Method of using amorphous precipitated silica parting material for shaping glass sheet doublets
AssigneePPG Industries, Inc.
InventorsRandy R. Kadunce, Paul W. Bush, Pamela L. Martino
Life of this patent
Estimating the term…
Abstract
The number of bent laminated glass windshields having bull's-eyes that adversely affect its optical properties is reduced by using amorphous precipitated silica particles such as is used as flatting agents for paints, as a parting material between a pair of glass sheets during bending. The particles form relatively soft agglomerates that are milled and classified to produce a narrow distribution of particle sizes as compared to the distribution found in untreated silica, such as diatomaceous earths previously used as a parting material.
Claims18
In a method of simultaneously bending a pair of glass sheets wherein said sheets are supported in overlaying relation, heated to a temperature at which said sheets are capable of being deformed and simultaneously shaping said sheets, the improvement comprising:
- interposing a parting material consisting essentially of amorphous precipitated silica particles between said glass sheets prior to said simultaneous bending.
In a method of simultaneously bending a plurality of glass sheets, said method including the steps of supporting a pair of glass sheets in overlying relation, heating the sheets to a temperature at which said sheets are capable of being deformed and simultaneously shaping said sheets, the improvement comprising the step of:
- interposing a parting material between said glass sheets prior to said simultaneous shaping step wherein said parting material consists essentially of amorphous precipitated silica particles which particles are in the form of agglomerates of siliceous material that are of lower hardness than untreated silica and are susceptible of breaking down into smaller particles when compressed.
Dependencies are inferred from the claim text.