Two visible light photoinitiators ECure CQ and ECure 784

Compared with UV curing, visible light curing has the advantages of radiation safety, high curing depth and low equipment price. Visible light Photoinitiators mainly include acylphosphonates, naphthalimides, anthraquinones, carbazoles, silicones, oxime esters, conjugated dyes, photoacidifiers and metal complexes. Today we recommend two of LIFTCHEM’s superior products, the visible light photoinitiators ECure CQ and ECure 784.

 

ECure CQ, camphoroquinone, CAS.: 10373-78-1, yellow crystalline powder, bicyclic monoterpenoid compound. There are pairs of enantiomers, the left hand is foliated yellow crystal, melting point 198-204℃, slightly soluble in hot water, insoluble in cold water, soluble in ethanol, ether. The maximum absorption wavelength is 468nm of visible light, and after absorbing light energy, it produces hydrogen grabbing effect with the co-initiator tertiary amine, leading to free radical polymerization and curing.

Camphorquinone is non-toxic to human body, has good biocompatibility, its long wave light absorption properties disappear after photolytic reaction, and has photobleaching effect, so it is very suitable for use as dental light curing materials. ECure CQ/ amine, ECure CQ/ diphenyl (2,4, 6-trimethylbenzoyl) -phosphine oxide (ECure TPO)/ amine photoinitiation systems are widely used in the field of dental resins.

 

ECure 784, Bis[2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl]titanocene, is orange powder, CAS: 125051-32-3, melting point 165 ~ 170℃.The maximum absorption wavelength is 398nm and 560nm. Can trigger polymerization curing under visible light or even suitable laser irradiation, such as AR-laser (488nm), FD-Nd/ YAG-laser (532nm)

 

ECure 784 has good photoactivity, thermal stability and low toxicity. The photoinitiating process of ECure 784 is neither pyrolysis type nor hydrogen stripping type, but after absorbing light energy, photoisomerization becomes cycloamyl photoreaction intermediate, and ligand substitution occurs with oligomers and ester carbonyl groups of acrylates in active thinner, resulting in free radicals, polymerization and crosslinking. It is suitable for thick coating and dark curing system, can cure more than 70μm thick coating and black, red and high pigment coating. It has an ultra-wide visible light absorption band, can make full use of the light source, so it has a high sensitivity and photoinitiation activity, in the acrylate system, it just needs 0.8MJ/cm2 of 488nm light to trigger polymerization. The fragments after photolysis are complexed by acrylic ester, and will not migrate to the surface, so it is safe and environmentally friendly.