Laminating paper for glass plates, glass plate laminates, and glass plate packaging.

Abstract

To provide laminated paper for a glass plate containing waste paper, capable of suppressing scratches and contamination of the glass plate, suppressing defects in unpacking of a glass plate laminate, and having good handling properties in use.SOLUTION: The present invention relates to laminated paper for a glass plate containing virgin pulp and recycled pulp, wherein the recycled pulp is recycled pulp derived from waste paper of the laminated paper for the glass plate, 10 mass% or more and 90 mass% or less of the recycled pulp is contained, and a content of deinked pulp (DIP) is 0.1 mass% or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to laminates for glass plates, glass plate laminates, and glass plate packaging. [Background technology]

[0002] Glass plates that incorporate electrical circuits and other components on their surface, such as alkali-free glass plates used in liquid crystal displays, can experience disconnections or patterning defects even with slight scratches or contamination on their surface. Therefore, such glass plates require extremely high surface properties. To prevent scratches and contamination during storage and transportation of glass plates, a conventional method has been employed in which glass plate interleaving paper (hereinafter simply referred to as "interleaving paper") is inserted between stacked glass plates to separate the surfaces of adjacent glass plates.

[0003] A configuration in which glass plates are interposed with interleaving paper for glass plates is called a glass plate laminate. The glass plate laminate is stored in a pallet equipped with, for example, an interleaving paper retaining member (lateral retaining member) that presses down on the interleaving paper that protrudes from the sides of the glass plate laminate. The configuration in which the glass plate laminate is stored in a pallet is called a glass plate package.

[0004] When removing glass plates from a glass plate packaging, the interleaving paper that protrudes from the sides of the glass plate laminate is generally pressed against the sides of the glass plate laminate to prevent the interleaving paper from being removed along with the glass plates. In order to press the interleaving paper against the sides of the glass plate laminate, the edges of the interleaving paper for glass plates are usually folded in advance downwards (on the opposite side from the direction in which the glass plates are removed) from the plane formed by the main surface of the glass plate that is in contact with the interleaving paper.

[0005] While virgin pulp is generally used as the raw material for laminating paper for glass plates, recycled paper pulp is sometimes used from the perspective of environmental considerations and cost reduction. For example, Patent Document 1 states that the raw material pulp used for laminating paper for glass plates may be recycled paper pulp, virgin pulp, or a mixture of recycled paper pulp and virgin pulp. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2021-63317 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, when recycled paper pulp is used as a raw material, depending on the type of recycled paper pulp, problems may arise such as contamination of the glass plates when used as laminating paper for glass plates. Also, if the laminating paper is too stiff, it tends to return to its original state over time after being folded (rebounding), which can cause problems such as the laminating paper not being able to be pressed against the side of the glass plate laminate when removing the glass plates from the glass plate packaging, resulting in the laminating paper being removed along with the glass plates. Furthermore, if the laminating paper is too weak, problems may arise such as poor handling during use.

[0008] In view of the above, the present invention aims to provide a glass plate interlining containing recycled paper pulp as a raw material, which can suppress scratches and contamination of glass plates while containing recycled paper, can suppress problems when unpacking the glass plate laminate, and has excellent handling properties during use. The present invention also aims to provide a glass plate laminate having the above glass plate interlining between a plurality of glass plates, and a glass plate packaging having the above glass plate laminate. [Means for solving the problem]

[0009] The inventors of the present invention have discovered that the above problems can be solved by using glass plate lamination paper that contains recycled pulp derived from waste paper used for glass plate lamination paper as a raw material pulp, and in which the content of recycled pulp is adjusted to a specific range, and have completed the present invention.

[0010] In other words, the present invention relates to items 1 to 8 below. 1. A base paper for a glass plate, comprising virgin pulp and recycled pulp, wherein the recycled pulp is recycled pulp derived from waste base paper for a glass plate, the recycled pulp is contained at 10% by mass or more and 90% by mass or less, and a base paper for a glass plate having a content of deinked pulp (DIP) of 0.1% by mass or less. 2. The base paper for a glass plate according to 1 above, wherein the Clark stiffness with respect to the paper-making direction of the base paper for a glass plate is less than 40 cm 3 / 100. 3. In the fiber width distribution of the disintegrated pulp obtained by disintegrating the base paper for a glass plate, when the median value of the fiber width is Me, the ratio of fibers having a fiber width of (Me - 0.5Me) or more and (Me + 0.5Me) or less is 70% or more, the base paper for a glass plate according to 1 or 2 above. 4. The length-weighted average fiber length distribution of the disintegrated pulp obtained by disintegrating the base paper for a glass plate is classified into the following classes (A) to (F), and when the ratios (%) of the fibers belonging to each of the classes are represented as (a) to (f), any one or more of (b)+(c), (c)+(d) and (d)+(e) is 50% or more, the base paper for a glass plate according to 1 or 2 above. (A) More than 0 mm and less than 0.2 mm (B) 0.2 mm or more and less than 0.6 mm (C) 0.6 mm or more and less than 1.2 mm (D) 1.2 mm or more and less than 2.0 mm (E) 2.0 mm or more and less than 3.2 mm (F) 3.2 mm or more and 7.6 mm or less 5. The base paper for a glass plate according to 1 or 2 above, wherein the aspect ratio obtained by dividing the Clark stiffness with respect to the paper-making direction of the base paper for a glass plate by the Clark stiffness with respect to the direction orthogonal to the paper-making direction is 1.80 or more and 2.40 or less. 6. The base paper for a glass plate according to 1 or 2 above, wherein the concentrations of each of the elements magnesium, silicon, titanium, iron and chromium measured by fluorescent X-ray analysis all satisfy the following conditions (1) to (5). (1) Magnesium 200 ppm or less (2) Silicon 300 ppm or less (3) Titanium 0.10 ppm or less (4) Iron: 0.50 ppm or less (5) Chromium 1.0 ppm or less 7. A glass plate laminate in which multiple glass plates are stacked together, A glass plate laminate having the glass plate interleaving paper described in 1 or 2 between the glass plates. 8. A glass plate packaging body comprising the glass plate laminate described in item 7 above and a pallet on which the glass plate laminate is placed. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide glass plate interleaving paper that can suppress scratches and contamination of glass plates while containing recycled paper, suppress problems when unpacking glass plate laminates, and have good handling properties during use, a glass plate laminate having said glass plate interleaving paper, and a glass plate packaging having said glass plate laminate. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a cross-sectional view showing a schematic configuration of an example of a glass plate laminate using glass plate lamination according to an embodiment of the present invention. [Figure 2] Figure 2 is a side view showing a schematic configuration of an example of a glass plate packaging. [Figure 3] Figure 3 is a side view showing a schematic configuration of another example of a glass plate packaging. [Modes for carrying out the invention]

[0013] The present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be modified and implemented as appropriate without departing from the spirit of the invention. Furthermore, the "~" indicating a numerical range is used to mean that the numbers written before and after it are included as the lower limit and upper limit. Furthermore, in the following drawings, components and parts that perform the same function may be denoted by the same reference numeral and described accordingly, and redundant explanations may be omitted or simplified. Also, the embodiments shown in the drawings are schematic representations for the purpose of clearly illustrating the present invention and do not necessarily accurately represent the actual size or scale.

[0014] (Laminating paper for glass plates) The glass plate lamination according to this embodiment is a glass plate lamination comprising virgin pulp and recycled pulp, wherein the recycled pulp is recycled pulp derived from recycled glass plate lamination paper, and the glass plate lamination contains 10% by mass or more and 90% by mass or less of the recycled pulp, and has a deinking pulp (DIP) content of 0.1% by mass or less.

[0015] The glass plate interleaving paper is used by being interposed between glass plates. Figure 1 shows an example of a glass plate laminate having the glass plate interleaving paper according to this embodiment. In the glass plate laminate 10 illustrated in Figure 1, the glass plate interleaving paper 1 is interposed between a plurality of glass plates 2.

[0016] As mentioned above, glass plates on which electrical circuits and other components are incorporated require extremely high surface properties, as even slight scratches or contamination on the surface can cause disconnections or patterning defects. Consequently, the laminating paper used between these glass plates also requires excellent quality (cleanliness) to prevent even slight scratches or contamination on the glass plate surface. One way to obtain high-quality laminating paper is to increase the virgin pulp content. Therefore, virgin pulp is generally used as the raw material for laminating paper. On the other hand, from the perspective of environmental considerations and cost reduction, it is also possible to use recycled paper pulp as the raw material for laminating paper. However, deinked pulp (DIP), which is a common type of recycled paper pulp, can contain various foreign substances and adhesives such as ink from printed materials, metal staples from staplers that fasten newspapers, glue from book spines, sand and metal dust from truck transport, and rubber from conveyor belt transport. Although such foreign matter and adhesives are captured by circular-hole or slit-type screen filters during the papermaking process, their small size compared to the filter diameter prevents complete removal, resulting in some remaining on the surface of the glass plate interleaving paper. When glass plates are stacked with such interleaving paper, it can easily cause disconnections when wiring or other connections are formed on the glass plate surface. Therefore, even trace amounts of such foreign matter in the glass plate interleaving paper can be problematic.

[0017] Furthermore, focusing on the handling characteristics of the interleaving paper, if the interleaving paper is too stiff, it is prone to folding back, and when removing the glass plates from the glass plate packaging, the interleaving paper cannot be pressed against the side of the glass plate laminate, potentially causing the interleaving paper to be removed along with the glass plates. On the other hand, if the interleaving paper is too weak, it may result in poor handling during use.

[0018] In response to this, the present inventors have found that, according to the glass plate interleaving paper of this embodiment, it is possible to obtain glass plate interleaving paper that can suppress scratches and contamination of glass plates even while containing pulp derived from recycled paper, can further suppress problems when unpacking the glass plate laminate, and has good handling properties during use.

[0019] The reason for this can be considered as follows: First, as mentioned above, glass plate lamination requires excellent quality, so the recycled paper used for it tends to have fewer foreign materials and is of similarly excellent quality. As a result, glass plate lamination containing virgin pulp and recycled pulp derived from recycled glass plate lamination remains of excellent quality despite containing recycled pulp recovered from waste paper.

[0020] Furthermore, by having a deinked pulp (DIP) content of 0.1% by mass or less, the inclusion of foreign matter that can cause quality degradation in the lamination paper is suppressed, and the quality of the lamination paper is further guaranteed. In addition, during the re-disintegration and beating process of the recycled glass lamination paper, fiber cutting and fibrillation can be promoted. For example, lamination paper containing fibers that have undergone cutting tends to have relatively low tensile strength, while lamination paper containing fibers that have undergone fibrillation tends to have relatively high tensile strength. Thus, by manufacturing lamination paper using recycled pulp derived from recycled glass lamination paper and adjusting the conditions appropriately, the fiber length and degree of fibrillation are appropriately adjusted. Therefore, it is believed that the glass lamination paper according to this embodiment, which contains such recycled pulp and has an appropriately adjusted content, achieves both appropriate fold-back properties and excellent handling properties.

[0021] Furthermore, in order to obtain glass plate lamination paper that achieves both appropriate fold-back properties and excellent handling properties without using recycled pulp, it is necessary to perform special treatments such as making notches in the lamination paper, or to drastically increase the beating treatment of a portion of the raw pulp, or to make detailed adjustments to the conditions depending on the pulp, which results in lower productivity. On the other hand, the glass plate lamination paper according to this embodiment achieves both appropriate fold-back properties and excellent handling properties without undergoing these treatments. However, this does not in any way prevent these treatments from being performed on the glass plate lamination paper according to this embodiment or in its manufacturing process as needed.

[0022] The laminate for glass plates according to this embodiment includes virgin pulp and recycled pulp.

[0023] (Virgin pulp) In this specification, virgin pulp refers to pulp manufactured from wood or other materials, rather than pulp made from paper or recycled paper.

[0024] The specific type of pulp used in virgin pulp is not particularly limited and can be appropriately selected according to the characteristics required for lamination for glass plates. Virgin pulp may be made by using one type of pulp alone or by using multiple types of pulp in combination. Examples of pulp types include chemical pulps such as kraft pulp (KP), sulfite pulp (SP), and soda pulp (AP), mechanical pulps such as wood pulp (GP), thermomechanical pulp (TMP), and chemothermetic pulp (CTMP), and semi-chemical pulps such as chemigland pulp (CGP) and semi-chemical pulp (SCP), which are intermediate mechanical and chemical pulps. The pulp may be bleached or unbleached. For example, among KP types, bleached hardwood kraft pulp (LBKP), bleached softwood kraft pulp (NBKP), unbleached hardwood kraft pulp (LUKP), and unbleached softwood kraft pulp (NUKP) can be used.

[0025] Since high cleanliness is required for lamination paper for glass plates, bleached kraft pulp (LBKP and NBKP), which has been bleached and in which components such as resin derived from lignin have been washed away, is particularly preferred as the raw material pulp. In addition, hardwoods generally have shorter fiber lengths than softwoods, and softwood tends to produce paper with higher rigidity. Therefore, from the viewpoint of obtaining the effects of the present invention more effectively, softwood pulp is particularly preferred.

[0026] The virgin pulp content in glass plate lamination is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, from the viewpoint of improving handling properties. On the other hand, from the viewpoint of providing good re-folding properties, the virgin pulp content is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. The virgin pulp content is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and even more preferably 30 to 70% by mass.

[0027] (Recycled pulp) In this specification, recycled pulp refers to pulp recovered from waste paper. In this embodiment, the recycled pulp is recycled pulp derived from waste paper used for glass plate lamination. In this specification, "recycled pulp derived from waste paper used for glass plate lamination" may be simply referred to as "recycled pulp." By including recycled pulp derived from waste paper used for glass plate lamination in the glass plate lamination, glass plate lamination of excellent quality can be obtained while still containing pulp recovered from waste paper.

[0028] In this specification, "recycled glass plate interleaving paper" refers to recycled paper used as glass plate interleaving paper, that is, glass plate interleaving paper after being interposed between glass plates, as well as waste paper during the glass plate interleaving paper manufacturing process and waste paper of glass plate interleaving paper that was not used in the glass stacking process, etc. Recycled glass plate interleaving paper may be a combination of several types of these.

[0029] The specific type of pulp used in recycled pulp can be appropriately selected according to the characteristics required for use as laminating paper for glass plates, just as with virgin pulp, and the same applies to preferred types. Recycled pulp may be made by using one type of pulp alone, or by using multiple types of pulp in combination.

[0030] The types of pulp used in recycled pulp and virgin pulp may be different or the same. From the viewpoint of improving paper quality and the stability of papermaking conditions, it is preferable that a large proportion of fibers with relatively similar fiber lengths and widths are included in the laminated paper. For this reason, it is preferable, for example, to use the same type of pulp for both virgin pulp and recycled pulp, or to use hardwood pulp for both, or softwood pulp for both.

[0031] The recycled pulp content in the glass plate lamination paper is preferably 10% by mass or more, more preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more, from the viewpoint of ensuring good fold-back properties of the lamination paper. Furthermore, a high recycled pulp content is also preferable from the viewpoint of environmental considerations and improved productivity. When deinked pulp (DIP), which is commonly used as recycled pulp derived from waste paper, is incorporated into the lamination paper, there is a trade-off between productivity (cost reduction) and quality (cleanliness), making it difficult to obtain glass plate lamination paper that balances both quality and productivity. On the other hand, in this embodiment, by using recycled pulp derived from waste glass plate lamination paper, it is possible to obtain lamination paper with a relatively high recycled pulp content while maintaining excellent quality. From the viewpoint of improving the handling properties of the lamination paper, the recycled pulp content is preferably 90% by mass or less, more preferably 85% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less. The recycled pulp content is 10 to 90% by mass, preferably 20 to 85% by mass, more preferably 30 to 80% by mass, and even more preferably 40 to 75% by mass.

[0032] As mentioned above, compared to softwood pulp, laminated paper made with hardwood pulp tends to have lower rigidity. Therefore, if the amount of hardwood pulp used is too high, or if the amount of recycled pulp made from hardwood pulp is too high, the rigidity of the laminated paper may become too low, causing the paper to sag during transport or handling, hindering transport. Considering these points, when laminated paper contains recycled pulp made from hardwood, the content of recycled pulp made from hardwood is more preferably 10% to 70% by mass, even more preferably 20% to 60% by mass, and particularly preferably 30% to 50% by mass.

[0033] In contrast, coniferous pulp has a relatively long fiber length, and laminations made using it tend to have high rigidity. Considering this, when laminations contain recycled pulp made from coniferous trees, the content of recycled pulp made from coniferous trees is more preferably 20% to 90% by mass, even more preferably 30% to 80% by mass, and particularly preferably 40% to 70% by mass.

[0034] (Deinked pulp) The deinked pulp (DIP) content in the glass plate lamination paper is 0.1% by mass or less. In this specification, deinked pulp (DIP) refers to pulp from which the ink has been separated by dust removal and deinking treatment using waste paper as raw material, and more specifically, it refers to recycled pulp derived from waste paper such as newspapers, magazines, and flyers. By having a deinked pulp (DIP) content of 0.1% by mass or less, the amount of foreign matter that can cause a deterioration in quality in the lamination paper can be suppressed, and the quality of the lamination paper is ensured. The deinked pulp (DIP) content is preferably 0.05% by mass or less, and more preferably 0.02% by mass or less. The lower the deinked pulp (DIP) content, the better, and it may even be 0% by mass. The deinked pulp (DIP) content is preferably 0 to 0.1% by mass, more preferably 0 to 0.05% by mass, and even more preferably 0 to 0.02% by mass. The deinked pulp (DIP) content in glass plate laminating paper can be measured, for example, by evaluating ISO whiteness, residual ink content, and impurity content.

[0035] The glass plate lamination paper according to this embodiment may be glass plate lamination paper made from virgin pulp and recycled pulp derived from used glass plate lamination paper. For example, the ISO whiteness measured according to JIS P 8148:2018 is 90% or higher, and the amount of impurities measured according to JIS P 8208:1998 is 1 mm 2 If the value is less than / kg, it can be determined that the laminating paper for glass plates consists of virgin pulp and recycled pulp derived from used laminating paper for glass plates.

[0036] The Clark stiffness of glass plate lamination in the papermaking direction is 40 cm 3 It is preferable that it be less than / 100. Glass sheets with interleaving paper for glass sheets are transported from a glass manufacturing plant to a glass sheet processing and assembly plant, for example, stacked on a packaging pallet. At the glass sheet processing plant, the sheets are removed one by one from the packaging pallet by a removal device. In this process, the glass sheet is picked up by the glass suction part of the removal device, and the edges of the interleaving paper are pressed down to remove only the glass sheet. Then, the interleaving paper is removed by the interleaving paper suction part, and this process is repeated. Therefore, the edges of the interleaving paper for glass sheets must be folded in advance downwards (to the opposite side of the direction in which the glass sheet is removed) from the plane formed by the main surface of the glass sheet that is in contact with the interleaving paper. Incidentally, the stiffer the interleaving paper, the more likely it is to return to its original shape (flat state) over time. If the interleaving paper is too stiff, when removing the glass plate, the edge of the topmost interleaving paper may not be able to be pressed against the side of the glass plate laminate, resulting in the topmost interleaving paper being removed together with the glass plate, or the interleaving paper flying off when air is supplied. If the Clark stiffness is set within the above range, the paper will not be too stiff, and it will be easy to remove the interleaving paper properly.

[0037] In other words, the Clark stiffness of the glass plate laminate with respect to the papermaking direction is 40 cm 3 It is preferable that it be less than / 100, and 39cm 3 / 100 or less is more preferable, and 38.5cm 3It is more preferable that it is 100 or less. The Clark stiffness in the paper-making direction is 30 cm from the viewpoint of improving the handling property of the laminated paper. 3 It is preferably 100 or more, and 33 cm 3 It is more preferably 100 or more, and 35 cm 3 It is more preferably 100 or more. The Clark stiffness is 30 cm 3 It is preferably 100 or more and less than 40 cm 3 It is preferably less than 100, and more preferably 33 to 39 cm 3 It is more preferably 35 to 38.5 cm 3 It is more preferably 10 or more.

[0038] Generally, in the process of producing paper, it is known that fibers tend to align along the paper-making direction (flow direction, MD: Machine Direction) of the paper. As a result, streaks along the paper-making direction occur in the paper. The longitudinal streaks are in the paper-making direction of the paper, and the transverse streaks are in the direction orthogonal to the paper-making direction. Since the fibers are aligned, it is more difficult to bend in the direction orthogonal to the longitudinal streaks than to bend along the longitudinal streaks. When bent with the same force, the former is more likely to rebound. Therefore, the Clark stiffness with respect to the paper-making direction (Clark stiffness of the longitudinal streaks) is particularly important. The laminated paper for a glass plate according to the present embodiment is likely to have an appropriate Clark stiffness by appropriately adjusting the content of the recycled pulp. The Clark stiffness can be measured by the method described in the examples below.

[0039] The aspect ratio obtained by dividing the Clark stiffness in the paper-making direction (Clark stiffness of the longitudinal streaks) by the Clark stiffness in the direction orthogonal to the paper-making direction (Clark stiffness of the transverse streaks) is preferably 1.80 or more and 2.40 or less. As mentioned above, generally, the stiffness in the machine direction (MD) is greater than the stiffness in the cross-machine direction (CD). Furthermore, when unpacking a glass plate package, the interleaving paper is folded, and in this case, three or more sides of the interleaving paper may be folded. In this case, the CD direction is relatively easy to bend, while the MD direction is difficult to bend and is also easy to unfold. The smaller the aspect ratio (MD / CD), the smaller the difference in stiffness between the two directions, making it easier to bend in both directions and harder to unfold. Also, the smaller the aspect ratio, the better the dimensional stability of the paper, and the smaller the dimensional shrinkage and expansion during drying and wetting, making it suitable as interleaving paper for glass plates. From this viewpoint, an aspect ratio of 2.40 or less is preferred, 2.30 or less is more preferred, and 2.20 or less is even more preferred.

[0040] On the other hand, if the fiber orientation of the laminated paper becomes too close to isotropic, when curling occurs due to moisture, it becomes necessary to consider curling not only in the MD direction but also in the CD direction. From the viewpoint of suppressing this, an aspect ratio of 1.80 or higher is preferred, 1.90 or higher is more preferred, and 2.00 or higher is even more preferred. An aspect ratio of 1.80 to 2.40 is preferred, 1.90 to 2.30 is more preferred, and 2.00 to 2.20 is even more preferred.

[0041] The glass plate lamination according to this embodiment is a lamination in which the fiber orientation is appropriately adjusted by manipulating the J / W ratio of the speed J at which the paper pulp is discharged to the papermaking wire and the wire speed W, which makes it easier to obtain a suitable aspect ratio. The J / W ratio is preferably 0.90 to 1.10, more preferably 0.95 to 1.05, and even more preferably 0.98 to 1.02. The glass plate lamination according to this embodiment contains a certain amount of relatively short fibers compared to virgin pulp, making it easier to achieve a uniform form. Therefore, by using recycled glass plate lamination paper and adjusting the J / W ratio to a value close to 1, it is easy to obtain a suitable aspect ratio for the embodiment of this application.

[0042] In the fiber width distribution of the disintegrated pulp obtained by disintegrating glass plate laminating paper, when the median fiber width is Me, it is preferable that the proportion of fibers with a fiber width of (Me-0.5Me) or more and (Me+0.5Me) or less is 70% or more, more preferably 75% or more, and even more preferably 80% or more. The upper limit of this proportion is not particularly limited and may be 100%. That is, the above proportion is preferably 70-100%, more preferably 75-100%, and even more preferably 80-100%. The above percentage refers to the proportion of fibers within the range of Me ± Me × 50%. A percentage of 70% or more means that most of the pulp constituting the laminated paper has a similar fiber width. Typically, if the above percentage is 70% or more, it can be said that the majority of the pulp constituting the laminated paper (for example, 80% by mass or more) is either softwood pulp or hardwood pulp. In this case, the laminated paper will contain a large amount of pulp of a consistent standard, thus stabilizing the papermaking conditions and paper quality. The fiber width distribution of the disintegrated pulp can be measured by the method described in the examples below.

[0043] The glass plate laminating paper is prepared by disintegrating the glass plate laminating paper and classifying the length-weighted average fiber length distribution (hereinafter also simply referred to as the fiber length distribution) of the disintegrated pulp into the following classes (A) to (F). When the percentage of fibers belonging to each class is expressed as (a) to (f), it is preferable that at least one of (b)+(c), (c)+(d), and (d)+(e) is 50% or more, more preferably 60% or more, and even more preferably 70% or more. Note that "expressing the percentage of fibers belonging to each class as (a) to (f)" means that the percentage of fibers belonging to class (N) is expressed as (n) (N=A~F, n=lowercase alphabet corresponding to N). (A) Greater than 0mm and less than 0.2mm (B) 0.2 mm or more and less than 0.6 mm (C) 0.6 mm or more and less than 1.2 mm (D) 1.2 mm or more and less than 2.0 mm (E) 2.0 mm or more and less than 3.2 mm (F)3.2mm or more and 7.6mm or less

[0044] Meeting the above requirements means that most of the pulp making up the laminated paper is at a similar level in terms of fiber length, and that the fiber length is within an appropriate range. Typically, if the above requirements are met, it can be said that the majority of the pulp constituting the lamination paper (e.g., 80% by mass or more) is either softwood pulp or hardwood pulp. In this case, the lamination paper will contain a large amount of pulp of uniform quality, thus stabilizing the papermaking conditions and paper quality. It should be noted that the inclusion of a large amount of pulp of uniform quality in glass plate lamination paper does not necessarily mean that the fiber length distribution can be fitted to a relatively small number of normal distributions (e.g., around 2 or 3). Since the raw material system of the glass plate lamination paper according to this embodiment consists of two or more types, the fiber length distribution may be relatively smooth or may be a shape that can be fitted to a superposition of a relatively large number of normal distributions. Even in this case, if the above requirements are met, it can be determined that the paper contains a large amount of pulp of uniform quality. The length-weighted average fiber length distribution of the disintegrated pulp can be measured by the method described in the examples below.

[0045] Generally, hardwood pulp has a median fiber width Me of 10-25 μm, and the maximum frequency of the fiber length distribution often falls within the range (C) above. Conversely, softwood pulp has a median fiber width Me of 20-35 μm, and the maximum frequency of the fiber length distribution often falls within the range (E) above.

[0046] For glass plate lamination, it is preferable that the concentrations of each element, magnesium, silicon, titanium, iron, and chromium, as measured by X-ray fluorescence analysis, satisfy all of the following conditions (1) to (5). (1) Magnesium 200 ppm or less (2) Silicon 300 ppm or less (3) Titanium 0.10 ppm or less (4) Iron: 0.50 ppm or less (5) Chromium 1.0 ppm or less If all of the above conditions (1) to (5) are met, the concentration of elements that may be contained due to contamination of the glass plate laminating paper or foreign matter in the laminating paper is relatively low, and it can be determined that the glass plate laminating paper has excellent cleanliness and high quality. The glass plate laminating paper according to this embodiment contains recycled pulp derived from glass plate laminating paper, thereby achieving excellent quality despite containing recycled pulp derived from waste paper.

[0047] In other words, in laminated paper for glass plates, the concentrations of each element, magnesium, silicon, titanium, iron, and chromium, as measured by X-ray fluorescence analysis, are preferably within the following ranges. The magnesium concentration is preferably between 0 and 200 ppm. That is, the magnesium concentration is preferably 200 ppm or less, more preferably 150 ppm or less, and even more preferably 100 ppm or less. The silicon concentration is preferably 0 to 300 ppm. That is, the silicon concentration is preferably 300 ppm or less, more preferably 200 ppm or less, and even more preferably 100 ppm or less. The titanium concentration is preferably 0 to 0.10 ppm. That is, the titanium concentration is preferably 0.10 ppm or less, more preferably 0.05 ppm or less, and even more preferably 0.01 ppm or less. The iron concentration is preferably 0 to 0.50 ppm. That is, the iron concentration is preferably 0.50 ppm or less, more preferably 0.25 ppm or less, and even more preferably 0.01 ppm or less. The chromium concentration is preferably 0 to 0.10 ppm. That is, the chromium concentration is preferably 0.10 ppm or less, more preferably 0.05 ppm or less, and even more preferably 0.01 ppm or less. X-ray fluorescence analysis can be performed using the method described in the examples below.

[0048] The resin content is an indicator that represents the amount of organic matter other than cellulose, such as lignin, contained in the glass plate lamination paper. In this embodiment, the resin content of the glass plate lamination paper is preferably 0.5% or less, more preferably 0.3% or less, even more preferably 0.1% or less, and particularly preferably 0.05% or less. By suppressing the resin content, it is possible to suppress the adhesion of organic matter (resin components) in the glass plate lamination paper to the glass plate and cause glass contamination. The resin content can be measured in accordance with ISO 624-1974.

[0049] Wood pulp may contain silicone, for example, derived from defoaming agents used in the washing process. If silicone is present in the interleaving paper for glass plates, it may transfer to the glass plates and cause contamination. Therefore, the amount of silicone in the interleaving paper for glass plates is preferably less than 0.5 ppm, more preferably 0.25 ppm or less, and even more preferably 0.1 ppm or less. By keeping the amount of silicone within the above range, contamination of the glass plates by silicone can be suppressed. The amount of silicone can be measured, for example, by the following method. Cut 1g of laminated paper into pieces no larger than 20mm x 20mm, perform Soxhlet extraction with hexane for 4 hours, then reduce the solvent of the extract using an evaporator, and dissolve it in approximately 1mL of deuterated chloroform. 1 ¹H-NMR measurements are performed. For NMR measurements, a Bruker AVANCE III 600 is used, for example. For quantification, a calibration curve is created using a deuterated chloroform solution of polydimethylsiloxane as a standard, and quantification is performed using an external standard method.

[0050] The basis weight of the laminating paper for glass plates is 30-100 g / m². 2 This is preferable. If the basis weight of the glass plate laminate in this embodiment is too low, the strength may decrease and it may become easily torn. Therefore, the basis weight of the glass plate laminate in this embodiment is 30 g / m². 2 The above is preferable, 35 g / m 2 The above is more preferable: 40 g / m 2 The above is even more preferable, 45 g / m 2 The above are particularly preferable. On the other hand, a higher basis weight leads to increased weight, and also increases the stacking height when the glass plate laminate and glass plate are laminated together, thus reducing the number of sheets that can be stored in a container of a predetermined height. Therefore, the basis weight of the glass plate laminate in this embodiment is 100 g / m². 2 The following is preferable: 90 g / m 2 The following is more preferable: 80g / m 2 The following is even more preferable: 70 g / m 2 The following are particularly preferable. Basis weight can be measured in accordance with JIS P 8124:2011. Furthermore, from the same viewpoint as above, the thickness of the laminate for the glass plate in this embodiment is preferably 30 to 150 μm.

[0051] Since the glass plates laminated with the glass plate laminate of this embodiment are usually rectangular, it is preferable that the glass plate laminate of this embodiment is also rectangular. Furthermore, in order to be usable for laminating large glass plates, it is preferable that the length of at least one side of the rectangular glass plate laminate of this embodiment is 500 mm or more, more preferably 1000 mm or more, even more preferably 1500 mm or more, and particularly preferably 2200 mm or more. There is no particular upper limit, but for example, it is 4000 mm or less. For example, if the glass plate is rectangular and measures 2200mm x 2500mm, the laminate for the glass plate should preferably be rectangular in shape, approximately 2280mm x 2580mm. When the glass plate is rectangular, the length of each side of the laminate for the glass plate should preferably be approximately 1.02 to 1.05 times the length of the corresponding side of the glass plate.

[0052] The glass plate lamination paper of this embodiment may have various chemicals added internally or externally (coating, impregnation, etc.) to the extent that the effects of the present invention are achieved. Examples of chemicals that may be added internally or externally to the glass plate lamination paper include aluminum sulfate, defoamers, fixatives, paper strength enhancers, yield enhancers, coagulants, surfactants, sizing agents, antistatic agents, slime control agents, dryer release agents, polyvinyl alcohol, polycrylamide, starch, cellulose derivatives such as CMC, and fillers (talc, clay, titanium dioxide, calcium carbonate, etc.).

[0053] (Method of manufacturing lamination paper for glass plates) The following describes an example of a manufacturing method for glass plate laminate according to this embodiment, comprising a preparation step of preparing pulp as the raw material, a preparation step of manufacturing a pulp slurry from the pulp, and a papermaking step of making glass plate laminate from the pulp slurry. Note that the manufacturing method for glass plate laminate according to this embodiment is not limited to the example described below.

[0054] The preparation process involves preparing the pulp raw material for the laminated paper used for glass plates. The raw pulp includes at least virgin pulp and recycled pulp derived from waste paper used for glass plates. The specific types of virgin pulp and recycled pulp are as described above.

[0055] While virgin pulp can be prepared using known methods, insufficient washing and sorting of the pulp, or poor quality water used during washing, can lead to contamination or insufficient removal of foreign matter. Furthermore, if proper control is not implemented in the papermaking process described later, foreign matter may be introduced from environmental dust, equipment, papermaking tools, etc. Therefore, it is desirable to properly control the quality of the pulp used and the quality control at each stage of the process.

[0056] This section describes the preparation of recycled pulp derived from waste glass lamination paper. For example, if the raw pulp for glass lamination paper that becomes waste glass lamination paper is all virgin pulp, first, the virgin pulp is disintegrated and beaten, and then glass lamination paper is manufactured by papermaking. The manufactured glass lamination paper is used, for example, as interposition between multiple glass plates in a glass plate laminate when glass plates are shipped. The glass lamination paper that is recovered after use is obtained as waste glass lamination paper. As mentioned above, waste glass lamination paper may also be waste paper from the papermaking process of glass lamination paper, or waste glass lamination paper that was not used in the glass stacking process, etc. In this case, the recovered waste paper is obtained as waste glass lamination paper.

[0057] While there are no specific limitations on the method for recovering waste interleaving paper for glass plates, using interleaving paper that has been carelessly discarded during various processes may result in contamination by dust from the floor or air, glass cullet fragments, etc. Therefore, it is desirable that the interleaving paper for glass plates be recovered using an interleaving paper grabbing device that has clean suction pads and gripping clamps, and uses components that are unlikely to contaminate the interleaving paper, such as oil-free pumps, and that only the interleaving paper be collected in an orderly manner in a dedicated container for interleaving paper recovery.

[0058] Furthermore, it is desirable that the paper recycling containers be highly airtight. This is to prevent quality deterioration due to contamination by dust from containers or roads during transport, and to prevent the paper from becoming extremely difficult to handle and reuse due to high humidity at sea, which can result from excessive moisture absorption. Furthermore, it is preferable to use laminated paper collected from an environment cleaner than Class 10000.

[0059] Used glass plate laminating paper may be used as recycled pulp derived from it as is after collection, or it may be used as recycled pulp derived from it after undergoing various treatments such as bleaching, washing, and dust removal. For dust removal, for example, organic matter may be removed by flotation, or organic and inorganic matter may be removed according to size and weight using screens, cyclone filters, etc. Multiple methods may be combined or multi-stage, and the removal performance improves with more stages. By performing treatments such as bleaching, washing, and dust removal, the glass plate laminating paper, which was originally of relatively high quality, can be made into an even higher quality raw material, and the amount of foreign matter may be less than when laminating paper is manufactured using 100% virgin pulp, which is preferable.

[0060] As mentioned above, using deinked pulp such as recycled newspaper to manufacture laminated paper results in a significant deterioration of quality. On the other hand, recycled pulp derived from recycled glass plate laminated paper, preferably collected and stored using the methods described above, contains significantly less foreign matter and is of superior quality compared to general waste paper such as recycled newspaper.

[0061] In the preparation process, the raw materials are diluted with water or other liquids to disintegrate them, and then beaten appropriately using a conical refiner or double disc refiner to obtain a raw material liquid (pulp slurry). In this process, the various chemicals mentioned above may be added internally. During the beating process, the beating conditions should be changed according to the type of pulp used and the characteristics of the glass plate lamination paper to be produced, in other words, the characteristics of the disintegrated pulp. Free beating, which primarily cuts the fibers, and viscous beating, which primarily swells and fibrillates the fibers, should be performed as appropriate. Virgin pulp and recycled pulp may be disintegrated and beated together as raw material pulp, but it is preferable to disintegrate and beate each type separately, and then mix them after they have become a pulp slurry, as this allows for appropriate disintegration and beating conditions for each type of pulp. For example, hardwood pulp is preferably beaten to a freeness of 250-600 mL CSF, and softwood pulp is preferably beaten to a freeness of 300-650 mL CSF. Furthermore, the concentration of the pulp slurry is preferably 0.5-2% by mass.

[0062] In the papermaking process, the obtained pulp slurry is used to make paper using, for example, a wire screen paper machine, a cylinder screen paper machine, an inclined wire paper machine, or a twin wire paper machine. After passing through the wet end, the wet paper is dewatered and dried using a multi-cylinder dryer or a Yankee dryer. If necessary, the aforementioned chemicals may be applied or impregnated using a roll coater or a blade coater. Various calenders such as soft calenders and super calenders may also be used online or offline. The laminate for glass plates of this embodiment is obtained as described above.

[0063] (Laminated glass plate) The glass plate laminate according to this embodiment is a glass plate laminate in which a plurality of glass plates are stacked, and a glass plate interleaving paper according to this embodiment is provided between the glass plates. In other words, as shown in Figure 1, the glass plate laminate 10 is a laminate in which the aforementioned glass plate interposing paper 1 is interposed between multiple glass plates 2.

[0064] The glass plate laminate 10 shown in Figure 1 has a structure in which five sheets of glass plate interleaving paper 1 and five glass plates 2 are stacked alternately. The number of layers of glass plate interleaving paper 1 and glass plates 2 is not limited to this and can be appropriately changed according to various conditions such as the strength and size of the glass plates 2 and the size of the packaging container. The number of glass plates stacked can be two or more, with an upper limit of, for example, 300 or less. Typically, the glass plate laminate 10 is stacked so that its total mass is 2000 kg or less. The number of layers of glass plates 2 and glass plate laminate 1 is usually either the same number of glass plates 2 and glass plate laminate 1, or the number of glass plate laminate 1 is one more than the number of glass plates 2.

[0065] The uses of glass plate 2 are not particularly limited, but glass plate 2 is preferably a glass plate used in connection with the manufacture of liquid crystal products and semiconductor products, where it is required that the surface be kept highly clean, such as a glass plate used for flat panel displays such as liquid crystal display glass substrates and organic EL glass substrates, a glass plate used for semiconductor packaging, and a glass plate used for electronic devices such as solar cells.

[0066] The material of glass plate 2 is not particularly limited and can be appropriately selected according to the application, but examples include soda-lime glass, aluminosilicate glass, borosilicate glass, alkali-free aluminosilicate glass, and quartz glass. It is also possible to use glass plates made of glass that absorbs ultraviolet or infrared rays, or tempered glass.

[0067] The shape, size, and thickness of glass plate 2 are not particularly limited; any shape, size, and thickness that allows for stacking and storage of two or more plates is acceptable. The shape of the glass plate 2 may be, for example, a flat plate as shown in Figure 2, or it may be a curved surface with curvature on all or part of its surface. The thickness of glass plate 2 can be adjusted as appropriate depending on the application, but for example, it is between 0.01 and 10 mm. The size of the glass plate may be, for example, that of the 8th generation (2200mm x 2500mm) developed in recent years. In this case, the thickness of the glass plate is preferably 0.2 to 0.8 mm for ensuring strength, and more preferably about 0.3 to 0.7 mm. Furthermore, the glass plate 2 may be laminated glass in which multiple glass plates are bonded together with an interlayer in between.

[0068] The manufacturing method for the glass plate 2 is not particularly limited, but for example, it may be formed to a predetermined thickness by methods such as the press method, down-draw method, or float method, and after slow cooling, it may be processed by grinding, polishing, etc., to obtain a glass plate of a predetermined size and shape.

[0069] Furthermore, the glass plate 2 may have a functional thin film on its surface. Specifically, the functional thin film is a conductive film (such as tin-doped indium oxide (ITO), zinc oxide (ZnO), tin oxide (SnO2), Ag, or a film having a Cr / Cu / Cr structure) or a heat-shielding film (such as a layer having an oxide (e.g., zinc oxide, titanium oxide, ITO, etc.) / Ag / oxide structure). Here, zinc oxide may be doped with Al, Ga, or hydrogen. Tin oxide may be doped with F or Sb. Ag may be doped with Pd or Au.

[0070] (Packaged glass sheets) The glass plate packaging body of this embodiment comprises a glass plate laminate according to this embodiment and a pallet on which the glass plate laminate is placed. When transporting or storing glass plates, glass plates and glass plate interlining are stacked alternately to form a laminate, which is then placed on a pallet for storage and then packaged to form a package (glass plate package). There are two types of glass plate packages: a horizontal type in which the glass plates are stacked horizontally, and a vertical type in which the glass plates are stacked upright at an angle. The present invention can be applied to either type. Figure 2 shows a schematic configuration of an example of a vertical type glass plate package. Figure 3 shows a schematic configuration of an example of a horizontal type glass plate package.

[0071] The glass plate packaging 30 shown in Figure 2 is a glass plate laminate 10, which is made by stacking multiple glass plates 2 with glass plate interposing paper 1 in between, on a pallet 31 and then packaging it. It is preferable that glass plate interposing paper 1 is also placed between the pallet 31 and the glass plates 2. The pallet 31 is a known vertical stacking type pallet for packaging glass plates, and has a base 33, an inclined platform 32 erected on the upper surface of the base 33, and a mounting platform 34 placed on the upper surface of the base 33.

[0072] One vertical surface of the inclined platform 32 (the contact surface with the glass plate laminate 10; hereinafter also referred to as the "inclined surface") is inclined with respect to the vertical direction. The angle of this inclined surface (shown as α in Figure 2) should be such that the stacked glass plate laminate 10 can be stably loaded, stored, and transported, and is usually 85° or less with respect to the horizontal direction, for example, 85° to 70°.

[0073] Furthermore, the upper surface of the mounting base 34 is inclined downwards toward the inclined base 32 with respect to the horizontal direction. In the illustrated example, as one example, the upper surface of the mounting base 34 is configured to be at a 90° angle with respect to the inclined surface of the inclined base 32.

[0074] In the pallet 31, the glass plates 2 are stacked on the upper surface of the mounting base 34 and leaning against the inclined surface of the inclined base 32. A glass plate interlining 1 is interposed between each glass plate. Alternatively, the surface of the frontmost glass plate may be covered with the glass plate interlining.

[0075] The glass plate packaging 50 shown in Figure 3 is a glass plate laminate 10, which is made by stacking multiple glass plates 2 with glass plate interposing paper 1 in between, on a pallet 51 and then packaging it. It is preferable that glass plate interposing paper 1 is also placed between the pallet 51 and the glass plates 2. The pallet 51 is a known horizontal glass plate packaging pallet and has a base 53 and a mounting platform 54 placed on the upper surface of the base 53. It also has support columns 52 for stacking pallets 51 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). [Examples]

[0076] The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. Examples 1 to 4 are examples, and Examples 5 to 10 are comparative examples. Hereafter, unless otherwise specified, the percentages of % and ppm indicating the content rate represent mass % and mass ppm, respectively.

[0077] (evaluation) The following evaluations were performed on the laminated paper for glass plates in each example. For each evaluation, samples were used that had been left to stand in air under standard conditions (23±1°C, 50±2RH%) in accordance with JIS P8111:1998 "Paper, cardboard and pulp - Standard conditions for conditioning and testing," and that had reached equilibrium with the water vapor in the test room under standard conditions after conditioning was complete. However, for evaluations of foldability, handling properties, and glass staining / scratch resistance, glass plate lamination paper was left to stand in an environment of 23±3°C and 50±10RH% humidity and used after conditioning.

[0078] (Basic weight) In accordance with JIS P8124:2011 "Paper and cardboard - Method for measuring basis weight", the basis weight of each example of laminated glass sheet [g / m²] 2 ] was measured.

[0079] (thickness) The thickness [μm] of the glass plate laminates for each example was measured in accordance with JIS P 8188:2014 "Paper and paperboard - Test methods for thickness, density and specific volume".

[0080] (Fiber length distribution, fiber width distribution) Measurements were performed using Valmet's FS5, in accordance with JIS P8226-2:2011 Pulp - Measurement of fiber length by automated optical analysis method. The pulp was dissociated using water purified to have an electrical conductivity of 0.25 mS / m or less at 25°C, according to the method specified in JIS P8220-1:2012 "Pulp - Dissociation methods - Part 1: Dissociation of chemical pulp". Glass plate laminating paper, torn into approximately 25mm x 25mm pieces, was added to 2000±25mL of water at 20±5℃. This was then added to a standard disintegrator and disintegrated until the fibers were completely dispersed to obtain disintegrated pulp. The obtained disintegrated pulp was analyzed using a fiber image analyzer (Valmet FS5, Valmet Inc.) to measure the fiber length classification, weighted average fiber length distribution, and fiber width distribution. The ISO fiber length range (0.20 to 7.0 mm) was used for the measurements, and the average value of five measurements per sample was used. (Median fiber width) The median was calculated from the frequency histogram of fiber widths using the following calculation. The cumulative frequency is taken from the bottom of the frequency distribution, and the class that is closer to this cumulative value and is more than half of the total frequency is defined as the class in which the median exists. If the lower limit of the class in which the median exists is X, the frequency is f, the width is C, the frequencies below X are F, and the total frequency is Ft, then the median Me is expressed by the following formula. Me = X + Cx(Ft / 2 - Ft) / f

[0081] (Clark stiffness) Clark stiffness was measured in accordance with JIS P8143:2009 Paper - Stiffness Test Method - Clark Stiffness Tester Method. Clark stiffness in the direction of papermaking was defined as Clark stiffness of the longitudinal ridges, and Clark stiffness in the direction perpendicular to the papermaking direction was defined as Clark stiffness of the transverse ridges. From the measured values ​​in each direction, the aspect ratio was calculated by dividing the Clark stiffness in the direction of papermaking (Clarke stiffness of the longitudinal ridges) by the Clark stiffness in the direction perpendicular to the papermaking direction (Clarke stiffness of the transverse ridges).

[0082] (X-ray fluorescence analysis) The concentrations of magnesium, silicon, titanium, iron, and chromium were measured using RIGAKU's Supermini200 wavelength-dispersive compact X-ray fluorescence analyzer. Five sheets of laminated paper, collected from adjacent locations, were stacked and measured.

[0083] (Silicone content) After cutting 1g of oven-dried laminated paper into pieces no larger than 20mm x 20mm, Soxhlet extraction is performed using hexane for 4 hours, then the solvent of the extract is reduced using an evaporator, and this is dissolved in approximately 1mL of deuterated chloroform. 1 ¹H-NMR measurements were performed. A Bruker AVANCE III 600 was used for the NMR measurements. For quantification, a calibration curve was created using a deuterated chloroform solution of polydimethylsiloxane as a standard, and quantification was performed using the external standard method.

[0084] (Rebounding property) A laminate of glass plates was obtained by stacking sheets of laminated paper on a 470mm x 370mm x 0.5mm glass plate, with the vertical grooves of the laminated paper protruding by 40mm, and then stacking 30 of these alternately. The protruding portion of the laminate was folded at a 60° angle from the glass plate plane, and then left to stand for 24 hours. After that, the angle at which the protruding portion of the topmost laminate unfolded from the 60° angle, i.e., the angle at which the protruding portion made contact with the glass plate plane after standing, was used to quantify the unfolding properties using the following formula, and the average value of three glass plate laminates was used for evaluation. Rebound property [%] = {(60 - angle after standing) / 60} × 100 The higher the value of the fold-back property, the more the folded laminated paper returns to a near-horizontal state, which is more likely to cause paper feeding problems. For example, a fold-back property of 40% or less is considered good, a value between 40% and 60% may result in paper feeding problems, and a value above 60% is considered problematic as it will result in paper feeding problems.

[0085] (Handling) After cutting the laminated paper from a roll to 2580mm x 2260mm, the laminated paper was fed on a conveyor belt and placed on glass. The glass plate and laminated paper were then transferred to a pallet using a transfer machine and stored. A test was conducted using 600 sheets, and the number of times a plate or paper collection failure occurred was used for evaluation. Examples of plate or paper collection failures include the laminated paper getting stuck between the conveyor rollers during feeding, or the laminated paper falling off the pallet or moving after being placed on the pallet, resulting in the laminated paper failing to protect the glass plate or failing to be held down. ○: No plate or paper feeding errors occurred. △: One to two instances of faulty plate / paper collection occurred. ×: There were three or more instances of faulty plate / paper collection.

[0086] (Glass staining, glass scratching) The prepared interleaving paper and the glass plates (AN100) after CeO2 polishing and washing were stacked alternately on a flat-stacking pallet to obtain a glass plate package consisting of 200 glass plates. The fabricated glass plate packaging was subjected to a random vibration test for 1 hour using a vibration testing machine in accordance with JIS Z0232:2004. The vibration conditions were those described in Annex Table A.1 of the same standard, simulating a typical transportation environment (mainly roads) with an acceleration power spectral density of 5.9 m / s². 2 It was done using (rms). The glass plates removed from the packaging were passed through a washing machine consisting of two rows of shower pipes supplied with pure water at a pressure of 1 MPa and a flow rate of 20 L / min. They were then dried with an air knife that sprayed clean dry air to obtain clean substrates. The surface of the cleaned substrate where wiring and other elements are formed was measured in Normal (1.0 μm) mode using a foreign object inspection machine for FPDs (Toray Engineering Co., Ltd., HS-830e), and the number of foreign objects and microscopic images of the foreign objects were obtained.

[0087] (Glass staining and scratching properties) Glass contamination and scratching properties were observed using an FPD foreign object inspection machine for foreign objects other than paper dust and for scratches, and evaluated according to the following evaluation criteria. ○: No contamination or damage has occurred at all; the level is completely fine. △: There is some contamination or damage, which may be problematic. ×: The contamination or damage is extensive and at a problematic level.

[0088] (Example 1) Commercially available LBKP (Laminated Birthweight Kettle) was beaten in a double disc refiner to prepare a 0.6% pulp slurry with a freeness of 550 mL CSF (Chemical Sulfate). This slurry was then used in a wire mesh paper machine to obtain laminated paper for glass plates. In the glass manufacturing process, glass plates AN100 (manufactured by AGC Inc.) and glass plates that had been polished and washed were alternately loaded onto glass plate pallets in a cleanroom to obtain a package. After transportation, this package was unpacked in a cleanroom in the LCD manufacturing process, the glass plates were flowed into the line, and the glass plates were collected using a glass plate gripping device and stored in a glass plate storage container to obtain recycled glass plate A pulp slurry made from recycled pulp was used as the first raw material, with 55% solid content. A pulp slurry made from commercially available LBKP (natural virgin pulp) beaten in a double disc refiner to a freeness of 550 mL CSF was used as the second raw material, with 45% solid content. These were mixed to prepare a 0.7% by mass pulp slurry. This slurry was then made into paper using a wire mesh paper machine, resulting in a basis weight of 52 g / m². 2 A laminate for glass plates with a paper thickness of 65 μm was obtained. The glass plate lamination paper in Example 1 exhibited good fold-back properties. Although the LBKP used as raw material contained talc and trace amounts of hard foreign matter, thorough washing and sorting were performed when using recycled pulp, resulting in a reduction in the amount of foreign matter compared to Example 5. Consequently, excellent evaluation results were obtained regarding glass contamination and glass scratching resistance.

[0089] (Example 2) Using commercially available NBKP as the natural virgin pulp, a pulp slurry was prepared with a freeness of 520 mL CSF., and papermaking was performed to produce glass plate lamination paper, which was then used to obtain recycled glass plate lamination paper in the same manner as in Example 1. Furthermore, glass plate lamination paper was obtained in the same manner as in Example 1, except that 60% of the solid content of the recycled pulp slurry was used as the first raw material, and 40% of the solid content of the pulp slurry made with commercially available NBKP as the natural virgin pulp with a freeness of 520 mL CSF. was used as the second raw material. The resulting laminated paper had a basis weight of 51 g / m². 2The paper thickness was 69 μm. The fold-back properties of the glass plate lamination in Example 2 were good. Because the raw material was derived from NBKP, the fold-back was slightly greater compared to Example 1. The NBKP used as raw material contained trace amounts of hard foreign matter, but because sufficient washing and sorting were performed when using recycled pulp, the amount of foreign matter was reduced compared to Example 6, resulting in a higher quality product.

[0090] (Example 3) Laminating paper for glass plates was obtained in the same manner as in Example 1, except that 20% of the solid content of the pulp slurry of recycled pulp (recycled pulp L material) obtained in the same manner as in Example 1 was used as the first raw material, 40% of the solid content of the pulp slurry of virgin pulp (natural virgin pulp N material) obtained in the same manner as in Example 2 was used as the second raw material, and 40% of the solid content of the pulp slurry of recycled pulp (recycled pulp N material) obtained in the same manner as in Example 2 was used as the third raw material. The resulting laminating paper had a basis weight of 55 g / m². 2 The paper thickness was 70 μm. The glass plate laminate in Example 3 exhibited good fold-back properties. Furthermore, it received excellent evaluation results in terms of handling properties, glass contamination resistance, and glass scratch resistance.

[0091] (Example 4) Laminating paper for glass plates was obtained in the same manner as in Example 1, except that 15% of the solid content of the pulp slurry of virgin pulp (natural virgin pulp L material) obtained in the same manner as in Example 1 was used as the first raw material, 35% of the solid content of the pulp slurry of recycled pulp (recycled pulp L material) obtained in the same manner as in Example 1 was used as the second raw material, 15% of the solid content of the pulp slurry of virgin pulp (natural virgin pulp N material) obtained in the same manner as in Example 2 was used as the third raw material, and 35% of the solid content of the pulp slurry of recycled pulp (recycled pulp N material) obtained in the same manner as in Example 2 was used as the fourth raw material. The resulting laminating paper had a basis weight of 48 g / m². 2The paper thickness was 63 μm. The glass plate laminate of Example 4 showed good fold-back properties. In addition, it received excellent evaluation results for handling properties, glass staining resistance, and glass scratching resistance. In the glass plate laminate of Example 4, although the proportion of softwood pulp is greater than that of hardwood pulp, the proportion of hardwood pulp is relatively large, so (b)+(c), (c)+(d), and (d)+(e) are all less than 50%. For this reason, it may be difficult to adjust the conditions during the manufacturing of the glass plate laminate.

[0092] (Example 5) Laminating paper for glass plates was obtained in the same manner as in Example 1, except that 5% of recycled pulp solids was used as the first raw material and 95% of natural virgin pulp solids was used as the second raw material. The resulting laminating paper had a basis weight of 54 g / m². 2 The paper thickness was 80 μm. The fold-back properties of the glass plate laminate in Example 5 were inferior to those of Example 1. Also, as mentioned above, it was inferior to Example 1 in terms of glass contamination and glass scratching properties.

[0093] (Example 6) Laminating paper for glass plates was obtained in the same manner as in Example 2, except that 5% of recycled pulp solids was used as the first raw material and 95% of natural virgin pulp solids was used as the second raw material. The resulting laminating paper had a basis weight of 49 g / m². 2 The paper thickness was 75 μm. The fold-back properties of the glass plate laminate in Example 6 were significantly inferior to those of Examples 1 and 2.

[0094] (Example 7) Laminating paper for glass plates was obtained in the same manner as in Example 1, except that 95% of the solid content of recycled pulp was used as the first raw material and 5% of the solid content of natural virgin pulp was used as the second raw material. The resulting laminating paper had a basis weight of 43 g / m². 2 The paper thickness was 64 μm. The glass plate laminate in Example 7 experienced frequent paper breakage during the papermaking process. Furthermore, the glass plate laminate in Example 7 had poor handling characteristics during use.

[0095] (Example 8) Laminating paper for glass plates was obtained in the same manner as in Example 2, except that 95% of the solid content of recycled pulp was used as the first raw material and 5% of the solid content of natural virgin pulp was used as the second raw material. The resulting laminating paper had a basis weight of 44 g / m². 2 The paper thickness was 59 μm. Although NBKP was used as the raw material, the amount of recycled pulp was excessive, resulting in a decrease in paper thickness and Clark stiffness. As a result, handling problems such as the paper peeling and falling out occurred when used as a laminate for glass plates, making satisfactory use impossible.

[0096] (Example 9) A glass plate laminate was obtained in the same manner as in Example 2, except that 45% of the solids were recycled pulp as the first raw material, 45% of the solids were natural virgin pulp as the second raw material, and 10% of the solids were from a deinked pulp (DIP) slurry mainly composed of newspaper waste as the third raw material, and these were mixed together. The resulting laminate had a basis weight of 45 g / m². 2 The paper thickness was 63 μm. The glass plate laminate in Example 9 had relatively good fold-back properties, but due to the high proportion of poor-quality DIP material, it was inferior in terms of glass contamination and glass scratching resistance.

[0097] (Example 10) A deinked pulp (DIP) slurry, mainly composed of newspaper waste, was used as the first raw material, with 50% solid content. Commercial NBKP, used as natural virgin pulp, was beaten in a double disc refiner to produce 550 mL CSF. 50% solid content of this pulp slurry was used as the second raw material. This mixture was then used to produce paper using a long-wire paper machine to obtain laminated paper for glass plates. The resulting laminated paper had a basis weight of 43 g / m². 2 The paper thickness was 62 μm. The glass plate laminate in Example 10 had relatively good fold-back properties, but due to the high proportion of poor-quality DIP material, it was inferior in terms of glass contamination and glass scratching resistance.

[0098] Table 1 shows the evaluation results for each example of glass plate lamination paper. In the table, "Natural virgin pulp L material" means that LBKP was used as the raw material for virgin pulp, and "Recycled pulp L material" means that recycled pulp derived from waste paper of glass plate lamination paper that used LBKP as the raw material was used. "Natural virgin pulp N material" means that NBKP was used as the raw material for virgin pulp, and "Recycled pulp N material" means that recycled pulp derived from waste paper of glass plate lamination paper that used NBKP as the raw material was used.

[0099] [Table 1]

[0100] As explained above, the following matters are disclosed in this specification: 1. A laminate for glass plates containing virgin pulp and recycled pulp, The recycled pulp is derived from recycled paper used for glass plate lamination. The recycled pulp contains 10% by mass or more and 90% by mass or less. Laminating paper for glass plates, having a deinked pulp (DIP) content of 0.1% by mass or less. 2. The Clark stiffness of the glass plate laminate with respect to the papermaking direction is 40 cm 3 The glass plate laminating paper described in item 1 above, wherein the value is less than / 100. 3. The glass plate laminate according to 1 or 2, wherein, in the fiber width distribution of the disintegrated pulp obtained by disintegrating the glass plate laminate, when the median fiber width is Me, the proportion of fibers with a fiber width of (Me-0.5Me) or more and (Me+0.5Me) or less is 70% or more. 4. The glass plate laminate according to any one of 1 to 3 above, wherein the length-weighted average fiber length distribution of the disintegrated pulp obtained by disintegrating the glass plate laminate is divided into the following classes (A) to (F), and the percentage of fibers belonging to each of the classes is expressed as (a) to (f), and at least one of (b)+(c), (c)+(d), and (d)+(e) is 50% or more. (A) Greater than 0mm and less than 0.2mm (B) 0.2 mm or more and less than 0.6 mm (C) 0.6 mm or more and less than 1.2 mm (D) 1.2 mm or more and less than 2.0 mm (E) 2.0 mm or more and less than 3.2 mm (F)3.2mm or more and 7.6mm or less 5. The glass plate laminate according to any one of 1 to 4, wherein the aspect ratio obtained by dividing the Clark stiffness of the glass plate laminate with respect to the papermaking direction by the Clark stiffness in a direction perpendicular to the papermaking direction is 1.80 or more and 2.40 or less. 6. The glass plate interlining is the glass plate interlining described in any one of 1 to 5 above, wherein the concentrations of each element, magnesium, silicon, titanium, iron, and chromium, as measured by X-ray fluorescence analysis, satisfy all of the following conditions (1) to (5). (1) Magnesium 200 ppm or less (2) Silicon 300 ppm or less (3) Titanium 0.10 ppm or less (4) Iron: 0.50 ppm or less (5) Chromium 1.0 ppm or less 7. A glass plate laminate in which multiple glass plates are stacked together, A glass plate laminate having glass plate interleaving paper according to any one of 1 to 6 above between the glass plates. 8. A glass plate packaging body comprising the glass plate laminate described in item 7 above and a pallet on which the glass plate laminate is placed. [Explanation of symbols]

[0101] 1. Laminating paper for glass plates 2 glass plates 10 Glass plate laminate 30 Glass plate packaging 31 Palettes 32 Slope 33 base 34 Mounting platform 50 glass plate packaging 51 Palettes 52 Pillar 53 Base 54 Mounting platform

Claims

1. A laminate for glass plates containing virgin pulp and recycled pulp, The recycled pulp is derived from recycled paper used for glass plate lamination. The recycled pulp contains 10% by mass or more and 90% by mass or less. Laminating paper for glass plates, having a deinked pulp (DIP) content of 0.1% by mass or less.

2. The Clark stiffness of the aforementioned glass plate laminate with respect to the papermaking direction is 40 cm ３ The glass plate laminating paper according to claim 1, wherein the ratio is less than / 100.

3. The glass plate laminate according to claim 1 or 2, wherein, in the fiber width distribution of the disintegrated pulp obtained by disintegrating the glass plate laminate, when the median fiber width is Me, the proportion of fibers with a fiber width of (Me - 0.5Me) or more and (Me + 0.5Me) or less is 70% or more.

4. The glass plate laminate according to claim 1 or 2, wherein the length-weighted average fiber length distribution of the disintegrated pulp obtained by disintegrating the glass plate laminate is divided into the following classes (A) to (F), and the percentage of fibers belonging to each of the classes is expressed as (a) to (f), and at least one of (b) + (c), (c) + (d), and (d) + (e) is 50% or more. (A) Greater than 0 mm and less than 0.2 mm (B) 0.2 mm or more and less than 0.6 mm (C) 0.6 mm or more and less than 1.2 mm (D) 1.2 mm or more and less than 2.0 mm (E) 2.0 mm or more and less than 3.2 mm (F) 3.2 mm or more and 7.6 mm or less

5. The glass plate laminate according to claim 1 or 2, wherein the aspect ratio obtained by dividing the Clark stiffness of the glass plate laminate with respect to the papermaking direction by the Clark stiffness in a direction perpendicular to the papermaking direction is 1.80 or more and 2.40 or less.

6. The glass plate laminate according to claim 1 or 2, wherein the concentrations of each element, magnesium, silicon, titanium, iron, and chromium, as measured by X-ray fluorescence analysis, satisfy all of the following conditions (1) to (5). (1) Magnesium 200 ppm or less (2) Silicon 300 ppm or less (3) Titanium 0.10 ppm or less (4) Iron: 0.50 ppm or less (5) Chromium 1.0 ppm or less

7. A glass plate laminate in which multiple glass plates are stacked together, A glass plate laminate having the glass plate interleaving paper described in claim 1 or 2 between the glass plates.

8. A glass plate packaging body comprising a glass plate laminate as described in claim 7 and a pallet on which the glass plate laminate is placed.

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