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Chemical structure of 2-(2H-Benzotriazol-2-yl)-4,6-di-tert-pentylphenol | 25973-55-1
CAS: 25973-55-1
SKU: S2802
Shop 2-(2H-Benzotriazol-2-yl)-4,6-di-tert-Pentylphenol | Sarchem Labs | SKU: S2802
Synonyms: UV-328; UV Absorber 328; 2-(3,5-Di-tert-amyl-2-hydroxyphenyl)benzotriazole
Chemical structure of 2-(2H-Benzotriazol-2-yl)-4,6-di-tert-pentylphenol | 25973-55-1
Tinuvin 328 is a hydroxyphenylbenzotriazole-class UV light absorber historically used to stabilize plastics, coatings, and elastomers against sunlight degradation. As of 2023–2025, this substance’s regulatory status has changed fundamentally: it is now listed for global elimination under the Stockholm Convention, with EU implementation already in force. This section is written to inform an internal compliance decision, not to market the product for continued open sale — please read the regulatory status below in full before deciding how (or whether) to publish this page.
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Specifications

Melting Point82°C (per Sarchem's existing published data)
ColorYellow
Formula Weight351.49
Physical FormCrystal-powder
Chemical Name or Material2-(3,5-Di-tert-amyl-2-hydroxyphenyl)benzotriazole
Molecular Weight351.49 g/mol
CAS Number25973-55-1
ApplicationsUV stabilization of plastics, coatings, and elastomers (styrene polymers, acrylics, polyolefins, polyurethanes, PVC, adhesives)

Applications

UV stabilization of plastics, coatings, and elastomers (styrene polymers, acrylics, polyolefins, polyurethanes, PVC, adhesives)
Automotive and aerospace materials manufacturing (per its listed applications)

Product Description

What is Tinuvin 328?

Tinuvin 328 is a benzotriazole-based UV absorber that historically protected polymer and coating materials from photodegradation and discoloration by absorbing damaging UV wavelengths. It was widely used across styrene, acrylic, polyolefin, and PVC manufacturing before its 2023 Stockholm Convention listing as a persistent, bioaccumulative substance of global concern.

Historical Uses of Tinuvin 328

Prior to its POPs listing, this compound was used across a wide range of plastics, coatings, and elastomer manufacturing to prevent UV-induced degradation — automotive components, aerospace materials, and outdoor-exposed plastics were common applications.

Safety Information

  • Signal Word: Warning | Hazard Statements: H373 (Causes damage to organs through prolonged or repeated exposure), H413 (May cause long-lasting harmful effects to aquatic life)
  • Regulatory Status: Stockholm Convention Annex A (global elimination, 2023); EU POPs Regulation Annex I (Regulation (EU) 2025/843, effective February 26, 2025)

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FAQs: Shop 2-(2H-Benzotriazol-2-yl)-4,6-di-tert-Pentylphenol

Its status changed significantly in 2023–2025: it's now listed for global elimination under the Stockholm Convention and has been added to the EU's POPs Regulation, with only narrow, time-limited exemptions remaining. Confirm current status with legal/compliance for your specific jurisdiction and use case before selling or marketing this product.

It was found to be persistent, bioaccumulative, and subject to long-range environmental transport — the criteria used to list substances under the Stockholm Convention as Persistent Organic Pollutants (POPs).

Historically, as a UV light stabilizer protecting plastics, coatings, and elastomers from sunlight-induced degradation across automotive, aerospace, and general polymer manufacturing.

351.49 g/mol.