JP2018177602A - Glass plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass plate which is excellent in bending workability and can effectively attenuate collision energy of a scattering piece even when a thickness and a degree of crystallization are small.SOLUTION: A glass plate is a glass plate to be combined and integrated with a resin plate to prepare a glass resin composite body, and contains, by mol%, 45-80% of SiO, 5-30% of AlO, 0-20% of LiO+NaO+KO, 3-35% of MgO, 0-15% of CaO+SrO+BaO, as a glass composition.SELECTED DRAWING: Figure 1

Description

  TECHNICAL FIELD The present invention relates to a glass plate for producing a glass resin composite by combining and integrating with a resin plate, and more particularly to a glass plate used for a glass resin composite suitable for windshields and door glasses of automobiles.

  As window glass for vehicles etc., generally, laminated glass in which a plurality of soda lime glass plates are combined and integrated by an organic resin middle layer is used, and for the purpose of weight reduction, a plurality of soda lime glass plates There is also a case where a glass resin composite in which an organic resin intermediate layer and a resin plate are combined and integrated is used (see Patent Documents 1 to 4).

  The soda lime glass plate used for window glass of vehicles etc. has a function of attenuating the collision energy of the scattering fragments by deforming the tip shape of the scattering fragments such as flying stones during running to increase the impact resistance thereof. Have.

  However, the soda lime glass plate can not be said to be sufficiently effective in increasing the impact resistance of the scattering pieces. At present, the impact resistance of the scattering pieces is increased by increasing the thickness of the soda lime glass plate or by increasing the number of laminated sheets, but with this, the thickness and weight of the window glass are increased.

Then, in order to raise the impact resistance of a scattering piece, using a crystallized glass board instead of a soda lime glass board is examined. For example, a crystal formed by depositing a Li ₂ O-Al ₂ O ₃ -SiO ₂ -based crystal such as β-quartz solid solution (Li ₂ O.Al ₂ O ₃ .nSiO ₂ [where n 2 2]) as a main crystal. Glass plates are being considered.

JP, 2012-144217, A Unexamined-Japanese-Patent No. 2004-196184 JP 2001-151539 A Japanese Utility Model Publication No. 1-8821

  By the way, when the crystallization degree of the crystallized glass is increased, the hardness of the crystallized glass is increased and the collision energy of the scattering pieces may be attenuated, but the precipitated crystal inhibits the softening deformation, which makes the bending process difficult. It becomes impossible to apply to the windshield etc. of a car. In addition, increasing the thickness of the crystallized glass may attenuate the collision energy of the scattering pieces, but in this case, the weight of the window glass may be increased, and the transparency may be impaired.

  Therefore, the present invention has been made in view of the above-mentioned circumstances, and the technical problem is that it is excellent in bending workability and can effectively attenuate the collision energy of the scattering fragments even if the thickness and the degree of crystallization are small. It is to devise a glass plate.

The present inventors have found that the above technical problems can be solved by strictly controlling the glass composition range of the glass sheet, and propose the present invention as the present invention. That is, the glass plate of the present invention is a glass plate for producing a glass resin composite by being compositely integrated with a resin plate, and the composition of the glass is, by mole%, SiO ₂ 45-80%, Al ₂ O _{3 5~30%, Li 2 O +} Na 2 O + K 2 O 0~20%, MgO 3~35%, characterized in that it contains 0~15% CaO + SrO + BaO. Here, “Li ₂ O + Na ₂ O + K ₂ O” refers to the total amount of Li ₂ O, Na ₂ O and K ₂ O. "CaO + SrO + BaO" refers to the total amount of CaO, SrO and BaO.

  The glass plate of the present invention is a glass plate for producing a glass resin composite by combining and integrating with a resin plate. In a glass resin composite, a glass plate is a material having transparency and enhancing impact resistance. The resin plate is a material that reduces the impact due to the collision of the scattering pieces and prevents the scattering of the glass pieces due to the impact of the scattering pieces. By providing both, impact resistance performance can be easily secured.

FIG. 1 is a schematic view for explaining an example of a glass resin composite. The glass resin composite 10 has a glass plate 11, a glass plate 12, and a resin plate 13 in this order from the outside, and these have a three-dimensionally curved curved shape and are not shown. Composite integrated by the organic resin interlayer. The glass plate 11 has, as a glass composition, SiO ₂ 45-80%, Al ₂ O ₃ 5-30%, Li ₂ O + Na ₂ O + K ₂ O 0-20%, MgO 3 35%, CaO + SrO + BaO 0 at a mole%. Similarly, the glass plate 12 contains 15%, and as a glass composition, SiO ₂ 45-80%, Al ₂ O ₃ 5-30%, Li ₂ O + Na ₂ O + K ₂ O 0 in mole%. It contains 20%, 3 to 35% of MgO, and 0 to 15% of CaO + SrO + BaO. The resin plate 13 is a polycarbonate.

  When the present inventors etc. analyzed the collision of the scattering piece in detail, it turned out that the scattering piece penetrates the inside of a glass plate first, after a glass plate is damaged by the shock wave by the collision of the scattering piece. And when the shock wave by the collision of a scattering piece is disperse | distributed, it turned out that the collision energy of a scattering piece can be attenuated and penetration of a scattering piece can be prevented. Further, when the shock wave is analyzed in detail, when the shock wave disperses and attenuates in the traveling direction of the scattering pieces and the perpendicular direction, the speed of the shock wave becomes faster in proportion to the Young's modulus of the glass plate. Then, since the glass plate of the present invention has the above-described glass composition, and in particular, contains 3 mol% or more of MgO in the glass composition, the Young's modulus can be increased. As a result, when the scattering pieces collide, the dispersion area of the shock wave becomes wider, the energy absorption of the shock wave becomes larger, and the speed of the scattering pieces themselves can be effectively reduced. As a result, the scattering pieces are less likely to penetrate the inside of the glass plate.

  Moreover, it is preferable that the glass plate of this invention is 80 GPa or more in Young's modulus. In this case, since the velocity of the shock wave in the glass plate is increased, the dispersion region of the shock wave is expanded, and the collision energy of the scatterer can be greatly attenuated. Here, "Young's modulus" refers to a value measured by a known resonance method.

  The glass plate of the present invention preferably has a crack resistance of 500 gf or more. In this way, since the glass plate is less likely to be scratched, it is possible to prevent the reduction in strength due to the scratch. Moreover, the fall of the transparency by a flaw can also be prevented. Here, “crack resistance” is a load at which the crack occurrence rate becomes 50%. The “crack occurrence rate” is a value measured as follows. First, in a constant temperature and humidity chamber maintained at a humidity of 30% and a temperature of 25 ° C., a Vickers indenter set to a predetermined load is driven on a glass surface (optically polished surface) for 15 seconds, and 15 seconds later, it is generated from four corners of the indentation. Count the number of cracks (up to 4 per indentation). Thus, after the indenter is driven 20 times and the total number of cracks is determined, it is determined by the equation (total number of cracks / 80) × 100.

  Moreover, it is preferable that the glass plate of this invention is 30% or less in crystallinity degree. In this way, it is possible to improve the bending processability of the glass sheet. Here, the “degree of crystallization” is obtained by measuring the area of the halo corresponding to the mass of the amorphous and the area of the peak corresponding to the mass of the crystal by measuring XRD by the powder method, The area of the peak] × 100 / [area of peak + area of halo] (%) is a value determined by the formula.

  The glass plate of the present invention preferably has a thickness of 3 to 15 mm.

  Moreover, it is preferable that the glass plate of this invention has a curved-surface shape curved three-dimensionally. In this way, it becomes easy to apply to the windshield etc. of a car.

It is the schematic for demonstrating an example of a glass resin composite.

The glass plate of the present invention has, in terms of mole%, glass composition, SiO ₂ 45-80%, Al ₂ O ₃ 5-30%, Li ₂ O + Na ₂ O + K ₂ O 0-20%, MgO 3 35%, CaO + SrO + BaO It contains 0 to 15%. The reason for restricting the content range of each component as described above is shown below. In addition, in description of the content range of each component,% indication shall refer to mol%.

SiO ₂ is a component that forms a glass network. The content of SiO ₂ is preferably 45 to 80%, 52 to 75%, in particular 58 to 72%. When the content of SiO ₂ is too small, it is difficult to vitrify and the weather resistance is easily lowered. On the other hand, when the content of SiO ₂ is too large, the meltability and the formability easily decrease, and the thermal expansion coefficient becomes too low, and it becomes difficult to match the thermal expansion coefficient of the resin plate or the organic resin intermediate layer.

Al ₂ O ₃ is a component that enhances Young's modulus and weather resistance. The content of Al ₂ O ₃ is preferably 5 to 30%, 9 to 25%, 15 to 24%, in particular 18 to 23%. When the content of Al ₂ O ₃ is too small, Young's modulus and weather resistance tend to be lowered. On the other hand, when the content of Al ₂ O ₃ is too large, the meltability, the formability and the devitrification resistance tend to be lowered.

Li ₂ O, Na ₂ O and K ₂ O are components that reduce the high temperature viscosity to improve the meltability, formability and bendability. The total amount of Li ₂ O, Na ₂ O and K ₂ O is preferably 0 to 20%, 1 to 15%, especially 5 to 12%. The content of each of Li ₂ O and K ₂ O is preferably 0 to 15%, 0 to 3%, in particular 0 to less than 1%. The content of Na ₂ O is preferably 0 to 15%, 1 to 12%, in particular 3 to 10%. When the content of Li ₂ O, Na ₂ O and K ₂ O is too large, the crack resistance and the weather resistance tend to be lowered.

  MgO is a component that greatly enhances the Young's modulus and crack resistance, and is also a component that reduces the high temperature viscosity and enhances the meltability, the formability, and the bendability. The content of MgO is preferably 3 to 35%, 8 to 33%, 12 to 32%, in particular 15 to 30%. When the content of MgO is too small, it becomes difficult to receive the above effect. On the other hand, when the content of MgO is too large, the devitrification resistance tends to decrease.

  CaO, SrO and BaO are components that lower the high temperature viscosity to improve the meltability, formability and bendability. The total amount of CaO, SrO and BaO is preferably 0 to 15%, 0 to 5%, particularly 0 to less than 1%. The content of each of CaO, SrO and BaO is preferably 0 to 12%, 0 to 5%, 0 to 2%, particularly 0 to less than 1%. When the content of CaO, SrO and BaO is too large, the devitrification resistance, the Young's modulus, the crack resistance and the like are easily reduced.

  From the viewpoint of enhancing Young's modulus and crack resistance, the molar ratio MgO / (MgO + CaO + SrO + BaO) is preferably 0.5 or more, 0.7 or more, 0.8 or more, particularly 0.9 or more. "MgO / (MgO + CaO + SrO + BaO)" is a value obtained by dividing the content of MgO by the total amount of MgO, CaO, SrO and BaO.

  Besides the above components, for example, the following components may be added.

B ₂ O ₃ is a component that forms a network of glass, but is a component that reduces Young's modulus and weather resistance. Therefore, the content of B ₂ O ₃ is preferably 0 to 20%, 0 to 10%, 0 to 1%, and particularly 0 to less than 0.1%.

TiO ₂ is a component that enhances the weather resistance, but is a component that colors the glass. Therefore, the content of TiO ₂ is preferably 0 to 0.5%, particularly 0 to less than 0.1%.

ZrO ₂ is a component that enhances Young's modulus and weatherability, but is a component that reduces the devitrification resistance. Therefore, the content of ZrO ₂ is preferably 0 to 0.5%, particularly 0 to less than 0.1%.

As a clarifier, 0.05% to 0.5% of one or more selected from the group of SnO ₂ , Cl, SO ₃ and CeO ₂ (preferably a group of SnO ₂ and SO ₃ ) may be added .

Fe ₂ O ₃ is a component which is inevitably mixed as an impurity into a glass raw material and is a coloring component. Therefore, the content of Fe ₂ O ₃ is preferably 0.5% or less, in particular 0.01 to 0.07%.

V ₂ O ₅ , Cr ₂ O ₃ , CoO ₃ and NiO are coloring components. Thus, the content of each of V ₂ O ₅ , Cr ₂ O ₃ , CoO ₃ and NiO is preferably at most 0.1%, in particular less than 0.01%.

Rare earth oxides such as Nd ₂ O ₃ and La ₂ O ₃ are components that increase the Young's modulus. However, the cost of the raw material itself is high, and when added in large amounts, the devitrification resistance tends to decrease. Therefore, the total amount of the rare earth oxides is preferably 3% or less, 1% or less, 0.5% or less, and particularly 0.1% or less.

From the environmental consideration, it is preferable that the glass composition substantially does not contain As ₂ O ₃ , Sb ₂ O ₃ , PbO, Bi ₂ O ₃ and F. Here, "does not substantially contain" means that although the explicit component is not positively added as a glass component, the case where it is mixed as an impurity is permitted, specifically, the component of the explicit component It indicates that the content is less than 0.05%.

  It is preferable that the glass plate of this invention has the following characteristics.

  The Young's modulus is preferably 80 GPa or more, 85 GPa or more, 90 GPa or more, particularly 95 to 150 GPa. If the Young's modulus is too low, the velocity of the shock wave due to the collision of the scattering pieces will be slow, so the shock wave will spread only in a narrow region, making it difficult to attenuate the collision energy of the scattering pieces.

  The crack resistance is preferably 500 gf or more, 800 gf or more, 1000 gf or more, and particularly preferably 1200 to 5000 gf. When the crack resistance is too low, the glass plate is apt to be scratched, and the scratch and the strength and transparency of the glass plate are easily degraded.

  The degree of crystallinity is preferably 30% or less, 10% or less, 5% or less, 1% or less, in particular 0%, that is, amorphous. When the degree of crystallization is too high, bending workability tends to be reduced.

  The thickness of the glass plate is preferably 15 mm or less, 12 mm or less, 10 mm or less, particularly 8 mm or less, preferably 1.5 mm or more, 3 mm or more, 4 mm or more, 5 mm or more, 6 mm or more, particularly 7 mm or more. When the thickness of the glass plate is too small, it is difficult to secure impact resistance performance. On the other hand, when the thickness of the glass plate is too large, it becomes difficult to thin the window glass, and the visibility tends to be reduced. In addition, the weight of the window glass is increased, and the fuel consumption of the automobile etc. is increased.

  The glass plate of the present invention is a glass plate for producing a glass resin composite by combining and integrating with a resin plate. In the glass resin composite, it is preferable that a plurality of glass plates be used. In addition, when it has a several glass plate in a glass resin complex, although you may include glass plates (for example, soda glass plate) other than the glass plate of this invention, a viewpoint which enjoys the effect of this invention exactly Therefore, it is preferable that all the glass plates are the glass plates of the present invention.

  In the glass resin composite, although a plurality of resin plates may be used, it is preferable that the number of resin plates is one in terms of enhancing the visibility. As the resin plate, various resins such as acryl and polycarbonate can be used, but polycarbonate is particularly preferable from the viewpoint of transparency, impact relaxation property and weight reduction.

  The thickness of the resin plate is preferably 10 mm or less, 8 mm or less, 7 mm or less, 6 mm or less, particularly 5 mm or less, preferably 0.5 mm or more, 0.7 mm or more, 1 mm or more, 2 mm or more, particularly 3 mm or more . When the thickness of the resin plate is too small, it is difficult to reduce the impact when the scattering pieces collide. On the other hand, when the thickness of the resin plate is too large, it becomes difficult to thin the window glass, and the visibility of the window glass tends to decrease.

  In the glass resin composite, it is preferable that the glass plates, and the glass plate and the resin plate be compositely integrated by the organic resin intermediate layer. The thickness of the organic resin intermediate layer is preferably 0.1 to 2 mm, 0.3 to 1.5 mm, 0.5 to 1.2 mm, and particularly 0.6 to 0.9 mm. If the thickness of the organic resin intermediate layer is too small, the energy of the shock wave is likely to propagate to the indoor side when the scattered pieces collide. On the other hand, when the thickness of the organic resin intermediate layer is too large, the visibility of the window glass tends to decrease.

  The thermal expansion coefficient of the organic resin intermediate layer is preferably not less than the thermal expansion coefficient of the glass plate and not more than the thermal expansion coefficient of the resin plate. In this way, when the window glass is heated by direct sunlight, the glass plate and the resin plate are hardly separated and deformed. In addition, "thermal expansion coefficient" points out the mean linear thermal expansion coefficient in the temperature range of 0-300 degreeC.

  Various organic resins can be used as the organic resin intermediate layer. For example, polyethylene (PE), ethylene vinyl acetate copolymer (EVA), polypropylene (PP), polystyrene (PS), methacrylic resin (PMA), poly Vinyl chloride (PVC), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), cellulose acetate (CA), diallyl phthalate resin (DAP), urea resin (UP), melamine resin (MF), unsaturated polyester (UP) Polyvinyl butyral (PVB), polyvinyl formal (PVF), polyvinyl alcohol (PVAL), vinyl acetate resin (PVAc), ionomer (IO), polymethylpentene (TPX), vinylidene chloride (PVDC), polysulfone (PSF), Poly Vinylidene fluoride (PVDF), methacryl-styrene copolymer resin (MS), polyarete (PAR), polyallyl sulfone (PASF), polybutadiene (BR), polyether sulfone (PESF), or polyether ether ketone (PEEK), etc. Is available. Among them, EVA and PVB are preferable from the viewpoint of transparency and adhesion, and PVB is particularly preferable because it can provide sound insulation.

  A coloring agent may be added to the organic resin interlayer, or an absorber that absorbs light of a specific wavelength such as infrared light or ultraviolet light may be added.

  For the organic resin intermediate layer, a combination of a plurality of the above organic resins may be used. For example, when two organic resin interlayers are used for the composite integration of the glass plate and the resin plate, the glass plate and the resin plate are fixed by different organic resins, so that the warp of the window glass can be easily reduced.

  The total plate thickness of the glass resin composite is preferably 55 mm or less, 45 mm or less, or 40 mm or less, preferably 4 mm or more, 5 mm or more, 7 mm or more, and particularly 10 mm or more. When the total plate thickness of the glass resin composite is too small, the impact resistance performance of the window glass tends to deteriorate. On the other hand, when the total plate thickness of the glass resin composite is too large, the weight of the window glass becomes heavy, and the visibility of the window glass tends to decrease.

  A glass plate can be produced as follows.

  First, a glass raw material prepared so as to obtain a predetermined glass composition is charged into a continuous melting furnace, heated and melted at 1500 to 1700 ° C., clarified and stirred, and then supplied to a forming apparatus to be formed into a plate shape By cooling, a glass plate can be produced.

  As a method of forming a glass plate, it is preferable to adopt a float method. The float method is a method by which a glass plate can be produced inexpensively.

  Besides the float method, the overflow down draw method may be employed. The overflow down draw method is a method capable of producing a large amount of thin glass plates in a state where the surface is unpolished. In addition, the manufacturing cost of a glass plate can be reduced as the surface is unpolished.

  The glass plate is preferably chamfered, if necessary. In that case, it is preferable to perform the C-chamfering process using a # 800 metal bond grindstone or the like. In this way, the end face strength can be increased. If necessary, it is also preferable to etch the end face of the glass plate to reduce the crack source present on the end face.

  Next, curved surface processing is performed about the obtained glass plate as needed. Various methods can be adopted as a method of curved surface processing. In particular, a method of press-molding one by one or laminating glass plates with a mold is preferable, and it is preferable to pass through a heat treatment furnace while sandwiching the glass plate with a mold having a predetermined shape. In this way, it is possible to improve the dimensional accuracy of the curved surface shape. Also, after arranging the glass plates one by one or laminating them on a mold having a predetermined shape, the glass plate is softened by its own weight according to the shape of the mold by heat treating a part or the whole of the glass plate. A method of deformation is also preferred. In this way, the efficiency of curved surface processing can be increased.

  Next, the glass plate (preferably, a plurality of glass plates) and the resin plate may be combined and integrated by the organic resin intermediate layer to produce a glass resin complex. As a method of composite integration, a method of curing an organic resin after pouring an organic resin between glass plates or between a glass plate and a resin plate, pressure heating after arranging an organic resin sheet between glass plates or a glass plate and a resin plate The method of processing (thermocompression bonding) etc. are mentioned. The former method can suppress the deformation of the resin plate due to the expansion mismatch between the glass plate and the resin plate. The latter method is easier for complex integration.

  In addition, after complex integration, a functional film such as a hard coat film, an infrared ray reflective film, or a heat ray reflective film may be formed on the outer surface of the outermost glass plate. Moreover, you may form functional films, such as a hard-coat film, an infrared reflective film, a heat ray reflective film, on the inner surface of the glass plate of the outermost layer, before carrying out composite integration.

  Hereinafter, the present invention will be described in detail based on examples. The following embodiments are merely illustrative. The present invention is not limited at all to the following examples.

  Table 1 shows Examples of the present invention (Sample Nos. 1 to 6) and Comparative Examples (Sample Nos. 7 to 9).

The glass plate was produced as follows. The glass raw materials were compounded so that the glass plate described in Table 1 could be obtained. Next, the prepared glass batch is charged into a continuous melting furnace, melted at 1600 ° C. for 20 hours, then clarified and stirred to obtain a homogeneous molten glass, and then it is formed into a plate having a plate thickness of 8.0 mm. Molded. The Young's modulus, the crack resistance, the glass transition temperature and the degree of crystallinity of the obtained glass plate were evaluated. Sample No. The glass plate according to 1 to 6 has a mixed impurity amount of Fe ₂ O ₃ of 0.05 mol%, and a mixed impurity amount of V ₂ O ₅ , Cr ₂ O ₃ , CoO ₃ and NiO is 0.01 mol each. It was less than%.

  Young's modulus is a value measured by a known resonance method.

  Crack resistance is a load at which the crack incidence rate becomes 50%. The crack generation rate was measured as follows. First, in a constant temperature and humidity chamber maintained at a humidity of 30% and a temperature of 25 ° C., a Vickers indenter set to a predetermined load is driven on a glass surface (optically polished surface) for 15 seconds, and 15 seconds later, it is generated from four corners of the indentation. Count the number of cracks (up to 4 per indentation). Thus, the indenter was driven 20 times and the total number of cracks was determined, and then the total number of cracks / 80 was determined by the formula of 100.

  The glass transition temperature is a value measured using a dilatometer.

  The degree of crystallinity is calculated by measuring the area of the halo corresponding to the mass of the amorphous and the area of the peak corresponding to the mass of the crystal by measuring XRD by the powder method, and then [area of the peak] × The value is obtained by the formula of 100 / [area of peak + area of halo] (%).

  As can be seen from Table 1, the sample Nos. 1 to 6 have high Young's modulus, low glass transition temperature and low crystallinity, and therefore have high impact resistance performance and are easy to be bent. Therefore, sample no. 1 to 6 are considered to be suitable as a glass plate for producing a glass resin composite by being combined with a resin plate. On the other hand, for sample no. 7 to 9 are considered to have low impact resistance performance because of low Young's modulus.

  Next, for sample no. By passing the heat treatment furnace while holding the glass plate according to 1 between molds of a predetermined shape, a curved surface in which the whole in the plate width direction is curved like an arc and the whole along the length is curved like an arc Curved to a shape. Thereafter, C-chamfering and polishing were performed on the end face of the glass plate after curved surface processing using a # 800 metal bond grindstone.

  Subsequently, a polycarbonate plate (plate thickness 4.0 mm) having a curved surface shape similar to that of the glass plate was prepared.

  Finally, from the outside (atmosphere side), sample no. Glass plate according to No. 1 (glass plate of outer layer), polyvinyl butyral (PVB) having a thickness of 0.8 mm, sample no. Sample No. 1 was compounded and integrated by autoclaving so that the glass plate according to No. 1 (glass plate of the inner layer), polyvinyl butyral (PVB) having a thickness of 0.8 mm, and the polycarbonate plate were in this order. A glass resin composite according to 1 was obtained. Sample No. The same experiment is performed for samples 2 to 6, and sample Nos. The glass resin complex which concerns on 2-6 was obtained.

  The glass plate of the present invention is suitable as a glass plate for producing a glass resin composite by being integrated integrally with a resin plate, and the glass resin composite is suitable for window glass of automobiles, railways, aircrafts, etc. Besides, it is also suitable for window glass of buildings such as high-rise buildings.

10 glass resin complex 11 glass plate 12 glass plate 13 resin plate

Claims (6)

It is a glass plate for producing a glass resin composite by combining and integrating with a resin plate,
Glass composition containing 45 to 80% of SiO ₂ , 5 to 30% of Al ₂ O ₃ , 0 to 20% of Li ₂ O + Na ₂ O + K ₂ O, 3 to 35% of MgO, 0 to 15% of CaO + SrO + BaO in mol% Glass plate characterized by   The glass plate according to claim 1, wherein Young's modulus is 80 GPa or more.   The glass plate according to claim 1 or 2, wherein the crack resistance is 800 gf or more.   The glass plate according to any one of claims 1 to 3, which has a crystallinity of 30% or less.   The plate thickness is 3-15 mm, The glass plate in any one of the Claims 1-4 characterized by the above-mentioned.   The glass sheet according to any one of claims 1 to 5, which has a three-dimensionally curved curved surface shape.