Strengthening of thin-walled, light glass containers

摘要

Thin-walled, light glass containers formed by the press and blow process may be strengthened by (1) EXPOSING THE INTERNAL SURFACE OF SAID CONTAINERS TO THE ACTION OF AN AGENT CAPABLE OF DECREASING THE AMOUNT OF EXTRACTABLE ALKALI FROM SAID SURFACE AT AN ELEVATED TEMPERATURE IMMEDIATELY AFTER THE BLOWING PROCESS BUT BEFORE THE ANNEALING PROCESS; (2) PASSING THE CONTAINERS THROUGH THE ANNEALING STATION; AND (3) SUBJECTING THE EXTERNAL AND INTERNAL SURFACES OF SAID GLASS CONTAINERS TO A TREATMENT OF EXCHANGING SODIUM IONS IN THE SURFACE PORTION WITH POTASSIUM IONS TO FORM A COMPRESSIVE STRESS LAYER IN SAID SURFACE PORTION.