Vacuum bag, apparatus and process for the production of laminated glass elements

A lamination process for producing a laminated glass element (2), comprising the steps of:

• pre-assembling the laminated glass element (2) by superimposing glass panes (8′, 8″) with one sheet of polymeric material (9) interposed therebetween to form a pre-assembled laminated glass element (2) comprising an upper pane (8′) and a lower pane (8″);
• providing a vacuum bag (1) comprising an upper portion (3) and a lower portion (4) having different elasticities, the upper portion being more resilient and the lower portion being less resilient;
• introducing the pre-assembled laminated glass element (2) into said vacuum bag (1) so that the more resilient upper portion (3) of the vacuum bag (1) will be placed above said upper pane (1), and the less resilient lower portion (4) of the vacuum bag (1) will be placed below said lower pane (8″);
• connecting together said upper and lower portions (3, 4) of the vacuum bag having different elasticities at a base of a vertical perimeter edge (8′c, 8″c) of the glass panes (8′, 8″) being laminated;
• hermetically closing the vacuum bag (1);
• connecting the vacuum bag to a vacuum generating system;
• generating vacuum inside the vacuum bag (1) within a lamination chamber to cause the upper portion (3) of said vacuum bag to adhere (1) to the upper surface (8′a) of the upper pane (8′) and to perimetric side surfaces (8′c, 8″c) of said upper and lower panes (8′, 8″);
• and
• introducing the vacuum bag into the lamination chamber and carrying out a heating cycle for lamination, thus providing the laminated glass element (2) with no leakage of bonding material from perimeter edges (8′c, 8″c) of the upper and lower panes (8′, 8″).