Classification of antioxidants and application of commonly used grades

Primary antioxidant

Studies have shown that the process of material degradation and aging is a free radical chain reaction. The material is heated and sheared to generate free radicals, and oxygen generates free radicals. The peroxide radicals further take away hydrogen atoms from the polymer backbone to form relatively stable polymer-based hydroperoxides. The cycle reciprocates, the chain grows, and the reaction gradually expands.

A hydrogen donor-based antioxidant that terminates a chain reaction by supplying a H atom and consuming a peroxidic radical, and is called a primary antioxidant (also referred to as a radical inhibitor). Typical primary antioxidants include the following two categories:

Aromatic amine antioxidants: A long history, amine antioxidants are almost derivatives of aromatic secondary amines, mainly diaryl secondary amines, p-phenylenediamines and ketone amines, aldehyde amines and the like. Most of them have good antioxidant performance, but are easy to produce color stains, mainly used in the rubber industry and polyurethane products.

Hindered Phenolic Antioxidants: One of the most widely used primary antioxidants. Antioxidant efficacy is generally weaker than amine antioxidants, but not polluting, mainly used in plastic and light colored rubber products. Many well-known products such as 1010 and 1076 fall into this category.

Commonly used grade: antioxidant 1010

Application range:

Polyolefin: PP Film, PP Molding, HEPE Pipe, PP/HDPE Tape/PE Wire&Cable, PE Molding, LDPE/EVA Film, LLDPE Film

Elastomer: EPDM

Polyurethane: PVC

Polyurethane: RIM, TPU

Engineering plastics: POM, PA, PBT/PET

Commonly used grade: antioxidant 168

Application range:

Polyolefin: PP Fibers, PP Films, PP Molding, PE Wire & Cable, LDPE/EVA Film, LLDPE Film, PP Pipe

Styrene: ABS, PC/ABS, IPS, GPPS

Elastomer: S-SBR, BR, EPDM, SBS/SRS

Engineering plastics: PA, PC, PBT/PET, PMMA

Thioether is another class of auxiliary antioxidants, typical products such as DLTDP and DSTDP.

Antioxidant with main and auxiliary functions at the same time

An antioxidant that reacts with both peroxy radicals and hydroperoxides. A typical example is hydroxylamine. These antioxidants are very efficient due to their dual function.

Commonly used grade: antioxidant 1076

Application range:

Polyolefin: PP Molding\PE Wire&Cable, LDPE/EVA Film, LLDPE Film

Styrene: ABS, PC/ABS, IPS, GPPS

Elastomer: S-SBR, BR, EPDM, SBS/SRS, TPE

Polyurethane: PVC

Polyurethane: Flexible Foam, RIM, TPU

Engineering plastics: PC, PMMA, UP, PVB

Auxiliary antioxidant

An antioxidant that can react with the hydroperoxide produced in the above chain reaction to decompose it into a stable product, thereby terminating the chain reaction, is called a secondary antioxidant. Mainly thiodipropionate and other thioesters and phosphites. They are mainly used in polyolefins and in combination with phenolic antioxidants to produce synergistic effects.

Phosphites are the most widely used auxiliary antioxidants. Typical products such as 168.168 are phosphite anti-resistances, mainly providing thermal processing stability; the main anti-co-anti-co-use can produce synergistic effects (simple The ratio is: 1+1> 2)

Metal passivator

The contact between the polymer and the heavy metal is degraded by the catalysis of heavy metal ions. For example, the core wire of the cable material is copper, which often causes copper damage. Therefore, a copper ion passivating agent needs to be added, and the metal passivating agent can greatly increase the polymer. Stability.

Synergistic effects can be produced by combining different types of antioxidants. That is, the total effect of the two stabilizers is higher than the sum of the effects of the two alone. The most representative is the combination of hindered phenols and phosphite antioxidants.