Digitally Printing on Glass - The Sol Gel Technique

We know that any form of printing on Glass has provided challenges in the past, but that in Industrial applications it was one of the areas where Digital was being used often.

He explained the Sol-Gel-Technique,  this is a very special system to put a thin coatings mainly on glass and similar materials. The name reflects the technique. First of all a „SOL“ has to be produced, the sol-gel process is a method for producing solid materials from small molecules. The basic system starts with a silica  (TEOS tetraorthosilicat) from which with a condensation- and hydrolisation-process the „SOL“ is produced. To get better properties for the later coating process normally ORganic MOdified Silica is added to the „SOL“ before the condensation- and hydrolisation-process. With this ORganic MOdificated „SOL“ now coatings can be produced up to an thickness of 2 µm.

Finally the dye and/or pigments, solvents and other components can be added and this is now a „SOL“ which may be used for spray-coating or as an ink for digital printing. The next step after the „SOL“ is the „GEL“. This means the coating on the surface. After the solvents have been evaporated there will be a dry coating on the surface. The coating is really dry – not sticky- and can then be handled. At this stage the coating/picture is not solvent resistant an the coating can be washed off. To get solvent resistant coatings the „GEL“ has now be backed. The higher the the backing temperature is the harder the final product will be. „Normal“ inks with organic dyes or pigments have here a limitation of max. 200°C because of the organic dyes/pigments. White inks may be heated up to 800°C and more. The coating will then become a glass like system and can be printed directly onto Glass.

Professor Ferdinand Trier, Munich University of Applied Sciences has a number of Free White Papers on the subject of Digitally printing on Glass and will be speaking at our InPrint/IMI showcase conference on June 24th and at InPrint in November.

If you are interested in either the White paper or attending the seminar, please email me at Frazer.chesterman@mackbrooks.com