Enamel printing process for a laminated glazing having functional layers

1. A process for the manufacture of a laminated glass for a motor vehicle comprising at least a first glass sheet in contact with an exterior of the motor vehicle, a second glass sheet in contact with an interior of the motor vehicle and a thermoplastic interlayer positioned between the first and second glass sheets, at least one of said first and second glass sheets being provided with a stack of thin layers comprising a plurality of functional layers sensitive to scratches, said process comprising the following stages carried out in the following order:

a. depositing the stack of thin layers on a face of the first or of the second glass sheet;

b. positioning of the face coated with the stack of thin layers resting on a support so that the stack of thin layers is in contact with the support;

c. depositing, by spraying or brushing, a liquid enamel on a zone of an uncoated face of the first or the second glass sheet used in stage a), said liquid enamel having a composition that has a viscosity of less than 10 Pa . s, said liquid enamel extending up to a peripheral edge of said first or second glass sheet used in stage a);

d. bending the first and second glass sheets by heating the first and second glass sheets to temperatures of between 500 and 650° C., wherein no stage of drying and of precuring is carried out before stage d), wherein said liquid enamel is dried and cured during said stage d) of bending;

e. installing the thermoplastic interlayer between the first and second glass sheets to form an assembly of the first and second glass sheets and the thermoplastic interlayer, so that the face coated with the stack of thin layers is turned toward said thermoplastic interlayer;

f. degassing the assembly under vacuum, then

g. sealing and autoclaving the assembly.

2. The process as claimed in claim 1 , wherein stage c) is carried out by at least one automated applicator robot provided with at least one feed head equipped with a brush and fed continuously with the enamel composition.

3. The process as claimed in claim 2 , wherein said automated applicator robot is also provided with means adapted to keep the coated face resting on the support.

4. The process as claimed in claim 1 , wherein stage c) is carried out by one or more robots provided with at least two feed heads in order to carry out simultaneously a printing of the enamel over the whole of a glazing formed by said laminated glass, each of the feed heads carrying out the deposition over a portion of the glazing.

5. The process as claimed in claim 1 , wherein the enamel deposited in stage c) is a liquid composition, a viscosity of which is between 2 and 5 Pa . s.

6. The process as claimed in claim 1 , wherein the stack of thin functional layers deposited in stage a) comprises at least one silver layer.