PI 369 is an α-aminoketone Type I photoinitiator exhibiting very strong UV-A absorption (λmax ≈ 330–385 nm) and excellent solubility in acrylic monomers, oligomers and most organic solvents. Upon irradiation it undergoes α-cleavage to generate both benzoyl and amine-alkyl radicals, giving rapid, low-odour, low-yellowing cure of pigmented or clear UV-LED/mercury-lamp systems. The product is practically insoluble in water (5.9 mg L⁻¹ at 20 °C), has good thermal stability (m.p. 115–119 °C) and low migration, and is especially recommended for coloured inks, photoresists and food-contact coatings. Commercial material is supplied at ≥ 99 % purity and remains stable for ≥ 2 years when stored sealed at < 25 °C away from light .
Key Physicochemical Data:
Melting point: 115–119 °C
Boiling point: 528 °C / 760 mmHg (predicted)
Density: 1.094 g cm⁻³ (20 °C, predicted)
Flash point: > 110 °C (closed cup, predicted)
Log P (octanol/water): 4.1 at 25 °C
Vapour pressure: < 0.01 Pa at 25 °C
Typical Uses:
High-performance Type I photoinitiator for UV-LED or mercury-lamp curing of offset, flexo and screen inks, pigmented coatings, photoresists and printing plates at 2–4 % w/w; offers fast surface cure, excellent through-cure and low migration .
Synergist with benzophenone, 184 or TPO for thick-section (> 4 mm) and highly coloured (TiO₂, carbon-black) formulations .
Building block for low-odor, low-yellowing UV-curable systems in food-contact and cosmetic packaging due to its superior solubility and thermal stability .
Quality Specification (Commercial Grade):
Purity (HPLC): ≥ 99 %
Water content (KF): ≤ 0.3 %
Loss on drying: ≤ 0.5 %
Residue on ignition: ≤ 0.1 %
Heavy metals: ≤ 20 ppm
Hazard Statement:
Harmful to aquatic life with long-lasting effects (H413); causes skin and eye irritation (H315 + H319). Avoid release to the environment; use gloves, goggles and adequate ventilation. Store in a cool, dry place away from oxidants and light. SDS available on request.
