Antioxidant 168 CAS 31570-04-4

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CAS：31570-04-4

Molecular Formula:C42H63O3P

Molecular Weight:646.94

EINECS:250-709-6

Antioxidant 168 is an excellent phosphite ester antioxidant, the appearance of white powder, easily soluble in benzene, chloroform, cyclohexane and other organic solvents, slightly soluble in ethanol, acetone, insoluble in water, alcohol and other polar solvents, slightly soluble in esters. Low toxicity, low volatility, high thermal stability, excellent hydrolysis resistance, can effectively decompose the hydroperoxide produced in the process of hot processing polymeric materials. It has good synergistic effect when combined with hindered amine antioxidants 1010 and 1076, and can improve the stability of during hot processing of polymeric materials. More than a dozen kinds of preparations have been mixed with phenolic antioxidants, which are widely used in polyolefin (such as polyethylene, polypropylene) and olefin copolymers, polyamides, polycarbonate, PS resin, PVC, engineering plastics, rubber and petroleum products, ABS resin and other polymer materials.

Item	Specification
Appearance	White powder
Light transmittance	425nm ≥98%; 450nm ≥98%
Volatile matter	≤0.3%
Ash content	≤0.1%
Melting point	183-187 ℃

Antioxidant 168 is a phosphite ester antioxidant mainly used as a processing stabilizer in polymer manufacturing. It efficiently decomposes hydroperoxides generated during high-temperature processing and helps maintain polymer performance, color, and molecular stability.

1. Polyolefin Manufacturing

Antioxidant 168 is extensively applied in polyethylene (PE), polypropylene (PP), and olefin copolymer production. During extrusion and injection molding, it helps reduce thermal oxidation, melt degradation, and yellowing.

For improved long-term thermal protection, Antioxidant 168 is frequently blended with Antioxidant 1010 in polyolefin stabilization systems.

2. Engineering Plastics

The product is suitable for ABS, polycarbonate, nylon, PS resin, and engineering plastic compounds requiring high thermal processing stability and low volatility.

3. PVC & Rubber Processing

In PVC and rubber formulations, Antioxidant 168 improves heat resistance during compounding and processing while helping maintain physical properties under long-term heat exposure.

It can also be used with sulfur-containing auxiliary antioxidants such as Dilauryl Thiodipropionate (DLTDP) for enhanced oxidation resistance in polymer systems.

4. Recycled Polymer Applications

Antioxidant 168 is widely used in recycled plastics and reprocessing systems because it minimizes polymer chain degradation caused by repeated thermal cycles.

5. Masterbatch & Compound Production

The product is also suitable for color masterbatch, filler masterbatch, and industrial compounding applications requiring stable processing performance and excellent compatibility with polymer matrices.

More polymer additives are available on the Unisunchem Home Page and the Uniaox® Antioxidant Category.

Excellent hydroperoxide decomposition capability during polymer processing
Outstanding thermal processing stabilization performance
Low volatility and excellent hydrolysis resistance
Helps minimize discoloration and polymer degradation
Suitable for PE, PP, ABS, PVC, polycarbonate, and engineering plastics
Effective synergistic performance with hindered phenolic antioxidants such as Antioxidant 1010
Excellent compatibility in recycling and compounding applications
Stable supply and technical support from Unisunchem

25kg/drum or according to customer requirements.The product is stable and has no special storage requirements, but should be protected from moisture and heat.

Q1: What is Antioxidant 168 mainly used for?

Antioxidant 168 is mainly used as a phosphite processing stabilizer in polyolefins, engineering plastics, PVC, rubber, and recycled polymer systems.

Q2: Why is Antioxidant 168 important in polypropylene processing?

It helps decompose hydroperoxides generated during high-temperature processing, reducing polymer degradation, viscosity loss, and yellowing in PP production.

Q3: Can Antioxidant 168 be combined with phenolic antioxidants?

Yes. Antioxidant 168 is commonly formulated with Antioxidant 1010 and antioxidant 1076 for improved long-term thermal stabilization.

Q4: Is Antioxidant 168 suitable for recycled plastics?

Yes. It is widely used in recycled polymer processing because it improves melt stability and reduces thermal degradation during repeated extrusion cycles.