CPC C03B 23/0252 (2013.01) [C03C 3/087 (2013.01); C03C 3/091 (2013.01); C03C 27/10 (2013.01); C03B 23/0258 (2013.01); C03C 2201/10 (2013.01); C03C 2201/50 (2013.01)] | 8 Claims |
1. A process for forming a curved glass laminate article comprising:
placing an outer region of a first sheet of glass material into contact with a support surface of a shaping frame, the shaping frame defining an open central cavity surrounded at least in part by the support surface, wherein the first sheet of glass material has a first average thickness, T1, and is formed from a first glass composition;
placing a second sheet of glass material on top of the first sheet of glass material, wherein the first sheet of glass material and the second sheet of glass material are both supported by the shaping frame, wherein the second sheet of glass material has a second average thickness, T2, and is formed from a second glass composition different from the first glass composition; and
heating the first sheet of glass material and the second sheet of glass material together to a forming temperature above glass transition temperatures of both the first glass composition and the second glass composition while supported by the shaping frame such that central regions of the first and second sheets of glass material deform downward into the open central cavity of the shaping frame, wherein the first sheet of glass material and the second sheet of glass material gravity sag at the same rate so that there are no bath tub shape mismatch defects after the gravity sagging near the edges of the first sheet of glass material;
wherein T2 is greater than T1,
wherein a viscosity of the first glass composition at the forming temperature, V1, is greater than a viscosity of the second glass composition at the forming temperature, V2,
wherein 3.8≤T2/T1≤6.0,
wherein T1 is between 0.3 mm and 1 mm, and
wherein V1/V2>2
wherein a polymer interlayer is located between the first glass layer and the second glass layer.
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