Tiangang® HS-770

What it is

Tiangang® HS-770 is a hindered amine light stabilizer (HALS). HALS trap the radicals formed when a polymer photo-oxidises and regenerate in the process, so the protection window is longer than that of a UV absorber, which is consumed as it works. Product identifiers: chemical name Bis(2,2,6,6-tetramethyl-4-piperidyl)-sebaceate; CAS 52829-07-9.

Technical data

Chemical name	Bis(2,2,6,6-tetramethyl-4-piperidyl)-sebaceate
CAS number	52829-07-9
Structure
Description	Tiangang® HS-770 is a highly effective radical scavenger that protects organic polymers against degradation caused by exposure to ultraviolet radiation. It is widely used in a variety of applications including polypropylene, polystyrene, polyurethanes, ABS, SAN, ASA, polyamides and polyacetals. Its high effectiveness as a light stabilizer makes it well suitable for applications in both thick section and films, independent of the thickness of the articles. Combined with Tiangang’s other HALS products, Tiangang® HS-770 displays strong synergistic effects.

Where it is used, and at what loading

Suitable for polyolefins (PP, PE), polyurethane, polyamide, polyacetal and polyester. Thin and thick parts call for different grades: thin sections suffer from volatilisation and migration, thick sections from surface bloom.

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 HS-770: molecular weight and volatility, basicity, and compatibility with the other components in the system. Grade 770 has low molecular weight and diffuses quickly, which suits thin parts and fast onset; long-service thick parts usually pair it with HS-950.

Frequently asked questions

Is this grade meant for thin or thick parts?

It depends on molecular weight and migration tendency. Low-MW grades diffuse quickly and act early but volatilise and migrate over time; high-MW grades (HS-950, HS-362, BW-10LD) suit long-service outdoor parts. Tiangang offers both, so the choice follows wall thickness and design life.

Is it worth combining with a UV absorber?

Yes, they cover different stages. The UV absorber shields incoming UV energy; the HALS scavenges radicals that have already formed. Agricultural film, automotive exterior and PV backsheet usually need both to reach their design life.

What happens if the loading is too high?

Beyond the compatibility limit the additive blooms to the surface, which wastes material and harms appearance and print adhesion. Protection also stops scaling linearly. Our practice is a loading ladder on the actual system, then fix the cost-performance knee.

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.

Upgrade path

See Tiangang® T-78. Where you need a complete package for automotive or PP/EPDM systems, use T-78: a monomeric HALS and antioxidants pre-blended in ratio, which removes individual weighing and the chance of a mixing error. For general thick mouldings where volatilisation is the concern, evaluate HS-788 or HS-950.

T-78 is an application-specific one-pack, not a like-for-like replacement for 770: outside automotive work, confirm the carrier matches your matrix first.

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