Glass plate interleaving paper

Abstract

To provide laminated paper for a glass plate that suppress silica foreign matter of, especially, minute size which is silicon-containing foreign matter from sticking on a surface of a glass plate.SOLUTION: There is provided laminated paper for a glass plate that consists principally of cellulose pulp, wherein X is equal to 200 ppm or less and a ratio X / Y obtained by dividing silicon density by calcium density is equal to 4.00 or less when the silicon density measured by fluorescent X-ray analysis is represented as X and the calcium density is represented as Y.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] In glass plates used in flat panel displays (FPDs) such as liquid crystal displays, fine electronic wiring (hereinafter also referred to as "wiring") is formed on the glass plate surface, so even slight scratches or dirt on the surface can cause defects such as disconnection. Therefore, the glass plate surface must be highly clean.

[0003] In order to improve the efficiency of transportation, glass plates are transported in a stacked state. At this time, glass plate interleaving paper (hereinafter simply referred to as "interleaving paper") is placed between adjacent glass plates to prevent scratches on the surfaces of the glass plates during transportation.

[0004] However, foreign matter may be mixed in during the process of manufacturing the interleaf paper, or may adhere to the surface of the glass plate from the interleaf paper due to the influence of various chemical substances. Most of the foreign matter adhering to the surface of the glass plate is removed by cleaning before the process of forming wiring on the surface of the glass plate, but it may remain on the surface of the glass plate even after cleaning and may cause disconnection, etc. Therefore, there is a demand for an interleaf paper for glass plates that reduces the amount of foreign matter adhering to the surface of the glass plate.

[0005] Patent Document 1 attempts to reduce contamination of the surface of glass plates by lowering the concentrations of aluminum, silicon, magnesium, and the like contained in glass plate interleaf paper. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2017-210286 Summary of the Invention [Problem to be solved by the invention]

[0007] However, as displays have become increasingly high-definition in recent years, the width and pitch of the wiring formed on the surface of the glass plate have become thinner than before, and this has led to problems such as wire breakage during wiring formation, even when using glass plate interleaving paper such as that described in Patent Document 1.

[0008] The inventors investigated the above problem and found that the cause was minute silica particles that remained on the surface of the glass plate even after cleaning. Since minute silica particles are difficult to remove in the cleaning process before forming wiring, it is important to prevent minute silica particles from adhering to the surface of the glass plate.

[0009] An object of the present invention is to provide an interleaving paper for glass plates that suppresses the adhesion of minute silica foreign matter to the surface of a glass plate, thereby suppressing the occurrence of defects such as disconnection during wiring formation. [Means for solving the problem]

[0010] The glass plate interleaving paper according to the present invention is mainly composed of cellulose pulp and has a basis weight of 10 g / m 2 More than 100g / m 2 The glass plate interleaving paper is characterized in that, when a silicon concentration measured by fluorescent X-ray analysis is X and a calcium concentration is Y, X is 200 ppm or less, and an X / Y ratio, which is a value obtained by dividing the silicon concentration by the calcium concentration, is 4.00 or less.

[0011] The glass plate interleaving paper preferably has an X / Z ratio, which is the value obtained by dividing the silicon concentration by the magnesium concentration, where Z is the magnesium concentration measured by fluorescent X-ray analysis, of 3.00 or less.

[0012] The Z is preferably 20 ppm or more and 100 ppm or less.

[0013] The Y is preferably 20 ppm or more and 400 ppm or less.

[0014] The glass plate interleaving paper has a surface on at least one side of which the number of silicon-containing foreign particles having a size of 0.5 μm or more and 50 μm or less is 2000 pieces / mm 2 It is preferable that:

[0015] The glass plate interleaving paper has a surface on at least one side of which the number of silicon-containing foreign particles having a size of 1 μm or more and 10 μm or less is 1000 pieces / mm 2 It is preferable that:

[0016] The glass plate interleaving paper has a surface area of ​​at least one of the interleaving paper surfaces that is less than 100 silica particles / mm 2 It is preferable that:

[0017] The glass plate interleaving paper has a surface on at least one side of which the number of silica foreign particles having a size of 1 μm or more and 10 μm or less is 50 pieces / mm 2 It is preferable that:

[0018] The glass plate interleaving paper preferably has an air resistance of 5 seconds or more.

[0019] The glass plate laminate according to the present invention comprises at least two glass plates laminated together, and has the glass plate interleaving paper according to the present invention between adjacent glass plates.

[0020] The glass sheet package according to the present invention comprises the glass sheet laminate and a pallet on which the glass sheet laminate is placed. Effect of the Invention

[0021] It is possible to provide an interleaving paper for glass sheets that prevents minute silica foreign matter from adhering to the surface of the glass sheet, thereby preventing defects such as disconnection during wiring formation. [Brief description of the drawings]

[0022] [Figure 1] FIG. 2 is a conceptual diagram showing a method for producing glass plate interleaf paper. [Diagram 2]FIG. 2 is a conceptual diagram showing a pallet on which a glass plate is placed. [Diagram 3] FIG. 1 is a conceptual diagram showing one embodiment of a glass plate package. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, preferred embodiments of the glass plate interleaving paper according to the present invention will be described. The embodiments described below are merely examples, and the present invention should not be construed as being limited to these embodiments.

[0024] From the viewpoint of transport efficiency, glass plates are transported by stacking at least two or more glass plates and placing them on a pallet. A glass plate laminate is a product of stacking at least two or more glass plates and interposing interleaf paper between adjacent glass plates, and a glass plate laminate placed on a pallet is a glass plate package. In the glass plate laminate, when glass plates come into contact with each other, scratches may occur on the surfaces of the glass plates. It is known that such scratches cause problems such as disconnection in the manufacturing process of displays and the like. Therefore, by interposing interleaf paper for glass plates between the glass plates, the occurrence of scratches on the surfaces of the glass plates is suppressed.

[0025] However, foreign matter contained in the glass plate interleaving paper may adhere to the surface of the glass plate, causing problems such as disconnection. In particular, with the recent trend toward higher resolution displays, problems such as disconnection have begun to occur even when using glass plate interleaving paper, which did not previously pose a problem.

[0026] Therefore, the present inventors analyzed the foreign matter adhering to the glass plate. As a result, it was found that a large amount of silicon-containing foreign matter was adhering to the surface of the glass plate. In addition, it was found that among the silicon-containing foreign matter, minute-sized silica foreign matter is particularly difficult to remove by cleaning before wiring formation, and remains after cleaning, causing problems. In this specification, minute-sized silica foreign matter refers to silica foreign matter with a maximum diameter of 10 μm or less.

[0027] In addition, silica foreign particles with a maximum diameter of more than 10 μm are easy to remove by cleaning performed before forming wiring on the glass plate, and are therefore less likely to cause defects such as broken wiring than silica foreign particles with a maximum diameter of 10 μm or less.

[0028] Among silicon-containing foreign matters, silica foreign matters of particularly minute size are difficult to remove by washing and tend to remain even after washing. This is thought to be because silicon-containing foreign matters other than silica foreign matters such as talc are often spherical, whereas silica foreign matters tend to be flat in shape. In other words, when they are flat, they are low in height and therefore difficult to remove in a washing process such as brush washing, and therefore tend to remain.

[0029] The inventors also found that the silica foreign matter remaining on the surface of the glass plate is adhered to the surface of the glass plate from the interleaf paper. For these reasons, it is important to reduce the amount of minute silica foreign matter present in the interleaf paper for glass plates.

[0030] (Method of manufacturing interleaving paper for glass plates) The liquid raw material for glass sheet interleaf paper (a liquid obtained by diluting pulp with water) is supplied in the form of a sheet from a head box 112 onto a lower wire 116 installed in a wire part 114. The liquid raw material supplied to the lower wire 116 is then sandwiched between the lower wire 116 and the upper wire 118, whereby it is spread to a uniform thickness and dehydrated to become a wet paper (paper).

[0031] The lower wire 116 and the upper wire 118 of the wire part 114 are permeable membranes formed in an endless belt shape. Specifically, they are endless belts made of a net made of a plastic or metal material, or felt made of natural or synthetic fibers.

[0032] The lower wire 116 and the upper wire 118 are hung around a plurality of rollers, and are rotated at a predetermined speed by transmitting the driving force of a motor (not shown) to a drive roller among the plurality of rollers.

[0033] The wet paper formed in the wire part 114 is transported to a press part 120 having a press roller, an endless belt-like felt, a press roller pair, etc., where further dewatering and pressing are performed.

[0034] The wet paper that has passed through the press part 120 is transported to a dryer part 124 that is composed of a plurality of rollers, and is dried, for example, in an atmosphere of about 120° C. while passing through the dryer part 124 .

[0035] When passing through the dryer part 124, there is a risk of the wet paper breaking if it is transported at high speed as is, so the wet paper is transported while being in contact with an auxiliary member called a canvas.

[0036] The paper dried in the dryer part 124 may be transported to the calendar part 126, where it may be subjected to a calendaring process such as by being sandwiched and transported by calendar rolls, so that the front and back surfaces may be smoothed. If necessary, a coater part may be provided between the dryer part 124 and the calendar part 126, and paint or the like may be applied to the smoothed surface of the paper.

[0037] The paper that has been calendered in the calender part 126 is wound around a reel 128 as interleaf paper for glass plates, and made into a roll (hereinafter, referred to as a jumbo roll 130).

[0038] The glass plate interleaf paper made into the jumbo roll 130 is usually cut to a width according to the product, taken up, and made into the interleaf paper roll 42 in which a long glass plate interleaf paper of a predetermined length, about 8,000 to 10,000 m, is wound.

[0039] The glass plate interleaf paper is sent out from the jumbo roll 130, cut to a predetermined width (cut in the longitudinal direction) by the cutter 134, and taken up by the winder 136. When the glass plate interleaf paper sent out from the jumbo roll 130 reaches a predetermined length, it is cut to the predetermined length (cut in the width direction) by the cutter 134, and the interleaf paper roll 42 is made by winding up a long glass plate interleaf paper of the predetermined width.

[0040] The long glass plate interleaf paper wound around the interleaf paper roll 42 is cut into cut sheets (rectangular shapes) of a size corresponding to the glass plates to be laminated, and is interposed between the glass plates to be laminated.

[0041] (Silicon concentration) The silicon contained in glass plate interleaving paper comes mainly from the raw materials cellulose pulp and water, and from dust in the air that gets mixed in during the manufacturing process. Silicon is present in the manufactured glass plate interleaving paper mainly as silicon-containing foreign matter such as hydrated magnesium silicate (hereinafter also referred to as "talc") and silica.

[0042] The glass plate interleaving paper of the present invention has a silicon concentration of 200 ppm or less as measured by fluorescent X-ray analysis, thereby sufficiently reducing the amount of silica foreign matter in the glass plate interleaving paper and suppressing the occurrence of defects such as breakage.

[0043] 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.

[0044] In this specification, the silicon concentration of the glass plate interleaf paper measured by fluorescent X-ray analysis is also referred to as X. X is measured by the following method.

[0045] (Method of measuring silicon concentration X) The fluorescent X-ray analysis in the present invention can be carried out using a commercially available fluorescent X-ray analyzer such as ZXS PRIMUS (Rigaku Corporation). As a pretreatment for the fluorescent X-ray analysis, the glass plate interleaf paper is cut in advance to a size suitable for measurement using a blade or the like. The cut paper is placed on a sample stage. In this case, a sample stage with a known composition and high purity may be used so that the components of the sample stage do not become noise in the measurement, or a deep cup-shaped sample stage may be used, or the glass plate interleaf paper may be stacked. Next, the glass plate interleaf paper is fixed in place in the measurement area using a lid with holes. The sample stage is placed in an X-ray fluorescent analyzer, and after the inside of the apparatus is evacuated, X-rays are irradiated onto the measurement surface, and the fluorescent X-rays generated from the glass plate interleaf paper are measured and analyzed.

[0046] Since the wider the evaluation area, the more stable the results, the evaluation area is preferably 10 square millimeters or more, more preferably 100 square millimeters or more, and even more preferably 600 square millimeters or more. In this specification, unless otherwise specified, the evaluation area is 700 square millimeters.

[0047] To quantify the detected elements, a standard sample with a known concentration was measured in advance, and the value of each element was corrected from the X-ray intensity. The power for the measurement was 3000W.

[0048] The measurements were carried out to quantify the contents of the following elements: sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, potassium, calcium, iron, nickel, copper, and zircon.

[0049] If the silicon concentration is too low, the foam breaking property is poor when the glass plate interleaf paper raw material liquid is stirred, and holes may be formed in the glass plate interleaf paper. Therefore, the silicon concentration is preferably 10 ppm or more, more preferably 15 ppm or more, and even more preferably 20 ppm or more.

[0050] The silicon concentration is affected by the raw material cellulose pulp, the raw material water, and the manufacturing method of the interleaf paper.

[0051] The silicon concentration can be reduced by selecting raw cellulose pulp that does not contain silicone oil or that contains only a small amount of silicone oil, that does not contain talc as a pitch control agent, or that has been subjected to strong centrifugal force to remove minute ores and dust. The silicon concentration can also be reduced by using water as raw material from which silicon components derived from ores in groundwater or river water have been removed by sufficient filtration. In addition, in the method of manufacturing interleaf paper, 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 interleaf paper.

[0052] The cellulose pulp may be any of various glass plate interleaving papers made from various raw materials, including chemical pulps such as kraft pulp (KP), sulfite pulp (SP), and soda pulp (AP), semi-chemical pulps such as semi-chemical pulp (SCP) and chemi-ground wood pulp (CGP), mechanical pulps such as groundwood pulp (GP), thermomechanical pulp (TMP, BCTMP), and refiner ground wood pulp (RGP), non-wood fiber pulps made from paper mulberry, mitsumata, hemp, kenaf, and the like, and synthetic pulps. Mixtures of these may also be used.

[0053] (Calcium concentration) The calcium contained in the glass sheet interleaving paper is mainly derived from the raw materials cellulose pulp and water, and from dust in the air that gets mixed in during the manufacturing process. Calcium is present in the manufactured glass sheet interleaving paper as silicon-containing foreign matter such as calcium metasilicate and calcium orthosilicate, or as calcium carbonate.

[0054] In this specification, the calcium concentration of the glass plate interleaf paper measured by fluorescent X-ray analysis is also referred to as Y. Y is measured by the same procedure as the above (Method of measuring silicon concentration X).

[0055] The smaller the X / Y ratio, which is the silicon concentration divided by the calcium concentration, the more calcium there is relative to silicon. Since calcium exists not only as calcium carbonate but also as compounds containing silicon, such as calcium metasilicate and calcium orthosilicate, it is thought that the higher the calcium concentration Y, the smaller the proportion of silicon present as silica, and the less silica impurities there will be.

[0056] The glass plate interleaving paper of the present invention is capable of sufficiently reducing silica foreign matter in the glass plate interleaving paper by making the X / Y ratio 4.00 or less. The X / Y ratio is preferably 3.50 or less, more preferably 3.00 or less, even more preferably 2.00 or less, particularly preferably 1.00 or less, and most preferably 0.50 or less.

[0057] On the other hand, if Y is too large, it is thought that the amount of silica foreign matter will be reduced, but the amount of calcium-containing foreign matter such as calcium carbonate will increase, which may cause problems. Therefore, Y is preferably 400 ppm or less, more preferably 300 ppm or less, and even more preferably 250 ppm or less.

[0058] On the other hand, if Y is too small, the bubble breaking property when the raw material liquid of the glass plate interleaf paper is stirred is poor, and holes may be formed in the glass plate interleaf paper. Therefore, Y is preferably 20 ppm or more, more preferably 30 ppm or more, and even more preferably 50 ppm or more.

[0059] By using virgin pulp with a high calcium content, the X / Y ratio can be reduced.

[0060] (Magnesium concentration) The magnesium contained in glass interleaf paper is mainly derived from the raw materials cellulose pulp and water, and from dust in the air that gets mixed in during the manufacturing process. Magnesium is present in the manufactured glass interleaf paper mainly as silicon-containing foreign matter such as talc.

[0061] In this specification, the magnesium concentration measured by fluorescent X-ray analysis of the glass plate interleaf paper is also referred to as Z. Z is measured by the same procedure as in the above (Method of measuring silicon concentration X).

[0062] The smaller the X / Z ratio, which is the silicon concentration divided by the magnesium concentration, the more magnesium there is relative to silicon. As mentioned above, magnesium exists as a compound containing silicon, such as talc, so the larger Z is, the smaller the proportion of silicon present as silica, and the less silica impurities there are.

[0063] The X / Z ratio of the glass plate interleaving paper of the present invention is preferably 3.00 or less, more preferably 2.50 or less, even more preferably 2.00 or less, and particularly preferably 1.00 or less.

[0064] Also, if Z is large, it is considered that the amount of silica foreign matter is reduced, but the amount of talc is increased, which may cause problems. Therefore, the magnesium content is preferably 100 ppm or less, more preferably 70 ppm or less. The lower limit of Z is not particularly limited, but is preferably 10 ppm or more, more preferably 20 ppm or more.

[0065] (Method for measuring silicon-containing foreign matter and silica foreign matter) Silicon-containing foreign matter is measured, for example, by a scanning electron microscope and an energy dispersive X-ray analyzer attached to the scanning electron microscope. As a pretreatment for the measurement, a conductive film treatment of an element not to be measured, such as carbon or platinum, may be performed on a small cut sample. After the slip sheet is set in the scanning electron microscope, a backscattered electron detector is used to distinguish elements heavier than carbon, which is the main element constituting the slip sheet, from the brightness of the image. In the method using this backscattered electron detector, elements heavier than carbon are generally represented by bright pixels. First, for example, 100 areas of 0.1 mm x 0.1 mm are measured. Next, when measuring the number of silicon-containing foreign matter and silica foreign matter of 1 μm or more and 10 μm or less, foreign matter other than carbon that is 1 μm or more in size is counted. The size of each foreign matter detected by this backscattered electron detector is calculated from the number of pixels, and the elements of each particle with a maximum diameter of 1 μm or more and 10 μm or less are analyzed by an energy dispersive X-ray analyzer, and particles containing 10% or more by weight of silicon among elements other than carbon and oxygen are defined as silicon-containing particles. Moreover, particles containing 80% or more by weight of silicon were considered to be silica foreign matter.

[0066] When measuring the number of silicon-containing foreign matter having a size of 0.5 μm or more and 50 μm or less, and silica foreign matter, foreign matter other than carbon having a size of 0.5 μm or more was counted and measured in the same manner.

[0067] When the longest diameter of silicon-containing foreign matter is less than 1 μm, which is sufficiently smaller than the wiring width or pitch width, it is unlikely to cause defects such as disconnection. In addition, it was found that the smaller the longest diameter of silica foreign matter, the more difficult it is to remove by cleaning, and that silica foreign matter with a longest diameter of 10 μm or less in particular is likely to remain on the surface of the glass plate even after cleaning.

[0068] In the slip sheet of the present embodiment, the number of silicon-containing foreign matters having a size of 0.5 μm or more and 50 μm or less present on at least one surface of the slip sheet is 2000 pieces / mm 2 It is preferable that the number of particles is 1000 or less per mm. 2 More preferably, it is 200 pieces / mm or less. 2 More preferably, the number is 20 / mm or less. 2It is believed that the fewer silicon-containing foreign matter of 0.5 μm or more and 50 μm or less contained in the slip paper, the fewer problematic silica foreign matter of 1 μm or more and 10 μm or less will be.

[0069] In addition, the slip sheet of the present embodiment has a silicon-containing foreign matter having a size of 1 μm or more and 10 μm or less present on at least one surface of the slip sheet of 1000 pieces / mm 2 It is preferable that the number of particles is less than 100 / mm 2 More preferably, it is 10 pieces / mm or less. 2 It is believed that the fewer silicon-containing foreign matter of 1 μm or more and 10 μm or less contained in the slip paper, the fewer silica foreign matter of 1 μm or more and 10 μm or less will also be.

[0070] In addition, the slip sheet of the present embodiment has a silica foreign matter having a size of 0.5 μm or more and 50 μm or less present on at least one surface of the slip sheet of 100 pieces / mm 2 Less than 50 pieces / mm is preferable. 2 Less than 20 pieces / mm is more preferable. 2 Less than 10 pieces / mm is more preferable. 2 The following is particularly preferred: It is believed that the fewer the silica foreign matter of 0.5 μm or more and 50 μm or less contained in the slip paper, the fewer the silica foreign matter of 1 μm or more and 10 μm or less.

[0071] In addition, the slip sheet of the present embodiment has a silica foreign matter having a size of 1 μm or more and 10 μm or less present on at least one surface of the slip sheet of 50 pieces / mm 2 Preferably less than 30 pieces / mm 2 Less than 10 pieces / mm is more preferable. 2 Less than 5 pieces / mm is more preferable. 2 The following is particularly preferable: The fewer the silica foreign particles having a size of 1 μm or more and 10 μm or less, the less the silica foreign particles are transferred to the glass plate, and problems such as disconnection are less likely to occur.

[0072] (Air resistance) The air permeability resistance is measured by a method conforming to JIS P8117. The air permeability resistance is preferably 5 seconds or more, more preferably 10 seconds or more, and particularly preferably 15 seconds or more. When the air permeability resistance is 5 seconds or more, it is easy to remove only one interleaf sheet from the glass plate package with a vacuum suction pad. On the other hand, when the air permeability resistance is less than 5 seconds, when an attempt is made to remove the interleaf sheet from the glass plate package with a vacuum suction pad, an abnormality is likely to occur in which the glass plate under the interleaf sheet to be removed is simultaneously removed. In addition, the upper limit of the air permeability resistance is not particularly limited, but is preferably 50 seconds or less, more preferably 45 seconds or less, and even more preferably 40 seconds or less.

[0073] (Characteristics of glass plate interleaving paper) The basis weight of the glass plate interleaf paper is measured according to a method conforming to JIS P8118. A smaller basis weight of the interleaf paper is preferable because it reduces the weight during transportation, but if it is too small, sufficient cushioning properties cannot be obtained. Therefore, the basis weight of the interleaf paper is set at 10 g / m 2 More than 20 g / m is preferable. 2 More preferably, 30 g / m 2 More preferably, the basis weight of the slip sheet is too large, since the weight of the slip sheet increases during transportation. Therefore, the basis weight of the slip sheet is set to 100 g / m 2 Less than 90 g / m is preferable. 2 Less than 80 g / m is more preferable. 2 The following is even more preferred:

[0074] From the viewpoint of cushioning, the thickness of the slip sheet is preferably 50 μm or more and 200 μm or less. The density of the slip sheet is 0.30 g / cm 3 More than 1.00g / cm 3 The following is preferred:

[0075] (Glass plate laminate) The glass plate laminate 12 of this embodiment has at least two glass plates 14 laminated together, with the glass plate interleaving paper 16 according to the present invention between adjacent glass plates.

[0076] (Glass plate packaging) The glass sheet package 10 of this embodiment includes a glass sheet laminate 12 and a pallet on which the glass sheet laminate 12 is placed.

[0077] The pallet is a known pallet for packing glass plates, and includes a base 22, an inclined platform 18 installed on the upper surface of the base 22, and a mounting platform 24 that supports the end faces of the glass plate laminate 12. The angle θ between the mounting platform 24 and the inclined platform 18 is not particularly limited as long as the glass plates 14 can be stably loaded, but it is preferably 90°.

[0078] The angle γ of the inclined platform 18 is the angle between the inclined platform 18 and a horizontal plane. That is, when the top surface of the base on which the inclined platform 18 and the mounting platform 24 are installed is horizontal as shown in FIG. 1, the angle γ of the inclined platform 18 refers to the angle between the inclined platform 18 and the base 22. The closer the angle γ of the inclined platform 18 is to 90°, the more space is saved, but since a large pressure is applied to the edge surface of the glass sheet 14, defects such as chipping may occur. In addition, the closer the angle γ of the inclined platform 18 is to 0°, the more the pressure applied to the glass sheet 14 is dispersed, and defects such as chipping of the edge surface can be suppressed, but since a large space is required, the efficiency of storage and transportation decreases. In this specification, a pallet with an angle of the inclined platform 18 of 10° or less is called a flat-stacked pallet, and a pallet with an angle of more than 10° is called a vertical-stacked pallet.

[0079] The pallet used may be a flat-stacked pallet or a vertical-stacked pallet, but in the case of a large glass plate, a large pressure is applied to the end of the glass plate 14 due to the weight of the glass plate 14. Therefore, in the case of a large glass plate, it is preferable to use a pallet on which the glass plate is placed in a flat-stacked state. In addition, since the pressure applied to the end face of the glass plate 14 increases as the glass plate 14 becomes larger, the angle of the inclined table is preferably 0° or more and 5° or less, more preferably 0° or more and 3° or less, and even more preferably 0° or more and 1° or less. However, when storing the glass plate 14 in a truck or container for transporting the glass plate 14, there are cases where the flat-stacked pallet cannot be used. Therefore, a vertical-stacked pallet may be used to save space.

[0080] The large glass plate is, for example, a glass plate with at least one side of 2400 mm or more, specifically, 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, more 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.

[0081] The thickness of the glass plate 14 is preferably 1 mm or less. By making the glass plate 14 thinner, weight reduction 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 also be 0.1 mm or less, or 0.05 mm or less. However, from the viewpoint of preventing deflection due to its own weight, the thickness is preferably 0.1 mm or more, and more preferably 0.2 mm or more.

[0082] The glass plate 14 is preferably used for a display. Since there is little silica foreign matter of 1 μm or more and 10 μm or less present on the main surface of the glass plate 14, defects such as disconnection can be suppressed. As a display, the glass plate 14 is preferably used as a substrate for a liquid crystal display.

[0083] The glass plate interleaving paper 16, the glass plate laminate 12, and the glass plate package 10 have been described in detail above. However, the present invention is not limited to the above-mentioned examples, and various improvements and modifications may be made without departing from the gist of the present invention.

[0084] <Example> The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. In the following, Examples 1 to 4 are examples, and Examples 5 to 7 are comparative examples. In addition, unless otherwise specified, the manufactured slip sheets were measured after being treated in accordance with JIS P8111.

[0085] The silicon concentration, magnesium concentration, and calcium concentration in the interleaving papers of Examples 1 to 7 were each measured twice using fluorescent X-ray analysis, and the average values ​​were calculated. Next, a scanning electron microscope and an energy dispersive X-ray analyzer attached to the scanning electron microscope were used to count the number of silicon-containing foreign particles (number / mm2) with a maximum diameter of 0.5 μm to 50 μm and 1 μm to 10 μm. 2 ), and the number of silica particles with a maximum diameter of 0.5 μm to 50 μm and 1 μm to 10 μm (pieces / mm 2 ) was measured. Silicon-containing foreign matter and silica foreign matter of each size were measured twice using different slip sheets, and the average value was calculated.

[0086] The glass plate interleaving papers of Examples 1 to 7 were formed into a size of 2330 mm x 1990 mm, and each had a thickness of 0.5 mm. They were then interposed between glass plates for FPDs having a size of 2250 mm x 1950 mm to form a glass plate laminate in which multiple glass plates were laminated.

[0087] Each glass plate laminate was placed on a pallet stacked vertically as shown in Fig. 2 (600 glass plates), to prepare a glass plate package. The prepared glass plate package was stored for 10 days.

[0088] The glass plate closest to the inclined platform of the pallet was removed from the glass plate package, and the glass plate was washed, and then the number of foreign matters remaining on the surface of the glass plate was counted with an optical inspection machine.

[0089] Each measurement was carried out by the following method.

[0090] <Measurement of elemental concentration in glass sheet interleaving paper using fluorescent X-ray analysis> The approximate center of the interleaf was measured using a fluorescent X-ray analyzer (manufacturer: Rigaku Corporation, model: ZXS PRIMUSII). Next, a reference sample with a known concentration was measured in advance to quantify the detected elements, and the numerical values ​​of each element were corrected from the X-ray intensity. The power for the measurement was 3000W, and the contents of each element, magnesium, aluminum, silicon, and calcium, were quantified.

[0091] <Measurement of the number of silicon-containing and silica-containing foreign particles contained in glass plate interleaving paper> The silicon-containing foreign matter contained in the slip paper was measured at approximately the center of the slip paper using a scanning electron microscope (manufacturer: JEOL Ltd., model: JSM-6490LA) and an energy dispersive X-ray analyzer (manufacturer: Oxford Instruments Ltd., model: X-MAXN50). The accelerating voltage during observation was 20 kV.

[0092] When measuring silicon-containing foreign matter with a maximum diameter of 0.5 μm or more and 50 μm or less, and silica foreign matter, first, 100 areas of 0.1 mm x 0.1 mm were measured, and foreign matter other than carbon with a maximum diameter of 0.5 μm or more was counted. The size of each foreign matter detected by this backscattered electron detector was calculated from the number of pixels, and the elements of each particle with a maximum diameter of 0.5 μm or more and 50 μm or less were analyzed using an energy dispersive X-ray analyzer, and the number of particles containing 10% or more by weight of silicon (silicon-containing foreign matter) and particles containing 80% or more by weight of silicon (silica foreign matter) were counted, among elements excluding carbon and oxygen.

[0093] The same measurement was also performed when measuring silicon-containing foreign matter and silica foreign matter having a maximum diameter of 1 μm or more and 10 μm or less.

[0094] <Measurement and evaluation of foreign matter remaining on the glass plate surface> The glass plate closest to the inclined platform of the pallet was removed from the glass plate package stored for 10 days, and the glass plate was washed and then the number of foreign bodies remaining on the surface of the glass plate was measured using an optical inspection machine (manufacturer: Hitachi High-Tech Fine Systems Co., Ltd., model: GI). The glass plate was washed by rubbing it with a PVA sponge while pouring pure water on it while transporting it horizontally.

[0095] Glass plates with less than 50 foreign objects on their surface were rated as A, between 50 and 60 as B, and 60 or more as C.

[0096] (Example 1, Example 2) A raw material liquid for the slip paper was obtained by diluting virgin pulp with a high calcium content with groundwater filtered through a process filter with a filtration accuracy of 200 μm. The raw material liquid was spread to a uniform thickness and dehydrated to obtain a wet paper. The obtained wet paper was dehydrated by pressing with a press roller, and the pressed wet paper was dried in an atmosphere of about 120 ° C to obtain the slip paper.

[0097] (Example 3, Example 4) The production was carried out in the same manner as in Example 1, except that virgin pulp having a high silicon content was used as the raw material.

[0098] (Example 5) The production was carried out in the same manner as in Example 1, except that virgin pulp having a high silicon content and a low calcium content was used as the raw material.

[0099] (Example 6, Example 7) The production was carried out in the same manner as in Example 1, except that virgin pulp containing talc and having a high concentration of silicon and magnesium was used as the raw material.

[0100] <Result> Table 1 shows the measurement and evaluation results. According to Table 1, when the silicon concentration was 200 ppm or less and the X / Y ratio, which is the silicon concentration divided by the calcium concentration, was 4.00 or less, the contamination level was rated A or B. On the other hand, when the silicon concentration was over 200 ppm and the X / Y ratio was greater than 4.00, the contamination level was always rated C.

[0101] From these results, it can be understood that the silicon concentration and the X / Y ratio are related to the number of silica particles present in the slip sheet and the contamination of the glass plate.

[0102] [Table 1] [Explanation of symbols]

[0103] 10...glass plate package, 12...glass plate laminate, 14...glass plate, 16...glass plate interleaf paper, 18...inclined table, 22...base, 24...mounting table, 42...interleaf paper roll, 100...glass plate interleaf paper manufacturing device, 112...head box, 114...wire part, 116...lower wire, 118...upper wire, 120...press part, 124...dryer part, 126...calendar part, 128...reel, 130...jumbo roll, 134...cutter, 136...winder.

Claims

1. The main component is cellulose pulp. Basis weight: 10g / m ２ Above, 100g / m ２ A glass plate interleaving paper comprising: In the glass plate interleaving paper, when the silicon concentration measured by X-ray fluorescence analysis is X and the calcium concentration measured by Y are: X is 10 ppm or more and 150 ppm or less, Y is 20 ppm or more and 400 ppm or less, 1. A glass plate interleaving paper, characterized in that the X / Y ratio, which is the value obtained by dividing the silicon concentration by the calcium concentration, is 4.00 or less.

2. In the glass plate interleaving paper, when the magnesium concentration measured by fluorescent X-ray analysis is Z, 2. The glass plate interleaving paper according to claim 1, wherein an X / Z ratio, which is a value obtained by dividing a silicon concentration by a magnesium concentration, is 3.00 or less.

3. The glass plate interleaving paper according to claim 2 , wherein Z is 20 ppm or more and 100 ppm or less.

4. The glass plate interleaving paper has a surface area of ​​at least one of the interleaving paper surfaces that is not smaller than 2,000 silicon-containing foreign particles having a size of 0.5 μm or more and not larger than 50 μm or less. ２ The glass plate interleaving paper according to any one of claims 1 to 3, wherein:

5. The glass plate interleaving paper has a surface on at least one side of which the number of silicon-containing foreign particles having a size of 1 μm or more and 10 μm or less is 1,000 pieces / mm ２ The glass plate interleaving paper according to any one of claims 1 to 4, wherein:

6. The glass plate interleaving paper has a surface on at least one side of which the number of silica foreign particles having a size of 0.5 μm or more and 50 μm or less is 100 pieces / mm ２ The glass plate interleaving paper according to any one of claims 1 to 5, wherein:

7. The glass plate interleaving paper has a surface on at least one side of which the number of silica foreign particles having a size of 1 μm or more and 10 μm or less is 50 pieces / mm ２ The glass plate interleaving paper according to any one of claims 1 to 6, wherein:

8. The glass plate interleaving paper has an air resistance of 5 seconds or more. The glass plate interleaving paper according to any one of claims 1 to 7.

9. A glass plate laminate in which at least two glass plates are laminated, A glass plate laminate having the glass plate interleaving paper according to any one of claims 1 to 8 between adjacent glass plates.

10. A glass sheet package comprising: the glass sheet laminate according to claim 9; and a pallet on which the glass sheet laminate is placed.

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