HS-201 Hydroxyethyl Piperidinol

What it is

Tiangang® HS-201 (1-(2-Hydroxyethyl)-2,2,6,6-tetramethyl-4-piperidinol) is a hindered amine intermediate. These are the raw materials or monomers used to build hindered amine light stabilizers. They are not end-use additives: the buyer still polymerises, esterifies or aminates them into finished grades such as 944, 622 or 2020. Product identifiers: chemical name 1-(2-Hydroxyethyl)-2,2,6,6-tetramethyl-4-piperidinol; CAS 52722-86-8; molecular weight 201.31; melting point 180–184 °C.

Technical data

Molecular weight around 201 — low-MW territory: fast diffusion and early onset, at the cost of volatility and migration, which suits thin parts.Melting point 180–184 °C °C — the processing window needs to reach above it for uniform dispersion.

Where it is used, and at what loading

Downstream use concentrates on HALS synthesis; some grades also serve pharmaceuticals, agrochemicals, polymerisation inhibitors and epoxy curing. Specifications are usually tighter than for end additives, because purity, water and colour all carry into the next reaction step.

As a synthesis raw material it is charged by reaction stoichiometry, not by part loading.

Choosing between similar grades

Three things decide the choice for HS-201: molecular weight and volatility, basicity, and compatibility with the other components in the system. A dihydroxy piperidinol that can be polyesterified directly into polymeric HALS (the 622 route) or used as a light/heat stabiliser on its own; the bifunctional structure is the point.

Frequently asked questions

How much does intermediate purity affect downstream?

Directly. Impurities carry into the polymerisation and shift molecular-weight distribution and colour, which finally shows up as light-stabilising efficiency in the finished HALS. We control purity, water content and colour on these grades.

Why does one intermediate come in several specifications?

Because downstream processes differ. Polymerisation cares about monofunctional impurities, esterification about hydroxyl value, polymerisation inhibition about radical scavenging. The specification differences are downstream differences.

Can an intermediate be used directly as a light stabilizer?

A few can, where a low-MW piperidinol gives useful stabilisation in a specific system. Most cannot: the molecular weight is too low, so volatilisation and migration are too fast for long-service outdoor parts.

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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