When printing on glass a clean, dust and grease-free surface is always essential. Therefore, always clean glass materials thoroughly prior to printing.

Prints on sheet glass generally have a good mechanical resistance (adhesion and scratch resistance). However, it is much more difficult to achieve a high water resistance of the prints. Depending on requirements, there are different options for processing UVGS.

There are four different options for adjusting and processing UVGS inks:

 

• Option 1: Rapid achievement of very high resistances.

Addition of 5% adhesion promoter UVGS/HS + oven curing 140°C/20 Min. after UV-curing.

UVGS ink cured this way will be resistant to condensation as well as direct water contact for longer periods. Mechanical resistance of the wet ink film will be slightly reduced, however, will reform quickly and completely after drying.

Application: Furniture industry including bathroom furniture. Technical applications.

 

• Option 2: Mechanical processing of the glass after printing.

Addition of 5% adhesion promoter UVGS/HS. Just UV-curing (without additional oven curing).

Initially the just cured ink film will be quite flexible. Therefore, the ink film will not chip if the sheet glass is cut or grinded immediately after printing. There will be a good mechanical resistance and, in most cases, sufficient water resistance. However, it will take approximately 4 weeks, before the final high resistance values will be achieved.

Application: Furniture industry including bathroom furniture. Technical applications.

 

• Option 3:

Rapid achievement of very high resistances without oven curing.

Addition of 5% adhesion promoter UVGS/HS, 3% hardener UVGS/HF. Just UV-curing.

If oven-curing is not possible, in addition to adhesion promoter UVGS/HS it is possible to further add hardener UVGS/HF (3%). After UV-curing the printed ink film will further cure chemically-reactive at room temperature (>20°C). The dried ink film will show good resistances after 24 h, however, final properties (hardness) will only be achieved after 72 h.

Application: Furniture industry including bathroom furniture. Technical applications.

 

• Option 4: Water resistance and condensation resistance not required.

No addition of adhesion promoter or hardener. Just UV-curing. Hard and mechanical resistant ink film immediately after UV-curing.

Application: Furniture industry (excluding bathroom furniture). General glass decoration in dry environments.

• Although UVGS inks can be processed as 1-component ink without addition of adhesion promoter, they are generally processed as 2-component ink with adhesion promoter.

• The cured ink film exhibits very high mechanical abrasion resistance and good chemical resistance. When processed with adhesion promoter UVGS/HS prints also show a good water resistance.

• Due to the binders screen printing inks UVGS are not suitable for outdoor applications.

• Note on multi-layer printing: The very high level of cross-linkage of the cured ink film of UVGS inks may affect intermediate adhesion. In some cases, this can be avoided by reducing the UV curing energy when curing the lower ink layer(s). However, this must be confirmed carrying out corresponding pre-trials. At the same time, you have to check if the prints still meet the resistance requirements.

• Note on water resistance:

Water resistant adhesion on glass is achieved by a complex interaction of the components and therefore also depends on the type of glass material. If the required resistances can be achieved has to be confirmed by carrying out accurate pre-trials. Any change or deviation of the processing parameter may influence the result, especially in reference to water resistance.