Method for producing laminated glazing without enamel sticking to the back-glass
A process for manufacturing a laminated glazing that includes at least a first glass sheet and a second glass sheet, includes printing a face of the first glass sheet intended to be oriented toward the second glass sheet with a liquid enamel which is dried at a temperature not exceeding 400° C., then bending the first and second glass sheets together in contact with one another in their relative position of destination in the laminated glazing, by heating at a softening temperature of the glass, wherein the liquid enamel is an aqueous silicate paint including a refractory powder of pigments and a silicate binder powder, in the absence of glass frit, and wherein a weight ratio of pigments to silicates is greater than 1.
1. A process for manufacturing a laminated glazing comprising at least a first glass sheet and a second glass sheet, the process comprising:
printing a face of the first glass sheet intended to be oriented toward the second glass sheet with a liquid enamel which is dried at a temperature not exceeding 400° C., then
bending the first and second glass sheets together in contact with one another in their relative position of destination in the laminated glazing, by heating at a softening temperature of the glass,
wherein the liquid enamel is an aqueous silicate paint comprising a mineral powder made of a refractory powder of pigments and a silicate binder powder, in the absence of glass frit, wherein the silicate binder powder consists of all solid constituents of a solid content of the mineral powder other than CuO, Fe 2 O 3 , and MnO 2 , wherein the pigments comprise at least one of Fe 2 O 3 , CuO and MnO 2 , and wherein a weight ratio of the powder of pigments to the silicate binder powder is greater than 1.
2. The process as claimed in claim 1 , wherein a liquid fraction of the paint comprises at least 80% by weight of (a) water and optionally both (b) at least one organic solvent and one or more additives.
3. The process as claimed in claim 2 , wherein the one or more additives include a thickener, a surfactant or both.
4. The process as claimed in claim 1 wherein the paint comprises from 15% to 50% by weight of organic fraction.
5. The process as claimed in claim 1 , wherein the pigments comprise Fe 2 O 3 , CuO and MnO 2.
6. The process as claimed in claim 1 , wherein the printing of the first glass sheet is carried out by screenprinting.
7. The process as claimed in claim 1 , wherein the liquid enamel is dried at a temperature not exceeding 350° C.
8. The process as claimed in claim 1 , wherein the glass sheets are bent by heating at a temperature at least equal to 600° C.for at least 5 min.
9. The process as claimed in claim 1 , wherein the glass sheets are bent by gravity sagging.
10. The process as claimed in claim 1 , wherein the pigments comprise MnO 2.