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What types of solvents are used in flexographic inks

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A solvent is a substance, which has the ability to dissolve a compound. Used in a variety of applications, from surface cleaning to the formulation of chemicals, inks, paints and pharmaceuticals.

In the context of flexographic printing, solvents play an important role, as they are used to dilute the ink components, control its viscosity, facilitate the transfer of the ink to the substrate and allow it to dry or cure. Among the most used we have:

• Hydrocarbon-based solvents: They are derived from organic compounds containing carbon and hydrogen, often obtained from petroleum distillation processes. Common examples hexane, heptane and naphtha.

• Ether-based solvents: They result from the reaction between an acid and an alcohol. Examples ethyl acetate, butyl acetate and propyl acetate.

• Alcohol-based solvents: Such as ethanol and isopropanol, they are common in some ink formulations. These can be obtained naturally through the fermentation of plant materials or synthetically from chemical processes.

• Ketone-based solvents: Ketones, such as acetone and methyl ethyl ketone (MEK), are chemical compounds that contain the ketone functional group. They can be produced synthetically from various chemical processes.

Among the main properties that solvents must have been:

• Ability to dissolve the resin.

• Easy evaporation and/or absorption.

• Good adhesion.

• That it is compatible with all the elements involved in the process.

• That its formulation complies with environmental preservation measures.

A key factor to consider is that evaporation should not be too fast or too slow. The formulation of an ink or varnish requires a balance between solvents, in order to make better drying possible. Hence the importance of controlling its components, through Kart-Fisher analysis or chromatography for composition identification. If you do not know how the ink you use is formulated, ask your supplier to share the technical sheet with you.

If you have concerns about this and need to determine which solvent best suits your process, it is best to do a press characterization, the result you will obtain will be even greater, since you not only define the type of solvent, but you will standardize all of them. the intervening variables within the process.