As a printing ink manufacturer with engineering industry partners, Marabu has extensive expertise in UV LED technology. This printing method offers a variety of advantages, especially for glass substrates.
New impetus thanks to UV LED curing technology
UV LED curing for screen printing has made great inroads. Printing system engineers and ink manufacturers are increasingly using this pioneering technology. UV LED curing eliminates the need for a warm-up period, saving time.
Another benefit is the faster print speed, and therefore higher throughput, as there is no need for a sleep mode when the printer is paused or when changing print jobs. In addition, UV LED lamps have a much longer life than conventional UV tube lamps.
The biggest advantage however is the wavelength of the light. The LED units operate in the UV A band, so no ozone is emitted. An air extraction system for the production area is therefore not necessary. Together, these factors result in significantly lower electricity consumption and significantly reduced costs. As a result, there is a quick payback of the initial down payment. Overall, LED technology leads to more sustainable business operations and is an attractive alternative to conventional UV-cured printing.
Growing number of UV LED curable inks on the market
To take full advantage of the benefits of UV LED curing, inks must be formulated to match its attributes. Marabu, the ink manufacturer headquartered in southwestern Germany, has made a name for itself in this field. The Marabu portfolio includes ranges of premium quality inks, especially for glass substrates.
“UV LED curable inks, such as Marabu’s Ultra Glass LEDGL range, contain photoinitiators,” said Pascal Iffland, key account manager for packaging at Marabu. These absorb the light in the UV A band and ensure full curing at the speed required for the corresponding print jobs.
In the printing industry, wavelengths between 385nm and 395nm have proven to be ideal, and Marabu’s inks have been developed accordingly. Also, unlike ceramic thermoplastic inks, UV and UV LED screen printing inks do not need to be heated inside the screen. The use of polyester fabric and the smaller particle size of the ink raw materials enable the printing of extremely fine detail. As a result, large images and sharp details can be created.
UV LED curable inks produce an abrasion resistant film that adheres firmly to the substrate. They do not require additional coating unless it is to deliberately produce a particular look and feel. And compared to ceramic thermoplastic baking inks, LED UV hardeners do not require oven drying and therefore consume much less energy. Industry experts consider a 56% reduction possible. In addition, the oven itself is not needed in the production area, which saves space.
UV LED curable printing is taking the glass decoration world by storm
The UV LED process has been successfully used to decorate plastics for many years. Beginning about five years ago, the process was applied to glass. Glass containers for personal care items should avoid contaminating their contents in any way.
For the decoration of cylindrical containers, such as drinking glasses, priority is given to the dishwasher. UV LED screen printing meets both requirements and offers other advantages. Inks printed directly onto glass items, such as beverage bottles, have greater color fastness and brilliance, communicating improved quality and gaining a competitive advantage over conventional labels.
In association with glass manufacturers, Marabu refines ink formulations for specific use cases. Printing system manufacturers are also considering how best to create decorations on certain shapes and materials.
These collaborative activities resulted in Ultra Glass LEDGL. This UV LED curable screen printing ink combines excellent initial adhesion with exceptional opacity, gloss and responsiveness. The product range includes gloss and gloss colors and high opacity tones for dark substrates.
Marabu offers its customers the widest choice of high opacity ink colors on the market. With appropriate printing systems it is also possible to perform pinning: this is a form of hardening allowing 360 degree decoration of cylindrical items, such as tubes and bottles. Depending on the exact scenario, the substrate may require pre-treatment.
Ultra Glass LEDGL is a two-component system that requires the addition of an adhesion promoter (bonding agent) for effective use. It also allows flexibility in the printing method chosen, as LEDGL is a dual cured screen printing ink. Following its successful deployment by customers and in response to growing demand, Marabu is expanding the range of LEDGL colors available.
The company will soon launch a bronze binder for special metallic colors. Additionally, Marabu is cooperating with an engineering partner to test a suitable primer for UV LED curing. This would allow subsequent decoration of glass substrates with hot stamping foil.
UV LED screen printing has been used successfully to decorate plastics for many years. It was mainly used for personal care items, for example tubes and bottles which have to meet strict requirements. Recently, another use case has caught the eye, namely metal. Glass inks also provide very good adhesion to this substrate. As a result, UV LED curing screen printing systems are already being deployed to directly print metal packaging.
Iffland is confident: “This technology is sure to be quickly adopted in other fields of application where it can play its strengths.”