UV Absorber 292 NEW

UV Absorber 292 is actually a trade name, primarily associated with BASF's Tinuvin® 292. It is NOT a UV absorber (UVA). It is a Hindered Amine Light Stabilizer (HALS), which works through a fundamentally different mechanism. Here's a detailed breakdown:

1. Correct Classification: Hindered Amine Light Stabilizer (HALS)

• Crucially, HALS do not absorb UV light like benzotriazoles (e.g., UV 1130) or triazines.

• They function as highly efficient radical scavengers to inhibit the degradation process after UV light has initiated it.

2. Chemical Composition:

• The main component is typically Bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate combined with Methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate.

• This specific blend is often referred to as a "NOR HALS" due to the presence of the N-CH3 group (instead of N-H), which enhances its performance, especially in acidic environments and agricultural films.

3. Key Properties:

• Physical Form: Clear, viscous liquid (amber to yellow).

• Solubility: Excellent solubility in common organic solvents. Good compatibility with a wide range of polymers.

• Low Volatility: Suitable for processing temperatures up to around 280°C (536°F).

• Low Basicity: The NOR structure makes it less basic than traditional HALS, improving compatibility in systems sensitive to alkalinity (e.g., acid-catalyzed coatings, halogen-containing polymers like PVC).

4. Primary Function (Mechanism):

• Radical Scavenging: Inhibits the photo-oxidative degradation cycle:

• Regenerative: The active nitroxyl radical (>NO•) formed during stabilization can be regenerated back to the active amine form, making HALS very efficient at low concentrations.

1. UV light breaks bonds in the polymer, creating free radicals (R•).

2. These radicals react with oxygen to form peroxy radicals (ROO•).

3. ROO• attacks the polymer chain, creating hydroperoxides (ROOH) and new radicals (R•), propagating the cycle.

4. HALS (like 292) interrupt this cycle by scavenging the peroxy radicals (ROO•) and decomposing hydroperoxides (ROOH).

5. Typical Applications:

• Polyolefins: PP (especially for automotive parts, tapes, fibers, films), PE (films, pipes, geomembranes).

• Styrenics: ABS, HIPS.

• Elastomers: EPDM, TPOs.

• Adhesives & Sealants.

• Coatings: Widely used in automotive coatings (clearcoats, basecoats), industrial coatings (wood coatings, coil coatings), and architectural coatings. Often used synergistically with UV absorbers (like Tinuvin 1130).

• Plastics:

• Agricultural Films: Its low basicity makes it suitable for films exposed to pesticides/acidic environments.

6. Advantages:

• Liquid Form: Easy handling, pumping, and incorporation.

• High Effectiveness: Excellent long-term thermal and light stabilization, especially against surface degradation (cracking, loss of gloss).

• Synergy with UVAs: Dramatically enhances the overall weatherability performance when combined with UV absorbers (like benzotriazoles).

• Low Basicity (NOR type): Better compatibility in demanding systems.

• Good Extraction Resistance: Performs well in applications exposed to water or solvents.

7. Important Considerations & Clarifications:

• Trade Name Confusion: "UV Absorber 292" is a misnomer. It's a HALS, not a UV absorber. The name comes from BASF's Tinuvin® 292 product line.

• Tinuvin 292 vs. Tinuvin 292 HP: "292" typically refers to the standard liquid NOR HALS blend described above. "292 HP" (High Performance) usually refers to Oligomeric Hindered Amine Light Stabilizers (like Chimassorb 2020 or Tinuvin 111/622), which are higher molecular weight solids offering lower volatility and migration resistance for demanding applications. Always check the exact technical data sheet.

• Dosage: Typical loadings range from 0.1% to 1.0% by weight, depending on polymer/coating, thickness, required durability, and presence of other stabilizers (especially UVAs).

• Safety: Handle according to the SDS. Generally considered low hazard with proper precautions (gloves, eye protection).

• Regulatory: Ensure compliance (REACH, FDA, etc.) for the specific application. Consult supplier documentation.

In Summary:

• Tinuvin® 292 (often called "UV Absorber 292") is actually a liquid NOR-type HINDERED AMINE LIGHT STABILIZER (HALS).

• It works by scavenging free radicals generated during UV exposure, interrupting the degradation cycle.

• It is NOT a UV absorber and does not absorb UV light itself.

• It's highly effective, especially when combined with UV absorbers (like Tinuvin 1130), in protecting coatings (automotive, industrial) and plastics (PP, PE, etc.) from photo-oxidative degradation (loss of gloss, cracking, chalking, embrittlement).

• Its liquid form, low basicity, and good compatibility make it widely applicable.

Always refer to the specific supplier's technical data sheet (TDS) and safety data sheet (SDS) for the exact product you are using.