Introduction
Innovation is one of the key drivers of business success. In the world of printing, UV ink has emerged as a player known for its unique benefits. With faster drying time, high-quality, durable prints, and broad application capability, they stand out from other ink options.
If you’ve been searching for inks that produce brighter prints at both the individual and professional levels, UV ink could be a game-changer, helping you save time!
UV ink, in short, is a specialized ink that is a blend of certain unique materials that dries instantly when exposed to UV light. Unlike traditional inks, which absorb into the printing material, take longer to dry, and dilute the colours, resulting in lower colour vibrancy, these inks outperform conventional inks.
In this article, we will explore all about UV inks- how they work, their advantages and limitations, and more. So, read till the end to get your questions answered.
What Is UV Ink?
UV inks are specialised inks that form a solid polymer network upon exposure to UV light. They are formulated using specialized light-sensitive compounds, pigments, resins, and other additives. This unique blend gives the ink distinct properties that set it apart. Let’s discuss them in detail to better understand.
The composition of UV inks includes:
Oligomers and monomers: These resins make up the main building blocks, forming the ink’s structure. Oligomers mainly include the reactive resins and adhesive compounds. They help bind the ink to various materials, shaping the final film properties. Monomers are small molecules that control the ink characteristics. These include hardness, viscosity, elongation, and softness.
Photoinitiators: These are small molecules that react to light. Simply put, they are “trigger” chemicals that absorb UV energy and generate reactive species that initiate polymerization. UV inks are tuned to specific wavelengths for curing. Without these molecules, the instant curing upon UV light exposure is not possible.
Pigments: These are particles that give the UV ink its colour. They are fine enough to start dispersion and do not clog the printer nozzle. These pigments do not absorb and just sit at the top of the print, giving them a pop of color. UV inks are available in white, neon, and metallic colors.
Other additives are used to adjust flow, adhesion, scratch resistance, and print performance. Additionally, they help control the surface finish after applications.
How do they work?
UV inks work differently from solvent-based and other traditional inks. Water-based and solvent-based inks rely on the evaporation of their respective carriers. It takes more time. And that’s why it can smudge or smear.
When the UV printer prints ink onto the material’s surface, it does not absorb; instead, it sits on the surface. Immediately after that, the UV light source shines on the ink to cure it.
To cure UV inks, high-intensity UV light hardens inks, coatings, or adhesives in seconds. The UV energy activates the photoinitiator system. That activation starts a chain reaction that links monomers and oligomers together.
A common pathway is free-radical polymerization. UV light causes photoinitiator molecules to split, forming free radicals. These radicals react with unsaturated monomers and oligomers, building a crosslinked polymer film that holds pigment and bonds to the substrate.
Curing is a chemical conversion. That’s why most of the liquid formulation becomes part of the final solid film. In contrast, water-based and solvent-based inks rely on evaporation of a carrier, which takes more time.
Where UV Ink Is Used
UV inks, due to their advantages such as the ability to print on various substrates and an efficient printing process, are well-suited for many applications. Their application spans across commercial and industrial sectors.
UV inks can be seen used in:
- street signage
- labelling and product packing
- credit cards
- sports equipment printing
Advantages of UV Ink
Speedy printing and drying process
After the UV printer prints ink onto the substrate, the UV light exposure dries it within a few seconds. This makes the entire printing process much speedier. In this way, the inks get no time to smudge or smear, making UV printing a seamless process.
Applicable to non-porous substrates
UV inks are applicable and widely used for hard and non-porous surfaces. Compared to conventional inks, which are limited to specific substrates, UV inks can be used on a variety of substrates. These include glass, wood, tiles, cardboard, polystyrene, foil, paper, vinyl, and metal.
Odourless
Another advantage of UV inks is that they are completely odourless, unlike traditional solvent-based inks, which produce a harsh smell during printing. This is beneficial if you have a compact facility or are sharing space.
Environmentally friendly
The inks do not emit VOCs or other harmful particles in the atmosphere and are considered environmentally friendly. Also, the efficient printing and drying process saves energy.
No drying equipment needed
UV light is used to cure the UV prints. This reduces the number of prints passing through the drying tunnel or the need to use a heat press to cure prints, as done with conventional inks. The compact UV printing setup is easy to handle and reduces the costs associated with extra equipment.
Long-lasting prints
UV prints have a long lifespan, much longer than traditional solvent-based inks. They are resistant to sunlight and include compounds that make them scratch-resistant.
Limitations of UV Ink
Not applicable to textiles and clothing
Because they apply to a wide variety of materials, they are not suitable for textile and clothing materials. As these materials are soft and flexible, they bend and may crack or peel. This restricts UV printing to harder materials, not textiles or softer materials.
Higher associated costs with UV inks
The cost of UV inks is, of course, higher than that of conventional ones. The reason is the entirely different formulation involved in the UV inks. Also, prices may vary across manufacturers due to differences in UV ink quality. High-quality inks provide better adhesion, opacity, and long-lasting performance. All these factors come into play, driving up the ink costs.
How to Store UV Ink
Storing the UV ink at the right temperature and humidity conditions is vital for extended shelf life. The following are some conditions you must follow:
- Temperature: 15-35 °C (59-95°F)
- Humidity: 30-70%
If the temperature drops below 5 Celsius, the inks may crystallise. In contrast, you may also be careful that the UV ink should not be moved suddenly from a cold to a warm environment. Otherwise, condensation may occur, and moisture may appear on the ink surface. Ultimately, it will affect the inks’ printing performance.
The best way to store UV ink is to keep it in a cool, dry place with a tightly sealed lid.
How long does UV ink last?
The lifespan of UV inks can vary. It depends on the application and ambient factors. Besides, the quality of UV inks also impacts their lifespan. When used indoors, UV inks can last up to 5-7 years. Outdoor-rated UV inks, when used correctly in outdoor applications, can last 7-10 years.
Is UV Ink Safe?
It’s not entirely straightforward. Although UV inks do not produce any harmful chemicals or VOCs (Volatile organic compounds), handling UV inks requires proper clothing and ventilation. Uncured inks must not come into contact with the skin or eyes. So, it is essential to wear gloves, safety eyewear, and a mask. Maintain hygienic conditions and clean any spills frequently.
Conclusion
UV inks are undoubtedly a fast and reliable option for printing various materials. The fast-curing, UV-light-exposed process, which produces long-lasting, vibrant prints, makes them stand out. Like other inks, UV inks offer various advantages but also have some limitations. If your business involves printing on hard, non-porous materials, UV inks can meet your needs.
