TW202220909A - Paper spacer for glass plate, glass plate laminate body and glass plate bale body wherein the thickness of the paper spacer for the glass plate is 30 [mu]m or more and 150 [mu]m or less - Google Patents

Abstract

The present invention relates to a paper spacer for a glass plate, a glass plate laminate body, and a glass plate bale body, wherein the paper spacer for the glass plate is characterized in that the thickness of the paper spacer for the glass plate is 30 [mu]m or more and 150 [mu]m or less, and the smoothness of at least one main surface of the paper spacer for the glass plate is 20 seconds or more, and the compressive elastic modulus K is 1.0 MPa or more and 8.5 MPa or less, the arithmetic average height Sa of the main surface is 2.5 [mu]m, and the maximum height is 45 [mu]m.

Description

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

The present invention relates to a spacer paper for glass plates, a glass plate laminate, and a glass plate package.

For example, the glass plate used for LCD (Liquid Crystal Display, liquid crystal display) or OLED (Organic Light-Emitting Diode, organic light-emitting diode) and other flat panel displays will form fine electronic components on the surface of the glass plate, so the surface is very small. Damage or dirt can cause problems such as disconnection. Therefore, the surface of the glass plate requires high cleanliness.

In order to improve the transportation efficiency, the glass plates are transported in the state of overlapping a plurality of glass plates. In this case, a spacer paper for a glass plate (hereinafter also referred to as "spacer paper") is interposed between the glass plate and the glass plate to prevent damage or the like on the surface of the glass plate during transportation.

However, since the glass plate is laminated in the state that its surface is pressed against the spacer paper, particles such as paper powder or foreign matter generated by the spacer paper adhere to the surface of the glass plate, mainly due to the inorganic foreign matter in the spacer paper to the glass plate. Risk of damage to the surface. Therefore, there is a need for a spacer paper for a glass plate, which is less likely to adhere fine particles to the surface of the glass plate, and which can suppress damage to the glass plate.

Patent Document 1 discloses a spacer paper for a glass plate having a hardened portion and a non-hardened portion, and is intended to suppress the generation of particles by setting the smoothness of the hardened portion to 20 seconds or more. Moreover, in patent document 2, it is intended to reduce the damage to a glass plate by making smoothness 70 second or more. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2016-34843 [Patent Document 2] Japanese Patent Laid-Open No. 2016-35125

[Problems to be Solved by Invention]

However, with the recent development of high-definition displays, the width or pitch of wirings formed on the surface of the glass plate has become finer than before, and the quality required for the surface of the glass plate has become higher. Therefore, for example, even if the spacer paper for a glass plate of Patent Document 1 or 2 is used, there are problems such as disconnection of wiring on the glass plate due to adhesion of particles on the glass plate or damage to the surface of the glass plate. The quality of spacer paper for boards. Therefore, in addition to the said prior art, the spacer paper for glass plates which suppresses the damage which generate|occur|produced on the surface of a glass plate has been proposed. As an example, the spacer paper for glass plates which is disclosed in Unexamined-Japanese-Patent No. 2016-006240 which regulates the content of the mineral of a specific Mohs hardness or more can be mentioned. However, the glass plate used in the high-definition display may cause problems even if the spacer paper containing only foreign matter below a specific Mohs hardness is used. As a result of intensive research, the inventors found that even in the case where there are only foreign objects with a specific Mohs hardness or less, because the particle strength of these foreign objects is relatively large, there may be cases in which damage to the glass plate may occur.

An object of the present invention is to provide a spacer paper for a glass plate, which can cope with high-definition displays, reduce particles from adhering to a glass plate, and suppress damage to the surface of the glass plate. [Technical means to solve problems]

(1) The spacer paper for glass plates of the present invention is characterized in that the thickness is not less than 30 μm and not more than 150 μm, the smoothness of at least one main surface of the spacer paper for glass plates is not less than 20 seconds, and the compression measured on the main surface is characterized by: The elastic modulus K is 1.0 MPa or more and 8.5 MPa or less. (2) The spacer paper for glass plates according to (1), wherein the arithmetic mean height Sa of the main surface is 2.5 μm or more. (3) The spacer 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 spacer paper for a glass plate according to any one of (1) to (3), wherein the density of the spacer paper for a glass plate is 0.4 (g/cm ³ ) or more and 1.6 (g/cm ³ ) or less, and the above The smoothness of the main surface is 20 seconds or more and 400 seconds or less. (5) The spacer paper for glass plates according to any one of (1) to (4), wherein the sheet resistance of the spacer paper for glass plates is 5.0×10 ¹⁰ (Ω/□) or more and 5.0×10 ¹³ (Ω/□) □) or below. (6) The spacer paper for glass plates according to any one of (1) to (5), wherein the compressive elastic modulus K (MPa) and the average diameter contained in the spacer paper for glass plates are 10 μm or more and 50 μm The product of the number N (pieces/m ² ) of foreign matter having a particle strength C of 15 (MPa) or less, ie, a hard foreign matter resistance value KN, is 35.0 or less. (7) The spacer paper for glass plates according to any one of (1) to (6), wherein the compressive elastic modulus K (MPa) and the average diameter contained in the spacer paper for glass plates are 10 μm or more and 50 μm The product of the number N (pieces/m ² ) of foreign matter having a particle strength C of 15 (MPa) or less, that is, a hard foreign matter resistance value KN is 15.0 or less. (8) The spacer paper for a glass plate according to any one of (1) to (7), wherein the main surface is a surface in contact with the electronic circuit forming surface of the glass plate. (9) A glass plate laminate comprising at least two or more glass plates laminated, wherein the glass plate laminate has any one of (1) to (8) between the glass plate and the glass plate. Spacer paper for glass plates. (10) A glass plate package comprising the glass plate laminate according to (9), and a pallet on which the glass plate laminate is placed. [Effect of invention]

ADVANTAGE OF THE INVENTION According to this invention, the spacer paper for glass plates can be provided which can cope with the high definition of a display, and can suppress that a fine particle adheres to a glass plate or a glass plate surface produces damage.

Hereinafter, preferred embodiments of the spacer paper for a glass plate of the present invention will be described. The embodiments shown below are examples, and the present invention is not limited to these embodiments. In addition, the glass plate is also expressed as a glass substrate.

From the viewpoint of transportation efficiency, a glass plate is transported in a state where at least two or more glass plates are stacked and placed on a pallet. The thing which laminated|stacked the glass plate of at least 2 or more sheets is called a glass plate laminated body, and the thing which mounted the glass plate laminated body on a pallet is called a glass plate package.

In the glass plate laminate, when the glass plates come into contact with each other, there is a possibility that the surface of the glass plate is damaged. It is known that when such damage occurs on the electronic circuit forming surface of the glass plate, problems such as disconnection occur. Therefore, by interposing the spacer paper for a glass plate between the glass plates, the electronic circuit formation surface of the glass plate is prevented from being damaged.

However, during storage or transportation of the glass plate, particles generated from the spacer paper may adhere, and the surface of the glass plate may be damaged mainly by the inorganic foreign matter in the spacer paper. With the recent development of high-definition displays, the width or pitch of wirings formed on the surface of the glass plate has become finer than before, and the quality required for the surface of the glass plate has become higher. Therefore, even if the spacer paper for a glass plate, which has not been a problem in the past, is used, problems such as disconnection of the wiring on the glass plate occur.

The inventors of the present invention have found that, by making the smoothness of the spacer paper more than a certain level, even if it is a high-definition display, it is possible to suppress the inconvenience caused by the adhesion of particles. However, even in the case of increasing the smoothness of the spacer paper and reducing the adhesion amount of particles, there are cases in which the damage to the surface of the glass plate causes a problem. Therefore, it is necessary to suppress the adhesion of fine particles and to suppress the occurrence of damage on the surface of the glass plate.

Therefore, the inventors of the present invention have investigated damages that cause problems such as disconnection. As a result, it was found that the cause was foreign matter having an average diameter of 10 μm or more and a particle strength C of 15 (MPa) or more. Among them, damage caused by foreign matter having an average diameter of 10 μm or more and 50 μm or less and a particle strength C of 15 (MPa) or more is not a problem in the past. However, it is thought that the quality required for the surface of a glass substrate becomes high with the high definition of a display, and as a result, the damage by these foreign substances becomes a problem.

In addition, it is considered that the foreign matter having an average diameter of less than 10 μm is likely to be buried in the spacer paper for a glass plate, and thus is unlikely to cause damage to the glass plate. Moreover, if it is a foreign material whose particle strength C is less than 15 (MPa), even if the said foreign material is pressed into a glass plate, it is thought that it is hard to generate|occur|produce damage. In addition, even when damage occurs, it is considered that it is difficult to cause a disconnection defect or the like because of its small size. Therefore, it is important to use a spacer paper controlled so as to reduce the foreign matter contained in the spacer paper with an average diameter of 10 μm or more and 50 μm or less and a particle strength C of 15 (MPa) or more.

The foreign matter in the spacer paper is contained as impurities in the pulp that becomes the raw material of the spacer paper, or dust generated by the production equipment of the spacer paper, or in the water used in the production process of the spacer paper, and cannot be removed by a filter or the like. mixed into the spacer paper. In addition, in the process of producing the spacer paper for glass plates other than the spacer paper for glass plates, those added as additives remain in the piping or on the surface of the rollers that come into contact with the paper when passing through the paper, etc., and adhere to the surface of the spacer paper when producing the spacer paper for glass plates, etc. The reason is that foreign matter may also be mixed in, and there may also be foreign matter with particle strength C of 15 (MPa) or more in the mixed foreign matter. Therefore, it is difficult to completely remove foreign matter having an average diameter of 10 μm or more and 50 μm or less and a particle strength C of 15 (MPa) or more.

Therefore, the inventors focused on the cushioning properties of the spacer paper. The cushioning property of the spacer paper is defined by the compressive elastic modulus K (MPa) in the thickness direction of the spacer paper. A smaller value of the compressive elastic modulus K (MPa) means higher cushioning properties, and a larger value means lower cushioning properties. As a result of intensive research, the inventors found that a spacer paper with a higher cushioning property can suppress the mixing of foreign matter with an average diameter of 10 μm or more and 50 μm or less and a particle strength C of 15 (MPa) or more into the spacer paper. damage.

The reason for this is considered to be that, when the glass plate is laminated, the higher the cushioning property of the spacer paper, the easier it is for foreign matter to be buried in the spacer paper, so the reduction is reduced from an average diameter of 10 μm to 50 μm and a particle strength C of 15 (MPa) Damage caused by the above foreign objects.

(Raw material pulp) The kind of the raw material pulp is not particularly limited, and one having properties required as spacer paper can be favorably used. For example, chemical pulps such as kraft pulp (KP), sulfite pulp (SP), and soda pulp (AP); mechanical pulps such as ground wood pulp (GP), thermomechanical pulp (TMP), and chemithermomechanical pulp (CTMP) may be mentioned. ; Semi-chemical pulps such as chemical finely ground pulp (CGP) and semi-chemical pulp (SCP) as the mechanical-chemical pulp in between; non-wood fiber pulps with kenaf, incense, mulberry, goose bark, hemp, etc. as raw materials; Synthetic pulp, synthetic fibers, recycled pulp (DIP), etc. Pulp can be bleached or unbleached, for example, bleached hardwood kraft pulp (LBKP), bleached softwood kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), and softwood unbleached kraft pulp (NUKP) are available. Moreover, carbon nanofiber (CNF) may be contained. The raw pulp can be recycled pulp, virgin pulp, a mixture of recycled pulp and virgin pulp. In particular, in order to suppress contamination or damage to the glass plate by particles or foreign matter, bleached LBKP or NBKP is particularly preferred, and furthermore, pulp from which foreign matter has been removed by a cyclone, a flotation machine, or the like is preferred. The foreign matter in the pulp refers to the part other than the fiber component contained in the pulp. Compounds such as SiC, ZrO ₂ , Al ₂ O ₃ , TiO ₂ , SiO ₂ , Fe, Fe ₂ O ₃ , Cr, Ni, CaF ₂ , MgO, CaCO ₃ , Al, Cu and the like are mixed into the pulp. In the case of foreign substances such as alloys, aromatic polyetherketone (PEEK), polyphenylene sulfide (PPS), ultra-high molecular weight polyethylene (UPE), and epoxy resins. These are believed to be incorporated from minerals or equipment during the steps from the harvesting of the trees to the pulping of pulp chips.

(Manufacturing method of spacer paper for glass plate) The manufacturing method of the spacer paper for glass plates is demonstrated using the conceptual diagram which shows one Embodiment of the manufacturing method of the spacer paper for glass plates shown in FIG.

In the manufacturing apparatus 100 of the spacer paper for glass plates, the raw material slurry of the spacer paper for glass plates (a slurry-like liquid dissociated by diluting the pulp with water) is beaten, and then flows from the headbox 112 to the lower part of the line part 114. 116 and above are supplied in sheets. The raw material slurry supplied to the lower wire 116 is then sandwiched by the lower wire 116 and the upper wire 118, spread to a uniform thickness, and dehydrated to form wet paper (paper).

The lower wire 116 and the upper wire 118 of the wire portion 114 are formed into an endless belt-shaped permeable membrane. Specifically, it is a net made of plastic or metal material, or an endless belt made of felt containing natural or synthetic fibers. The lower wire 116 and the upper wire 118 are mounted on a plurality of rollers, so that the driving force of the motor (not shown) is transmitted to the driving rollers among the plurality of rollers, thereby moving around at a specific speed.

The wet paper formed in the wire portion 114 is transported to a pressing portion 120 having a pressing roller, an endless belt-shaped felt, and a pressing roller equivalent, where it is further dehydrated and pressed.

The wet paper passing through the pressing part 120 is transported to the drying part 124 composed of a plurality of rollers, and when passing through the drying part 124, it is dried, for example, in an environment of about 120°C.

When passing through the drying section 124, if the wet paper is directly transported at a high speed, the paper may be interrupted, so it is transported in a state where an auxiliary member called a canvas is in contact with the wet paper.

The paper dried in the drying section 124 is conveyed to the calendering section 126, and the front and back surfaces are smoothed by applying a specific linear pressure to the paper by nip conveying with a calender roll or the like. In the calendering process, various calenders such as soft calendering, hard calendering, super calendering, and hot calendering can be used, which are not limited to online but also offline. In addition, multi-stage rolling may also be employed. Furthermore, if necessary, a coater unit may be provided between the drying unit 124 and the calendering unit 126 to coat the surface of the smoothed paper with paint or the like.

The paper calendered in the calender part 126 is wound up on the reel 128 as a spacer paper for a glass plate, and is made into a roll shape (hereinafter referred to as a large roll 130).

The spacer paper for glass plates made into the large roll 130 is usually cut to a width corresponding to the product, for example, and rolled up, and then a long glass plate with a specific length of about 8,000 m to 10,000 m is wound with spacer paper to make spacer paper rolls Cartridge 42 .

The spacer paper for a glass plate is fed out from the large roll 130 , is cut in a predetermined width by the cutter 134 (cut in the longitudinal direction), and is wound up by the winder 136 . When the spacer paper for glass sheets sent out from the large roll 130 reaches a specific length, it is cut by the cutter 134 to a specific length (cutting in the width direction) to make a long glass sheet wound with a specific width. The spacer paper roll 42 is made of spacer paper.

The long glass plate wound into the spacer paper roll 42 is cut with spacer paper into slices (rectangular shape) of the size corresponding to the glass plate for lamination, and is interposed between the glass plates for lamination.

(thickness of spacer paper) The thickness of the spacer paper can be measured according to the paper thickness measurement specified in JIS P8118:2014. For the measurement, for example, an automatic lift-type paper thickness gauge (manufactured by Kumagai Riki Kogyo Co., Ltd., TM-600) can be used.

Here, if the spacer paper is too thin, even when the cushioning properties of the spacer paper are high, damage is likely to occur because foreign matter is not buried in the spacer paper. In addition, since the strength of the spacer paper is weakened, inconveniences such as paper breakage are likely to occur during the production of the spacer paper, and the production efficiency is lowered. Therefore, the thickness of the spacer paper for a glass plate 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. In addition, when the spacer paper is too thick, the volume and weight of the spacer paper increase, so that the number of glass plates that can be laminated on the pallet decreases. Therefore, the thickness of the spacer paper for glass plates 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.

(compression elastic modulus) The compressive elastic modulus K (MPa) of the spacer paper for a glass plate of the present invention is 1.0 MPa or more and 8.5 MPa or less. The smaller the compressive elastic modulus K, the higher the cushioning properties of the spacer paper, so that damage caused by foreign matter having an average diameter of 10 μm or more and 50 μm or less and a particle strength C of 15 (MPa) or more can be suppressed. Here, among glass plates, it is the electronic circuit formation surface that is particularly required to suppress adhesion and damage of fine particles. Therefore, the effect of the present invention can be exhibited when the compressive elastic modulus K (MPa) of the portion in contact with the glass plate in the main surface of the spacer paper on the side in contact with the electronic circuit forming surface is within the above range. The compressive elastic modulus K (MPa) is more preferably 8.0 MPa or less, still more preferably 5.0 MPa or less, still more preferably 3.0 MPa or less, and most preferably 2.0 MPa or less. The lower limit of the compressive elastic modulus of the spacer paper is 1.0 MPa or more. When the compressive elastic modulus of the spacer paper is equal to or more than the above lower limit, improvement in durability can be expected. In addition, in this specification, the compression elastic modulus K (MPa) of the spacer paper for glass plates is measured by the following method.

(Measuring method of compressive elastic modulus) The compressive elastic modulus of the spacer paper can be measured using, for example, a constant pressure thickness measuring device (manufactured by TECLOCK, PG-02J). The paper thickness when a load corresponding to the pressure P1 (kPa) is applied to the approximate center of the spacer paper is T1 (μm), and the paper thickness when a load corresponding to the pressure P2 (kPa) is applied to the approximate center of the spacer paper The thickness is set to T2, and (strain amount)=(T1-T2)/T1 (dimensionless) is calculated. Next, (compressive elastic modulus)=(P2−P1)/(strain amount×10 ⁻³ )(MPa) was obtained. In addition, in this specification, P1=100 (kPa), P2=270 (kPa).

The compressive elastic modulus K of the spacer paper can be mainly controlled by the apparent density of the spacer paper and the density of the outermost layer. Apparent density is the density of the paper as a whole. Generally, as the basis weight increases, the thickness of the paper increases, but as the basis weight of the spacer paper decreases, the thickness of the spacer paper increases and the density becomes low, and the compressive elastic modulus K decreases, that is, the cushioning property tends to increase. As a method of thickening the spacer paper under the same basis weight, methods such as increasing the content of conifer pulp with a high proportion of long fibers in the raw material, adjusting the beating amount to increase the freeness of the raw pulp, and adding a bulking agent can be used. In addition, in order to prevent the chemical|medical agent, such as a bulking agent, from contaminating the glass plate, it is desirable to add a small amount.

The density of the outermost layer can be controlled by the pressure applied to the paper by the calender roll (hereinafter referred to as "calendering pressure") in the calendering section. That is, when the calendering section 126 is sandwiched and conveyed, the smaller the nip pressure is, the smaller the compressive elastic modulus becomes, and the spacer paper with higher cushioning properties can be obtained. However, this operation tends to reduce the close contact between fibers, which may lead to the increase of particles generated from the spacer paper. Therefore, it is preferable to reduce the apparent density of the spacer paper, and on the other hand, to harden the surface to obtain a spacer paper with cushioning properties as a whole. The compressive elastic modulus K may not always be consistent with the apparent density, and it is also affected by the density of the outermost layer. Therefore, it can be speculated that the greater the density difference in the direction of the paper layers of the spacer paper, the more the compressive elastic modulus K and the apparent density will deviate. .

High-smooth paper can be obtained by increasing the temperature of the hot roll surface or rolling, increasing the contact time, and increasing the number of rollings during the hot calendering process. On the other hand, the increase in rolling pressure or contact time and number of times will reduce the bulkiness. Here, by applying a temperature higher than the temperature of the paper to the heat roller, the temperature gradient in the thickness direction of the paper becomes larger, and the plastic deformation of the surface of the paper layer is promoted. Since the inside of the paper layer is difficult to plastically deform, the heat roller is set as High temperature is easy to produce fluffy spacer paper with cushioning properties, which is suitable for the present invention. For the same reason, by lowering the temperature of the paper before calendering, the temperature gradient can be further increased, which is more suitable. As a cooling method, the method of using air, water, and a cooling roll can be mentioned. Furthermore, when a small amount of water is applied to the paper, it is immediately dried by a low-temperature dry blast, and the paper is cooled by capturing the heat of evaporation and then calendered. The calendering treatment with a large temperature gradient is carried out before the capillary infiltration, so it can inhibit the plastic deformation inside the paper layer and become fluffy, which is particularly suitable. By making the time of using water extremely short, processing can be performed without occurrence of coarsening due to the destruction of the bond between fibers or the deformation of the fibers.

In addition, in hot soft calendering, it is known that there is a difference in the degree of increase in smoothness between the paper on the side of the heat roll made of metal and the paper on the side of the elastic roll made of resin. Since this kind of treatment can especially improve the smoothness of one surface, it is suitable for obtaining a spacer paper with a high smoothness of the surface of the spacer paper and a low density of the spacer paper as a whole. In one aspect of the present invention, the temperature suitable for obtaining high-smooth paper is 25°C to 250°C. The higher the temperature, the higher the smoothing effect can be obtained. However, if the temperature exceeds 250°C, problems such as paper burn and uneven smoothing in the width direction are likely to occur, and the deterioration of the elastic roller is accelerated. Although smoothing is possible even if it is less than 100°C, since the smoothing by the above-mentioned temperature gradient is not sufficient, it is desirable to be 100°C or more especially when obtaining a spacer paper with a smoothness exceeding 100 seconds.

In addition, in one aspect of the present invention, the rolling pressure suitable for obtaining highly smooth paper is, for example, 5 kN/m to 350 kN/m. If the rolling pressure is less than 5 kN/m, the smoothing will be insufficient, and if it exceeds 350 kN/m, the elastic roll will be easily deteriorated. In addition, as a method of exhibiting the same effect, it may be constituted by laminating paper having a plurality of densities. In this way, the type of calendering treatment, the temperature in the calendering treatment, and the calendering pressure, etc., can be used to obtain a spacer paper with a high surface smoothness and a small compressive elastic modulus.

(smoothness) The smoothness of at least one main surface of the spacer paper for a glass plate of the present invention is 20 seconds or more. The smoothness of the spacer paper means the unevenness of the surface of the spacer paper or the unevenness of the fibers below the height of several μm to several mm, and high smoothness is achieved by making the fibers close to each other.

That is, it can be achieved by the following methods: using pulp with short fiber length to eliminate the voids between fibers, or strengthening the beating to strengthen the cross-linking of fibers, reducing the surface roughness of the drying drum or improving the cleanliness in the drying step, Control the papermaking speed and humidification and dehumidification environment while controlling the humidity while making paper, and improve the calendering pressure, etc. Since the higher smoothness means that the fibers or the fibers and the foreign matter are in close contact with each other, the generation of fine particles such as paper dust and foreign matter from the paper surface can be suppressed. When the smoothness is increased by calendering the spacer paper by high-pressure calendering, the spacer paper is flattened, so that the compressive elastic modulus K tends to increase. However, when the smoothness of the spacer paper is less than 20 seconds, particles are easily generated. Therefore, the smoothness can be 20 seconds or more and the compressive elastic modulus K can be 1.0 MPa or more by making efforts not only in the rolling pressure, but also in the type of calendering treatment and the temperature during calendering treatment as described above. Below 8.5 MPa, both particle suppression and damage suppression can be achieved.

Here, among the glass plates, it is the electronic circuit formation surface that is particularly required to suppress contamination, that is, to suppress adhesion of fine particles. Therefore, the effect of this invention can be exhibited when the smoothness of the part which contacts the glass plate among the main surfaces of the spacer paper on the side in contact with the electronic circuit formation surface is 20 seconds or more.

However, when the smoothness is too high, the adhesiveness of the spacer paper becomes high, and the adhesion to the glass plate or the conveying roller is caused by static electricity. Therefore, for example, when the glass plate or the spacer paper is removed from the glass plate laminate (hereinafter, also referred to as "separation"), problems such as the spacer paper sticking to the glass plate are likely to occur. Therefore, the smoothness of the spacer paper surface is preferably 400 seconds or less, more preferably 100 seconds or less, still more preferably 70 seconds or less, and particularly preferably 50 seconds or less. If the smoothness of the surface of the spacer paper is below the above upper limit, the occurrence of defects such as the spacer paper sticking to the glass plate during disassembly can be reduced.

In this specification, smoothness can be measured by the measurement method described in the Example mentioned later. In addition, about the measurement site|part of smoothness, what is necessary is just to measure at the site|part which can contact the glass plate of the spacer paper, and it does not specifically limit, For example, it can measure at the approximate center part of the spacer paper.

(Sheet resistance (Ω/□)) The inventors of the present invention conducted intensive research, and as a result, found that there is a relationship between the adhesion of the spacer paper and the substrate and the chargeability of the spacer paper. The chargeability of the spacer paper can be represented by the sheet resistance (surface resistivity) of the spacer paper. Sheet resistance represents the resistance value per unit area (1 cm ² ) of thin films such as paper or film. The higher the sheet resistance, the lower the conductivity and the easier it is to be charged. The sheet resistance is mainly affected by the moisture content of the spacer paper. Even if the moisture content is the same, the electrical conductivity is also different depending on the density or entanglement of the fibers, the state of the fibers such as orientation, or the components contained, and the thickness of the spacer paper. The combination of these can control the value of sheet resistance. The higher the water content and the denser the fibers, the lower the sheet resistance. In addition, in order to reduce sheet resistance, antistatic agents can be added within the range that does not reduce the quality of the spacer paper. Sheet resistance can be measured using, for example, Hiresta-UX MCP-HT800 (manufactured by Mitsubishi Chemical Analytech).

In the spacer paper for a glass plate of the present invention, by setting the sheet resistance to be 5.0×10 ¹³ Ω/□ or less, the occurrence of defects such as the above-mentioned spacer paper sticking to the glass plate can be reduced. Therefore, the sheet resistance of the spacer paper is preferably 5.0×10 ¹³ Ω/□ or less, more preferably 2.5×10 ¹³ Ω/□ or less, and still more preferably 1.0×10 ¹³ Ω/□ or less. If the sheet resistance of the spacer paper is below the above upper limit, the occurrence of defects such as the spacer paper sticking to the glass plate during disassembly can be reduced.

When the sheet resistance of the spacer paper is too low, when the spacer paper is loaded on the vertical pallet, the spacer paper and the glass plate may not be sufficiently adhered, and the spacer paper may peel off. In addition, if the sheet resistance of the spacer paper is reduced and the water retention capacity of the spacer paper is increased, there may be problems such as extreme adhesion of the spacer paper to the glass medium. Therefore, the sheet resistance of the spacer paper for a glass plate of the present invention is preferably 5.0×10 ¹⁰ Ω/□ or more, more preferably 7.5×10 ¹⁰ Ω/□ or more, and still more preferably 1.0×10 ¹¹ Ω/□ or more. If the sheet resistance of the spacer paper is more than the above lower limit, the problem of peeling of the spacer paper and the occurrence of defects such as extreme sticking can be reduced.

(Hard foreign matter resistance value) The hard foreign matter resistance value is determined by the compressive elastic modulus K (MPa) and the number of foreign matter contained in the spacer paper with an average diameter of 10 μm or more and 50 μm or less and particle strength C of 15 (MPa) or more. The product definition of N(pieces/m ² ).

The smaller the hard foreign matter resistance value KN of the spacer paper, means that the average diameter that causes damage is 10 μm or more and 50 μm or less and the particle strength C is 15 (MPa) or more. The smaller the foreign matter or the smaller the compression modulus K, The damage to the glass plate can be further reduced. The above-mentioned hard foreign matter resistance value is preferably 35.0 or less, more preferably 30.0 or less, still more preferably 15.0 or less, particularly preferably 10.0 or less, and most preferably 5.0 or less. In order to reduce the hard foreign matter resistance value KN, 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, more preferably 0.5 or more.

(Foreign matter with an average diameter of 10 μm or more and 50 μm or less and a particle strength C of 15 (MPa) or more) In this specification, particle strength is used as the evaluation of foreign matter. As the evaluation of foreign matter in spacer paper other than particle strength, there is a method of evaluating using Mohs hardness, such as Japanese Patent Laid-Open No. 2016-006240, for example. Mohs hardness is defined as "Which side is damaged when an object is scratched with other objects", and it is usually a standard for comparing the hardness of lump minerals with each other. In addition, since the Mohs hardness is a relative value, even if the same Mohs hardness value is not necessarily the same hardness (particle strength), it is impossible to quantitatively express which side is more susceptible to damage. Wipe is impossible to know.

Here, the results of investigation by the present inventors regarding the relationship between particle strength and Mohs hardness are shown in FIG. 1 . FIG. 1 is a graph showing the results of measuring the particle strength of a plurality of particles with respect to various components of minerals whose Mohs hardness is generally known or considered to be minute foreign substances in spacer paper. Figure 1 is a boxplot showing the first quartile, second quartile, third quartile, maximum, minimum, arithmetic mean, and outliers. Outliers are numbers greater than the third quartile plus 1.5 times the interquartile range (difference between the third quartile and the first quartile), or less than the first quartile minus Data on numbers obtained by removing 1.5 times the interquartile range of values. The maximum value is the largest of the data excluding outliers. The minimum value is the smallest among the data excluding outliers. In the boxplot of Figure 1, outliers are represented by white circles, and the arithmetic mean is represented by black circles. The inventors found that, as shown in Fig. 1, the particle strength of tiny foreign objects is roughly close to the sequence of Mohs hardness, but they are not necessarily consistent. There is an inversion between the value of Mohs hardness and the value of particle strength, or even the same. Particles of the same type have large differences in particle strength.

These are generated in different ways depending on the respective particles, and it is presumed to be caused by differences in density, crystallite orientation state, or the existence of voids. Therefore, even in the case where there are only foreign objects with a specific Mohs hardness or less, since the particle strength of these foreign objects is relatively large, there may be cases in which damage to the glass plate occurs.

In such a case, even if there is no problem with the glass plate used for the previous display, there is a possibility that it will become a problem in the case of the glass plate used in the high-definition display. Based on the above studies, it is considered that the hardness of the minute foreign matter that damages the glass plate is more suitable to be expressed by particle strength than by a representative value based on Mohs hardness.

The average diameter of foreign objects refers to the foreign objects existing on the surface of the spacer paper observed from the thickness direction of the spacer paper, and the long and short diameters of the outer shapes of the foreign objects are measured, which refers to the arithmetic mean of the measured long and short diameters. Examples of foreign substances that can satisfy the particle strength C of 15 MPa or more include SiC, ZrO ₂ , Al ₂ O ₃ , TiO ₂ , SiO ₂ , Fe, Fe ₂ O ₃ , Cr, Ni, CaF ₂ , MgO, and CaCO ₃ . , Al, Cu and other compounds and their alloys, PEEK, PPS, UPE, epoxy resin and other resins, but the particle strength is different even if the composition is the same, so the particle strength must be measured even for the above-mentioned foreign substances.

As a method of reducing the number N (pieces/m ² ) of foreign matter having an average diameter of 10 μm or more and 50 μm or less and a particle strength C of 15 (MPa) or more in the spacer paper, there is a method of using pulp with a small content of foreign matter. , or a method of removing magnets by a magnetic filter, a method of applying centrifugal force to remove tiny ores or dust from pulp, and a method of using a flotation machine to make fine air bubbles absorb and remove foreign matter. In addition, the number N (pieces/m ² ) of the above-mentioned foreign matter can be reduced by taking measures as follows: a method of removing foreign matter contained in the water of the raw material by filtration, etc.; manufacturing steps to prevent the mixing of dust and other methods. As a method of using a pulp with a small amount of foreign matter, there is a method of selecting a pulp with a small amount of ash or a pulp with a small amount of inorganic elements measured by fluorescent X-rays.

The number N (pieces/m ² ) of foreign matter is preferably 10.0 or less, more preferably 5.0 or less, still more preferably 1.0 or less, particularly preferably 0.1 or less, and most preferably 0.01 or less. The lower limit of the number N (pieces/m ² ) of foreign matter is not particularly limited, but is, for example, 1.0×10 ⁻⁶ or more. Even if the above-mentioned measures are taken to prevent foreign matter from entering, it is difficult to completely eliminate foreign matter having an average diameter of 10 μm or more and 50 μm or less and a particle strength C of 15 (MPa) or more.

The number N (pieces/m ² ) of foreign matter can be measured by the following method using a micro-compression tester. For example, the measurement is performed using a laser microscope (manufactured by KEYENCE, VK-8500) and a micro-compression tester (manufactured by Shimadzu Corporation, MCT-510). It can be measured by setting a spacer paper on a stage, and measuring an area of 2 mm x 1.4 mm per field of view in 1600 areas, for example. In this case, automatic measurement can be used for measurement, that is, by using the teaching function of the microscope, the next field of view is measured by moving one field of view for each measurement. Next, the size of the foreign matter in the measurement area is calculated one by one from the number of pixels, and particles with an average diameter of 10 μm or more and 50 μm or less are selected. Place the foreign matter on the stage of the micro-compression testing machine, measure the particle strength C one by one, count the particles whose particle strength C is 15 (MPa) or more, and convert the number N (pieces) of foreign matter per 1 m ² according to the number. /m ² ).

Furthermore, the particle strength C used here is not limited to being measured by a micro-compression tester. For example, it can also be the particle hardness estimated from the indentation depth using a nano-indenter or measured by a micro-Vickers hardness tester. The hardness of the particles.

(arithmetic mean height Sa (μm)) Arithmetic mean height Sa The arithmetic mean height Ra of the series line is extended to the parameter of the surface, which represents the mean of the height of the spacer paper surface and the mean of the absolute value of the difference between the heights of each point. Usually, the arithmetic mean height Sa is used for evaluating the surface roughness.

When the arithmetic mean height Sa of the spacer sheet is large, the smoothness of the spacer sheet tends to decrease. However, if the smoothness of the spacer paper is less than 20 seconds, particles are likely to be generated. By setting the arithmetic mean height Sa of the spacer paper to be at least a certain level and the smoothness to be 20 seconds or more, both the suppression of fine particles and the suppression of damage can be achieved. Therefore, the smoothness of the spacer paper is preferably 20 seconds or more, and the arithmetic mean height Sa of at least one main surface of the spacer paper is preferably 2.5 μm or more, more preferably 3.0 μm or more. If the arithmetic mean height Sa of the spacer sheet is equal to or greater than the above lower limit, foreign matter existing on the spacer sheet tends to be buried, and it can be expected to suppress damage due to pressing of the foreign matter. The upper limit of the arithmetic mean height Sa of the spacer paper is preferably 8.0 μm or less, more preferably 6.0 μm or less, and still more preferably 4.0 μm or less. When the arithmetic mean height Sa is equal to or less than the above upper limit, the generation of fine particles can be suppressed.

Here, among glass substrates, it is the electronic circuit formation surface that is particularly required to suppress adhesion and damage of fine particles. Therefore, among the two main surfaces of the spacer paper, the arithmetic mean height Sa of the main surface on the side in contact with the electronic circuit forming surface of the glass plate is particularly important.

The arithmetic mean height Sa is determined in any area of the spacer paper. For a field of view of 2.0 mm × 1.4 mm, the height information of 20 × 20 fields of view and a total of 400 fields of view are obtained at a distance of 10 mm, which is set as the arithmetic value in each field of view. The average of the average heights. The arithmetic mean height Sa can be measured by a known measuring instrument such as a laser microscope (manufactured by KEYENCE, VK-8500), for example.

(Maximum height Sz(μm)) The maximum height indicates the distance from the highest point to the lowest point on the surface of the separation paper. The maximum height Sz is the height information of 20 × 20 fields of view, a total of 400 fields of view, obtained at a distance of 10 mm for a field of view 2.0 mm × 1.4 mm on the surface of the spacer paper, and is set as the average of the maximum heights in each field of view. The maximum height Sz can be measured, for example, with a known measuring instrument such as a laser microscope (manufactured by KEYENCE, VK-8500).

When the maximum height Sz of the spacer sheet is large, the smoothness of the spacer sheet tends to decrease. However, if the smoothness of the spacer paper is less than 20 seconds, particles are likely to be generated. By setting the maximum height Sz of the spacer paper to a certain value or more and the smoothness to be 20 seconds or more, both the suppression of fine particles and the suppression of damage can be achieved. Therefore, the smoothness of the spacer paper is preferably 20 seconds or more, and the maximum height Sz of at least one main surface of the spacer paper is preferably 45 μm or more, more preferably 50 μm or more. If the maximum height Sz of the spacer paper is more than the above lower limit, foreign matter existing on the spacer paper is likely to be buried, and it can be expected to suppress damage due to the foreign matter pressing on the surface of the spacer paper. In addition, the upper limit of the maximum height Sz of the spacer paper is preferably 80 μm or less, more preferably 65 μm or less, and still more preferably 54 μm or less. When the maximum height Sz is equal to or less than the above-mentioned upper limit, the generation of fine particles can be suppressed.

Here, among glass substrates, it is the electronic circuit formation surface that is particularly required to suppress adhesion and damage of fine particles. Therefore, among the two main surfaces of the spacer paper, the maximum height of the main surface on the side in contact with the electronic circuit forming surface of the glass plate is particularly important.

(Density of spacer paper) The density of spacer paper is the value obtained by dividing the basis weight (g/m ² ) of the spacer paper by the paper thickness (μm). The density of the spacer paper is preferably 0.4 (g/cm ³ ) or more, more preferably 0.5 (g/cm ³ ) or more, still more preferably 0.6 (g/cm ³ ) or more, particularly preferably 0.7 (g/cm ³ ) )above. If the density of the spacer paper is more than the above-mentioned lower limit, since a spacer paper with sufficient strength can be obtained, abnormalities such as paper breakage are less likely to occur during the production process. Moreover, the density of the spacer paper is preferably 1.6 (g/cm ³ ), more preferably 1.4 (g/cm ³ ) or less, still more preferably 1.2 (g/cm ³ ) or less, particularly preferably 1.1 (g/cm 3 ) ³ ) below. If the density of the spacer paper is equal to or less than the above-mentioned upper limit, since there are only a few raw materials, the productivity is improved.

(glass plate laminate) The glass plate laminate of the present embodiment is formed by laminating at least two or more glass plates, and the spacer paper for a glass plate of the present invention is provided between the glass plate and the glass plate.

(glass plate packing body) The glass plate package according to the present embodiment includes a glass plate laminated body and a pallet on which the glass plate laminated body is placed. The glass plate laminated body is formed by laminating at least two or more glass plates. The spacer paper for the glass plate of the present invention is provided between them.

FIG. 3 shows a cross-sectional view of one embodiment of a pallet on which a glass plate is placed. FIG. 4 shows a cross-sectional view of one embodiment of a glass plate package. The glass plate package 10 shown in FIG. 4 includes a glass plate laminate 12 and a pallet. The glass plate laminated body 12 has the spacer paper 16 for glass plates between the glass plate 14 and the other glass plates 14 adjacent thereto. The pallet 30 shown in FIG. 3 is a well-known pallet for glass plate packing, and has a base 22 , an inclined base 18 provided on the upper surface of the base, and a mounting base 24 . The angle θ of the mounting table 24 and the inclined table 18 is not particularly limited as long as the glass plate can be stably stacked, and is preferably 90°.

The angle γ of the inclined table 18 is the angle between the inclined table 18 and the horizontal plane. That is, when the upper surface of the base 22 on which the inclined table 18 and the mounting table 24 are installed is horizontal as shown in FIG. 3 , the angle γ of the inclined table 18 refers to the angle between the inclined table 18 and the base 22 . The closer the angle γ of the inclined table 18 is to 90°, the more space is saved. However, since a large pressure is applied to the end face of the glass plate, there is a possibility of occurrence of defects such as chipping. In addition, the closer the angle γ of the inclined table 18 is to 0°, the more dispersed the pressure applied to the glass plate, and the defects such as chipping of the end face can be suppressed. In this specification, the pallet whose angle of the inclined table is less than 10° is called the pallet of horizontal stacking, and the pallet that exceeds 10° is called the pallet of vertical stacking.

The pallets used can be either horizontal stacking pallets or vertical stacking pallets. In the case of large glass plates, the end of the glass plates will exert greater pressure due to the self-weight of the glass plates. Therefore, in the case of a large-sized glass plate, it is preferable to use a pallet on which the glass plates are placed in a horizontally stacked state. Further, the larger the glass plate is, the greater the pressure applied to the end face of the glass plate. Therefore, the angle of the inclined table is preferably 0° or more and 5° or less, more preferably 0° or more and 3° or less, and more preferably 0°. 1° or less. However, when it is accommodated in a truck or a container for transporting glass plates, there are cases where it cannot be accommodated if it is a pallet that is stacked horizontally. Therefore, in order to save space, pallets stacked vertically can also be used.

A large-sized glass plate refers to, for example, a glass plate with at least one side of 2400 mm or more, and as a specific example, refers to a glass plate of 2400 mm or more on the long side and 2000 mm or more on the short side, for example. The above-mentioned large glass plate is preferably a glass plate with at least one side of 2400 mm or more, such as a glass plate with a long side of 2400 mm or more and a short side of 2100 mm or more, more preferably a glass plate with at least one side of 3000 mm or more, such as a long side. A glass plate with a length of 3000 mm or more and a short side of 2800 mm or more, more preferably a glass plate with at least one side of 3200 mm or more, such as a glass plate with a long side of 3200 mm or more and a short side of 2900 mm or more, preferably at least one side of 3300 mm or more Glass plates with a length of 3,300 mm or more on the long side and 2,950 mm on the short side.

The thickness of the glass plate is preferably 1.30 mm or less. By making the glass plate thinner, since the weight per sheet becomes light, the number of stacked sheets can be increased, and the etching time when producing a liquid crystal panel can be shortened. The thickness of the glass plate of the present invention is more preferably 0.75 mm or less, more preferably 0.65 mm or less, and most preferably 0.55 mm or less. The thickness can also be set to 0.10 mm or less or 0.05 mm or less. Among them, the thickness is preferably 0.10 mm or more, more preferably 0.20 mm or more, from the viewpoint of preventing bending due to its own weight.

The above-mentioned glass plate is preferably used in the manufacture of a display. Since there are fewer particles such as paper dust and foreign matter on the main surface of the glass plate, the surface of the glass plate is less damaged, so the occurrence of defects such as wire breakage can be suppressed. The display is preferably a substrate for a liquid crystal display or an organic EL display. Moreover, since the spacer paper for glass plates of this invention can suppress the damage of a glass plate, when it is used for the case of a high-definition display, its effect is remarkable. Therefore, the glass plate for a display using the spacer paper for a glass plate of the present invention preferably has a pixel count of 2K (1920×1080) or more, more preferably 4K (3840×2160) or more, and more preferably 8K (7680×4320). )above.

As mentioned above, although the spacer paper for glass plates, the glass plate laminated body, and the glass plate packing body have been described in detail, the present invention is not limited to the above-mentioned examples, and of course various improvements can be made without departing from the gist of the present invention. or change. [Example]

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited to these. Hereinafter, Examples 1 to 10 are examples, and Examples 11 to 13 are comparative examples. In addition, in the case where there is no special description, the spacer paper is measured after performing humidity control treatment in a standard state according to JIS P8111:1998. Each measurement of the spacer paper was performed before use as a glass plate laminate.

The smoothness was measured according to JIS P8119:1998 smoothness test method (Baker method) and JIS P8155:010 smoothness test method (Wang Yan formula). It is known that the smoothness of the Wangyan formula is generally higher than that of the Baker method, but since the higher the degree of smoothness of the Baker method, the longer the measurement time, so when it exceeds 100 seconds, the Wangyan formula is used to calculate the smoothness, and the conversion is the value of Baker's method. The smoothness of Example 2, Example 4, Example 6, Example 8, Example 9, Example 12, and Example 13 is the value obtained by calculating the smoothness using Wang Yan's formula and converting it to the value of Beck's method. According to the above method, the smoothness of the spacer sheets produced in Examples 1 to 13 was measured at the approximate center of the first and second principal surfaces of the spacer sheets, and a higher value was set as the smoothness of the spacer sheets. Next, the arithmetic mean height Sa and the maximum height Sz of the principal surface with higher smoothness were measured using a laser microscope (Keyence, VK-8500). The arithmetic mean height Sa and the maximum height Sz are measured at the approximate center of the main surface, respectively.

Sheet resistance was measured using Hiresta-UX and URS probe (MCP-HTP14). Furthermore, in order to keep the probe in an upright state for measurement, a concentric cylindrical load of 600 g was maintained 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 the form of imitating the MCC-A method (measurement on the side of Teflon (registered trademark) side), lay a glass plate with a thickness of 0.5 mm as an insulator on the non-measurement side of the sample, and place the test on it. In this manner, the probe was left still in the approximate center of the measurement surface, and the value after applying a voltage of 1000 V for 10 seconds was taken as the measurement value. In addition, in this measurement, the spacer paper which was left to stand for 15 minutes under the conditions of 23 degreeC and 50% was used. This is intended to simulate the condition of unrolling from the roll surface to the condition before stacking when the spacer paper is actually stacked on the glass substrate. In addition, the measurement surface is the main surface with high smoothness among the 1st main surface and the 2nd main surface of a spacer paper.

Next, the compressive modulus of elasticity of the spacer paper was measured using a constant pressure thickness tester. Next, measure 2.0 mm×1.4 mm of 1,600 areas with a laser microscope and a micro-compression tester, and count 1,600 areas with an average diameter of not less than 10 μm and not more than 50 μm and a particle strength C of 15 (MPa). ) or above the number of foreign objects (pieces), and convert the number N (pieces/m ² ) of foreign objects per 1 m ² according to the number.

The spacer paper for glass plates manufactured in Examples 1 to 13 was formed into a size of 500 mm × 400 mm, and interposed between glass plates with a plate thickness of 0.5 mm and a size of 470 mm × 370 mm, respectively, to form a laminated layer 180. A glass plate laminate of a single glass plate. Furthermore, the overhang margin of each side of the spacer paper is 15 mm. The above-mentioned glass plate is produced by the floating method, the bottom surface is ground with cerium oxide, the two sides of the ground glass plate are subjected to alkali cleaning, and the latter is dried by clean and dry air. The bottom surface is the main surface in contact with molten tin in the glass plate manufactured by the float method. When a glass plate is laminated, the main surface with higher smoothness among the first and second main surfaces of the spacer paper is in contact with the bottom surface of the polished glass plate and laminated. Furthermore, the molding method of the glass plate used in the present invention is not limited to the float method, and may be a down-draw method, a roll-out method, or the like, or an unpolished glass plate.

Each glass plate laminate was placed on a pallet (180 glass plates) stacked horizontally to prepare a glass plate package. Furthermore, the pallet is made of aluminum, and has no vibration-absorbing rubber or spring or other vibration-proof material, and a mechanism for suppressing the vertical movement of the laminated body. The produced glass plate package was subjected to a random vibration test in accordance with JIS Z0232:2004 using a vibration testing machine (manufactured by IMV, m120/MA1), and was subjected to vibration in the vertical direction for 1 hour. Furthermore, the vibration conditions are implemented with an acceleration of 5.92 (m/s ² rms) under the conditions of the acceleration power spectral density of the simulated general transportation environment (mainly roads) described in Table A.1 of the annex to the regulations. The temperature in the environment is 25±2℃ and the humidity is 50±5%.

After the vibration test, take out the glass plate located on the top of the third glass plate from the bottom of the glass plate package, wash the glass plate, and use a foreign object inspection machine to inspect the particle adhesion and damage to the bottom surface of the glass plate. measurement, evaluation.

<Measurement and evaluation of particle adhesion amount and damage on glass plate surface> The bottom surface of the glass plate taken out from the cladding was passed through the bottom surface of the glass plate at a speed of 3 m/min as pure water with 2 lines of piping pressure 1 MPa and flow rate 20 L/min (Ion-exchanged water) flows through the water spray pipe and the spray outlet has a sprayer with uniform fan-shaped nozzles. The cleaning machine is dried by an air knife that sprays clean and dry air to obtain a cleaned substrate. The cleaned substrate was measured in the normal (1.0 μm) mode using a foreign matter inspection machine for FPD (HS-830e manufactured by TORAY ENGINEERING) to obtain the number of particles. Here, at least three pieces were measured for each test condition, and the average value was taken as the number of particles in each test condition. In addition, the particles of the foreign object inspection machine usually include concave damages in addition to the convex attachments. In this specification, the convex attachments are referred to as particles, and the concave defects are referred to as damages.

The adhesion of fine particles was measured using a foreign matter inspection machine for FPD before the production of the layered body and after the vibration was applied, and the difference in the number of fine particles was used for evaluation. The evaluation criteria are as follows. A: The difference in the number of particles is less than 20,000 particles/m ² . B: The difference in the number of particles is 20,000 particles/m ² or more and less than 50,000 particles/m ² . C: The difference in the number of particles is 50,000 particles/m ² or more.

The damage to the glass plate was observed with a foreign matter inspection machine for FPD, and evaluated according to the following evaluation criteria. A: The damage on the bottom surface of the glass plate is less than 0.5/m ² . B: The damage existing on the bottom surface of the glass plate is 0.5 pieces/m ² or more and less than 3.0 pieces/m ² . C: The damage existing on the bottom surface of the glass plate is 3.0 pieces/m ² or more and less than 10.0 pieces/m ² . D: The damage existing on the bottom surface of the glass plate is 10.0 pieces/m ² or more.

(Measurement of compressive elastic modulus K (MPa)) In a constant pressure thickness measuring device (manufactured by TECLOCK, PG-02J), a device equipped with a load mounting part so that the load can be set arbitrarily is used, and the other parts are used unchanged. . Furthermore, the minimum value of thickness reading is 1 μm. First, the thickness of the paper when a load corresponding to the pressure P1 (kPa) is applied to the approximate center of the spacer paper with a diameter of 5 mm of the indenter is set to T1 (μm), and the approximate center of the spacer paper is applied with a pressure equivalent to the pressure P2 ( The paper thickness at the load of kPa) is set as T2, and the (strain amount) = (T1-T2)/T1 (dimensionless) is calculated. Next, (compression elastic modulus K)=(P2-P1)/(strain amount* ^10-3 )(MPa) was calculated|required. In addition, here P1=100 (kPa), P2=270 (kPa). In addition, the compressive elastic modulus was measured by pressing the indenter on the principal surface with the larger smoothness among the first principal surface and the second principal surface of the spacer paper.

(Measurement of the number N (pieces/m ² ) of foreign matter with an average diameter of 10 μm or more and 50 μm or less and a particle strength C of 15 (MPa) or more) The spacer paper was placed on a laser microscope (Keyence, VK- 8500), and fix the ends with tape so that the spacer paper does not float. At the approximate center of the spacer paper, measure 1600 areas of 2.0 mm × 1.4 mm, calculate the size from the number of pixels, and select particles with an average diameter of 10 μm or more and 50 μm or less. For the measurement, automatic measurement can be used, that is, using the teaching function of the microscope, the next field of view is measured by moving the amount of one field of view for each measurement. The particles were placed on a stage of a micro-compression tester (manufactured by Shimadzu Corporation, MCT-510). Furthermore, the micro-compression testing machine uses a diamond flat indenter with a diameter of 50 μm, a test force resolution of 5 μN, and a displacement resolution of 0.01 μm. The outer shape of the particles was confirmed using a microscope attached to the measuring test machine, the major diameter and the minor diameter were measured, and the average diameter was calculated from the arithmetic mean. A test force was applied to the above-mentioned particles with a set limit test force of 20 mN and a load speed of 0.44 mN/sec. The point where the average diameter after compression was 10% smaller than the average diameter before compression was set as the 10% compression point. Using the test force at this time, Cx was calculated using the formula Cx = 2.48 × (test force at 10% compression point)/(average particle size) ² , which is known as the formula for calculating the breaking strength of general particles, and the calculated Cx was set as: is the particle strength C. After that, particles having a particle strength C of 15 (MPa) or more were counted, and the number N (pieces/m ² ) of foreign matter was calculated.

Furthermore, in most cases, a test force greater than 15 (MPa) is applied, and the point where the particles are destroyed (due to the particles being destroyed, the indenter is pressed in suddenly, the test force is roughly constant, and only the point where the displacement changes greatly) is set. As the breaking point, Cs=2.48×(testing force at breaking point)/(average particle size) ² was calculated using the test force at this time, and the calculated Cs was defined as particle strength C.

However, when the Cx calculated by the test force of the 10% compression point is about 15 (MPa), the failure point of the particles cannot be detected. Therefore, in this specification, the test force of the 10% compression point is used to calculate the Cx. Let this value be the particle strength C. In addition, when the breaking point of the particle is observed before reaching the 10% compression point, it is obvious that the particle shape changes greatly at this time point, so the value of Cs is used for the particle strength in this case.

(Example 1) After the pulp slurry of 100% NBKP was beaten with a twin-disc refiner, the raw material slurry was subjected to a fourdrinier wire forming machine at a paper concentration of 1% so that the basis weight was as shown in Table 1. After spraying to form a paper layer, it is passed into a multi-cylinder dryer for drying. As the water of the raw material, pure water treated with a 40 μm filter was used. Then, in the hot soft calendering process, it processed at the temperature of 100 degreeC, and the rolling pressure of 10 (kN/m). The obtained spacer paper had a basis weight of 45.1 g/m ² , a thickness of 80 μm, a density of 0.53 (g/cm ³ ), a smoothness of the first main surface of 25 seconds, and a smoothness of the second main surface of 23 seconds.

(Example 2) A spacer paper was obtained in the same manner as in Example 1, except that a temperature gradient was applied at a temperature of 150° C. in the hot soft calendering treatment, and a thermal gradient treatment was performed at a calendering pressure of 120 (kN/m).

(Example 3) The composition of the raw material adopts the NBKP shown in Example 1 as 50%, the LBKP(A) as 50%, the water filter with an opening diameter of 20 μm, and a hard calendering treatment. A spacer paper was obtained in the same manner as in Example 1, except that it was calendered and processed at a calendering pressure of 30 (kN/m).

(Example 4) Using the raw material system including the pulp and water shown in Example 3, the temperature was 150°C and the rolling pressure was 150 (kN/m) in the calendering treatment, except that the same procedure as in Example 1 was carried out. way to get spacer paper.

(Example 5) A spacer paper was obtained in the same manner as in Example 3, except that a filter with an opening diameter of 5 μm was used, and the rolling pressure was 50 (kN/m).

(Example 6) The raw material system containing the pulp and water shown in Example 5 was used, and after cooling treatment with water and low-temperature blast before the calendering treatment, the calendering treatment was carried out at a temperature of 200°C and a rolling pressure of 170 (kN /m), except that a spacer paper was obtained in the same manner as in Example 1.

(Example 7) A spacer paper was obtained in the same manner as in Example 1, except that the raw material slurry was dried with a Yankee dryer and not subjected to calendering after papermaking.

(Example 8) The composition of the raw materials was obtained in the same manner as in Example 4, except that the NBKP shown in Example 1 was set to 50%, the LBKP (B) was set to 50%, and the water filter was used with an opening diameter of 40 μm. spacer paper. Furthermore, LBKP(A) and LBKP(B) are hardwood bleached kraft pulps derived from woods of different origins.

(Example 9) A spacer paper was obtained in the same manner as in Example 6, except that the papermaking speed was slowed down by 20%, and a drying roller at 150° C. was set for drying treatment before winding the spacer paper to reduce the water content.

(Example 10) A spacer paper was obtained in the same manner as in Example 1, except that the moisture content was increased by performing humidification treatment before winding up the spacer paper.

(Example 11) A spacer paper was obtained in the same manner as in Example 1, except that the calendering treatment was not performed after the raw material slurry was made into paper.

(Example 12) Using the raw material system including the pulp and water shown in Example 8, using the raw material pulp beaten with a freeness of 200 mL of CSF to make paper, use a moisture imparting device to make wet paper, and press 200 kN at a temperature of 150 ° C and 200 kN. Under the condition of /m, 10 stages of super calendering treatment were performed to obtain spacer paper as cellophane paper.

(Example 13) Using the raw material system including the pulp and water shown in Example 3, the papermaking speed was slowed down by 20%, and the calendering treatment was carried out at a temperature of 100 ° C and a rolling pressure of 350 kN/m. Spacer paper is obtained in the same manner.

[Table 1] example Basis weight (g/m ² ) Thickness (μm) Density (g/cm ³ ) Smoothness (seconds) Sheet resistance (Ω/□) Compression modulus of elasticity (MPa) Number of foreign objects N (pieces/m ² ) Hard foreign body resistance value Sa (μm) Sz (μm) particle adhesion Injury 1 45.1 79 0.57 25 6.7E+12 3.6 2.8 10.1 3.9 61 B A 2 41.7 71 0.59 120 9.3E+12 2.9 2.5 7.3 3.4 51 A A 3 55.2 77 0.72 39 9.1E+11 5.3 1.5 8.0 4.2 55 B A 4 49.8 62 0.80 180 5.5E+12 7.4 1.6 11.8 3.0 48 A A 5 68.5 76 0.90 65 7.3E+12 8.1 0.9 7.3 4.0 54 A A 6 62.3 70 0.89 330 6.2E+11 7.8 0.3 2.3 2.5 45 A A 7 49.8 75 0.66 90 4.4E+12 3.4 3.6 12.2 3.1 55 A A 8 51.0 62 0.82 210 8.1E+12 7.5 4.4 33.0 2.9 49 A B 9 70.8 66 1.07 350 6.9E+13 8.2 0.7 5.7 2.2 42 A A 10 45.7 80 0.57 twenty three 4.5E+10 2.3 3.0 6.9 3.7 55 B A 11 49.2 89 0.55 13 1.6E+13 3.9 3.3 12.9 4.7 58 C A 12 55.8 41 1.36 520 7.5E+11 9.6 4.8 46.1 2.4 45 A D 13 76.5 66 1.16 200 2.1E+11 9.4 3.8 35.7 2.3 44 A C

＜Results＞ Table 1 shows the measurement results and evaluation results. According to Table 1, when the smoothness was 20 seconds or more, the adhesion of the fine particles was all A or B. On the other hand, when the smoothness was less than 20 seconds, the adhesion amount of the fine particles was all C. In addition, when the compressive elastic modulus K was 8.5 MPa or less, all the damage properties were A or B. On the other hand, when the compressive elastic modulus K exceeds 8.5 MPa, the damage property is C or D.

This application is based on Japanese Patent Application No. 2020-195392 filed on November 25, 2020 and Japanese Patent Application No. 2021-187432 filed on November 17, 2021, the contents of which are incorporated herein by reference.

10: Glass plate packing body 12: Glass plate laminate 14: glass plate 16: Spacer paper for glass plates 18: Tilt table 22: Abutment 24: Mounting table 30: pallet 42: Spacer paper roll 100: Manufacturing device of spacer paper for glass plate 112: Headbox 114: Line Department 116: Offline 118: Online 120: Pressurizing part 124: Drying section 126: Calendering part 128: Reel 130: Large reel 134: Cutter 136: Winder

FIG. 1 is a graph showing the relationship between Mohs hardness and particle strength. It is a conceptual diagram which shows one Embodiment of the manufacturing method of the spacer paper for glass plates. FIG. 3 is a cross-sectional view showing one embodiment of a pallet on which a glass plate is placed. Fig. 4 is a cross-sectional view showing one embodiment of a glass plate package.

10: Glass plate packing body

12: Glass plate laminate

14: glass plate

16: Spacer paper for glass plates

18: Tilt table

22: Abutment

24: Mounting table

Claims (10)

A spacer paper for glass plates, the thickness of which is not less than 30 μm and not more than 150 μm, The smoothness of at least one main surface of the spacer paper for a glass plate is 20 seconds or more, The compressive elastic modulus K measured on the main surface is 1.0 MPa or more and 8.5 MPa or less. The spacer paper for a glass plate according to claim 1, wherein the arithmetic mean height Sa of the main surface is 2.5 μm or more. The spacer paper for a glass plate according to claim 1 or 2, wherein the maximum height Sz of the main surface is 45 μm or more. The spacer paper for a glass plate according to any one of Claims 1 to 3, wherein the density of the spacer paper for a glass plate is 0.4 (g/cm ³ ) or more and 1.6 (g/cm ³ ) or less, and the smoothness of the main surface is More than 20 seconds and less than 400 seconds. The spacer paper for glass plates according to any one of claims 1 to 4, wherein the sheet resistance of the spacer paper for glass plates is 5.0×10 ¹⁰ (Ω/□) or more and 5.0×10 ¹³ (Ω/□) or less. The spacer paper for glass plates according to any one of claims 1 to 5, wherein the compressive elastic modulus K (MPa) and the average diameter contained in the spacer paper for glass plates are 10 μm or more and 50 μm or less and have particle strength C is the product of the number N (pieces/m ² ) of foreign objects of 15 (MPa) or more, that is, the hard foreign object resistance value KN is 35.0 or less. The spacer paper for glass plates according to any one of claims 1 to 6, wherein the compressive elastic modulus K (MPa) and the average diameter contained in the spacer paper for glass plates are 10 μm or more and 50 μm or less and have particle strength C is the product of the number N (pieces/m ² ) of foreign objects of 15 (MPa) or more, that is, the hard foreign object resistance value KN is 15.0 or less. The spacer paper for a glass plate according to any one of claims 1 to 7, wherein the main surface is a surface in contact with the electronic circuit forming surface of the glass plate. A glass plate laminate, which is formed by laminating at least two or more glass plates, the glass plate laminate having the spacer paper for a glass plate according to any one of claims 1 to 8 between the glass plate and the glass plate . A glass plate package comprising the glass plate laminate according to claim 9, and a pallet on which the glass plate laminate is placed.

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