Light curing typeread count [1575] release time：2021-12-17 17:03:00
In photocuring technology, the wavelength and light intensity of the light source are two important physical factors in the photocuring reaction, which respectively determine whether the photocuring reaction can occur, the reaction mechanism, and the speed of the reaction. They will ultimately affect the performance of the material. The wavelength of the light source must match the absorption wavelength of the photoinitiator to trigger the photocuring reaction.
1.Free radical light curing
Free radical photocuring is a free radical photoinitiator that generates free radicals after exposure to light, and the free radicals initiate double bond polymerization and solidify. Free radical photocuring reaction speed is fast, and in traditional UV There are many free radical photocuring applications in the industry and the technology is highly mature.，Various types of monomers, resins and initiators，Has been applied on a large scale, not only has many options，And the material cost is relatively low.
Commonly used free radical photocuring monomers include acrylate, vinyl, and vinyl ether monomers.；The functionality can be1、2、3And many officials and so on.
Free radical photocurable resins include polyurethane acrylic ene Acid ester, glycidyl ene acid ester, polyester acrylic ene acid ester, and polyether acrylate, etc. Generally speaking ，Polyurethane acrylate has good flexibility and wear resistance, but due to the presence of a large number of amine ester bonds, there are a large number of hydrogen bonds within or between molecules.，Resin viscosity is usually higher；Epoxy acrylate has fast curing speed and high strength, but is brittle and prone to yellowing.；Polyester acrylate has better curing quality and wider adjustable range of resin properties.；Polyether acrylate has a large number of ether bonds in the molecular chain，The molecular chain has good flexibility and resistance to yellowing, but the material is relatively soft.，Poor mechanical strength, hardness and chemical resistance. The functionality of free radical photocurable resins is usually greater than 2。
There are many types of free radical photoinitiators，There are cracking type and hydrogen abstraction type photoinitiators.
2.Cationic light curing
Cationic photocuring is a cationic initiator that generates active center super protonic acid under light，Protonic acid triggers ring-opening curing of epoxy, oxetane or vinyl ether materials. Ring-opening curing of epoxy or oxetane has small volume shrinkage ，There are no advantages such as oxygen inhibition. However, cationic photocuring has a relatively long curing induction period and slow reaction speed. It is relatively rarely used in the field of traditional photocuring. There are few types of monomers, resins, and initiators, and there are few options. ，The cost of formula systems is higher than that of free radical systems.
Monomers that can be used for cationic photocuring include epoxy, oxetane, and vinyl ether monomers. The commonly used resin is mainly epoxy resin. Initiators mainly include sulfur 铓 salt, iodine 铓 Salts and sensitizers.
