GLASS SCREEN-PRINTING INKS FOR FUNCTIONAL DISPLAY APPLICATIONS

Displays, such as ticket machines, e-charging stations and smart-home applications, have become an integral part of everyday life. The display of various devices conveys information and serves as a design element. In the form of touch displays, many interior functions can be intuitively controlled. For example, lighting, room climate and blinds. To achieve state-of-the-art quality and performance, display manufacturers are increasingly turning to durable glass materials. With regard to scratches, abrasion and chemicals, the combination of modern glass design and electronics enables highly resistant surfaces for IT, industrial, automotive and medical devices.

For the long-term use of end devices, decorative and functional components must meet high-quality requirements and, furthermore, have a permanent reliable bond. Aesthetics and functionality often play a primary role for indoor devices. Outdoor applications pose challenges for components, such as resistance to temperature fluctuations and UV radiation. 

For these reasons, glass finishers place high demands on quality, appearance and durability. In addition, easy processing and further processing during production must be guaranteed. 

For decorative purposes, indoors and outdoors, ceramic printing inks have been used as a standard for glass finishing for many years. These are melted onto the glass surface at temperatures of often more than 600°C after application. However, ceramic inks regularly reach their limits, especially when it comes to brilliant colour shades, as well as the coating of very thin or laminated glasses. Because of this, glass finishers are increasingly turning to alternatives to this energy-intensive ink technology.

Proell’s core expertise lies in the development and production of customised chemical products for printing on glass, plastics, metals and many other substrates. The innovative solvent and water-based – as well as UV-curing screen- and pad-printing inks – are used for a wide variety of industrial and graphic applications across all industries.

Glass finishers place high demands on quality, appearance and durability

For the decoration of glass, particularly for the realisation of touch panels and backlit displays, special organic screen-printing inks for indoor and outdoor applications are available. These inks are mainly printed on the second surface of the glass panels.

Ceramic inks regularly reach their limits, especially when it comes to brilliant colour shades

The NoriGlass screen-printing inks offered for glass applications today are particularly impressive due to a variety of characteristics. NoriGlass outdoor-resistant (OR) inks are formulated without aromatic solvents and all colour shades can be formulated free of halogens. In addition to the essential property of very good long-term adhesion to the glass substrate, glass screen-printing inks also need to have very good bonding properties. This ensures a permanent adhesion to films and other components of the corresponding device. 

The different ink systems marketed under the NoriGlass brand, meet the highest demands for excellent glass adhesion and best bonding properties. This is due to their unique composition, silicone-free formulation and very high surface-free energy of the cured ink film. 

Both homogeneous transparent or semi-transparent and highly opaque colour shades are available, making it possible to realise dead-front effects and precisely adjust transmission values. Even the translucent-adjusted colour shades show an excellent ink levelling and a homogeneous surface.

Highly opaque ink layers can be achieved with a very low layer thickness – resulting in a low printing shoulder – offering advantages for optical bonding. IR-transmissive black colour shades are available for when ink layers need to guarantee high permeability to infrared (IR) radiation. These are required when the functionality of sensors are concealed behind glass, such as proximity sensors.

In terms of user-friendliness, great attention has been paid in order to ensure that the inks allow the screen to remain open for a long time. The inks prevent drying into the screen mesh – even during printing breaks. 

Organic screen-printing inks have another major advantage over ceramic inks. They require significantly lower stoving temperatures for processing. This makes them suitable for thin glass applications and use on laminated glass types. Especially in times of constantly rising energy costs, organic screen-printing inks, which can be stoved at temperatures between 120 –180°C – depending on the ink type – are likely to become increasingly attractive for processors.

The Titanium White has a very high degree of whiteness and an extremely low tendency to yellow

The NoriGlass OR ink series also offers a special feature. As a two-component system based on high-quality binders and hardener, it forms ink films with very high resistances to both chemicals and UV radiation. These properties make it suitable for outdoor applications if applied on the second surface of glass. 

Outstanding opacity can be achieved with the highly opaque colour shades NoriGlass OR 930 Titanium White and NoriGlass OR 960 Deep Black. In addition, the Titanium White has a very high degree of whiteness and an extremely low tendency to yellow.

One of the particularly remarkable features of the Deep Black is a very high electrical resistance, which means that the cured ink layer has no negative influence on touch sensors.