What Is the Significance of Ink in Flexographic Printing?
Ink is the core component of the flexographic printing technique. Flexographic ink is an amalgamation of resins, pigments, additives, and solvents. Without utilizing the most suitable ink for your printing purpose, you will not be able to achieve the desired printed outputs. Therefore, the choice of ink from the various types of inks in flexographic printing is a major deciding factor that can change the printing results.
Furthermore, the type of ink also plays an important role in determining the print’s lead time, substrate, and quality. It should be noted that the inks are attracted to the highest dyne level. Therefore, the best ink should be of low dyne level, and the substrate should be of the highest dyne level. Therefore, one must be well-versed with the types of inks utilized in flexography along with the pinpoint knowledge of the applicability of each type.
What Are the Types of Ink in flexographic printing and Their Applicability?
Generally, flexographic printing comprises four different types of inks. The types of inks are classified into two categories:
- Volatile Inks: These inks contain a liquid solvent in the mixture, such as water or alcohol. The solvent evaporates, leaving behind the printed image on the surface.
- Energy Curable Inks: The drying process of these inks is due to the intermolecular bonding that results in the printing on the substrate.
Four common types of flexography inks fall in these two above-discussed categories. The useability, environmental implications, surface tension, and compatible substrate are different for each type of flexographic ink. Following is a brief analysis of each type of ink for flexography printing.
The water-based ink comprises water as the chief solvent. Water is added to pigments and defoamer agents to create a water-based ink. Furthermore, it also contains drying and adhesive agents. Therefore, it is best applicable to elastomer plate types.
Water-based ink has the highest surface tension. Therefore, it is viable to use for the corrugated packaging industry. In addition, this type of ink is most environmentally friendly and is preferred for this aspect. However, it has speed limitations due to higher surface tension.
Solvent-based flexography inks comprise alcohols and acetates as the solvent. These solvents are mixed with pigments. Moreover, the ratio of alcohols ranges from 80% to 90%, and the ratio of acetates is 10% to 20%. However, these ratios can be altered to obtain the required level of quality.
The core advantage of this ink is that it has lower surface tension than water-based ink. Furthermore, EPDM elastomer is recommended for solvent-based inks owing to the lower surface tension. This type of ink is best applicable for printing on shopping bags and industrial films.
The UV-based inks have prepolymers, monomers, photo-initiators, and pigments. The adhesion of this ink culminates only when it is exposed to UV light or electron beam. Moreover, UV-based inks have higher viscosity. Therefore, EPDM elastomer is generally recommended for utilizing this type of ink in flexography. It applies to the outer wrap of food packaging.
This type of ink is a mix of hydrocarbons and pigments. Moreover, soy oil is also added in some scenarios. Harsh solvents, such as naphtha or hexane, are blended in this ink. Nitrile elastomer is typically recommended. Oil-based inks are best for the publication printing industry.
The Crux: Which Type of Flexography Ink Is Best?
The choice of ink in flexography printing is a critical decision that must be taken after considering printing speed, surface tension, and substrate. All the above-discussed types of flexography inks have their pros and cons. However, you can choose the most suitable per your printing requirements.
Lastly, you can check out the different types of flexography inks at Anyflexo. We provide all types of inks for flexographic printing and can also provide customized versions.