TWI763813B - Glass plate-interleaving paper and manufacturing method thereof, laminate, and method for protecting glass plate - Google Patents

Abstract

The present invention relates to an interleaving paper for glass plates, the raw material of which is wood pulp, wherein the amount of silicone in the paper is 0.5 ppm or less, and the difference between the number on one surface of spots which include silicone and have a size of 30 μm or more and the number on the other surface of spots which include silicone and have a size of 30 μm or more is within 5 spots/1000m². The interleaving paper according to the present invention can solve problems derived from the difference in the conditions of the front and back surfaces of an interleaving paper for glass plates.

Description

Spacer paper for glass plate, method for producing the same, laminate, and method for protecting glass plate

The present invention relates to a paper for wrapping glass plates during storage and transportation by laminating a plurality of glass plates for flat panel displays such as liquid crystal displays, plasma displays, and organic electroluminescence (organic EL) displays, and sandwiching them in Paper between glass plates, and manufacture of such paper.

Generally speaking, in order to prevent the glass plates from contacting each other during the storage process of laminating and storing multiple glass plates for flat panel displays, and the distribution process of conveying by rails, etc. For the purpose of material contamination, paper called spacer paper is sandwiched between glass plates.

Compared with ordinary building window glass plates, vehicle window glass plates, etc., glass plates for flat panel displays are used for high-definition displays. Therefore, it is required that the glass surface be kept as clean as possible without impurities contained in the paper surface. , excellent flatness is required for high-speed responsiveness or widening of the viewing angle.

As a spacer paper used for such a purpose, as a spacer paper which can prevent breakage of a glass plate or surface damage, and as a spacer paper which does not contaminate the glass surface, several kinds have been proposed. For example, Patent Document 1 discloses a method of forming a fluorine coating film on the surface of a spacer paper. In addition, Patent Document 2 discloses a foam sheet made of polyethylene resin and a film made of polyethylene resin by bonding together. Spacer paper, Patent Document 3 discloses a spacer paper for glass, which is a paper composed of pulp containing 50% by mass or more of bleached chemical pulp, and contains a specific alkylene oxide adduct or a water-soluble polyether In addition, Patent Document 4 discloses a modified polysiloxane spacer paper for a glass plate, in which the amount of the resin component in the paper is specified, and a raw material considering the contamination of the glass surface is used.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2012-188785

[Patent Document 2] Japanese Patent Laid-Open No. 2010-242057

[Patent Document 3] Japanese Patent Laid-Open No. 2008-208478

[Patent Document 4] Japanese Patent Laid-Open No. 2006-44674

For example, in the production of a color filter substrate in an array step, which is one of the manufacturing steps of a TFT liquid crystal display, it is known that when the surface of the glass plate is contaminated, problems such as wire breakage will occur. The reason for this is that the color filter substrate is produced by forming thin films such as semiconductor films, ITO films (transparent conductive films), insulating films, and aluminum metal films on a glass plate by sputtering or vacuum evaporation. The presence of contaminants on the surface may cause disconnection in the circuit pattern formed by the thin film, or short circuit due to defects in the insulating film. In addition, in the production of the color filter substrate, the pattern produced by the photolithography method is formed on the glass plate, but in this step, if there are contaminants on the glass plate surface when the resist is coated, it will be Pinholes occur in the resist film after exposure or development, and as a result, disconnection or short circuit occurs. The same problem has also been confirmed in the manufacture of organic EL displays. Organic EL displays are produced by sputtering, vapor deposition, or printing to form thin films such as ITO anodes, organic light-emitting layers, and cathodes on glass substrates. Therefore, if there are foreign objects that obstruct the thin film on the surface of the glass substrate, the problem of no light emission occurs. .

Although it is difficult to identify the cause of the contamination of such a glass plate, it has been found that one of the causes is the fine foreign matter transferred from the surface of the spacer paper for the glass plate to the surface of the glass plate.

In addition, it was found that one of such foreign substances was a polysiloxane-based substance.

Furthermore, when a spacer paper for a glass plate is sandwiched between the glass plates, when there is a difference in the physical state of the front and back surfaces of the spacer paper, it may be considered that a specific surface of the spacer paper is brought into contact with the surface of the glass plate. situation of necessity. For example, a glass plate for flat panel displays has fine circuits formed on its surface, so even a small amount of foreign matter is especially avoided from adhering. If there is a foreign matter, the risk of the foreign matter being transferred to the surface of the glass plate becomes high, so it should be considered that the surface with more foreign matter is not in contact with the surface of the glass plate, but the surface with less foreign matter is in contact with the surface of the glass plate. The spacer paper is brought into contact with the surface of the glass plate. In this case, consider sandwiching 2 sheets of spacer paper between the glass plates, and make the surface with less foreign matter on the surface of each spacer paper facing the glass plate, but the amount of spacer paper used increases, and the spacer paper and Since the weight of the laminated body of the glass plate increases, it is not good in terms of handling.

The present invention makes it its subject to solve the above-mentioned problems caused by the difference in the state of the front and back of the spacer paper for a glass plate. In particular, this invention makes it a subject to provide the spacer paper for glass plates which can make either the front and back contact with a glass plate.

Therefore, as a result of diligent research, the present inventors found that by reducing the amount of the polysiloxane-containing foreign matter contained in the spacer paper for glass plates, the difference in the amount of the foreign matter on the front and back of the spacer paper is suppressed. The present invention is accomplished by providing a spacer paper for a glass plate that can contact either the front or the back of the spacer paper for a glass plate by suppressing the difference in the state of the front and back surfaces of the spacer paper for a glass plate.

A first aspect of the present invention is a spacer paper for glass plates, which uses wood pulp as a raw material, and has a polysiloxane content of 0.5 ppm or less, and a discontinuous region containing polysiloxane with a diameter of 30 μm or more on one surface. The difference between the number and the number of discontinuous regions containing polysiloxane with a diameter of 30 μm or more on the other surface is within 5 pieces/1000 m ² .

The number of the discontinuous regions on one surface of the spacer paper for a glass plate is preferably 15 pieces/1000 m ² or less.

It is preferable that content of the said polysiloxane in the said spacer paper for glass plates is 0.1 ppm or less.

The above-mentioned polysiloxane is preferably polysiloxane oil. Moreover, the above-mentioned polysiloxane oil is preferably dimethyl polysiloxane.

It is preferable that the thickness of the said spacer paper for glass plates is 20-200 micrometers.

The mean deviation (MMD) of the friction coefficient of the surface obtained by the KES method of the spacer paper for a glass plate is preferably 0.022 or less.

The above-mentioned glass plate is preferably for a display, more preferably a TFT liquid crystal display or an organic EL display.

A second aspect of the present invention relates to a manufacturing method, which is the manufacturing method of the above-mentioned spacer paper for a glass plate, which at least includes the following steps: a slurry preparation step of preparing a pulp of wood pulp; and a sheet formation step of The slurry is made into a sheet; the wet paper preparation step is to dehydrate the sheet to form wet paper; and the drying step is to dry the wet paper to obtain the spacer paper; and in the wet paper preparation step, from the sheet Dehydrate on both sides.

Preferably, the above-mentioned dehydration is performed by suction.

The difference between the dehydration ratio of the suction on one surface of the sheet and the dehydration ratio of the suction on the other surface is preferably 10% or less of the dehydration ratio of the suction on the other surface.

The above-mentioned manufacturing method preferably includes an additional suction step of further suctioning both sides of the spacer paper after the above-mentioned drying step.

Moreover, this invention also relates to the laminated body of the spacer paper for glass plates and the glass plate of the 1st aspect of this invention.

Moreover, this invention also relates to the protection method of a glass plate including the process of arranging the spacer paper for glass plates of the 1st aspect of this invention between glass plates.

The amount of polysiloxane contained in the spacer paper for glass plates of the present invention is small, the difference in the number of discontinuous regions containing polysiloxane on the front and back of the spacer paper is suppressed, and the positive and negative effects of the spacer paper for glass plates are suppressed. The difference in the existence state of the polysiloxane-containing foreign matter on the backside. Therefore, the spacer paper for a glass plate of the present invention can be brought into contact with the glass plate on either the front or the back. Thereby, the spacer paper for glass plates of this invention is excellent in workability|operativity.

In addition, the spacer paper for glass plates is initially rolled and shipped in a roll shape, but since the front surface and the back surface of the spacer paper are in contact with each other in this rolled state, for example, there are few polysiloxane-containing foreign substances in the front surface, and there are many foreign substances in the back surface. When there are many polysiloxane-containing foreign substances, even if the front side of the spacer paper is to be in contact with the surface of the glass plate, the polysiloxane-containing foreign substances on the back side of the spacer paper will be transferred to the front side in the coiled state. There is a risk that the cleanliness of the front will decrease.

However, even if the spacer paper for a glass plate of the present invention is wound into a roll shape, since the transfer of the polysiloxane-containing foreign matter from one surface to the other surface of the spacer paper is suppressed, there is no need to worry about the roll shape due to the roll. The resulting reduction in the cleanliness of the spacer paper surface.

Furthermore, since the spacer paper for a glass plate of the present invention contains a small amount of polysiloxane foreign matter, it is possible to effectively suppress or avoid the transfer of the fine foreign matter, which is a problem, from the spacer paper to the glass plate. In this way, by suppressing or avoiding the transfer of the problematic fine foreign matter to the glass plate, it is possible to prevent circuit disconnection of the color film or the like in the manufacturing process of the TFT liquid crystal display or the like.

A first aspect of the present invention is a spacer paper for glass plates, which uses wood pulp as a raw material, and has a polysiloxane content of 0.5 ppm or less, and a discontinuous region containing polysiloxane with a diameter of 30 μm or more on one surface. The difference between the number and the number of discontinuous regions containing polysiloxane with a diameter of 30 μm or more on the other surface is within 5 pieces/1000 m ² .

The wood pulps that can be used in the present invention are conifer bleached kraft pulp (NBKP), hardwood bleached kraft pulp (LBKP), softwood bleached sulfite pulp (NBSP), hardwood bleached sulfite pulp (LBSP), thermomechanical pulp ( TMP) and other wood pulps are used alone or in admixture. The wood pulp can be used as the main body, and modified pulp such as hemp, bamboo, straw, kenaf, mulberry, three-pole or cotton, cationized pulp, mercerized pulp and other modified pulp, rayon, vinylon, nylon, etc. , acrylic, polyester and other synthetic fibers or chemical fibers, or microfibrillated pulp are used alone or in combination. However, if the pulp contains a lot of resin components, it may cause adverse effects such as contamination of the surface of the glass plate with the resin components. Therefore, it is better to use chemical pulps with less resin components as much as possible, such as conifer bleached kraft pulp. Also, high-yield pulp such as groundwood pulp is not good because it contains a lot of resin components. In addition, when synthetic fibers or chemical fibers are mixed, the cutting property is improved, and the workability when the spacer paper is made into a lithographic plate is improved.

The form of the above-mentioned wood pulp is not particularly limited, and any form of flakes, blocks, or flakes can be adopted. Sheet pulp can be obtained using, for example, a pulp machine having four steps of a wire part, a press part, a drying part, and a final processing. Pulp fibers are made into paper using a Fourdrinier wire, a vacuum filter, or the like in the wire part, and dewatered using a roll press in the pressing part. In the drying section, drying is performed by a drum dryer or a hot air cushion dryer (flakt dryer), etc., and finally both ends of the sheet pulp are cut off and wound on a reel. This method is described in detail in the "Pulp Manufacturing Technology Series" or "Pulp Manufacturing Technology Complete" published by the Pulp Technology Association. book". In addition, lump-shaped pulp can be obtained by laminating|stacking the said sheet-shaped pulp, for example, and a sheet-shaped pulp can be obtained by pulverizing the said sheet-shaped pulp, for example.

The thickness of the above-mentioned sheet pulp is preferably 0.7 to 1.5 mm, more preferably 0.9 to 1.3 mm, and still more preferably 1.0 to 1.2 mm.

The basis weight of the above-mentioned sheet pulp is preferably 400-1300 g/m ² , more preferably 500-1200 g/m ^{2 , more preferably 500-1100 g/m 2 ,} further preferably 500-1000 g/m ² , and then More preferably, it is 700-1000 g/m ² .

In the spacer paper for a glass plate of the present invention, the content of polysiloxane contained in the spacer paper is limited to 0.5 ppm or less based on the weight of the spacer paper. The content of polysiloxane is preferably 0.4 ppm or less, more preferably 0.3 ppm or less, still more preferably 0.2 ppm or less, and particularly preferably 0.1 ppm or less.

On the other hand, in the spacer paper for glass plates of the present invention, polysiloxane may be present in an extremely small amount that does not become a problem, and therefore, the content of polysiloxane may not be 0. For example, the content of polysiloxane may also be 0.1 ppb.

The above polysiloxane content is based on the absolute dry mass of the spacer paper. In the present invention, "absolutely dry" means a state in which water is substantially not present in the object to be dried by drying.

The above polysiloxane content can be determined, for example, by subjecting the spacer paper to an extraction step in an organic solvent capable of extracting polysiloxane, and quantifying the amount of the extracted polysiloxane.

The shape of the discontinuous region containing polysiloxane in the present invention is arbitrary, such as various shapes such as circle, ellipse, square, etc., but preferably circle or ellipse. Specifically, the above-mentioned discontinuous regions may be dispersed in the form of dots or spots.

The discontinuous region containing polysiloxane in the present invention has a diameter of 30 μm or more. In the present invention, the "diameter" of the discontinuous region refers to the diameter of a circle of equal area (the diameter of a circle having an area equal to that of the discontinuous region). The diameter of the discontinuous region is preferably 25 μm or more, more preferably 20 μm or more, still more preferably 15 μm or more, still more preferably 10 μm or more, still more preferably 5 μm or more, More preferably, it is 1 μm or more, and even more preferably 0.5 μm or more. When the above-mentioned discontinuous region is circular, its diameter is referred to as "diameter". Also, when the discontinuous region is non-circular, the diameter of the circle of equal area (the diameter of a circle having an area equal to that of the discontinuous region) is preferably 25 μm or more, preferably 20 μm or more, more preferably 15 μm Above, more preferably 10 μm or more, still more preferably 5 μm or more, still more preferably 1 μm or more, and still more preferably 0.55 μm or more. The diameter and area of the above-mentioned discontinuous region can be measured, for example, by microscopy.

The diameter of the discontinuous region is preferably 10 mm or less, more preferably 5 mm or less, still more preferably 3 mm or less, still more preferably 1 mm or less, still more preferably 500 μm or less, still more preferably 100 μm or less, particularly preferably 50 μm the following. When the above-mentioned discontinuous region is circular, its diameter is preferably 10 mm or less, more preferably 5 mm or less, still more preferably 3 mm or less, still more preferably 1 mm or less, still more preferably 500 μm or less, still more preferably It is 100 micrometers or less, More preferably, it is 50 micrometers or less. When the discontinuous region is non-circular, the diameter of the circle of equal area is preferably 10 mm or less, preferably 5 mm or less, more preferably 3 mm or less, more preferably 1 mm or less, still more preferably 500 μm or less, and further More preferably, it is 100 μm or less, and even more preferably 50 μm or less.

Preferably, there is no discontinuous region containing polysiloxane with a diameter exceeding 10 mm on the surface of the spacer paper for a glass plate of the present invention.

In the spacer paper for glass plates of the present invention, the number of discontinuous regions containing polysiloxane with a diameter of 30 μm or more on one surface and the number of discontinuous regions containing polysiloxane with a diameter of 30 μm or more on the other surface The difference is within 5 pieces/1000m ² , preferably within 4 pieces/1000m ² , more preferably within 3 pieces/1000m ² , preferably within 2 pieces/1000m ² , still more preferably within 1 piece/1000m ² . That is, in the spacer paper for a glass plate of the present invention, the amount of the discontinuous region containing polysiloxane on one surface is preferably within the above-mentioned specific range compared with the amount of the discontinuous region on the other surface. will not change significantly. Here, the so-called "presence amount" refers to the number of the above-mentioned discontinuous regions containing polysiloxane per unit area of the surface of the spacer paper. A magnified observation was performed, and the number of discontinuous regions containing polysiloxane observed at the site was determined by averaging per unit area.

The discontinuous region containing polysiloxane on the surface of the spacer paper for glass plates of the first aspect of the present invention can be determined, for example, by coating the surface of the spacer paper with an affinity for polysiloxane and On the other hand, a colorant or developer that has no affinity with the spacer paper (typically hydrophobic) is measured for the colored area or color-developing area on the surface, or the surface of the spacer paper is coated with an affinity for the spacer paper. A colorant or developer having no affinity for polysiloxane on the other hand (typically a hydrophilic one) is used to measure the non-pigmented or non-pigmented areas on the surface.

The spacer paper for glass plates of the present invention contains a small amount of polysiloxane, and the variation in the presence of the discontinuous regions containing polysiloxane on the front and back of the spacer paper is suppressed, thereby suppressing the spacer for glass plates. The physical state of the front and back of the paper is different. Therefore, in the spacer paper for glass plates of the present invention, there is no situation in which the amount of the polysiloxane-containing foreign matter is greatly different between the front and back sides of the spacer paper. Therefore, the spacer paper for a glass plate of the present invention can be brought into contact with the glass plate on either the front or the back.

The foreign matter which becomes a problem in this invention contains polysiloxane. The discontinuous region containing polysiloxane on the surface of the spacer paper for a glass plate of the present invention corresponds to the foreign matter that is the problem of the present invention.

The type of polysiloxane contained in the discontinuous region containing polysiloxane on the surface of the spacer paper for a glass plate of the present invention is not particularly limited, and examples thereof include polysiloxane oil. Polysiloxane oil is hydrophobic, and its molecular structure can be any one of cyclic, linear and branched chains. The kinematic viscosity of polysiloxane oil at 25°C is usually in the range of 0.65~100,000mm ² /s, and can also be in the range of 0.65~10,000mm ² /s.

As a polysiloxane oil, a linear organopolysiloxane, a cyclic organopolysiloxane, and a branched organopolysiloxane are mentioned, for example.

Examples of linear organopolysiloxanes, cyclic organopolysiloxanes, and branched organopolysiloxanes include organic compounds represented by the following general formulae (1), (2) and (3). Polysiloxane.

R ¹ ₃ SiO-(R ¹ ₂ SiO) _a -SiR ¹ ₃ (1)

R ¹ _(4-c) Si(OSiR ¹ ₃ ) _c (3)

(in the formula, R ¹ is independently a hydrogen atom, a hydroxyl group, or a group selected from the group represented by a substituted or unsubstituted monovalent hydrocarbon group and an alkoxy group, a is an integer from 0 to 1000, and b is 3 An integer of ~100, c is an integer of 1 to 4, preferably an integer of 2 to 4)

The substituted or unsubstituted monovalent hydrocarbon group is typically: substituted or unsubstituted carbon number 1-30, preferably carbon number 1-10, more preferably carbon number 1-4 saturated with a valence Hydrocarbon group; substituted or unsubstituted carbon number 2-30, preferably carbon number 2-10, more preferably a valent unsaturated hydrocarbon group with carbon number 2-6; carbon number 6-30, more Preferably, it is a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms.

Examples of the monovalent saturated hydrocarbon group having 1 to 30 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl Alkyl, hexyl, heptyl, octyl, nonyl, decyl and other linear or branched alkyl groups, and cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl and other cycloalkyl groups.

Examples of the monovalent unsaturated hydrocarbon group having 2 to 30 carbon atoms include vinyl, 1-propenyl, allyl, isopropenyl, 1-butenyl, 2-butenyl, pentenyl, Linear or branched alkenyl such as hexenyl; cycloalkenyl such as cyclopentenyl, cyclohexenyl; cycloalkenyl such as cyclopentenylethyl, cyclohexenylethyl, cyclohexenylpropyl alkenyl alkyl; and alkynyl groups such as ethynyl and propargyl.

Examples of the monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms include aryl groups such as a phenyl group, a tolyl group, a xylyl group, and a 2,4,6-trimethylphenyl group. Preferred is phenyl. Furthermore, in this manual, the The aromatic hydrocarbon group includes, in addition to a group composed of only an aromatic hydrocarbon, a group in which an aromatic hydrocarbon and an aliphatic saturated hydrocarbon are compounded. Examples of groups in which aromatic hydrocarbons and saturated hydrocarbons are compounded include aralkyl groups such as benzyl and phenethyl.

The hydrogen atom on the above-mentioned monovalent hydrocarbon group may be substituted by one or more substituents, for example, the substituents are selected from halogen atoms (fluorine atom, chlorine atom, bromine atom and iodine atom), hydroxyl group, methanol group, epoxy group, A group consisting of organic groups such as glycidyl, acyl, carboxyl, amine, methacryloyl, mercapto, acylamino, oxyalkylene, etc. Specifically, 3,3,3-trichloropropyl, 3-chloropropyl, 3-hydroxypropyl, 3-(2-hydroxyethoxy)propyl, 3-carboxypropyl, 10 -Carboxydecyl, 3-isocyanatopropyl, etc.

As an alkoxy group, a methoxy group, an ethoxy group, a propoxy group, etc. are mentioned, Preferably it is a methoxy group or an ethoxy group, More preferably, it is a methoxy group.

More specifically, as a linear organopolysiloxane, there can be exemplified: trimethylsiloxy-terminated dimethylpolysiloxane at both ends of the molecular chain (low viscosity such as 2mPa·s or 6mPa·s ~100 Dimethyl polysiloxane with high viscosity such as 10,000 mPa·s), organohydrogenated polysiloxane, trimethylsiloxy-terminated methylphenyl polysiloxane at both ends of the molecular chain, and trimethyl at both ends of the molecular chain Siloxy-terminated dimethylsiloxane-methylphenylsiloxane copolymer, trimethylsiloxy-terminated diphenyl polysiloxane at both ends of the molecular chain, and trimethyl at both ends of the molecular chain Siloxy-terminated dimethylsiloxane-diphenylsiloxane copolymer, trimethylpentaphenyltrisiloxane, phenyl(trimethylsiloxy)siloxane, both ends of molecular chain Trimethylsiloxy-terminated methylalkyl polysiloxane, trimethylsiloxy-terminated dimethylpolysiloxane-methylalkylsiloxane copolymer at both ends of the molecular chain, two molecular chains Terminated trimethylsiloxy-terminated dimethylsiloxane-methyl(3,3,3-trifluoropropyl)siloxane copolymer, α,ω-dihydroxypolydimethylsiloxane, α,ω-diethoxypolydimethylsiloxane, 1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane, 1,1,1,3 ,5,5,5-heptamethyl-3-dodecyltrisiloxane, 1,1,1,3,5,5,5-heptamethyl-3-hexadecyltrisiloxane , tris(trimethylsiloxy)methylsilane, tris(trimethylsiloxy)alkylsilane, tetrakis(trimethylsiloxy)silane, tetramethyl-1,3- Dihydroxydisiloxane, Octamethyl-1,7-dihydroxytetrasiloxane, Hexamethyl-1,5-diethoxytrisiloxane, Hexamethyldisiloxane, Octamethyl Trisiloxane, advanced alkoxy-modified polysiloxane, higher fatty acid-modified polysiloxane, dimethylsiloxane, etc.

As cyclic organopolysiloxane, hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclopentasiloxane (D5) can be exemplified. Methylcyclohexasiloxane (D6), 1,1-diethylhexamethylcyclotetrasiloxane, phenylheptamethylcyclotetrasiloxane, 1,1-diphenylhexamethylcyclotetrasiloxane Siloxane, 1,3,5,7-Tetravinyltetramethylcyclotetrasiloxane, 1,3,5,7-Tetramethylcyclotetrasiloxane, 1,3,5,7-Tetra Cyclohexyltetramethylcyclotetrasiloxane, tris(3,3,3-trifluoropropyl)trimethylcyclotrisiloxane, 1,3,5,7-tetrakis(3-methacryloyloxy) propyl) tetramethylcyclotetrasiloxane, 1,3,5,7-tetrakis(3-propenyloxypropyl)tetramethylcyclotetrasiloxane, 1,3,5,7-tetrakis (3-Carboxypropyl)tetramethylcyclotetrasiloxane, 1,3,5,7-tetrakis(3-vinyloxypropyl)tetramethylcyclotetrasiloxane, 1,3,5,7 -Tetrakis(p-vinylphenyl)tetramethylcyclotetrasiloxane, 1,3,5,7-tetra[3-(p-vinylphenyl)propyl]tetramethylcyclotetrasiloxane, 1 ,3,5,7-tetrakis(N-acryloyl-N-methyl-3-aminopropyl)tetramethylcyclotetrasiloxane, 1,3,5,7-tetrakis(N,N- Bis(lauryl)-3-aminopropyl)tetramethylcyclotetrasiloxane and the like.

Examples of branched organopolysiloxanes include methyltris(trimethylsiloxy)silane, ethyltris(trimethylsiloxy)silane, and propyltris(trimethylsiloxy)silane. Silane, tetrakis(trimethylsiloxy) silane, phenyl tris(trimethylsiloxy) silane, etc.

As the polysiloxane oil in the present invention, preferably dimethyl polysiloxane, diethyl polysiloxane, methylphenyl polysiloxane, polydimethyl-polydiphenylsiloxane Copolymer, polymethyl-3,3,3-trifluoropropylsiloxane, etc. The polysiloxane in the present invention is typically dimethyl polysiloxane.

The polysiloxane oil in the present invention can also be modified polysiloxane oil. Examples of the modified polysiloxane oil include polyoxyalkylene modified polysiloxane oil.

Polyoxyalkylene modified polysiloxane oil is a polysiloxane oil with a polyoxyalkylene group bonded through a silicon-carbon bond in the molecule, preferably at room temperature, specifically at 25°C to show water soluble, and more Preferably non-ionic ones.

Specifically, polyoxyalkylene modified polysiloxane oil is, for example, a copolymer of polysiloxane oil composed of linear or branched chain silicone and polyoxyalkylene, and there are various polyoxyalkylenes. The alkyl-modified polysiloxane oil is particularly preferably represented by the following formula (4).

R ² ₃ SiO-(R ¹ ₂ SiO) _d -(R ¹ ASiO) _e -SiR ² ₃ (4)

(wherein, R ¹ is independently the same as above, R ² is independently R ¹ or A, A is independently a group represented by R ³ G, R ³ is a substituted or unsubstituted divalent hydrocarbon group, G Represents a polyoxyalkylene containing at least one type of alkylene oxide having 2 to 5 carbon atoms, such as ethylene oxide and propylene oxide, d represents an integer from 1 to 500, and e represents an integer from 1 to 50)

Examples of the substituted or unsubstituted divalent hydrocarbon group include linear or branched divalent hydrocarbon groups having 1 to 30 carbon atoms, and specific examples thereof include methylene, dimethylene, Linear or branched alkylene with 1 to 30 carbon atoms such as trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, and octamethylene; vinylidene Alkenyl, propynyl, butenyl, hexenyl, octenyl and other alkenyl groups with 2 to 30 carbon atoms; phenylene, biphenylene and other alkene groups with carbon atoms of 6 to 30 alkylene groups; alkylene groups with 7 to 30 carbon atoms such as dimethylene phenylene groups; and hydrogen atoms bonded to the carbon atoms of these groups are at least partially substituted with halogen atoms such as fluorine, hydroxyl groups, Or organic groups such as methyl alcohol group, epoxy group, glycidyl group, acyl group, carboxyl group, amino group, methacryloyl group, mercapto group, amide group, oxyalkylene group, etc. The divalent hydrocarbon group is preferably an alkylene group having 1 to 30 carbon atoms, preferably an alkylene group having 1 to 6 carbon atoms, and more preferably an alkylene group having 3 to 5 carbon atoms.

For example, as a specific example of a polyoxyalkylene-modified polysiloxane oil, the following can be mentioned.

(In the formula, x is 20~160, y is 1~25, the value of x/y is 50~2, A is for example -(CH ₂ ) ₃ O-(CH ₂ CH ₂ O) _m -(CH ₂ CH ₂ CH ₂ O) _n -R ⁴ , m is 7~40, n is 0~40, the value of m+n is at least 1, which can be either graft-polymerized or random-polymerized, R ⁴ Represents a hydrogen atom or the above-mentioned substituted or unsubstituted monovalent hydrocarbon group; preferably, m is 7~30, and n is 0~30)

Moreover, as a modified polysiloxane oil, aminoalkyl modified polysiloxane oil is mentioned, for example.

Aminoalkyl-modified polysiloxane oil is a polysiloxane oil with aminoalkyl groups bonded through a silicon-carbon bond in the molecule, preferably at room temperature, specifically at 25°C, showing 10~ The viscosity of 100000cs.

Examples of the above-mentioned aminoalkyl polysiloxane oil include those in the above formula (4) where G is substituted with the formula: -(NR ⁴ CH ₂ CH ₂ ) _z NR ⁴ ₂ (wherein R ⁴ is each independently as above As mentioned above, z is the number of 0≦z≦4).

The thickness of the spacer paper for a glass plate of the present invention is preferably 20 to 200 μm, more preferably 30 to 150 μm, and still more preferably 40 to 200 μm. In this way, by making the spacer paper relatively thin, the difference in the physical state of the front and back of the spacer paper can be further suppressed.

The basis weight of the spacer paper for a glass plate of the present invention is preferably 20 to 80 g/m ² , more preferably 25 to 70 g/m ² , and still more preferably 30 to 60 g/m ² .

Regarding the spacer paper for a glass plate of the present invention, the mean deviation (MMD) of the friction coefficient of the surface obtained by the KES method is preferably 0.022 or less, more preferably 0.020 or less, more preferably 0.019 or less, and still more preferably 0.018 Below, more preferably, it is 0.017 or less. MMD is a friction tester (KES-SE manufactured by Kato Tech Co., Ltd.), while a 10mm square friction element composed of a bundle of high-tensile steel wires with a diameter of 0.5mm is contacted with a contact pressure of 50g/cm ² . The average deviation of the coefficient of friction measured when the surface of the paper fixed with a tension of 20g/cm is contacted, and the sample is moved 2cm in the same direction as the direction of applying the tension at a speed of 0.1cm/sec. When the MMD is large, it means that the friction coefficient of the paper surface greatly varies depending on the position of the paper surface, and microscopically, it means that there are many fine irregularities on the surfaces of the paper. By providing the fine unevenness on the surface of the spacer paper in this way, the friction coefficient between the surface of the glass plate and the surface of the spacer paper becomes small, and the removal operation when the spacer paper is removed from the surface of the glass plate becomes easy. If the MMD exceeds 0.022, the microscopic irregularities on the surfaces of the papers will increase, and the involvement of the papers will increase, which is not preferable. MMD is, for example, preferably 0.001 to 0.022, more preferably 0.002 to 0.020, and still more preferably 0.004 to 0.019.

The spacer paper for a glass plate of the present invention may also contain short fibers having a fiber length of 200 μm or less, but the short fibers may attract foreign matter, so the content of the short fibers is preferably limited.

The content of short fibers having a fiber length of 200 μm or less in the spacer paper for glass plates of the present invention is preferably 10.5% by weight or less, more preferably 10.0% by weight or less, and still more preferably 9.5% by weight relative to the absolute dry mass of the spacer paper. % by weight or less, particularly preferably 9.0% by weight or less. Here, the "fiber length" does not mean the average fiber length. Therefore, all the short fibers having a fiber length of 200 μm or less have a fiber length of 200 μm or less. In other words, the maximum fiber length of the short fibers is 200 μm or less. Here, the term "fiber length" refers to the length of the fiber when the fiber is stretched straight.

The average fiber diameter of the short fibers is preferably 10 μm to 50 μm, more preferably 12 μm to 40 μm, and still more preferably 15 μm to 30 μm. Furthermore, the "average fiber diameter" here refers to the magnified observation of a plurality of parts on the surface of the spacer paper for glass plates by an electron microscope, and a specific number of fibers are randomly selected from each electron microscope image, and the selected fibers are measured. the diameter of the fibers and average the obtained average fiber diameter. The number of fibers to be screened is 100 or more, preferably 150 or more, more preferably 200 or more, and still more preferably 300 or more.

The amount of the above-mentioned short fibers on the surface of the spacer paper for glass plates of the present invention is preferably 300 to 850 fibers/cm ² , more preferably 330 to 800 fibers/cm ² , more preferably 350 to 750 fibers/cm 2 . cm ² . If the short fibers are present in relatively small amounts, the amount of foreign matter drawn by the short fibers can be reduced.

In the spacer paper for glass plates of the present invention, the difference between the amount of the above-mentioned short fibers on one surface and the amount of the above-mentioned short fibers on the other surface is preferably 15% of the amount of the above-mentioned short fibers on the other surface. Below, it is more preferable that it is 12% or less, and it is still more preferable that it is 10% or less. That is, in the spacer paper for glass plates of the present invention, it is preferable that the amount of short fibers on one surface is not significantly greater than the amount of short fibers present on the other surface to fall within the above-mentioned specific range. change. Here, the so-called "presence amount" refers to the number of the above-mentioned short fibers per unit area on the surface of the spacer paper, and for example, it can be observed by magnifying a plurality of parts of the surface of the spacer paper for glass plates with an electron microscope, The number of short fibers observed at the site was determined by averaging per unit area. In addition, it can also be determined by the number per unit area of short fibers of 200 μm or less obtained from the fibers that fell with the surface of the spacer paper facing downward and rubbed against a specific area with a sheet or the like. Furthermore, it can also be determined by dividing the spacer paper into two equal parts in the center of the thickness direction to obtain two very thin sheets, pulping each paper, and measuring the number of short fibers of 200 μm or less in the slurry. Alternatively, as another method, the amount of the short fibers can be determined by sufficiently washing the surface of a specific area of the spacer paper for glass plates with water, and supplying the fallen fibers to a fiber length measuring machine.

The spacer paper for glass plates of the present invention may also contain talc, but since the surface of talc is relatively lipophilic and has the property of adsorbing polysiloxane to form a complex, it is preferable to suppress the content of talc. Furthermore, the form of the composite of talc powder and polysiloxane is not particularly limited, and at least a part of talc powder may be coated with polysiloxane, or the polysiloxane may penetrate into at least a part of talc powder.

In the spacer paper for glass plates of the present invention, the presence ratio of talc powder on one surface is preferably 3 pieces/100m ² or less, more preferably 2 pieces/100m ² or less, and still more preferably 1 piece/100m ² or less, More preferably, it is 0.8 pieces/100m ² or less, still more preferably 0.6 pieces/100m ^{2 or less, still more preferably 0.4 pieces/100m 2 or less, and still more preferably 0.2 pieces/100m 2 or less} .

In the spacer paper for glass plates of the present invention, the difference between the presence ratio of talc powder on one surface and the presence ratio of talc powder on the other surface is preferably within 5 pieces/100m ² , more preferably 4 pieces/100m Within ² , more preferably within 3/100m ² , more preferably within 2/100m ² , still more preferably within 1/100m ² . That is, in the spacer paper for glass plates of the present invention, it is preferable that the ratio of the talc powder on one surface and the ratio of the talc powder on the other surface do not change significantly to the extent that it falls within the above-mentioned specific range. . Here, the so-called "presence ratio" refers to the number of talc powder per unit area of the surface of the spacer paper, for example, it can be observed by magnifying a plurality of parts of the surface of the spacer paper for glass plates by using an electron microscope, and the The amount of talc observed at the site was averaged and determined. Alternatively, as another method, the presence ratio of the talc powder can be determined by sufficiently washing the surface of a specific area of the spacer paper for glass plates with an acidic solution such as water or concentrated sulfuric acid, and counting the detached talc powder.

The talc in the present invention is not particularly limited. Talc is called "hydrous magnesium silicate", and its chemical formula can be 4SiO ₂ . 3MgO. represented by H ₂ O. The chemical composition is slightly different depending on the place of production, but the theoretical value is the weight ratio of SiO ₂ 64.4%, MgO 31.8%, and ignition loss (moisture) 4.7%. Talc is also known as talc.

The average particle size of the talc powder is not particularly limited, but is preferably 1 to 10 μm, more preferably 1 to 8 μm, still more preferably 1 to 6 μm, and particularly preferably 1 to 4 μm. The above-mentioned average particle diameter may be a volume average particle diameter, and can be measured by, for example, a laser diffraction or scattering method.

The surface area of the talc powder is not particularly limited, but the specific surface area obtained by the BET method is preferably 1 m ² /g or more, more preferably 10 m ² /g or more, and still more preferably 20 m ² /g or more.

The density of the talc powder is not particularly limited, but the apparent density based on JIS K5101 is preferably 1 g/ml or less, more preferably 0.8 g/ml or less, still more preferably 0.6 g/ml or less, and still more preferably 0.4 g/ml ml or less, more preferably 0.2 g/ml or less.

The average particle diameter of the composite form of the talc powder and the hydrophobic substance is preferably 30 μm or more, more preferably 40 μm or more, and still more preferably 50 μm or more.

The spacer paper for glass plates of the present invention can be produced based on a usual method such as a papermaking method.

A second aspect of the present invention is a manufacturing method, which is a manufacturing method of a spacer paper for glass plates, which includes at least the following steps: a slurry preparation step of preparing a pulp of wood pulp; a sheet formation step of converting the slurry In the wet paper preparation step, the sheet is dehydrated to form wet paper; in the drying step, the wet paper is dried to obtain the spacer paper; and in the wet paper preparation step, the sheet-like slurry is obtained Dehydrate on both sides.

In the above-mentioned slurry preparation step, the pulp of wood pulp can be prepared by a conventionally known method. For example, in the above-mentioned slurry preparation step, the cellulose fibers constituting the wood pulp are dissociated to form an aqueous suspension, and the slurry is prepared.

In addition, adhesives, antifungal agents, antifoaming agents, fillers, wet paper strength enhancers, dry paper strength enhancers, sizing agents, coloring agents may be added to the above-mentioned slurry as necessary within the range that does not impair the performance of the present invention. agents, fixatives, yield improvers, viscosity control agents, etc. Furthermore, when adding these chemicals, it is better to be careful not to mix in insects or dirt.

Generally speaking, polysiloxane is contained in wood pulp and spacer paper in many cases. The reason for this is that, in the manufacturing process of wood pulp and spacer paper, especially in the cleaning step, as a defoaming agent to prevent the reduction of cleaning ability caused by the generation of air bubbles, polysiloxane-based defoaming agents are often used. agent, the polysiloxane derived from the polysiloxane-based defoamer remains in the pulp and spacer paper. For example, polysiloxane-based defoamer is produced by mixing modified polysiloxane, surfactant, etc. into a mixture of polysiloxane oil and hydrophobic silica.

In the second aspect of the present invention, when an antifoaming agent is used in order to reduce the content of polysiloxane contained in the spacer paper for glass plates to 0.5 ppm or less, a non-polysiloxane-based defoaming agent can be used. agent as a defoamer. Furthermore, it is preferable to use the wood pulp obtained by using a non-silicon-based antifoaming agent.

Examples of non-silicone-based antifoaming agents include mineral oil-based antifoaming agents, higher alcohol-based antifoaming agents, fatty acid-based antifoaming agents, fatty acid ester-based antifoaming agents, amide-based antifoaming agents, Amine-based defoaming Antifoaming agent, phosphate ester defoamer, metal soap defoamer, sulfonate defoamer, polyether defoamer and vegetable oil defoamer.

The mineral oil-based antifoaming agent includes, for example, mineral oil such as hydrocarbon oil, mineral wax, and the like.

The higher alcohol-based antifoaming agent includes, for example, octanol, cetyl alcohol, and the like.

The fatty acid-based antifoaming agent includes, for example, palmitic acid, oleic acid, stearic acid, and the like.

The fatty acid ester-based antifoaming agent includes, for example, isoamyl stearate, glycerol monoricinoleate, sorbitan monolaurate, sorbitan trioleate, and the like.

The amide-based antifoaming agent includes, for example, acrylate polyamine and the like.

The amine-based antifoaming agent includes, for example, diallylamine and the like.

The phosphate-based antifoaming agent includes, for example, tributyl phosphate, sodium octyl phosphate, and the like.

The metal soap-based antifoaming agent contains, for example, aluminum stearate, calcium stearate, potassium oleate, and the like.

The sulfonate-based antifoaming agent includes, for example, sodium lauryl sulfonate, sodium dodecyl sulfonate, and the like.

The polyether-based antifoaming agents include, for example, polyoxyalkylenes such as (poly)oxyethylene (poly)oxypropylene adducts; diethylene glycol heptyl ether, polyoxyethylene oleyl ether, polyoxypropylene butyl ether, polyoxypropylene Oxyethylene polyoxypropylene 2-ethylhexyl ether, oxyethylene oxypropylene adducts of higher alcohols having 8 or more carbon atoms or secondary alcohols having 12 to 14 carbon atoms, etc. (poly)oxyalkylene alkyl ethers (poly) oxyalkylene (alkyl) aryl ethers such as polyoxypropylene phenyl ether, polyoxyethylene nonyl phenyl ether, etc.; make alkylene oxide and 2,4,7,9-tetramethyl-5 -Addition of acetylenic alcohols such as decyne-4,7-diol, 2,5-dimethyl-3-hexyn-2,5-diol, 3-methyl-1-butyn-3-ol Polymerized acetylene ethers; (poly)oxyalkylene fatty acid esters such as diethylene glycol oleate, diethylene glycol laurate, ethylene glycol distearate; polyoxyethylene sorbitan Monolaurate, polyoxyethylene sorbitan trioleate and other (poly)oxyalkylene sorbitan fatty acid esters; polyoxypropylene methyl ether sodium sulfate, polyoxyethylene lauryl phenol ether sodium sulfate, etc. (Poly) oxyalkylene alkyl (aryl) ether sulfates; (poly) oxyethylene stearyl phosphate and other (poly) oxyalkylene alkyl phosphates; polyoxyethylene laurylamine, etc. ( Poly) oxyalkylene alkylamines; polyoxyalkylene amides, etc.

Vegetable oil-based antifoaming agents include, for example, soybean oil, corn oil, coconut oil, linseed oil, Vegetable oils such as rapeseed oil, cottonseed oil, sesame oil, castor oil, etc.

In addition, the non-polysiloxane-based antifoaming agent may contain inorganic particles such as hydrophobic silica. As the hydrophobic silica, it is preferable to use a hydrophobized silica by substituting a silanol group of the hydrophilic silica with an alkyl group such as a methyl group.

The non-polysiloxane-based defoamer may also contain surfactants and the like as required. Therefore, the non-polysiloxane-based defoamer can also be an emulsion type.

In preparing the above-mentioned pulp, if the pulp is beaten, the effect of increasing the strength between the paper layers can be expected. However, if the fine fibers are increased by beating, there is a possibility that foreign matter will be drawn, or paper powder will be generated during use as spacer paper, so it is not suitable to increase the beating degree more than necessary. The preferred beating degree in the present invention is 300-650 mlc.s.f..

In the sheet formation step of making the above slurry into a sheet shape, sheet formation can be performed by a conventionally known method. For example, the above-mentioned slurry can be sprayed onto a flat wire (such as a Fourdrinier wire paper machine), or a wire wound on a cylindrical cylinder is used to extract a sheet from the pulp (such as a rotary wire paper machine). Get slices.

In the second aspect of the present invention, in the wet paper preparation step of dewatering the sheet to form wet paper, dehydration is performed from both sides of the sheet. Thereby, the polysiloxane-containing foreign matter contained in the above-mentioned sheet is effectively removed from both sides of the sheet. Furthermore, the number of discontinuous regions containing polysiloxane with a diameter of 30 μm or more on one surface of the spacer paper for a glass plate obtained by the second aspect of the present invention and the diameter of 30 μm or more on the other surface can be calculated. The difference in the number of discontinuous regions containing polysiloxane was set to within 5 pieces/1000 m ² .

The above-mentioned dehydration method is optional, and a conventionally known method can be used. For example, dehydration can be carried out by pressing the above-mentioned sheet with a roller. However, in order to effectively remove the polysiloxane-containing foreign matter, the above-mentioned dehydration is preferably performed by suction.

For example, in the step of dewatering from both sides of the sheet, in the state that the sheet extending in the horizontal direction is sandwiched from top to bottom by a net, dewatering can be performed by suction in the up and down direction by a suction device, but due to the influence of gravity There is a difference between the suction force in the upward direction and the suction force in the downward direction. Compared with the surface of the sheet on the side to be sucked, there is a possibility that more polysiloxane-containing foreign matter will remain on the surface of the sheet on the side to be suctioned in the upward direction, so it is better to use a mesh to sandwich the sheet that extends in the vertical direction. And suction in the left and right direction to dehydrate. In this case, the moving direction of the wet paper is preferably maintained within a vertical direction or a range within 30° inclined from the vertical direction.

The difference between the dehydration ratio of the suction on one surface of the sheet and the dehydration ratio of the suction on the other surface is preferably 10% or less of the dehydration ratio of the suction on the other surface. That is, in the manufacturing method of the spacer paper for glass plates of this invention, it is preferable to perform suction from both surfaces of a sheet|seat with substantially the same suction force.

The above-mentioned sheet forming step and wet paper preparation step may be performed individually using different apparatuses, or may be performed continuously or partially overlapped in the same apparatus. For example, in the wire part of a paper machine, while the slurry is loaded on a wire to form a sheet, it can be dewatered to form a wet paper.

In the above-mentioned drying step, the above-mentioned spacer paper can be obtained by drying the wet paper by a conventionally known method using a drying roll or the like.

In order to further remove the polysiloxane-containing foreign matter that may remain on the surface of the spacer paper, the manufacturing method of the spacer paper for a glass plate of the present invention preferably includes an additional suction step of further suctioning both sides of the spacer paper after the above drying step .

Furthermore, processing such as calender processing, super calender processing, soft calender processing, and embossing may be performed during and/or after papermaking of the spacer paper for glass plates. Surface properties and thickness can be adjusted by processing.

By the manufacturing method of the 2nd aspect of this invention, the spacer paper for glass plates of the 1st aspect of this invention can be manufactured efficiently.

Whether the spacer paper obtained by the manufacturing method of the second aspect of the present invention matches the characteristics of the spacer paper for glass plates of the first aspect of the present invention can be determined, for example, by using the same batch of A part of the spacer paper obtained by the production method of wood pulp is used as a sample, and an extraction step is performed in an organic solvent capable of extracting polysiloxane, and the amount of the extracted polysiloxane is quantified. The paper is coated on both sides with a colorant or developer having an affinity for polysiloxane and, on the other hand, no affinity for the spacer paper (typically one that is hydrophobic), and determining the colored or developed area on each surface, or A colorant or developer having an affinity with the spacer paper and on the other hand having no affinity with polysiloxane was coated on both sides of the spacer paper, and the non-colored area or the non-colored area on each surface was measured. In addition, the content of polysiloxane in the above-mentioned samples is 0.5 ppm or less, and the number of discontinuous regions containing polysiloxane with a diameter of 30 μm or more on one surface and the number of polysiloxane containing polysiloxane with a diameter of 30 μm or more on the other surface When the difference in the number of discontinuous regions is within 5 pieces/1000m ² , all the spacer papers prepared from the above-mentioned batch of wood pulp can be regarded as the first aspect of the present invention as the spacer paper for glass plates.

In addition, generally speaking, talc is contained in wood pulp and spacer paper in many cases. The reason for this is that in the production process of wood pulp and spacer paper, talc is often used as a pitch control agent. Furthermore, talc is used not only as a resin control agent, but also as a filler and a pigment for paper coating, and has the effect of improving the whiteness of the paper and improving the printing characteristics.

When the presence ratio of talc powder on one surface of the spacer paper obtained by the second aspect of the present invention is 3 pieces/100 m ² or less, non-talc-based resin control agents, fillers, and pigments can be used. Wait.

In addition, in the wet paper preparation step of dehydrating the sheet in the second aspect of the present invention to form wet paper, dehydration from both sides of the sheet can effectively remove the content contained in the sheet from both sides of the sheet. of talcum powder. Therefore, the difference between the existence ratio of talc powder on one surface and the existence ratio of talc powder on the other surface of the spacer paper for glass plates obtained by the second aspect of the present invention may be set to 5 pieces/100 m ² or less.

The spacer paper for glass plates of the present invention is used by being inserted between glass plates. For example, the above-mentioned spacer paper for glass plates is typically inserted one by one between a plurality of glass plates, and as a whole, it becomes a laminated body, and this laminated body becomes the object of storage and conveyance. Moreover, the spacer paper for glass plates of the present invention can also be used for packaging glass A single glass plate or the above-mentioned laminate. Therefore, this invention has the aspect of the protection method of the glass plate including the step of disposing (especially inserting) the spacer paper for a glass plate between glass plates.

Although it does not specifically limit as a glass plate, Preferably it is a glass plate for flat-panel displays, such as a plasma display panel, a liquid crystal display panel (especially a TFT liquid crystal display panel), and an organic electroluminescent display panel. Fine electrodes, partitions, etc. are formed on the surface of the glass plate for a flat panel display. However, by using the spacer paper for a glass plate of the present invention, the transfer of the microscopic foreign matter to the glass plate, which is a problem, is suppressed or avoided. Forming fine electrodes, partition walls, etc. on the surface of the board can also suppress or avoid the defects caused by the foreign matter, and as a result, the defects of the display can be suppressed or avoided.

In particular, with the enlargement of the display, the size and weight of the glass plate for a flat panel display increase, and the spacer paper for a glass plate of the present invention can well protect the surface of such a large or heavy glass plate. In particular, the spacer paper for a glass plate of the present invention has very little content of the fine polysiloxane-containing foreign matter, so even if it is pressed by a heavy glass plate, the transfer of the foreign matter to the glass plate can be suppressed or avoided. Therefore, the spacer paper for a glass plate of the present invention can be preferably used for a glass plate for a flat panel display, which particularly requires surface cleanliness.

[Example]

Hereinafter, the present invention will be described in more detail using Examples and Comparative Examples, but the scope of the present invention is not limited to the Examples.

[content of polysiloxane]

The glass plate was cut into about 1 cm square with spacer paper, and Soxhlet extraction was performed using hexane for about 3 and a half hours. The obtained extract was condensed with a rotary evaporator, dissolved again in 1 mL of deuterochloroform, and subjected to ¹ H-NMR measurement. In this quantification, in order to prepare a calibration curve, a deuterochloroform solution of polydimethylsiloxane was used as a standard, and the quantification was performed by an absolute calibration method. In addition, the NMR apparatus used was AVANCE500 (manufactured by Bruker Biospin).

[Number of discontinuous regions containing polysiloxane]

A 1 wt% aqueous solution of direct dye "Levacell fast black G" (Blankophor Gmbh & Co. KG) was applied to the surface of the spacer paper for glass plates, and as a result, the non-colored discontinuous regions produced were counted with a diameter of more than 30 μm , determine its existence (number per 1000m2 ⁾ .

[Test method for transfer to glass plate (conveyance test)]

Apply foamed urethane to the glass mounting surface of the L-shaped pedestal made of aluminum with an angle of 75 degrees, and the mounting surface for mounting the glass plate in the vertical direction and the rear end facing the self-mounting surface The size of the backrest extending vertically is 680mm x 880mm x 0.7mm. Between each glass plate, 120 glass plates are inserted with spacer paper for glass plates, and the backrest is erected so as to be parallel to the backrest. A belt in the shape of a belt is erected over the entire circumference from the rear end to the backrest to fix the glass plate. The pedestal set as described above is covered with a packing material to prevent the entry of dust, dirt, etc. from the outside. After that, a transport test on the track is carried out. Conveying test conditions were carried out at a conveying distance of 1000 km (stored in an environment of 40°C x 95% RH for 5 days in the middle of conveying).

[Example 1]

In a manufacturing apparatus for softwood bleached kraft pulp consisting of a cooking step, a washing step, an oxygen delignification reaction step, and a multi-stage bleaching step using chlorine dioxide and hydrogen peroxide, after the cooking step, it is used for After removing the antifoaming agent of the cleaning liquid of the cylindrical washing machine after the knot, add an appropriate amount of the mineral oil-based antifoaming agent "Pronal A5044" (manufactured by Toho Chemical Co., Ltd.) as a non-silicone-based antifoaming agent continuously. . In addition, as the defoaming agent added to the washing press in the step of pressure washing, an appropriate amount of "Pronal A5044" was similarly added. In addition, in the washing step, washing with a solvent in which toluene and methanol were mixed, followed by filtration, was repeated 5 times. As described above, softwood bleached kraft pulp using a non-silicone-based defoamer is obtained in the production step. 100 parts by mass of this softwood bleached kraft pulp was prepared, and 0.2 part by mass of polypropylene amide as a paper strength enhancer was added to the pulp having a beating degree of 550 mlc.sf by dissociating it. (trade name: Polystron 1250, manufactured by Arakawa Chemical Industry Co., Ltd.), and adjusted to a pulp slurry having a concentration of 0.4% by weight. The paper was made by using a Fourdrinier paper machine equipped with a stack former in the wire portion to obtain a spacer paper for glass plates with a basis weight of 55 g/m ² . In the above-mentioned wire section, adjustment was made so that the difference between the dewatering ratios of the folded wire formers on both sides of the wet paper (the dewatering ratio of the upper folded wire formers as a reference) became 10% or less.

[Comparative Example 1]

A spacer paper for a glass plate having a basis weight of 55 g/m ² was obtained by the same method as in Example 1 except that the web former was not used.

[Comparative Example 2]

In addition, the same procedure as in the production of the above-mentioned softwood bleached kraft pulp was carried out, except that a polysiloxane-based defoamer "SN Defoamer 551K" (manufactured by San nopco) was used as a defoamer and the above-mentioned solvent cleaning was not performed. A spacer paper for a glass plate having a basis weight of 55 g/m ² was obtained in the same manner as in Example 1, except that 100 parts by mass of the conifer bleached kraft pulp was obtained and the conifer bleached kraft pulp was used.

Regarding the polysiloxane content of Examples and Comparative Examples, Example 1 was 0.1 ppm, Comparative Example 1 was 0.1 ppm, and Comparative Example 2 was 2.3 ppm. The number of non-colored discontinuous regions on one side of Example 1 was 8 per 1000 m ² and 11 per 1000 m ² on the other side. The number of non-colored discontinuous regions on one side of Comparative Example 1 was 8 per 1000 m ² and 16 per 1000 m ² on the other side. In the transport test, the transfer of the glass plates obtained in the examples and the comparative examples to the glass plates with the spacer paper was confirmed. As a result, no color was found when an array of liquid crystal panels was formed using the glass plates using the spacer paper of Example 1. Membrane disconnection. On the other hand, when the array of the liquid crystal panel was formed using the glass plate using the spacer paper for glass plates of Comparative Example 1 and Comparative Example 2, the disconnection of the color film was found.

Claims (15)

A spacer paper for glass plates, which uses wood pulp as a raw material, and has a polysiloxane content of 0.5 ppm or less, and the number of discontinuous regions containing polysiloxane with a diameter of 30 μm or more on one surface and 30 μm on the other surface. The difference in the number of discontinuous regions containing polysiloxane with the above diameters is within 5 pieces/1000m ² . The spacer paper for a glass plate according to claim 1, wherein the number of the discontinuous regions on one surface is 15 pieces/1000 m ² or less. The spacer paper for glass plates according to claim 1 or 2, wherein the content of polysiloxane is 0.1 ppm or less. The spacer paper for a glass plate according to claim 1 or 2, wherein the polysiloxane is polysiloxane oil. The spacer paper for a glass plate according to claim 4, wherein the polysiloxane oil is dimethyl polysiloxane. The spacer paper for a glass plate according to claim 1 or 2, which has a thickness of 20 to 200 μm. The spacer paper for a glass plate according to claim 1 or 2, wherein the mean deviation (MMD) of the friction coefficient of the surface obtained by the KES method is 0.022 or less. The spacer paper for a glass plate according to claim 1 or 2, wherein the glass plate is for a display. The spacer paper for a glass plate according to claim 8, wherein the display is a TFT liquid crystal display or an organic EL display. A laminate comprising the spacer paper for a glass plate according to any one of claims 1 to 9, and a glass plate. A method for protecting a glass plate, comprising the step of disposing the spacer paper for a glass plate according to any one of claims 1 to 9 between the glass plates. A manufacturing method, which is the manufacturing method of the spacer paper for glass plates according to any one of Claims 1 to 9, which at least comprises the following steps: a slurry preparation step, preparing a pulp of wood pulp; a sheet forming step, The slurry is made into a sheet; the wet paper preparation step is to dehydrate the sheet to form wet paper; and the drying step is to dry the wet paper to obtain the spacer paper; and in the wet paper preparation step, from Both sides of the above sheet were dehydrated. The manufacturing method according to claim 12, wherein the dehydration is performed by suction. The manufacturing method according to claim 13, wherein the difference between the dehydration ratio of the suction on one surface of the sheet and the dehydration ratio of the suction on the other surface is the dehydration ratio of the suction on the other surface. 10% or less. The manufacturing method according to claim 13 or 14, comprising an additional suction step of further suctioning both sides of the spacer paper after the drying step.