UV curing refers to that under the irradiation of ultraviolet light, the photoinitiator absorbs the radiation energy of ultraviolet light and splits into free radicals to initiate the polymerization, crosslinking and grafting of prepolymer, and solidifies into network polymer in a very short time. As a result, UV coatings, inks, adhesives, etc. are transformed 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) Photoinitiators absorb ultraviolet light and become excited photoinitiators.

(2) The excited photoinitiator is unstable and easy to decompose to form free radicals.

(3) Free radicals interact with unsaturated groups in prepolymers to initiate addition, crosslinking or polymerization reactions to form free radical intermediates.

(4) Free radical intermediates can obtain long-chain or network polymer free radical intermediates through chain growth reaction.

(5) Long chain or network polymer free radical intermediates produce chain termination reaction, and the original liquid components are transformed into solid polymers.