UV curing principle and process
UV curing means that under the irradiation of ultraviolet light, the photoinitiator absorbs the radiation energy of the ultraviolet light and then splits into free radicals, triggering the polymerization, crosslinking, and grafting reactions of the prepolymer, and curing into a network in a very short time. High polymer. As a result, UV coatings, inks, adhesives, etc. are converted from liquid to solid in a few seconds to form patterns.
The UV curing process can generally be divided into the following five stages:
(1) The photoinitiator absorbs ultraviolet light and becomes an excited state photoinitiator.
(2) The photoinitiator in the excited state is unstable and easily decomposes to form free radicals.
(3) The free radical interacts with the unsaturated group in the prepolymer to initiate an addition, crosslinking or polymerization reaction to form a free radical intermediate.
(4) The free radical intermediate obtains a long-chain or network polymer free radical intermediate through a chain extension reaction.
(5) The long-chain or network-shaped polymer free radical intermediate produces a chain termination reaction, and the original liquid component is converted into a solid polymer.