Arc-shaped microcrystalline glass plate as well as preparation method and application thereof

Abstract

The invention relates to the technical field of arc-shaped microcrystalline panels, in particular to an arc-shaped microcrystalline glass plate and a preparation method and application thereof. The roughness of the inner and outer surfaces of the arc-shaped microcrystalline glass plate is less than or equal to 0.06 mu m; the radial unevenness A of the arc-shaped microcrystalline glass plate is less than or equal to 0.4%, and A = h / L * 100%; the axial unevenness B of the arc-shaped microcrystalline glass plate is less than or equal to 0.4%, and B = d / L * 100%. The arc-shaped microcrystalline glass plate provided by the invention has a flat and smooth surface, can avoid optical scattering, meets the visibility requirement, and has the advantages of good flatness, low radial unevenness and axial unevenness, no warping angle phenomenon and obvious visual distortion.

Description

Technical Field

[0001] The present invention relates to the technical field of curved microcrystalline panels, and in particular to a curved microcrystalline glass plate and a preparation method and application thereof. Background Art

[0002] The main crystalline phase composition of LAS glass-ceramics (hereinafter referred to as glass-ceramics) is the Li2O-Al2O3-SiO2 system. With its low expansion, high strength, and adjustable light transmittance, it is widely used in various heating fields, especially in scenes such as stove tops and kitchen appliance covers, which are the main application areas of glass-ceramics. The mainstream glass-ceramics preparation technology is the preparation of flat glass-ceramics by molten glass calendering. Glass-ceramics can be divided into colored glass-ceramics, transparent glass-ceramics, and white glass-ceramics according to its body color properties. Among them, the visible light transmittance of the 4mm thick glass-ceramics panel prepared from transparent glass-ceramics can reach more than 70%, and it has the characteristics of low expansion, high strength, and good chemical stability. It is an ideal material for high-temperature observation windows, fireplaces, etc. Limited by the production process of calendering molding, in order to adapt to the flat glass-ceramics panel, the early fireplace design was mainly square. With the birth of the cylindrical fireplace design, its appearance is novel and unique, and the manufacture of the matching curved glass-ceramics panel is particularly critical. In order to enhance visibility, curved microcrystalline panels often require both sides to be smooth and flat, that is, the roughness Ra is required to be ≤ 0.06μm to avoid optical scattering. In addition, curved microcrystalline panels are generally loaded in a specific metal frame in actual applications, and the dimensional tolerance and flatness requirements are relatively strict.

[0003] The existing production process of curved microcrystalline panels is generally gravity molding. That is, first prepare a concave mold, place the flat base glass (base glass refers to the uncrystallized microcrystalline panel) panel horizontally in the concave mold, and heat it to the softening temperature for insulation. Under the action of gravity, the base glass plate deforms until it fits the mold to achieve the arc molding effect. Subsequently, the temperature is continued to be increased to crystallize inside the curved plate to obtain curved microcrystalline glass. This method is particularly suitable for small curved microcrystalline panels with a small central angle. Among them, the mold is the key equipment of the gravity molding method. The dimensions of the curved microcrystalline glass, such as the inner radius and tolerance, are directly determined by the mold.

[0004] In actual production, heat-resistant iron-based alloys are mainly used for mold selection. However, the inherent large thermal expansion coefficient of metal materials makes it easy to torsion deformation after repeated thermal cycles, resulting in the same torsion deformation of the arc-shaped microcrystalline plate attached to its inner wall. When inverted, the "warping" phenomenon is very obvious. For example, when the iron-based mold is used to prepare an arc-shaped microcrystalline plate with an inner diameter R (the shape of the iron-based mold is arc-shaped, R refers to the inner diameter of the arc) of 260mm, a central angle of 60°, and a length of 300mm, the radial unevenness is as high as 1.67%. Among them, the radial unevenness A = h / L×100%; when the arc-shaped microcrystalline plate is placed on a horizontal plane with its opening facing downward, three vertices in the arc-shaped microcrystalline plate are in contact with the horizontal plane, and the distance from the other vertex to the horizontal plane is h; L is the length of the arc-shaped microcrystalline plate along the axial direction. That is, for a 300mm long arc-shaped microcrystalline plate, the height of the remaining vertices from the horizontal plane can reach 5mm when inverted, which does not meet the assembly requirements of the fireplace observation window at all.

[0005] In addition, for arc-shaped microcrystalline plates with a central angle greater than 114°, when the length of the microcrystalline original plate exceeds 2R (R is the inner diameter of the arc of the concave mold), it cannot be simply prepared by the concave mold.

[0006] In response to the above problems, the patent with application number DE2001102576 discloses a method for forming a large arc (>114°) microcrystalline plate. In view of the situation that the length of the microcrystalline original plate exceeds the concave mold, the patent discloses a set of forming devices, that is, cylindrical rotating rollers are set at the top of the left and right sides of the concave mold to help the flat microcrystalline original plate to continue to descend and form under the action of gravity. In the softening stage, the base glass in the center softens and falls, continuously driving the base glass on the support bars on both sides of the concave mold to move toward the concave mold, and finally forming an arc shape that falls into the concave mold as a whole. However, the structure of the device is obviously more complicated. At a high temperature of 800 to 900°C, the problems of fixing the rotating roller and keeping it horizontal during the rotation process are obviously difficult to solve easily. In addition, the microcrystalline original plate is always in contact with the support bars and rotating rollers during the softening process, and there is relative movement, which easily forms scratches on the surface of the microcrystalline original plate. These scratches need to be removed by adding a polishing process, but the polishing of curved glass is much more complicated than that of flat glass. In addition, the inherent small batch and multi-specification characteristics of curved glass products make the process path of forming first and then polishing extremely uneconomical. In addition, this solution is difficult to overcome the problem of twisting of the microcrystalline original plate during the softening process. Various disturbances in the production process can easily cause the microcrystalline original plate to rotate at a small angle when it falls, resulting in high radial unevenness. For this reason, it is necessary to add a cutting process in the future to trim the arc prepared by the above method so that the four vertices are on the same horizontal plane.

[0007] Furthermore, the above patents and existing applications do not mention the axial flatness B, where B = d / L × 100%, L is the length of the curved microcrystalline plate in the axial direction; when the curved microcrystalline plate is placed on a horizontal plane with its opening facing downward, the maximum distance between the curved arc formed by the downward bending of the top of the curved microcrystalline plate and the line connecting the midpoints of the two curved edges of the curved microcrystalline plate is d. In fact, during the crystallization process, the original microcrystalline plate is very likely to form an inward arch along the axial direction. Although this deformation does not affect the assembly of the curved microcrystalline glass panel in applications such as fireplaces, there is a significant visual distortion near the curved edge, so the axial flatness B also needs to be controlled at a lower level.

[0008] In order to achieve a smooth, distortion-free surface of the curved microcrystalline panel, with excellent flatness and adaptability to tooling, conventional preparation methods often require complicated subsequent processing procedures to further polish or cut the formed curved microcrystalline glass to the designed size.

[0009] In view of this, the present invention is proposed. Summary of the invention

[0010] The first purpose of the present invention is to provide a curved microcrystalline glass plate, which has a flat and smooth surface, and the inner and outer surface roughness Ra is ≤0.06μm, which can avoid optical scattering, meet the visibility requirements, and has good flatness, low radial and axial unevenness, no "warping" phenomenon, and no obvious visual distortion of the arc edge. The problem that the curved microcrystalline panel in the prior art is difficult to meet the double-sided roughness ≤0.06μm and the radial flatness and axial flatness are poor is solved.

[0011] The second purpose of the present invention is to provide a method for preparing a curved microcrystalline glass plate, which adopts the steps of first polishing and then forming and crystallizing. It can be formed in one time to directly obtain the required curved microcrystalline panel with a smooth surface and excellent flatness, without the need for subsequent mechanical processing, such as polishing, trimming, chamfering, etc. of the curved panel.

[0012] The third object of the present invention is to provide application of the curved microcrystalline glass plate in the fields of architecture and decoration.

[0013] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0014] The present invention first provides a curved microcrystalline glass plate, wherein the roughness of the inner surface of the curved microcrystalline glass plate is ≤0.06 μm, and the roughness of the outer surface of the curved microcrystalline glass plate is ≤0.06 μm;

[0015] The shape of the curved glass-ceramic plate is an arc;

[0016] The radial unevenness A of the arc-shaped microcrystalline glass plate is ≤0.4%, wherein A=h / L×100%; when the arc-shaped microcrystalline glass plate is placed on a horizontal plane with its opening facing downward, three vertices of the arc-shaped microcrystalline glass plate are in contact with the horizontal plane, and the distance between another vertex and the horizontal plane is h; L is the length of the arc-shaped microcrystalline glass plate in the axial direction; the units of h and L are the same;

[0017] The axial unevenness B of the curved microcrystalline glass plate is ≤0.4%, wherein B=d / L×100%; when the curved microcrystalline glass plate is placed on a horizontal plane with its opening facing downward, along the axial direction of the curved microcrystalline glass plate, the top end of the curved microcrystalline glass plate bends downward to form a curved arc, and the maximum distance between the curved arc and the line connecting the midpoints of the two curved edges of the curved microcrystalline glass plate is d; L is the length of the curved microcrystalline glass plate along the axial direction; the units of d and L are the same.

[0018] Furthermore, the thermal expansion coefficient of the curved microcrystalline glass plate at a temperature of 40 to 700° C. is less than 0.5 ppm / ° C.

[0019] The present invention further provides a method for preparing the curved glass-ceramic plate, comprising the following steps:

[0020] Obtaining a double-sided polished flat microcrystalline original plate;

[0021] The double-sided polished flat microcrystalline original plate is placed on a refractory material mold and then subjected to heat treatment for molding and crystallization to obtain the curved microcrystalline glass plate.

[0022] Furthermore, the vertices of the double-sided polished flat microcrystalline original plate are chamfered and / or rounded, and the four sides of the double-sided polished flat microcrystalline original plate are chamfered and / or rounded.

[0023] Furthermore, the material of the flat-plate microcrystalline original plate includes LAS microcrystalline glass.

[0024] Furthermore, the refractory material in the refractory material mold includes at least one of a zirconium refractory material, a corundum refractory material, a magnesia refractory material, a calcium-magnesium refractory material and a silicon refractory material.

[0025] Furthermore, the thickness of the refractory material mold is ≤15 mm.

[0026] Furthermore, the roughness of the inner surface of the refractory material mold is 0.05-4.00 μm.

[0027] Furthermore, the central angle of the arc-shaped glass-ceramic plate is greater than 114°.

[0028] Further, the shape of the refractory mold is an arc; the refractory mold is respectively connected with auxiliary side edges on two sides along the axial direction thereof, the auxiliary side edges are in the shape of a flat plate, the refractory mold is fixedly connected or detachably connected to the two auxiliary side edges, and when the refractory mold is placed with the opening facing upward, the angle α between the auxiliary side edges and the horizontal plane satisfies: α>(21750-2490000 / θ) 1 / 2 , where θ is the central angle of the arc-shaped micro-ceramic glass plate, in degrees.

[0029] The present invention also provides application of the curved microcrystalline glass plate in the fields of architecture and decoration.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The curved microcrystalline glass plate provided by the present invention has a flat and smooth surface and good flatness.

[0032] (2) The curved glass-ceramic plate provided by the present invention has no scratches on the surface.

[0033] (3) The arc-shaped microcrystalline glass plate provided by the present invention has a central angle greater than 114° and a low thermal expansion coefficient.

[0034] (4) The method for preparing the curved microcrystalline glass plate provided by the present invention comprises first polishing and then forming and crystallizing, so as to obtain a low-expansion curved microcrystalline glass plate with a flat and smooth surface and good flatness.

[0035] (5) The method for preparing the curved microcrystalline glass plate provided by the present invention is to polish first and then form and crystallize, which has high production efficiency and high yield. In addition, the method of polishing first is used to industrially polish the flat plate, which has high polishing quality and high polishing efficiency. In addition, the plate surface is basically not broken during the polishing process, and the plate loss is small.

[0036] (6) The method for preparing the curved microcrystalline glass plate provided by the present invention uses refractory materials to replace traditional metal alloy materials to manufacture molds. The refractory material mold can be used for a long time without deformation and can be recycled many times.

[0037] (7) The method for preparing the curved microcrystalline glass plate provided by the present invention can prepare a curved microcrystalline plate with a central angle greater than 114° by respectively setting auxiliary side edges on both sides of the mold.

[0038] (8) The method for preparing the curved microcrystalline glass plate provided by the present invention can improve the axial flatness of the curved microcrystalline glass plate by controlling the thickness of the refractory material mold.

[0039] (9) The method for preparing the curved microcrystalline glass plate provided by the present invention can ensure that no scratches are generated on the surface of the microcrystalline original plate during the falling process by controlling the angle α between the auxiliary side and the horizontal plane, thereby ensuring that the surface of the curved microcrystalline glass plate is free of scratches. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 A schematic diagram of the structure of a curved glass-ceramic plate provided by the present invention;

[0042] Figure 2 A schematic diagram of the structure of the curved glass-ceramic plate provided by the present invention when the opening is placed downward;

[0043] Figure 3 Another schematic diagram of the structure of the curved glass-ceramic plate provided by the present invention when the opening is placed downward;

[0044] Figure 4 A schematic structural diagram of a refractory material mold with auxiliary side edges provided by the present invention;

[0045] Figure 5 A schematic diagram of the structure in which a double-sided polished flat microcrystalline original plate is horizontally placed on a refractory material mold in Example 1 provided by the present invention;

[0046] Figure 6 A linear expansion coefficient curve diagram of the curved microcrystalline panel obtained in Example 1 provided by the present invention;

[0047] Figure 7 This is a visible light transmittance curve of the curved microcrystalline panel prepared in Example 1 provided by the present invention. DETAILED DESCRIPTION

[0048] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0049] If there is no special explanation, in the present invention, "the first aspect", "the second aspect", "the third aspect", "the fourth aspect", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "the first", "the second", "the third", "the fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0050] If there is no special explanation, the "include" and "comprising" mentioned in the present invention represent open-ended or closed-ended expressions. For example, the "include" and "comprising" may represent that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0051] If there is no special explanation, in the present invention, "one or more" or "at least one" refers to any one, any two or more of the listed items. Among them, "several" refers to any two or more of the listed items.

[0052] In a first aspect, the present invention provides a curved microcrystalline glass plate, the roughness of the inner surface of the curved microcrystalline glass plate is ≤0.06μm, including but not limited to any point value of 0.05μm, 0.04μm, 0.03μm, 0.02μm, 0.01μm or a range value between any two of them; the roughness of the outer surface of the curved microcrystalline glass plate is ≤0.06μm, including but not limited to any point value of 0.05μm, 0.04μm, 0.03μm, 0.02μm, 0.01μm or a range value between any two of them.

[0053] See also Figure 1As shown, the shape of the curved microcrystalline glass plate is an arc, or an arch. It can be understood that the curved microcrystalline glass plate includes two curved edges and two straight edges, and the curved microcrystalline glass plate includes four vertices, i.e., the intersections of the curved edges and the straight edges, wherein the vertices can be right angles, chamfers, or rounded corners, preferably chamfers or rounded corners, i.e., the curved edges and the two straight edges are trimmed to be chamfers or rounded corners.

[0054] The radial roughness A of the arc-shaped microcrystalline glass plate is ≤ 0.4%, including but not limited to any point value of 0.35%, 0.3%, 0.25%, 0.2%, 0.15%, 0.1%, 0.05% or any range value between two of them. Wherein, A = h / L × 100%. See Figure 2 As shown, when the curved microcrystalline glass plate is placed on a horizontal plane with its opening facing downward (the curved side is in an n-shape at this time), three vertices of the curved microcrystalline glass plate are in contact with the horizontal plane, and the distance between another vertex and the horizontal plane is h; L is the length of the curved microcrystalline glass plate in the axial direction. Wherein, h and L have the same unit.

[0055] The axial roughness B of the arc-shaped microcrystalline glass plate is ≤ 0.4%, including but not limited to any point value of 0.35%, 0.3%, 0.25%, 0.2%, 0.15%, 0.1%, 0.05% or any range value between two of them. Wherein, B = d / L × 100%. See Figure 3 As shown, when the curved microcrystalline glass plate is placed on a horizontal plane with its opening facing downward (the curved edge is n-shaped at this time), along the axial direction of the curved microcrystalline glass plate, the top end of the curved microcrystalline glass plate bends downward to form a curved arc (that is, the outer side of the top end of the curved microcrystalline glass plate is concave), and the maximum distance between the curved arc and the line connecting the midpoints of the two curved edges of the curved microcrystalline glass plate is d; L is the length of the curved microcrystalline glass plate along the axial direction; wherein, the units of d and L are the same.

[0056] In some specific implementations, a straight line is drawn at the midpoint of the two curved sides of the curved microcrystalline glass plate, or a calibrated straight metal tube is placed, so that the two ends of the metal tube are respectively in contact with the midpoints of the two curved sides of the curved microcrystalline glass plate. Since the top of the curved microcrystalline glass plate is concave downward, there is a certain distance between the concave part and the straight line or the metal tube, and the maximum gap between the concave part and the straight line or the metal tube is d. This spacing d can be measured by a feeler gauge that complies with GB / T 22523. The feeler gauge is a prefabricated steel sheet, wherein the thickness of the steel sheet is an integer multiple of 0.05 mm, such as 0.05 mm, 0.10 mm, 0.15 mm, etc.

[0057] The curved microcrystalline glass plate provided by the present invention has a flat and smooth surface, and the roughness of both the inner and outer surfaces is ≤0.06 μm, which can avoid optical scattering and has good flatness.

[0058] In the present invention, the roughness is measured using Mitutoyo SJ-210 according to ISO 1997 method, and λc is set to 2.5.

[0059] In some specific embodiments, the thermal expansion coefficient of the curved microcrystalline glass plate at a temperature of 40 to 700°C is less than 0.5ppm / °C. The curved microcrystalline glass plate provided by the present invention has the advantage of low expansion and can withstand an instantaneous temperature difference of up to 750°C, that is, the curved microcrystalline glass plate is placed in a muffle furnace at 780°C and kept at a constant temperature for at least 30 minutes, and immediately put into room temperature water after being taken out, completely immersed, not broken, and without visible cracks.

[0060] In a second aspect, the present invention provides a method for preparing the curved glass-ceramic plate, comprising the following steps:

[0061] First, a double-sided polished flat microcrystalline original plate is obtained.

[0062] Among them, the microcrystalline original plate refers to the glass plate that is rolled into a flat shape after being melted in a glass melting furnace. It is not crystallized and can also be called basic glass.

[0063] Then the double-sided polished flat microcrystalline original plate is placed on a refractory mold and placed in a heating furnace for heat treatment to form and crystallize the original plate, and the curved microcrystalline glass plate is obtained after cooling. The refractory mold does not deform at high temperatures.

[0064] It is understood that during the heat treatment process, the double-sided polished flat microcrystalline original plate is heated and softened, and under the action of gravity, the center of gravity of the microcrystalline original plate continues to drop, and finally clings to the refractory mold to form an arc. Among them, the temperature, time and heating rate of the heat treatment can adopt any parameters commonly used in the art, and the present invention is not limited to this.

[0065] The preparation method of the curved microcrystalline glass plate provided by the present invention adopts the steps of first polishing and then forming and crystallizing, which can effectively control the roughness of the inner and outer surfaces of the curved microcrystalline glass plate to be ≤0.06μm, and the roughness hardly changes before and after heat treatment. The low-expansion curved microcrystalline glass plate prepared by this method has a smooth surface, good flatness, and no scratches on the surface.

[0066] The preparation method of the curved microcrystalline glass plate provided by the present invention is to polish first and then form and crystallize, which can save work time. In addition, by adopting the method of polishing first, it is very easy to industrially polish the flat plate, the breakage rate in the polishing process is low, and the polishing quality is high.

[0067] At the same time, the preparation method of the curved microcrystalline glass plate provided by the present invention is simple, and is formed in one step without subsequent grinding, cutting, polishing and other processes.

[0068] In addition, the present invention uses refractory materials to replace traditional metal alloy materials to manufacture molds. The molds made of refractory materials can be used for a long time without deformation and can be recycled many times, thus solving the problem that the existing technology using metal materials is prone to "warping corners".

[0069] In some specific embodiments, the vertices of the double-sided polished flat microcrystalline original plate are chamfered and / or rounded.

[0070] In some specific embodiments, the four edges of the double-sided polished flat microcrystalline original plate are trimmed to be chamfered and / or rounded.

[0071] That is, the appearance requirements of the corners and edges of the flat microcrystalline original plate require corresponding machining treatment when preparing the microcrystalline original plate.

[0072] In some specific embodiments, the method for obtaining a double-sided polished flat microcrystalline original plate includes: calculating the size of the flat microcrystalline original plate corresponding to the curved microcrystalline glass plate, taking into account the volume shrinkage during the crystallization process, the size of the flat microcrystalline original plate is preferably slightly larger than the final curved microcrystalline glass plate product size. Take a larger flat microcrystalline original plate, polish it on both sides, and cut it to the designed flat plate size. It is understandable that it can be polished first and then cut, or it can be cut first and then polished. Then trim the four edges so that the ends of the four edges are chamfered or rounded.

[0073] In some specific implementations, the double-sided polished flat microcrystalline original plate is placed horizontally, and a level meter can be used to calibrate the horizontal placement of the double-sided polished flat microcrystalline original plate.

[0074] In some specific embodiments, the material of the flat-type microcrystalline original plate includes LAS microcrystalline glass (i.e., a flat-type LAS microcrystalline glass original plate), but is not limited to this. The preparation method of the curved microcrystalline glass plate provided by the present invention can also be applied to other types of microcrystalline glass panels that need to be prepared into a curved shape.

[0075] Among them, the flat LAS microcrystalline glass original plate, that is, the basic glass without crystallization, has a glass transition point of about 700°C, while the microcrystalline glass after crystallization has a glass transition point of more than 900°C, that is, the softening temperature is also more than 900°C, so it is difficult to crystallize the LAS microcrystalline glass first and then bend it into shape.

[0076] In some specific implementations, the heat treatment specifically includes: preheating first, then softening and nucleation, and then crystallization.

[0077] In some specific embodiments, during the preheating process, the heating rate is 2 to 30 K / min, and the temperature of the heating furnace is raised from room temperature to the softening temperature Ts of the flat microcrystalline original plate. The heating rate can be as high as possible while ensuring that the flat microcrystalline original plate and the refractory mold do not break due to thermal expansion.

[0078] In some specific embodiments, during the softening and nucleation process, an arc-shaped microcrystalline original plate is formed. Among them, the softening temperature Ts is 20 to 110°C above the Tg point (glass transition point), generally 710 to 820°C, and the temperature is kept for 10 to 60 minutes. The softening process can be constant temperature or warming. The total insulation time varies depending on the difficulty of forming the microcrystalline panel. The arc-shaped plate with a larger central angle is more obviously affected by gravity, and the time required for softening may be shorter. If the Ts temperature is too low, the glass viscosity is large, the gravity falls slowly, and it takes too long, and it may even bend out of place. If Ts is too large, it is easy to cause crystal growth and increase the crystallinity. The significant effect of increased crystallinity is that the viscosity increases, and the glass is difficult to soften and deform, which also leads to bending out of place. Here, bending out of place refers to the final formed microcrystalline panel, the lowest point on the outer side of the arc surface is more than 1mm away from the inner surface of the mold, and there is a gap that is obvious to the naked eye. The temperature of this step is lower than Tc and higher than Tg, so the softening temperature generally coincides with the nucleation temperature, and nucleation is completed during the softening process. The softening process can achieve good axial flatness, that is, the curved microcrystalline original plate formed after high-temperature softening can usually fit the mold tightly.

[0079] In some specific embodiments, a curved microcrystalline glass plate is formed after the crystallization. During the crystallization process, the temperature continues to rise to the crystallization temperature Tc, and the heating rate is 2 to 15K / min. The Tc temperature is generally in the range of -30 to +100°C of the Tp point temperature. The Tp temperature is obtained by measuring the thermal effect of the microcrystalline original plate, and conventional detection equipment such as DSC and DTA detection are used. The Tc temperature is kept for 10 to 45 minutes, and crystal growth is achieved in this process. The temperature range for crystallization of LAS microcrystalline glass is relatively wide, and crystallization can be achieved not only in the Tc insulation stage, but also in the heating stage before crystallization. Generally, the set maximum temperature is Tp point temperature -30 + 100°C, which is called the crystallization temperature Tc, and the temperature is kept warm. The heating rate can be 1 to 15K / min, and the maximum value of the heating rate is limited to not causing the microcrystalline glass and refractory mold to break. The holding time is 10 to 45 minutes. Too long a holding time or too high a holding temperature will cause the high quartz crystal phase to transform into the hydrothermal quartz crystal phase, thereby significantly increasing the expansion coefficient. Too short a holding time or too low a holding temperature will result in insufficient crystallization and fail to meet the low expansion performance requirements.

[0080] In some specific embodiments, the refractory material used in the refractory mold includes at least one of a zirconium refractory material, a corundum refractory material, a magnesia refractory material, a calcium-magnesium refractory material and a silicon refractory material.

[0081] In some specific embodiments, the thickness of the refractory mold is ≤15mm, including but not limited to any point value of 14mm, 13mm, 12mm, 11mm, 10mm, 8mm, 6mm, 5mm, 3mm, 2mm or any range value between two of them; preferably 2 to 15mm. Refractory materials have extremely poor thermal conductivity. When a refractory mold is made, if the temperature difference in the transverse direction (with the axial direction of the arc-shaped microcrystalline plate as the transverse direction) is large, when the volume shrinks during the crystallization process, it will cause deformation along the axial direction and form an arch toward the center of the circle. The inventors found that the thinner the thickness, the smaller the lateral temperature difference of the refractory mold, and the better the flatness of the microcrystalline panel, especially the axial flatness. However, refractory molds with a thickness of less than 2mm face greater challenges in the mold preparation process, are easily broken during use, and are also easily broken during processing. Therefore, the present invention controls the temperature uniformity of the refractory mold to be better when the thickness of the refractory mold is less than 15mm, and the axial unevenness of the refractory mold and the obtained arc-shaped microcrystalline glass plate can be controlled. The problem that the prior art does not consider the axial flatness, resulting in obvious visual distortion near the curved edge, is solved.

[0082] In some specific implementations, the maximum thickness of the refractory material mold is ≤15 mm.

[0083] In some specific embodiments, the thickness of the refractory mold is different at different bends, the thickness at the center of the refractory mold is greater than the thickness at both ends, and the center of the refractory mold (the bottom end when the opening is placed upward) has the largest thickness, see Figure 4 As shown, the thickness at both ends is slightly less than that at the center.

[0084] In some specific implementations, thinner refractory molds are prone to breakage during mold processing or crystallization. In this case, an auxiliary method can be used, that is, two side brackets are designed outside the refractory mold to reduce the phenomenon of breakage during mold processing or crystallization.

[0085] In some specific embodiments, the roughness of the inner surface of the refractory mold is 0.05 to 4.00 μm, including but not limited to any point value of 0.05 μm, 0.10 μm, 0.20 μm, 0.30 μm, 0.50 μm, 0.80 μm, 1.00 μm, 2.00 μm, 3.00 μm, 4.00 μm or any range value between two of them. The present invention uses a polished microcrystalline original plate, which is easy to adsorb with the glass phase in the refractory material during the crystallization process, resulting in damage to the surface of the microcrystalline panel, and increasing the roughness of the inner surface of the refractory mold can avoid this problem. However, the roughness of the inner surface of the refractory mold should not be too large. If it is too large, small particles on the surface of the refractory mold are easy to fall off during the crystallization process, thereby forming defects such as pits and white spots on the surface of the microcrystalline panel.

[0086] In some specific embodiments, the central angle θ of the curved microcrystalline glass plate is greater than 114°, including but not limited to any point value of 115°, 116°, 118°, 120°, 130°, 140°, 160° or a range value between any two of them.

[0087] In some specific embodiments, the shape of the refractory material mold is an arc. The refractory material mold is connected to auxiliary side edges on two sides along the axial direction thereof, see Figure 4 As shown, the auxiliary side is in the shape of a plate, and the end of the auxiliary side is connected to the end of the refractory mold, wherein the refractory mold and the two auxiliary side are fixedly connected or detachably connected. When the refractory mold is placed with the opening facing upward, the angle α between the auxiliary side and the horizontal plane satisfies the following relationship: α>(21750-2490000 / θ) 1 / 2 , where θ is the center angle of the arc-shaped microcrystalline glass plate, that is, the center angle of the arc, and the unit is degree (°). This ensures that no scratches are generated on the surface of the microcrystalline original plate during the falling process.

[0088] That is, the auxiliary side can be an integral structure with the refractory material mold, or a separate structure, fixed into a desired structure by an external bracket.

[0089] The present invention can prepare an arc-shaped microcrystalline plate with a central angle greater than 114° by respectively setting auxiliary side edges on both sides of the mold, thereby solving the problem that when the length of the base glass exceeds 2R (R is the arc inner diameter of the concave mold), it is difficult to prepare an arc-shaped microcrystalline plate with a central angle greater than 114° using a conventional concave mold.

[0090] In some specific implementations, after double-sided polishing, the roughness of both surfaces (ie, the upper surface and the lower surface) of the double-sided polished flat microcrystalline original plate is ≤0.06 μm.

[0091] The roughness of the outer surface (the surface in contact with the refractory material mold) and the inner surface of the curved microcrystalline glass plate prepared by the present invention is almost the same as that of the flat microcrystalline original plate, and the heat treatment process hardly causes degradation of the roughness.

[0092] In a third aspect, the present invention provides applications of the curved glass-ceramic plate in the fields of architecture and decoration.

[0093] Among them, the architectural field includes but is not limited to applications in glass curtain walls, wall decoration, etc., and the decorative field includes but is not limited to applications in interior home decoration, artwork production, aquariums and fish tanks, courtyard landscaping, etc.

[0094] The embodiments of the present invention will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. If no specific conditions are specified in the examples, the conditions are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0095] In each embodiment and each comparative example of the present invention, the roughness is measured using Mitutoyo SJ-210 according to the ISO 1997 method, and λc is set to 2.5.

[0096] Example 1

[0097] This embodiment provides a curved microcrystalline panel (i.e., a curved microcrystalline glass plate) with a radius of R=300 mm, a chord height of d=173.2 mm, a length along the axial direction of L=400 mm, and a thickness of 4 mm. The preparation method thereof includes the following steps:

[0098] (1) Take a flat LAS glass-ceramic plate, process it to a thickness of 4.05 mm, and polish it to a roughness of 0.026 μm on both the upper and lower surfaces by double-sided polishing. Then cut it into a rectangle with a size of 696.7 mm × 404 mm, and trim the four edges to make the corners rounded.

[0099] (2) Quartz ceramic refractory material (i.e., siliceous refractory material) is used to make a refractory mold. The shape of the refractory mold is arc-shaped, with a thickness of ≤8mm. The center of the refractory mold (the bottom end when the opening is placed upward) has the largest thickness of 8mm, and the thickness of the remaining parts is slightly less than 8mm. The arc radius of the refractory mold is 304mm, the center angle of the mold is 180°, and the length of the mold in the axial direction is 450mm, which exceeds the length of the microcrystalline original plate (the length in the axial direction is 405mm) by 45mm. The roughness of the inner surface of the refractory mold is 3.86μm.

[0100] The refractory material mold is respectively connected to auxiliary side edges on its two sides along the axial direction. The auxiliary side edges are flat in shape. The two auxiliary side edges have the same shape and size. The auxiliary side edges are the same length as the refractory material mold, which is 450 mm. The width of the auxiliary side edges (i.e., the direction extending outward from the opening of the refractory material mold) is 90 mm. The refractory material mold and the two auxiliary side edges are an integrated structure that is fixedly connected. When the refractory material mold is placed with the opening facing upward, the angle α between the auxiliary side edges and the horizontal plane is 55°.

[0101] (3) The double-sided polished flat microcrystalline original plate obtained in step (1) is placed horizontally on the refractory material mold obtained in step (2), see Figure 5 As shown, it is placed in a heating furnace for heat treatment to be formed and crystallized, and then quickly cooled to room temperature to obtain the curved microcrystalline glass plate, which has an arc shape.

[0102] The heat treatment specifically includes: preheating from room temperature to 720°C, where the heating rate is 15K / min and the heating time is about 46 minutes. Then the temperature is raised to 780°C, the heating time is 30 minutes, and the heating rate is 2K / min to complete the softening and nucleation process. Then the temperature is further raised to 880°C, the heating rate is 5K / min, the heating time is 20 minutes, and the temperature is kept at 880°C for 30 minutes to complete the crystallization.

[0103] The linear expansion coefficient curve of the curved microcrystalline panel prepared in this embodiment is shown in Figure 6 It can be seen that the thermal expansion coefficient of the curved microcrystalline panel prepared in Example 1 at 40-700°C is 0.29 ppm / °C.

[0104] The visible light transmittance curve of the curved microcrystalline panel prepared in this embodiment is shown in Figure 7 It can be calculated that the transmittance of the curved microcrystalline panel prepared in Example 1 in the visible light range (400-700nm) is 86.67%. The transmittance is tested according to the method specified in GB / T 2680-1994, the testing equipment is Hunterlab ColorQuest XE, and the visible light detection wavelength range is 400-700nm.

[0105] Embodiment 2 to Embodiment 3

[0106] The differences between Example 2 and Example 3 and Example 1 are shown in Table 1.

[0107] Embodiment 4 to Embodiment 6

[0108] The differences between Example 4, Example 5 and Example 6 and Example 1 are shown in Table 2.

[0109] Example 7

[0110] The preparation method of the curved microcrystalline panel provided in this embodiment is basically the same as that of Embodiment 1, except that the refractory quartz ceramic refractory material is replaced by a corundum ceramic refractory material (ie, a corundum refractory material).

[0111] The thermal expansion coefficient is related to the heat treatment process. The heat treatment process of Examples 2 to 7 is the same as that of Example 1. Therefore, the thermal expansion coefficient of the curved microcrystalline panels manufactured in Examples 2 to 7 at 40 to 700° C. is substantially the same as that of the curved microcrystalline panel in Example 1.

[0112] Light transmittance is related to the heat treatment process and surface roughness. The heat treatment process of Examples 2 to 7 is the same as that of Example 1, and the surface roughness is basically the same as that of Example 1. Therefore, the visible light transmittance of the curved microcrystalline panels obtained in Examples 2 to 7 is basically the same as that of the curved microcrystalline panel in Example 1.

[0113] Comparative Example 1 to Comparative Example 2

[0114] The differences between Comparative Examples 1 and 2 and Example 1 are shown in Table 1. In which, the maximum thickness of the mold in Comparative Example 1 is 25 mm. α in Comparative Example 2 does not satisfy > (21750-2490000 / θ) 1 / 2 .

[0115] Comparative Example 3 to Comparative Example 4

[0116] The differences between Comparative Examples 3 and 4 and Example 1 are shown in Table 2. The inner surface roughness Ra of the mold in Comparative Example 3 is 0.031 μm. The inner surface roughness Ra of the mold in Comparative Example 4 is 4.045 μm.

[0117] Comparative Example 5

[0118] The method for preparing the curved microcrystalline panel provided in this comparative example is basically the same as that in Example 1, except that, in step (2), a curved iron-based mold (without auxiliary side edges) is used instead of a refractory mold.

[0119] Table 1 Differences in parameters of each group

[0120]

[0121]

[0122] Table 2 Differences in parameters of each group

[0123]

[0124] It can be seen from Table 1 and Table 2 that the surface of the arc-shaped microcrystalline glass plate prepared in each embodiment is flat and smooth, has good flatness, has no surface scratches, has a central angle greater than 114°, and has a low thermal expansion coefficient.

[0125] The maximum thickness of the mold in Comparative Example 1 is 25 mm, which leads to a significant increase in radial and axial unevenness, and higher A and B values.

[0126] α in Comparative Example 2 does not satisfy > (21750-2490000 / θ) 1 / 2 , resulting in multiple scratches on the surface of the curved micro-glass plate.

[0127] The roughness of the inner surface of the mold in Comparative Example 3 is too low, resulting in multiple delaminations on the outer surface of the curved microcrystalline glass plate (the contact surface with the mold). This is because the microcrystalline original plate is adsorbed to the mold, resulting in abnormal molding and failure to fit the mold.

[0128] The inner surface roughness of the mold in Comparative Example 4 is too high, and small particles on the mold surface fall off during the crystallization process, resulting in multiple white spots on the outer surface of the curved microcrystalline glass plate. Such defects must be removed by subsequent mechanical processing, which does not meet the requirement of the present invention that no subsequent processing is required.

[0129] In addition, Comparative Example 5 uses an iron-based mold without auxiliary side edges, resulting in a significant increase in radial unevenness, with a radial unevenness A of 1.70%. In addition, Comparative Example 5 uses an iron-based mold, and a large amount of debris is generated during the heating process due to the inevitable high-temperature oxidation, which exists between the microcrystalline panel and the mold. Although the debris itself is very easy to fall off the surface of the microcrystalline panel, these debris cause small pits to appear on the contact surface between the microcrystalline panel and the mold, and the outer surface roughness is significantly increased.

[0130] Although the present invention has been illustrated and described with specific embodiments, it should be appreciated that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents without departing from the spirit and scope of the present invention. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications within the scope of the present invention are included in the appended claims.

Claims

1. A curved glass-ceramic plate, characterized in that: The roughness of the inner surface of the curved microcrystalline glass plate is ≤0.06 μm, and the roughness of the outer surface of the curved microcrystalline glass plate is ≤0.06 μm; The shape of the curved glass-ceramic plate is an arc; The radial unevenness A of the arc-shaped microcrystalline glass plate is ≤0.4%, wherein A=h / L×100%; when the arc-shaped microcrystalline glass plate is placed on a horizontal plane with its opening facing downward, three vertices of the arc-shaped microcrystalline glass plate are in contact with the horizontal plane, and the distance between another vertex and the horizontal plane is h; L is the length of the arc-shaped microcrystalline glass plate in the axial direction; the units of h and L are the same; The axial unevenness B of the curved microcrystalline glass plate is ≤0.4%, wherein B=d / L×100%; when the curved microcrystalline glass plate is placed on a horizontal plane with its opening facing downward, along the axial direction of the curved microcrystalline glass plate, the top end of the curved microcrystalline glass plate bends downward to form a curved arc, and the maximum distance between the curved arc and the line connecting the midpoints of the two curved edges of the curved microcrystalline glass plate is d; L is the length of the curved microcrystalline glass plate along the axial direction; the units of d and L are the same.

2. The curved glass-ceramic plate according to claim 1, characterized in that: The thermal expansion coefficient of the curved microcrystalline glass plate at a temperature of 40 to 700° C. is less than 0.5 ppm / ° C.

3. The method for preparing the curved glass-ceramic plate according to claim 1 or 2, characterized in that: The steps include: Obtaining a double-sided polished flat microcrystalline original plate; The double-sided polished flat microcrystalline original plate is placed on a refractory material mold and then subjected to heat treatment for molding and crystallization to obtain the curved microcrystalline glass plate.

4. The method for preparing the curved glass-ceramic plate according to claim 3, characterized in that: The apex and four edges of the double-sided polished flat microcrystalline original plate are chamfered and / or rounded.

5. The method for preparing the curved glass-ceramic plate according to claim 3, characterized in that: The material of the flat microcrystalline original plate includes LAS microcrystalline glass.

6. The method for preparing the curved glass-ceramic plate according to claim 3, characterized in that: The refractory material in the refractory material mold includes at least one of a zirconium refractory material, a corundum refractory material, a magnesia refractory material, a calcium-magnesium refractory material and a silicon refractory material.

7. The method for preparing the curved glass-ceramic plate according to claim 3, characterized in that: The thickness of the refractory material mold is ≤15mm; And / or, the roughness of the inner surface of the refractory mold is 0.05-4.00 μm.

8. The method for preparing the curved glass-ceramic plate according to claim 3, characterized in that: The central angle of the arc-shaped micro-ceramic glass plate is greater than 114°.

9. The method for preparing the curved glass-ceramic plate according to claim 8, characterized in that: The shape of the refractory mold is an arc; the refractory mold is connected to auxiliary side edges on two sides along the axial direction thereof, the auxiliary side edges are in the shape of a flat plate, the refractory mold is fixedly connected or detachably connected to the two auxiliary side edges, and when the refractory mold is placed with the opening facing upward, the angle α between the auxiliary side edges and the horizontal plane satisfies: α>(21750-2490000 / θ) 1 / 2 , where θ is the central angle of the arc-shaped microcrystalline glass plate, in degrees.

10. Application of the curved microcrystalline glass plate as claimed in claim 1 or 2 in the fields of architecture and decoration.

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