A high-activity cationic photoinitiator supplied either as neat crystals or as a 50 % solution in propylene carbonate. The triarylsulfonium core absorbs strongly in the 250–330 nm region and photolyzes to generate super-acid (HPF₆), initiating rapid cationic polymerisation of epoxides, vinyl ethers, oxetanes and glycidyl systems. It offers low odour, low yellowing, excellent through-cure (> 4 mm) and good thermal latency. Commercial material is stable for ≥ 2 years when stored sealed at 2–8 °C away from moisture and light.
Key Physicochemical Data:
Melting point: 112–114 °C (MeOH solvate)
Density: 1.31 g cm⁻³ (20 °C)
Flash point: > 150 °C (closed cup, predicted)
Log P (octanol/water): 10.3 (predicted)
Water solubility: 74 mg L⁻¹ at 20 °C
Vapour pressure: 0.002 Pa at 20 °C
Typical Uses:
Universal cationic photoinitiator for UV-LED or mercury-lamp curing of clear and pigmented epoxies, vinyl ethers, oxetanes and hybrid UV-cationic systems at 0.5–4 % w/w.
Deep-section (> 3 mm) and high-speed printing inks, solder-mask, optical-fibre coatings, 3-D stereolithography resins.
Synergist with free-radical photoinitiators for hybrid cure or dual-cure formulations.
Quality Specification (Commercial Grade):
Purity (HPLC): ≥ 98 %
Water content (KF): ≤ 0.3 %
Chloride: ≤ 100 ppm
Heavy metals: ≤ 20 ppm
Transmittance (500 nm, 10 % in PC): ≥ 85 %
Hazard Statement:
Causes skin and eye irritation (H315 + H319); harmful to aquatic life with long-lasting effects (H413) . Avoid release to the environment; use gloves, goggles and local exhaust. Store in tightly closed containers at 2–8 °C under nitrogen. SDS available on request.
