Glass plate laminate and glass plate package

Abstract

The invention relates to a glass plate laminate and a glass plate package. The glass plate laminate is to be housed in a housing container, and the glass plate laminate has a structure in which a plurality of glass plates and a plurality of glass plate interleaving paper are alternately laminated. A color value in an L * a * b * color system of an in-plane region of the glass plate interleaving paper located closest to one side of the glass plate laminate in the first direction is set as a first in-plane color. When a color value in an L * a * b * color system in an in-plane region of the glass plate interleaving paper located closest to one side of the glass plate laminate in the second direction is a second in-plane color, a color difference [Delta] E * ab between the first in-plane color and the second in-plane color is equal to or less than a predetermined value.

Description

Technical Field

[0001] The present invention relates to a glass plate laminate and a glass plate package. Background Art

[0002] For glass plates with circuits etc. assembled on their surfaces, such as alkali-free glass plates used in liquid crystal displays, even slight scratches or contamination on their surfaces may cause disconnection and poor pattern formation. Therefore, such glass plates require extremely high surface properties. Therefore, as a method for preventing scratches and contamination of glass plates during storage and transportation, a method of separating the surfaces of adjacent glass plates by inserting glass plate backing paper (hereinafter also referred to as "backing paper") between stacked glass plates has been used in the past.

[0003] The form in which the lining paper is sandwiched between the glass plates is called a glass plate laminate. The glass plate laminate is stored in a storage container such as a pallet, and the pallet has a lining paper pressing member (lateral pressing member) that presses the lining paper extending from the side of the glass plate laminate from the side. The form in which the glass plate laminate is stored in the storage container is called a glass plate package.

[0004] In the method of sandwiching the backing paper between the glass plates, the backing paper is in direct contact with the surface of the glass plate. Therefore, various foreign matters such as paper powder generated from the backing paper, resin components or adhesive components contained in the backing paper raw material, fillers added in the papermaking process, additives such as pH adjusters, and component pieces mixed in the process may exist on the surface of the backing paper, and be transferred to the surface of the contacted glass plate and detected as particles. If there are many particles on the glass plate, it may cause a problem such as disconnection of fine wiring formed on the surface of the glass plate.

[0005] For example, Patent Document 1 states that in a glass plate packaging body that includes a glass plate stack obtained by stacking multiple glass plates with backing paper, transfer contamination from the backing paper to the glass plates can be suppressed by making the content of higher saturated fatty acids in the backing paper less than 0.08% by mass relative to the mass of the backing paper.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: International Publication No. 2011 / 118502 Summary of the invention

[0009] Problems to be solved by the invention

[0010] However, when the interleaving paper described in Patent Document 1 is used, particles on the surface of the glass plate may be detected, and this may be insufficient from the viewpoint of suppressing particles.

[0011] In view of the above circumstances, an object of the present invention is to provide a glass plate laminate capable of suppressing particles on the surface of a glass plate, and a glass plate package including the glass plate laminate.

[0012] Means used to solve problems

[0013] The present inventors have found that when using a glass plate interleaving paper that changes color due to aging with light, particles are easily generated on the surface of the glass plate, thereby completing the present invention.

[0014] That is, the present invention provides the following glass plate laminated body and glass plate package.

[0015] <1> A glass plate stack, the glass plate stack being a glass plate stack to be stored in a storage container, wherein the glass plate stack has a structure in which a plurality of glass plates and a plurality of glass plate backing papers are alternately stacked, the glass plate backing papers are backing papers containing virgin pulp, a direction away from the storage container in the stacking direction of the glass plate stack is set as a first direction, a direction opposite to the first direction is set as a second direction, a main surface of the glass plate backing paper on the first direction side is set as a first main surface, an area of ​​the glass plate backing paper that contacts or corresponds to a main surface of an adjacent glass plate on the first main surface is set as an in-plane area, and the in-plane area of ​​the glass plate backing paper that is closest to the glass plate stack in the first direction is set at L ＊ a ＊ b ＊ The color value in the colorimetric system is set as the first in-plane color, and the in-plane region of the glass plate interleaving paper which is located closest to the second direction side of the glass plate laminated body in the glass plate laminated body is set at L ＊ a ＊ b ＊ The color value in the color system is set as the second surface color. At this time, the color difference ΔE between the first surface color and the second surface color is ＊ ab Below 0.58.

[0016] <2> A glass plate stack, the glass plate stack being a glass plate stack to be stored in a storage container, wherein the glass plate stack has a structure in which a plurality of glass plates and a plurality of glass plate backing papers are alternately stacked, the glass plate backing papers are backing papers containing waste paper pulp, a direction away from the storage container in the stacking direction of the glass plate stack is set as a first direction, a direction opposite to the first direction is set as a second direction, a main surface of the glass plate backing paper on the first direction side is set as a first main surface, an area of ​​the first main surface of the glass plate backing paper that contacts or corresponds to a main surface of an adjacent glass plate is set as an in-plane area, and the in-plane area of ​​the glass plate backing paper that is closest to the first direction side of the glass plate stack in the glass plate stack is set at L ＊ a ＊ b ＊ The color value in the colorimetric system is set as the first in-plane color, and the in-plane region of the glass plate interleaving paper which is located closest to the second direction side of the glass plate laminated body in the glass plate laminated body is set at L ＊ a ＊ b ＊ The color value in the color system is set as the color in the second plane. At this time, the color difference ΔE between the color in the first plane and the color in the second plane is ＊ ab Below 5.0.

[0017] <3> A glass plate package, comprising: the glass plate stack according to <1> or <2>; and a storage container for storing the glass plate stack, wherein the glass plate stack is placed with the surface of the glass plate stack on the second direction side facing the storage container.

[0018] Effects of the Invention

[0019] According to the present invention, it is possible to provide a glass plate laminate that can suppress particles on the surface of a glass plate by suppressing aging discoloration of an interleaving paper for a glass plate, and a glass plate package having the glass plate laminate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a side view showing one form of the glass plate laminated body according to the present embodiment.

[0021] Figure 2 To represent the composition Figure 1 The exploded perspective view of a part of the glass plate laminated body shown is a laminated state of the interleaving paper for glass plates and the adjacent glass plates.

[0022] Figure 3 To represent the composition Figure 1The exploded perspective view of a part of the glass plate laminated body shown is a laminated state of the interleaving paper for glass plates and the adjacent glass plates.

[0023] Figure 4 This is a side view showing another form of the glass sheet laminated body according to the present embodiment.

[0024] Figure 5 To represent the composition Figure 2 The exploded perspective view of a part of the glass plate laminated body shown is a laminated state of the interleaving paper for glass plates and the adjacent glass plates.

[0025] Figure 6 It is a side view which shows the schematic structure of an example of a glass plate package.

[0026] Figure 7 It is a side view which shows the schematic structure of another example of a glass plate package.

[0027] Figure 8 This is a diagram showing the measurement results of the number of particles after the loading test using the interleaving paper A for glass plates.

[0028] Fig. 9 This is a diagram showing the measurement results of the number of particles after the loading test using the interleaving paper B for glass plates.

[0029] DESCRIPTION OF SYMBOLS 1, 1aa, 1a, 1b, 1N Glass plate backing paper 1aa1, 1a1, 1N1 First main surface 1aa2, 1a2, 1N2 Second main surface 1aa1A, 1a1A, 1N1A In-plane area 1aa1B, 1a1B, 1N1B Projection margin area 2, 2a, 2b, 2N Glass plate 1aa2A Contact area 1aa2B Non-contact area 10 Glass plate laminate 22 Back plate 30 Glass plate package 31 Pallet 32 ​​Back plate 33 Base 34 Bottom plate 50 Glass plate package 51 Pallet 52 Back plate 53 Base 54 Pillar D1 First direction D2 Second direction DETAILED DESCRIPTION

[0030] Hereinafter, the present invention will be described in detail, but the present invention is not limited to the following embodiments and can be implemented in any deformed manner without departing from the gist of the present invention. In addition, the " to " indicating a numerical range is used to include the numerical values ​​recorded before and after it as the meaning of the lower limit and the upper limit.

[0031] In addition, in the following drawings, the same reference numerals are sometimes used to mark components / parts that play the same role and are described, and repeated descriptions are sometimes omitted or simplified. In addition, the embodiments described in the drawings are schematically illustrated for the purpose of clearly describing the present invention, and do not necessarily accurately represent actual dimensions and scales.

[0032] (Glass Plate Laminate)

[0033] The glass plate stack involved in the present embodiment is a glass plate stack to be stored in a storage container, the glass plate stack having a structure in which a plurality of glass plates and a plurality of glass plate backing papers are alternately stacked, a direction away from the storage container in the stacking direction of the glass plate stack is set as a first direction, a direction opposite to the first direction is set as a second direction, a main surface of the glass plate backing paper on the first direction side is set as a first main surface, an area of ​​the glass plate backing paper that contacts or corresponds to the main surface of the adjacent glass plate on the first main surface is set as an in-plane area, and the in-plane area of ​​the glass plate backing paper that is closest to the glass plate stack in the first direction side is set at L ＊ a ＊ b ＊ The color value in the colorimetric system is set to the first in-plane color, and the in-plane region of the glass plate interleaving paper located closest to the second direction side of the glass plate laminated body is set to L ＊ a ＊ b ＊ The color value in the color system is set as the second surface color. At this time, the color difference ΔE between the first surface color and the second surface color is ＊ ab is below the specified value.

[0034] First, refer to Figure 1 to Figure 3 , a glass plate laminate according to one embodiment (embodiment 1) of the present embodiment will be described.

[0035] Figure 1 1 is a side view showing a glass plate laminate according to Embodiment 1. Figure 1 As shown, the glass plate stack 10 in this embodiment is placed on the surface (placing surface) of the back plate 22 of the storage container and is to be stored in the storage container. The glass plate stack 10 in this embodiment has a structure in which N glass plates 2 and N glass plate backing papers 1 are alternately stacked. Here, N is an integer greater than 2.

[0036] In addition, when the direction perpendicular to the surface (placing surface) of the back plate 22 of the storage container is set as the stacking direction of the glass plate stack 10, the direction away from the storage container is set as the first direction D1, and the direction opposite to the first direction D1 is set as the second direction D2, the glass plate backing paper 1 closest to the first direction D1 is set as the glass plate backing paper 1a, the second glass plate backing paper counted from the side closest to the first direction D1 is set as the glass plate backing paper 1b, and the glass plate backing paper 1 closest to the second direction D2 is set as the glass plate backing paper 1N. It should be noted that the glass plate backing paper 1N is the Nth glass plate backing paper 1 counted from the glass plate backing paper 1a, and a total of N glass plate backing papers 1 are included in the glass plate stack 10. When N is 2, the glass plate backing paper 1b is equivalent to the glass plate backing paper 1N.

[0037] In addition, the glass plate 2 closest to the first direction D1 is referred to as glass plate 2a, the second glass plate from the side closest to the first direction D1 is referred to as glass plate 2b, and the glass plate 2 closest to the second direction D2 is referred to as glass plate 2N. It should be noted that glass plate 2N is the Nth glass plate 2 counted from glass plate 2a, and a total of N glass plates 2 are included in the glass plate laminate 10. When N is 2, glass plate 2b corresponds to glass plate 2N.

[0038] In this embodiment, a glass plate 2a is stacked on the outermost surface of the glass plate stack 10 on the first direction D1 side, and a glass plate backing paper 1N is stacked on the outermost surface of the glass plate stack 10 on the second direction D2 side. The glass plate backing paper 1N is placed on the placement surface of the back plate 22 of the storage container.

[0039] In addition, regarding each glass plate interleaving paper 1, the principal surface on the first direction side D1 is set as the first principal surface, and the principal surface on the second direction D2 side, that is, the principal surface opposite to the first principal surface is set as the second principal surface. The glass plate interleaving paper 1a positioned closest to the first direction D1 side has: a first principal surface 1a1 on the first direction D1 side; and a second principal surface 1a2 on the second direction D2 side. Similarly, the glass plate interleaving paper 1N positioned closest to the second direction D2 side has: a first principal surface 1N1 on the first direction D1 side; and a second principal surface 1N2 on the second direction D2 side.

[0040] Next, the in-plane area and the protruding margin area of ​​the first main surface of the glass plate backing paper in the glass plate laminate of this embodiment (embodiment 1) are described. In this embodiment, the area of ​​the first main surface of the glass plate backing paper 1 that contacts the main surface of the adjacent glass plate 2 is defined as the in-plane area. Figure 21 is an exploded perspective view showing the stacked state of the glass plate interleaving paper 1a located closest to the first direction D1 side and the glass plate 2a adjacent to the first main surface 1a1 side of the glass plate interleaving paper 1a in the glass plate stack 10 of embodiment 1. Figure 2 As shown in FIG. 1 , the in-plane area 1a1A of the first main surface 1a1 of the glass plate backing paper 1a can be defined as the area of ​​the first main surface 1a1 where the glass plate backing paper 1a and the adjacent glass plate 2a overlap (contact) with each other. In addition, in the present embodiment, the area of ​​the first main surface 1a1 of the glass plate backing paper 1a other than the in-plane area 1a1A is defined as the protruding margin area 1a1B. Figure 2 In the figure, the protruding margin region 1a1B may be referred to as a region on the first main surface 1a1 of the interleaving paper 1a for glass plates where the glass plate 2a does not overlap (contact) with the interleaving paper 1a for glass plates.

[0041] Similarly, the in-plane region 1N1A and the protruding margin region 1N1B of the first main surface 1N1 of the interleaving paper 1N for a glass plate located closest to the one side in the second direction will be described. Figure 3 1 is an exploded perspective view showing the stacked state of the glass plate interleaving paper 1N located closest to the second direction D1 side and the glass plate 2N adjacent to the first main surface 1N1 side of the glass plate interleaving paper 1N in the glass plate stack 10 of embodiment 1. Figure 3 As shown, the in-plane region 1N1A of the first main surface 1N1 of the glass plate backing paper 1N can be defined as the region of the first main surface 1N1 where the glass plate backing paper 1N and the adjacent glass plate 2N overlap (contact) each other. In addition, in the present embodiment, the region of the first main surface 1N1 of the glass plate backing paper 1N other than the in-plane region 1N1A is defined as the protruding margin region 1N1B. Figure 3 In the figure, the protruding margin region 1N1B may be referred to as a region on the first main surface 1N1 of the interleaving paper 1N for glass plates where the glass plate 2N does not overlap (contact) with the interleaving paper 1N for glass plates.

[0042] In addition, refer to Figures 4-5 , a glass plate laminate according to one embodiment (embodiment 2) of the present embodiment will be described.

[0043] Figure 4 2 is a side view of a glass sheet laminate according to Embodiment 2. Figure 4 As shown, the glass plate laminate 10 in this embodiment is placed on the back plate 22 of the storage container and stored in the storage container. The glass plate laminate 10 in this embodiment has a structure in which N glass plates 2 and N+1 glass plate interleaving papers 1 are alternately stacked. Here, N is an integer greater than 2.

[0044] In addition, when the direction perpendicular to the surface (placing surface) of the back plate 22 of the storage container is set as the stacking direction, the direction away from the storage container is set as the first direction D1, and the direction opposite to the first direction D1 is set as the second direction D2, the glass plate backing paper 1 on the side closest to the first direction D1 is set as the glass plate backing paper 1aa. In addition, the second glass plate backing paper counted from the side closest to the first direction D1 is set as the glass plate backing paper 1a, the third glass plate backing paper counted from the side closest to the first direction D1 is set as the glass plate backing paper 1b, and the glass plate backing paper 1 on the side closest to the second direction D2 is set as the glass plate backing paper 1N. It should be noted that the glass plate backing paper 1N is the Nth glass plate backing paper counted from the glass plate backing paper 1a, and the glass plate stack 10 includes: a total of N+1 glass plate backing papers 1 together with the glass plate backing paper 1aa. When N is 2, the interleaving paper 1b for glass plates corresponds to the interleaving paper 1N for glass plates.

[0045] In addition, the glass plate 2 closest to the first direction D1 is referred to as glass plate 2a, the second glass plate from the side closest to the first direction D1 is referred to as glass plate 2b, and the glass plate 2 closest to the second direction D2 is referred to as glass plate 2N. It should be noted that glass plate 2N is the Nth glass plate 2 counted from glass plate 2a, and a total of N glass plates 2 are included in the glass plate laminate 10. When N is 2, glass plate 2b corresponds to glass plate 2N.

[0046] In this embodiment, a glass plate backing paper 1aa is stacked on the outermost surface of the glass plate stack 10 on the first direction D1 side, and a glass plate backing paper 1N is stacked on the outermost surface of the glass plate stack 10 on the second direction D2 side. The glass plate backing paper 1N is placed on the placement surface of the back plate 22 of the storage container.

[0047] In addition, regarding each glass plate interleaving paper 1, the principal surface on the first direction side D1 is set as the first principal surface, and the principal surface on the second direction D2 side, that is, the principal surface opposite to the first principal surface is set as the second principal surface. The glass plate interleaving paper 1aa located closest to the first direction D1 side has a first principal surface 1aa1 located on the first direction D1 side, and a second principal surface 1aa2 located on the second direction D2 side. Similarly, the glass plate interleaving paper 1N located closest to the second direction D2 side has a first principal surface 1N1 located on the first direction D1 side, and a second principal surface 1N2 located on the second direction D2 side.

[0048] Next, the in-plane area and the protruding margin area of ​​the first main surface of the glass plate backing paper in the glass plate laminate of the present embodiment (method 2) are described. In the present embodiment, for the glass plate backing paper 1aa located closest to the first direction D1 side, the area of ​​the first main surface corresponding to the main surface of the adjacent glass plate 2a is defined as the in-plane area. Figure 5 The details are explained below.

[0049] Figure 5 It is an exploded perspective view showing a stacked state of the interleaving paper 1aa for glass plates located closest to the first direction D1 side in the glass plate laminated body 10 of the present embodiment and the glass plates 2a adjacent to the interleaving paper 1aa for glass plates.

[0050] The glass plate backing paper 1aa and the glass plate 2a are stacked in such a manner that the second main surface 1aa2 of the glass plate backing paper 1aa is in contact with the glass plate 2a. Here, the area in the second main surface 1aa2 of the glass plate backing paper 1aa that is in contact with the main surface of the glass plate 2a is defined as the contact area 1aa2A, and the area that is not in contact with the main surface of the glass plate 2a is defined as the non-contact area 1aa2B. Furthermore, when the glass plate backing paper 1aa is viewed from the stacking direction, the area in the first main surface 1aa1 that overlaps with the contact area 1aa2A of the opposite second main surface 1aa2 is defined as the area corresponding to the main surface of the glass plate 2a, that is, the in-plane area 1aa1A. In addition, the area of ​​the first main surface 1aa1 other than the in-plane area 1aa1A is defined as the protruding margin area 1aa1B. In addition, the protruding margin area 1aa1B may be referred to as an area overlapping with the non-contact area 1aa2B in the second main surface 1aa2 when the interleaving paper 1aa for glass plates is viewed in plan from the lamination direction.

[0051] In the present embodiment, regarding the glass plate backing paper 1N located closest to the second direction side, the region in contact with the main surface of the adjacent glass plate 2N on the first main surface 1N1 of the glass plate backing paper 1N is defined as the in-plane region, similarly to the above-described embodiment 1. In addition, the region other than the in-plane region 1N1A on the first main surface 1N1 of the glass plate backing paper 1N is defined as the protruding margin region 1N1B.

[0052] It should be noted that, in the above-mentioned methods 1 and 2, the glass plate stack is stored in a manner in which a backing paper for the glass plate is placed on the surface (placing surface) of the back plate of the storage container, but the present embodiment is not limited to this, and the glass plate stack may also be stored in a manner in which the glass plate is placed on the surface (placing surface) of the back plate of the storage container.

[0053] The inventors of the present invention have discovered that when using backing paper for glass plates that has aged and discolored due to light, particles are easily generated on the surface of the glass plates, thereby completing the present invention. As a reason for this, it is believed that when the backing paper for glass plates has aged and discolored due to light, the amount of paper powder generated from the backing paper increases, or the amount of foreign matter that falls off increases. It should be noted that in this specification, particles refer to convex attachments, and when there are paper powders or foreign matter on the surface of the glass plate, they are detected by measurement based on a foreign matter inspection machine. Particles are generated, for example, by transferring paper powders or foreign matter generated from the backing paper for glass plates to the glass plates.

[0054] "Aging discoloration" refers to the deterioration of paper caused by light, which is typically accompanied by discoloration of the paper. Specifically, it is known that the resin component (mainly lignin) contained in the paper undergoes chemical changes due to sunlight (ultraviolet rays), thereby becoming yellow to brown. Therefore, in this specification, the degree of aging discoloration is evaluated by the color value of the backing paper for glass plates. It should be noted that, usually for paper, most of the evaluations are based on ISO whiteness indicating whiteness, but in the case of aging discoloration, since yellowing occurs, it is considered that in order to accurately indicate the degree of its change, an evaluation based on color value is more appropriate. By the way, the expression "aging discoloration" is sometimes also used as a term to indicate the discoloration of glass caused by backing paper for glass plates (the adhesion of foreign matter from the paper, the reaction of components or moisture on the surface of the paper with components in the glass to produce blurring caused by products, etc.), but here, aging discoloration refers to the deterioration of the paper itself.

[0055] The in-plane area of ​​the glass plate backing paper located closest to the second direction side of the glass plate stack (also referred to as the "bottom" for convenience) is usually not exposed to light, and is therefore considered to remain undyed and undiscolored. Specifically, the inventors have confirmed that when a glass plate stack comprising 100 glass plates is irradiated with 10,000 Lux of light, which is greater than the light received near the window glass in the house, the illumination near the bottom glass plate backing paper is about 0.01% to about 0.05%, and is basically shielded from light. It can be said that when the glass plate stack is loaded on a so-called vertical type pallet as one form of a storage container, the same is true near the center of the in-plane area at the bottom (the back side).

[0056] In addition, the protruding margin area of ​​the interleaving paper for glass plates which is located closest to the second direction one side (lowermost portion) of the glass plate laminated body is exposed to light and may be discolored due to aging.

[0057] In contrast, the backing paper for the glass plate located closest to the first direction side of the glass plate laminate (also referred to as the "uppermost" for convenience) is easily exposed to light and prone to aging discoloration. Therefore, it can be said that when the color difference between the backing paper at the upper and lower ends of the glass plate laminate (the backing paper closest to the first direction side and the backing paper closest to the second direction side) is large, the degree of aging discoloration of the backing paper on the uppermost side (closest to the first direction side) is large. In this regard, if the color difference ΔE between the color within the first surface and the color within the second surface is ＊ ab When the value is equal to or less than a predetermined value, the aging discoloration of the interleaving paper on the uppermost side (the side closest to the first direction) is suppressed, and therefore particles on the surface of the glass plate are suppressed for the entire glass plate laminate.

[0058] In this specification, the color difference of the backing paper at the upper and lower ends of the glass plate laminate is calculated based on the color difference between the first surface color and the second surface color. That is, when the direction away from the storage container in the stacking direction of the glass plate laminate is set as the first direction, and the direction opposite to the first direction is set as the second direction, the in-plane area of ​​the backing paper for the glass plate located closest to the first direction side of the glass plate laminate is set at L ＊ a ＊ b ＊ The color value in the colorimetric system is defined as the first in-plane color. In addition, the in-plane region of the glass plate interleaving paper located closest to the second direction side of the glass plate laminate is defined as L ＊ a ＊ b ＊ The color value in the color system is set to the color in the second plane.

[0059] The color value of the interleaving paper for glass plates can be measured by the method described in the examples described below. The color value of the in-plane region is measured at a region located 20% or more inside from the end of each side of the outer shape of the in-plane region.

[0060] Here, when the ash content of the glass plate interleaving paper is 0.001% to 0.5%, the color difference ΔE between the first surface color and the second surface color is ＊ ab It is 0.58 or less, preferably 0.57 or less, and more preferably 0.56 or less.

[0061] In addition, when the ash content of the glass plate interleaving paper is greater than 0.5% and less than or equal to 10%, the color difference ΔE between the first surface color and the second surface color is ＊ ab It is 5.0 or less, preferably 4.5 or less, and more preferably 4.0 or less.

[0062] For waste paper pulp, hard foreign matter such as sand and metal is mixed in when the waste paper is recycled, or more fillers, additives, cleaning agents, etc. are used to improve cleanliness and whiteness. Therefore, compared with virgin paper, there is a tendency for the ash content to become higher. The backing paper for glass plates with an ash content of more than 0.001% and less than 0.5% is equivalent to the backing paper containing virgin pulp, and the backing paper for glass plates with an ash content greater than 0.5 and less than or equal to 10% is equivalent to the backing paper containing waste paper pulp. In order to make the ash content less than 0.001%, it is necessary to select excessive pulp, and the productivity is significantly deteriorated. In addition, when the ash content is greater than 10%, the amount of impurities is large, so it is easy to produce scratches and particles on the glass plate, which is not suitable as a backing paper for glass plates. Backing paper containing virgin pulp is mostly cleaner, and is preferred from the perspective of reducing particles on the surface of the glass plate. On the other hand, from the perspective of productivity, required quality, etc., it is sometimes preferred to use backing paper containing waste paper pulp. In this embodiment, the color difference ΔE is adjusted according to the ash content of the glass plate interleaving paper. ＊ ab By setting it to the above-mentioned value or less, in any case, the adhesion of particles due to deterioration discoloration can be relatively suppressed.

[0063] The inventors have found that aging discoloration is the cause of the increase in particles, but have also found that when the degree of aging discoloration is relatively mild, particles can sometimes be suppressed. That is, the color difference ΔE between the color of the first surface and the color of the second surface is ＊ abIt can be 0, but in the case of being greater than 0, particles can sometimes be further suppressed. As a reason for this, it is believed that the backing paper for glass plates receives light moderately, thereby reducing the shedding of paper dust and foreign matter. According to the inventor's research, when the backing paper for glass plates retains water to the extent of condensation, the particles become very many, while on the other hand, when the water retention is moderately high, such as about 8% to about 12%, the particles decrease. It is believed that when the water retention is excessive, water penetrates between fibers and between foreign matter and fibers, and is freed into water, or the resin component with a hydrophilic group dissolves in water, resulting in more particles. Generally, the water retention of paper is affected by additives in the paper and the humidity of the environment. In particular, in the case of backing paper without additives to increase water retention, the water retention is about 5% to about 7% under the conditions of 25°C and 50RH%. It is believed that when the water retention is moderately increased, a small amount of water molecules enter between the cellulose constituting the fibers and between cellulose and foreign matter to form hydrogen bonds more firmly, so the shedding of paper dust and foreign matter is reduced. It is believed that the glass plate backing paper is heated / humidified by receiving moderate light to a degree that does not damage it, which promotes the moisture retention of the paper. When the bonds between fibers and even between fibers and foreign matter become temporarily strong, even if there is a cycle of moisture absorption and release of the paper that changes within a day, the bonds will not separate within a certain range, so the shedding of paper powder, foreign matter, etc. is reduced. It is believed that when light is further irradiated, the fibers are damaged, the bonds between the fibers are broken, and shedding is dominant. When the ash content of the glass plate backing paper is 0.001% to 0.5%, the color difference ΔE between the color inside the first surface and the color inside the second surface is ＊ ab is 0 or more, preferably 0.2 or more, and more preferably 0.3 or more. In addition, when the ash content of the glass plate interleaving paper is greater than 0.5% and less than or equal to 10%, the color difference ΔE between the first surface color and the second surface color is ＊ ab It is 0 or more, preferably 0.5 or more, and more preferably 1.0 or more.

[0064] As the color value of the backing paper when aging discoloration occurs, L ＊ Therefore, when comparing the inner color of the first surface with the inner color of the second surface, the L value of the inner color of the first surface is usually ＊ The value is less than the L of the inner color of the second surface ＊ value.

[0065] In this case, the protruding margin area of ​​the glass plate backing paper located closest to the first direction is set at L ＊ a ＊ b ＊ The color value in the color system is set as the first prominent residual color, and the color difference ΔE between the first prominent residual color and the second surface internal color ＊ ab It is preferably equal to or less than a predetermined value.

[0066] The protruding margin area of ​​the glass plate backing paper is also the part of the glass plate laminate where the glass plate backing paper is exposed, and is the part that is more susceptible to aging discoloration. Although the protruding margin area does not directly contact the main surface of the glass plate, when aging discoloration occurs in the protruding margin area, particles adhere to the end surface of the glass plate, resulting in the possibility of reducing the quality of the glass plate. In view of this, by making the color difference ΔE between the first protruding margin color and the second surface color ＊ ab If the color of the protruding margin area is less than the specified value, it can be said that the aging discoloration of the protruding margin area is suppressed, and the adhesion of particles to the end surface of the glass plate can also be suppressed. It should be noted that the protruding margin color of the glass plate backing paper is measured at least 10% inside the end of the protruding margin area that contacts the glass plate and the cut edge of the backing paper.

[0067] When the ash content of the glass plate interleaving paper is 0.001% to 0.5%, the color difference ΔE between the first protruding residual color and the second surface internal color ＊ ab It is preferably 0.58 or less, more preferably 0.57 or less, and further preferably 0.56 or less.

[0068] In addition, when the ash content of the glass plate interleaving paper is greater than 0.5% and less than or equal to 10%, the color difference ΔE between the first protruding residual color and the second surface internal color is ＊ ab It is preferably 5.0 or less, more preferably 4.5 or less, and further preferably 4.0 or less.

[0069] From the same viewpoint as the lower limit of the color difference between the first surface inner color and the second surface inner color, when the ash content of the glass plate interleaving paper is 0.001% to 0.5%, the color difference ΔE between the first protruding residual color and the second surface inner color is ＊ ab is 0 or more, preferably 0.2 or more, and more preferably 0.3 or more. In addition, when the ash content of the glass plate interleaving paper is greater than 0.5% and less than or equal to 10%, the color difference ΔE between the first protruding residual color and the second surface color is ＊ ab It is 0 or more, preferably 0.5 or more, and more preferably 1.0 or more.

[0070] The absolute color value of the glass plate interleaving paper depends on the type of glass plate interleaving paper used, and therefore is not particularly limited. As an example, in the case of a glass plate interleaving paper containing virgin pulp and not intentionally colored, L ＊ a ＊ b ＊ The color value in the color system is preferably L ＊ : 90 and above, a ＊ :-0.4 or more, b＊ : 6.0 or less, more preferably L ＊ : 95 or more and 99.5 or less, a ＊ : greater than -1.0 and less than or equal to -0.4, b ＊ : Greater than or equal to 1.0 and less than 6.0.

[0071] In the case of a glass plate interleaving paper containing recycled pulp and not intentionally colored, L ＊ a ＊ b ＊ The color value in the color system is preferably L ＊ : greater than or equal to 70 and less than 90, a ＊ :-0.3 or more and 1.0 or less, b ＊ : 9.0 or less, more preferably L ＊ : 75 or more and 85 or less, a ＊ :-0.3 or more and 0.5 or less, b ＊ : 2.0 or more and 9.0 or less.

[0072] In addition, not intentionally colored means, for example, that the glass plate interleaving paper does not contain a colorant such as a paint, a pigment, or a dye, or even if it contains contaminants, the content thereof is 0.5 mass % or less.

[0073] Figure 1 The glass plate laminate 10 shown is a structure in which N sheets (N is an integer greater than or equal to 2) of glass plate backing paper 1 and glass plates 2 are alternately stacked. The number of stacked sheets of glass plate backing paper 1 and glass plates 2 is not limited thereto, and can be appropriately changed according to various conditions such as the strength and size of the glass plate 2 and the size of the packaging container. The number of stacked glass plates (N) can be more than 2, and the upper limit is, for example, less than 800 sheets. The number of stacked sheets is more preferably 150 to 600 sheets. The glass plate laminate 10 is usually stacked in such a way that the total mass is less than 2000 kg.

[0074] The number of sheets of the glass plate 2 and the glass plate interleaving paper 1 stacked is usually the same as that of the glass plate interleaving paper 1 or one more than that of the glass plate 2 .

[0075] (Method for producing glass sheet laminate)

[0076] The glass plate laminate of the present embodiment can be manufactured by laminating glass plates and glass plate backing paper by a known method. In this case, for example, by covering the carrier with a material with low light transmittance or a thick film or sheet immediately after the carrier is formed, or by adding a light-absorbing material to the glass plate backing paper, the aging discoloration of the upper surface side of the glass plate laminate can be suppressed, thereby obtaining the glass plate laminate of the present embodiment.

[0077] (glass plate)

[0078] The type of glass plate constituting the glass plate laminate is not particularly limited, and known glass plates can be used. For example, the glass plate is preferably a glass plate used in connection with the manufacture of liquid crystal products and semiconductor products, and the surface of which is required to be kept highly clean, such as a glass substrate for a liquid crystal display, a glass substrate for an organic EL, and other flat panel displays; a glass plate for protective glass; a glass plate for semiconductor packaging; and a glass plate used in electronic devices such as solar cells.

[0079] The material of the glass plate is not particularly limited and can be appropriately selected according to the application, for example, soda-lime glass, aluminosilicate glass, borosilicate glass, alkali-free aluminosilicate glass, quartz glass, etc. In addition, a glass plate containing ultraviolet and infrared absorbing glass or tempered glass can also be used.

[0080] The shape, size, thickness, etc. of the glass plate are not particularly limited, and may be any shape, size, thickness, etc. that allows two or more sheets to be stacked, stored, and transported.

[0081] The shape of the glass plate may be, for example, Figure 1 The glass plate shown may be a flat plate, or may be a curved surface having curvature in the entire surface or in part.

[0082] The thickness of the glass plate can be appropriately adjusted according to the application, and is, for example, 0.01 mm to 10 mm.

[0083] The size of the glass plate may be, for example, the size of the 8th generation (2200 mm×2500 mm) developed in recent years. In this case, from the viewpoint of ensuring strength, the thickness of the glass plate is preferably 0.2 mm to 0.8 mm, more preferably about 0.3 mm to 0.7 mm.

[0084] The glass plate may be a laminated glass in which a plurality of glass plates are bonded together with an interlayer film interposed therebetween.

[0085] The manufacturing method of the glass plate is not particularly limited. For example, it can be formed into a specified plate thickness by pressing, down-drawing, float glass, etc., and then slowly cooled, and then ground, polished, etc. to make a glass plate of specified size and shape.

[0086] In addition, the glass plate may have a functional thin film on the surface. Specifically, the functional thin film refers to a conductive film (having tin-doped indium oxide (ITO), zinc oxide (ZnO), tin oxide (SnO 2), Ag, Cr / Cu / Cr structured films, etc.), heat ray shielding films (layers having a structure of oxide (e.g., zinc oxide, titanium oxide, ITO, etc.) / Ag / oxide, etc.). Here, zinc oxide may be doped with Al, Ga, or hydrogen, etc. In addition, tin oxide may be doped with F or Sb. In addition, Ag may be doped with Pd or Au.

[0087] (Paper for glass plate)

[0088] The type of glass plate backing paper constituting the glass plate laminate is not particularly limited, and known backing paper can be used. For example, it can be appropriately selected from the glass plate backing paper containing virgin pulp, glass plate backing paper containing waste paper pulp, glass plate backing paper containing mixed pulp of virgin pulp and waste paper pulp, etc., according to the desired characteristics, etc. It should be noted that the glass plate backing paper containing specific pulp means that the proportion of the specific pulp in the pulp used as the raw material of the glass plate backing paper is substantially 100% by mass, and no other type of pulp is intentionally mixed.

[0089] In this specification, virgin pulp refers to pulp produced from wood or the like, and does not refer to pulp made from paper made from paper or waste paper.

[0090] The specific type of pulp in the virgin pulp is not particularly limited, and can be appropriately selected according to the characteristics required as the backing paper for the glass plate. As the virgin pulp, one type of pulp can be used alone, or multiple types of pulps can be used in combination. As the types of pulp, for example, chemical pulps such as kraft pulp (KP), sulfite pulp (SP), and alkaline pulp (AP); mechanical pulps such as groundwood pulp (GP), thermomechanical pulp (TMP), and chemical thermomechanical pulp (CTMP); and semi-chemical pulps such as chemical groundwood pulp (CGP) and semi-chemical pulp (SCP) as intermediate mechanical / chemical pulps. The pulp can be bleached or unbleached, for example, hardwood bleached kraft pulp (LBKP), coniferous bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), and coniferous unbleached kraft pulp (NUKP) in KP can be used.

[0091] Since high cleanliness is required for the interleaving paper for glass plates, bleached kraft pulp (LBKP and NBKP) that has been subjected to a bleaching treatment and in which components such as resin components derived from lignin and the like are washed to reduce their amounts is particularly preferred as the raw material pulp.

[0092] (Waste paper pulp)

[0093] In this specification, waste paper pulp refers to pulp recovered from waste paper. Waste paper pulp is pulp derived from waste paper such as newspapers, magazines, and flyers, and is sometimes referred to as deinked pulp (DIP). Deinked pulp refers to pulp obtained by subjecting waste paper as a raw material to dust removal / deinking treatment and separation of ink. Waste paper pulp may also be pulp derived from waste paper used as a glass plate liner.

[0094] The basis weight of the interleaving paper for glass plates is preferably 30 g / m 2 ~100g / m 2 When the basis weight of the glass plate interleaving paper of the present embodiment is small, it may be easy to break due to reduced strength. Therefore, the basis weight of the glass plate interleaving paper of the present embodiment is preferably 30 g / m 2 More preferably 35g / m 2 More preferably, 40 g / m 2 Above, particularly preferably 45g / m 2 above.

[0095] On the other hand, when the basis weight of the glass plate interleaving paper is large, the weight increases, and the stacking height when the glass plate interleaving paper and the glass plate are stacked to obtain a stacked body becomes high, so the number of sheets that can be accommodated in a container of a predetermined height decreases. Therefore, the basis weight of the glass plate interleaving paper of this embodiment is preferably 100 g / m 2 Below, more preferably 90g / m 2 Below, more preferably 80g / m 2 Below, particularly preferably 70g / m 2 the following.

[0096] The basis weight can be measured according to JIS P 8124:2011.

[0097] Moreover, from the same viewpoint as above, it is preferable that the thickness of the interleaving paper for glass plates of this embodiment is 30 micrometers - 150 micrometers.

[0098] The glass plate to be laminated together with the glass plate backing paper of the present embodiment is usually rectangular, so the glass plate backing paper of the present embodiment is also preferably rectangular. In addition, in order to be used for laminating large glass plates, the glass plate backing paper of the present embodiment preferably has a length of at least one side of the rectangle of 500 mm or more, more preferably 1000 mm or more, further preferably 1500 mm or more, and particularly preferably 2200 mm or more. The upper limit is not particularly limited, but is, for example, 4000 mm or less.

[0099] For example, when the glass plate is rectangular and has a size of 2200 mm × 2500 mm, the glass plate backing paper is preferably a rectangle of about 2280 mm × about 2580 mm. When the glass plate is rectangular, the length of each side of the glass plate backing paper is preferably about 1.02 to 1.05 times the length of the side of the corresponding glass plate.

[0100] The glass plate backing paper of the present embodiment can have various chemicals added internally or externally (coated, impregnated, etc.) within the range in which the effects of the present invention are exerted. Examples of the chemicals added internally or externally to the glass plate backing paper include aluminum sulfate, defoaming agents, fixing agents, paper strength enhancers, yield improvers, coagulants, surfactants, sizing agents, antistatic agents, slime control agents, dryer stripping agents, polyvinyl alcohol, polyacrylamide, starch, cellulose derivatives such as CMC, fillers (talc, clay, titanium dioxide, calcium carbonate, etc.), etc.

[0101] The glass plate backing paper of the present embodiment can be manufactured by a known method. For example, the glass plate backing paper can be obtained by a method including the following steps: a preparation step of preparing pulp as a raw material; a preparation step of manufacturing pulp slurry from the pulp; and a papermaking step of making paper from the pulp slurry to obtain the glass plate backing paper.

[0102] (Glass plate packaging)

[0103] The glass plate package of the present embodiment includes: the glass plate laminated body of the present embodiment; and a storage container that stores the glass plate laminated body.

[0104] When transporting and storing glass plates, glass plates and glass plates are alternately stacked with lining paper to obtain a stacked body, which is then stored in a storage container and packaged to obtain a package (glass plate package). Examples of the storage container include a storage box and a pallet. Examples of the storage box include a storage box including a box body and a cover body for storing the glass plate stacked body. In addition, the glass plate package using a pallet includes a horizontal type in which glass plates are stacked horizontally and a vertical type in which glass plates are stacked in a state where the glass plates are tilted and erected, and the present embodiment can be applied to either type. Figure 6 The following is a schematic diagram of an example of a glass plate package using a vertically placed pallet. Figure 7 A schematic configuration of an example of a glass plate package using a horizontally placed pallet is shown.

[0105] In the glass plate package of the present embodiment, the L of the first surface inner color of the glass plate laminate is ＊ The value is less than the L of the inner color of the second surface ＊The glass plate stack is placed in a manner such that the surface of the glass plate stack on the second direction side faces the placement plate of the storage container. In the state of the glass plate package, the surface that is usually arranged to face the placement surface of the storage container when the glass plate stack is stored in the storage container is the lower surface side of the glass plate stack that is less likely to undergo aging discoloration.

[0106] Figure 6 The glass plate package 30 shown is a package obtained by placing a glass plate laminate 10 on a pallet 31 and packaging it. The glass plate laminate 10 is obtained by stacking a plurality of glass plates 2 in a manner of sandwiching a glass plate backing paper 1 therebetween. It should be noted that the glass plate backing paper 1 is preferably also arranged between the pallet 31 and the glass plate 2. The pallet 31 is a pallet for glass plate packaging of a well-known vertical type, which has: a base 33, a back plate 32 erected on the upper surface of the base 33, and a bottom plate 34 placed on the upper surface of the base 33. It should be noted that the back plate 32 is sometimes called a tilting table or a loading plate. In addition, the bottom plate 34 is sometimes called a loading table. In this example, the stacking direction of the glass plate laminate is a direction perpendicular to the loading surface of the back plate 32 of the pallet 31.

[0107] One side of the back plate 32 in the vertical direction (the contact surface with the glass plate laminate 10, hereinafter also referred to as "inclined surface") is inclined relative to the vertical direction. The angle of the inclined surface ( Figure 3 ) may be an angle at which the stacked glass plate stack 10 can be stably loaded, stored and transported, and is usually 85° or less, for example, 85° to 70°, relative to the horizontal direction.

[0108] The upper surface of the bottom plate 34 is inclined relative to the horizontal direction so as to descend toward the back plate 32. In the illustrated example, the upper surface of the bottom plate 34 is configured to be 90 degrees relative to the inclined surface of the back plate 32 as an example.

[0109] In the pallet 31, the glass plates 2 are stacked in a state of being placed on the upper surface of the bottom plate 34 and leaning against the inclined surface of the back plate 32. In addition, the glass plate backing paper 1 is sandwiched between the glass plates. In addition, the surface of the front glass plate can be covered with the glass plate backing paper. In the case of using a vertically placed glass plate packaging pallet, the glass plate stack is placed with its second direction side surface facing the inclined surface of the back plate 32 of the pallet.

[0110] Figure 7The glass plate package 50 shown is a package obtained by placing a glass plate laminate 10 on a pallet 51 and packaging it. The glass plate laminate 10 is obtained by stacking a plurality of glass plates 2 in a manner of sandwiching a glass plate backing paper 1 therebetween. It should be noted that the glass plate backing paper 1 is preferably also arranged between the pallet 51 and the glass plate 2. The pallet 51 is a pallet for horizontally placed glass plate packaging as is known in the art, and has a base 53 and a back plate 52 placed on the upper surface of the base 53. In addition, pillars 52 for stacking the pallet 51 are provided at the corners of the upper surface of the base 53 (for example, at least four corners if the upper surface of the base 53 is rectangular). When a pallet for horizontally placed glass plate packaging is used, the glass plate laminate is placed with its surface on the second direction side facing the back plate 52 of the pallet. It should be noted that the back plate 52 is sometimes referred to as a loading plate. In this example, the stacking direction of the glass plate stack is a direction perpendicular to the placement surface of the back plate 52 of the pallet 51 .

[0111] As described above, the present specification discloses the following matters.

[0112] (1) A glass plate stack, the glass plate stack being to be stored in a storage container, wherein the glass plate stack has a structure in which a plurality of glass plates and a plurality of glass plate backing papers are alternately stacked, the glass plate backing papers being backing papers containing virgin pulp, wherein a direction away from the storage container in the stacking direction of the glass plate stack is set as a first direction, a direction opposite to the first direction is set as a second direction, a principal surface of the glass plate backing paper on the first direction side is set as a first principal surface, an area of ​​the first principal surface of the glass plate backing paper that contacts or corresponds to a principal surface of an adjacent glass plate is set as an in-plane area, and the in-plane area of ​​the glass plate backing paper that is closest to the first direction side of the glass plate stack in the glass plate stack is set as L ＊ a ＊ b ＊ The color value in the colorimetric system is set as the first in-plane color, and the in-plane region of the glass plate interleaving paper which is located closest to the second direction side of the glass plate laminated body in the glass plate laminated body is set at L ＊ a ＊ b ＊ The color value in the color system is set as the second surface color. At this time, the color difference ΔE between the first surface color and the second surface color is ＊ ab Below 0.58.

[0113] (2) The glass plate laminate according to (1), wherein an area of ​​the first main surface of the glass plate backing paper other than the in-plane area is set as a protruding margin area, and the protruding margin area of ​​the glass plate backing paper located closest to the first direction side of the glass plate laminate is set at L ＊ a ＊ b ＊ The color value in the color system is set to the first prominent residual color. At this time, the color difference ΔE between the first prominent residual color and the second surface color is ＊ ab Below 0.58.

[0114] (3) The glass plate laminate according to (1), wherein L of the glass plate interleaving paper is ＊ The content of carbon is 90% or more, and the content of ash is 0.001% or more and 0.5% or less.

[0115] (4) The glass plate laminate according to (2), wherein L of the glass plate interleaving paper is ＊ The content of carbon is 90% or more, and the content of ash is 0.001% or more and 0.5% or less.

[0116] (5) A glass plate stack, the glass plate stack being to be stored in a storage container, wherein the glass plate stack has a structure in which a plurality of glass plates and a plurality of glass plate backing papers are alternately stacked, the glass plate backing papers are backing papers containing waste paper pulp, a direction away from the storage container in the stacking direction of the glass plate stack is set as a first direction, a direction opposite to the first direction is set as a second direction, a principal surface of the glass plate backing paper on the first direction side is set as a first principal surface, an area of ​​the glass plate backing paper that contacts or corresponds to a principal surface of an adjacent glass plate is set as an in-plane area, and the in-plane area of ​​the glass plate backing paper that is closest to the first direction side of the glass plate stack in the glass plate stack is set at L ＊ a ＊ b ＊ The color value in the colorimetric system is set as the first in-plane color, and the in-plane region of the glass plate interleaving paper which is located closest to the second direction side of the glass plate laminated body in the glass plate laminated body is set at L ＊ a ＊ b ＊ The color value in the color system is set as the color in the second plane. At this time, the color difference ΔE between the color in the first plane and the color in the second plane is ＊ ab Below 5.0.

[0117] (6) The glass plate laminate according to (4), wherein an area of ​​the first main surface of the glass plate backing paper other than the in-plane area is set as a protruding margin area, and the protruding margin area of ​​the glass plate backing paper located closest to the first direction side of the glass plate laminate is set at L ＊ a ＊ b ＊ The color value in the color system is set to the first prominent residual color. At this time, the color difference ΔE between the first prominent residual color and the second surface internal color is ＊ ab Below 5.0.

[0118] (7) The glass plate laminate according to (5), wherein L of the glass plate interleaving paper is ＊ Greater than or equal to 70% and less than 90%, ash content greater than 0.5% and less than or equal to 10%.

[0119] (8) The glass plate laminate according to (6), wherein L of the glass plate interleaving paper is ＊ Greater than or equal to 70% and less than 90%, ash content greater than 0.5% and less than or equal to 10%.

[0120] (9) The glass plate laminate according to any one of (1) to (8), wherein a glass plate interleaving paper is laminated on each of the outermost surface on the first direction side and the outermost surface on the second direction side of the glass plate laminate.

[0121] (10) The glass plate laminate according to any one of (1) to (8), wherein a glass plate is laminated on the outermost surface on the first direction side of the glass plate laminate, and a glass plate backing paper is laminated on the outermost surface on the second direction side of the glass plate laminate.

[0122] (11) A glass plate package comprising: the glass plate stack according to any one of 1 to 10; and a storage container for storing the glass plate stack, wherein the glass plate stack is placed with the surface of the glass plate stack on the second direction side facing the storage container.

[0123] Example

[0124] Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.

[0125] (Test Example 1: Sunlight exposure test of interleaving paper for glass plate)

[0126] As a glass plate interleaving paper, a glass plate interleaving paper A (L) containing virgin pulp (bleached coniferous kraft pulp) was prepared. ＊ =97.5, a ＊=-0.6, b ＊ =5.1, ash content 0.20%), and glass plate interleaving paper B (L ＊ =83.1, a ＊ =0.5, b ＊ =5.7, ash content 3.5%).

[0127] In a polyethylene transparent bag treated with an ionizer (static eliminator), a sheet of glass plate interleaving paper was placed without rubbing as a sample for sunlight exposure test. A plurality of samples of each of glass plate interleaving paper A and glass plate interleaving paper B were prepared.

[0128] The prepared samples were kept in a test room for a predetermined period of time in a state where they were attached to a south-facing window where sunlight was incident from the inside of the room, thereby conducting a sunlight exposure test. In addition, some samples were not exposed to sunlight but were placed in a black box for dark storage.

[0129] (Determination of color value)

[0130] The L values ​​of sample 1 stored in a dark place for 2 months and samples 2 to 4 stored for 0.5 month, 1 month, and 2 months respectively and exposed to sunlight were measured by the following method. ＊ a ＊ b ＊ Color value in the colorimetric system. It should be noted that, when measuring color, 30 or more sheets of glass plate backing paper with a size of 50 mm × 50 mm or more processed under the same conditions are stacked, and the top glass plate backing paper is changed to a different backing paper each time, and at least 5 measurements are performed under each condition, and the average value is used as the color measurement result. When the number of stacked glass plate backing papers is small, the light of the colorimeter is easy to pass through the glass plate backing paper, so the light incident on the light receiving part of the colorimeter is greatly affected by the object located on the back of the glass plate backing paper, so the color may not be accurately measured. The more sheets of glass plate backing paper are stacked, the closer it is to a fixed value. When more than 30 sheets are stacked, the color measurement result becomes a roughly fixed value regardless of the number of sheets, so a more accurate color measurement result is obtained. The results of color difference obtained by measuring color values ​​are shown in Table 1. It should be noted that the color difference values ​​of samples 2 to 4 are values ​​based on the color value of sample 1 (stored in a dark place for 2 months).

[0131] (Color measurement conditions) Device: Spectrophotometer CM-700d manufactured by Konica Minolta Inc. Illumination / light receiving optical system: SCI method (including regular reflection light) Measurement diameter: SAV (diameter 6 mm) Observation light source: D65 light source Observation conditions: 10° field of view Color system: L ＊ a ＊ b＊ Color system

[0132]

[0133] (Test Example 2: Loading Test)

[0134] Glass plate laminates 1 to 4 were prepared using samples produced under the same conditions as those of glass plate interleaving papers of Samples 1 to 4 in Test Example 1, and the number of particles on the surface of the glass plates after storage under predetermined conditions was measured.

[0135] The glass plate liner (520 mm long × 420 mm wide) of each sample and the glass plate (470 mm long × 370 mm wide × 0.5 mm thick, alkali-free glass substrate manufactured by AGC Corporation: AN100) were alternately stacked to obtain a glass plate laminate containing more than 30 glass plates. A load equivalent to 2 kPa was loaded on the obtained glass plate laminate, and it was stored for 16 hours at a temperature of 80°C and a relative humidity of 40%. It should be noted that the temperature increase from room temperature to 80°C and the temperature decrease from 80°C to room temperature each took 4 hours.

[0136] <Measurement of the number of particles on the glass plate surface>

[0137] The glass plates taken out from the glass plate stacks 1 to 4 that have undergone the loading test are passed through a cleaning machine with the wiring forming surface facing upward. The cleaning machine includes two rows of spray pipes in the upper and lower rows, the pipe pressure of the spray pipes is 1 MPa, pure water (ion exchange water) flows at a flow rate of 20 L / min, the discharge outlets are nozzles of uniform fan shape, and the discharge is discharged from a shower head with 5 nozzles in each tube. The glass plate is passed through the cleaning machine at a speed of 3 m / min and dried with an air knife that sprays clean dry air, thereby obtaining a cleaned substrate. The cleaned substrate is measured in Normal (1.0 μm) mode using a foreign matter inspection machine for FPD (manufactured by Toray Engineering Co., Ltd., HS-830e), thereby obtaining the number of particles. It should be noted that the particles of the foreign matter inspection machine usually include not only convex attachments but also concave scratches, but in this specification, convex attachments are referred to as particles and concave defects are referred to as scratches.

[0138] In addition, the sizes of the particles confirmed were classified and evaluated as follows. The results are shown in Figure 8 , Fig. 9 It should be noted that Figure 8 , Fig. 9 The bar graph is a graph of average values ​​obtained by measuring samples under the same conditions three or more times, and the maximum value and the minimum value are shown together.

[0139] L (Large): The diameter of the standard particle is 5 μm or more. M (Medium): The diameter of the standard particle is 3 μm or more and less than 5 μm. S (Small): The diameter of the standard particle is 1 μm or more and less than 3 μm.

[0140] The results in Table 1 show that the longer the glass plate is exposed to light, the more the color value changes. The color difference ΔE compared to the state of storage in the dark is ＊ ab The larger it gets, the greater the degree of aging and discoloration. Figure 8 , Fig. 9 The results show that the greater the degree of aging discoloration of the glass plate backing paper, the more particles are detected. This shows that when glass plates and glass plate backing papers are alternately stacked to form a glass plate laminate, if the color difference ΔE between the first surface color and the second surface color is ＊ ab When the content is equal to or less than a predetermined value, particles on the surface of the glass plate can be suppressed.

[0141] This application is based on Japanese patent application 2023-094386 filed on June 7, 2023, the contents of which are incorporated herein by reference.

Claims

1. A glass plate laminate, the glass plate laminate being a glass plate laminate to be stored in a storage container, in, The glass plate laminate has a structure in which a plurality of glass plates and a plurality of glass plate backing papers are alternately stacked. The glass plate backing paper is a backing paper containing virgin pulp, A direction away from the storage container in a stacking direction of the glass plate stack is defined as a first direction, and a direction opposite to the first direction is defined as a second direction, The main surface of the glass plate interleaving paper on the first direction side is defined as a first main surface, The area of ​​the first main surface of the interleaving paper for glass plates that contacts or corresponds to the main surface of the adjacent glass plate is defined as an in-plane area. The in-plane region of the glass plate interleaving paper which is located closest to the first direction side of the glass plate laminate is L ＊ a ＊ b ＊ The color value in the colorimetric system is set as the first in-plane color, and the in-plane region of the glass plate interleaving paper which is located closest to the second direction side of the glass plate laminated body in the glass plate laminated body is set at L ＊ a ＊ b ＊ The color value in the color system is set to the color in the second plane. At this time, the color difference ΔE between the first surface color and the second surface color ＊ ab Below 0.

58.

2. The glass sheet laminate according to claim 1, in, The area of ​​the first main surface of the interleaving paper for glass plates other than the in-plane area is set as a protruding margin area. The protruding margin area of ​​the glass plate interleaving paper located closest to the glass plate laminate in the first direction is L ＊ a ＊ b ＊ The color value in the color system is set to the first prominent residual color. At this time, the color difference ΔE between the first protruding residual color and the second surface color is ＊ ab Below 0.

58.

3. The glass sheet laminate according to claim 1, in, The L of the glass plate backing paper ＊ The content of carbon is 90% or more, and the content of ash is 0.001% or more and 0.5% or less.

4. The glass sheet laminate according to claim 2, in, The L of the glass plate backing paper ＊ The content of carbon is 90% or more, and the content of ash is 0.001% or more and 0.5% or less.

5. The glass sheet laminate according to claim 1, in, The interleaving paper for a glass plate is rectangular, and the length of at least one side of the rectangle is 500 mm or more and 4000 mm or less.

6. A glass plate laminate, the glass plate laminate being a glass plate laminate to be stored in a storage container, in, The glass plate laminate has a structure in which a plurality of glass plates and a plurality of glass plate backing papers are alternately stacked. The glass plate backing paper is a backing paper containing waste paper pulp, A direction away from the storage container in a stacking direction of the glass plate stack is defined as a first direction, and a direction opposite to the first direction is defined as a second direction, The main surface of the glass plate interleaving paper on the first direction side is defined as a first main surface, The area of ​​the first main surface of the interleaving paper for glass plates that contacts or corresponds to the main surface of the adjacent glass plate is defined as an in-plane area. The in-plane region of the glass plate interleaving paper which is located closest to the first direction side of the glass plate laminate is L ＊ a ＊ b ＊ The color value in the colorimetric system is set as the first in-plane color, and the in-plane region of the glass plate interleaving paper which is located closest to the second direction side of the glass plate laminated body in the glass plate laminated body is set at L ＊ a ＊ b ＊ The color value in the color system is set to the color in the second plane. At this time, the color difference between the first surface color and the second surface color is ΔE ＊ ab Below 5.

0.

7. The glass sheet laminate according to claim 6, in, The area of ​​the first main surface of the interleaving paper for glass plates other than the in-plane area is set as a protruding margin area. The protruding margin area of ​​the glass plate interleaving paper located closest to the glass plate laminate in the first direction is L ＊ a ＊ b ＊ The color value in the color system is set to the first prominent residual color. At this time, the color difference ΔE between the first protruding residual color and the second surface color is ＊ ab Below 5.

0.

8. The glass sheet laminate according to claim 6, in, The L of the glass plate backing paper ＊ Greater than or equal to 70% and less than 90%, ash content greater than 0.5% and less than or equal to 10%.

9. The glass sheet laminate according to claim 7, in, The L of the glass plate backing paper ＊ Greater than or equal to 70% and less than 90%, ash content greater than 0.5% and less than or equal to 10%.

10. The glass sheet laminate according to claim 6, in, The interleaving paper for a glass plate is rectangular, and the length of at least one side of the rectangle is 500 mm or more and 4000 mm or less.

11. The glass sheet laminate according to any one of claims 1 to 10, in, Interleaving papers for glass plates are laminated on the outermost surface on the first direction side and the outermost surface on the second direction side of the glass plate laminate.

12. The glass sheet laminate according to any one of claims 1 to 10, in, A glass plate is laminated on the outermost surface of the glass plate laminate on the first direction side, and a glass plate interleaving paper is laminated on the outermost surface of the glass plate laminate on the second direction side.

13. A glass plate packaging body, in, The glass plate package comprises: the glass plate laminate according to any one of claims 1 to 10; and a storage container for storing the glass plate laminate. The glass plate laminate is placed such that the surface of the glass plate laminate on the second direction side faces the storage container.

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