UV ultraviolet glue is also known as shadowless glue, UV glue, photosensitive glue, or ultraviolet curing glue. It refers to a type of adhesive that can only be cured by exposure to ultraviolet light. It can be used as a bonding agent, or as a glue for paints, coatings, and inks, etc. UV is the abbreviation of the English word "Ultraviolet Rays", which means ultraviolet light. Ultraviolet (UV) is invisible to the human eye and is a segment of electromagnetic radiation outside the visible light range, with a wavelength of 10-400nm. The curing principle of shadowless glue is that the photoinitiator (or photosensitive agent) in the UV curing material absorbs ultraviolet light and then generates free radicals or cations after absorbing the ultraviolet light, triggering the polymerization, cross-linking, and branch-point chemical reactions of the monomers, causing the adhesive to change from a liquid state to a solid state within a few seconds. 

UV ultraviolet glue is an important branch of the developing radiation-curing materials. Although UV ultraviolet glue accounts for a relatively small proportion of the entire adhesive, its features of no solvent evaporation, fast curing speed and energy saving have drawn increasing attention. Especially in some places where traditional adhesives cannot be used, UV ultraviolet glue can be used for bonding. 

According to the "China UV Ultraviolet Glue Market Research and Investment Prospects Report" released by China Business Intelligence Network, in recent years, UV ultraviolet glue, as a new type of environmentally friendly adhesive, has seen a rapid expansion in its varieties, quality and applications, becoming one of the fastest-growing adhesive types. It has gradually replaced traditional curing adhesives in many occasions and is playing an increasingly important role. In the future, the production and demand of UV ultraviolet glue in China will continue to grow rapidly, and it will become an important UV non-illuminating adhesive production and consumption market in the world. 

In order to expand the spectral response range of photopolymerization, the development of new high-sensitivity and low-energy, long-wave-sensitive photoinitiating systems has become a new research hotspot. Additionally, during the curing process of photopolymer adhesives, there are common drawbacks such as limited curing depth, coloration, and the difficulty of applying opaque materials. Therefore, the research on new initiators and new curing methods is particularly important. At the same time, photopolymer adhesives will also develop towards high-performance and environmentally friendly directions.