VACUUM INSULATING GLASS (VIG) UNIT WITH LEAD-FREE DUAL-FRIT EDGE SEALS AND/OR METHODS OF MAKING THE SAME

摘要

Certain example embodiments of this invention relate to vacuum insulating glass (VIG) units having improved seals made using two different frit-based edge seal materials, and/or methods of making the same. In certain example embodiments, a first frit material is applied around peripheral edges of first and second glass substrates. The first frit material, which may be bismuth-based in certain example embodiments, is fired with a heat treatment (e.g., thermal tempering) process. A second frit material, which may be VBZ-based in certain example embodiments, is applied and at least partially overlaps with the fired first frit material. The first frit material acts as a primer, and the second frit material helps seal together the VIG unit. The second frit material is fired at a significantly lower temperature that enables the glass to retain the temper or other strength imparted by the heat treatment.

主权项

1. A method of making a vacuum insulating glass (VIG) window unit comprising first and second glass substrates, each said substrate having first and second major surfaces, the method comprising:
applying a first lead-free frit material around perimeter edges of the first major surfaces of the first and second substrates; heat treating the first and second substrates with the first frit material thereon, the first and second substrates reaching a first peak temperature; following said heat treatment, applying a second lead-free frit material on the first and/or second substrate(s) such that, for each substrate on which the second frit material is applied, the second frit material at least partially overlaps the first frit material on the respective substrate around peripheral edges thereof, the first and second frit materials having different compositions; positioning a plurality of spacers on the first surface of the first substrate; bringing together the first and second substrates such that the first major surfaces of the first and second substrates face one another, and such that a cavity is defined therebetween, in making a VIG unit subassembly; heating the subassembly in order to melt the second frit material and wet the first frit material, the heating being performed such that the first and second substrates reach a second peak temperature that is no higher than 400 degrees C. and that is at least 150 degrees C. lower than the first peak temperature; following said heating of the subassembly, cooling and/or allowing the subassembly to cool, in forming an edge seal between the first and second substrates; evacuating the cavity to a pressure less than atmospheric via a pump-out port; and sealing the pump-out port in making the VIG unit.