JP2016191180A - Wood pulp for glass plate slip sheet and slip sheet for glass plate - Google Patents

Abstract

A glass plate used as a substrate material for a flat panel display that requires high cleanliness and scratch quality is prevented from being scratched or cracked on the surface of the glass plate even when used in a normal manner as a slip sheet. A slip paper that can be used, and wood pulp for the slip paper are provided. SOLUTION: A wood pulp for glass board plywood having a ratio of aluminum solid inorganic substances present on the surface of handsheets prepared by a method according to JIS P 8222 of 25 pieces / m2 or less, and wood pulp Glass sheet interleaving paper as a raw material, wherein the ratio of aluminum solid inorganic substances present on the surface is 20 pieces / m 2 or less. [Selection figure] None

Description

  The present invention relates to a paper for packaging a glass plate in a process of transporting and storing the glass plate, a paper sandwiched between the glass plates (interleaf paper), and a wood pulp used for manufacturing these papers. is there. In particular, the present invention relates to paper that can be suitably used as glass interleaving paper for flat panel displays such as liquid crystal panel displays, plasma displays, and organic electroluminescence (organic EL) displays.

  In general, in the process of stacking and storing a plurality of glass plates, the distribution process of transporting by a truck, etc., there is a risk that the glass plates will be impacted and contacted to cause cracks and scratches on the surface of the glass plates. .

  In particular, glass plates for flat panels and displays are used for high-definition displays compared to general architectural window glass plates and vehicle window glasses, so the glass surface is clean and free from cracks and scratches. It is required to hold the surface and to have excellent flatness for high-speed response and widening of the viewing angle. For example, even if the surface of the glass plate has minute cracks, scratches, etc., there are problems such as no element being formed at that location and wiring being cut. Therefore, there is a method in which a slip sheet (glass slip sheet) is sandwiched between glass plates for the purpose of preventing breakage, scratches and the like of the glass surface.

  As a glass interleaving paper used in such applications, several interleaving papers that can prevent a glass plate from cracking or scratching the surface, and that do not contaminate the glass surface have been proposed. For example, Patent Document 1 discloses a technique for forming a fluorine coating film on the surface of a slip sheet. Further, in Patent Document 2, a slip sheet in which a polyethylene-based resin foam sheet and a polyethylene-based resin film are bonded is disclosed in Patent Document 3, which is a paper made of pulp containing 50 mass% or more of exposed chemical pulp. In addition, a paper for glass containing a specific alkylene oxide adduct or water-soluble polyether-modified silicone is disclosed in Patent Document 4, which defines the amount of resin in the paper and includes raw materials that are taken into consideration for contamination countermeasures on the glass surface. Each used glass slip is disclosed.

JP 2012-188785 A JP 2010-242057 A JP 2008-208478 A JP 2006-44674 A

  However, even if using slip sheets for the purpose of preventing cracks, scratches, etc. of the glass plate, these cannot be completely prevented, and in some cases, cracks, scratches, etc. on the glass plate surface for some reason, Furthermore, the fact is that the defect rate of the glass plate may increase due to contamination of the glass plate surface.

  In particular, glass plates used for flat panel displays are more prone to breakage and short-circuiting if there are minute cracks and scratches on the surface, or contamination. There is a need for an interleaving paper that gives less cracks and scratches and contamination. Further, since the surface of the glass plate serves as an image display surface, cleanliness and beauty are also required, and from this point, it is necessary that there are few cracks, scratches, contamination, and the like. And if the defect rate rises due to these cracks, scratches, contamination, etc., it becomes a problem from the viewpoint of profitability, so how to prevent cracks, scratches, contamination, etc. on the surface of glass plates used for flat panel displays How to achieve high yield is a big issue.

  Therefore, an object of the present invention is to significantly prevent the glass surface from being cracked, scratched, or contaminated with respect to a glass plate used as a substrate material for a flat panel display that requires high scratch quality.

  For example, when a color filter substrate in an array process, which is one of the TFT liquid crystal display manufacturing processes, is cracked, scratched, or contaminated on the glass plate surface, problems such as disconnection may occur. The color filter substrate is produced by forming a thin film such as a semiconductor film, an ITO film (transparent conductive film), an insulating film, an aluminum metal film, or the like on a glass plate by sputtering or vacuum evaporation, etc. This is because the presence of scratches, contamination, etc. increases the possibility that the circuit pattern formed from the thin film will be disconnected or that a short circuit will occur due to a defect in the insulating film. In the production of the color filter substrate, a photolithography pattern is formed on the glass plate. If there are cracks, scratches, contamination, etc. on the glass plate surface during resist application in this step, the resist film after exposure and development will be exposed. Pinholes and partial defects may occur, resulting in wire breaks and short circuits. The cause of such cracks, scratches, and contamination of the glass plate was difficult to identify, but correlated with the aluminum solid inorganic material present on the surface of the glass interleaving paper and the cracks, scratches, contamination, etc. generated on the surface of the glass plate. It has been found for the first time by the present inventors' verification. In particular, even if this aluminum-based solid inorganic substance is very small, the surface of the glass plate is damaged, and when the glass plate or interleaf paper moves, it is found that the fine scratch remains long as a scar. It was done.

  And the present inventors reduced the aluminum-based solid inorganic substance that could be a problem appearing on the surface of the glass sheet interleaf, or the aluminum contained in the wood pulp used for the production of the glass sheet interleaf. The present invention was completed by finding that the above-mentioned problems can be solved by reducing the amount of the aluminum-based solid inorganic substance, which can be a problem that finally appears on the surface of the glass sheet interleaf. .

The first aspect of the present invention is a wood pulp for glass board interleaving paper,
The present invention relates to a wood pulp for glass plate interleaving paper in which the ratio of aluminum solid inorganic substances present on the surface of handsheets prepared by a method according to JIS P 8222 using the wood pulp is 25 pieces / m ² or less.

  The average particle size of the aluminum-based solid inorganic material is preferably 20 to 300 μm.

  The aluminum-based solid inorganic material may include one or more aluminum-based compounds selected from the group consisting of aluminum hydroxide, aluminum oxide, and aluminum silicate.

  The glass plate is preferably used for a display, and in particular, the display is preferably a TFT liquid crystal display or an organic EL display.

The second aspect of the present invention is a glass sheet interleaf made of wood pulp,
The present invention relates to a slip sheet for glass plate in which the ratio of the aluminum-based solid inorganic substance existing on the surface is 20 / m ² or less.

  The average particle size of the aluminum-based solid inorganic material is preferably 20 to 300 μm.

  The aluminum-based solid inorganic material may include one or more aluminum-based compounds selected from the group consisting of aluminum hydroxide, aluminum oxide, and aluminum silicate.

  The glass plate is preferably used for a display, and in particular, the display is preferably a TFT liquid crystal display or an organic EL display.

  Further, the present invention provides a laminate of the glass plate interleaf made of the wood pulp of the first aspect of the present invention and / or the glass sheet interleaf and the glass plate of the second aspect of the present invention. Also related.

  Furthermore, the present invention relates to the use of the wood pulp of the first aspect of the present invention for the production of a glass sheet interleaving paper, particularly the glass sheet interleaving paper of the second aspect of the present invention, and the first aspect of the present invention. The present invention also relates to a method for protecting a glass plate, including a step of inserting the glass plate interleaf of the second aspect between a plurality of glass plates.

  The glass sheet interleaf made of wood pulp of the present invention and the glass sheet interleaf of the present invention do not cause cracks or scratches on the surface of the glass plate even if they contact the glass plate for a long time, The glass plate surface is not contaminated.

  That is, when the glass plate interleaf made of the wood pulp of the present invention or the interleaf paper of the present invention is used for the glass plate, even if the interleaf is in contact with the glass plate surface, the glass plate surface is cracked, scratched, or contaminated. In particular, the production yield of glass plates for flat panel displays can be improved. And the glass interleaving paper of this invention can suppress generation | occurrence | production of the crack of a glass plate, a damage | wound, contamination, etc. as much as possible. Thereby, for example, it becomes possible to prevent circuit disconnection of a color film or the like in the manufacturing process of the TFT liquid crystal.

When interleaving paper is used on a glass plate, the aluminum-based solid inorganic substance on the surface of the interleaving paper tends to come into contact with the glass plate and cause cracks, scratches, contamination, etc., especially on the surface. Interleaving paper made of wood pulp capable of preparing a paper having a number of aluminum-based solid inorganic substances exceeding 25 / m ² , or a number of aluminum-based solid inorganic substances existing on the surface exceeding 20 / m ² It has now been clarified that the use of interleaving paper for a glass plate significantly increases the fine cracks, scratches, contamination, etc. that occur on the surface of the glass plate, resulting in problems during panel formation.

Therefore, the wood pulp for glass board interleaving paper of the present invention is
The ratio of the aluminum type solid inorganic substance which exists in the surface of the handsheet prepared by the method based on JISP8222 using the said wood pulp is 25 piece / m < ² > or less. 20 / m ² or less is preferable, 15 / m ² or less is more preferable, and 10 / m ² or less is even more preferable.

  The thickness of the handsheet is preferably 0.01 to 2 mm, more preferably 0.05 to 1 mm, and still more preferably 0.05 to 0.2 mm.

The basis weight of the handsheets is preferably 20 to 80 g / ^{m 2,} more preferably from 25~70g / ^{m 2,} and still more preferably from a 30 to 60 g / ^{m 2.}

  The aluminum-based solid inorganic substance contains an aluminum element and is in a solid state. Here, “solid” means a solid state under normal pressure (1 atm) and at normal temperature (25 ° C.). Therefore, the melting point of the aluminum-based solid inorganic substance exceeds 25 ° C., preferably 50 ° C. or higher, more preferably 80 ° C. or higher, and even more preferably 100 ° C. or higher.

  The Mohs hardness of the aluminum-based solid inorganic substance is preferably 4 or more. Mohs hardness is an index of hardness expressed in 10 levels. Rubbing the standard material and the material to be measured against each other, the hardness of the standard material is relatively determined by whether or not it is scratched. It is the evaluated value. The standard materials were soft (Mohs hardness 1) to hard (Mohs hardness 10) in the order of 1: talc, 2: gypsum, 3: calcite, 4: fluorite, 5: apatite, 6: feldspar, 7: quartz 8: Topaz, 9: Corundum, 10: Diamond. The Mohs hardness is measured by preparing two plates with a smooth surface and a known Mohs hardness, sandwiching the aluminum-based solid inorganic material to be measured between the two plates, and rubbing both plates to generate scratches on the plate surface. Check for presence.

  The kind of the aluminum-based solid inorganic substance is not limited, but preferably contains one or more aluminum-based compounds selected from the group consisting of aluminum hydroxide, aluminum oxide, and aluminum silicate.

In the present invention, the volume of the aluminum-based solid inorganic substance is preferably controlled to less than 0.03 mm ^3, more preferably less than 0.01 mm ^3, even more preferably 0.001 mm ^3, 0.0001 mm ³ even more favorable Better. Unlike soils, aluminum-based solid inorganic substances are present as three-dimensional objects on the surface and inside of slip sheets, causing problems. In particular, when the size of the aluminum-based solid inorganic substance is 0.03 mm ³ or more, there is a high possibility that the aluminum-based solid inorganic substance contacts the glass plate surface and leaves scratches or cracks when the glass interleaving paper is used. Tend to be. For example, when laminating a glass interleaving paper and a glass plate, an aluminum solid inorganic substance present on the surface of the interleaving paper may be pressed by the weight of the glass plate, but if the size of the aluminum solid inorganic substance is small Even if pressed, since the aluminum-based solid inorganic substance is buried in the interleaf paper, the possibility of scratching the glass plate surface is reduced. In addition, since the aluminum-based solid inorganic substance is a three-dimensional object as described above, particularly when the projected area is small and there is a height, the aluminum-based solid inorganic substance can be visually observed as scratches generated when the glass or the glass interleaving paper moves. There is a risk of leaving such scratches. On the other hand, if the projected area is large even if the height is low, the surface of the glass plate may be damaged, which is not preferable.

  The aluminum-based solid inorganic substance preferably has an average particle diameter corresponding to a sphere volume diameter of 20 to 250 μm, more preferably 20 to 200 μm, still more preferably 20 to 150 μm, and still more preferably 20 to 100 μm. It is further more preferable that it is 20-50 micrometers. The equivalent sphere volume diameter is the diameter of the sphere when the particles of the aluminum-based solid inorganic substance are converted into spheres having the same volume, and can be measured by a laser diffraction method or the like.

 Wood pulp usable in the present invention includes softwood bleached kraft pulp (NBKP), hardwood bleached kraft pulp (LBKP), softwood bleached sulfite pulp (NBSP), hardwood bleached sulfite pulp (LBSP), and thermomechanical pulp (TMP). These are wood pulps such as single or mixed. Softwood bleached kraft pulp (NBKP) and softwood bleached sulfite pulp (NBSP) are preferred. This wood pulp is the main component, non-wood pulp such as hemp, bamboo, cocoon, kenaf, cocoon, cocoon, cotton etc., modified pulp such as cationized pulp, mercerized pulp, rayon, vinylon, nylon, etc. Synthetic fibers such as acrylic and polyester, chemical fibers, or microfibrillated pulp can be used alone or in combination. However, if the pulp contains a large amount of resin, the resin may contaminate the glass plate surface. Therefore, chemical pulp with as little resin as possible, for example, softwood bleached kraft pulp, is used alone. It is preferable to do. Also, high yield pulp such as groundwood pulp is not preferred because it contains a large amount of resin. In addition, mixing synthetic fibers and chemical fibers improves cutting performance and improves workability when making interleaf paper flat, but care must be taken because recyclability deteriorates in terms of waste disposal. is there.

 In addition, in the range not impairing the performance of the present invention, for the papermaking fiber mainly composed of the above-described wood pulp, if necessary, an adhesive, an antifungal agent, various papermaking fillers, a wet paper strength enhancer, Add dry paper strength enhancer, sizing agent, colorant, fixing agent, yield improver, slime control agent, etc., then known and existing long net paper machine, circular net paper machine, short net paper machine, long net It can be obtained by paper making with a circular net combination paper machine. In addition, when adding these chemicals, extreme caution is required so that insects and dust do not enter.

 When the wood pulp of the present invention is produced, if the beating of the wood pulp is advanced, an effect of increasing the paper interlayer strength can be expected. However, if the fine fibers in the wood pulp increase as the beating progresses, paper dust may be generated during use as a slip sheet, so it is not preferable to advance the beating degree more than necessary. Therefore, a preferable beating degree in the present invention is 300 to 650 mlc. s. f. It is.

In order to make the ratio of the aluminum-based solid inorganic substance present on the surface of the handsheet prepared by the method according to JIS P 8222 using the wood pulp of the present invention to 25 pieces / m ² or less, pulp as a raw material It is important to examine and manage papermaking raw materials such as papermaking chemicals and fillers, and a series of process management including the raw material preparation process to the finishing process at the time of papermaking. It is important not to contain many foreign substances such as aluminum-based solid inorganic substances. By using wood pulp with few foreign substances as a raw material, the wood pulp and glass interleaving paper of the present invention can be produced.

  Generally, various foreign substances are contained in wood pulp. For example, foreign materials derived from wood, which is the raw material for wood pulp, foreign materials derived from cooking chemicals during pulp production, foreign materials derived from chemicals used in unbleached cleaning processes, metallic foreign materials derived from waste paper materials, or used in each process This may be caused by water-derived foreign matter. Therefore, in the present invention, it is important to clean and carefully select the pulp that is the raw material of the glass interleaving paper, and it is necessary to remove foreign matter at a high level.

  In general, in the pulp manufacturing process, pulp obtained by cooking wood chips is delignified, and then the pulp is washed and further bleached. Therefore, first, foreign matters are removed and washed at the stage of wood chips. For example, it is preferable to remove foreign matters such as metal and sand with a known foreign matter removing system such as a tip washer. In the pulp manufacturing process, the purpose of washing after cooking is to remove cooking chemicals, lignin degradation products and colored components remaining in the pulp liquid, but it is also possible to remove foreign substances at the same time. For example, a known method such as a countercurrent cleaning method using various cleaning devices such as a vacuum filter cleaning machine, a pressure drum type filter cleaning machine, a press type cleaning machine, and a diffuser cleaning machine can be employed. In particular, in order to remove foreign substances and improve the cleanness of the pulp, it is preferable to increase the amount of washing water used or to use a multi-stage washing system having two or more rinse washing stages. In addition, it is more preferable not to use the substance which causes a foreign material as chemical | medical agents, such as surfactant used at the time of washing | cleaning, a pH adjuster, a pitch control agent, a chelating agent, and an antifoamer. For example, mineral oil-based antifoaming agents used as antifoaming agents can cause mineral foreign matter in glass interleaving paper, so the amount of mineral oil-based antifoaming agents used can be reduced or replaced with other antifoaming agents. It is preferable.

  There is a bleaching step after the washing step, and it is preferable here to remove foreign matter as much as possible. For example, it is possible to install a cleaning device for each bleaching stage. Also here, a known washing machine can be used. For example, a pressure diffuser, a diffusion washer, a pressure drum washer, a horizontal long washer, a press washing machine, or the like can be used. In particular, by using a plurality of these, various kinds of foreign matters can be highly removed. Although chemicals such as alkalis, acids, chelating agents, surfactants, and antifoaming agents can be added to the washing water, it is preferable not to use chemicals that cause foreign substances. In addition, it is preferable to take measures to prevent contamination by foreign matter between the processes. Moreover, it is preferable to wash | clean with an ultrapure water etc. at the end of a process.

  In the present invention, when used paper pulp is used as a raw material, it is preferable to remove foreign substances such as metals at a high level with a pulper, a screen, a cleaner or the like in the used paper pulp manufacturing process.

  By using the wood pulp of the present invention, a glass plate interleaving paper, particularly the glass plate interleaving paper of the present invention, can be obtained by an ordinary method through a paper making process. Moreover, even if it is normal wood pulp, for example, the above-mentioned foreign substance removal process and / or the foreign substance removal process described later in the paper making process can be performed to obtain the glass plate interleaf of the present invention. it can. Note that calendering, super calendering, soft nip calendering, embossing, and the like may be performed during and / or after production of the glass sheet interleaf. Surface properties and thickness can be adjusted by processing.

The slip sheet for glass plate of the present invention is a slip sheet for glass plate made from wood pulp,
The ratio of the aluminum-based solid inorganic substance present on the surface is 20 pieces / m ² or less. 15 / m ² or less is preferable, 10 / m ² or less is more preferable, and 5 / m ² or less is even more preferable. Thereby, even if it uses the glass plate interleaf of this invention for a glass plate, it forms a micro crack, a crack, contamination, etc. on the glass plate surface, As a result, the problem at the time of panel formation is not caused.

  The glass interleaving paper preferably has a thickness of 0.01 to 2 mm, more preferably 0.05 to 1 mm, and still more preferably 0.1 to 0.5 mm.

The basis weight of the glass plate for inserting paper of the present invention is preferably 20 to 80 g / ^{m 2,} more preferably from 25~70g / ^{m 2,} still to be 30 to 60 g / ^{m 2} from preferable.

  As a cause of contamination of glass interleaving paper, there is contamination in the paper making process. For example, the case where it mixes with the chemicals for papermaking, the case where the raw material of various apparatuses falls and mixes with paper, etc. are mentioned. As a method for removing foreign substances in such a papermaking process, it is preferable to use a dust removing device such as a cleaner or a screen device, or other cleaning devices. In the present invention, known devices can be used for these removal methods, such as centrifugal cleaners, special weight cleaners, medium concentration cleaners, lightweight cleaners, hole screens, slit screens, Jansson screens, flat screens, and other washing machines. Can be used. Moreover, since foreign substances may be mixed in the piping of the stock or white water, it is preferable to keep the piping etc. clean at all times.

  Further, the precipitation of aluminum-based solid inorganic material may be reduced or avoided by adjusting the hot water extraction pH of the glass interleaving paper.

The glass interleaving paper of the present invention preferably has a hot water extraction pH of 3.5 to 6.0 measured according to JIS P-8133. From the slip sheet for glass plate designed in this range, the aluminum-based solid inorganic substance is remarkably reduced. On the other hand, when the hot water extraction pH exceeds 6.0, the aluminum-based solid inorganic substance is increased. Increased tendency to cause problems during formation. This is presumed to be due to the fact that the stable state of aluminum changes depending on the pH of the aqueous solution. Aluminum exists as Al ³⁺ in the acidic region, but tends to precipitate as a solid in the neutral region as aluminum hydroxide. As a result of diligent examination in consideration of this point, the presence of aluminum-based inorganic solids in the glass sheet slip sheet of the present invention is suppressed by designing the hot water extraction pH of the glass sheet slip sheet within the above range. be able to. In addition, when the glass sheet interleaf for which the hot water extraction pH is less than 3.5 is designed, the papermaking conditions are in an extremely acidic region, which causes problems such as poor formation of the interleaf.

  There is no restriction | limiting in particular in the method which makes hot water extraction pH of the glass sheet interleaf paper 3.5-6.0, Various acidic substances or an alkaline substance can be used, for example, manufacture of the interleaf paper for glass sheets It is advisable to adjust the amount of aluminum sulfate that is commonly used during papermaking in the process. In particular, in a normal papermaking environment, when other acidic substances or alkaline substances are not added, it is preferable to add about 0.5 to 3.5 parts by weight of aluminum sulfate with respect to 100 parts by weight of dry cellulose fibers. Of course, the blending amount of aluminum sulfate may be appropriately adjusted according to the pH level of white water before blending aluminum sulfate. The amount of aluminum sulfate is preferably 0.7 to 3.5 parts by weight, more preferably 1.0 to 3.5 parts by weight, based on 100 parts by weight of the dried cellulose fiber, and 1.2 to 3. 5 parts by weight is even more preferred, 1.5 to 3.5 parts by weight is even more preferred, and 2.0 to 3.5 parts by weight is particularly preferred. The pH of the white water after blending with aluminum sulfate is preferably 3.5 to 5.8, more preferably 3.5 to 5.3, even more preferably 3.5 to 4.8, and more preferably 3.5 to 4.6. Particularly preferred.

 When a paper sheet for glass plate is made so as to have a hot water extraction pH in the above range, aluminum in white water is present as aluminum ions in the acidic region, and thus does not precipitate and hardly forms a solid foreign matter in the paper. On the other hand, when white water is in a neutral region, it tends to precipitate as aluminum hydroxide or aluminum oxide. In the process of precipitation of aluminum hydroxide, it further fuses with inorganic ions such as silicate ions in water to form aluminum silicate having a larger volume. These cause solid foreign matters in the slip sheet. Accordingly, examples of the aluminum-based solid inorganic substance include aluminum hydroxide, aluminum oxide, and aluminum silicate. Thus, since the stable state of aluminum changes depending on the pH in water, for example, by adding aluminum sulfate, the amount of aluminum itself increases, but the aluminum-based inorganic substance that is a solid foreign matter in the interleaf is rather reduced.

  In this invention, it is preferable to make the hot water extraction pH of the interleaving paper for glass plates into the range of 3.5-5.5, The range of 3.5-5.0 is more preferable, 3.5-4. A range of 9 is even more preferred. When the hot water extraction pH exceeds 5.0 (especially when the hot water extraction pH exceeds 5.5), it has been transferred to glass in a scene that requires a very high-definition display used for portable terminals and the like. This is because the disconnection portion of the color film, which is caused by a small amount of aluminum-based inorganic matter, is highly conspicuous and is highly likely to be judged as a poor quality.

  The interleaving paper obtained from the wood pulp of the present invention, particularly the glass plate interleaving paper of the present invention, is used by being inserted between the glass plates. For example, the glass sheet interleaving paper is typically inserted one by one between a plurality of glass sheets to form a laminated body as a whole, and the laminated body is a target for storage and transportation. Moreover, you may package a glass plate single-piece | unit or the said laminated body using the slip paper which consists of the wood pulp of this invention, especially the glass plate slip paper of this invention. In this way, the glass plate interleaf of the present invention can be inserted between a plurality of glass plates to protect the glass plate.

  Although it does not specifically limit as a glass plate, It is preferable that it is a glass plate for flat panel displays, such as a plasma display panel, a liquid crystal display panel (especially TFT liquid crystal display panel), and an organic electroluminescent display panel. Fine electrodes, partition walls, etc. are formed on the surface of the glass plate for flat panel displays, but by using the glass interleaving paper of the present invention, cracking, scratches, contamination, etc. on the surface of the glass plate are suppressed or Therefore, even if fine electrodes, partition walls, etc. are formed on the surface of the glass plate, inconveniences due to cracks, scratches, contamination, etc. can be suppressed or avoided, and as a result, display defects are suppressed or avoided. can do.

  In particular, as the size of the display increases, the size and weight of the glass plate for flat panel displays has increased. However, the glass interleaving paper of the present invention improves the surface of such a large or heavy glass plate. Can be protected. In particular, since the surface of the glass interleaving paper of the present invention has very little aluminum-based solid inorganic material, the aluminum-based solid inorganic material can damage the surface of the glass plate even when pressed by a heavy glass plate. Contamination is suppressed or avoided. Therefore, the glass interleaving paper of the present invention can be suitably used for a glass plate for a flat panel display in which surface scratch quality and cleanliness are particularly required.

  That is, since a desired film such as an alignment film is formed on the surface of the glass plate for a flat panel display substrate, the prevention of scratches is greatly required, and the glass surface becomes an image display surface. It is required to be beautiful and beautiful, and since it may be exported to foreign markets, it must also be able to withstand long-term transportation and long-term storage. In this regard, when the present invention is used, even if the glass interleaving paper and the glass plate are in contact with each other for a long time, the glass plate surface is not damaged, the glass plate surface is not contaminated, and further, the glass plate Since no blocking occurs, the above requirements can be met accurately.

  The water content of the glass interleaving paper of the present invention is preferably 2 to 10% by mass, more preferably 3 to 9% by mass, and even more preferably 4 to 8% by mass. If the water content is less than 2% by mass, the glass interleaf itself tends to be charged with static electricity, and a blocking phenomenon due to static electricity occurs between the glass plate and the glass sheet. On the other hand, if the water content exceeds 10% by mass, the dimensional stability may be deteriorated due to a blocking phenomenon with a glass plate due to excessive water content or a decrease in water content during use.

The surface electric resistance value (based on JIS K 6911 1995) of the glass interleaving paper of the present invention is the same as that obtained after conditioning the interleaving paper for 24 hours or more at a temperature of 23 ° C. and a relative humidity of 50%. When measured below, it is preferably in the range of 1 × 10 ⁸ to 1 × 10 ¹³ Ω, more preferably in the range of 5 × 10 ^{8 to} 5 × 10 ¹² Ω, and 1 × 10 ⁹ to 1 × 10. ^Even more preferably within the range of ¹² Ω. When the surface electrical resistance value is less than 1 × 10 ⁸ Ω, the adhesion between the glass plate and the interleaf is reduced, and the handling property may be deteriorated. Furthermore, the surface electrical resistance value being less than 1 × 10 ⁸ Ω means that moisture or a conductive substance (for example, a surfactant) was added more than necessary. Excess moisture may adversely affect the dimensional stability of the glass interleaving paper, and many of the conductive substances are organic substances, so these substances migrate to the surface of the glass plate that comes into contact with them, causing dirt, etc. May cause problems. On the other hand, when the surface electrical resistance value of the glass interleaving paper is a high resistance value exceeding 1 × 10 ¹³ Ω, it becomes easy to be charged with static electricity, and the interleaving paper is in close contact with the surface of the glass plate that is in contact with the glass interleaving paper, which significantly impairs handling. There is a fear. Examples of a method for adjusting the surface electrical resistance value to a desired range include moisture adjustment by drying or the like.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely using an Example and a comparative example, the scope of the present invention is not limited to an Example.

[Transfer test method to glass plate (transport test)]
Aluminum foam is placed on the glass mounting surface on the L-shaped gantry at an angle of 75 degrees, and the mounting surface for mounting the glass plate vertically, and the rear end of the mounting surface Insert 120 sheets of glass plate of size 680mm x 880mm x 0.7mm and each glass plate into the backrest surface extending in the vertical direction, and lean it so that it is parallel to the backrest surface and fix it to the gantry The belt-shaped belt thus formed was stretched over the entire circumference from the rear end portion to the backrest surface, and the glass plate was fixed. The gantry set as described above was entirely covered with a packaging material in order to prevent dust and dirt from entering from the outside. After that, a truck transportation test was conducted. The transportation test was conducted at a transportation distance of 1000 km (stored for 5 days in an environment of 40 ° C. × 95% RH during transportation).

[Measurement method of aluminum-based solid inorganic substances]
Four samples were prepared by cutting the glass sheet interleaf paper into 30 cm × 100 cm, and this was suspended (so as to be vertical when viewed from the ground). Both surfaces of the interleaving paper were each washed with 150 mL of ultrapure water from above, and the washed water was collected and filtered through a membrane filter (pore diameter 10 μm). This filtrate was observed with an electron microscope, and foreign matters having a particle size of 20 μm or more were subjected to EDS analysis to measure the number of aluminum-based solid inorganic substances. In addition, when an infinite number of foreign substances existed, 50 foreign substances that were considered to be inorganic solids were observed, and among them, the number ratio of aluminum-based solid inorganic substances was calculated.

[Example 1] (Production of wood pulp)
Washing with ultrapure water 4 times after bleaching process in a conifer bleached kraft pulp manufacturing equipment consisting of a cooking process, a washing process, an oxygen delignification reaction process, and a multistage bleaching bleaching process with chlorine dioxide and hydrogen peroxide Repeated. As described above, softwood bleached kraft pulp A was obtained. Handsheets were produced by a method based on JIS P 8222 using this softwood bleached kraft pulp A as a raw material. The aluminum-based solid inorganic substance present on the surface of the handsheet was 9.3 / m ² .

[Comparative Example 1] (Manufacture of wood pulp)
Conifer bleached kraft pulp B was obtained in the same manner as above except that the washing with ultrapure water was not performed. Handsheets were produced by a method based on JIS P 8222 using this softwood bleached kraft pulp B as a raw material. The aluminum-based solid inorganic substance present on the surface of this handsheet was 27.9 / m ² .

[Example 2] (Production of glass plate interleaving paper)
As a wood pulp, 100 parts by mass of the kraft pulp A of the conifer of Example 1 was prepared, and this was disaggregated to give a beating degree of 520 mlc. s. f. 0.5 parts by weight of polyacrylamide (trade name: Polystron 1250, manufactured by Arakawa Chemical Industries, Ltd.) as a paper strength enhancer was added to the prepared slurry, and a pulp slurry having a concentration of 0.4% by weight. Was prepared. Furthermore, sulfuric acid was added to this pulp slurry to adjust the pH of the pulp slurry to 5.6. This was used to obtain a glass sheet plywood having a basis weight of 50 g / m ² using a long paper machine. The number of aluminum-based solid inorganic substances present on the surface of this glass sheet interleaf was 3.7 / m ² .

[Comparative Example 2] (Production of glass plate interleaving paper)
100 parts by weight of the softwood bleached kraft pulp B of Comparative Example 1 was prepared as a wood pulp, which was disaggregated to give a beating degree of 520 mlc. s. f. 0.5 parts by weight of polyacrylamide (trade name: Polystron 1250, manufactured by Arakawa Chemical Industries, Ltd.) as a paper strength enhancer was added to the prepared slurry, and a pulp slurry having a concentration of 0.4% by weight. Was prepared. The pH of this pulp slurry was 6.6. This was used to obtain a glass sheet plywood having a basis weight of 50 g / m ² using a long paper machine. The aluminum-based solid inorganic substance present on the surface of the glass plate interleaf paper was 24.1 pieces / m ² .

  When the transfer of the glass plate interleaving paper obtained in Example 2 and Comparative Example 2 to the glass plate was confirmed by a transportation test, an array of a liquid crystal panel using the glass plate using the interleaving paper of Example 2 was formed. No disconnection of the color film was observed. On the other hand, when forming an array of a liquid crystal panel using a glass plate using the interleaving paper of Comparative Example 2, disconnection of the color film was observed.

Claims (14)

Wood pulp for glass board interleaving paper,
Wood pulp for glass plate interleaving paper, wherein the ratio of aluminum solid inorganic substances present on the surface of handsheets prepared by a method based on JIS P 8222 using the wood pulp is 25 pieces / m ² or less.   The wood pulp for glass board plywood according to claim 1, wherein the average particle diameter of the aluminum-based solid inorganic substance is 20 to 300 µm.   The wood pulp for glass board plywood according to claim 1 or 2, wherein the aluminum-based solid inorganic substance contains one or more aluminum-based compounds selected from the group consisting of aluminum hydroxide, aluminum oxide, and aluminum silicate.   The said glass plate is for displays, The wood pulp for glass plate interleaving paper according to any one of claims 1 to 3.   The wood pulp for glass board interleaving paper according to claim 4, wherein the display is a TFT liquid crystal display or an organic EL display.   A glass plate interleaving paper comprising the wood pulp for glass plate interleaving paper according to any one of claims 1 to 5.   Use of the wood pulp according to any one of claims 1 to 5 for the production of glass board interleaving paper. It is a slip sheet for glass plate made from wood pulp,
A slip sheet for glass plate having a ratio of aluminum solid inorganic substance existing on the surface of 20 pieces / m ² or less.   The slip sheet for glass plates of Claim 8 whose average particle diameters of the said aluminum-type solid inorganic substance are 20-300 micrometers.   The slip sheet for glass plates according to claim 8 or 9 in which said aluminum system solid inorganic substance contains one or more sorts of aluminum system compounds chosen from the group which consists of aluminum hydroxide, aluminum oxide, and aluminum silicate.   The said glass plate is for displays, The slip sheet for glass plates in any one of Claims 8 thru | or 10.   The slip sheet for glass plates according to claim 11, wherein the display is a TFT liquid crystal display or an organic EL display.   The laminated body which consists of the paper for glass plates in any one of Claims 8 thru | or 12, and a glass plate.   The protection method of a glass plate including the process of inserting the interleaving paper for glass plates in any one of Claims 8 thru | or 12 between several glass plates.