations.
• Color and Melt Flow Retention: Effectively inhibits the formation of colored oxidation products and helps maintain consistent melt flow index (MFI) in polymers subjected to high-temperature processing.
• Synergistic Stabilizer Systems: Used in combination with primary phenolic antioxidants to create synergistic stabilization packages, offering superior long-term thermal stability for demanding applications.
• Elastomer and Rubber Protection: Provides processing stability and heat aging resistance in synthetic rubbers and thermoplastic elastomers (TPEs).
• Adhesive and Sealant Formulations: Enhances the thermal-oxidative stability of hot-melt adhesives and sealants, preventing gelation and viscosity drift.
• Fiber Production: Protects synthetic fibers like polypropylene and polyester from molecular weight breakdown and yellowing during high-speed spinning and drawing processes.

Basic Information

Product Name	Bis(2,4-Di-tert-Butylphenyl) [1,1-Biphenyl]-4-Ylphosphonite
CAS No.	91362-37-7
Molecular Formula	C44H57O2P
Molecular Weight	648.89 g/mol
Synonyms	Bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite; Pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) phosphite stabilizer (related class); Irgafos 126; Hostanox PAR 24; Phosphite antioxidant 626; 2,4-Bis(1,1-dimethylethyl)phenyl phosphite (3:1) with pentaerythritol; Tris(2,4-di-tert-butylphenyl) phosphite (common confusion, note difference); Antioxidant 626
EINECS	Contact for details

Quality Control

Our production of Bis(2,4-Di-tert-Butylphenyl) [1,1-Biphenyl]-4-Ylphosphonite adheres to stringent quality management protocols to ensure batch-to-batch consistency and performance reliability. Each lot undergoes rigorous analytical testing, including assay by HPLC, determination of hydrolyzable chlorine, and measurement of key physical properties. Certificates of Analysis (COA) documenting full compliance with our internal specifications are available for every shipment upon request.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry, and well-ventilated area at room temperature (15-25°C). This material is hygroscopic (moisture-sensitive) and easily oxidized; therefore, containers must be kept tightly sealed under an inert atmosphere (e.g., nitrogen) after opening to prevent moisture uptake and oxidation, which can compromise product efficacy.

Specification

Item	Specification
Appearance	White to off-white crystalline powder
Identification (IR)	Conforms to reference spectrum
Assay (HPLC)	≥ 98.0 %
Melting Point	185 - 195 °C
Hydrolyzable Chlorine	≤ 50 ppm
Volatile Matter	≤ 0.5 %
Solution Color (APHA)	≤ 50

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.