UV curing is ultraviolet curing, UV is the abbreviation of ultraviolet UV rays ultraviolet, curing refers to the process of transforming substances from low molecules to polymers. UV curing generally refers to the curing conditions or requirements of coatings (paints), inks, adhesives (glues) or other potting sealants that need to be cured with ultraviolet light, which is different from heating curing, curing of adhesives (curing agents), natural curing, etc.
In the field of chemical polymers, UV is also used as the abbreviation of radiation curing, UV, that is, UV ultraviolet curing, is the use of UV ultraviolet light medium and short wave (300-800 nm) under UV radiation, liquid UV materials in the photoinitiator stimulated into free radicals or cations, thereby triggering the polymer material (resin) containing active functional groups polymerization into an insoluble and non-melting solid coating film, is a new technology of environmental protection and low VOC emissions emerging in the 60s of the 20th century. After the 80s of the 20th century, China has developed rapidly.
The oligomers have a high viscosity, and in order to facilitate construction and improve the curing speed of crosslinking, it is necessary to add monomers as reactive diluents to adjust the rheology of the resin. The structure of the reactive diluent has an important influence on the properties of the final coating film such as flowability, slip, wettability, swelling, shrinkage, adhesion and migration within the coating film. Reactive diluents can be monofunctional or multifunctional, the latter being better because it improves crosslinking at curing. The performance requirements for the reactive diluent are, dilution ability, solubility, odor, ability to reduce the viscosity of the medium, volatility, functionality, surface tension, shrinkage during polymerization, glass transition temperature (Tg) of the homopolymer, influence on the overall curing speed and toxicity. The monomer used should be a monomer that is irritating to the skin and whose value does not exceed 3 as determined by Draize. A typical monomer used as a reactive diluent is tripropylene glycol diacrylate (TPGDA).
Fast polymerization reverse applications in the chemical mechanism of UV curing are actually achieved by generating free radical reactions under suitable photoinitiators and/or photosensitizers and high-performance lighting conditions. Photoinitiators that generate free radicals and cationic intermediates can be used. However, in today’s industry, the former is often colored (that is, a photoinitiator that can produce free radicals).
At present, the most used ultraviolet wavelengths are 365nm, 253.7nm, 185nm, etc. Features include immediate drying, low operating costs, improved quality, reduced storage space, and clean and efficient. The lamp power used is generally more than 1000W, using ultraviolet UVA UVC, etc., of which UVC uses more amalgam lamps.
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