The uses of free-Radical Photoinitiator and cationic Photoinitiator

Photoinitiators, also known as photosensitizers or photocuring agents, are commonly used in photocuring systems, such as UV adhesives, UV coatings, UV inks, etc. They absorb a certain wavelength of energy in the ultraviolet light region (250-420nm) or visible light region (400-800nm), which can generate free radicals, cations and some others, thereby initiating polymerization, crosslinking and curing of monomers. 

Free-Radical Photoinitiator

Depending on their reaction, free-radical photoinitiators are mainly divided into the following two categories:

Norrish Type I photoinitiator

Norrish Type II photoinitiator

Norrish Type I photoinitiators, also called cleavage-type free radical photoinitiators, are mostly aryl alkyl ketone derivatives. Representative ones include benzoin derivatives, benzil ketal derivatives, dialkoxy acetophenone, α-hydroxyl alkyl phenone, α-aminoalkyl phenone, acyl phosphine hydride, esterified oxime ketone compound, aryl peroxy ester compound, halogenated methyl aryl ketone, organic sulfur compound, benzoyl formate, etc.

Norrish Type II photoinitiators, also called hydrogen abstraction type photoinitiators, are generally based on aromatic ketone structures, and also include certain fused-ring aromatic hydrocarbons, which have certain light absorption properties, and the matching co-initiator, namely hydrogen donor, itself is not absorpted in the range of commonly used long-wave ultraviolet light. The hydrogen abstraction type photoinitiator absorbs light energy and has bimolecular interaction with the co-initiator in the excited state to generate active free radicals.

Cationic Photoinitiator

Cationic photoinitiators are also very important type of photoinitiators, including diazonium salts, diaryliodonium salts, triarylsulfonium salts, alkylsulfonium salts, iron aromatic hydrocarbon salts, sulfonyloxy ketones and triarylsiloxane ether. They are suitable for cationic photopolymerization with monomers which mainly include epoxy compounds and vinyl ethers, followed by lactones, acetals, cyclic ethers, etc.

Shanghai Massive Chemical Technology Co., Ltd. has many years of experience in photoinitiators and other products. Due to stable quality and extremely competitive price, our products have been sold to numerous countries at home and abroad.

2-Propenoic acid,4-benzoylphenyl ester is a kind of photoinitiator developed by Shanghai Massive Chemical Technology Co., Ltd.