Fotoinitiaattorit

Fotoinitiaattorit, also known as photoinitiators, are chemical compounds that initiate a chemical reaction upon exposure to light, typically ultraviolet (UV) or visible light. This process is called photoinitiation. When a photoinitiator absorbs photons of light, it becomes excited and undergoes a transformation, often breaking down into highly reactive species such as free radicals or cations. These reactive species then interact with monomers or oligomers present in a formulation, initiating polymerization or crosslinking reactions.

The ability of photoinitiators to trigger reactions with light makes them crucial components in various photopolymerization applications. These applications include UV-curable coatings, inks, adhesives, and 3D printing resins. UV curing is a rapid and energy-efficient process that offers several advantages over traditional thermal curing methods, such as reduced energy consumption, lower VOC emissions, and faster processing speeds.

The selection of a specific photoinitiator depends on several factors, including the wavelength of the light source, the chemical structure of the monomers or oligomers being polymerized, the desired cure speed, and the final properties of the cured material. Different types of photoinitiators exist, broadly categorized into Type I (cleavage type) and Type II (hydrogen abstraction type) photoinitiators, each with distinct mechanisms of action. Type I photoinitiators cleave upon light absorption to form radicals directly, while Type II photoinitiators require a co-initiator or synergist to abstract a hydrogen atom and generate initiating radicals.