METHOD OF INCREASING RESISTANCE TO INTRUSION THROUGH GLAZED OPENING AND WINDOW GLASS HAVING RESISTANCE INCREASING TO INTRUSION

摘要

PURPOSE: To prevent the penetration of a glazed opening by using a laminate glass obtained by bonding an original glass plate subjected to a chemical tempering treatment to a thin glass sheet cut so as to have substantially the same form dimension as the original glass plate with the aid of at least one intermediate layer of thermoplastic material and firmly fixing them. CONSTITUTION: A curved side glass plate 2 is removed from an automobile. This is subjected to a chemical tempering treatment by being dipped in a potassium nitrate bath kept at a temperature of 450 deg.C for 24 hours. A glass sheet of 1.2 mm thickness is cut in the dimension of the original glass plate 2 to form a thin glass sheet 3, the edge thereof is ground, and the thin glass sheet 3 is also chemically tempered in the same manner as the sheet 2. A sandwich consisting of the original glass plate 2 and the thin glass sheet 3 separated by an insert layer 4 of polyvinyl butyral is bonded at 100-150 deg.C to form a layered window glass 1. This window glass 1 has a thickness of 6.2 mm in total, and this can be returned to the seat of the automobile.