Learn about the course of UV curable ink from its appearance to commercial application

Ink is an essential consumable in the printing industry, and it can even be said that there would be no printing industry today without it, but the unfriendly environment of ink makes it in a rather embarrassing situation. Many enterprises are developing new environmentally friendly inks. For example, the emergence of UV Ink and its commercial application are the result of its rapid curing, solvent-free, powder-free and other characteristics.

The development of LED ink

In 1969, the United States used Uv Curable Ink for cardboard (carton) printing for the first time, which took the first practical step. Two years later, Japan began to apply it to metal printing and label printing. In the future, the characteristics of UV ink, such as rapid curing, solvent-free and powder-free, were brought into play, and the advantages of UV ink in printing field (improvement of working environment, short delivery period, reduction of inventory, space saving, etc.) were recognized, and its use was rapidly expanded.

However, in the past, the ultraviolet light sources used in the printing industry generally used high-pressure mercury lamps and metal halogen lamps. Because of 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 high calorific value, 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 (FDLED series) which can be instantly cured under LED ultraviolet light for matching use has been developed by Toyo Ink Manufacturing Co., Ltd. in Japan.

Environmental harmony of UV ink

Non-VOCS ink
The so-called VOCS is the abbreviation of Volatile Organic Compounds, that is, the floorboard of volatile organic compounds. VOCS diffused in the atmosphere have a stronger greenhouse effect than carbon dioxide, which is one of the substances listed in this paper. In addition, VOCS can react in the sun and become oxidants (the cause of photochemical smoke). Therefore, countries in the world, led by developed countries, have formulated strict regulations on their emissions around the world.
General offset Printing Ink can be divided into heat-fixing web offset ink and sheet-fed offset printing ink, both of which contain petroleum solvents. Drying process of sheet-fed offset printing ink: when the ink is transferred to the paper, the solvent is separated from the paper to separate out the resin component, and at the same time, the vegetable oil component in the ink reacts with oxygen in the air to form a hardened ink film. Drying process of web offset 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 when drying, but it needs a long drying time. Strictly speaking, during this drying process, VOCS in the ink either remain on the substrate or are gradually released to the atmosphere. VOCS are released from web offset ink after heating, evaporation and drying. These VOCS are decomposed into water and carbon dioxide after passing through the drying oven and then being treated in the reburning chamber, so there are countermeasures from the point of view of VOCS.

On the other hand, UV curable ink activates the photopolymerization initiator by ultraviolet irradiation, and then promotes the combination of monomers and oligomers (low molecular components) contained in the ink through chemical reaction to form a hardened ink film. Because there is no solvent to produce VOCS in UV ink, and of course no VOCS will be discharged into the atmosphere, it can be said that UV ink is an environmentally friendly ink system.

Global warming

As for carbon dioxide, we have just talked about it, and here we will take it as an example from the point of view that it becomes one of the substances that cause global warming. In the drying project of web offset ink printing, carbon dioxide will be produced because of the combustion of gas fuel, especially as the price of not letting VOCS in ink be discharged into the atmosphere, it is necessary to use a device such as a reburning chamber to burn off the volatilized VOCS, and then carbon dioxide will be produced.

Because UV curable ink contains no solvent, there is no need to configure the hot air drying device as mentioned above, and the energy efficiency ratio required for ink curing can be said to be more than five times that of web offset ink printing. Therefore, the total amount of carbon dioxide generated when using UV ink is small, and it can be said that it is also a system beneficial to the environment from the point of view of global warming.

Spray the powder
In order to prevent the back of sheet-fed offset printing from sticking dirty, corn flour is sprayed evenly on the printed sheet by powder spraying, which leads to the dirt of the printing machine and printed matter, and also pollutes the surrounding environment of printing, which brings troubles to the field operators.
UV printing is instant curing without powder spraying. Compared with sheet-fed offset printing oily ink, UV ink is a better ink system from the perspective of working environment.
As mentioned above, compared with the traditional printing systems using sheet-fed oily ink and web offset ink , UV ink printing system has the advantages of energy saving, space saving and short curing time, and its application has expanded rapidly in recent years.