EuroWire September 2024

Technology News

The secret world of industrial ink

binding agent and the colourant that remains after the solvent has evaporated. Traditionally, both the solvent and the binding agent have been oil-based, which presents a challenge to ink manufacturers. Leibinger is now able to produce an ink that is around 85 per cent bio-based, reducing the impact on the world’s resources. Ink properties reflect specific customer needs Many applications require a printed number or barcode to remain permanently visible, but some customers need inks that can be removed when required. Inks are therefore created with varying levels of permanence or washability. For example, when a recyclable glass bottle is refilled, a new expiration date needs to be applied in place of the old one, which is typically removed via a caustic solution in the recycling plant. However, because such bottles frequently get wet (such as from condensation when removed from the fridge), the ink must be permanent enough not to be erased by water alone. Plastic recyclable bottles present a different challenge: they are not refilled, but the expiration date must still be erased to prevent the ink adding a grey tinge to the recycled material. However, some markings are very temporary. In car manufacturing, rolls of aluminium sheets are usually marked with a batch number. Once those sheets have been shaped into panels for the vehicle, the code must easily removable. produce their own ink Some printer companies have to buy their ink from a third party, which provides a “certificate of analysis” that proves the chemical constitution of the ink. As a manufacturer of both industrial inkjet printers and industrial printer ink, Leibinger can dedicate resources to testing different inks in different printers, helping customers to find a combination that allows them to print more accurately, efficiently and sustainably. Leibinger offers machines that operate at different speeds, with a range of features and price points, and combines them with an ink formulation that will give the best result on the specific substrate – metal, glass, cardboard or other materials. Many printer manufacturers cannot

Thousands of different inks are used by different industries around the world, especially in CIJ (continuous inkjet) industrial printing, applying batch numbers and codes to products and packaging. Leibinger produces both printers and the ink used in them, and so has particular insight into this universal substance. Dr Thomas Paul, ink expert at Leibinger Group, revealed some interesting facts. Security UV ink has the same ingredient as washing powder UV-readable ink can be used as a security feature, when hidden marks or codes are added to prove a product is genuine. However, the colourant that shows up under UV light is commonly available, and is a key ingredient in most laundry detergents, because the blueish hue helps to counteract the gradual yellowing of clothes, keeping them apparently whiter. More advanced security inks combine different colours to make them less easy to recreate. The harder the PVC, the easier the printing More than 40mn tonnes of PVC (polyvinyl chloride) are produced each year. In its pure form it is quite brittle, so plasticisers are often added to make it more flexible. Rigid plastic pipes, for example, contain less plasticiser than the more flexible PVC used for cable sheathing. However, while ink adheres well onto PVC molecules, it will not stick to plasticiser molecules, so printing onto cables is challenging. Leibinger engineers have produced alternative ink formulations that adhere more readily to plasticiser molecules, to solve this problem. “Green” ink is harder to produce – but worth the effort To assess the environmental footprint of ink, we need to first look at its key components. Around 80 per cent of the ink consists of solvent, as the ink has to be ultra-fast drying in industrial and packaging coding applications. Most of the remaining material is the

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Leibinger produces both industrial inkjet printers and industrial printer ink

Paul Leibinger GmbH & Co KG www.leibinger-group.com

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September 2024