Description

Tetrakis-(2,4-Di-tert-Butylphenyl)-4,4'-Biphenylenediphosphonite is a high-performance organophosphonite antioxidant widely used as a secondary stabilizer in polymer processing. This compound is valued for its exceptional ability to decompose hydroperoxides, thereby preventing oxidative degradation and extending the service life of finished polymeric materials. It is a critical additive for manufacturers in the plastics, synthetic fiber, and specialty elastomer industries seeking to enhance product durability and color stability under thermal and oxidative stress.

Application

• Primary application as a secondary antioxidant (hydroperoxide decomposer) in polyolefins such as PP (polypropylene) and HDPE/LDPE (high/low-density polyethylene).
• Used in combination with primary phenolic antioxidants (e.g., Irganox 1010) in polymer stabilization systems for synergistic performance.
• Critical for color stabilization in engineering plastics and synthetic fibers, preventing yellowing during high-temperature processing.
• Employed in the production of adhesives, sealants, and elastomers to improve long-term aging resistance.
• Used as a processing stabilizer in food-contact compliant polymers where applicable regulations are met.
• Applied in wire and cable insulation compounds to protect against thermal-oxidative degradation.

Basic Information

Product Name	Tetrakis-(2,4-Di-tert-Butylphenyl)-4,4'-Biphenylenediphosphonite
CAS No.	153453-64-6
Molecular Formula	C68H92O4P2
Molecular Weight	1035.41 g/mol
Synonyms	P-EPQ; Bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite (common misnomer); 4,4'-Biphenylenediphosphonic acid tetrakis(2,4-bis(1,1-dimethylethyl)phenyl) ester; Irgafos P-EPQ; Phosphite P-EPQ; Antioxidant P-EPQ; Hostanox PAR 24; Tris(2,4-di-tert-butylphenyl) phosphite (related but distinct compound)
EINECS	Contact for details

Quality Control

Our Tetrakis-(2,4-Di-tert-Butylphenyl)-4,4'-Biphenylenediphosphonite is manufactured under a strict quality management system. Every batch undergoes rigorous analytical testing to ensure it meets the high-purity standards required for sensitive polymer applications. A comprehensive Certificate of Analysis (COA) detailing purity, identity, and key physical parameters is provided with each shipment to guarantee traceability and consistency.

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 degradation. Keep away from heat and incompatible materials.

Specification

Item	Specification
Appearance	White to off-white crystalline powder
Identification (IR)	Conforms to reference spectrum
Assay (HPLC)	≥ 98.0 %
Melting Point	75 - 95 °C
Volatile Matter	≤ 0.5 %
Solution Color (APHA)	≤ 50
Acidity (as H3PO4)	≤ 0.05 %

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