UV (ultraviolet light curing) ink is a type of ink that polymerizes monomers into polymers through different wavelengths and energies of ultraviolet light under ultraviolet irradiation, thereby achieving ink film formation and drying. It has been widely used in the printing field due to its advantages such as fast drying speed, good gloss, bright colors, water resistance, solvent resistance, and good wear resistance. However, the curing time of UV ink under fluorescent lamps is a relatively complex issue that requires further exploration.
The curing principle of UV ink
The curing of UV ink mainly relies on the radiation of ultraviolet light. Under the irradiation of ultraviolet light, the photopolymerization initiator in the ink absorbs photons of a certain wavelength, excites them to an excited state, forms free radicals or ions, and thus triggers polymerization reactions between monomers, causing the ink to solidify rapidly. This curing method has the advantages of fast speed, high efficiency, energy saving and environmental protection.
Light source characteristics of fluorescent lamps
A fluorescent lamp is a low-pressure cold light source that emits visible light by exciting gas and fluorescent powder. Its light source is soft and free of infrared radiation, capable of emitting various beautiful colored lights. However, the ultraviolet intensity emitted by fluorescent lamps is relatively low, and the wavelength distribution is different from that of professional UV curing lamps. Therefore, fluorescent lamps may have limitations in providing the energy required for UV ink curing.
Curing time of UV ink under fluorescent lamp
Due to the low intensity of ultraviolet radiation emitted by fluorescent lamps and the possibility that the wavelength distribution may not fully meet the requirements for UV ink curing, the curing time of UV ink under fluorescent lamps is relatively long, and it may even not be completely cured. Specifically, the length of curing time depends on various factors, including the type, color, and thickness of the ink, as well as the power, irradiation distance, and irradiation time of the fluorescent lamp.
Generally speaking, UVLED ink can cure within 1 second under professional UV light source irradiation. And thermosetting ink needs to be cured at a specific temperature, usually taking 1.5 to 3 minutes. In contrast, the curing time of UV ink under fluorescent lamps may be greatly prolonged, and even the expected curing effect may not be achieved.
Influencing factors and suggestions
Ink types: Different types of UV inks have varying absorption and response capabilities to ultraviolet radiation, resulting in differences in curing time. When selecting ink, it should be chosen according to specific application scenarios and requirements.
Ink color: Black and blue inks require higher energy to cure due to their strong ability to absorb ultraviolet radiation. Yellow and red inks are relatively easy to cure. In order to ensure sufficient curing of dark ink and prevent excessive curing of light ink, the principle of printing with dark ink first and printing with light ink later should be followed.
Ink thickness: The thickness of ink also affects the curing time. Thicker ink requires longer irradiation time to fully cure. Therefore, the thickness of ink should be reasonably controlled during the printing process.
Power and irradiation distance of fluorescent lamps: The power and irradiation distance of fluorescent lamps also have a significant impact on curing time. The higher the power and the closer the irradiation distance, the shorter the curing time. However, excessive power and close irradiation distance may also lead to excessive solidification or burning of ink.
Environmental factors: Temperature, humidity, and other environmental factors may also affect the curing of UV ink. Curing under suitable temperature and humidity conditions can improve the curing effect.
In summary, the curing time of UV ink under fluorescent lamps is a relatively complex issue that requires comprehensive consideration of multiple factors. To ensure the curing quality of ink, it is recommended to use professional UV curing equipment for curing. If curing must be carried out under fluorescent lamps, the irradiation time should be appropriately extended, and the curing of the ink should be closely monitored to ensure the expected curing effect is achieved.