Tiangang® AO-B277

What it is

Tiangang® AO-B277 is a antioxidant. Antioxidants come in two roles. Primary antioxidants (hindered phenols) trap radicals and stop the chain; secondary antioxidants (phosphites) decompose hydroperoxides. Used together they cover both processing and service life. Product identifiers: chemical name Mixture of tris (2,4-di-tert-butylphenyl)phosphite and 1,3,5; CAS 31570-04-4.

Technical data

Chemical name	Mixture of tris (2,4-di-tert-butylphenyl)phosphite and 1,3,5-tris(4-tert-butyl)-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazinane-2,4,6-trione
CAS No.	This product is a blend of a thioester antioxidant and a high-efficiency phenolic antioxidant: 31570-04-4 and 040601-76-1
Chemical structure	Mw=699                                                                                         Mw=647
Main uses and properties	Tiangang® AO-B277 is a versatile high-efficiency blended antioxidant for polyolefins, engineering plastics and other polymer materials. It prevents thermo-oxidative ageing during processing and in long-term service, and extends the service life of the finished article. Tiangang® AO-B277 shows low blooming, hydrolysis resistance, resistance to discolouration and low carry-over, and effectively prevents the drop in melt index, discolouration and embrittlement caused by thermo-oxidative ageing. The product can be used together with Tiangang® light stabilisers to extend outdoor service life.

Where it is used, and at what loading

Polyolefins are the main field, followed by polyacetal, polyamide, polyester, PVC, polystyrene and elastomers. The higher the melt temperature and the longer the residence time, the more the system needs.

Figures above are typical industry ranges, not guaranteed values. The actual loading depends on wall thickness, design life and the other additives in the system, and should be established by a loading ladder on the real formulation.

Choosing between similar grades

Three things decide the choice for AO-B277: molecular weight and volatility, basicity, and compatibility with the other components in the system. A general-purpose antioxidant compound for polyolefins and engineering plastics, for lines that prefer one product over several singles.

Frequently asked questions

Do primary and secondary antioxidants have to be used together?

In most cases yes. The primary handles radicals, the secondary handles hydroperoxides; using only one leaves the other degradation path open. Blends such as B215, B225 and B277 pre-mix the two, which removes weighing error at the line.

Why does low initial colour matter?

Some phenolic antioxidants form quinoid structures during processing and yellow the part. Fibre, film and light-coloured articles are most sensitive. Low-colour grades suppress that side reaction at the source.

Can antioxidants and light stabilizers interfere?

Yes, mainly through acid-base conflict. Acidic components (some phosphites, halogenated flame retardants) deactivate highly basic HALS. We look at both sides of the balance and switch to a low-basicity HALS where needed.

The figures and guidance above follow Tiangang's published technical material and common industry practice. For a specific formulation, refer to the batch COA and the technical agreement between the parties.

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