How to eliminate the irritating odor of UV ink?

Although UV ink is an environmentally friendly ink, it will inevitably produce irritating odors and bring a small amount of harm. It should be noted that the cheaper the UV ink, the greater its toxicity and harm.

Causes:

The irritating odor of UV ink is first of all the raw materials of the UV ink itself (such as monomer diluents, low molecular weight initiators, resin linkers and other raw materials), which are slowly emitted under certain conditions; secondly, after the UV ink is cured, the initiators, resins and other raw materials are cracked to produce aldehydes and sulfur irritating gases. At present, the main source of the irritating odor of most UV printing is the volatiles released before and after the UV ink itself is cured.

If some monomers or resins are not completely reacted, there are unreacted "acrylic acid" components, forming a pungent sour smell. In addition, if the monomer is of low molecular weight and low boiling point, it may volatilize a foul odor at room temperature, especially monofunctional monomers, such as IBOA (isobornyl acrylate). The solid components used in UV inks, such as pigments, fillers, waxes, etc., are basically odorless and can be ignored. If the monomers and resins used in UV inks are of good quality and there is no odor problem, then the UV initiator is the biggest source of irritating odor. And a UV ink often needs to add multiple initiators to complete thorough drying and curing.

Elimination method：

There are hundreds of types of initiators in use on the market, but the initiation efficiency, price, color depth, and scope of use vary greatly. At present, most domestic printing companies use 907 initiator in UV inks, and its chemical name is 2-methyl-1-(4-methylthiophenyl)-2-morpholine-1-propanone. This type of initiator is moderately priced and has high initiation efficiency, but after curing, it will crack into an unpleasant "methylthio group". EDAB initiator and BP benzophenone initiator will also produce odor after curing. In order to reduce the odor problem of the initiator, these initiators can be omitted. Using some high-end initiators such as 369, EHA, TPO, etc., of course, the ink cost will increase accordingly. It can be said that choosing a better low-odor UV ink is one of the keys to solving the irritating odor problem.

In addition, ventilation fans are installed indoors, and separate compartments are built if conditions permit. The printed products can be left for 4 hours to wait for them to completely cure and the odor to evaporate.