CN114537883A

CN114537883A - Interleaving paper for glass plate, glass plate laminate, and glass plate package

Info

Publication number: CN114537883A
Application number: CN202111405716.6A
Authority: CN
Inventors: 嶋村刚直; 阿部真之; 细野惠嗣; 石田涉
Original assignee: Asahi Glass Co Ltd
Current assignee: AGC Inc
Priority date: 2020-11-25
Filing date: 2021-11-24
Publication date: 2022-05-27
Also published as: TW202220909A; KR20220072780A

Abstract

The present invention relates to a lining paper for glass plates, a glass plate laminate and a glass plate package, wherein the lining paper for glass plates is characterized in that the thickness is 30 to 150 [ mu ] m, the smoothness of at least one main surface of the lining paper for glass plates is more than 20 seconds, and the compression elastic modulus K is 1.0 to 8.5 MPa.

Description

Interleaving paper for glass plate, glass plate laminate, and glass plate package

Technical Field

The present invention relates to a lining paper for glass sheets, a glass sheet laminate, and a glass sheet package.

Background

For example, in a glass plate used for a flat panel Display such as an LCD (Liquid Crystal Display) and an OLED (Organic Light-Emitting Diode), since a fine electronic component is formed on the surface of the glass plate, a slight scratch or dirt on the surface causes a defect such as disconnection. Therefore, high cleanliness is required for the surface of the glass sheet.

The glass sheets are conveyed in a state where a plurality of glass sheets are stacked for the purpose of improving conveyance efficiency. In this case, a sheet of interleaving paper for glass sheets (hereinafter also referred to as "interleaving paper") is interposed between the glass sheets to prevent the surface of the glass sheets from being scratched during conveyance.

However, since the glass plates are laminated in a state where the surfaces thereof are pressed against the interleaving paper, there is a concern that: particles such as paper dust and foreign matter generated from the lining paper adhere to the surface of the glass plate, or scratches are generated on the surface of the glass plate mainly due to inorganic foreign matter in the lining paper. Therefore, there is a need for a sheet interleaving paper for glass sheets, which is less likely to cause particles to adhere to the surface of a glass sheet and can suppress scratches from occurring in the glass sheet.

Patent document 1 discloses a slip sheet for glass plates having a cured portion and a non-cured portion, and aims to suppress the generation of particles by setting the smoothness of the cured portion to 20 seconds or more. In patent document 2, it is desired to reduce scratches on a glass plate by setting the smoothness to 70 seconds or more.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2016-34843

Patent document 2: japanese patent laid-open publication No. 2016-35125

Disclosure of Invention

However, with the recent high definition of displays, the width and pitch of the wiring formed on the surface of the glass plate are finer than those of the conventional ones, and the quality required for the surface of the glass plate is higher. Therefore, even when the interleaving paper for glass sheets of patent documents 1 and 2 is used, for example, the following problems occur: it is necessary to improve the quality of the interleaving paper for glass sheets because the adhesion of particles to the glass sheets and the occurrence of scratches on the surfaces of the glass sheets cause disconnection of wiring on the glass sheets.

Therefore, in addition to the above-mentioned conventional techniques, many interleaving papers for glass sheets have been proposed which suppress the occurrence of scratches on the surface of the glass sheets. An example thereof is a slip sheet for glass plates, which is disclosed in Japanese patent laid-open publication No. 2016-006240 and has a limited content of minerals having a predetermined Mohs hardness or higher.

However, in the case of a glass plate used for a high-definition display, there is a problem that even if a backing paper containing only foreign matter having a predetermined mohs hardness or less is used. As a result of intensive studies, the inventors have found that even when only foreign matter having a mohs hardness of a predetermined value or less is present, the foreign matter may cause scratches on the glass sheet because of its high particle strength.

The purpose of the present invention is to provide a sheet for interleaving glass plates, which can reduce the adhesion of particles to the glass plates and suppress the occurrence of scratches on the surfaces of the glass plates, in accordance with the high definition of displays.

(1) The slip sheet for glass sheets of the present invention has a thickness of 30 to 150 [ mu ] m, and is characterized in that the slip sheet for glass sheets has a smoothness of at least one main surface of 20 seconds or more and a compressive modulus of elasticity K measured on the main surface of 1.0 to 8.5 MPa.

(2) The interleaving paper for glass sheets according to (1), wherein the arithmetic average height Sa of the main surface is 2.5 μm or more.

(3) The interleaving paper for glass plates according to (1) or (2), wherein the maximum height Sz of the main surface is 45 μm or more.

(4) The interleaving paper for glass plates according to any one of (1) to (3), wherein the density of the interleaving paper for glass plates is 0.4 (g/cm)³)～1.6(g/cm³) The smoothness of the main surface is 20 to 400 seconds.

(5) The interleaving paper for glass plates as described in any one of (1) to (4), wherein the sheet resistance of the interleaving paper for glass plates is 5.0X 10¹⁰(Ω/□)～5.0×10¹³(Ω/□)。

(6) The interleaving paper for glass plates according to any one of (1) to (5), wherein the compressive elastic modulus K (MPa) is equal to the number of foreign matters contained in the interleaving paper for glass plates, the foreign matters having an average diameter of 10 to 50 μm and a particle strength C of 15(MPa) or moreQuantity N (pieces/m)²) The hard foreign matter resistance value KN which is a product of (A) is 35.0 or less.

(7) The interleaving paper for glass plates as described in any one of (1) to (6), wherein the compressive elastic modulus K (MPa) and the number N (pieces/m) of foreign matters contained in the interleaving paper for glass plates, the foreign matters having an average diameter of 10 to 50 μm and a particle strength C of 15(MPa) or more²) The hard foreign matter resistance value KN which is the product of (A) is 15.0 or less.

(8) The interleaving paper for glass plates according to any one of (1) to (7), wherein the main surface is a surface in contact with an electronic circuit forming surface of the glass plate.

(9) A glass plate laminate comprising at least 2 glass plates laminated thereon, wherein the glass plate laminate comprises the interleaving paper for glass plates according to any one of (1) to (8) between the glass plates.

(10) A glass plate package comprising the glass plate laminate as set forth in (9) and a holder for placing the glass plate laminate.

According to the present invention, it is possible to provide an interleaving paper for glass plates, which can suppress the adhesion of particles to a glass plate and the occurrence of scratches on the surface of the glass plate, in accordance with the high definition of a display.

Drawings

FIG. 1 is a graph showing the relationship between Mohs hardness and particle strength.

FIG. 2 is a conceptual diagram illustrating an embodiment of a method for manufacturing a slip sheet for glass sheets.

FIG. 3 is a sectional view showing an embodiment of a carriage for placing a glass plate.

FIG. 4 is a sectional view showing one embodiment of the glass plate package body.

Description of the symbols

10 … glass plate package body,

12 … glass plate laminate

14 … glass plate

Slip sheet for 16 … glass plate

18 … tilting table

22 … base

24 … platform

30 … bracket

42 … roll of interleaving paper

100 … manufacturing installation of slip sheet for glass plate

112 … headbox

114 … mesh part

116 … go down the net

118 … surfing the Internet

120 … pressure part

124 … dryer section

126 … calendering section

128 … reel

130 … large roll

134 … cutter

136 … coil winder

Detailed Description

Hereinafter, preferred embodiments of the interleaving paper for glass sheets according to the present invention will be described. The embodiments described below are merely examples, and the present invention is not limited to these embodiments. Note that the glass plate is also expressed as a glass substrate.

From the viewpoint of conveyance efficiency, the glass sheets are conveyed in a state where at least 2 or more glass sheets are stacked and placed on a carriage. An article in which at least 2 or more glass sheets are stacked is referred to as a glass sheet stacked body, and an article in which the glass sheet stacked body is placed on a tray is referred to as a glass sheet package.

In the glass sheet laminate, if the glass sheets contact each other, scratches may be generated on the surfaces of the glass sheets. It is known that such a scratch on the electronic circuit formation surface of the glass plate causes a problem such as disconnection. Therefore, the glass plate interleaving paper is interposed between the glass plates, thereby preventing the electronic circuit forming surface of the glass plate from being scratched.

However, particles generated from the interleaving paper may adhere to the surface of the glass plate, or a scratch may be generated on the surface of the glass plate mainly due to inorganic foreign matters in the interleaving paper. With the recent high definition of displays, the width and pitch of wiring formed on the surface of a glass plate have been finer than those of conventional devices, and the quality required for the surface of a glass substrate has been increased. Therefore, even if the interleaving paper for glass plates, which has not been a problem in the past, is used, problems such as disconnection of wiring on the glass plates occur.

The present inventors have found that by making the smoothness of the interleaving paper constant or more, even in a high-definition display, defects due to the adhesion of particles can be suppressed. However, even when the smoothness of the interleaving paper is increased to reduce the amount of particles adhering to the interleaving paper, there is a case where scratches are generated on the surface of the glass plate, which is a problem. Therefore, it is required to suppress the adhesion of particles and the occurrence of scratches on the surface of the glass sheet.

Therefore, the present inventors investigated scratches that cause defects such as disconnection. As a result, it was found that the foreign matter had an average diameter of 10 μm or more and a particle strength C of 15(MPa) or more. Among them, scratches caused by foreign matter having an average diameter of 10 to 50 μm and a particle strength C of 15(MPa) or more are not problematic in many cases. However, as the display is made more sophisticated, the quality required for the surface of the glass substrate increases, and as a result, it is considered that scratches caused by these foreign substances also become a problem.

It is considered that foreign matter having an average diameter of less than 10 μm is likely to be buried in the interleaving paper for glass sheets, and thus is unlikely to cause scratching of the glass sheets. Further, if the foreign matter has a particle strength C of less than 15(MPa), it is considered that the foreign matter is not easily scratched even if it is pressed into the glass plate. Further, even when a scratch occurs, the size is small, and therefore, it is considered that a disconnection failure or the like is not likely to occur. Therefore, it is important to produce a backing paper in which the amount of foreign matter contained in the backing paper is controlled so as to reduce the particle size of the foreign matter having an average diameter of 10 to 50 μm and a particle strength C of 15(MPa) or more.

The foreign matter in the interleaving paper is pulp as a raw material of the interleaving paper; dust generated by the interleaving paper manufacturing apparatus; water used in the production process of the interleaving paper contains impurities, and is mixed into the interleaving paper without being removed by a filter or the like. In addition, substances added as additives in the process of producing interleaving paper for glass sheets other than interleaving paper for glass sheets remain in the piping, the roller surface that comes into contact during paper feeding, and the like, and foreign matter is mixed in during the production of interleaving paper for glass sheets due to the reason that the foreign matter adheres to the surface of the interleaving paper, and the foreign matter having a particle strength C of 15(MPa) or more may be present in the mixed foreign matter. Therefore, it is difficult to completely eliminate foreign matter having an average diameter of 10 to 50 μm and a particle strength C of 15(MPa) or more.

Therefore, the inventors focused on cushioning properties of the mount. The cushioning property of the interleaving paper is defined by a compressive elastic modulus k (mpa) in the thickness direction of the interleaving paper. A smaller value of the compressive modulus of elasticity K (MPa) means a higher cushion property, and a larger value means a lower cushion property. As a result of intensive studies, the inventors have found that even when foreign matter having an average diameter of 10 to 50 μm and a particle strength C of 15(MPa) or more is mixed into the interleaving paper having a higher cushioning property, scratching can be suppressed.

This is considered to be because, when glass sheets are laminated, the higher the cushioning property of the interleaving paper, the more easily foreign matter is buried in the interleaving paper, and therefore, the scratch due to the foreign matter having an average diameter of 10 to 50 μm and a particle strength C of 15(MPa) or more is reduced.

(raw material pulp)

The kind of the raw material pulp is not particularly limited, and pulp having characteristics required as the liner paper can be suitably used. Examples thereof include chemical pulps such as Kraft Pulp (KP), Sulfite Pulp (SP), and Alkali Pulp (AP); mechanical pulps such as wood pulp (GP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP); semichemical pulp such as Chemical Ground Pulp (CGP) and semichemical pulp (SCP) as the intermediate mechanical/chemical pulp; non-wood fiber paper pulp taking kenaf, daphne giraldii, paper mulberry, wild goose skin, hemp and the like as raw materials; synthetic pulp, synthetic fiber, waste paper pulp (DIP), and the like. The pulp may be bleached or unbleached, and examples thereof include bleached hardwood kraft pulp (LBKP), bleached softwood kraft pulp (NBKP), unbleached hardwood kraft pulp (LUKP), and unbleached softwood kraft pulp (NUKP). In addition, Carbon Nanofibers (CNF) may also be included. The raw material paper pulp can be waste paper pulp, also can be virgin pulp, and also can be a mixture of the waste paper pulp and the virgin pulp. In order to particularly suppress contamination and scratching of a glass plate due to particles and foreign matter,particularly, LBKP and NBKP subjected to bleaching treatment are preferable, and further, pulp subjected to foreign matter removal by a cyclone, a flotation machine, or the like is more preferable. The foreign matter in the pulp means a substance other than the fiber component contained in the pulp. There are cases where SiC or ZrO is mixed in the pulp₂、Al₂O₃、TiO₂、SiO₂、Fe、Fe₂O₃、Cr、Ni、CaF₂、MgO、CaCO₃And compounds such as Al and Cu and alloys thereof, aromatic polyether ketone (PEEK), polyphenylene sulfide (PPS), ultra high molecular weight polyethylene (UPE), and resins such as epoxy resin. It is considered that these are mixed from minerals and devices in the processes from the felling of trees to the pulping process by pulp chips.

(method of producing interleaving paper for glass plate)

A method for manufacturing a glass sheet interleaving paper will be described with reference to a conceptual diagram showing an embodiment of a method for manufacturing a glass sheet interleaving paper shown in fig. 2.

In the apparatus 100 for manufacturing a glass sheet interleaving paper, a raw material slurry (a slurry-like liquid obtained by diluting and dissociating pulp with water) of the glass sheet interleaving paper is beaten and then fed from a head box 112 in a sheet-like manner onto a lower wire 116 provided in a wire part 114. The raw material slurry supplied to the lower wire 116 is then sandwiched between the lower wire 116 and the upper wire 118, thereby being spread to a uniform thickness and dewatered to become a wet paper (paper).

The lower web 116 and the upper web 118 of the web portion 114 are permeable films formed in an annular band shape. Specifically, the endless belt is a net made of a plastic or metal material, or a felt made of natural fibers or synthetic fibers.

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

The wet paper formed by the wire part 114 is transferred to a press roll, an endless belt-shaped felt, and a press part 120 having a press roll pair, etc., where further dewatering and pressing are performed.

The wet paper having passed through the press section 120 is conveyed to a dryer section 124 composed of a plurality of rolls, and dried in an atmosphere of, for example, about 120 ℃.

When the wet paper is directly conveyed at a high speed by the dryer section 124, the wet paper may be conveyed in a state where an auxiliary member called a canvas is brought into contact with the wet paper because paper dust may be generated.

The paper dried by the dryer section 124 is conveyed to a rolling section 126, and a predetermined linear pressure is applied to the paper by nip conveyance by a rolling roller or the like, thereby smoothing the front and back surfaces. In the rolling treatment, various kinds of rolling such as soft rolling, hard rolling, super rolling, and hot rolling may be used, and the rolling treatment is not limited to on-line rolling, and may be used off-line. In addition, multi-stage compression may be used. If necessary, a coating machine unit may be provided between the dryer unit 124 and the rolling unit 126 to coat the surface of the smoothed paper with a coating material or the like.

The paper rolled in the rolling section 126 is wound as a glass sheet backing paper on a reel 128 and rolled into a roll shape (hereinafter referred to as a large roll 130).

The glass sheet lining paper to be formed into the large roll 130 is generally cut into pieces corresponding to the width of the product, and wound up to form a roll 42 on which a long glass sheet lining paper having a predetermined length of about 8000m to 10000m is wound.

The glass sheet lining paper is fed from the large roll 130, cut into a predetermined width (cut in the longitudinal direction) by a cutter 134, and wound by a winder 136. When the glass sheet interleaving paper fed from the large roll 130 has a predetermined length, the glass sheet interleaving paper is cut into a predetermined length (cut in the width direction) by the cutter 134, and a long interleaving paper roll 42 in which the glass sheet interleaving paper is wound in a predetermined width is produced.

The long glass plate interleaving paper wound around the interleaving paper roll 42 is cut into a cut sheet shape (rectangular shape) having a size corresponding to the stacked glass plates, and is interposed between the stacked glass plates.

(thickness of interleaving paper)

The thickness of the interleaving paper may be in accordance with JIS P8118: 2014 is measured by the paper thickness measurement. The measurement can be carried out, for example, using an automatic lifting/lowering paper thickness meter (manufactured by bear-grain processor, TM-600).

Here, if the interleaving paper is too thin, even if the cushioning property of the interleaving paper is high, the foreign matter is not buried in the interleaving paper, and therefore, the interleaving paper is easily scratched. Further, since the strength of the interleaving paper is weakened, defects such as paper dust are likely to occur during the production of the interleaving paper, and the production efficiency is lowered. Therefore, the thickness of the interleaving paper for glass sheets of the present invention is 30 μm or more, preferably 40 μm or more, more preferably 50 μm or more, and still more preferably 60 μm or more. Further, if the interleaving paper is too thick, the volume and weight of the interleaving paper increase, and therefore the number of glass sheets that can be stacked on the pallet decreases. Therefore, the thickness of the interleaving paper for glass sheets of the present invention is 150 μm or less, preferably 140 μm or less, more preferably 130 μm or less, and still more preferably 120 μm or less.

(modulus of elasticity under compression)

The slip sheet for glass sheets of the present invention has a compressive modulus of elasticity K (MPa) of 1.0 to 8.5 MPa. Since the cushioning property of the interleaving paper is higher as the compression elastic modulus K is smaller, scratches due to foreign matters having an average diameter of 10 to 50 μm and a particle strength C of 15(MPa) or more can be suppressed. Here, among the glass plates, it is particularly required to suppress particle adhesion and scratching that are the electronic circuit forming surfaces. Therefore, if the compressive modulus k (mpa) of the portion of the interleaving paper in contact with the glass plate on the main surface of the interleaving paper in contact with the electronic circuit forming surface is within the above range, the effects of the present invention can be exhibited. The compressive modulus of elasticity K (MPa) is more preferably 8.0MPa or less, still more preferably 5.0MPa or less, particularly preferably 3.0MPa or less, and most preferably 2.0MPa or less. The lower limit of the compression elastic modulus of the interleaving paper is 1.0MPa or more. If the compressive modulus of elasticity of the interleaving paper is not less than the above lower limit, the durability can be expected to be improved. In the present specification, the compressive modulus of elasticity k (mpa) of the interleaving paper for glass sheets is measured by the following method.

(method of measuring compression modulus of elasticity)

The modulus of elasticity in compression of the backing paper can be measured, for example, by using a constant pressure thickness measuring instrument (PG-02J, manufactured by TECCLOCK). A load corresponding to a pressure P1(kPa) was applied to the substantially center of the interleaving paperThe sheet thickness at the section was T1(μm), and the sheet thickness at the time when a load corresponding to a pressure P2(kPa) was applied to the substantially central section of the interleaving paper was T2, and (strain amount) ═ T1-T2/T1 (dimensionless) was calculated. Then, the (compressive modulus of elasticity) — (P2-P1)/(strain amount × 10) was obtained^－3) (MPa). In the present specification, P1 is 100(kPa), and P2 is 270 (kPa).

The compression elastic modulus K of the interleaving paper can be mainly controlled by the apparent density of the interleaving paper and the density of the outermost layer. The apparent density is the density as one piece of paper. Generally, the thickness of the paper is increased as the weight per unit area is increased, but the density is decreased as the weight per unit area of the base paper is decreased and the thickness is increased, and the compression elastic modulus K is decreased, that is, the cushioning property tends to be increased. As a method for thickening the mount paper at the same basis weight, the content of conifer pulp having a large proportion of long fibers in the raw material can be increased; the pulping amount is adjusted, and the freeness of the raw material paper pulp is improved; adding a swelling agent, and the like. In order to prevent the glass plate from being contaminated, the amount of the reagent such as the swelling agent to be added is preferably small.

The density of the outermost layer is controlled by the pressure applied to the paper by the calender roll (hereinafter, referred to as "nip pressure") in the calender section. That is, when the slip sheet is nipped and conveyed by the rolling unit 126, the smaller the nip pressure is, the smaller the compression elastic modulus is, and the slip sheet with high cushioning property can be obtained. However, this operation is directed to reduce the adhesion between fibers, and may cause an increase in the size of particles generated from the interleaving paper. Therefore, it is preferable to reduce the apparent density of the interleaving paper, while hardening the surface thereof to provide the interleaving paper having cushioning properties as a whole. The compression elastic modulus K may not necessarily be equal to the apparent density, but this is also influenced by the density of the outermost layer, and therefore, it is estimated that the difference in density in the paper layer direction of the interleaving paper is more likely to occur, and the compression elastic modulus K is more likely to deviate from the apparent density.

By increasing the temperature of the surface of the heat roller, the nip pressure, prolonging the contact time, increasing the number of nips, etc. in the hot calendering process, highly smooth paper can be obtained. On the other hand, an increase in the nip pressure, the contact time, and the number of times decreases the bulkiness. Here, since the temperature gradient in the thickness direction of the paper web is increased by applying a temperature higher than the temperature of the paper web to the heat roller, the plastic deformation of the surface of the paper layer is promoted, and the plastic deformation of the inside of the paper layer becomes difficult, when the heat roller is heated to a high temperature, fluffy cushioning lining paper is easily produced, and this is suitable for the present invention. For the same reason, it is more preferable to lower the temperature of the paper web before the rolling treatment to further increase the temperature gradient. Examples of the cooling method include a method using air, water, and a cooling roll. In the case where a small amount of water is applied to the paper web, immediately dried by low-temperature dry blowing, and subjected to rolling treatment after cooling the paper web by taking off the heat of evaporation, rolling treatment with a large temperature gradient can be performed before the water penetrates into the capillaries in the paper layer, and therefore, plastic deformation and fluffing in the paper layer can be suppressed, which is particularly preferable. By allowing the water to act for a very short time, the treatment can be performed without causing coarsening accompanied by breakage of the bonds between the fibers or deformation of the fibers.

In addition, it is known that in hot soft rolling, there is a difference in the degree of smoothness increase between paper on the metal hot roll side and paper on the resin elastic roll side. Such a treatment can particularly improve the smoothness of one surface, and is therefore suitable for obtaining a slip sheet having a highly smooth slip sheet surface and a low density as the entire slip sheet. In one embodiment of the present invention, the temperature suitable for obtaining highly smooth paper is 25 to 250 ℃. The higher the temperature, the higher the smoothing effect, but if it exceeds 250 deg.C, the paper color change (the input device ヤケ) and the smoothing in the width direction become uneven, and the deterioration of the elastic roller is accelerated. The smoothing can be performed even at less than 100 ℃, but the smoothing by the above-described temperature gradient is insufficient, and therefore, particularly when the slip sheet having a smoothness exceeding 100 seconds is obtained, 100 ℃ or more is preferable.

In one embodiment of the present invention, the nip pressure suitable for obtaining highly smooth paper is, for example, 5 to 350 kN/m. When the nip pressure is less than 5kN/m, the smoothing is insufficient, and when it exceeds 350kN/m, the elastic roller is likely to be deteriorated. In addition, as a method for exhibiting the same effect, it is possible to join papers having a plurality of densities.

By designing the type of rolling treatment, the temperature and the nip pressure in the rolling treatment, and the like in this manner, a backing paper having a high surface smoothness and a small compressive elastic modulus can be obtained.

(smoothness)

The smoothness of at least one main surface of the interleaving paper for glass sheets of the present invention is 20 seconds or more. The smoothness of the backing paper indicates unevenness including unevenness of the surface of the backing paper having a height of several μm to several mm and unevenness of fibers below the unevenness, and the smoothness is high by adhering the fibers to each other.

Namely, the gaps between the fibers can be eliminated by using the pulp with short fiber length; the beating is enhanced to enhance the winding of the fibers; reducing the surface roughness of the drying cylinder in the drying process; the cleanliness is improved; controlling the papermaking speed and the humidification/dehumidification environment to perform papermaking while performing humidity conditioning; and increasing the nip pressure of the rolling treatment. The higher the smoothness, the more the fibers and the foreign matter adhere to each other, and therefore, the generation of particles such as paper dust and foreign matter from the paper surface is suppressed.

In the case where the smoothness is increased by subjecting the interleaving paper to the rolling process at a high nip pressure, the interleaving paper is crushed, and therefore, the compression elastic modulus K tends to become large. However, when the smoothness of the interleaving paper is less than 20 seconds, particles are easily generated. Therefore, by designing not only the nip pressure but also the type of rolling treatment, the temperature during the rolling treatment, and the like as described above, the smoothness can be set to 20 seconds or more and the compressive modulus of elasticity K can be set to 1.0Mpa to 8.5Mpa, and both the suppression of particles and the suppression of scratches can be achieved.

Here, the electronic circuit forming surface of the glass plate is particularly required to suppress contamination, that is, to suppress the adhesion of particles. Therefore, if the smoothness of the portion of the main surface of the mount paper that is in contact with the electronic circuit forming surface and that is in contact with the glass plate is 20 seconds or more, the effects of the present invention can be exhibited.

However, if the smoothness is too high, the adhesion of the interleaving paper increases, and sticking to the glass plate or the conveyance roller occurs due to static electricity. Therefore, for example, when a glass plate or an interleaving paper is taken out from a glass plate laminate (hereinafter, also referred to as "unpacking"), a problem that the interleaving paper sticks to the glass plate is likely to occur. Therefore, the smoothness of the surface of the interleaving paper is preferably 400 seconds or less, more preferably 100 seconds or less, further preferably 70 seconds or less, and particularly preferably 50 seconds or less. If the smoothness of the surface of the interleaving paper is not more than the upper limit, the occurrence of troubles such as the interleaving paper sticking to the glass plate during unpacking can be reduced.

In the present specification, smoothness is measured by the measurement method described in the examples described below.

The measurement position of the smoothness is not particularly limited as long as the measurement is performed at a position of the backing paper that can contact the glass plate, and the measurement is performed at, for example, a substantially central portion of the backing paper.

(sheet resistance (omega/□))

As a result of intensive studies, the present inventors have found that the sticking of the interleaving paper and the substrate is related to the charging property of the interleaving paper. The charging property of the interleaving paper can be represented by sheet resistance (surface resistivity) of the interleaving paper. Sheet resistance represents the unit area (1 cm) of a film such as paper or film²) The resistance value of (2). The higher the sheet resistance, the lower the conductivity, and the easier the charging. The sheet resistance is mainly affected by the moisture content of the interleaving paper, but even with the same moisture content, the conductive properties differ depending on the state of the fibers such as the thickness, the winding form, and the orientation of the fibers, the components contained therein, the thickness of the interleaving paper, and the value of the sheet resistance can be controlled by the combination thereof. The more the moisture content, the denser the fiber, and the smaller the sheet resistance becomes. In addition, in order to reduce the sheet resistance, an antistatic agent may be added within a range that does not degrade the quality of the interleaving paper. The sheet resistance can be measured, for example, by using Hiresta-UX MCP-HT 800 (manufactured by Mitsubishi chemical analysis technology).

The sheet resistance of the interleaving paper for glass sheets of the present invention is 5.0X 10¹³Omega/□ or less, the occurrence of the above-mentioned trouble such as the interleaving paper sticking to the glass plate can be reduced. Therefore, the sheet resistance of the interleaving paper is preferably 5.0 × 10¹³Omega/□ or less, preferablyIs selected to be 2.5 × 10¹³Omega/□ or less, more preferably 1.0X 10¹³Omega/□ or less. If the sheet resistance of the interleaving paper is not more than the upper limit, the occurrence of troubles such as the interleaving paper sticking to the glass plate at the time of unpacking can be further reduced.

When the sheet resistance of the interleaving paper is too low, the interleaving paper does not sufficiently adhere to the glass plate when the vertical tray is loaded with the interleaving paper, and a problem such as peeling of the interleaving paper may occur. Further, when the sheet resistance of the interleaving paper is intended to be reduced to increase the water holding amount of the interleaving paper, a problem may occur in that the interleaving paper and the glass are excessively adhered via moisture. Therefore, the sheet resistance of the interleaving paper for glass sheets of the present invention is preferably 5.0X 10¹⁰Omega/□ or more, more preferably 7.5X 10¹⁰Omega/□ or more, more preferably 1.0X 10¹¹Omega/□ or more. If the sheet resistance of the interleaving paper is not less than the lower limit, the occurrence of troubles such as peeling of the interleaving paper and excessive sticking can be reduced.

(hard foreign matter resistance value)

The hard foreign matter resistance value is determined by the compression elastic modulus K (MPa) and the number N (number/m) of foreign matters with the average diameter of 10-50 μm and the particle strength C of 15(MPa) or more contained in the lining paper²) The product KN of.

The more the hard interleaving paper having the foreign matter resistance value KN is, the less the foreign matter having an average diameter of 10 to 50 μm and a particle strength C of 15(MPa) or more, which causes the scratch, or the smaller the compressive elastic modulus K, the more the scratch generated on the glass plate can be reduced. The hard foreign matter resistance value is preferably 35.0 or less, more preferably 30.0 or less, further preferably 15.0 or less, particularly preferably 10.0 or less, and most preferably 5.0 or less. If the hard foreign matter resistance value KN is to be reduced, it is necessary to suppress the mixing of foreign matter in the manufacturing process, which increases the manufacturing cost. Therefore, the lower limit value of the hard foreign matter resistance value KN is preferably 0.1 or more, and more preferably 0.5 or more.

(foreign matter having an average diameter of 10 to 50 μm and a particle strength C of 15(MPa) or more)

In the present specification, the particle strength is used as the evaluation of the foreign matter. As an evaluation of foreign matter in the interleaving paper other than the particle strength, for example, there is a method of performing an evaluation using mohs hardness, such as japanese patent application laid-open No. 2016-006240. Mohs' hardness, defined as "which scratch an object when scratched with another object," is a measure of the hardness of bulk minerals in general in comparison to each other. Further, since the mohs hardness is a relative value, even if the mohs hardness is the same, the hardness (particle strength) is not necessarily the same, and it is impossible to quantitatively express which one is more likely to cause a scratch.

The inventors investigated the relationship between particle strength and mohs hardness, and the results are shown in table 1. Fig. 1 is a graph showing the results of measuring the particle strength of a plurality of particles for various components of minerals generally known in mohs hardness, which are considered to be fine foreign matter in lining paper. FIG. 1 is a box plot showing a first quartile, a second quartile, a third quartile, a maximum value, a minimum value, an arithmetic mean, and an outlier.

The outlier refers to data larger than the number obtained by adding a value obtained by multiplying the quartile range (the difference between the third quartile and the first quartile) by 1.5 times to the third quartile, or data smaller than the number obtained by subtracting a value obtained by multiplying the quartile range by 1.5 times from the first quartile.

The maximum value is the largest value among data other than the outlier. The minimum value is the smallest value among data other than the outlier. In the box plot of fig. 1, outliers are represented by white circles and arithmetic averages are represented by black circles.

The inventors found that the particle strength of the fine foreign matter is approximately in the order of the mohs hardness as shown in fig. 1, but the particle strength is not always uniform, and the following may occur: the value of the mohs hardness and the value of the particle strength are reversed, and the variation in the particle strength is large even for the same kind of particles.

These are presumed to be caused by the following cases: the mode of generation differs for each particle; the density and the orientation state of the crystallites are different; presence of voids, etc. Therefore, even when only foreign matter having a specific mohs hardness or less is present, the glass sheet may be scratched due to the high particle strength of the foreign matter.

In such a case, even if there is no problem with a conventional glass plate for a display, there is a possibility that the problem will be caused with a glass plate used for a high-definition display. From the above studies, it is considered that the hardness of the fine foreign matter causing the scratch on the glass plate is preferably expressed by the particle strength as compared with the representative value based on the mohs hardness.

The length and length of the outer shape of the foreign matter are measured by observing the foreign matter present on the surface of the backing paper from the thickness direction of the backing paper, and the average diameter of the foreign matter is the sum average of the measured length and length. Examples of the foreign matter having a particle strength C of 15MPa or more include SiC and ZrO₂、Al₂O₃、TiO₂、SiO₂、Fe、Fe₂O₃、Cr、Ni、CaF₂、MgO、CaCO₃Compounds such as Al and Cu and alloys thereof, PEEK, PPS, UPE, and resins such as epoxy resin, but the particle strength varies even with the same composition, and therefore, the particle strength needs to be measured even for the foreign matter.

The number N (number/m) of foreign matters having an average diameter of 10 to 50 [ mu ] m and a particle strength C of 15(MPa) or more in the backing paper is reduced²) The method (4) includes a method of using a pulp having a small foreign matter content; a method of removing a magnetic substance by a magnetic filter; a method of removing fine ore and dust from pulp by applying centrifugal force; a method of removing foreign matter by adsorbing the foreign matter to fine bubbles using a flotation device. A method of removing foreign matter contained in raw material water by filtration or the like; the number of the foreign matters N (number/m) can be reduced by performing a paper making process in a clean room in the paper making process to prevent dust from entering the clean room²). As a method of using pulp with a small foreign matter content, there is a method of selecting pulp with a small ash content and pulp with a small amount of inorganic elements as measured by fluorescent X-ray.

Number of foreign matters N (pieces/m)²) Preferably 10.0 or less, more preferably 5.0 or less, further preferably 1.0 or less, particularly preferably 0.1 or less, and most preferably 0.01 or less. Number of foreign matters N (pieces/m)²) The lower limit of (B) is not particularly limited, and is, for example, 1.0X 10^－6As described above. Even if the above-described countermeasure for preventing the inclusion of foreign matter is taken, it is difficult to completely eliminate the foreign matter having an average diameter of 10 to 50 μm and a particle strength C of 15(MPa) or more.

Number of foreign matters N (pieces/m)²) The measurement can be performed by the following method using a micro compression tester. For example, the measurement was carried out by a laser microscope (VK-8500, manufactured by Keyence) and a micro compression tester (MCT-510, manufactured by Shimadzu corporation). Mount sheets on the table, and measure 1600 areas for 1 field of view, for example, 2mm × 1.4 mm. In this case, the measurement may be performed automatically by moving the measurement 1 field at a time using the teaching function of the microscope and measuring the next field. Next, the size of each foreign matter in the measurement region is calculated from the number of pixels, and particles having an average diameter of 10 to 50 μm are selected. The foreign matter is placed on a table of a micro compression tester to measure the particle strength C one by one, particles having a particle strength C of 15(MPa) or more are counted, and the number of particles is converted into the number per 1m²The number of foreign bodies present N (pieces/m)²) To be measured.

The particle strength C used here is not limited to the strength measured by a micro compression tester, and may be, for example, the hardness of a particle estimated from the depth of indentation using a nanoindenter or the hardness of a particle measured by a micro vickers hardness tester.

(arithmetic mean height Sa (. mu.m))

The arithmetic average height Sa is a parameter for extending the arithmetic average height Ra of the line to the surface, and represents the average of the absolute values of the differences between the average of the heights of the surface of the interleaving paper and the heights of the points. The arithmetic average height Sa is generally used for evaluating surface roughness.

When the arithmetic average height Sa of the interleaving paper is large, the smoothness of the interleaving paper tends to be small. However, if the smoothness of the interleaving paper is less than 20 seconds, particles are easily generated. By setting the arithmetic average height Sa of the interleaving paper to a constant value or more and setting the smoothness to 20 seconds or more, both the suppression of particles and the suppression of scratches can be achieved.

Therefore, the smoothness of the interleaving paper is 20 seconds or more, and the arithmetic average height Sa of at least one main surface of the interleaving paper is preferably 2.5 μm or more, and more preferably 3.0 μm or more. If the arithmetic average height Sa of the interleaving paper is not less than the lower limit, foreign matter present in the interleaving paper is easily buried, and it is expected that scratching due to pressing of foreign matter is suppressed. The upper limit of the arithmetic average height Sa of the interleaving paper is preferably 8.0 μm or less, more preferably 6.0 μm or less, and further preferably 4.0 μm or less. If the arithmetic average height Sa is not more than the upper limit, generation of particles can be suppressed.

Here, the glass substrate is particularly required to be an electronic circuit forming surface for suppressing adhesion and scratching of particles. Therefore, the arithmetic mean height Sa of the principal surface on the side of the 2 principal surfaces of the interleaving paper which is in contact with the electronic circuit formation surface of the glass plate is particularly important.

Height information of 20 × 20 viewing fields and a total of 400 viewing fields is obtained at a 10mm pitch for 1 viewing field of 2.0mm × 1.4mm in an arbitrary area of the mount, and the arithmetic average height Sa is an average of arithmetic average heights of the respective viewing fields. The arithmetic mean height Sa can be measured by a known measuring instrument such as a laser microscope (VK-8500, Keyence).

(maximum height Sz (. mu.m))

The maximum height represents the distance from the highest point to the lowest point of the liner paper surface. Height information of 20 × 20 fields, for a total of 400 fields, is obtained at a 10mm pitch for 1 field of 2.0mm × 1.4mm area on the surface of the interleaving paper, and the maximum height Sz is an average of the maximum heights of the respective fields. The maximum height Sz can be measured by a known measuring instrument such as a laser microscope (VK-8500, manufactured by Keyence).

When the maximum height Sz of the base sheet is large, the smoothness of the base sheet tends to be small. However, if the smoothness of the interleaving paper is less than 20 seconds, particles are easily generated. By setting the maximum height Sz of the interleaving paper to be equal to or more than a certain value and setting the smoothness to be equal to or more than 20 seconds, both the suppression of particles and the suppression of scratches can be achieved.

Therefore, the smoothness of the interleaving paper is 20 seconds or more, and the maximum height Sz of at least one main surface of the interleaving paper is preferably 45 μm or more, and more preferably 50 μm or more. If the maximum height Sz of the interleaving paper is not less than the lower limit, foreign matter present in the interleaving paper is easily buried, and it is expected that scratching caused by pressing the foreign matter against the surface of the interleaving paper is suppressed. The upper limit of the maximum height Sz of the interleaving paper is preferably 80 μm or less, more preferably 65 μm or less, and still more preferably 54 μm or less. If the maximum height Sz is not more than the upper limit, the generation of particles can be suppressed.

Here, among the glass substrates, it is particularly required to suppress particle adhesion and scratching that are the electronic circuit forming surfaces. Therefore, the maximum height of the main surface of the slip sheet on the side contacting the electronic circuit forming surface of the glass plate is particularly important.

(Density of Lining paper)

The density of the lining paper is the weight per unit area (g/m) of the lining paper²) Divided by the paper thickness (. mu.m). The density of the interleaving paper is preferably 0.4 (g/cm)³) Above, more preferably 0.5 (g/cm)³) The above is more preferably 0.6 (g/cm)³) Above, 0.7 (g/cm) is particularly preferable³) As described above. If the density of the backing paper is not less than the lower limit, the backing paper having sufficient strength can be obtained, and thus, abnormalities such as paper dust are less likely to occur during the production process. Further, the density of the interleaving paper is preferably 1.6 (g/cm)³) Hereinafter, more preferably 1.4 (g/cm)³) Hereinafter, more preferably 1.2 (g/cm)³) The lower limit is particularly preferably 1.1 (g/cm)³) The following. If the density of the interleaving paper is not more than the upper limit, the amount of the raw material is small, and the productivity is high.

(glass plate laminate)

The glass sheet laminate of the present embodiment is formed by laminating at least 2 or more glass sheets, and the interleaving paper for glass sheets of the present invention is provided between the glass sheets.

(glass plate package body)

The glass plate package of the present embodiment includes a glass plate laminate on which at least 2 or more glass plates are laminated, and a carrier on which the glass plate laminate is placed, and the interleaving paper for glass plates of the present invention is provided between the glass plates.

FIG. 3 is a sectional view showing an embodiment of a carriage for placing a glass plate. FIG. 4 shows a cross-sectional view of one embodiment of a glass plate package.

The glass plate package 10 shown in fig. 4 has a glass plate laminate 12 and a bracket. The glass sheet laminate 12 has a glass sheet interleaving paper 16 between a glass sheet 14 and another glass sheet 14 adjacent thereto. The bracket 30 shown in fig. 3 is a known bracket for glass plate packing, and includes a base 22, an inclined table 18 provided on the upper surface of the base, and a mounting table 24. The angle θ between the mounting table 24 and the inclined table 18 is not particularly limited as long as the glass plate can be stably mounted, and is preferably 90 °.

The angle γ of the tilting table 18 is the angle of the tilting table 18 with the horizontal plane. That is, as shown in fig. 3, when the upper surface of the base 22 on which the tilt table 18 and the mounting table 24 are provided is horizontal, the angle γ of the tilt table 18 is the angle between the tilt table 18 and the base 22. As the angle γ of the inclined table 18 approaches 90 °, the space is saved, but since a large pressure is applied to the end face of the glass sheet, there is a possibility that a defect such as a crack occurs. Further, as the angle γ of the inclined table 18 approaches 0 °, the pressure applied to the glass sheet is dispersed, and defects such as edge breakage can be suppressed. In the present specification, a tray having an angle of the inclined table of 10 ° or less is referred to as a horizontally stacked tray, and a tray exceeding 10 ° is referred to as a vertically stacked tray.

The tray used may be a tray stacked horizontally or a tray stacked vertically, and in the case of a large glass plate, a large pressure is applied to the end of the glass plate due to the weight of the glass plate. Therefore, in the case of a large glass plate, it is preferable to use a tray on which the glass plates are placed in a flat stacked state. Further, the larger the glass sheet, the larger the pressure applied to the end face of the glass sheet, and therefore, the angle of the inclined table is preferably 0 ° to 5 °, more preferably 0 ° to 3 °, and still more preferably 0 ° to 1 °. However, the glass sheets may not be stored in a horizontally stacked tray when stored in a truck, a container, or the like for conveying the glass sheets. Thus, to save space, longitudinally stacked trays may also be used.

The large glass plate is, for example, a glass plate having at least one side of 2400mm or more, and a specific example thereof is a glass plate having a long side of 2400mm or more and a short side of 2000mm or more. The large glass plate is preferably a glass plate having at least one side of 2400mm or more, for example, a glass plate having a long side of 2400mm or more and a short side of 2100mm or more, and more preferably a glass plate having at least one side of 3000mm or more, for example, a glass plate having a long side of 3000mm or more and a short side of 2800mm or more. More preferably, at least one side of the glass plate is 3200mm or more, for example, 3200mm or more in the long side and 2900mm or more in the short side, and particularly preferably at least one side of the glass plate is 3300mm or more, for example, 3300mm or more in the long side and 2950mm or more in the short side.

The thickness of the glass plate is preferably 1.30mm or less. By thinning the glass plate, the weight per 1 sheet becomes light, so that the number of sheets to be mounted can be increased, and the etching time for manufacturing the liquid crystal panel can be shortened. The thickness of the glass sheet of the present invention is more preferably 0.75mm or less, still more preferably 0.65mm or less, and most preferably 0.55mm or less. The thickness may be 0.10mm or less, or 0.05mm or less. However, the thickness is preferably 0.10mm or more, more preferably 0.20mm or more, from the viewpoint of preventing deflection due to its own weight.

The glass plate is preferably used in the manufacture of displays. Since particles such as paper dust and foreign matter are present on the main surface of the glass sheet in a small amount and the surface of the glass sheet is less scratched, occurrence of defects such as disconnection can be suppressed. The display is preferably used as a substrate for a liquid crystal display or an organic EL display. Further, since the interleaving paper for glass plates of the present invention can suppress scratching of glass plates, its effect is remarkable when used for a high-definition display. Therefore, the number of pixels of the glass plate for display using the interleaving paper for glass plates of the present invention is preferably 2K (1920 × 1080) or more, more preferably 4K (3840 × 2160) or more, and still more preferably 8K (7680 × 4320) or more.

Although the glass plate interleaving paper, the glass plate laminate, and the glass plate package have been described in detail above, the present invention is not limited to the above-described examples, and various improvements and modifications can be made without departing from the scope of the present invention.

Examples

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Examples 1 to 10 are examples, and examples 11 to 13 are comparative examples. In addition, if not specifically described, the produced interleaving paper is based on JIS P8111: 1998 was measured after the conditioning treatment in the standard state. Each measurement of the interleaving paper was performed before the glass sheet laminate was used.

Smoothness was according to JIS P8119: 1998 smoothness test method (beck method) and JIS P8155: the measurement was carried out by the 2010 smoothness test method (King's type). Generally, it is known that the smoothness of the royal equation is higher than that of the beck method, but the measurement time is longer as the smoothness of the beck method is higher, and therefore, when it exceeds 100 seconds, the smoothness is obtained by the royal equation and converted into a value of the beck method. The smoothness of examples 2, 4, 6, 8, 9, 12, and 13 is obtained by obtaining the smoothness by the royal jelly formula and converting the smoothness into a value by the becker method. According to the above method, the smoothness of the interleaving paper manufactured in examples 1 to 13 was measured at substantially the center portions of the 1 st main surface and the 2 nd main surface of the interleaving paper, and the higher value was taken as the smoothness of the interleaving paper. Next, the arithmetic average height Sa and the maximum height Sz of the main surface with higher smoothness were measured using a laser microscope (VK-8500, Keyence). The arithmetic average height Sa and the maximum height Sz are measured at substantially the center of the main surface.

Sheet resistance was measured using Hiresta-UX and URS probes (MCP-HTP 14). In order to perform measurement with the probe kept upright, a load 600g in a concentric cylindrical shape was kept on the outer periphery of the probe, and the load part was kept at a sufficient distance from the sample so as not to affect the measurement. In a manner similar to the MCC-A method (measurement on the Teflon (registered trademark) surface side), 1 glass plate having a thickness of 0.5mm was laid on the non-measurement surface side of the sample as an insulator, the sample was left to stand, the probe was left to stand at the substantially central portion of the measurement surface, a voltage of 1000V was applied, and the value after 10 seconds was used as the measurement value. Note that, in this measurement, the backing paper after standing at 23 ℃ and 50% for 15 minutes was used. This is intended to simulate the condition of unwinding from the roll surface and loading in the case of actually loading the interleaving paper on the glass substrate. The measurement surface is a main surface having high smoothness out of the 1 st main surface and the 2 nd main surface of the backing paper.

Next, the compressive modulus of elasticity of the mount was measured using a constant pressure thickness tester. Then, 1600 regions were measured in 2.0mm × 1.4mm regions by using a laser microscope and a micro compression tester, and the number (number) of foreign substances having an average diameter of 10 μm to 50 μm and a particle strength C of 15(MPa) or more existing in the 1600 regions was counted and converted into particles per 1m²The number of foreign bodies present N (pieces/m)²)。

The interleaving papers for glass sheets manufactured in examples 1 to 13 were molded into a size of 500mm × 400mm, and were respectively interposed between glass sheets having a thickness of 0.5mm and a size of 470mm × 370mm to produce a glass sheet laminate in which 180 glass sheets were laminated. The protruding amount of each side of the mount was 15 mm. The glass plate was produced by the float method, the bottom surface was polished with cerium oxide, both surfaces of the polished glass plate were alkali-washed, and the glass plate was dried with clean dry air. The bottom surface refers to a main surface of a glass plate produced by the float process, which is in contact with molten tin. When glass sheets are laminated, the main surface of the backing paper having high smoothness out of the 1 st main surface and the 2 nd main surface is laminated so as to be in contact with the bottom surface of the polished glass sheet. The method of forming the glass plate used in the present invention is not limited to the float method, and may be a down-draw method, a roll-flattening method, or the like, or may be an unpolished glass plate.

Each glass plate stack was placed on a horizontally stacked tray (180 glass plates) to produce a glass plate package. The bracket is made of aluminum, and has no vibration-proof material such as rubber or spring having vibration-absorbing properties, and a mechanism for suppressing the vertical movement of the laminated body. The glass plate package thus produced was subjected to a vibration test using a vibration tester (m 120/MA1, manufactured by IMV corporation) according to JIS Z0232: the random vibration test of 2004 was vibrated in the vertical direction for 1 hour. The vibration conditions are as defined in JIS Z0232: statement of supplementary Table A.1 as defined in 2004Simulating the acceleration power spectral density condition of a general transportation environment (mainly roads) to accelerate 5.92 (m/s)²rms). The temperature in the environment is 25 +/-2 ℃ and the humidity is 50 +/-5%.

After the vibration test, the glass plate located at the upper part of the 3 rd glass plate was taken out from the lowermost part of the glass plate package, and after the glass plate was cleaned, the particle adhesion amount and the scratch on the bottom surface of the glass plate were measured by a foreign material inspection machine and evaluated.

< measurement and evaluation of particle adhesion amount and scratch on glass plate surface >

The bottom surface of the glass plate taken out from the package was passed through a washer having 2 rows of shower pipes through which pure water (ion-exchanged water) of 1MPa in pipe pressure and 20L/min in flow rate flowed and having nozzles with uniform fan-shaped discharge ports at a speed of 3m/min, and was dried by an air knife which sprays clean dry air to obtain a cleaned substrate. The cleaned substrate was measured in a Normal (1.0 μm) mode using a foreign matter inspection machine for FPD (HS-830 e, manufactured by Toray engineering Co., Ltd.) to obtain the number of particles. At least 3 sheets were measured for each test condition, and the average value was defined as the number of particles in each test condition. In the present specification, the convex attachments are particles, and the concave defects are scratches.

The adhesion of particles was measured by an FPD foreign object inspection machine before and after the production of the laminate and after vibration, and evaluated using the difference in the number of particles, and the evaluation criteria were as follows.

A: the difference of the number of the particles is less than 20000/m²。

B: the difference of the number of particles is 20000 particles/m²More than 50000 pieces/m²。

C: the difference of the number of particles was 50000 particles/m²The above.

Scratch properties of the glass plate were observed with the FPD foreign object inspection machine, and evaluated based on the following evaluation criteria.

A: the scratch existing on the bottom surface of the glass plate is less than 0.5/m²。

B: the scratch existing on the bottom surface of the glass plate is 0.5/m²Above and less than 3.0 pieces/m²。

C: the scratch existing on the bottom surface of the glass plate was 3.0 pieces/m²More than and less than 10.0 pieces/m²。

D: the scratch existing on the bottom surface of the glass plate was 10.0 pieces/m²The above.

(measurement of compressive modulus of elasticity K (MPa))

A device provided with a load mounting portion so as to be able to arbitrarily set a load in a constant-pressure thickness measuring instrument (PG-02J, manufactured by TECCLOCK Co., Ltd.) was used, and others were used without change. Note that the minimum value of the thickness reading is 1 μm. First, the sheet thickness when a load corresponding to a pressure P1(kPa) was applied to the substantially central portion of the interleaving paper with an indenter diameter of 5mm was T1(μm), and the sheet thickness when a load corresponding to a pressure P2(kPa) was applied to the substantially central portion of the interleaving paper was T2, and (strain amount) — (T1-T2)/T1 (dimensionless) was calculated. Next, the (compressive modulus of elasticity K) ═ P2-P1)/(strain amount × 10 was determined^－3) (MPa). Note that, here, P1 is 100(kPa) and P2 is 270 (kPa).

The compression elastic modulus was measured by pressing a indenter against the 1 st main surface and the 2 nd main surface of the interleaving paper, which have the greater smoothness.

(number N (pieces/m) of foreign matter having an average diameter of 10 to 50 μm and a particle strength C of 15(MPa) or more²) Measurement of (2)

The lining paper was placed on a stage of a laser microscope (VK-8500, Keyence), and the end portions were fixed with an adhesive tape so that the lining paper did not warp. 1600 regions were measured in a 2.0mm × 1.4mm region in the substantially central portion of the lining paper, and the size was calculated from the number of pixels, and particles having an average diameter of 10 μm to 50 μm were selected. The measurement may be an automatic measurement in which the next field is measured by moving 1 field at a time using the teaching function of the microscope. The pellets were set on a stage of a micro compression tester (MCT-510, manufactured by Shimadzu corporation). Note that the minute compression testThe machine used a tester having a diamond plane indenter with a diameter of 50 μm, a test force resolution of 5 μ N, and a displacement resolution of 0.01 μm. The outer shape of the particles was confirmed by a microscope attached to a measuring tester, and the long diameter and the short diameter were measured to calculate the average diameter by addition and averaging. The particles were subjected to a test force at a set reaching test force of 20mN and a load speed of 0.44mN/sec, and a point at which the average diameter after compression was 10% smaller than the average diameter before compression was set as a 10% compression point. Using the test force at this time, the formula Cx ═ 2.48 × (test force at 10% compression point)/(average particle diameter), which is known as a general calculation formula of particle fracture strength, was used²Cx was calculated, and the calculated Cx was used as the particle strength C. Then, the number N (number/m) of foreign matters was calculated by counting particles having a particle strength C of 15(MPa) or more²)。

Note that, in general, a test force of more than 15(MPa) was applied, and a point of particle destruction (a point where the test force was substantially constant and only the amount of displacement was largely changed due to particle destruction) was set as a point of destruction, and Cs × (2.48 × (test force at the point of destruction)/(average particle diameter) was calculated using the test force at this time²The calculated Cs is often used as the particle intensity C.

However, in the case of particles having Cx calculated using the test force at the 10% compression point of 15(MPa) or so, since the breakage point of the particles is not detected, in the present specification, Cx is calculated using the test force at the 10% compression point and the value thereof is defined as the particle strength C. In addition, when the breaking point of the particles is observed before the 10% compression point is reached, the particle shape significantly changes at that time, and therefore the value of Cs is used as the particle strength in this case.

(example 1)

After pulping the pulp slurry of NBKP 100% using a double disc refiner, the stock slurry was sprayed at a stock concentration of 1% onto a fourdrinier forming machine so as to obtain a basis weight shown in table 1, to form a paper layer, and then the paper layer was dried by passing the paper layer through a multi-drum dryer. As the water used as the raw material, pure water treated with a 40 μm filter was used. Then, the sheet was treated by hot soft rolling at a temperature of 100 ℃ and a nip pressure of 10 (kN/m). ObtainedThe weight per unit area of the lining paper was 45.1g/m²A thickness of 80 μm and a density of 0.53 (g/cm)³) The smoothness of the 1 st main surface was 25 seconds, and the smoothness of the 2 nd main surface was 23 seconds.

(example 2)

Interleaving paper was obtained in the same manner as in example 1, except that the thermal soft rolling treatment was performed at a temperature of 150 ℃ with a temperature gradient and a nip pressure of 120(kN/m) with a thermal gradient.

(example 3)

Interleaving paper was obtained in the same manner as in example 1, except that the raw material composition was changed to NBKP 50%, lbkp (a) 50%, the filter for water used was a filter with an open diameter of 20 μm, and the paper was subjected to a rolling process using hard rolling at a nip pressure of 30 (kN/m).

(example 4)

Interleaving paper was obtained in the same manner as in example 1, except that the raw material system composed of pulp and water shown in example 3 was used, and the processing was performed at a temperature of 150 ℃ and a nip pressure of 150(kN/m) as the rolling processing.

(example 5)

Interleaving paper was obtained in the same manner as in example 3, except that a filter having an open diameter of 5 μm was used as the water filter and the filter was treated at a nip pressure of 50 (kN/m).

(example 6)

Interleaving paper was obtained in the same manner as in example 1, except that the raw material system composed of pulp and water shown in example 5 was used, and after cooling treatment was performed using water and low-temperature air blow before rolling treatment, the resulting material was subjected to rolling treatment at a temperature of 200 ℃ and a nip pressure of 170 (kN/m).

(example 7)

A liner paper was obtained in the same manner as in example 1, except that the raw material slurry was dried by a yankee dryer without being subjected to the calendering.

(example 8)

Interleaving paper was obtained in the same manner as in example 4, except that the raw material composition was changed to NBKP 50%, LBKP (B) 50% and the filter having an opening diameter of 40 μm was used as the water filter shown in example 1. Lbkp (a) and lbkp (b) are hardwood bleached kraft pulps derived from wood from different origins, respectively.

(example 9)

A liner paper was obtained in the same manner as in example 6, except that the paper forming speed was reduced by 20%, and a drying roll at 150 ℃ was provided before winding the liner paper, and drying treatment was performed to reduce the amount of moisture.

(example 10)

A backing paper was obtained in the same manner as in example 1 except that humidification treatment was performed before the backing paper was taken up to increase the moisture content.

(example 11)

A liner paper was obtained in the same manner as in example 1, except that the raw material slurry was not subjected to a calendering process after being made into a sheet.

(example 12)

Paper was made from a raw material slurry beaten so as to have a freeness of 200mL CSF using a raw material system comprising the pulp shown in example 8 and water, wet paper was prepared using a water-imparting device, and then 10-stage super-calendering was carried out at a temperature of 150 ℃ and a nip pressure of 200kN/m to obtain a liner paper as a glass paper.

(example 13)

A liner paper was obtained in the same manner as in example 1 except that the stock system comprising the pulp and water shown in example 3 was used, the paper making rate was decreased by 20%, and the paper was subjected to a calendering treatment at a temperature of 100 ℃ and a nip pressure of 350 kN/m.

[ Table 1]

< results >

Table 1 shows the measurement results and the evaluation results. According to table 1, when the smoothness is 20 seconds or more, the adhesion of the particles is all a or B. On the other hand, when the smoothness is less than 20 seconds, the adhered amount of the particles is all C. In addition, when the compressive modulus of elasticity K is 8.5MPa or less, all of the scratch properties are a or B. On the other hand, when the compressive modulus of elasticity K exceeds 8.5MPa, the scratch resistance is C or D.

The present application is based on Japanese patent application No. 2020-195392, filed on 25/11/2020, and Japanese patent application No. 2021-187432, filed on 17/11/2021, the contents of which are incorporated by reference in the present specification.

Claims

1. A sheet of interleaving paper for glass plates, having a thickness of 30 to 150 μm,

the smoothness of at least one main surface of the slip sheet for glass sheets is 20 seconds or more,

the modulus of elasticity K in compression measured on the main surface is 1.0MPa to 8.5 MPa.

2. The interleaving paper for glass sheets as claimed in claim 1, wherein the arithmetic average height Sa of the main surface is 2.5 μm or more.

3. The interleaving paper for glass plates according to claim 1 or 2, wherein the maximum height Sz of the main surface is 45 μm or more.

4. The interleaving paper for glass sheets as claimed in any one of claims 1 to 3, wherein the density of the interleaving paper for glass sheets is 0.4g/cm³～1.6g/cm³，

The smoothness of the main surface is 20 seconds to 400 seconds.

5. The interleaving paper for glass sheets as claimed in any one of claims 1 to 4, wherein the sheet resistance of the interleaving paper for glass sheets is 5.0 x 10¹⁰Ω/□～5.0×10¹³Ω/□。

6. The interleaving paper for glass sheets as claimed in any one of claims 1 to 5, wherein a hard foreign matter resistance value KN, which is a product of the compressive elastic modulus K and the number N of foreign matters contained in the interleaving paper for glass sheets and having an average diameter of 10 to 50 μm and a particle strength C of 15MPa or more, is 35.0 or less, the unit of the compressive elastic modulus K is MPa, and the unit of the number N of foreign matters is pieces/m²。

7. According to claim 1 to 6The interleaving paper for glass sheets, wherein the hard foreign matter resistance value KN, which is the product of the compression elastic modulus K and the number N of foreign matters with the average diameter of 10 to 50 [ mu ] m and the particle strength C of 15MPa or more contained in the interleaving paper for glass sheets, is 15.0 or less, the unit of the compression elastic modulus K is MPa, and the unit of the number N of the foreign matters is one/m²。

8. The interleaving paper for glass plates as claimed in any one of claims 1 to 7, wherein the main surface is a surface in contact with an electronic circuit forming surface of a glass plate.

9. A glass sheet laminate comprising at least 2 glass sheets stacked, the glass sheet laminate having the interleaving paper for glass sheets according to any one of claims 1 to 8 between the glass sheets.

10. A glass plate package comprising the glass plate laminate according to claim 9 and a carrier on which the glass plate laminate is placed.