JP2011042508A - Glass roll - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the display characteristics, productivity and the like of a flexible device by originating a glass roll in which electrification by peeling is hardly caused when a glass film is pulled out sequentially although the surface quality of the glass film is superior. <P>SOLUTION: The glass roll prepared by winding the glass film having a film thickness of 200 μm or less into a roll form is characterized by having a dielectric constant of the glass film of 7 or less and an average surface roughness Ra of 10 Å or less. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a glass roll suitable for manufacturing a flexible device (hereinafter referred to as a flexible device), specifically, a substrate for a display such as a liquid crystal display or an organic EL display, and a chip size package. (CSP), charge coupled device (CCD), substrate for image sensor such as close proximity type solid-state imaging device (CIS), substrate for lighting device such as organic EL lighting, substrate for solar cell, cover glass for solar cell and wiring The present invention relates to a glass roll suitable for producing a substrate.

  In recent years, devices such as organic EL displays have been reduced in size, thickness, and weight. Moreover, these devices are mounted on mobile phones, notebook PCs, TVs, and the like, and it is desired to further reduce power consumption in the future. Moreover, these devices are not only used in a flat state but also used in a curved shape, for example, a display part of a flexible wristwatch, a display part installed on a curved wall or part of a pillar. The number of cases used for display units installed on the surface of automobile bodies is also increasing.

  At present, a glass substrate having a thickness of 0.5 to 0.7 mm is used for an organic EL display or the like, and since this glass substrate is poor in flexibility, it cannot be applied to a flexible device. However, if the plate thickness of the glass substrate is reduced, specifically, if the plate thickness of the glass substrate is 200 μm or less, the flexibility of the glass substrate is increased and the glass substrate can be applied to a flexible device.

  In addition, when a thin glass film (or a composite film of a glass film and a plastic film) is wound into a roll and made into a glass roll, a roll-to-roll process can be adopted when manufacturing a flexible device. As a result, the continuous production of the flexible device becomes possible, and the productivity of the flexible device is dramatically increased. Moreover, if a glass film is wound up in roll shape and made into a glass roll, the packing efficiency and conveyance efficiency of a glass film will also improve.

JP 2008-305557 A JP 2009-70759 A

  In an organic EL display or the like, a transparent electrode such as ITO is formed on a substrate. However, when the average surface roughness Ra of the glass film is large, specifically, when the average surface roughness Ra of the glass film is larger than 10 mm, the surface quality of the electrode film formed on the glass film is lowered, and as a result The unevenness of the electrode film may cause unevenness in the electric field distribution and cause display defects.

  On the other hand, when the average surface roughness Ra of the glass film is small, specifically, when the average surface roughness Ra of the glass film is 10 mm or less, when the glass film is successively drawn from the glass roll, the glass film-glass is continuously extracted. Since a peeled portion occurs between the films (or glass film-plastic film), charging occurs due to peeling at that portion, and foreign matter in the atmosphere is adsorbed to the glass film, and the glass film breaks down in subsequent steps. Inconveniences such as causing In the case of an organic EL display manufacturing process, when a glass film is placed on a metal stage and deposited on the surface of the glass film and then transported to the next process, the glass film is lifted with a lift pin. Problems such as the glass film being charged and the glass film being charged and broken are likely to occur.

  Thus, the charge breakdown is related to the average surface roughness Ra of the glass film. When the average surface roughness Ra of the glass film is larger than 10 mm as measured by AFM, the charge breakdown is less likely to occur. For this reason, if the surface of the glass film is roughened by etching or the like, charging breakdown is less likely to occur, but display defects due to the uneven shape of the electrode film are likely to occur, and the manufacturing cost of the glass film increases. Resulting in.

  Therefore, the present invention creates a glass roll that is less likely to be charged by peeling when the glass film is sequentially pulled out even though the surface quality of the glass film is good. Increasing productivity is a technical issue.

  As a result of repeating various experiments, the present inventor reduced the dielectric constant while increasing the surface quality of the glass film, and further wound the glass film into a roll to obtain the above technical problem. It is found that the problem can be solved, and is proposed as the present invention. That is, the glass roll of the present invention is a glass roll obtained by winding a glass film having a film thickness of 200 μm or less into a roll shape, wherein the glass film has a dielectric constant of 7 or less and an average surface roughness Ra of 10 μm or less. It is characterized by being. Here, the “glass roll” includes not only a roll of a glass film alone but also a roll of a composite film of a glass film and a plastic film. The “dielectric constant” refers to a value measured based on the method described in ASTM D150 at a frequency of 1 MHz and 25 ° C. Furthermore, “average surface roughness Ra” refers to a value measured based on the method described in JIS B0601: 2001, and can be measured by, for example, AFM. In addition, in the glass roll of this invention, average surface roughness Ra of a glass film should just have at least one surface (except an end surface) in the said range, and both surfaces (except an end surface) are in the said range. preferable.

  In the glass roll of the present invention, if the glass film has a dielectric constant of 7 or less, even when the surface quality of the glass film is high when the glass film is sequentially pulled out from the glass roll, the glass film is peeled off between the glass film. Since charging due to peeling is less likely to occur, foreign matter in the atmosphere is less likely to be adsorbed to the glass film, and the glass film is less likely to cause charge breakdown in subsequent steps. Moreover, in the glass roll of this invention, if the dielectric constant of a glass film shall be 7 or less, even if the surface quality of a glass film is high, a glass film will become difficult to carry out electrostatic breakdown in the manufacturing process of an organic EL display.

  In the glass roll of the present invention, if the average surface roughness Ra of the glass film is 10 mm or less, the surface quality of the transparent electrode such as ITO is improved on the glass film, so that the electric field distribution is uneven in the organic EL display or the like. This makes it difficult to cause display defects.

  2ndly, the glass roll of this invention is characterized by the film thickness of a glass film being 100 micrometers or less.

  Third, the glass roll of the present invention is characterized in that the dielectric loss tangent of the glass film is 0.5 or less. Here, “dielectric loss tangent” refers to a value measured based on the method described in ASTM D150 at a frequency of 1 MHz and 25 ° C.

Fourth, the glass roll of the present invention, glass films, as a glass composition, in _{mass%, SiO 2 40~80%, Al} 2 O 3 0~20%, B 2 O 3 0~30%, MgO 0 _{~15%, CaO 0~15%, SrO} 0~15%, BaO 0~15%, Li 2 O + Na 2 O + K 2 O (Li 2 O, Na 2 O, the total content of _{K 2} O) less than 0-10% It is characterized by containing.

Fifth, glass roll of the present invention, glass films, as a glass composition, in _{mass%, SiO 2 55~78%, Al} 2 O 3 10~20%, B 2 O 3 10~30%, MgO 0 ~4%, CaO 1~10%, SrO 0~5%, BaO 0~5%, wherein _{the Li 2 O + Na 2 O +} K 2 O containing 6%.

Sixth, in the glass roll of the present invention, the glass film has a glass composition of mass%, SiO ₂ 55 to 70%, Al ₂ O ₃ 10 to 20%, B ₂ O ₃ 13 to 20%, MgO 0. ~2%, CaO 6~10%, SrO 0~3%, BaO 0~3%, MgO + CaO + SrO + BaO (MgO, CaO, SrO, the total amount of _{BaO) 6.5~10%, Li 2 O} + Na 2 O + K 2 O 0 It is characterized by containing ~ 0.1%.

Seventh, the glass roll of the present invention is characterized in that the liquidus viscosity of the glass film is 10 ^4.0 dPa · s or more. Here, “liquid phase viscosity” refers to a value obtained by measuring the viscosity of glass at the liquid phase temperature by a platinum ball pulling method. In addition, the “liquid phase temperature” passes through a standard sieve 30 mesh (500 μm), and the glass powder remaining in 50 mesh (300 μm) is put in a platinum boat and kept in a temperature gradient furnace for 24 hours to precipitate crystals. Refers to the value measured for temperature. In addition, the higher the liquidus viscosity and the lower the liquidus temperature, the better the devitrification resistance and the moldability.

  Eighth, the glass roll of the present invention is characterized in that a glass film is formed by an overflow downdraw method. Here, the “overflow down draw method” is also referred to as a fusion method, in which molten glass overflows from both sides of a heat-resistant cage-like structure, and the overflowing molten glass joins at the lower end of the cage-like structure. However, this is a method for producing a glass film by stretching downward.

  Ninthly, the glass roll of the present invention is characterized by being wound in a state where the minimum curvature radius is 500 mm or less. When the glass film is wound in a state where the minimum curvature radius is 500 mm or less, the packing efficiency and the conveyance efficiency of the glass film are improved. The “minimum radius of curvature” usually corresponds to the radius of curvature of the innermost portion of the wound glass film.

  In the glass roll of the present invention, the glass film has a film thickness of 200 μm or less, preferably 100 μm or less, 80 μm or less, 50 μm or less, and particularly preferably 30 μm or less. The smaller the film thickness, the more flexible the glass film, so the minimum radius of curvature of the glass roll can be reduced. As a result, the packaging efficiency and transport efficiency of the glass film can be easily improved, and the device can be used. Flexibility is also easily improved. In addition, the smaller the film thickness, the lighter the glass roll and, as a result, the lighter the device.

  In the glass roll of the present invention, the dielectric constant of the glass film is 7 or less, preferably 6.5 or less, 6 or less, 5.3 or less, 5 or less, 4.9 or less, and particularly preferably 4.8 or less. When the dielectric constant is increased, the glass film is easily charged, and charging breakdown is easily caused. In addition, when the dielectric constant increases, in an organic EL device or the like, when a voltage is applied to the pixel electrode, the induced charge increases and the power consumption tends to increase. Further, the value of dielectric constant × film thickness is preferably 1400 μm or less, 1200 μm or less, 1000 μm or less, 800 μm or less, 500 μm or less, 300 μm or less, or 200 μm or less. As the value of dielectric constant × film thickness decreases, the flexibility of the glass film increases and it becomes easier to produce a glass roll that is less likely to be charged, and it is easier to reduce the weight of the glass roll.

  In the glass roll of the present invention, the average surface roughness Ra of the glass film is 10 mm or less, preferably 8 mm or less, 5 mm or less, 4 mm or less, 3 mm or less, particularly 2 mm or less. When the average surface roughness Ra is increased, display unevenness is likely to occur due to the unevenness of the film formed on the glass film in a device such as an organic EL.

  In the glass roll of the present invention, the dielectric loss tangent of the glass film is preferably 0.5 or less, 0.1 or less, 0.01 or less, 0.005 or less, 0.001 or less, and particularly preferably 0.0005 or less. When the dielectric loss tangent becomes high, the glass film tends to generate heat during device operation, which may adversely affect the operation characteristics of the device.

In the glass roll of the present invention, the density of the glass film is 2.6 g / cm ³ or less, 2.5 g / cm ³ or less, 2.45 g / cm ³ or less, 2.42 g / cm ³ or less, 2.40 g / cm ³ Hereinafter, it is preferably 2.38 g / cm ³ or less, 2.35 g / cm ³ or less, and particularly preferably 2.34 g / cm ³ or less. When the density is larger than 2.6 g / cm ³ , it is difficult to reduce the weight of the glass. Here, “density” refers to a value measured by the well-known Archimedes method.

In the glass roll of the present invention, the thermal expansion coefficient of the glass film is 25-50 × 10 ⁻⁷ / ° C., 29-45 × 10 ⁻⁷ / ° C., 31-39 × 10 ⁻⁷ / ° C., 32-38 × 10 ^{− 7} / ° C., 33-37 × 10 ⁻⁷ / ° C., particularly 33-35 × 10 ⁻⁷ / ° C. is preferable. When the thermal expansion coefficient is outside the above range, the glass film tends to warp due to a difference in thermal expansion coefficient from a film such as a TFT. In addition, a glass film becomes easy to warp, so that film thickness is small. For this reason, the smaller the film thickness, the higher the necessity of regulating the thermal expansion coefficient within the above range.

  In the glass roll of the present invention, the strain point of the glass film is preferably 500 ° C. or higher, 550 ° C. or higher, 620 ° C. or higher, 630 ° C. or higher, 640 ° C. or higher, 650 ° C. or higher, particularly 660 ° C. or higher. When the strain point is low, the glass film is likely to be thermally contracted in the manufacturing process of the p-Si • TFT when used for an organic EL display substrate.

High temperature melting increases the burden on the glass melting furnace. Refractories such as alumina and zirconia used in a glass melting furnace are eroded violently by molten glass as the temperature rises. When the erosion amount of the refractory is increased, the life cycle of the glass melting furnace is shortened, and as a result, the manufacturing cost of the glass film is increased. Moreover, when performing high temperature melting, since it is necessary to use a highly heat-resistant structural member for the structural member of a glass melting kiln, the structural member of a glass melting kiln becomes expensive, As a result, a melting cost rises. Furthermore, high-temperature melting requires that the inside of the glass melting furnace be kept at a high temperature, so that the running cost is higher than that at low-temperature melting. Therefore, in the glass roll of the present invention, the temperature at 10 ^2.5 dPa · s of the glass film is preferably 1590 ° C. or lower, 1580 ° C. or lower, 1570 ° C. or lower, 1560 ° C. or lower, particularly 1550 ° C. or lower. When the temperature at 10 ^2.5 dPa · s is higher than 1590 ° C., low-temperature melting becomes difficult and the bubble quality tends to be lowered, and as a result, the production cost of the glass film is likely to increase. Here, “temperature at 10 ^2.5 dPa · s” corresponds to the melting temperature and indicates a value measured by a platinum ball pulling method.

  In the glass roll of the present invention, the liquidus temperature of the glass film is preferably 1180 ° C. or lower, 1150 ° C. or lower, 1110 ° C. or lower, 1070 ° C. or lower. If it does in this way, since it becomes difficult to generate | occur | produce a devitrification crystal | crystallization in glass, it will become easy to shape | mold a glass film by the overflow downdraw method etc. For this reason, the manufacturing cost of a glass film can be reduced, improving the surface quality of a glass film. The liquidus temperature is an index of devitrification resistance. The lower the liquidus temperature, the better the devitrification resistance.

In the glass roll of the present invention, the liquidus viscosity of the glass film is 10 ^4.5 dPa · s or more, 10 ^5.0 dPa · s or more, 10 ^5.5 dPa · s or more, 10 ^5.7 dPa · s or more, In particular, 10 ^5.8 dPa · s or more is preferable. In this way, devitrification crystals are less likely to occur during molding, making it easier to mold glass films using the overflow downdraw method, etc., and improving the surface quality of glass films while reducing glass film manufacturing costs. can do. The liquid phase viscosity is an index of moldability. The higher the liquid phase viscosity, the better the moldability.

  The glass roll of the present invention is preferably wound with a minimum curvature radius of 500 mm or less (desirably 300 mm or less, 150 mm or less, 100 mm or less, 70 mm or less, 50 mm or less, particularly 30 mm or less). If it winds in the state where the minimum curvature radius is small, the packing efficiency and conveyance efficiency of a glass film will improve.

  The glass roll of the present invention is preferably wound around a core. In this way, when winding the glass film, the glass film can be fixed to the core, so even if an external pressure is applied to the glass roll, the deformation of the glass film is suppressed by the core and the glass film is damaged. Can be prevented. Moreover, in order to prevent the winding core from being damaged from the end face of the glass film due to external factors, the winding core is preferably longer than the width of the glass film. In addition, the material of a core is not specifically limited, A thermoplastic resin, a paper tube, etc. can be used.

  In the glass roll of the present invention, a buffer film made of resin or paper (interleaf) may be inserted between the glass film and the glass film in order to increase the impact resistance, and in order to increase the mechanical strength, The end face may be coated with resin.

  When the glass roll of the present invention is wound after scribing the end (ear part) in the width direction of the glass film, the glass roll is preferably wound so that the scribe line is on the inner side. If it does in this way, it will become difficult to generate | occur | produce a crack from the end surface of a glass film. On the other hand, when the scribe line is wound outward, the glass film tends to be damaged due to the fine scratches generated in the groove of the scribe line due to tensile stress. Such fine scratches can be reduced by chemical polishing or fire polishing.

  In the glass roll of the present invention, the end of the glass film is preferably cut and separated with a laser. If it does in this way, since the edge part of a glass film can be continuously cut-separated after shaping | molding of a glass film, while improving the production efficiency of a glass roll, it becomes difficult to generate | occur | produce a crack from the end surface of a glass film. . As the laser, a carbon dioxide laser, a YAG laser, or the like can be used. The output of the laser is preferably adjusted so that the progress rate of cracks progressed by the laser matches the drawing speed of the glass film. In this case, the ratio of speed ratio = (crack speed developed by laser−plate drawing speed) / (plate drawing speed) × 100 is ± 10% or less, ± 5% or less, ± 1% or less, ± 0.5 % Or less, preferably ± 0.1% or less.

  The reason why the glass composition of the glass film of the present invention is limited to the above range is shown below.

The content of SiO ₂ is 40 to 80%, preferably 50 to 78%, more preferably 50 to 70%, still more preferably 55 to 65%, particularly preferably 57 to 63%, and most preferably 58 to 62%. is there. When the content of SiO ₂ is less than 40%, it is difficult to reduce the density. On the other hand, when the content of SiO ₂ is more than 80%, the high temperature viscosity becomes high and the meltability is lowered. In addition, defects such as devitrified crystals (cristobalite) are likely to occur in the glass.

The content of Al ₂ O ₃ is 0 to 20%. When the content of Al ₂ O ₃ is less or hardly enhance the heat resistance, the higher the viscosity at high temperature, the melting property tends to decrease. Therefore, the preferred lower limit range of Al ₂ O ₃ is 0.1% or more, 3% or more, 5% or more, 10% or more, 12% or more, 14% or more, 14.5% or more, 15% or more, particularly 15 .5% or more. On the other hand, when the content of Al ₂ O ₃ is large, the liquidus temperature increases, devitrification resistance tends to decrease. Therefore, the preferable upper limit range of Al ₂ O ₃ is 19% or less, 18% or less, and particularly 17% or less.

B ₂ O ₃ is a component that lowers the dielectric constant. Moreover, it is a component which acts as a flux and lowers the high temperature viscosity to increase the meltability, and its content is 0 to 30%. When the content of B ₂ O ₃ is small, it becomes difficult to lower the dielectric constant, and the function as a flux becomes insufficient, so that the high-temperature viscosity becomes high and the bubble quality tends to be lowered. Furthermore, it is difficult to reduce the density of the glass. Therefore, the preferable lower limit range of B ₂ O ₃ is 0.1% or more, 3% or more, 5% or more, 11% or more, 11.5% or more, 12% or more, 13% or more, 14% or more, 15% Above, especially 15.5% or more. On the other hand, if the content of B ₂ O ₃ is large, heat resistance and weather resistance tends to lower. Therefore, the preferable upper limit range of B ₂ O ₃ is 25% or less, 20% or less, 19% or less, 18% or less, particularly 17% or less.

  MgO is a component that increases the meltability by lowering the high-temperature viscosity without lowering the strain point, and is the component that has the effect of reducing the density most among the alkaline earth metal oxides. 0-15%, 0-10%, 0-6%, 0-2%, 0-1%, 0-0.5%, 0-0.1% are preferable. However, when the content of MgO is too large, the dielectric constant and dielectric loss tangent tend to be high. Moreover, when there is too much content of MgO, liquidus temperature will rise, devitrification resistance will fall easily, and also it will become easy to phase-divide glass, and there exists a possibility that transparency may be impaired.

  The content of CaO is 0 to 15%. CaO is a component that lowers the high-temperature viscosity without significantly lowering the strain point and significantly increases the meltability, and is a component that has a large effect of suppressing devitrification in the glass composition system according to the present invention. Furthermore, when the content is relatively increased in the alkaline earth metal oxide, the glass is easily reduced in density. Therefore, the preferable lower limit range of CaO is 0.1% or more, 1% or more, 2% or more, 3% or more, 6% or more, 6.5% or more, particularly 7% or more. On the other hand, if the content of CaO is large, the dielectric constant and dielectric loss tangent are likely to be high, the thermal expansion coefficient and density are too high, the component balance of the glass composition is impaired, and devitrification resistance is likely to be reduced. Become. Therefore, the preferable upper limit range of CaO is 12% or less, 9.5% or less, 9% or less, and particularly 8.5% or less.

  The content of SrO is 0 to 15%. SrO is a component that increases the meltability by lowering the high-temperature viscosity without lowering the strain point. However, as the SrO content increases, the density and thermal expansion coefficient tend to increase, and the dielectric constant and dielectric loss tangent. Will also rise. In addition, when the SrO content increases, the content of CaO or MgO must be relatively decreased in order to match the thermal expansion coefficient of a film such as a TFT, and this is due to the decrease in the content. , Devitrification resistance is reduced, and high temperature viscosity is likely to increase. Therefore, the content of SrO is 0-10%, 0-8%, 0-5%, 0-2%, 0-1.5%, 0-1%, 0-0.5%, especially 0-0. .1% is preferred.

  The content of BaO is 0 to 10%. BaO is a component that increases the meltability by lowering the high-temperature viscosity without lowering the strain point. However, as the content of BaO increases, the density and thermal expansion coefficient tend to increase, and the dielectric constant and dielectric loss tangent. Will also rise. In addition, when the content of BaO increases, the content of CaO or MgO must be relatively reduced in order to match the thermal expansion coefficient of a film such as a TFT. As a result, the devitrification resistance is reduced. It becomes easy to invite the situation which falls or high temperature viscosity rises. Therefore, the content of BaO is 0-10%, 0-8%, 0-5%, 0-2%, 0-1.5%, 0-1%, 0-0.5%, especially 0-0. Less than 1% is preferable.

  MgO + CaO + SrO + BaO is a component that lowers the liquidus temperature and makes it difficult to generate crystalline foreign matter in the glass, and is a component that improves meltability and formability, and its content is 0 to 25%, 1 to 20%, 3 to 15%, 5 to 10%, 6.5 to 9.5%, particularly 7 to 9% are preferable. If the content of MgO + CaO + SrO + BaO is low, the function as a flux cannot be fully exhibited, and in addition to the decrease in meltability, the thermal expansion coefficient becomes too low and it is difficult to match the thermal expansion coefficient of a film such as a TFT. Become. On the other hand, if the content of MgO + CaO + SrO + BaO is large, the density increases, it becomes difficult to reduce the weight of the glass, the specific Young's modulus decreases, and the thermal expansion coefficient becomes too high.

When the content of Li ₂ O + Na ₂ O + K ₂ O increases, the thermal expansion coefficient increases, the strain point decreases, and the TFT characteristics deteriorate. Therefore, the content of Li ₂ O + Na ₂ O + K ₂ O is preferably 0 to less than 10%, 0 to 6%, 0 to less than 5%, 0 to 3%, 0 to 1%, particularly preferably 0 to 0.1%. Ideally, it is desirable not to contain substantially. Here, "substantially free of _{Li 2 O + Na 2 O +} K 2 O ", the content of _{Li 2 O + Na 2 O +} K 2 O in the glass composition refers to a case of less than 0.1%.

  Besides the above components, other components can be added to the glass composition, for example, up to 25%, preferably up to 15%.

A fining agent is a component used to improve foam quality. Conventionally, As ₂ O ₃ and Sb ₂ O ₃ have been used as fining agents. However, As ₂ O ₃ and Sb ₂ O ₃ are environmentally hazardous substances, and it is required to reduce their usage from an environmental point of view. Therefore, when SnO ₂ is used as a fining agent, the foam quality can be improved while considering environmental requirements.

SnO ₂ is a component that exhibits a good clarification action in a high temperature range and a component that lowers the high temperature viscosity, and its content is 0 to 1%, 0.001 to 1%, 0.01 to 0.00. 5%, particularly 0.05 to 0.3% is preferable. When the content of SnO ₂ is more than 1%, a devitrified crystal of SnO ₂ is likely to be precipitated in the glass. Incidentally, when the content of SnO ₂ is less than 0.001%, it becomes difficult to enjoy the effect of the above.

As ₂ O ₃ and Sb ₂ O ₃ also act effectively as fining agents, and the glass film according to the present invention does not completely exclude the inclusion of these components, but from an environmental point of view, It is preferable to regulate the content to less than 0.1%, particularly less than 0.05%. In addition, halogens such as F and Cl lower the melting temperature and promote the action of the clarifying agent. As a result, it is possible to extend the life of the glass manufacturing kiln while reducing the melting cost. it can. However, if the content of F or Cl is too large, the metal wiring pattern formed on the glass film may be corroded. Therefore, the contents of F and Cl are preferably 1% or less, 0.5% or less, less than 0.1%, 0.05% or less, particularly 0.01% or less, respectively.

As described above, SnO ₂ is suitable as a fining agent, but CeO ₂ , SO ₃ , C, and metal powder (eg, Al, Si, etc.) can be added up to 5% as long as the glass properties are not impaired.

  ZnO is a component that enhances meltability, but as its content increases, the dielectric constant and dielectric loss tangent increase, the glass tends to devitrify, the strain point decreases, and the density also increases easily. Become. Therefore, the content of ZnO is preferably 0 to 10%, 0 to 5%, 0 to 3%, 0 to 0.5%, particularly preferably 0 to 0.3%, and ideally not substantially contained. desirable. Here, “substantially does not contain ZnO” refers to a case where the content of ZnO in the glass composition is 0.1% or less.

ZrO ₂ is a component that enhances the weather resistance, but as its content increases, the dielectric constant and dielectric loss tangent increase. Therefore, the content of ZrO ₂ is preferably 0 to 5%, 0 to 3%, 0 to 0.5%, particularly preferably 0 to 0.2%, and ideally not substantially contained. Here, “substantially does not contain ZrO ₂ ” refers to a case where the content of ZrO _{2 in} the glass composition is 0.01% or less. Incidentally, For greater weather resistance, it is preferable that a content of ZrO ₂ in 0.01% or more.

TiO ₂ is a component that lowers the viscosity at high temperature and increases the meltability, and is a component that suppresses solarization, but when added in a large amount in the glass composition, the dielectric constant and dielectric loss tangent increase, and the glass is colored. , The transmittance tends to decrease. Therefore, the content of TiO ₂ is preferably 0 to 5%, 0 to 3%, 0 to 1%, particularly preferably 0 to 0.02%.

P ₂ O ₅ is a component that enhances devitrification resistance. However, when it is added in a large amount in the glass composition, in addition to the occurrence of phase separation and milk white in the glass, the water resistance is significantly reduced. Therefore, the content of P ₂ O ₅ is preferably 0 to 5%, 0 to 1%, particularly preferably 0 to 0.5%.

Y ₂ O ₃ , Nb ₂ O ₅ , and La ₂ O ₃ have a function of increasing the strain point. However, when the content thereof is large, the dielectric constant, dielectric loss tangent, and density are likely to increase. Therefore, the content of these components is preferably 0 to 3%, 0 to 1%, particularly preferably 0 to 0.1%, respectively.

If the glass composition according to the present invention defines the glass composition range as follows, the dielectric constant is lowered, and it is easy to match the thermal expansion coefficient of a film such as a TFT, and the high temperature viscosity is lowered. Phase viscosity tends to increase. (1) as a glass composition, in _{mass%, SiO 2 50~70%, Al} 2 O 3 0.1~20%, B 2 O 3 11~25%, MgO + CaO + SrO + BaO 5~13%, 0~10% MgO, CaO 0-9%, SrO 0-7%, BaO 0-7%, As ₂ O ₃ content less than 0.5%, Sb ₂ O ₃ content less than 0.5%, F The content is less than 0.1%, the Cl content is less than 0.1%, the alkali metal oxide content is less than 10%,
(2) as a glass composition, in _{mass%, SiO 2 55~70%, Al} 2 O 3 11~18%, B 2 O 3 12~22%, MgO + CaO + SrO + BaO 7~11%, MgO 0~9%, CaO 0 0.1 to 9%, SrO 0 to 6%, BaO 0 to 6%, As ₂ O ₃ content less than 0.1%, Sb ₂ O ₃ content less than 0.1%, F The content is less than 0.1%, the Cl content is less than 0.1%, the alkali metal oxide content is less than 5%,
(3) as a glass composition, in _{mass%, SiO 2 55~70%, Al} 2 O 3 12~17%, B 2 O 3 12~19%, MgO + CaO + SrO + BaO 7~11%, 0~5% MgO, CaO 2 -9%, SrO 0-3%, BaO 0-3%, As ₂ O ₃ content less than 0.1%, Sb ₂ O ₃ content less than 0.1%, F content Is less than 0.1%, the Cl content is less than 0.1%, the alkali metal oxide content is less than 1%,
(4) as a glass composition, in _{mass%, SiO 2 55~65%, Al} 2 O 3 13~18%, B 2 O 3 13~19%, MgO + CaO + SrO + BaO 7~10%, 0~1% MgO, CaO 6 0.5-9%, SrO 0-1%, BaO 0-1%, As ₂ O ₃ content less than 0.05%, Sb ₂ O ₃ content less than 0.05%, The content is less than 0.1%, the Cl content is less than 0.1%, the alkali metal oxide content is less than 0.1%,
(5) as a glass composition, in _{mass%, SiO 2 57~63%, Al} 2 O 3 15~17%, B 2 O 3 15~18%, MgO + CaO + SrO + BaO 7~9%, 0~1% MgO, CaO 7 -9%, SrO 0-0.5%, BaO 0-0.5%, SnO ₂ 0.01-0.6%, As ₂ O ₃ content less than 0.05%, Sb ₂ O ₃ content is less than 0.05%, F content is less than 0.1%, Cl content is less than 0.1%, and alkali metal oxide content is less than 0.1%.

In order to lower the dielectric constant of the glass film, it is generally effective to increase the content of SiO ₂ in the glass composition. However, in the case of an alkali-free glass or a low alkali glass, increasing the SiO ₂ content may significantly decrease the meltability. However, if the glass composition range is regulated as in the above (3) to (5), it is possible to suppress a decrease in meltability while reducing the dielectric constant.

  In the glass roll of the present invention, a glass batch prepared so as to have a predetermined glass composition is put into a continuous glass melting furnace, and after the glass batch is heated and melted, the obtained molten glass is clarified and put into a molding apparatus. After being supplied, it can be formed into a thin plate shape or the like and wound into a roll.

  In the glass roll of the present invention, the glass film is preferably formed by an overflow down draw method. In this way, a glass film that is unpolished and has good surface quality can be produced. The reason is that, in the case of the overflow downdraw method, the surface to be the surface of the glass film does not come into contact with the bowl-like refractory and is molded in a free surface state. The structure and material of the bowl-shaped structure are not particularly limited as long as desired dimensions and surface quality can be realized. Moreover, in order to perform the downward extending | stretching shaping | molding, the method of applying force with respect to a glass film will not be specifically limited if a desired dimension and surface quality are realizable. For example, a method may be adopted in which a heat-resistant roll having a sufficiently large width is rotated and stretched in contact with the glass film, or a plurality of pairs of heat-resistant rolls are only near the end face of the glass film. You may employ | adopt the method of making it contact and extending | stretching. The lower the liquidus temperature and the higher the liquidus viscosity, the easier it is to mold the glass film by the overflow downdraw method.

  Various molding methods can be applied in addition to the overflow downdraw method. For example, a slot down draw method, a redraw method, or the like can be applied.

  Hereinafter, based on an Example, this invention is demonstrated in detail.

  Table 1 shows glass samples (sample Nos. 1 to 10) according to the present invention.

Sample no. 1-10 were produced. First, a glass batch prepared so as to have the glass composition shown in the table was put in a platinum crucible, melted at 1600 ° C. for 24 hours, and then poured out onto a carbon plate to form a flat plate shape. Next, for each sample obtained, dielectric constant, dielectric loss tangent, the density, the thermal expansion coefficient alpha, strain point, annealing point, softening ^point, temperature at ^{10 4.0 dPa · s, 10 3.0} dPa · s at a ^temperature, temperature at ¹⁰ 2.5 dPa · s, the liquid phase temperature TL, to evaluate the liquidus viscosity LogitaTL.

  The dielectric constant and dielectric loss tangent are values measured based on the method described in ASTM D150 at a frequency of 1 MHz and 25 ° C.

  The density is a value measured by a well-known Archimedes method.

  The thermal expansion coefficient α is a value measured with a dilatometer, and is an average value in a temperature range of 30 to 380 ° C.

  The strain point, annealing point, and softening point are values measured based on the method described in ASTM C336.

The temperature at 10 ^4.0 dPa · s, the temperature at 10 ^3.0 dPa · s, and the temperature at 10 ^2.5 dPa · s are values measured by the platinum ball pulling method.

  The liquid phase temperature TL passes through a standard sieve 30 mesh (500 μm), and the glass powder remaining in 50 mesh (300 μm) is placed in a platinum boat and held in a temperature gradient furnace for 24 hours to measure the temperature at which crystals precipitate. It is the value.

  The liquid phase viscosity log ηTL is a value obtained by measuring the viscosity of the glass at the liquid phase temperature TL by the platinum pulling method.

As is clear from Table 1, sample No. In Nos. 1 to 10, since the glass composition is regulated within a predetermined range, the dielectric constant is 4.93 or less, the dielectric loss tangent is 0.0007 or less, the density is 2.39 g / cm ³ or less, and the thermal expansion coefficient α is 30 to 30. 35 × 10 ⁻⁷ / ° C., strain point was 511 ° C. or higher, temperature at 10 ^2.5 dPa · s was 1548 ° C. or lower, liquidus temperature TL was 1190 ° C. or lower, and liquidus viscosity logηTL was 4.0 or higher. . Sample No. 1-10, but it does not contain _{As 2 O 3, Sb 2 O} 3 in the glass composition, the foam quality was good.

  In the test melting furnace, sample No. 1 to 10 were melted, and a glass film having a film thickness of 50 μm and an average surface roughness Ra of 2 mm was formed by an overflow downdraw method or a redraw method, and then wound into a roll to obtain a glass roll. During molding, the surface of the glass film is appropriately adjusted by adjusting the speed of the pulling roller, the speed of the cooling roller, the temperature distribution of the heating device, the temperature of the molten glass, the flow rate of the molten glass, the drawing speed, the rotational speed of the stirring stirrer, etc. The quality was adjusted. The average surface roughness Ra is a value measured based on the method described in JIS B0601: 2001.

  Furthermore, the glass film (sample No. 1) obtained in [Example 2] was cut into a 300 mm square, and both surfaces of the glass film were washed with ethanol and then neutralized with an ionizer. Next, the glass film was placed on an aluminum substrate incorporating lift pins for lifting the glass film at four corners and vacuum-adsorbed with air for 30 seconds, and then the glass film and the aluminum substrate were peeled off. In the central portion of the glass film on the side not in contact with the aluminum substrate, the maximum charge amount immediately after peeling and the charge amount after 3 minutes were measured with a surface potentiometer. The amount of charge after the lapse of minutes was −80V.

On the other hand, a glass film (film thickness: 50 μm, dielectric constant: 7.6, average surface roughness Ra: 2 mm, glass composition: SiO ₂ 55.8%, Al ₂ O ₃ obtained by the method of [Example 2] 7.0%, MgO 1.9%, CaO 2.0%, SrO 8.9%, BaO 8.5%, ZrO ₂ 4.6%, Na ₂ O 4.3%, K ₂ O 7.0 %), The maximum charge amount immediately after peeling was −350 V, and the charge amount after 3 minutes was −150 V. The temperature at the time of measurement was 23 ° C. and the humidity was 40%.

Claims (9)

A glass roll obtained by winding a glass film having a film thickness of 200 μm or less into a roll,
A glass roll, wherein the glass film has a dielectric constant of 7 or less and an average surface roughness Ra of 10 mm or less.   The glass roll according to claim 1, wherein the glass film has a film thickness of 100 μm or less.   The glass roll according to claim 1 or 2, wherein the dielectric loss tangent of the glass film is 0.5 or less. Glass film, as a glass composition, in _{mass%, SiO 2 40~80%, Al} 2 O 3 0~20%, B 2 O 3 0~30%, 0~15% MgO, CaO 0~15%, SrO _0~15%, BaO _0~15%, glass roll according to claim 1, characterized by containing less than _{Li 2 O + Na 2 O +} K 2 O 0~10%. Glass film, as a glass composition, in _{mass%, SiO 2 55~78%, Al} 2 O 3 10~20%, B 2 O 3 10~30%, 0~4% MgO, CaO 1~10%, SrO _0~5%, BaO _0~5%, a glass roll according to any one of claims 1 to 4, characterized in _{that Li 2 O + Na 2 O +} K 2 O containing 6%. Glass film, as a glass composition, in _{mass%, SiO 2 55~70%, Al} 2 O 3 10~20%, B 2 O 3 13~20%, 0~2% MgO, CaO 6~10%, SrO 0~3%, BaO 0~3%, MgO + CaO + SrO + BaO 6.5~10%, according to any one of claims 1 to 5, characterized in that _{Li 2 O + Na 2 O +} K 2 O containing 0 to 0.1% Glass roll. The glass roll according to claim 1, wherein the glass film has a liquidus viscosity of 10 ^4.0 dPa · s or more.   The glass roll according to any one of claims 1 to 7, wherein the glass film is formed by an overflow downdraw method.   The glass roll according to any one of claims 1 to 8, wherein the glass roll is wound with a minimum curvature radius of 500 mm or less.