WO2018181658A1

WO2018181658A1 - Glass plate slip sheet and production method therefor

Info

Publication number: WO2018181658A1
Application number: PCT/JP2018/013108
Authority: WO
Inventors: 浅井　靖彦; 孝之西村
Original assignee: 特種東海製紙株式会社
Priority date: 2017-03-30
Filing date: 2018-03-29
Publication date: 2018-10-04
Also published as: CN110446813B; TW201840929A; JPWO2018181658A1; TWI729282B; KR20180135855A; JP6598229B2; CN110446813A; KR102064252B1

Abstract

The present invention pertains to a glass plate slip sheet having timber pulp as the raw material therefore and having a short fiber content of no more than 10.5% by mass, said short fibers having a fiber length of no more than 200 µm. This glass plate slip sheet is capable of solving the problems caused by differences in the state of front and rear surfaces.

Description

Interleaving paper for glass plate and method for producing the same

In the process of laminating and storing and transporting a plurality of glass plates for flat panel displays such as liquid crystal displays, plasma displays, organic electroluminescence (organic EL) displays, etc., the paper for packaging the glass plates, and The present invention relates to paper sandwiched between glass plates and the production of these papers.

In general, in the storage process of laminating and storing a plurality of glass plates for flat panel displays, the distribution process of transporting them with trucks, etc., the glass plates are subjected to impacts and come into contact with each other. In order to prevent the glass surface from being contaminated by contaminants from the outside, paper called interleaving paper is sandwiched between glass plates.

Glass plates for flat panel displays are used for high-definition displays compared to general architectural window glass plates, vehicle window glass plates, etc., so impurities on the glass surface are as much as possible on the glass surface. It is required to have a clean surface, and to have excellent flatness for high-speed response and widening of the viewing angle.

Several slip sheets have already been proposed for use in such applications, as slip sheets that can prevent the glass plate from cracking and scratching the surface, and slip sheets that do not contaminate the glass surface. For example, Patent Document 1 discloses a technique for forming a fluorine coating film on the surface of a slip sheet. Further, Patent Document 2 includes a paper sheet in which a polyethylene resin foam sheet and a polyethylene resin film are bonded, and Patent Document 3 includes a paper made of pulp containing 50 mass% or more of exposed chemical pulp. In addition, there is a paper for glass containing a specific alkylene oxide adduct and water-soluble polyether-modified silicone, and Patent Document 4 defines the amount of resin in the paper and considers contamination of the glass surface. A glass sheet slip sheet using the prepared raw materials is disclosed.

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

For example, it is known that problems such as disconnection may occur if the glass plate surface is contaminated during the production of a color filter substrate in an array process, which is one of the manufacturing processes of a TFT liquid crystal display. The color filter substrate is made by forming a thin film such as a semiconductor film, ITO film (transparent conductive film), insulating film, aluminum metal film, etc. on a glass plate by sputtering or vacuum evaporation, but it is a contaminant on the glass plate surface. This is because a circuit pattern formed from a thin film is disconnected or a short circuit occurs due to a defect in the insulating film. In the production of a color filter substrate, a photolithography pattern is formed on a glass plate. If contaminants are present on the glass plate surface during resist coating in this process, pinholes are generated in the resist film after exposure and development. As a result, disconnection or short circuit occurs. Similar problems have been confirmed in the manufacture of organic EL displays. An organic EL display is manufactured by forming a thin film such as an ITO anode, an organic light emitting layer, or a cathode on a glass substrate by sputtering, vapor deposition, printing, etc., and therefore does not emit light when a foreign substance that obstructs the thin film exists on the glass substrate surface. Problems arise.

Such a cause of contamination of the glass plate has been difficult to identify, but it has been found that one of the causes is a fine foreign substance that is transferred from the surface of the glass plate interleaf to the surface of the glass plate.

It has also been found that the short fibers contained in the glass sheet interleaving paper attract such foreign substances.

By the way, when sandwiching the glass sheet interleaf paper between the glass sheets, if there is a difference in the physical state of the front and back surfaces of the interleaving sheet, consider that the specific surface of the interleaf sheet is in contact with the surface of the glass sheet. There may be a need. For example, a glass plate for a flat panel display has a fine circuit formed on its surface, so even if it is a very small amount of foreign matter, its adhesion is particularly avoided. When there are more short fibers on the one surface of the other surface than the other surface, the short fibers attract a foreign substance and the risk that the foreign substance is transferred to the surface of the glass plate is increased. Care should be taken to bring the slip sheet in contact with the surface of the glass plate so that the surface with few short fibers is in contact with the surface of the glass plate. In this case, it is conceivable to sandwich two interleaf sheets between glass plates, and the surface of each interleaving paper with the smaller amount of short fibers facing the glass plate can be considered, but the use amount of interleaving paper increases. However, since the weight of the laminate of the slip sheet and the glass plate increases, it is not preferable in terms of handling.

This invention makes it the subject to solve said problem originating in the difference in the state of the front and back surfaces of the paper for glass plates. In particular, an object of the present invention is to provide a slip sheet for a glass plate that may be brought into contact with either the front or back glass plate.

Thus, as a result of intensive studies, the present inventors originally suppressed the difference in the amount of short fibers present on the front and back surfaces of the slip sheet by reducing the amount of short fibers contained in the slip sheet for glass plate. It is found that the difference in the state of the front and back surfaces of the glass sheet interleaf can be suppressed, and as a result, it is possible to provide a glass sheet interleaf that may be brought into contact with either the front or back surface of the glass sheet. Completed the invention.

A first aspect of the present invention is a glass sheet interleaf made of wood pulp, wherein the content of short fibers having a fiber length of 200 μm or less is 10.5% by weight or less. It is.

The content of the short fiber is preferably 1.2% by weight or more.

The average fiber diameter of the short fibers is preferably 10 to 50 μm.

The abundance of the short fibers on the surface of the glass sheet interleaf is preferably 300 to 850 fibers / m ² .

The difference between the short fiber existing amount on one surface of the glass sheet interleaf and the short fiber existing amount on the other surface is 15% or less of the short fiber existing amount on the other surface. Is preferred.

The thickness of the glass sheet interleaf is preferably 20 to 200 μm.

The glass sheet slip sheet preferably has an average deviation (MMD) of the friction coefficient of the surface by the KES method of 0.022 or less.

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

A second aspect of the present invention is a method for producing the above glass sheet interleaving paper,
A slurry preparation step for preparing a wood pulp slurry;
A sheet forming step for forming the slurry into a sheet;
A wet paper web preparation step for dehydrating the sheet to form a wet paper web;
Including at least a drying step of drying the wet paper to obtain the slip sheet;
The present invention relates to a manufacturing method in which dehydration is performed from both sides of the sheet in the wet paper preparation step.

It is preferable to perform the dehydration by suction.

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

It is preferable that the manufacturing method includes an additional suction step of further sucking both sides of the interleaving paper after the drying step.

Further, the present invention also relates to the glass sheet interleaving paper according to the first aspect of the present invention and a laminate with the glass sheet.

And this invention relates also to the protection method of the glass plate including the process of arrange | positioning the paper for glass plates of the 1st aspect of this invention between glass plates.

Since the amount of short fibers contained in the interleaving paper for glass plate of the present invention is small, the difference in the amount of short fibers on the front and back surfaces of the interleaving paper is suppressed, and the difference in the state of the front and back surfaces of the interleaving paper for glass plates Is suppressed. Therefore, either of the front and back surfaces of the slip sheet for glass plate of the present invention may be brought into contact with the glass plate. Thereby, the paper for glass plates of this invention is excellent in the handleability.

In addition, glass sheet interleaving paper is originally wound in a roll shape and shipped, but in the wound state, the front (front) surface and back surface of the interleaving paper are in contact with each other. When there are many short fibers on the surface, the short fibers on the surface of the slip sheet are transferred to the back surface in the wound state even when trying to bring the back surface of the slip sheet into contact with the surface of the glass plate. There is a risk that the cleanliness of the back surface will be reduced.

However, the slip sheet for the glass plate of the present invention has a roll shape because the transition of the short fibers from one surface of the slip sheet to the other surface is suppressed even when it is wound into a roll shape. There is no need to worry about a reduction in the cleanliness of the surface of the interleaving paper due to winding.

Furthermore, since the interleaving paper for glass plate of the present invention has a small amount of short fibers that attract foreign matter, it is possible to effectively suppress or avoid the transfer of fine foreign matter that becomes a problem from the interleaving paper to the glass plate. . In this way, by suppressing or avoiding the transfer of fine foreign matter that becomes a problem on the glass plate, it becomes possible to prevent circuit disconnection of a color film or the like in a manufacturing process of a TFT liquid crystal display or the like.

A first aspect of the present invention is a glass sheet interleaf made of wood pulp, wherein the content of short fibers having a fiber length of 200 μm or less is 10.5 based on the weight of the glass sheet interleaf. It is a slip sheet for glass plate that is not more than wt%.

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

The form of the wood pulp is not particularly limited, and can take any form such as a sheet, a block, or a flake. The sheet-like pulp can be obtained using, for example, a pulp machine having four steps of wire part, press part, dry part, and finishing. In the wire part, pulp fiber is made using a long mesh or a vacuum filter, and in the press part, it is dehydrated using a roll press. In the dry part, it is dried with a cylinder dryer or a fract dryer, and finally both ends of the sheet pulp are cut off and wound up on a roll. Such a method is described in detail in the “Paper Pulp Manufacturing Technology Series” published by the Paper Pulp Technology Association and “Paper Pulp Manufacture”. The block-like pulp can be obtained, for example, by laminating the sheet-like pulp, and the flake-like pulp can be obtained, for example, by pulverizing the sheet-like pulp.

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

The basis weight of the sheet pulp is preferably 400 to 1300 g / m ² , more preferably 500 to 1200 g / m ² , still more preferably 500 to 1100 g / m ² , and 500 to 1000 g. / M ² is more preferable, and 700 to 1000 g / m ² is even more preferable.

In the interleaving paper for glass plate of the present invention, the content of short fibers having a fiber length of 200 μm or less contained in the interleaving paper is limited to 10.5% by weight or less based on the weight of the interleaving paper. The content of short fibers is preferably 10.0% by weight or less, more preferably 9.5% by weight or less, and even more preferably 9.0% by weight or less.

On the other hand, the content of short fibers having a fiber length of 200 μm or less contained in the slip sheet for glass plate of the present invention is preferably not 0 in terms of maintaining the strength of the slip sheet and adjusting the air permeability. % Or more is more preferable, 0.8% by weight or more is even more preferable, and 1.2% by weight or more is even more preferable.

The short fiber has a fiber length of 200 μm or less. Here, “fiber length” does not mean the average fiber length. Accordingly, 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 fiber length refers to the length of the fiber when the fiber is straightened. The content of short fibers having a fiber length of 200 μm or less can be measured, for example, by slurrying slip sheets and measuring the number of short fibers of 200 μm or less in the slurry.

The average fiber diameter of the short fibers is preferably 10 μm to 50 μm, more preferably 12 μm to 40 μm, and even more preferably 15 μm to 30 μm. Here, the “average fiber diameter” means the number average of the fiber diameters of the short fibers. The average fiber diameter is obtained by, for example, magnifying and observing a plurality of positions on the surface of the interleaf paper for a glass plate with an electron microscope, randomly selecting a predetermined number of fibers from each electron microscope image, and determining the diameter of the selected fibers. Measured and averaged. The number of fibers to be selected is 100 or more, preferably 150 or more, more preferably 200 or more, and even more preferably 300 or more. The average fiber diameter of the short fibers can also be measured, for example, by slurrying slip sheets and averaging the fiber diameters of short fibers of 200 μm or less in the slurry.

The abundance of the short fibers on the surface of the glass sheet interleaf of the present invention is preferably 300 to 850 / m ² , more preferably 330 to 800 / m ² , and 350 to More preferably, it is 750 / m ² . When the amount of short fibers is relatively small, the amount of foreign matter attracted by the short fibers can be reduced.

In the slip sheet for glass plate of the present invention, the difference between the amount of the short fibers on one surface and the amount of the short fibers on the other surface is 15% of the amount of the short fibers on the other surface. Or less, more preferably 12% or less, even more preferably 10% or less. That is, in the interleaving paper for a glass plate of the present invention, it is preferable that the amount of short fibers on one surface does not vary so much as to be within the above specific range from the amount of short fibers on the other surface. Here, the “abundance” means the number of the short fibers per unit area of the surface of the slip sheet, for example, by observing a plurality of positions on the surface of the slip sheet for the glass plate with an electron microscope, It can be determined by averaging the number of short fibers observed at the location per unit area. It can also be determined by obtaining the number of short fibers of 200 μm or less per unit area from fibers dropped by rubbing a predetermined area with a sheet or the like with the surface of the interleaf facing downward. Furthermore, it can also be determined by dividing the slip sheet into two very thin sheets at the center in the thickness direction, slurrying each sheet, and measuring the number of short fibers of 200 μm or less in the slurry. Alternatively, the abundance of short fibers can also be determined by thoroughly washing the surface of a predetermined area of the glass sheet interleaf with water, and using the dropped fibers in a fiber length measuring machine.

Since the amount of short fibers contained in the interleaving paper for the glass plate of the present invention is small, it is possible to suppress fluctuations in the abundance of short fibers on the front and back surfaces of the interleaving paper. Differences in the physical state of the front and back surfaces are suppressed. In particular, the amount of foreign matter attracted by the short fibers is reduced, and the amount of foreign matter is not greatly different between the front and back surfaces of the slip sheet. Accordingly, the interleaving paper for glass plate of the present invention may be brought into contact with either the front or back surface of the glass plate.

The foreign matter that is a problem in the present invention is a fine foreign matter that contaminates the surface of the glass plate.

The foreign material may be either solid or liquid. Further, the size of the foreign matter is not particularly limited, but is 0.1 μm to 50 μm, preferably 0.1 μm to 40 μm. More preferably, the thickness is 0.1 μm to 30 μm. Here, “size” means a volume average (median) particle diameter. The volume average particle diameter can be measured, for example, by a laser diffraction scattering method.

The foreign matter may include a hydrophobic substance. In addition, the foreign matter may be composed only of a hydrophobic substance.

The hydrophobic substance is not particularly limited. The hydrophobic substance is preferably non-volatile, and oils (excluding silicone oils. For example, aliphatic hydrocarbons, vegetable oils, animal oils, synthetic glycerides, fatty alcohols, fatty acids, fatty alcohols and / or esters of fatty acids). More preferably selected from the group consisting of resins (excluding silicones), silicones, pitches, rubbers, and talc, especially talc adsorbing hydrophobic foreign matter, especially silicone and talc (especially hydrophobic foreign matter) And still more preferably selected from the group consisting of:

Aliphatic hydrocarbons include, for example, linear or branched hydrocarbons, especially mineral oil (liquid paraffin, etc.), paraffin, petrolatum, ie petrolatum, naphthalene, etc .; hydrogenated polyisobutene, isoeicosane, polydecene, pearl reamer, etc. And polyisobutenes and decene / butene copolymers; and mixtures thereof.

As examples of other aliphatic hydrocarbons, mention may also be made of linear or branched or optionally cyclic C ₆ -C ₁₆ lower alkanes. Examples that may be mentioned include hexane, undecane, dodecane, tridecane and isoparaffins such as isohexadecane and isodecane.

Examples of vegetable oils include, for example, linseed oil, camellia oil, macadamia nut oil, sunflower oil, apricot oil, soybean oil, arara oil, hazelnut oil, corn oil, olive oil, avocado oil, sasanqua oil, castor oil, safflower Mention may be made of oil, jojoba oil, almond oil, grape seed oil, sesame oil, peanut oil, and mixtures thereof.

Examples of animal oils include, for example, mink oil, squalene, perhydrosqualene and squalane.

Examples of synthetic glycerides include caprylic / capric triglycerides.

Fatty acids should be in acidic form (ie, not in salt form to avoid soaping) and may be saturated or unsaturated and have 6 to 30 carbon atoms, especially 9 to 30 carbons. Contains atoms and is optionally substituted, in particular with one or more hydroxyl groups (especially 1 to 4). When the fatty acid is unsaturated, the compound can contain 1 to 3 conjugated or non-conjugated carbon-carbon double bonds. The fatty acid is selected from, for example, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, linoleic acid, linolenic acid and isostearic acid.

The term “aliphatic alcohol” as used herein means any saturated, linear or branched C ₈ -C ₃₀ alcohol, optionally with one or more hydroxyl groups ( In particular 1 to 4).

Of the aliphatic alcohols, C ₁₂ -C ₂₂ aliphatic alcohols are preferred, and C ₁₆ -C ₁₈ saturated aliphatic alcohols are more preferred. Among these, lauryl alcohol, cetyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, behenyl alcohol, undecyl alcohol, myristyl alcohol, and mixtures thereof can be mentioned.

Examples of esters of fatty acids and / or fatty alcohols are saturated or unsaturated, linear or branched C ₁ -C ₂₆ aliphatic mono- or polyacid esters, and saturated or unsaturated, linear Specific examples include C ₁ -C ₂₆ aliphatic monohydric alcohols or polyhydric alcohol esters, and the total number of carbon atoms in the ester is preferably 10 or more.

Resin (excluding silicone) is not particularly limited as long as it is hydrophobic. Examples of the resin include thermoplastic resins such as polyolefin, polystyrene, poly (meth) acrylate, polyacrylamide, polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polyester, polycarbonate, polyamide, polyimide, polyurethane, melamine resin, and urea resin. And the like, and a mixture thereof.

Silicone includes silicone oil. Silicone oil is hydrophobic and its molecular structure may be cyclic, linear or branched. Kinematic viscosity at 25 ° C. of the silicone oil is usually in the range of 0.65 ~ 100,000mm ² / s, it may be in the range of 0.65 ~ ^10,000mm 2 / s.

Examples of the silicone oil include linear organopolysiloxanes, cyclic organopolysiloxanes, and branched organopolysiloxanes.

Examples of the linear organopolysiloxane, cyclic organopolysiloxane, and branched organopolysiloxane include the following general formulas (1), (2), and (3):

R ¹ ₃ SiO— (R ¹ ₂ SiO) _a —SiR ¹ ₃ (1)

R ¹ _(4-c) Si (OSiR ¹ ₃ ) _c (3)

(Where
Each R ¹ is independently a hydrogen atom, a hydroxyl group, or a group selected from a group represented by a substituted or unsubstituted monovalent hydrocarbon group or an alkoxy group;
a is an integer of 0 to 1000;
b is an integer of 3 to 100,
c is an integer of 1 to 4, preferably an integer of 2 to 4)
The organopolysiloxane represented by these is mentioned.

The substituted or unsubstituted monovalent hydrocarbon group is typically a substituted or unsubstituted one having 1 to 30 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 4 carbon atoms. A saturated saturated hydrocarbon group; a substituted or unsubstituted monovalent unsaturated hydrocarbon group having 2 to 30 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms; A monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms, more preferably 6 to 12 carbon atoms.

Examples of the monovalent saturated hydrocarbon group having 1 to 30 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. A linear or branched alkyl group such as a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group and a decyl group, and a cycloalkyl group such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and a cyclooctyl group. Can be mentioned.

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

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 mesityl group. A phenyl group is preferred. In addition, in this specification, the aromatic hydrocarbon group includes a group in which an aromatic hydrocarbon and an aliphatic saturated hydrocarbon are combined in addition to a group consisting of only an aromatic hydrocarbon. Examples of the group in which an aromatic hydrocarbon and a saturated hydrocarbon are combined include an aralkyl group such as a benzyl group or a phenethyl group.

The hydrogen atom on the monovalent hydrocarbon group may be substituted with one or more substituents, and examples of the substituent include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom and an iodine atom), a hydroxyl group , Carbinol group, epoxy group, glycidyl group, acyl group, carboxyl group, amino group, methacryl group, mercapto group, amide group, oxyalkylene group and the like. Specifically, 3,3,3-trifluoropropyl group, 3-chloropropyl group, 3-hydroxypropyl group, 3- (2-hydroxyethoxy) propyl group, 3-carboxypropyl group, 10-carboxydecyl group And 3-isocyanatopropyl group.

Examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group, but a methoxy group or an ethoxy group is preferable, and a methoxy group is more preferable.

More specifically, the linear organopolysiloxane may be a trimethylsiloxy group-blocked dimethylpolysiloxane having a molecular chain at both ends (a low-viscosity dimethylsilicone such as 2 mPa · s or 6 mPa · s to a high viscosity such as 1 million mPa · s). ), Organohydrogenpolysiloxane, trimethylsiloxy group-capped methylphenyl polysiloxane with both molecular chains, trimethylsiloxy group-capped dimethylsiloxane / methylphenylsiloxane copolymer with both molecular chains, trimethylsiloxy group-capped diphenylpolysiloxane with both molecular chains , A trimethylsiloxy group-capped dimethylsiloxane / diphenylsiloxane copolymer, both ends of a molecular chain, trimethylpentaphenyltrisiloxane, phenyl (trimethylsiloxy) siloxane, Polyalkylpolysiloxane, trimethylsiloxy group-capped dimethylpolysiloxane / methylalkylsiloxane copolymer with both ends of the molecular chain, trimethylsiloxy group-capped dimethylsiloxane / methyl (3,3,3-trifluoropropyl) siloxane with molecular chain at both ends Combined, 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, tristrimethylsiloxymethylsilane, tristrimethylsiloxyalkylsilane, Tetrakistrimethylsiloxysilane, tetramethyl-1, -Dihydroxydisiloxane, octamethyl-1,7-dihydroxytetrasiloxane, hexamethyl-1,5-diethoxytrisiloxane, hexamethyldisiloxane, octamethyltrisiloxane, higher alkoxy modified silicone, higher fatty acid modified silicone, dimethiconol, etc. Is done.

Cyclic organopolysiloxanes include hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6), 1,1-diethylhexamethyl. Cyclotetrasiloxane, phenylheptamethylcyclotetrasiloxane, 1,1-diphenylhexamethylcyclotetrasiloxane, 1,3,5,7-tetravinyltetramethylcyclotetrasiloxane, 1,3,5,7-tetramethylcyclotetra Siloxane, 1,3,5,7-tetracyclohexyltetramethylcyclotetrasiloxane, tris (3,3,3-trifluoropropyl) trimethylcyclotrisiloxane, 1,3,5,7-tetra (3-methacryloxyp Pyr) tetramethylcyclotetrasiloxane, 1,3,5,7-tetra (3-acryloxypropyl) tetramethylcyclotetrasiloxane, 1,3,5,7-tetra (3-carboxypropyl) tetramethylcyclotetrasiloxane 1,3,5,7-tetra (3-vinyloxypropyl) tetramethylcyclotetrasiloxane, 1,3,5,7-tetra (p-vinylphenyl) tetramethylcyclotetrasiloxane, 1,3,5, 7-tetra [3- (p-vinylphenyl) propyl] tetramethylcyclotetrasiloxane, 1,3,5,7-tetra (N-acryloyl-N-methyl-3-aminopropyl) tetramethylcyclotetrasiloxane, 1 , 3,5,7-Tetra (N, N-bis (lauroyl) -3-aminopropyl) tetramethyl Cyclotetrasiloxane and the like.

Examples of the branched organopolysiloxane include methyltristrimethylsiloxysilane, ethyltristrimethylsiloxysilane, propyltristrimethylsiloxysilane, tetrakistrimethylsiloxysilane, and phenyltristrimethylsiloxysilane.

As the silicone oil in the present invention, dimethylpolysiloxane, diethylpolysiloxane, methylphenylpolysiloxane, polydimethyl-polydiphenylsiloxane copolymer, polymethyl-3,3,3-trifluoropropylsiloxane and the like are preferable. As the silicone in the present invention, dimethylpolysiloxane is typical.

The silicone oil in the present invention may be a modified silicone oil. Examples of the modified silicone oil include polyoxyalkylene-modified silicone oil.

The polyoxyalkylene-modified silicone oil is a silicone oil having a polyoxyalkylene group bonded to the molecule via a silicon-carbon bond, and preferably exhibits water solubility at room temperature, specifically at 25 ° C. More preferably, it is a nonionic one.

Specifically, the polyoxyalkylene-modified silicone oil is, for example, a copolymer of a silicone oil composed of linear or branched siloxane and a polyoxyalkylene, and there are various types. ) Is preferred.

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

(Where
R ¹ is independently the same as above,
Each 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, and G is a carbon number of 2 to 5 such as ethylene oxide or propylene oxide. A polyoxyalkylene group comprising at least one alkylene oxide of
d represents an integer of 1 to 500;
e represents an integer of 1 to 50).

Examples of the substituted or unsubstituted divalent hydrocarbon group include a linear or branched divalent hydrocarbon group having 1 to 30 carbon atoms. Specific examples include a methylene group, a dimethylene group, and trimethylene. A linear or branched alkylene group having 1 to 30 carbon atoms such as a group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group; vinylene group, arylene group, butenylene group, Alkenylene groups having 2 to 30 carbon atoms such as hexenylene group and octenylene group; arylene groups having 6 to 30 carbon atoms such as phenylene group and diphenylene group; alkylene arylene groups having 7 to 30 carbon atoms such as dimethylenephenylene group And hydrogen atoms bonded to carbon atoms of these groups are at least partially halogen atoms such as fluorine, hydroxyl groups, The carbinol group, epoxy group, a glycidyl group, an acyl group, a carboxyl group, an amino group, a methacryl group, a mercapto group, an amide group, and substituted groups in the organic group containing an oxyalkylene group or the like. The divalent hydrocarbon group is preferably an alkylene group having 1 to 30 carbon atoms, more preferably an alkylene group having 1 to 6 carbon atoms, and more preferably an alkylene group having 3 to 5 carbon atoms.

For example, specific examples of the polyoxyalkylene-modified silicone oil include the following.

(Where
x is 20 to 160, y is 1 to 25, and the value of x / y is 50 to 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 , where m is 7 to 40, n is 0 to 40, m + n The value of is at least 1 and may be graft polymerized or randomly polymerized, and R ⁴ represents a hydrogen atom or the above substituted or unsubstituted monovalent hydrocarbon group. Preferably, m is 7-30 and n is 0-30)

In addition, examples of the modified silicone oil include aminoalkyl-modified silicone oil.

The aminoalkyl-modified silicone oil is a silicone oil in which an aminoalkyl group is bonded to the molecule via a silicon-carbon bond, and preferably exhibits a viscosity of 10 to 100,000 cs at room temperature, specifically at 25 ° C. It is.

As the aminoalkyl silicone oil, in the above formula (4), G is represented by the formula: — (NR ⁴ CH ₂ CH ₂ ) _z NR ⁴ ₂ (wherein R ⁴ is independently as defined above, z Is a number of 0 ≦ z ≦ 4).

In the present invention, when the foreign material is silicone, the amount of silicone contained in the interleaf paper for glass plate is preferably 0.5 ppm or less, and 0.4 ppm or less based on the absolute dry mass of the interleaf paper. More preferably, 0.3 ppm or less is even more preferable, 0.2 ppm or less is even more preferable, and 0.1 ppm or less is particularly preferable. When there is more than 0.5ppm of silicone, color film breaks caused by a small amount of silicone transferred to the glass in high-definition scenes such as mobile devices that require a very high-definition display are highly detailed. This is because there is an increased risk of being conspicuous and being judged as a quality defect. In the present invention, “absolutely dry” means a state in which moisture is not substantially present in an object to be dried by drying.

The thickness of the slip sheet for 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. Thus, by using a relatively thin slip sheet, the difference in physical state between the front and back of the slip sheet can be further suppressed.

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

In the slip sheet for glass plate of the present invention, the average deviation (MMD) of the friction coefficient of the surface by the KES method is preferably 0.022 or less, preferably 0.020 or less, and 0.019 or less. More preferably, it is still more preferably 0.018 or less, and still more preferably 0.017 or less. MMD uses a friction tester (KES-SE manufactured by Kato Tech Co., Ltd.), and a 10 mm square friction element consisting of a bundle of piano wires with a diameter of 0.5 mm is fixed with a tension of 20 g / cm. Is an average deviation value of the coefficient of friction measured by moving 2 cm at a sample moving speed of 0.1 cm / second in the same direction as the direction in which the tension is applied while contacting with a contact pressure of 50 g / cm ² . When this MMD is large, it means that the coefficient of friction of the paper surface varies greatly depending on the position of the paper surface. Microscopically, it means that minute irregularities on the surface of the paper increase. By providing fine irregularities on the surface of the slip sheet in this way, the friction coefficient between the surface of the glass plate and the surface of the slip sheet is reduced, and the removal work when removing the slip sheet from the surface of the glass sheet is facilitated. . If the MMD exceeds 0.022, minute irregularities on the surfaces of the papers increase and the catching between the papers increases, which is not preferable. For example, the MMD is preferably 0.001 to 0.022, more preferably 0.002 to 0.020, and still more preferably 0.004 to 0.019.

The slip sheet for glass plate of the present invention can be produced on the basis of a usual method such as a papermaking method.

The second aspect of the present invention is a method for producing a glass sheet interleaving paper,
A slurry preparation step for preparing a wood pulp slurry;
A sheet forming step for forming the slurry into a sheet;
A wet paper web preparation step for dehydrating the sheet to form a wet paper web;
Including at least a drying step of drying the wet paper to obtain the slip sheet;
In the wet paper preparation step, the dehydration is performed from both sides of the sheet slurry.

In the slurry preparation step, a wood pulp slurry can be prepared by a conventionally known method. For example, in the slurry preparation step, cellulose fibers constituting the wood pulp are disaggregated to prepare an aqueous suspension to prepare a slurry.

In addition, as long as the performance of the present invention is not impaired, the above-mentioned slurry, if necessary, an adhesive, an antifungal agent, an antifoaming agent, a filler, a wet paper strength enhancer, a dry paper strength enhancer, a sizing agent, Coloring agents, fixing agents, yield improvers, slime control agents and the like can be added. In addition, it is preferable to pay close attention when adding these chemicals so that insects, dust and the like are not mixed.

In general, wood pulp and interleaf paper often contain silicone. This is because a silicone-based antifoaming agent is frequently used as an antifoaming agent used to prevent deterioration in cleaning ability due to generation of foam in the production process of wood pulp and interleaf paper, particularly in the cleaning process. Antifoam-derived silicone remains in the pulp and interleaf. The silicone-based antifoaming agent is produced, for example, by mixing a modified silicone, a surfactant or the like with a mixture of silicone oil and hydrophobic silica.

Talc is an inorganic powder obtained by pulverizing talc, and is a hydrous magnesium silicate having a general structure: Mg ₃ (SiO ₂ ) ₂ (OH) ₂ or Mg ₃ Si ₄ O ₁₀ (OH) ₂ having a layered structure. Talc is used as a filler, pitch control agent, coating agent and the like.

In the second aspect of the present invention, a non-silicone antifoaming agent is used as an antifoaming agent in the case of using an antifoaming agent in order to reduce the content of a foreign matter that is a problem contained in the interleaf paper for glass plate. When using a filler, it is preferable to use a filler other than talc. Furthermore, it is preferable to use wood pulp obtained by using a non-silicone antifoaming agent and / or wood pulp not containing talc.

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, and amine-based antifoaming agents. , Phosphate ester defoamers, metal soap defoamers, sulfonate ester defoamers, polyether defoamers and vegetable oil defoamers.

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

Higher alcohol-based antifoaming agents include, for example, octyl alcohol, hexadecyl 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 antifoaming agent includes, for example, isoamyl stearate, glycerin monoricinoleate, sorbitol monolaurate, soliitol trioleate and the like.

The amide antifoaming agent includes, for example, acrylate polyamine.

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

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

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

Examples of the sulfonic acid ester-based antifoaming agent include sodium lauryl sulfonate, sodium dodecyl sulfonate, and the like.

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, polyoxyethylene polyoxypropylene (Poly) oxyalkylene alkyl ethers such as 2-ethylhexyl ether, higher alcohols having 8 or more carbon atoms and secondary alcohols having 12 to 14 carbon atoms such as oxyethyleneoxypropylene adducts; polyoxypropylene phenyl ether, polyoxy (Poly) oxyalkylene (alkyl) aryl ethers such as ethylene nonylphenyl ether; 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,5-dimethyl-3-he Acetylene ethers obtained by addition polymerization of alkylene oxide to acetylene alcohols such as syn-2,5-diol and 3-methyl-1-butyn-3-ol; diethylene glycol oleate, diethylene glycol laurate, ethylene glycol distearate (Poly) oxyalkylene fatty acid esters such as polyoxyethylene sorbitan monolaurate, (poly) oxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan trioleate; polyoxypropylene methyl ether sodium sulfate, polyoxyethylene (Poly) oxyalkylene alkyl (aryl) ether sulfate esters such as sodium dodecylphenol ether sulfate; (poly) oxyethylene Nsutearirurin acid esters of (poly) oxyalkylene alkyl phosphoric acid esters; polyoxyethylene such as polyoxyethylene lauryl amine (poly) oxyalkylene alkyl amines; containing polyoxyalkylene amide.

Plant oil-based antifoaming agents include, for example, vegetable oils such as soybean oil, corn oil, coconut oil, linseed oil, rapeseed oil, cottonseed oil, sesame oil, castor oil and the like.

Further, the non-silicone antifoaming agent can include inorganic particles such as hydrophobic silica. As the hydrophobic silica, it is preferable to use silica hydrophobized by substituting silanol groups of hydrophilic silica with alkyl groups such as methyl groups.

The non-silicone antifoaming agent can contain a surfactant or the like as necessary. Accordingly, the non-silicone antifoaming agent may be an emulsion type.

As fillers other than talc, inorganic fillers such as kaolin, calcium carbonate, titanium oxide, and barium sulfate, and organic fillers such as urea resin can be used.

When preparing the slurry, if the beating of the wood pulp is advanced, the effect of increasing the paper interlayer strength can be expected. However, if the short fibers increase by proceeding with beating, there is a possibility that inconveniences such as attracting foreign substances or generating paper dust during use as interleaving paper, it is not preferable to advance the beating degree more than necessary. . In the present invention, the preferred beating degree is 300 to 650 ml c. s. f. It is.

In the sheet forming step in which the slurry is formed into a sheet, the sheet can be formed by a conventionally known method. For example, by discharging the slurry onto a flat wire (for example, a long net paper machine) or by scooping a sheet from the slurry with a wire wound around a cylindrical cylinder (for example, a circular paper machine) , You can get a sheet.

In the second aspect of the present invention, dehydration is performed from both sides of the sheet in a wet paper preparation step in which the sheet is dehydrated to form a wet paper. Thereby, the short fiber which has the fiber length of 200 micrometers or less contained in the said sheet | seat is removed effectively from a sheet | seat. The method of dehydration is arbitrary, and a conventionally known method can be used. For example, there is a method of making paper using a twin wire type paper machine such as an on-top former or a gap former. Moreover, adjustment by a press part can be considered, for example, it can dehydrate by pressing the said sheet | seat with a roll. However, it is preferable to perform the dehydration by suction for effective removal of the short fibers.

In the process of dehydrating from both sides of the sheet, for example, the sheet extending in the horizontal direction is sandwiched from above and below by a net, and may be dehydrated by suction by a suction device in the vertical direction. Because there is a difference between the suction force and the downward suction force, there is a possibility that more short fibers may remain on the sheet surface on the upper side compared to the sheet surface on the lower side. It is preferable that the sheet extending in the vertical direction is sandwiched by a net and sucked in the left-right direction to be dehydrated. In this case, it is preferable to maintain the moving direction of the wet paper so as to be in the vertical direction or in an inclined range within 30 ° from the vertical direction.

The difference between the suction dehydration rate on one surface of the sheet and the suction dehydration rate on the other surface is preferably 10% or less of the suction dehydration rate on the other surface. That is, in the method for producing a glass sheet slip sheet of the present invention, it is preferable that suction from both sides of the sheet is performed with substantially the same suction force.

The sheet forming step and the wet paper web preparation step may be performed separately using separate devices, but may be performed continuously or partially overlapping in the same device. For example, in the wire part of a paper machine, the wet paper may be formed by dewatering while placing the slurry on a wire (net) to form a sheet.

In the drying step, the interleaf paper can be obtained by drying wet paper by a conventionally known method using a dryer roll or the like.

In order to further remove the short fibers having a fiber length of 200 μm or less that can remain on the surface of the slip sheet, in the method for producing the slip sheet for glass plate of the present invention, both sides of the slip sheet after the drying step are further sucked. It is preferable to include an additional suction step.

Note that calendering, super calendering, soft nip calendering, embossing, and the like may be performed during and / or after papermaking of the glass sheet interleaf. Surface properties and thickness can be adjusted by processing.

The glass sheet slip sheet of the first aspect of the present invention can be efficiently manufactured by the manufacturing method of the second aspect of the present invention.

The glass sheet slip sheet of the present invention is used by being inserted between the glass sheets. For example, the glass sheet interleaving paper is typically inserted one by one between a plurality of glass sheets to form a laminated body as a whole, and the laminated body is a target for storage and transportation. Moreover, you may package a glass plate single-piece | unit or the said laminated body using the slip sheet for glass plates of this invention. Therefore, this invention has the side surface of the protection method of a glass plate including the process of arrange | positioning (especially inserting) the said paper for glass plates between glass plates.

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

In particular, the size and weight of a glass plate for a flat panel display have increased with the increase in the size of the display. However, the slip sheet for a glass plate of the present invention has the surface of such a large or heavy glass plate. It can be well protected. In particular, the interleaving paper for a glass plate of the present invention has a very small content of fine foreign matters, particularly hydrophobic foreign matters such as talc adsorbing silicone, pitch, resin, rubber, oil (excluding silicone) and hydrophobic foreign matters. Since there are few, even if it presses with a heavy glass plate, it will suppress thru | or avoid that the said foreign material transfers to a glass plate. Therefore, the interleaving paper for a glass plate of the present invention can be suitably used for a glass plate for a flat panel display in which surface cleanliness is particularly required.

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

[Measurement of short fiber content]
A Kajaani fiber length measuring instrument “Metso Fiber image analyzer FS5” (manufactured by Metso Automation) was used as a fiber length measuring method by an optical automatic analysis method defined in JIS P8226 (2006).

[Abundance of short fibers on the paper surface]
The interleaf paper for glass plate was cut into 20 cm × 20 cm, and only one side of the paper was sufficiently washed with demetalized ion water to drop the short fibers. The liquid after washing was collected, and the fiber length of each fiber in the liquid was measured with the Kajaani fiber length measuring device “Metso Fiber image analyzer FS5”. The number of fiber lengths of 200 μm or less was counted to determine the ratio of the short fibers per unit area.

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

[Example 1]
100 parts by weight of softwood bleached kraft pulp was prepared and after beating, the beating degree was 550 ml c. s. f. A slurry prepared as above was obtained. As a paper strength enhancer, 0.2 part by mass of polyacrylamide (trade name: Polystron 1250, manufactured by Arakawa Chemical Industry Co., Ltd.) was added to the total pulp mass to prepare a pulp slurry having a concentration of 0.4% by weight. This was paper-made using a long web paper machine equipped with an on-top former in the wire part to obtain a slip sheet for a glass plate having a basis weight of 55 g / m ² . The wire part uses 76 mesh plain woven plastic wire, and the difference in the dewatering rate of the on-top former on both sides of the wet paper (based on the dewatering rate of the upper on-top former) is 7% or more and 10% or less It adjusted so that it might become.

[Example 2]
A basis weight of 55 g / in the same manner as in Example 1 except that the difference in the dewatering rate of the on-top former on both sides of the wet paper was adjusted to 5% or less (based on the dewatering rate of the upper on-top former). An m ² slip sheet for glass plate was obtained.

[Comparative Example 1]
A glass sheet slip with a basis weight of 55 g / m ² was obtained in the same manner as in Example 1 except that the on-top former was not used.

Table 1 shows the measurement results of the glass sheets for the examples and comparative examples. Moreover, when the transfer to the glass plate of the interleaving paper for the glass plate obtained in Examples and Comparative Examples was confirmed by a transport test, the liquid crystal panel was formed using the glass plate using the interleaving paper of the example. No disconnection of the color film was observed. On the other hand, disconnection of the color film was observed during the formation of an array of a liquid crystal panel using a glass plate using the interleaving paper for glass plate of Comparative Example 1.

Claims

It is a slip sheet for glass plate made from wood pulp,
A slip sheet for glass plate in which the content of short fibers having a fiber length of 200 μm or less is 10.5% by weight or less.
The glass sheet slip sheet according to claim 1, wherein the content of the short fibers is 1.2% by weight or more.
3. The glass sheet interleaf according to claim 1, wherein an average fiber diameter of the short fibers is 10 to 50 μm.
The slip sheet for glass plate according to claim 1 or 2, wherein the amount of the short fibers on the surface is 300 to 850 fibers / m 2 .
The difference between the abundance of the short fibers on one surface and the abundance of the short fibers on the other surface is 15% or less of the abundance of the short fibers on the other surface. Slip sheet for glass plate.
3. The glass sheet interleaf according to claim 1, wherein the thickness is 20 to 200 μm.
The interleaving paper for a glass plate according to claim 1 or 2, wherein the mean deviation (MMD) of the friction coefficient of the surface by the KES method is 0.022 or less.
The glass sheet slip sheet according to claim 1 or 2, wherein the glass sheet is for display.
The slip sheet for glass plates according to claim 8, wherein the display is a TFT liquid crystal display or an organic EL display.
A laminate comprising the glass sheet interleaving paper according to any one of claims 1 to 9 and a glass sheet.
A method for protecting a glass plate, comprising a step of arranging the interleaving paper for a glass plate according to any one of claims 1 to 9 between the glass plates.
A method for producing a glass sheet interleaving paper according to any one of claims 1 to 9,
A slurry preparation step for preparing a wood pulp slurry;
A sheet forming step for forming the slurry into a sheet;
A wet paper web preparation step for dehydrating the sheet to form a wet paper web;
Including at least a drying step of drying the wet paper to obtain the slip sheet;
A manufacturing method in which dehydration is performed from both sides of the sheet in the wet paper preparation step.
The manufacturing method according to claim 12, wherein the dehydration is performed by suction.
The manufacturing method according to claim 13, wherein a difference between the suction dewatering rate on one surface of the sheet and the suction dewatering rate on the other surface is 10% or less of the suction dewatering rate on the other surface. .
The manufacturing method according to claim 13 or 14, further comprising an additional suction step of sucking both surfaces of the interleaving paper after the drying step.