JP6519737B2 - Wood pulp for glass interleaf and paper for glass - Google Patents

Description

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

  Generally, in the process of stacking and storing a plurality of glass sheets, the distribution process carried by a truck, etc., there is a possibility that the glass sheets receive an impact and come in contact, and the surface of the glass sheet may be cracked or scratched. .

  In particular, glass plates for flat panels and displays are used for high-definition displays as compared to general window glass plates for buildings, window glass for vehicles, etc., so the glass surface is clean with no cracks or scratches. It is required to maintain the surface and to have excellent flatness for high-speed response and widening of the viewing angle. For example, even if there are minute cracks, scratches, etc. on the surface of the glass plate, there is a problem that no element is formed at the relevant portion, the wiring is cut, etc. Therefore, there is a method of sandwiching an interleaf (glass interleaf) between glass plates for the purpose of preventing a crack, a crack, etc. of the glass surface.

  As a glass interleaving paper used in such applications, some interleaving papers which can prevent breakage of a glass plate or surface damage, and some interleaving papers which do not contaminate a glass surface are proposed. For example, Patent Document 1 discloses a method of forming a fluorine coating film on the surface of an interleaf. Further, in Patent Document 2, a paper made of pulp containing 50% by mass or more of exposed chemical pulp is disclosed in Patent Document 3 in which the polyethylene resin foamed sheet and the polyethylene resin film are bonded. Patent Document 4 specifies the amount of resin in the paper, and a raw material in consideration of the prevention of contamination of the glass surface is disclosed in Patent Document 4 as a paper insert for glass containing a specific alkylene oxide adduct and a water-soluble polyether-modified silicone. The glass interleaf used is each disclosed.

JP 2012-188785 A JP, 2010-242057, A JP, 2008-208478, A Unexamined-Japanese-Patent No. 2006-44674

  However, even if the interleaf is used for the purpose of preventing cracks, scratches, etc. of the glass plate, these can not be completely prevented, and in some cases, the cracks, scratches, etc. of the surface of the glass plate due to any cause Furthermore, it is a fact that the defect rate of the glass plate may increase due to the contamination of the surface of the glass plate.

  In particular, glass plates used for flat panel displays are more likely to be used as glass plates than conventional glass interleaf paper, because the possibility of breakage or short circuiting increases when minute cracks and flaws or contamination are present on the surface. There is a need for paper that is less susceptible to cracking and scratching and contamination. In addition, since the surface of the glass plate is an image display surface, it is also required to be beautiful and beautiful, and from this point as well, it is necessary that the number of cracks, scratches, contamination and the like be small. And if the defect rate rises due to these cracks, scratches, contamination, etc., it also becomes a problem from the viewpoint of profitability, so how to prevent the cracks, scratches, contamination etc. on the surface of the glass plate used for flat panel display How to achieve high yield is a big issue.

  Then, this invention makes it a subject to prevent the crack of a glass surface, a crack, a contamination, etc. remarkably about the glass plate used as a substrate material for flat panel displays for which high flaw quality is required.

  For example, when there are cracks, scratches, contamination, etc. on the surface of the glass plate at the time of producing the color filter substrate in the array process which is one of the manufacturing steps of the TFT liquid crystal display, 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, or an aluminum metal film on a glass plate by sputtering or vacuum evaporation. This is because there is a high possibility that a circuit pattern formed of a thin film may be broken or a short circuit may occur due to a defect of an insulating film if there are scratches, contamination, and the like. Also, in the preparation of the color filter substrate, a pattern by photolithography is formed on the glass plate, but if cracks, scratches, contamination, etc. exist on the glass plate surface at the time of resist application in this step, the resist film after exposure or development Pin holes or partial defects may occur, resulting in disconnection or short circuit. Although it was difficult to identify the cause of such cracks, scratches, and contamination on the glass plate, it is correlated with the aluminum solid inorganic material present on the surface of the glass interleaf and the cracks, scratches, and contamination generated on the surface of the glass plate. It has been found for the first time by the present inventors that there is In particular, it has been found that even if this aluminum-based solid inorganic substance is minute, it damages the surface of the glass plate and causes scratches when the glass plate and interleaf move, so that fine scratches remain long as scars. It was done.

  And the present inventors are aluminum contained in wood pulp used for manufacture of a paper for a glass plate by reducing the aluminum-based solid inorganic substance which may become a problem appearing on the surface of the paper for a glass plate. It has been found that the above-mentioned problems can be solved by reducing the amount of aluminum-based solid inorganic materials which can finally become a problem appearing on the surface of the interleaf paper for glass plates by reducing the amount of the solid inorganic materials, and completed the present invention .

A first aspect of the present invention is wood pulp for glass interlaying,
The present invention relates to a wood pulp for glass interleaf, wherein the ratio of the aluminum-based solid inorganic substance present on the surface of a handsheet prepared using the wood pulp by the method according to JIS P 8222 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 for a display, and in particular, the display is preferably a TFT liquid crystal display or an organic EL display.

A second aspect of the present invention is a paper for paper for glass plates, which is made of wood pulp,
The present invention relates to a glass interleaf, wherein the ratio of the aluminum-based solid inorganic substance present 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 for a display, and in particular, the display is preferably a TFT liquid crystal display or an organic EL display.

  Further, the present invention relates to a glass sheet in the form of wood pulp according to the first aspect of the present invention, and / or a laminate of the glass sheet in the second aspect of the present invention and the glass sheet. Also related.

  Furthermore, the present invention relates to the use of the wood pulp according to the first aspect of the present invention for the production of a glass sheet, particularly the glass sheet according to the second aspect of the present invention, and The present invention also relates to a method for protecting a glass sheet, which comprises the step of inserting the glass sheet of the second embodiment between a plurality of glass sheets.

  The glass plate interleaving paper comprising the wood pulp of the present invention and the glass plate interleafing paper of the present invention do not cause problems such as cracking or scratching on the surface of the glass plate even after prolonged contact with the glass plate, It does not contaminate the glass plate surface.

  That is, when the glass plate interleaving paper made of wood pulp of the present invention or the interleaving paper of the present invention is used for a glass plate, even if the interleaving paper comes in contact with the surface of the glass plate This can improve the production yield of glass plates for flat panel displays in particular. And the glass interleaving paper of this invention can suppress generation | occurrence | production of the crack of a glass plate, a crack, contamination, etc. as much as possible. As a result, it becomes possible to prevent, for example, disconnection of a circuit such as a color film in the manufacturing process of the TFT liquid crystal.

When an interleaf paper is used for a glass plate, the aluminum-based solid inorganic substance on the surface of the interleaf paper is in contact with the glass plate and tends to cause cracks, scratches, contamination and the like of the glass plate. A paper made of wood pulp capable of preparing paper in which the number of aluminum-based solid inorganic substances is more than 25 / m ² , or the number of aluminum-based solid inorganic substances present on the surface is more than 20 / m ² It has become clear that the use of interleaf paper as a glass plate significantly increases micro cracks, scratches, contamination and the like generated on the surface of the glass plate, resulting in problems when forming a panel.

Accordingly, the wood pulp for glass interleaf according to the present invention is
The ratio of the aluminum-based solid inorganic substance present on the surface of handsheets prepared by the method according to JIS P 8222 using the wood pulp is 25 pieces / m ² or less. 20 pieces / m < ² > or less are preferable, 15 pieces / m < ² > or less are more preferable, 10 pieces / m < ² > or less are still 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 being in a solid state under normal pressure (1 atm) and normal temperature (25 ° C). Therefore, the melting point of the aluminum-based solid inorganic substance exceeds 25 ° C., preferably 50 ° C. or more, more preferably 80 ° C. or more, and still more preferably 100 ° C. or more.

  The Mohs hardness of the aluminum-based solid inorganic substance is preferably 4 or more. The Mohs hardness is an index of hardness expressed in 10 steps, and the corresponding standard substance and the substance to be measured are rubbed, and the hardness relative to the standard substance is relatively determined depending on whether or not it is damaged. It is the evaluated value. The standard substances are soft (in Mohs hardness 1) to hard (in Mohs hardness 10), 1: talc, 2: gypsum, 3: calcite, 4: fluorite, 5: apatite, 6: feldspar, 7: quartz , 8: Topaz, 9: Corundum, 10: Diamond. The method of measuring Mohs hardness prepares two plates with a smooth surface known Mohs hardness, sandwiches the aluminum solid inorganic material to be measured between the two plates, rubs both plates together and generates scratches on the plate surface Examine the presence or absence.

  Although the type of the aluminum-based solid inorganic substance is not limited, it is preferable to include 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 dirt, aluminum-based solid inorganic substances cause problems because they are present on the surface and the inside of a paper as three-dimensional objects. 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 with the surface of the glass plate and leaves scratches or cracks when the glass interleaf is used. Tend to For example, when laminating a glass interleaving paper and a glass plate, the aluminum-based solid inorganic material present on the surface of the paper may be pressed by the weight of the glass plate, but if the size of the aluminum-based solid inorganic material is small Since the aluminum-based solid inorganic material is buried in the paper of the interleaf even when pressed, the possibility of damaging the surface of the glass plate 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 even if the height is high, it can be visually recognized as a scratch generated when the glass or glass interleaf is moved. There is a risk of leaving such scratches. Conversely, if the projected area is large even if the height is low, the surface of the glass plate may be damaged, which is also not preferable.

  The aluminum-based solid inorganic material preferably has an average particle 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, and it is especially preferable that it is 20-50 micrometers. The sphere volume equivalent diameter is the diameter of the sphere when the particles of the aluminum-based solid inorganic material are converted to spheres of the same volume, and can be measured by a laser diffraction method or the like.

 Wood pulp usable in the present invention is softwood bleached kraft pulp (NBKP), hardwood bleached kraft pulp (LBKP), softwood bleached sulfite pulp (NBSP), hardwood bleached sulfite pulp (LBSP), thermomechanical pulp (TMP) Etc. wood pulp alone or mixed. Softwood bleached kraft pulp (NBKP) and softwood bleached sulfite pulp (NBSP) are preferred. The main component of this wood pulp is, if necessary, non-wood pulp such as hemp, bamboo, rattan, kenaf, rattan, Mitaka or cotton, cationized pulp, modified pulp such as mercerized pulp, rayon, vinylon, nylon, Synthetic fibers such as acrylic and polyester or chemical fibers, or microfibrillated pulp can be used alone or in combination. However, if a large amount of resin is contained in the pulp, the resin may adversely affect the surface of the glass plate or the like. Therefore, chemical pulp with as little resin as possible, such as softwood bleached kraft pulp, is used alone. It is preferable to do. Moreover, high-yield pulp such as ground pulp is not preferable because it contains a large amount of resin. In addition, if synthetic fibers and chemical fibers are mixed, cutting performance will be improved, and the workability in making a plain paper will be improved, but in terms of waste disposal, the recyclability will be worse, so care must be taken. is there.

 In addition, an adhesive, a mildew proofing agent, various paper making fillers, a wet paper strengthening agent, if necessary, for papermaking fibers mainly composed of wood pulp described above, as long as the performance of the present invention is not impaired. Dry strength agent, sizing agent, coloring agent, fixing agent, retention aid, slime control agent, etc. are added, and then known and existing Fourdrinier Paper Machine, Circular Mesh Paper Machine, Fourdrinier Paper Machine, and Fourdrinier It can be obtained by paper making with a combination paper machine or the like of a circular net. In addition, when adding these medicines, it is necessary to be careful not to mix insects and refuse.

 When the wood pulp of the present invention is produced, if the wood pulp is refined, the effect of increasing the strength between paper layers can be expected. However, if fine fibers in the wood pulp are increased by advancing the beating, there is a possibility that paper dust may be generated during use as interleaf, it is not preferable to advance the degree of beating more than necessary. Therefore, in the present invention, the preferred freeness 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 a handsheet prepared by the method according to JIS P 8222 using the wood pulp of the present invention 25 pieces / m ² or less, the pulp as a raw material It is important to consider and control the raw materials for papermaking, such as chemicals for papermaking and fillers, and a series of process control including the whole process from the preparation process of the raw materials at the time of papermaking to the finishing process. It is important not to contain much 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 interleaf paper of the present invention can be manufactured.

  In general, various foreign substances are contained in wood pulp. For example, foreign substances derived from wood, which are raw materials of wood pulp, foreign substances derived from digesting chemicals at the time of pulp production, foreign substances derived from chemicals used in unbleached washing process, metal foreign substances derived from waste paper raw material, or used in each process And foreign substances derived from water. Therefore, in the present invention, it is important to wash and select the pulp, which is a raw material of glass interleaf, and it is necessary to remove foreign matter at a high level.

  Generally, in the process of pulp production, pulp obtained by digesting wood chips is delignified and then the pulp is washed and further bleached. Therefore, foreign matter is removed and cleaned at the wood chip stage. For example, it is preferable to remove foreign matter such as metal and sand by a known foreign matter removal system such as a chip washer. In the pulp manufacturing process, the purpose of washing after digestion is to remove the digestion chemical solution remaining in the pulp solution, lignin degradation products and colored components, but it is also possible to simultaneously remove foreign matter. For example, known methods such as a countercurrent cleaning method using various cleaning devices such as a vacuum type filter cleaning device, a pressure drum type filter cleaning device, a press type cleaning device and a diffuser cleaning device can be adopted. In particular, in order to remove foreign matter and improve the cleanliness of the pulp, it is preferable to increase the amount of washing water to be used or to use a multistage washing method having two or more rinse 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, an antifoamer. For example, mineral oil antifoaming agents used as antifoaming agents can cause mineral foreign substances in glass paper, so the amount of mineral oil antifoaming agents used can be reduced or replaced with other antifoaming agents. Is preferred.

  After the washing step, there is a bleaching step, and here too, it is preferable to remove foreign matter as much as possible. For example, a washing apparatus may be provided for each bleaching stage. Here, well-known washers can be used, such as pressure diffusers, diffusion washers, pressurized drum washers, horizontal long mesh washers, press washers and the like. In particular, by using a plurality of these, various foreign substances 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 substances that cause foreign substances. In addition, it is preferable to take measures to prevent the entry of foreign matter between each step. Moreover, it is preferable to wash | clean with an ultrapure water etc. at the end of a process.

  When waste paper pulp is used as a raw material in the present invention, in the waste paper pulp production process, it is preferable to remove foreign matter such as metal at a high level with a pulper, screen, cleaner or the like.

  The wood pulp of the present invention can be used to obtain a glass interleaf, in particular, the glass interleaf of the present invention, by a conventional method involving a paper making process. In addition, even with ordinary wood pulp, for example, the glass sheet interleaving paper of the present invention can be obtained by performing the above-mentioned foreign matter removing treatment and / or performing the foreign matter removing treatment described later in the paper making process. it can. In the middle and / or after manufacture of the glass sheet, the calendering process, the super calendering process, the soft nip calendering process, the embossing process and the like may be performed. The surface property and thickness can be adjusted by processing.

The glass sheet paper of the present invention is a glass sheet paper for wood pulp as a raw material, and
The ratio of the aluminum-based solid inorganic substance present on the surface is 20 / m ² or less. 15 pieces / m < ² > or less are preferable, 10 pieces / m < ² > or less are more preferable, and 5 pieces / m < ² > or less are still more preferable. Thereby, even if it is used for a glass plate, the glass interleaf paper of the present invention forms minute cracks, scratches, contamination and the like on the surface of the glass plate, and as a result, there is no problem in forming a panel.

  The thickness of the glass interleaving paper is preferably 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 for the foreign matter to be mixed in the glass interleaving paper, there is mixing in the paper making process. For example, it may be mixed into paper-making chemicals, or the material of various devices may fall off and be mixed into paper. As a method of removing foreign matter in such a paper making process, it is preferable to use a dust removing device such as a cleaner or a screen device or other cleaning device. In the present invention, known devices can be used for these removal methods, for example, centrifugal cleaner, special weight cleaner, medium density cleaner, light weight cleaner, hall screen, slit screen, Janson screen, flat screen, other cleaning machines, etc. It can be used. In addition, since there is a possibility that foreign matter may be mixed from inside the stock and white water piping, it is preferable to keep the piping and the like clean at all times.

  Moreover, the hot water extraction pH of the glass interleaving paper may be adjusted to reduce or avoid the precipitation of the aluminum-based solid inorganic substance.

It is preferable that the hot-water extraction pH measured based on JISP-8133 of the glass interleaving paper of this invention is 3.5-6.0. While the aluminum-based solid inorganic material decreases remarkably from the interleaf paper for glass plate designed in this range, the aluminum-based solid inorganic material increases when the hot water extraction pH exceeds 6.0, and as a result, the panel The tendency to cause problems during formation increases. This is presumed to be due to the fact that aluminum changes its stability depending on the pH of the aqueous solution. Aluminum is present as Al ³⁺ in the acidic region, but it becomes aluminum hydroxide in the neutral region and tends to precipitate as a solid. As a result of earnestly examining in consideration of this point, the hot water extraction pH of the paper for paper for glass plate is designed in the above range to suppress the presence of the aluminum-based inorganic solid in the paper for paper for glass of the present invention be able to. In addition, when the hot water extraction pH designs an interleaving paper for glass plates below 3.5, since papermaking conditions become an extreme acidic area, problems, such as a formation of an interleaving paper becoming worse, arise.

  There is no particular limitation on the method for setting the hot water extraction pH of the interleaf paper for glass plate to 3.5 to 6.0, and various acidic substances or alkaline substances can be used, for example, manufacture of interleaf paper for glass plate The internal addition amount of aluminum sulfate generally used at the time of papermaking in the process may be adjusted. In particular, in a normal papermaking environment, when no other acidic substance or alkaline substance is added, about 0.5 to 3.5 parts by weight of aluminum sulfate may be added to 100 parts by weight of dry cellulose fiber. Of course, the compounding amount of aluminum sulfate may be appropriately adjusted depending on the degree of the pH of the white water before the compounding of the 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, and more preferably 1.2 to 3 parts by weight with respect to 100 parts by weight of cellulose fibers in a dry state. 5 parts by weight is further more preferable, 1.5 to 3.5 parts by weight is even more preferable, and 2.0 to 3.5 parts by weight is particularly preferable. The pH of white water after blending with aluminum sulfate is preferably 3.5 to 5.8, more preferably 3.5 to 5.3, still more preferably 3.5 to 4.8, and 3.5 to 4.6. Particularly preferred.

 When paper for paper for glass plates is made to have a hot water extraction pH in the above range, aluminum in white water is present as aluminum ions in the acidic region, so it does not precipitate and it is difficult to become solid foreign matter in paper. On the other hand, if the white water is in the neutral region, it tends to precipitate as aluminum hydroxide or aluminum oxide. Then, in the process of precipitation of aluminum hydroxide, it is further fused with inorganic ions such as silicate ions in water to form aluminum silicate or the like having a larger volume. These cause solid foreign matter in the interleaf. Accordingly, examples of the aluminum-based solid inorganic substance include aluminum hydroxide, aluminum oxide and aluminum silicate. Thus, since aluminum changes its stable state depending on the pH in water, the addition of aluminum sulfate, for example, increases the amount of aluminum itself, but rather reduces the amount of aluminum foreign matter which is a solid foreign matter in the paper.

  In the present invention, it is preferable to set the pH of the hot water extraction paper for glass sheet to 3.5 to 5.5, more preferably 3.5 to 5.0, and 3.5 to 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 was transferred to glass in a scene that requires a very high-definition display used for mobile terminals etc. This is because there is a high possibility that the broken portion of the color film, which is generated due to a small amount of aluminum-based inorganic substance, is conspicuous because of high definition and that the quality is judged to be poor.

  The paper obtained from the wood pulp of the present invention, in particular the glass board paper of the present invention, is used by being inserted between the glass sheets. For example, the glass interleaf sheets are typically inserted one by one between a plurality of glass plates, and the whole is made into a laminate, and the laminate becomes an object of storage and transportation. Moreover, you may package the glass plate single-piece | unit or the said laminated body using the paper consisting of the wood pulp of this invention, especially the glass board paper of this invention. Thus, the glass sheet of the present invention can be inserted between a plurality of glass sheets to protect the glass sheets.

  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. Although fine electrodes, partitions, etc. are formed on the surface of the glass plate for flat panel display, by using the glass interleaf of the present invention, cracking, scratches, contamination, etc. of the surface of the glass plate are suppressed Since it is avoided, even if fine electrodes, partitions and the like are formed on the surface of the glass plate, it is possible to suppress or avoid the inconvenience due to cracking, flaws, contamination and the like, and as a result, the defects of the display are suppressed or avoided. can do.

  In particular, although the size and weight of the glass plate for flat panel displays are increasing with the increase in size of the display, the glass interleaf of the present invention makes the surface of such a large to heavy glass plate good. Can be protected. In particular, since the surface of the glass interleaving paper of the present invention is extremely low in aluminum-based solid inorganic substance, the aluminum-based solid inorganic substance damages the surface of the glass plate even when pressed by a heavy glass plate; Contamination is controlled 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 the scratch quality and cleanliness of the surface are particularly required.

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

  The moisture 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 still more preferably 4 to 8% by mass. If the water content is less than 2% by mass, it is not preferable because the glass interleaf itself tends to be charged with static electricity and a blocking phenomenon due to static electricity occurs with the glass plate. On the other hand, when 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 during use.

The surface electrical resistance value (according to JIS K 6911 1995) of the glass interleaf according to the present invention is the same as that after conditioning the interleaf under conditions of a temperature of 23 ° C. and a relative humidity of 50% for 24 hours or more. When measured below, it is preferable to be in the range of 1 × 10 ⁸ to 1 × 10 ¹³ Ω, and more preferable to be in the range of 5 × 10 ^{8 to} 5 × 10 ¹² Ω, and 1 × 10 ⁹ to 1 × 10 ^Even more preferably in the range of ¹² Ω. If the surface electrical resistance value is less than 1 × 10 ⁸ Ω, the adhesion between the glass plate and the interleaf paper is lowered, and the handling property may be deteriorated. Furthermore, that the surface electrical resistance value is less than 1 × 10 ⁸ Ω means that water or a conductive substance (eg, surfactant) is added more than necessary. Excess moisture may adversely affect the dimensional stability of the glass interleaf, and since many of the conductive substances are organic substances, these substances migrate to the surface of the glass plate to be in contact, causing stains, etc. May cause problems. On the other hand, when the surface electrical resistance value of the glass interleaf becomes a high resistance value exceeding 1 × 10 ¹³ Ω, it becomes easy to be electrostatically charged, and the interleaf adheres to the surface of the contacting glass plate and the handling property is significantly impaired. There is a fear. As a method of adjusting surface electrical resistance value to a desired range, moisture adjustment by drying etc. is mentioned, for example.

  Hereinafter, the present invention will be more specifically described using examples and comparative examples, but the scope of the present invention is not limited to the examples.

[Transfer test method to glass plate (transport test)]
Place the urethane foam on the glass mounting surface on the L-shaped mount made of aluminum with an angle of 75 degrees, and from the rear end of the mounting surface for mounting the glass plate in the vertical direction Insert a glass interleaf sheet between 120 glass plates of size 680 mm × 880 mm × 0.7 mm and each glass plate facing the vertically extending back surface, stand parallel to the back surface, and fix it to a gantry The belt-shaped belt thus obtained was stretched from the rear end to the back surface all around to fix the glass plate. The frame set as described above was covered on the entire surface with a packaging material to prevent the mixture of dust and dust from the outside. After that, a truck transport test was conducted. The transportation test conditions were carried out at a transportation distance of 1000 km (stored for 5 days in an environment of 40 ° C. × 95% RH during transportation).

[Method of measuring aluminum-based solid inorganic substance]
Four pieces of paper cut into 30 cm × 100 cm were prepared and suspended (vertically as viewed from the ground). Both sides of the paper were washed from above with 150 mL of ultrapure water, respectively, and the water after washing was collected and filtered with a membrane filter (pore diameter: 10 μm). The residue was observed with an electron microscope, the foreign matter having a particle diameter of 20 μm or more was subjected to EDS analysis, and the number of aluminum-based solid inorganic substances was measured. In addition, when the foreign material existed innumerably, 50 foreign materials considered to be an inorganic solid were observed, and the number ratio of the aluminum-based solid inorganic material was calculated among them.

[Example 1] (Manufacture of wood pulp)
In a softwood bleached kraft pulp manufacturing apparatus consisting of a digestion process, a washing process, an oxygen delignification reaction process, and a multistage bleach-bleaching process with chlorine dioxide and hydrogen peroxide, washing with ultrapure water four times after the bleaching process I repeated it. As described above, softwood bleached kraft pulp A was obtained. Handsheets were produced using this softwood bleached kraft pulp A as a raw material according to JIS P 8222. The aluminum-based solid inorganic substance present on the surface of this handsheet was 9.3 pieces / m ² .

Comparative Example 1 (Production of wood pulp)
Softwood-bleached kraft pulp B was obtained in the same manner as described above except that the washing with ultrapure water was not performed. Handsheets were produced using the softwood bleached kraft pulp B as a raw material according to JIS P8222. The aluminum-based solid inorganic substance present on the surface of this handsheet was 27.9 pieces / m ² .

[Example 2] (Manufacture of glass interleaf)
100 parts by mass of softwood bleached kraft pulp A of Example 1 was prepared as wood pulp, and this was disintegrated to give a beating degree of 520 mlc. s. f. Polyacrylamide (trade name: Polistron 1250, manufactured by Arakawa Chemical Industries, Ltd.) as a paper strengthening agent is added to the slurry prepared above to 0.5 parts by mass with respect to the total pulp mass, and a 0.4 mass% pulp slurry is prepared Prepared. Further, sulfuric acid was added to the pulp slurry to adjust the pH of the pulp slurry to 5.6. The resulting product was used to form a glass interleaf with a basis weight of 50 g / m ² using a Fourdrinier paper machine. The aluminum-based solid inorganic substance present on the surface of this glass interleaf was 3.7 pieces / m ² .

[Comparative example 2] (Manufacture of a glass interleaf)
100 parts by mass of softwood bleached kraft pulp B of Comparative Example 1 was prepared as wood pulp, and this was disintegrated to give a beating degree of 520 mlc. s. f. Polyacrylamide (trade name: Polistron 1250, manufactured by Arakawa Chemical Industries, Ltd.) as a paper strengthening agent is added to 0.5 wt. Prepared. The pH of this pulp slurry was 6.6. The resulting product was used to form a glass interleaf with a basis weight of 50 g / m ² using a Fourdrinier paper machine. The aluminum-based solid inorganic substance present on the surface of this glass interleaf was 24. 1 / m ² .

  Transfer of the glass interleaf obtained in Example 2 and Comparative Example 2 to the glass plate was confirmed by a transportation test. In the case of forming an array of a liquid crystal panel using the glass in which the interleaf of Example 2 was used There was no break in the color film. On the other hand, in the case of the array formation of the liquid crystal panel using the glass plate using the paper of the comparative example 2, the disconnection of the color film was recognized.

Claims (12)

Wood pulp for glass interlaying paper,
1 type selected from the group consisting of aluminum hydroxide, aluminum oxide and aluminum silicate having a particle diameter of 20 μm or more , which is present on the surface of a handsheet prepared by the method according to JIS P 8222 using the wood pulp Wood pulp for glass interleaf, wherein the ratio of the above aluminum compounds is 25 / m ² or less.   The wood pulp for glass board interleaving paper of Claim 1 whose average particle diameter of the said aluminum-type compound is 20-300 micrometers.   The wood pulp for glass interleaf according to claim 1 or 2, wherein the glass plate is for a display.   The wood pulp for glass interleaf according to claim 3, wherein the display is a TFT liquid crystal display or an organic EL display.   A glass interleaf made of the wood pulp for glass interleaf according to any one of claims 1 to 4.   5. Use of wood pulp according to any of claims 1 to 4 for the production of glass interleaf. A paper for glass plates made from wood pulp,
Interleaf paper for glass plates having a particle size of 20 μm or more and at least one aluminum-based compound selected from the group consisting of aluminum hydroxide, aluminum oxide and aluminum silicate, present on the surface is 20 pieces / m ² or less .   The paper for glass plates of Claim 7 whose average particle diameter of the said aluminum-type compound is 20-300 micrometers.   9. The paper for glass plate according to claim 7, wherein the glass plate is for a display.   The paper for glass plate according to claim 9, wherein the display is a TFT liquid crystal display or an organic EL display.   A laminated body comprising the paper for a glass plate according to any one of claims 7 to 10 and a glass plate.   A method for protecting a glass sheet, comprising the step of inserting the glass sheet interleaf according to any one of claims 7 to 10 between a plurality of glass sheets.