Abstract: A glass includes, as represented by mole percentage based on the following oxides, from 56 to 72% of SiO2, from 3 to 20% of B2O3, from 8 to 20% of Al2O3, from 8 to 25% of Na2O, from 0 to 5% of K2O, from 0 to 15% of MgO, from 0 to 5% of CaO, from 0 to 3% of SrO, from 0 to 3% of BaO, and from 0.1 to 8% of ZrO2. The glass contains substantially no Li2O.

Abstract: An object of the present invention is to provide a glass for chemical strengthening which is capable of improving strength as compared with an ordinary soda lime silicate glass even when the same chemical strengthening treatment as that in a conventional process is applied and has good devitrification characteristics, a chemically strengthened glass using the glass for chemical strengthening, and a method for producing the chemically strengthened glass. The present invention provides a glass for chemical strengthening having a specific glass composition described in the present specification.

Abstract: A chemically strengthened glass contains, as expressed by mass percentage based on oxides, 60% to 75% of SiO2, 3% to 9% of Al2O3, 2% to 10% of MgO, 3% to 10% of CaO, 10% to 18% of Na2O, at most 4% of K2O, 0% to 3% of ZrO2, 0% to 0.3% of TiO2, and 0.02% to 0.4% of SO3. It has a temperature T2 at which a viscosity of a glass melt is 100 dPa·sec of 1530° C. or lower. In a chemically strengthened main surface thereof, it has a depth of a compressive stress layer of 8 ?m or more and a surface compressive stress of 500 MPa or more.

Abstract: A glass is a glass sheet containing, as expressed by mass percentage based on oxides, 63 to 75% of SiO2, 3 to 12% of Al2O3, 3 to 10% of MgO, 0.5 to 10% of CaO, 0 to 3% of SrO, 0 to 3% of BaO, 10 to 18% of Na2O, 0 to 8% of K2O, 0 to 3% of ZrO2, and 0.005 to 0.25% of Fe2O3. The glass has a temperature (T2) at which a viscosity thereof reaches 102 dPa·s of 1525° C. or lower. In the glass, R2O/Al2O3 is 2.0 or more and 4.6 or less (in the formula, the R2O is Na2O+K2O).

Abstract: A glass for chemical strengthening is a glass plate. The glass plate includes, as represented by mass percentage based on the following oxides, 65 to 72% of SiO2, 3.4 to 8.6% of Al2O3, 3.3 to 6% of MgO, 6.5 to 9% of CaO, 13 to 16% of Na2O, 0 to 1% of K2O, 0 to 0.2% of TiO2, 0.01 to 0.15% of Fe2O3 and 0.02 to 0.4% of SO3. In the glass plate, (Na2O+K2O)/Al2O3 is 1.8 to 5.

Abstract: A glass for chemical tempering is provided. The glass contains as represented by mole percentage based on the following oxides, from 61 to 77% of SiO2, from 11 to 18% of Al2O3, from 3 to 15% of MgO, from 0 to 0.5% of CaO, from 0 to 4% of ZrO2, from 8 to 18% of Na2O and from 0 to 1.9% of K2O; wherein an R value calculated by the following formula by using contents of the respective components, is at least 0.66: R=0.029×SiO2+0.021×Al2O3+0.016×MgO?0.004×CaO+0.016×ZrO2+0.029×Na2O+0×K2O?2.

Abstract: A process for producing a plate glass for a display device having a thickness of at most 1.5 mm by a float process, wherein the plate glass comprises, as represented by mole percentage based on the following oxides, from 67 to 75% of SiO2, from 0 to 4% of Al2O3, from 7 to 15% of Na2O, from 1 to 9% of K2O, from 6 to 14% of MgO and from 0 to 1.5% of ZrO2, has a total content of SiO2 and Al2O3 of from 71 to 75%, has a total content Na2O+K2O of Na2O and K2O of from 12 to 20%, and has a content of CaO of less than 1% if contained.

Abstract: To provide glass to be used for chemically tempered glass, of which the strength is less likely to be reduced even when indentations are formed thereon. Glass for chemical tempering, which comprises, as represented by mole percentage based on oxides, from 62 to 68% of SiO2, from 6 to 12% of Al2O3, from 7 to 13% of MgO, from 9 to 17% of Na2O, and from 0 to 7% of K2O, wherein the difference obtained by subtracting the content of Al2O3 from the total content of Na2O and K2O is less than 10%, and when ZrO2 is contained, its content is at most 0.8%. Chemically tempered glass obtained by chemically tempering such glass for chemical tempering. Such chemically tempered glass has a compressive stress layer formed on the glass surface, which has a thickness of at least 30 ?m and a surface compressive stress of at least 550 MPa.

Abstract: To provide a method for producing chemically tempered glass, whereby frequency of replacement of the molten salt can be reduced. A method for producing chemically tempered glass, which comprises repeating ion exchange treatment of immersing glass in a molten salt, wherein the glass comprises, as represented by mole percentage, from 61 to 77% of SiO2, from 1 to 18% of Al2O3, from 3 to 15% of MgO, from 0 to 5% of CaO, from 0 to 4% of ZrO2, from 8 to 18% of Na2O and from 0 to 6% of K2O; SiO2+Al2O3 is from 65 to 85%; MgO+CaO is from 3 to 15%; and R calculated by the following formula by using contents of the respective components, is at least 0.66: R=0.029×SiO2+0.021×Al2O3+0.016×MgO?0.004×CaO+0.016×ZrO2+0.029×Na2O+0×K2O?2.

Abstract: There are provided a method for measuring strength of a chemically strengthened glass, that reflects the state of actual drop fracture more appropriately, and can reproduce slow cracking in the chemically strengthened glass, a method for reproducing cracking of a chemically strengthened glass, and a method for producing a chemically strengthened glass. Load is applied to an indenter having a tip formed into a sharp shape having a minimum angle ?min of cross-section of less than 120°, the indenter is pushed into a chemically strengthened glass under a static load condition such that the tip is vertical to a surface of the chemically strengthened glass, and the load when the chemically strengthened glass cracks is measured.

Abstract: To provide chemically tempered glass which is less likely to break even if scratched. Chemically tempered glass, which comprises, as represented by mole percentage based on the following oxides, from 56 to 72% of SiO2, from 8 to 20% of Al2O3, from 9 to 25% of Na2O, from 0 to 2% of K2O, and from 0 to 15% of MgO, and which has a surface compressive stress of at least 900 MPa and an internal tensile stress of at most 30 MPa. Glass for chemical tempering, which comprises, as represented by mole percentage based on the following oxides, from 56 to 69% of SiO2, from 8 to 16% of Al2O3, from 9 to 22% of Na2O, from 0 to 1% of K2O, from 5.5 to 14% of MgO, from 0 to 2% of ZrO2, and from 0 to 6% of B2O3.

Abstract: To provide a glass plate for display devices wherein without carrying out a post treatment, the depth of a compression stress layer is increased, while the surface compression stress is prevented from being excess only by chemical tempering. A glass plate for display devices, which is obtained by chemically tempering a glass plate comprising, as represented by mol % based on the following oxides, from 50 to 74% of SiO2, from 1 to 10% of Al2O3, from 6 to 14% of Na2O, from 3 to 15% of K2O, from 2 to 15% of MgO, from 0 to 10% of CaO and from 0 to 5% of ZrO2, wherein the total content of SiO2 and Al2O3 is at most 75%, the total content of Na2O and K2O, i.e. Na2O+K2O, is from 12 to 25%, and the total content of MgO and CaO, i.e. MgO+CaO, is from 7 to 15%.

Abstract: The present invention provides a method for producing a chemically strengthened glass for a display device, which is capable of suppressing generation of concave defects. The present invention relates to a method for producing a chemically strengthened glass substrate for a display device, in which a calcium concentration in a cleaning liquid used in a final cleaning step before a chemical strengthening step is 5 ppm or less.

Abstract: To provide a plasma display device whereby it is possible to improve the image quality and at the same time to reduce warpage of a thin cover glass plate having a large area. A plasma display device 10 is provided which comprises a plasma display panel 20 provided with glass substrates 21, 22, and a cover glass plate 30 bonded to the display side of the plasma display panel 20, wherein the cover glass plate 30 has a diagonal length of at least 81 cm and a thickness of at most 1.5 mm, and the average thermal expansion coefficient of the cover glass plate 30 is from 80 to 120% of the average thermal expansion coefficient of the glass substrates 21, 22 within a range of from 50 to 350° C.

Abstract: To provide glass to be used for chemically tempered glass which is hardly broken even when flawed. Glass for chemical tempering, which comprises, as represented by mole percentage based on the following oxides, from 65 to 85% of SiO2, from 3 to 15% of Al2O3, from 5 to 15% of Na2O, from 0 and less than 2% of K2O, from 0 to 15% of MgO and from 0 to 1% of ZrO2, and has a total content Si02+Al2O3 of SiO2 and Al2O3 of at most 88%.

Abstract: To provide a process for producing a chemically tempered glass whereby it is possible to increase the surface compressive stress. A process for producing a chemically tempered glass, which comprises holding a glass at a temperature of at least the strain point minus 40° C. and at most the strain point plus 70° C. for at least 30 minutes for heat treatment, and thereafter, immersing it in a molten salt for ion exchange without allowing the temperature to exceed the strain point plus 70° C.

Abstract: To provide glass to be used for chemically tempered glass which is hardly broken even when flawed. Glass for chemical tempering, which comprises, as represented by mole percentage based on the following oxides, from 65 to 85% of SiO2, from 3 to 15% of Al2O3, from 5 to 15% of Na2O, from 0 and less than 2% of K2O, from 0 to 15% of MgO and from 0 to 1% of ZrO2, and has a total content SiO2+Al2O3 of SiO2 and Al2O3 of at most 88%.

Abstract: There are provided a method for measuring strength of a chemically strengthened glass, that reflects the state of actual drop fracture more appropriately, and can reproduce slow cracking in the chemically strengthened glass, a method for reproducing cracking of a chemically strengthened glass, and a method for producing a chemically strengthened glass. Load is applied to an indenter having a tip formed into a sharp shape having a minimum angle ?min of cross-section of less than 120° , the indenter is pushed into a chemically strengthened glass under a static load condition such that the tip is vertical to a surface of the chemically strengthened glass, and the load when the chemically strengthened glass cracks is measured.

Abstract: To provide glass to be used for chemically tempered glass which is hardly broken even when flawed. Glass for chemical tempering, which comprises, as represented by mole percentage based on the following oxides, from 65 to 85% of SiO2, from 3 to 15% of Al2O3, from 5 to 15% of Na2O, from 0 and less than 2% of K2O, from 0 to 15% of MgO and from 0 to 1% of ZrO2, and has a total content SiO2+Al2O3 of SiO2 and Al2O3 of at most 88%.

Abstract: Glass comprising, as represented by mole percentage based on the following oxides, from 50 to 75% of SiO2, from 1 to 15% of Al2O3, from 6 to 21% of Na2O, from 0 to 15% of K2O, from 0 to 15% of MgO, from 0 to 20% of CaO, from 0 to 21% of ?RO (wherein R is Mg, Ca, Sr, Ba and/or Zn), from 0 to 5% of ZrO2, from 1.5 to 6% of Fe2O3, and from 0.1 to 1% of Co3O4.