Antioxidant PQ: A highly effective auxiliary solution focused on polymer processing and color stability.

During the production and processing of polymer materials, thermal oxidative degradation and yellowing are common challenges affecting product performance and appearance quality. Antioxidant PQ (chemical name: Tetra(2,4-di-tert-butylphenol) 4,4'-biphenyldiphosphate), as a mature phosphorus-containing auxiliary antioxidant, is precisely designed as an efficient solution to address these challenges. Through its scientifically engineered mechanism of action, it reliably enhances processing stability and preserves product color across diverse applications including polyolefins, engineering plastics, elastomers, and adhesives.

Core Functionality: Clear and Focused

Antioxidant PQ's core role manifests in two complementary aspects:

Providing Excellent Processing Thermal Stability: During high-temperature processing like extrusion or injection molding of polymers such as plastics and rubber, heat and mechanical shear induce material oxidation. This leads to unstable melt viscosity and molecular chain breakage, ultimately compromising the mechanical properties of the final product. Antioxidant PQ effectively decomposes hydrogen peroxides generated during processing, interrupting oxidative chain reactions. This helps maintain stable rheological properties of polymers within the processing window, ensuring smooth production and fundamental product quality.

Delivering Efficient Color Stability: Many polymer products, especially light-colored or transparent items, are prone to irreversible yellowing during processing or subsequent use. This may stem from oxidation of the polymer matrix itself or from conversion products of certain additives (such as primary antioxidants). By inhibiting hydrogen peroxide generation, Antioxidant PQ reduces the formation of chromophores at the source, significantly improving product appearance and long-term color retention.

Mode of Action: Synergistic Enhancement, Not Replacement

It is important to note that antioxidant PQ is typically used as a complementary component alongside primary antioxidants (such as hindered phenols). Primary antioxidants primarily capture free radicals, while antioxidant PQ focuses on decomposing hydrogen peroxides. Their combination produces a synergistic effect where “1+1>2,” forming a more comprehensive antioxidant protection system. This blending approach has proven effective in balancing short-term processing stability with long-term thermal-oxidative aging stability.

Primary Application Areas

With its excellent compatibility and high efficiency, Antioxidant PQ is suitable for various synthetic material systems requiring processing stability and appearance control:

Polyolefins: Widely used in injection molding, fiber, and film products for polypropylene (PP) and polyethylene (PE).

Engineering Plastics: Suitable for polyamide (PA), polycarbonate (PC), polyester (e.g., PBT), etc., helping maintain performance and color during high-temperature processing.

Elastomers and Adhesives: Used to improve stability in certain synthetic rubber and adhesive systems during preparation and use.

High-Performance Coatings: Particularly suitable for powder coatings, coil coatings, and other applications requiring high-temperature curing with stringent color requirements.

Product and Usage Guidelines

Antioxidant PQ typically appears as a white or off-white powder. Its efficacy depends on proper usage and storage:

Typical Dosage: Generally recommended at 0.05%-0.3% of total polymer weight. Specific dosage should be determined experimentally based on the resin system and formulation.

Critical Storage Requirements: This product exhibits hygroscopic properties. To ensure optimal performance, store in a cool, dry location with packaging tightly sealed to prevent moisture absorption, which can cause hydrolysis of active components and performance degradation.

Summary

In summary, Antioxidant PQ is a market-proven, functionally defined polymer auxiliary stabilizer. It does not seek to replace other additives but focuses on providing robust processing protection and color preservation through its unique ability to decompose hydrogen peroxides within complex material formulations and under demanding processing conditions. For materials engineers seeking to enhance product quality stability and appearance consistency, it represents a highly effective auxiliary option worthy of consideration and testing.