Chemical System of UV Radiation Curing

The chemical formulations that have the reaction activity constitutes the chemical system of the radiation curing, which generally include oligomers, monomers, photo-initiators, auxiliaries and so on.

The oligomer plays an extremely important role in the radiation curing formulation, which determines the overall performance of coating, ink, adhesives or other base materials after radiation curing. The oligomers are a kind of polymer with unsaturated double bond structure, which can further react and expand into cross-linked solidified body. Therefore, it is also called prepolymer. Most oligomers are different types of acrylic acid resin, and the molecular weight is generally small. Monomers are the most basic unit  of organic synthetic materials. In addition curing, single paralysis is mainly used as a diluent to reduce the viscosity of the chemical system. UV / EB curing monomer is generally an active diluent, which not only regulates the formulation viscosity, but also contains one or more double bonds in the molecular structure, which is called single-functional group active monomer or multi-functional group active monomer. The active monomers can react with oligomers or other monomers, participate in the radiation curing process, and do not cause pollution to the atmosphere due to the absence of volatile substance.

The photoinitiator produces free radicals and cations under the action of ultraviolet light. Both of these particles are high-energy active groups in the chemical system, which is beneficial to the cross-linking curing of unsaturated double bonds of monomers, oligomers and polymers. It is worth pointing out that EB curing does not require a photoinitiator because the electrons themselves can trigger the cross-linking reaction of the chemical system. Although the auxiliary agent does not directly participate in curing process in radiation curing, its role cannot be ignored. The most commonly used auxiliaries are stabilizers, which are mainly used to prevent the gelation of formulation during storage, or to prevent the formulation system from curing automatically under dark light conditions. In addition, other auxiliaries, including pigments, dyestuffs, dimming agents, defoaming agents, leveling agents, adhesion promoters, etc., also play a different role in proving the final curing performance.

Development Tendency

Although the radiation curing has made great progress in the world, the main reason for its unsatisfactory industrialization is that many technological achievements are still in the stage of pilot and laboratory research.

First of all, the main development direction of radiation curing is to continue to play in the traditional manufacturing advantages, at the same time to the car and the building decoration market - the world’s largest coating market, which requires the radiation curing product performance to achieve the long-term outdoor weathering resistance standard.

The other development direction of radiation curing is to enter into the emerging information industry, specifically in the field of photo-conductive media, information system and telecommunication. This is a whole heart area is the UV / EB technology to display its own strong and wide world.