Glass plate clip

Abstract

The present invention relates to a paper for glass plates. The object of the present invention is to provide a paper for glass plates, which inhibits the adhesion of silicon-containing foreign matter, especially micro-sized silicon dioxide foreign matter, to the surface of a glass plate. The paper for glass plates contains cellulose pulp as a main component, and when the silicon concentration and calcium concentration of the paper for glass plates measured by fluorescent X-ray analysis are respectively X and Y, X is 200 ppm or less, and the value obtained by dividing the silicon concentration by the calcium concentration, that is, the X / Y ratio, is 4.00 or less.

Description

Technical Field

[0001] The present invention relates to a paper interlayer for glass plates, a glass plate laminate and a glass plate package. Background Art

[0002] In glass plates used for flat panel displays (FPDs) such as liquid crystal displays, fine electronic wiring (hereinafter also referred to as "wiring") is formed on the surface of the glass plate, and minute scratches and dirt on the surface cause defects such as disconnection. Therefore, the surface of the glass plate is required to have high cleanliness.

[0003] In order to improve the conveying efficiency, the glass plates are conveyed by overlapping the glass plates. At this time, the glass plates are sandwiched between adjacent glass plates with paper clips (hereinafter, also referred to as "paper clips") to suppress scratches etc. generated on the glass plate surfaces during conveyance.

[0004] However, due to the influence of foreign matter and various chemical substances mixed in the process of manufacturing the paper, foreign matter may be attached to the surface of the glass plate from the paper. Foreign matter attached to the surface of the glass plate is mostly removed by cleaning before the process of forming wiring on the surface of the glass plate, but sometimes remains on the surface of the glass plate after cleaning, causing disconnection, etc. Therefore, there is a need for a paper for glass plates that reduces foreign matter attached to the surface of the glass plate.

[0005] In Patent Document 1, the contamination of the surface of the glass plate is reduced by reducing the concentration of aluminum, silicon, magnesium and the like contained in the paper for glass plates.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-210286 Summary of the invention

[0009] Problems to be solved by the invention

[0010] However, with the recent increase in the definition of displays, the width and pitch of wiring formed on the surface of a glass plate have become finer than before. Therefore, even if a glass plate paper such as that disclosed in Patent Document 1 is used, problems such as disconnection may occur during wiring formation.

[0011] The inventors studied the above problem and found that the cause is that micro-sized silica foreign matter remains on the surface of the glass plate even after cleaning. Micro-sized silica foreign matter is difficult to remove by the cleaning process before forming wiring, so it is important to prevent the micro-sized silica foreign matter from adhering to the surface of the glass plate.

[0012] An object of the present invention is to provide a glass plate paper which suppresses adhesion of micro-sized silica foreign matter to the surface of a glass plate, thereby suppressing the occurrence of a defect such as disconnection during wiring formation.

[0013] Means used to solve problems

[0014] The present invention relates to a glass plate paper, wherein the glass plate paper has cellulose pulp as a main component and the basis weight of the glass plate paper is 10 g / m 2 Above and 100g / m 2 The invention is characterized in that, when the silicon concentration and calcium concentration of the glass plate paper measured by fluorescent X-ray analysis are respectively represented by X and Y, X is 200 ppm or less, and the ratio X / Y obtained by dividing the silicon concentration by the calcium concentration is 4.00 or less.

[0015] When the magnesium concentration of the paper for glass plates measured by fluorescent X-ray analysis is defined as Z, the X / Z ratio, which is a value obtained by dividing the silicon concentration by the magnesium concentration, is preferably 3.00 or less.

[0016] The Z is preferably 20 ppm or more and 100 ppm or less.

[0017] The Y is preferably 20 ppm or more and 400 ppm or less.

[0018] The number of silicon-containing foreign matter with a size of 0.5 μm or more and 50 μm or less present on at least one surface of the paper for a glass plate is preferably 2000 pieces / mm 2 the following.

[0019] The number of silicon-containing foreign matter having a size of 1 μm or more and 10 μm or less existing on at least one surface of the paper for glass plates is preferably 1000 pieces / mm 2 the following.

[0020] The number of silicon dioxide foreign matter with a size of 0.5 μm or more and 50 μm or less present on at least one paper surface of the paper for a glass plate is preferably 100 pieces / mm 2 the following.

[0021] The number of silicon dioxide foreign particles having a size of 1 μm or more and 10 μm or less present on at least one surface of the paper for a glass plate is preferably 50 pieces / mm 2 the following.

[0022] The air permeation resistance (gas permeability resistance) of the above-mentioned paper for glass plates is preferably 5 seconds or more.

[0023] The present invention relates to a glass plate laminate obtained by laminating at least two glass plates, wherein the glass plate laminate comprises the paper for glass plates of the present invention between adjacent glass plates.

[0024] The present invention relates to a glass plate package including the glass plate stack and a pallet on which the glass plate stack is placed.

[0025] Effects of the Invention

[0026] The present invention can provide a glass plate paper that can suppress the adhesion of micro-sized silica foreign matter to the surface of a glass plate, thereby suppressing the occurrence of defects such as disconnection during wiring formation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a conceptual diagram showing a method for producing paper for a glass plate.

[0028] Figure 2 This is a conceptual diagram showing a pallet on which a glass plate is placed.

[0029] Figure 3 This is a conceptual diagram showing one embodiment of a glass plate package.

[0030] Description of symbols

[0031] 10...Glass plate package, 12...Glass plate laminate, 14...Glass plate, 16...Paper for glass plate, 18...Tilting table, 22...Base table, 24...Placing table, 42...Paper roll, 100...Glass plate paper manufacturing device, 112...Head box, 114...Wire section, 116...Lower wire, 118...Upper wire, 120...Pressing section, 124...Drying section, 126...Calendering section, 128...Reel, 130...Big roll, 134...Cutter, 136...Reeling machine DETAILED DESCRIPTION

[0032] Hereinafter, preferred embodiments of the paper for glass plates of the present invention will be described. The embodiments described below are examples, and the present invention is not to be construed as being limited to these embodiments.

[0033] From the perspective of transportation efficiency, glass plates are transported by stacking at least two glass plates and placing them on a pallet. An object obtained by stacking at least two glass plates and sandwiching paper between adjacent glass plates is called a glass plate stack, and a package obtained by placing the glass plate stack on a pallet is called a glass plate package. In a glass plate stack, when glass plates contact each other, scratches may occur on the surface of the glass plates. Such scratches are known to cause problems such as broken wires in the manufacturing process of displays, etc. Therefore, by sandwiching glass plates between glass plates with paper, scratches on the surface of the glass plates are suppressed.

[0034] However, since foreign matter contained in the glass plate paper adheres to the surface of the glass plate, problems such as disconnection may occur. In particular, with the recent increase in the definition of displays, problems such as disconnection may occur even when using glass plate paper that did not cause any problems in the past.

[0035] Therefore, the inventors of the present invention analyzed the foreign matter attached to the glass plate. As a result, it was found that a large amount of silicon-containing foreign matter was attached to the surface of the glass plate. In addition, it was found that among the silicon-containing foreign matter, especially micro-sized silicon dioxide foreign matter was difficult to be removed by cleaning before wiring formation, and remained after cleaning, thus becoming a problem. In this specification, micro-sized silicon dioxide foreign matter refers to silicon dioxide foreign matter with a longest diameter of less than 10 μm.

[0036] It is generally believed that silica foreign matter with a longest diameter greater than 10 μm can be easily removed by cleaning before forming wiring on the glass plate, and is therefore less likely to cause problems such as disconnection than silica foreign matter with a longest diameter of 10 μm or less.

[0037] Among silicon-containing foreign matter, especially micro-sized silicon dioxide foreign matter is difficult to be removed by washing and is likely to remain even after washing. This is believed to be because silicon-containing foreign matter other than silicon dioxide foreign matter, such as talc, is mostly spherical, whereas silicon dioxide foreign matter is mostly flat. In other words, this is believed to be because, in the case of a flat shape, the height is low, and therefore, it is difficult to be removed by a washing process such as brush washing and is likely to remain.

[0038] In addition, the inventors found that the silica foreign matter remaining on the surface of the glass plate is attached to the surface of the glass plate from the paper. From the above, it is important to reduce the micro-sized silica foreign matter present in the paper for glass plates.

[0039] (Method for manufacturing paper for glass plate)

[0040] A stock solution (a liquid obtained by diluting pulp with water) for paper for glass plates is supplied in a sheet form from a headbox 112 to a lower wire 116 provided on a wire section 114. Next, the stock solution supplied to the lower wire 116 is sandwiched between the lower wire 116 and the upper wire 118, thereby being spread with a uniform thickness and dehydrated, thereby forming wet paper (paper).

[0041] The lower net 116 and the upper net 118 of the net part 114 are permeable membranes formed into an endless belt shape. Specifically, they are nets made of plastic or metal materials or endless belts made of felt containing natural fibers or synthetic fibers.

[0042] The lower net 116 and the upper net 118 are suspended on a plurality of rollers, and are moved around at a predetermined speed by transmitting a driving force of a motor (not shown) to a driving roller among the plurality of rollers.

[0043] The wet paper formed in the wire section 114 is conveyed to the press section 120 including a press roll, an endless belt-shaped felt, a press roll pair, and the like, where it is further dehydrated and pressed.

[0044] The wet paper having passed through the press section 120 is conveyed to a drying section 124 composed of a plurality of rolls, and is dried in an atmosphere of, for example, about 120° C. while passing through the drying section 124 .

[0045] When passing through the drying section 124 , if the wet paper is directly conveyed at a high speed, there is a possibility that the paper may break, so the wet paper is conveyed in a state where an auxiliary member called a canvas is in contact with the wet paper.

[0046] The paper dried in the drying section 124 is transported to the calendering section 126, where it can be calendered by clamping and conveying with calendering rollers, so that the front and back surfaces are smoothed. It should be noted that, as needed, a coating section can be provided between the drying section 124 and the calendering section 126 to apply a coating or the like on the surface of the smoothed paper.

[0047] The paper subjected to the calendering treatment in the calendering section 126 is wound around a reel 128 as a paper clip for a glass plate, and is formed into a roll (hereinafter referred to as a jumbo roll 130).

[0048] For the glass plate paper made into a large roll 130, the glass plate paper is usually cut into a width corresponding to the product and rolled up to make a long glass plate paper roll 42 with a specified length of about 8000m to about 10000m.

[0049] The glass sheet paper is fed out from the large roll 130, cut into a predetermined width (cut in the length direction) by a cutter 134, and wound up by a winder 136. When the glass sheet paper fed out from the large roll 130 reaches a predetermined length, it is cut into a predetermined length (cut in the width direction) by the cutter 134, and becomes a paper roll 42 formed by winding up the long glass sheet paper of the predetermined width.

[0050] The long glass plate paper wound on the paper roll 42 is cut into slices (rectangular shapes) having a size corresponding to the stacked glass plates, and is sandwiched between the stacked glass plates.

[0051] (Silicon concentration)

[0052] Silicon contained in the interlayer for glass plates mainly comes from cellulose pulp or water as raw materials, and dust in the air mixed in during the manufacturing process. Silicon exists in the manufactured interlayer for glass plates mainly in the form of silicon-containing foreign matter such as hydrous magnesium silicate (hereinafter also referred to as "talc") and silicon dioxide.

[0053] By adjusting the silicon concentration of the glass plate paper of the present invention to 200 ppm or less as measured by fluorescent X-ray analysis, the silicon dioxide foreign matter in the glass plate paper can be sufficiently reduced, and the occurrence of problems such as wire breakage can be reduced.

[0054] The silicon concentration is preferably 150 ppm or less, more preferably 130 ppm or less, further preferably 100 ppm or less, and particularly preferably 50 ppm or less.

[0055] In addition, in this specification, the silicon concentration when the paper for glass plates is measured by fluorescent X-ray analysis is also referred to as X. X is measured by the following method.

[0056] (Method for measuring silicon concentration X)

[0057] The fluorescent X-ray analysis in the present invention can be implemented, for example, using a commercially available fluorescent X-ray analysis device such as ZXS PRIMUS (Rigaku Co., Ltd.). As a pretreatment for the fluorescent X-ray analysis, the glass plate paper is pre-cut into a size suitable for measurement using a cutter or the like. The cut paper is placed on a sample table. At this time, in order to avoid noise in the measurement caused by the components of the sample table, a sample table with a high purity of a known composition can be used, a cup-shaped sample table with a deep bottom can be used, or the glass plate paper can be overlapped. Next, the glass plate paper is fixed using a lid with a hole in the measurement area. The sample table is placed in a fluorescent X-ray analysis device, the inside of the device is made into a vacuum, and then X-rays are irradiated on the measurement surface to measure and analyze the fluorescent X-rays generated from the glass plate paper.

[0058] Since the larger the evaluation area, the more stable the result, the evaluation area is preferably 10 square millimeters or more, more preferably 100 square millimeters or more, and further preferably 600 square millimeters or more. In this specification, unless otherwise specified, the evaluation area is 700 square millimeters.

[0059] In order to quantify the detected elements, a standard sample with a known concentration was measured, and then the value of each element was calibrated according to its X-ray intensity. The power during the measurement was set to 3000W.

[0060] During the determination, the contents of each element, including sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, potassium, calcium, iron, nickel, copper and zirconium, were quantified.

[0061] When the silicon concentration is too low, the foam breaking property is poor when the raw material liquid of the glass plate paper is stirred, and holes may be formed in the glass plate paper. Therefore, the silicon concentration is preferably 10 ppm or more, more preferably 15 ppm or more, and further preferably 20 ppm or more.

[0062] The silicon concentration is affected by cellulose pulp as a raw material, water as a raw material, and the production process of paper.

[0063] Regarding the cellulose pulp as a raw material, the silicon concentration can be reduced by selecting a pulp that does not contain silicone oil or uses a small amount of silicone oil, selecting a pulp that does not contain talc as a pitch control agent, and selecting a pulp from which fine minerals and dust have been removed by applying a strong centrifugal force. Regarding the water as a raw material, the silicon concentration can be reduced by using water from which the silicon component of minerals from groundwater or river water has been removed by sufficient filtration. In addition, in the method for manufacturing paperboard, the silicon concentration can be reduced by performing the papermaking process in a clean room to prevent the intrusion of dust, or by separating the papermaking process using cellulose pulp containing silicone oil from the papermaking process for glass plate paperboard.

[0064] As the cellulose pulp, chemical pulps such as kraft pulp (KP), sulfite pulp (SP), and soda pulp (AP); semi-chemical pulps such as semi-chemical pulp (SCP) and chemical groundwood pulp (CGP); mechanical pulps such as groundwood pulp (GP), thermomechanical pulp (TMP, BCTMP), and refined groundwood pulp (RGP); non-wood fiber pulps made from paper mulberry, ramie, hemp, and kenaf; and glass paper made from various raw materials such as synthetic pulp can be used. In addition, pulps obtained by mixing these materials may be used.

[0065] (Calcium concentration)

[0066] Calcium contained in the paper for glass plates mainly comes from cellulose pulp or water as raw materials, and dust in the air mixed in during the manufacturing process. Calcium exists in the manufactured paper for glass plates in the form of silicon-containing foreign matter such as calcium metasilicate and calcium orthosilicate, or calcium carbonate.

[0067] In this specification, the calcium concentration when the paper for glass plates is measured by fluorescent X-ray analysis is also referred to as Y. Y is measured by the same operation procedure as in the above (method for measuring silicon concentration X).

[0068] The smaller the value obtained by dividing the silicon concentration by the calcium concentration, that is, the X / Y ratio, the more calcium exists relative to silicon. Calcium exists in the form of silicon-containing compounds such as calcium metasilicate and calcium orthosilicate in addition to calcium carbonate. Therefore, it is believed that the greater the calcium concentration Y, the smaller the proportion of silicon existing in the form of silicon dioxide, and the less silicon dioxide foreign matter.

[0069] The glass plate paper of the present invention can sufficiently reduce silica foreign matter in the glass plate paper by making the X / Y ratio below 4.00. The X / Y ratio is preferably below 3.50, more preferably below 3.00, further preferably below 2.00, particularly preferably below 1.00, and most preferably below 0.50.

[0070] In addition, it is believed that when Y is too large, the silica foreign matter decreases, but the calcium-containing foreign matter such as calcium carbonate increases, which may become a problem. Therefore, Y is preferably 400 ppm or less, more preferably 300 ppm or less, and further preferably 250 ppm or less.

[0071] When Y is too small, the foam breaking property when stirring the raw material liquid of the glass plate paper is poor, and holes may be formed in the glass plate paper. Therefore, Y is preferably 20 ppm or more, more preferably 30 ppm or more, and further preferably 50 ppm or more.

[0072] By using a raw paste having a high calcium content, the X / Y ratio can be reduced.

[0073] (Magnesium concentration)

[0074] The magnesium contained in the glass plate paper mainly comes from the cellulose pulp or water used as the raw material and the dust in the air mixed in during the manufacturing process. Magnesium exists in the manufactured glass plate paper mainly in the form of silicon-containing foreign matter such as talc.

[0075] In this specification, the magnesium concentration when the paper for glass plates is measured by fluorescent X-ray analysis is also referred to as Z. Z is measured by the same operation procedure as in the above (method for measuring silicon concentration X).

[0076] The smaller the X / Z ratio, which is the value obtained by dividing the silicon concentration by the magnesium concentration, the more magnesium exists relative to the silicon. As described above, magnesium exists in the form of silicon-containing compounds such as talc, so it is believed that the larger the Z, the smaller the proportion of silicon existing in the form of silicon dioxide, and the less silicon dioxide foreign matter.

[0077] The X / Z ratio of the paper for a glass plate of the present invention is preferably 3.00 or less, more preferably 2.50 or less, further preferably 2.00 or less, particularly preferably 1.00 or less.

[0078] In addition, it is believed that if Z is large, the silicon dioxide foreign matter is reduced, but the increase of talc may become a problem. Therefore, the content of magnesium is preferably below 100ppm, more preferably below 70ppm. There is no particular restriction on the lower limit of Z, preferably above 10ppm, more preferably above 20ppm.

[0079] (Measurement method of silicon-containing foreign matter and silicon dioxide foreign matter)

[0080] Silicon-containing foreign matter is measured, for example, by a scanning electron microscope and an energy dispersive X-ray analyzer mounted on the scanning electron microscope. As a pretreatment for the measurement, the sample cut into small pieces may be treated with a conductive film of elements not to be measured, such as carbon and platinum. The paper is placed on a scanning electron microscope, and then a reflected electron detector is used to identify elements heavier than carbon, which is the main element constituting the paper, based on the brightness of the image. In the method using the reflected electron detector, elements heavier than carbon are generally represented by bright pixels. Initially, for example, 100 areas of 0.1 mm × 0.1 mm are measured. Next, while measuring the number of silicon-containing foreign matter greater than 1 μm and less than 10 μm, and the number of silicon dioxide foreign matter, foreign matter other than carbon greater than 1 μm is counted. For each foreign matter detected by the reflected electron detector, the size is calculated from the number of pixels, and for particles with a longest diameter of 1 μm or more and 10 μm or less, the elements are analyzed one by one using an energy dispersive X-ray analyzer, and particles containing 10% by weight or more of silicon in elements excluding carbon and oxygen are considered silicon-containing objects. In addition, particles containing 80% by weight or more of silicon are considered silicon dioxide foreign matter.

[0081] When measuring the number of silicon-containing foreign matter and silicon dioxide foreign matter of 0.5 μm or more and 50 μm or less, foreign matter other than carbon of 0.5 μm or more is counted and measured in the same manner.

[0082] When the longest diameter of the silicon-containing foreign matter is less than 1 μm, and thus sufficiently smaller than the wiring width and the spacing width, it is less likely to cause a defect such as a broken wire. In addition, it is known that the smaller the longest diameter of silicon dioxide foreign matter is, the more difficult it is to remove by cleaning. In particular, silicon dioxide foreign matter with a longest diameter of less than 10 μm is likely to remain on the surface of the glass plate even after cleaning.

[0083] The number of silicon-containing foreign particles with a size of 0.5 μm or more and 50 μm or less present on at least one surface of the paper of the present embodiment is preferably 2000 pieces / mm 2 Below, more preferably 1000 pieces / mm 2 Below, more preferably 200 pieces / mm 2 Below, particularly preferably 20 / mm 2 It is considered that the less the silicon-containing foreign matter of 0.5 μm or more and 50 μm or less contained in the paper is, the less the silicon dioxide foreign matter of 1 μm or more and 10 μm or less that becomes a problem is.

[0084] In addition, the number of silicon-containing foreign matter with a size of 1 μm or more and 10 μm or less present on at least one surface of the paper of the present embodiment is preferably 1000 pieces / mm. 2 Below, more preferably 100 pieces / mm 2 Below, more preferably 10 / mm 2 It is considered that the less the silicon-containing foreign matter with a size of 1 μm or more and 10 μm or less contained in the paper, the less the silicon dioxide foreign matter with a size of 1 μm or more and 10 μm or less will be.

[0085] In addition, the number of silicon dioxide foreign particles with a size of 0.5 μm or more and 50 μm or less present on at least one surface of the paper of the present embodiment is preferably 100 pieces / mm. 2 Below, more preferably 50 pieces / mm 2 Below, more preferably 20 pieces / mm 2 Below, particularly preferably 10 / mm 2 It is considered that the less the silica foreign matter of 0.5 μm or more and 50 μm or less contained in the paper, the less the silica foreign matter of 1 μm or more and 10 μm or less will be.

[0086] In addition, the number of silicon dioxide foreign particles with a size of 1 μm or more and 10 μm or less present on at least one surface of the paper of the present embodiment is preferably 50 pieces / mm. 2 Below, more preferably 30 / mm 2 Below, more preferably 10 / mm 2 Below, particularly preferably 5 / mm 2The fewer the silicon dioxide foreign matter of 1 μm or more and 10 μm or less, the less the silicon dioxide foreign matter transferred to the glass plate, and the less likely it is to cause problems such as disconnection.

[0087] (Breathable resistance)

[0088] The air resistance is measured according to the method of JIS P8117. The air resistance is preferably 5 seconds or more, more preferably 10 seconds or more, and particularly preferably 15 seconds or more. When the air resistance is 5 seconds or more, it is easy to remove only one paper clip from the glass plate package using a vacuum adsorption pad. On the other hand, when the air resistance is less than 5 seconds, when it is desired to remove a paper clip from the glass plate package using a vacuum adsorption pad, it is easy to simultaneously remove the glass plate located under the paper clip to be removed. In addition, there is no particular restriction on the upper limit of the air resistance, but it is preferably 50 seconds or less, more preferably 45 seconds or less, and further preferably 40 seconds or less.

[0089] (Characteristics of glass plate clips)

[0090] The basis weight of the paper for glass plates is measured according to the method of JIS P8118. The smaller the basis weight of the paper, the smaller the weight during transportation, which is preferred. However, if the basis weight is too small, sufficient cushioning cannot be obtained. Therefore, the basis weight of the paper is preferably 10 g / m 2 More preferably 20 g / m 2 More preferably, 30 g / m 2 In addition, when the basis weight of the paper is too large, the mass during transportation becomes large, which is not preferred. Therefore, the basis weight of the paper is preferably 100g / m 2 Below, more preferably 90g / m 2 Below, more preferably 80g / m 2 the following.

[0091] From the viewpoint of cushioning properties, the thickness of the paper is preferably 50 μm or more and 200 μm or less. The density of the paper is preferably 0.30 g / cm 3 Above and 1.00g / cm 3 the following.

[0092] (Glass Plate Laminate)

[0093] The glass plate laminate 12 of the present embodiment is obtained by laminating at least two glass plates 14 , and has the paper 16 for glass plates of the present invention between adjacent glass plates.

[0094] (Glass plate packaging)

[0095] The glass plate package 10 of the present embodiment includes a glass plate laminate 12 and a pallet on which the glass plate laminate 12 is placed.

[0096] The pallet is a known glass plate packaging pallet, and comprises a base 22, an inclined platform 18 provided on the upper surface of the base 22, and a mounting platform 24 supporting the end surface of the glass plate stack 12. The angle θ between the mounting platform 24 and the inclined platform 18 is not particularly limited as long as the glass plate 14 can be stably loaded, and is preferably 90°.

[0097] The angle γ of the tilting platform 18 is the angle between the tilting platform 18 and the horizontal plane. Figure 2 As shown, when the upper surface of the base on which the tilting platform 18 and the loading platform 24 are provided is horizontal, the angle γ of the tilting platform 18 is the angle formed by the tilting platform 18 and the base 22. The closer the angle γ of the tilting platform 18 is to 90°, the more space is saved. However, since the end face of the glass plate 14 is subjected to great pressure, defects such as notches may occur. In addition, the closer the tilting platform 18 is to 0°, the more dispersed the pressure applied to the glass plate 14 is, and defects such as notches on the end face can be suppressed. However, since a large space is required, the efficiency of storage and transportation is reduced. In this specification, a pallet with an angle of the tilting platform 18 of less than 10° is referred to as a transversely stacked pallet, and a pallet with an angle of the tilting platform greater than 10° is referred to as a longitudinally stacked pallet.

[0098] The pallet used can be a pallet stacked horizontally or vertically, but in the case of a large glass plate, due to the deadweight of the glass plate 14, a large pressure is applied to the end of the glass plate 14. Therefore, in the case of a large glass plate, it is preferred to use a pallet that carries the glass plate in a horizontally stacked state. In addition, the larger the glass plate 14, the greater the pressure applied to the end face of the glass plate 14, so the angle of the tilting platform is preferably above 0° and below 5°, more preferably above 0° and below 3°, and further preferably above 0° and below 1°. However, when the glass plate 14 is stored in a truck, a container, etc. for transporting the glass plate 14, it is sometimes impossible to store it using a pallet stacked horizontally. Therefore, in order to save space, a pallet stacked vertically can be used.

[0099] A large glass plate refers to, for example, a glass plate with at least one side of 2400 mm or more, and as a specific example, refers to a glass plate with a long side of 2400 mm or more and a short side of 2000 mm or more. The large glass plate is preferably a glass plate with at least one side of 2400 mm or more, for example, a glass plate with a long side of 2400 mm or more and a short side of 2100 mm or more, more preferably a glass plate with at least one side of 3000 mm or more, for example, a glass plate with a long side of 3000 mm or more and a short side of 2800 mm or more, further preferably a glass plate with at least one side of 3200 mm or more, for example, a glass plate with a long side of 3200 mm or more and a short side of 2900 mm or more, and particularly preferably a glass plate with at least one side of 3300 mm or more, for example, a glass plate with a long side of 3300 mm or more and a short side of 2950 mm or more.

[0100] The thickness of the glass plate 14 is preferably 1 mm or less. By making the glass plate 14 thinner, light weight can be achieved. The thickness of the glass plate 14 of the present invention is more preferably 0.75 mm or less, further preferably 0.6 mm or less, particularly preferably 0.5 mm or less, and most preferably 0.4 mm or less. The thickness can be set to 0.1 mm or less or 0.05 mm or less. However, from the viewpoint of preventing self-weight deflection, the thickness is preferably 0.1 mm or more, and more preferably 0.2 mm or more.

[0101] The glass plate 14 is preferably used for a display. Since there are few silicon dioxide foreign matters of 1 μm or more and 10 μm or less on the main surface of the glass plate 14, it is possible to suppress defects such as disconnection. As a display, it is preferably used for a substrate of a liquid crystal display.

[0102] As mentioned above, the glass plate paper 16, the glass plate laminate 12 and the glass plate package 10 are described in detail, but the present invention is not limited to the above-mentioned examples, and it is obvious that various improvements and changes can be made without departing from the scope of the present invention.

[0103] <Example>

[0104] The present invention is described in detail below by way of examples, but the present invention is not limited to these examples. Examples 1 to 4 are examples, and Examples 5 to 7 are comparative examples. In addition, for cases not specifically described, the manufactured paper was processed according to JIS P8111 and then measured.

[0105] The silicon concentration, magnesium concentration, and calcium concentration contained in the paper of Examples 1 to 7 were measured twice each by fluorescent X-ray analysis, and the average values ​​were calculated. Next, the number of silicon-containing foreign particles with the longest diameter of 0.5 μm or more and 50 μm or less and 1 μm or more and 10 μm or less (pieces / mm) was measured by a scanning electron microscope and an energy dispersive X-ray analyzer mounted on the scanning electron microscope. 2 ) and the number of silica foreign particles with the longest diameter of 0.5 μm to 50 μm and 1 μm to 10 μm (pieces / mm 2 ). Use different paper clips to measure the silicon-containing foreign matter and silicon dioxide foreign matter of each size twice, and calculate the average value.

[0106] The glass plates of Examples 1 to 7 were formed into a size of 2330 mm×1990 mm with paper, and were sandwiched between FPD glass plates having a thickness of 0.5 mm and a size of 2250 mm×1950 mm to produce a glass plate laminated body in which a plurality of glass plates were laminated.

[0107] Each glass plate stack is placed on Figure 2 The glass plates were stacked vertically on the pallet shown (600 glass plates) to produce a glass plate package. The produced glass plate package was stored for 10 days.

[0108] The glass plate closest to the tilting table of the pallet was taken out from the glass plate package, the glass plate was cleaned, and then the amount of foreign matter remaining on the surface of the glass plate was measured using an optical inspection machine.

[0109] Each measurement was performed by the following method.

[0110] <Measurement of Element Concentration of Paper for Glass Plates by Fluorescent X-ray Analysis>

[0111] The approximate center of the paper clip was measured using a fluorescent X-ray analyzer (manufacturer: Rigaku Corporation, model: ZXS PRIMUSII). Next, in order to detect the quantitative content of the elements, a standard sample with a known concentration was measured in advance, and the value of each element was calibrated based on its X-ray intensity. The power during the measurement was set to 3000W, and the content of each element of magnesium, aluminum, silicon, and calcium was quantified.

[0112] <Measurement of the number of silicon-containing foreign matter and silicon dioxide foreign matter contained in paper for glass plates>

[0113] The silicon-containing foreign matter contained in the paper was measured at the approximate center of the paper using a scanning electron microscope (manufacturer: JEOL Ltd., model: JSM-6490LA) and an energy dispersive X-ray analyzer (manufacturer: Oxford Instruments, model: X-MAXN50). The acceleration voltage during observation was set to 20 kV.

[0114] When measuring silicon-containing foreign matter and silicon dioxide foreign matter with a maximum diameter of 0.5 μm or more and 50 μm or less, first measure 100 0.1 mm × 0.1 mm areas, and count foreign matter with a maximum diameter of 0.5 μm or more other than carbon. For each foreign matter detected by the reflected electron detector, the size is calculated from the number of pixels, and for particles with a maximum diameter of 0.5 μm or more and 50 μm or less, the elements are analyzed one by one using an energy dispersive X-ray analyzer, and the number of particles containing 10% by weight or more of silicon (silicon-containing foreign matter) and 80% by weight or more of silicon (silicon dioxide foreign matter) in elements excluding carbon and oxygen is counted.

[0115] Furthermore, the same measurement is performed when measuring silicon-containing foreign matter and silicon dioxide foreign matter having a longest diameter of 1 μm or more and 10 μm or less.

[0116] <Measurement and Evaluation of Foreign Matter Remaining on the Surface of Glass Plate>

[0117] The glass plate closest to the tilting table of the pallet was taken out from the glass package stored for 10 days, and the glass plate was cleaned, and then the number of foreign matter remaining on the surface of the glass plate was measured using an optical inspection machine (manufacturer: Hitachi High-Tech Precision Systems Co., Ltd., model: GI). The glass plate was cleaned by conveying the glass plate in a horizontal direction and wiping it with a PVA sponge while spraying pure water.

[0118] The number of foreign matters present on the surface of the glass plate was evaluated as A if the number was less than 50, the number was evaluated as B if the number was 50 or more and less than 60, and the number was evaluated as C if the number was 60 or more.

[0119] (Example 1, Example 2)

[0120] The raw material pulp with high calcium content is diluted with groundwater filtered by a process filter with a filtration accuracy of 200 μm, thereby obtaining a raw material liquid for paper. The raw material liquid is spread at a uniform thickness and dehydrated to obtain wet paper. The obtained wet paper is dehydrated by pressing with a press roll. The pressed wet paper is dried in an atmosphere of about 120° C. to obtain paper.

[0121] (Example 3, Example 4)

[0122] The production was carried out in the same manner as in Example 1 except that a slurry having a high silicon content was used as a raw material.

[0123] (Example 5)

[0124] The production was carried out in the same manner as in Example 1 except that a slurry having a high silicon content and a low calcium content was used as a raw material.

[0125] (Example 6, Example 7)

[0126] The production was carried out in the same manner as in Example 1 except that a slurry having high silicon and magnesium contents and to which talc was added was used as a raw material.

[0127] <Results>

[0128] The measurement results and evaluation results are shown in Table 1. According to Table 1, when the silicon concentration is 200 ppm or less and the X / Y ratio obtained by dividing the silicon concentration by the calcium concentration is 4.00 or less, the contamination is A or B. On the other hand, when the silicon concentration is greater than 200 ppm and the X / Y ratio is greater than 4.00, the contamination is C in all cases.

[0129] From this result, it can be understood that the silicon concentration and the X / Y ratio are related to the number of silicon dioxide particles present in the paper and the contamination of the glass plate.

[0130]

Claims

1. A glass plate paper, wherein the glass plate paper has cellulose pulp as a main component and the basis weight of the glass plate paper is 10 g / m 2 Above and 100g / m 2 the following, It is characterized in that When the silicon concentration, calcium concentration, and magnesium concentration of the paper for glass plates measured by fluorescent X-ray analysis are denoted as X, Y, and Z, respectively, X is 10 ppm or more and 200 ppm or less, Y is 20 ppm or more and 400 ppm or less, Z is 20 ppm or more and 100 ppm or less, and The X / Y ratio, which is a value obtained by dividing the silicon concentration by the calcium concentration, is 4.00 or less.

2. The paper for glass plates according to claim 1, wherein: The X / Z ratio, which is a value obtained by dividing the silicon concentration by the magnesium concentration, is 3.00 or less.

3. The paper for glass plates according to claim 1 or 2, wherein: The number of silicon-containing foreign matter with a size of 0.5 μm or more and 50 μm or less present on at least one surface of the paper for a glass plate is 2000 pieces / mm 2 the following.

4. The paper for glass plates according to claim 1 or 2, wherein: The number of silicon-containing foreign matter having a size of 1 μm or more and 10 μm or less existing on at least one surface of the paper for a glass plate is 1000 pieces / mm 2 the following.

5. The paper for glass plates according to claim 1 or 2, wherein: The number of silicon dioxide foreign matter with a size of 0.5 μm or more and 50 μm or less present on at least one surface of the paper for a glass plate is 100 pieces / mm 2 the following.

6. The paper for glass plates according to claim 1 or 2, wherein: The number of silicon dioxide foreign particles having a size of 1 μm or more and 10 μm or less present on at least one surface of the paper for a glass plate is 50 pieces / mm 2 the following.

7. The paper for glass plates according to claim 1 or 2, wherein: The air permeability resistance of the paper for glass plates is 5 seconds or more.

8. A glass plate laminate, the glass plate laminate being obtained by laminating at least two or more glass plates, wherein: The said glass plate laminated body has the paper for glass plates as described in any one of Claims 1 to 7 between adjacent glass plates.

9. A glass plate package, wherein: The glass plate package comprises the glass plate laminated body according to claim 8 and a pallet on which the glass plate laminated body is placed.

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