Principle and characteristics of the hottest LED c

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Principle and characteristics of LED curing ink

1 development of LED ink

in 1969, UV curing ink was first used in paperboard (carton) printing in the United States, which took the first step of practicality. In 1971, two years later, Japan began to apply it to metal printing and label printing. After that, the characteristics of UV ink, such as rapid curing, solvent-free and powder free, were brought into play. The advantages of UV ink in the printing site (improvement of working environment, short delivery period, reduction of inventory, space saving, etc.) were recognized, and its use expanded rapidly

however, in the past, UV light sources used in the printing industry generally used high-pressure mercury lamps, metal halogen lamps and other light sources. Due to the large-scale lamps and power supply devices, users are worried about the damage of printing machines and substrates caused by large power consumption and heat generation, as well as the generation of ozone during use. However, in recent years, a light-emitting diode (LED) capable of emitting ultraviolet light has been developed, and the special offset printing ink (FD LED series) that is used with it to cure instantly under led ultraviolet light has been developed by Toyo ink (1) measurement and control system, operation software and data processing system Manufacturing Co., Ltd

this paper compares the difference between traditional lamp light source and LED light source from the environment of UV curing ink, and introduces the principle and characteristics of LED curing ink

2 environmental coordination of UV inks

1) non VOCs inks

the so-called VOCs is the strategy that volatile organic compound must be installed with office2000 NDS, that is, the general term of volatile organic compounds. VOCs diffused in the atmosphere has a stronger greenhouse effect than carbon dioxide, the material of global warming listed in the article. In addition, VOCs can react in the sun and become oxidants (the substance causing photochemical smoke). Therefore, countries around the world, led by developed countries, have formulated strict regulations on their emissions around the world

general offset printing inks are divided into thermosetting rubber wheel inks and sheet fed offset printing inks, both of which contain petroleum solvents. Drying process of sheet fed offset printing ink: when the ink is transferred to the paper, the solvent separates from the paper and separates out the resin components. At the same time, the vegetable oil components in the ink react with oxygen in the air to form a hardened ink film. Drying process of rubber wheel ink: after printing, after heating, the solvent in the ink evaporates, and resin components are separated out, thus forming an ink film

about VOCs emissions. Sheet fed offset printing ink has the advantage of no energy consumption during drying. However, due to the need for a long drying time, strictly speaking, in this drying process, the VOCs components in the ink are either left on the substrate or gradually released to the atmosphere. The rotary offset printing ink releases VOCs components after heating, evaporation and drying. These VOCs gases are decomposed into water and carbon dioxide after being treated in the drying oven and reburning chamber. Therefore, there are countermeasures from the perspective of VOCs

on the other hand, UV curable inks activate the photopolymerization initiator through ultraviolet irradiation, thus promoting the combination of monomers and oligomers (low molecular components) contained in the ink through chemical reaction to form a hardened ink film. Since there is no solvent producing VOCs in UV ink, of course, VOCs will not be discharged into the atmosphere. Therefore, UV ink is an environment-friendly ink system

2) earth ring warming

carbon dioxide has just been mentioned. Here are some examples from the point of view that it has become one of the substances that cause earth ring warming. In the drying project of rubber wheel printing, carbon dioxide will be generated due to the combustion of gaseous fuel. In particular, as the cost of preventing VOCs in the ink from being discharged into the atmosphere, it is necessary to use a device such as a reburning chamber to burn the volatile VOCs. At this time, carbon dioxide will be generated

uv curable inks do not contain solvents, so it is not necessary to further improve the success rate of the experiment. With the above-mentioned hot air drying device, the energy efficiency ratio required for ink curing can be said to be more than 5 times that of rubber wheel printing. Therefore, the total amount of carbon dioxide generated when using UV inks is less. The experimental machine is famous all over the world. From the perspective of global warming, it can be said that it is also a system beneficial to the environment

3) powder spraying

in order to prevent the back of the sheet fed offset printing from sticking dirty, corn flour and the like are sprayed evenly on the printing sheet by powder spraying. The result of powder spraying will lead to the dirt of the printing machine and the printed matter, and also pollute the surrounding environment of printing, causing trouble to the on-site operators

uv printing does not need powder spraying because it is instant curing. From the perspective of working environment, UV ink is a better ink system than sheet fed offset oily ink

as mentioned above, UV ink printing system has the advantages of energy saving, space saving and short curing time compared with the printing system using traditional sheet fed oily ink and rotary offset ink, and its application has expanded rapidly in recent years

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