Abstract: Provided is an alkali-free glass substrate having a high strain point and excellent bubble count, and a method for manufacturing the alkali-free glass substrate. The method includes: a batch preparing process of preparing a raw material batch so as to obtain alkali-free glass containing, in mass %, 50 to 80% of SiO2, 15 to 30% of Al2O3, 0 to 4.5% of B2O3, 0 to 10% of MgO, 0 to 15% of CaO, 0 to 10% of SrO, 0 to 15% of BaO, 0 to 5% of ZnO, 0 to 5% of ZrO2, 0 to 5% of TiO2, 0 to 15% of P2O5 and 0 to 0.5% of SnO2 as a glass composition; a melting process of melting the prepared raw material batch; a fining process of fining the molten glass; and a forming process of forming the fined glass into a sheet shape. The raw material batch is melted such that a bubble enlarging temperature of the obtained glass is lower than a maximum temperature of the fining process.

Abstract: A manufacturing method for a glass article includes a supply step of supplying a glass raw material onto a surface of a molten glass accommodated in a melting chamber of a glass melting furnace from a supply unit mounted to a front wall of the melting chamber, and a melting step of melting the supplied glass raw material through heating with an electrode immersed in the molten glass in the melting chamber. The method also includes an outflow step of causing the molten glass to flow outside the melting chamber from an outflow port provided at a rear wall of the melting chamber, wherein 60% to 95% of an area of the surface of the molten glass in the melting chamber is covered with the glass raw material supplied in the supply step.

Abstract: A manufacturing method for a glass article includes a supply step of supplying a glass raw material onto a surface of a molten glass accommodated in a melting chamber of a glass melting furnace from a supply unit mounted to a front wall of the melting chamber, and a melting step of melting the supplied glass raw material through heating with an electrode immersed in the molten glass in the melting chamber. The method also includes an outflow step of causing the molten glass to flow outside the melting chamber from an outflow port provided at a rear wall of the melting chamber, wherein 60% to 95% of an area of the surface of the molten glass in the melting chamber is covered with the glass raw material supplied in the supply step.

Abstract: Provided is a manufacturing method for a glass article, including: a glass melting step of continuously melting glass raw materials (Gr) in a glass melting furnace (1) by heating (electric heating) through application of a current with an electrode (11) to generate a molten glass (Gm); and a forming step of forming the molten glass (Gm) into a sheet glass by a down-draw method. The glass melting step includes adjusting a water vapor amount in an atmosphere in the glass melting furnace (1) to 15 g/Nm3 or less.

Abstract: A method of manufacturing a glass sheet stably reduces a variation in a thermal shrinkage rate to 15 ppm or less. The method includes a melting step of melting, in an electric melting furnace, a glass batch prepared so as to give glass comprising 3 mass % or less of B2O3, a forming step of forming a molten glass into a sheet-shaped glass, an annealing step of annealing the sheet-shaped glass in an annealing furnace, and a cutting step of cutting the annealed sheet-shaped glass into predetermined dimensions, to thereby obtain a glass sheet having a ?-OH value of less than 0.2/mm and a thermal shrinkage rate of 15 ppm or less. The method includes measuring a thermal shrinkage rate of the glass sheet and adjusting a cooling rate of the sheet-shaped glass in the annealing step depending on variation in thermal shrinkage rate with respect to a target value.

Abstract: A glass roll includes a glass film formed by a downdraw method. The glass film is wound into a roll using a winding roller in a state in which front and back glass surfaces of the glass film formed in the forming operation are exposed, and during the winding operation, the glass film is superposed on a separable protective sheet. The protective sheet extends beyond both sides in a width direction of the glass film. The protective sheet can further be wound on an outer peripheral surface of the glass film by winding only the protective sheet from a trailing end of the glass film in a winding direction of the glass film.

Abstract: Provided is an alkali-free glass substrate having a high strain point and excellent bubble count, and a method for manufacturing the alkali-free glass substrate. The method includes: a batch preparing process of preparing a raw material batch so as to obtain alkali-free glass containing, in mass %, 50 to 80% of SiO2, 15 to 30% of Al2O3, 0 to 4.5% of B2O3, 0 to 10% of MgO, 0 to 15% of CaO, 0 to 10% of SrO, 0 to 15% of BaO, 0 to 5% of ZnO, 0 to 5% of ZrO2, 0 to 5% of TiO2, 0 to 15% of P2O5 and 0 to 0.5% of SnO2 as a glass composition; a melting process of melting the prepared raw material batch; a fining process of fining the molten glass; and a forming process of forming the fined glass into a sheet shape. The raw material batch is melted such that a bubble enlarging temperature of the obtained glass is lower than a maximum temperature of the fining process.

Abstract: A method for manufacturing an alkali-free glass substrate capable of manufacturing an alkali-free glass substrate having a higher strain point by decreasing the ?-OH value of the glass is provided. The method for manufacturing an alkali-free glass substrate is a method for continuously manufacturing a SiO2—Al2O3—RO (RO is one or more of MgO, CaO, BaO, SrO, and ZnO) based alkali-free glass substrate, which includes a step of preparing a raw material batch containing a tin compound and substantially not containing an arsenic compound or an antimony compound, a step of electric melting the prepared raw material batch in a melting furnace capable of conducting electric heating by a molybdenum electrode, and a step of forming the molten glass into a plate shape by a downdraw method.

Abstract: A technical object of the present invention is to devise a method in which minute foreign matter of a platinum group element is less liable to be generated when a Na2O-containing glass having high viscosity at high temperature is formed into a sheet shape by an overflow down-draw method. In order to achieve the above-mentioned technical object, a method of manufacturing a tempered glass sheet of the present invention includes: a melting step of melting a glass batch in a melting furnace to provide a molten glass; a fining step of fining the molten glass at a highest temperature of from 1,450° C. to 1,680° C.

Abstract: A glass roll reliably prevents a glass film from breaking from an end surface of the glass film as an origin of breakage. The glass roll is formed by winding the glass film into a roll while superposing the glass film on a protective sheet. The glass film is formed by an overflow downdraw method to have a thickness of 1 ?m or more and 200 ?m or less, and has each end surface in a width direction formed as a cut surface cut by laser splitting.

Abstract: A glass roll includes a glass film formed by a downdraw method. The glass film is wound into a roll using a winding roller in a state in which front and back glass surfaces of the glass film formed in the forming operation are exposed, and during the winding operation, the glass film is superposed on a separable protective sheet. The protective sheet extends beyond both sides in a width direction of the glass film. The protective sheet can further be wound on an outer peripheral surface of the glass film by winding only the protective sheet from a trailing end of the glass film in a winding direction of the glass film.

Abstract: A manufacturing method for a glass roll includes forming a glass film by a downdraw method, winding the glass film into a roll using a winding roller in a state in which front and back glass surfaces of the glass film formed in said forming operation are exposed, and during said winding operation, superposing the glass film on a separable protective sheet. The protective sheet extends beyond both sides in a width direction of the glass film. The method may further include winding the protective sheet on an outer peripheral surface of the glass film by winding only the protective sheet from a trailing end of the glass film in a winding direction of the glass film.

Abstract: Provided is a glass roll utilizing a flanged roll core, and reliably inhibiting a glass film from breaking from an end portion in a width direction thereof as an origin of breakage. A glass roll (1) is formed by winding a glass film (4) and a cushion sheet (5), under a state of being superposed, around a roll core (3) including a flange (2) at each end portion thereof, in which an end portion in a width direction of the glass film (4) is separated from the flange (2) on each side in the width direction of the glass film (4), and the cushion sheet (5) is extended beyond the end portion in the width direction of the glass film (4) to the flange (2) side, to thereby form an extension portion (5a).

Abstract: Provided is a glass roll formed by winding a glass film into a roll, in which a minimum winding radius of the glass film is optimized. Thus, the glass film is reliably prevented from breaking due to static fatigue, and is able to be stored for long periods. A glass roll (1), which is formed by winding a glass film (2) into a roll, has a configuration in which the glass film has a minimum winding radius (R) satisfying the following relation: R?(T/2)[(2.3/?)×E?1], where ? represents flexural strength of the glass film (2) obtained by a 3-point bending test, T represents a thickness of the glass film, and E represents a Young's modulus of the glass film.

Abstract: Provided is a glass roll (1), which is formed by winding a long glass film (2) into a roll, in which the long glass film (2) includes both end edges (2a) in a width direction larger in thickness relative to a center portion (2b) in the width direction, and the long glass film (2) is wound into a roll so that the both end edges (2a) overlap one another while interposing a protective sheet (10) therebetween. Specifically, the long glass film (2) is formed by a downdraw method with selvage portions (2a) left in the both end edges in the width direction, and the long glass film (2) is wound into a roll so that the selvage portions (2a) overlap one another.

Abstract: Provided is a glass roll formed by winding a glass film into a roll, in which a minimum winding radius of the glass film is optimized. Thus, the glass film is reliably prevented from breaking due to static fatigue, and is able to be stored for long periods. A glass roll (1), which is formed by winding a glass film (2) into a roll, has a configuration in which the glass film has a minimum winding radius (R) satisfying the following relation: R?(T/2)[(2.3/?)×E?1], where ? represents flexural strength of the glass film (2) obtained by a 3-point bending test, T represents a thickness of the glass film, and E represents a Young's modulus of the glass film.

Abstract: Provided is a glass roll utilizing a flanged roll core, and reliably inhibiting a glass film from breaking from an end portion in a width direction thereof as an origin of breakage. A glass roll (1) is formed by winding a glass film (4) and a cushion sheet (5), under a state of being superposed, around a roll core (3) including a flange (2) at each end portion thereof, in which an end portion in a width direction of the glass film (4) is separated from the flange (2) on each side in the width direction of the glass film (4), and the cushion sheet (5) is extended beyond the end portion in the width direction of the glass film (4) to the flange (2) side, to thereby form an extension portion (5a).

Abstract: Provided is a package form, with which cleanness of a glass film is ensured and the glass film is prevented from breaking. The package form is effective in minimizing the number of glass film processing steps to be performed before packaging and after unpackaging. As the package form for a glass film, provided is a glass roll (1) formed by winding a glass film (2) into a roll while superposing the glass film (2) on a protective sheet (3), the glass film (2) being formed by an overflow downdraw method and having exposed front and back surfaces.

Abstract: To provide a glass roll capable of reliably preventing a glass film from breaking from an end surface of the glass film as an origin of breakage, a glass roll (1) is formed by winding a glass film (2) into a roll while superposing the glass film (2) on a protective sheet (3), the glass film (2) being formed by an overflow downdraw method to have a thickness of 1 ?m or more and 200 ?m or less, and to have each end surface in a width direction to form a cut surface cut by laser splitting.