glassine paper

Abstract

The utility model provides a kind of glass lining paper, which is a non-woven fabric with a predetermined bending strength. The glass lining paper is a non-woven fabric with a thickness of 60 μm or more and 160 μm or less. For a first test piece cut from the non-woven fabric to 20 mm x 150 mm, the sag length is 70 mm or less when measured by the stiffness measurement method specified in the B method of JIS-L1096-2010, with a protruding length of 100 mm. With this structure, a glass lining paper formed from a non-woven fabric with a predetermined bending strength can be provided that suppresses the thickness of the glass when laminated. This can suppress the generation of particles when the glass lining paper is laminated, and the glass using the glass lining paper can not only maintain cleanliness, but also handle the laminate laminated in a longitudinal orientation.

Description

Technical Field

[0001] This utility model relates to glass liner paper. More specifically, this utility model relates to glass liner paper as a nonwoven fabric. Background Technology

[0002] When conveying flat glass sheets such as architectural glass sheets, automotive glass sheets, and LCD glass sheets, glass backing paper is used to sandwich the glass sheets between each other. In these flat glass sheets, especially those used for LCDs and other flat panel displays, the surface has fine electrical wiring, electrodes, circuits, and spacers. Therefore, even slight damage or contamination can lead to defects such as broken lines. Thus, to avoid damage or contamination, high-quality glass backing paper is required in terms of particle generation. Furthermore, recently, glass backing paper used for automotive glass sheets is sometimes required to have the same quality as that used for flat panel display glass sheets.

[0003] To address the aforementioned issues, patent documents 1 and 2 disclose nonwoven fabrics with a defined structure, namely glass liner paper.

[0004] Furthermore, Patent Document 3 discloses a laminate in which glass plates and glass backing paper are alternately stacked in a longitudinal orientation on a pallet. As the size of flat panel displays increases, the sheet glass used in flat panel displays also increases, and in recent years, glass plates have been transported in a longitudinal orientation during the transport of laminates.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2004-2777991

[0008] Patent Document 2: Japanese Patent Application Publication No. 2009-173510

[0009] Patent Document 3: Japanese Patent Application Publication No. 2022-143331 Utility Model Content

[0010] Technical problem to be solved by the utility model

[0011] However, for the same thickness, the flexural strength of nonwoven fabrics, usually expressed as stiffness, is lower than that of pulp-made paper. Figure 3The diagram shows an explanatory illustration of a laminate 51 formed by alternating vertical stacking of glass plates 52 and glass backing paper 53. An enlarged schematic diagram of the protrusions of the glass backing paper 53 is also shown. When the glass plates 52 are enlarged, i.e., their area increases, vertical stacking is easier than horizontal stacking. Here, when the glass plates 52 are stacked vertically on the conveyor table 50, the glass backing paper 53 sandwiched between the glass plates 52 protrudes approximately 100 mm upwards from the laminate 51. When the glass plates 52 are removed one by one from the laminate 51, the glass backing paper 53 is also removed one by one. However, when the bending strength of the glass backing paper 53 is low, the protrusions of the glass backing paper 53 overlap with the protrusions of adjacent glass backing paper 53, making it impossible to properly insert the holding parts of the glass backing paper 53 between them, and thus impossible to remove the glass backing paper 53 one by one from the laminate 51. Therefore, glass liner paper 53 with low bending strength is difficult to use in longitudinal conveying.

[0012] In view of the above, the purpose of this utility model is to provide a nonwoven fabric, i.e., glass liner, with a predetermined bending strength.

[0013] Technical means to solve the problem

[0014] The glass liner of the first aspect of this utility model is characterized in that the glass liner is a nonwoven fabric with a thickness of 60μm or more and 160μm or less, and for a first test piece of nonwoven fabric cut into 20mm×150mm pieces, the droop length measured by the stiffness measurement method specified in Method B of JIS-L1096-2010 is 70mm or less when the protrusion length is 100mm.

[0015] According to the glass liner paper of the first and second aspects of the present invention, the diameter of the fibers constituting the nonwoven fabric is 20 μm or more.

[0016] According to the first or second aspect of the present invention, the glass liner is characterized in that, for a second test piece of nonwoven fabric cut into 295mm×208mm pieces and not subjected to washing treatment, when measured using the tumbling method of JIS-B9923-1997, the number of particles that can be separated per second is less than 10 for particles larger than 0.3μm and smaller than 0.5μm, less than 20 for particles larger than 0.5μm and smaller than 1.0μm, and less than 20 for particles larger than 1.0μm and smaller than 5.0μm.

[0017] Effects of the utility model

[0018] According to a first aspect of this invention, a glass backing paper formed of a nonwoven fabric with a predetermined bending strength of 70 mm or less at a specified thickness can be provided to suppress the thickness during glass lamination. This suppresses the generation of particles during glass backing paper lamination, and the glass using the glass backing paper not only remains clean but also allows for operation of laminates stacked in a longitudinal orientation.

[0019] According to a second aspect of the present invention, by having the diameter of the fibers constituting the nonwoven fabric be 20 μm or more, it is possible to further improve the bending strength while maintaining the thickness of the nonwoven fabric at a relatively thin state.

[0020] According to a third aspect of the present invention, by reducing the number of particles in the nonwoven fabric to a predetermined number or less, the glass can be kept cleaner when the nonwoven fabric is used as glass backing paper. Attached Figure Description

[0021] Figure 1 This is an illustrative diagram illustrating the method for measuring the bending strength of nonwoven fabrics.

[0022] Figure 2 This is an explanatory diagram showing the measurement positions when measuring the thickness of nonwoven fabric.

[0023] Figure 3 It is an explanatory diagram of a laminated body made of glass plates and glass backing paper stacked alternately in a longitudinal posture, and an enlarged schematic diagram of the protrusions of the glass backing paper. Detailed Implementation

[0024] Next, embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments described below are merely examples of glass liner paper embodying the technical concept of the present invention, and the present invention does not limit the glass liner paper to the following methods. It should be noted that, unless otherwise specified, the dimensions, materials, shapes, etc., of the structural components described in the embodiments are not intended to limit the scope of the present invention, but are merely illustrative examples. Furthermore, for clarity, the size or positional relationships of the components shown in the accompanying drawings may sometimes be exaggerated.

[0025] The glass liner of this invention is a nonwoven fabric with a thickness of 60μm or more and 160μm or less. For a first test piece 20 cut into 20mm × 150mm pieces, the sag length measured using the stiffness measurement method specified in Method B of JIS-L1096-2010, with a protrusion length of 100mm, is 70mm or less. In JIS-L1096-2010, several stiffness measurement methods are described in section 8.21, starting from page 41. For example, Method A for stiffness measurement is described in ISO 9073-7:2024, which corresponds to JIS-L1096-2010. In this application, Method B of the stiffness measurement method is used.

[0026] The glass liner has a droop length of less than 70 mm when the thickness is within a specified range, thereby providing thickness suppression during glass lamination. The glass liner is made of nonwoven fabric with a predetermined bending strength. This suppresses particle generation during glass liner lamination, and the glass using the glass liner not only remains clean but also allows for the handling of laminates stacked in a longitudinal orientation.

[0027] Furthermore, the diameter of the fibers constituting the nonwoven fabric is preferably 20 μm or more. By using fibers with a diameter of 20 μm or more, it is possible to further improve the bending strength while maintaining a relatively thin nonwoven fabric.

[0028] Furthermore, for the second test piece of nonwoven fabric cut into 295mm × 208mm pieces and not subjected to washing treatment, when measuring using the tumbling method of JIS-B9923-1997, the preferred number of particles that can be separated per second is: 10 or less for particles 0.3μm or larger and less than 0.5μm, 20 or less for particles 0.5μm or larger and less than 1.0μm, and 20 or less for particles 1.0μm or larger and less than 5.0μm. By keeping the number of particles in the nonwoven fabric below a predetermined number, the glass can be kept cleaner when the nonwoven fabric is used as glass liner. JIS-B9923-1997 is a standard concerning the determination of contaminant particles in cleanroom clothing, and from page 8 onwards, it describes, in six chapters, various measuring devices using light scattering type automatic particle counter methods. In this application, the tumbling method described in (1.2) is used.

[0029] <Implementation Method>

[0030] (Thickness of non-woven fabric)

[0031] Traditional glass fiber backing paper is mostly made of pulp, and its thickness is required to be between 60μm and 160μm. When the thickness of the glass fiber backing paper is less than 60μm, the possibility of the glass sheets coming into contact with each other increases when stacking. Furthermore, when the thickness of the glass fiber backing paper is greater than 160μm, the stacking height becomes excessive when stacking dozens of sheets of glass. Therefore, the required thickness of the nonwoven fabric used as glass fiber backing paper is between 60μm and 160μm.

[0032] The thickness of the nonwoven fabric in this embodiment is tested according to Method A of "Thickness" as specified in JIS-L1913-2010. Additionally, Figure 2 The diagram illustrates the measurement positions when measuring the thickness of nonwoven fabric. Figure 2 A rectangular test piece 30 measuring 150 mm × 100 mm is shown. For example, in test piece 30, as shown, five measurements are taken at different locations to obtain individual thickness measurements. The average of these measurements can be taken as the thickness of test piece 30, i.e., the thickness of its nonwoven fabric. This is because the thickness of the nonwoven fabric varies depending on the measurement location. JIS-L1913-2010 describes several thickness testing methods in six sections, starting from page 3. For example, ISO 9073-2:1995, corresponding to JIS-L1913-2010, describes method B for thickness measurement. In this application, method A from the thickness measurement methods is used.

[0033] (Flexural strength of nonwoven fabric)

[0034] Figure 1 This is an explanatory diagram illustrating the method for measuring the bending strength of nonwoven fabric used as glass backing paper. Figure 1 A front view of the testing machine 10 is shown. It should be noted that this testing machine 10 is an example of the testing machine specified in Method B of JIS-L1096-2010. The thickness of the nonwoven fabric is determined according to JIS-L1913-2010, "General Test Methods for Nonwoven Fabrics," while the bending strength of the nonwoven fabric used as glass backing is determined according to Method B of JIS-L1096-2010, "Test Methods for Fabrics and Knitted Fabrics." Sometimes, the glass backing is used to tightly bond the glass to the glass using static electricity. In this case, a material that easily generates static electricity is used as the glass backing. As a result, the first test piece 20 easily generates static electricity because the bending strength cannot be measured more accurately using the method specified in JIS-L1913-2010, "General Test Methods for Nonwoven Fabrics."

[0035] The testing machine 10 has a structure in which a columnar column 12 is erected on a flat base 11. A movable stage 13 is positioned relative to the column 12, moving up and down along its side. The base 11 is adjusted so that the upper surface of the movable stage 13 is horizontal. The movable stage 13 is fixed relative to the column 12 by a knob 15 located opposite the side of the column 12 where the movable stage 13 is mounted. A scale 14 is provided on the column 12 to indicate the distance between the movable stage 13 and the apex of the column 12.

[0036] The user of the testing machine 10 cuts the nonwoven fabric to be measured into 20mm × 150mm pieces, preparing the first test piece 20 as the measurement object. Preferably, the length direction of the first test piece 20 is consistent with the overall length direction of the nonwoven fabric, that is, consistent with the direction perpendicular to the width direction of the entire nonwoven fabric. For example... Figure 3 As shown, when forming the laminate 50, it is mostly supplied from the top direction of the laminate 50, and preferably the vertical direction of the protrusion of the glass backing paper 53 is consistent with the length direction of the first test piece 20.

[0037] The user of the testing machine 10 loosens knob 15 and moves the upper surface of the moving stage 13 to a position aligned with the upper surface of the column 12. In this state, knob 15 is tightened to fix the moving stage 13. Next, the user places the first test piece 20 on the upper surface of the column 12. The user places the first test piece 20 with a protruding length W, i.e., the length protruding towards the moving stage 13, for example, 100 mm, so that it only protrudes by a predetermined length. Then, a weight 16 is placed at the end of the column 12 to fix the first test piece 20. The weight 16 is preferably placed with a slight protrusion towards the moving stage 13. Then, the user loosens knob 15 to move the moving stage 13 downwards. Then, the user fixes the moving stage 13 to the column 12 at the height of the free end of the first test piece 20 relative to the moving stage 13 using knob 15, and measures the drooping length b.

[0038] In the glass liner of this embodiment, for the first test piece 20 cut into 20mm × 150mm pieces of nonwoven fabric, the sag length measured by the stiffness measurement method specified in Method B of JIS-L1096-2010, with a protrusion length of 100mm, is 70mm or less. A small sag length means a large bending strength value, and a large sag length means a small bending strength value. Although a sag length of 0mm is preferred, it is unlikely to be 0mm as long as the nonwoven fabric has weight. However, if the sag length is 30mm or less, it is preferable that the holding member for holding the glass liner can be accurately positioned between the glass liners. If the sag length is greater than 70mm, in the case of a laminate of glass formed in a longitudinal orientation, the glass liners overlap each other, and there is a problem that the holding member for removing the glass liner is difficult to feed between the glass liners.

[0039] The glass backing paper has a droop length of 70 mm or less when the thickness is below a specified limit, thereby providing a thickness that can suppress the glass during lamination. It is made of nonwoven fabric with a predetermined bending strength. This can suppress the generation of particles during glass backing paper lamination, and the glass using glass backing paper can not only remain clean, but also be operated in a longitudinally stacked manner.

[0040] (The material of non-woven fabric)

[0041] The material of the nonwoven fabric used as the glass liner in this embodiment is not particularly limited. For example, aramid fibers, glass fibers, cellulose fibers, nylon fibers, vinylon fibers, polyester fibers, polyethylene fibers, polypropylene fibers, polyolefin fibers, rayon fibers, etc., can be used appropriately. In addition, sometimes a combination of these fibers is used. It should be noted that the glass liner in this embodiment is preferably made of polyester fibers stacked together. The stacked continuous fibers are preferably heat-pressed together. By using polyester, a thermoplastic synthetic fiber, as a component of the continuous fibers, glass liner can be produced inexpensively and with high quality. In addition, since polyester fibers have the advantages of excellent strength and moderate hydrophilicity, they are not easily charged in the air and do not easily attract dust from the air.

[0042] The polyester material of the nonwoven fabric used in the glass liner of this embodiment is a condensation polymer of a so-called polycarboxylic acid (dicarboxylic acid) and a polyol (diol). There is no particular limitation as long as it is obtained by dehydration condensation of a polyol (a compound having multiple alcohol functional groups -OH) and a polycarboxylic acid (a compound having multiple carboxylic acid functional groups -COOH). For example, terephthalic acid is preferably used as the polycarboxylic acid (acid component), and polyethylene terephthalate or polybutylene terephthalate obtained from ethylene glycol and butanediol is preferably used as the polyol (diol component). Alternatively, the acid component can be a copolymer of terephthalic acid and other acid components. Additionally, the diol component can be a copolymer of ethylene glycol and other diol components. Examples of other acid components include aromatic dicarboxylic acids such as isophthalic acid, diphenyl ether-4,4′-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, and naphthalene-2,6-dicarboxylic acid; aliphatic dicarboxylic acids such as oxalic acid, succinic acid, adipic acid, sebacic acid, and undecanoic acid; and alicyclic dicarboxylic acids such as hexahydroterephthalic acid. Examples of other glycol components include aliphatic ethylene glycols such as propylene glycol and neopentyl glycol; alicyclic ethylene glycols such as cyclohexanediol; and aromatic dihydroxy compounds such as bisphenol A. As for the polyester, only one polyester can be used, or a mixture formed by blending homopolymers together, or a mixture formed by blending homopolymers and copolymers, can be used.

[0043] In the nonwoven fabric of the glass liner in this embodiment, the preferred polyester is a polyester composed of an aromatic dicarboxylic acid as the acid component and a straight-chain alcohol as the diol component. Examples include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. This is because the above-mentioned polyesters have excellent mechanical strength, as well as excellent heat resistance and flexibility.

[0044] Additives may be appropriately blended into the aforementioned polyester as needed. Examples of additives that can be blended include antistatic agents, colorants, flexibility enhancers, anti-aging agents, heat stabilizers, weathering agents, metal passivators, light stabilizers, antibacterial and antifungal agents, dispersants, softeners, plasticizers, nucleating agents, flame retardants, foaming agents, and foaming aids. However, additives that may leach from the polyester or cause powder or dust to fall off should not be blended.

[0045] The fibers constituting the nonwoven fabric of the glass liner in this embodiment can be single-phase fibers made of a single polyester, or composite fibers made of two or more of the same or different types of polyesters. Furthermore, it is also acceptable to use single-phase fibers made of different polyesters, composite fibers made of combinations of different polyesters, or blends of single-phase fibers and composite fibers.

[0046] (Manufacturing methods and fiber diameter of nonwoven fibers)

[0047] The fibers of the nonwoven fabric used in the glass backing paper of this embodiment are preferably continuous fibers. This is because no fiber shedding occurs. Examples of nonwoven fabrics formed by continuous fiber stacking include spunbond nonwoven fabrics, meltblown nonwoven fabrics, and flash-spun nonwoven fabrics. Considering the advantages of excellent single fiber strength, good dimensional stability of the sheet, reduced contact area with the glass plate due to a relatively small single yarn fineness, and the absence of solvents during manufacturing, spunbond nonwoven fabrics are preferred. Furthermore, the diameter of the fibers constituting the nonwoven fabric is preferably 20 μm or more. For example, when producing continuous fibers for the nonwoven fabric by spunbonding, by setting the orifice diameter of the die used for spunbonding the fibers to 20 μm or more, the fiber diameter can be made to be the same as the orifice diameter of the die, which is 20 μm or more. Additionally, the fiber structure of the nonwoven fabric can be a so-called core-sheath structure. When the fiber structure is a core-sheath structure, the fiber diameter can be easily increased. There is no particular upper limit to the diameter of the fibers constituting the nonwoven fabric, but considering post-manufacturing use, the diameter of the fibers constituting the nonwoven fabric is preferably 40 μm or less.

[0048] By having fibers with a diameter of 20 μm or more in the nonwoven fabric constituting the glass liner of this embodiment, it is possible to further improve the bending strength while maintaining a relatively thin nonwoven fabric thickness.

[0049] (Dust generation from non-woven fabrics)

[0050] In this embodiment, when the nonwoven fabric of the glass liner is cut into 295mm × 208mm pieces and a second test piece is prepared without washing, the following are preferred values ​​for the number of particles that can be separated per second when measured using the tumbling method of JIS-B9923-1997: 10 or fewer particles of 0.3μm or larger and less than 0.5μm, 20 or fewer particles of 0.5μm or larger and less than 1.0μm, and 20 or fewer particles of 1.0μm or larger and less than 5.0μm. JIS-L1913-2010, "General Test Methods for Nonwoven Fabrics," does not specify a method for determining the dust generation of nonwoven fabrics. Therefore, the dust generation of this nonwoven fabric is determined by referring to the measurement method specified in JIS-B9923-1997, "Method for Determination of Contaminating Particles in Garments for Cleanroom Use."

[0051] By keeping the number of particles in the nonwoven fabric below a predetermined amount, the glass can be kept cleaner when the nonwoven fabric is used as glass backing paper.

[0052]

Example

[0053] The specific embodiments of the glass liner paper of this utility model will be described below, but this utility model is not limited to these embodiments.

[0054] (Examples of thickness, basis weight, droop length, and fiber thickness)

[0055] (Example 1)

[0056] A nonwoven fabric was manufactured from polyethylene terephthalate with a continuous fiber core-sheath structure. The thickness of the nonwoven fabric was measured using Test Method A, “Thickness,” as specified in JIS-L1913-2010. A rectangular test piece 30, measuring 150 mm × 100 mm, was used for measurement. Figure 2 As shown, the thickness was measured at five locations, and the average value was taken as the final measurement. The measured thickness was 109.2 μm. Additionally, the basis weight of the nonwoven fabric, i.e., the weight of nonwoven fabric per square meter, was 20 g. Its value is shown in Table 1.

[0057] Next, the nonwoven fabric was cut into strips of 20mm × 150mm, with the length direction aligned with the length of the entire nonwoven fabric, thus preparing the first test piece 20. For this first test piece 20, the droop length was measured twice, with a protrusion length of 100mm, using the stiffness measurement method specified in Method B of JIS-L1096-2010, and the average value was taken as the measurement value. The measured value of the droop length was 52.9mm, confirming that it has sufficient bending strength. The value is shown in Table 1.

[0058] Finally, the fiber thickness of the nonwoven fabric was measured using a digital microscope. Five 20mm × 150mm first test pieces 20 were prepared, and each first test piece 20 was measured twice at a magnification of 200x. The average of a total of 10 measurements was taken as the fiber thickness measurement. The measured fiber thickness was 25.28μm, confirming that it has sufficient thickness. The value is shown in Table 1.

[0059] (Example 2)

[0060] The difference between Example 1 and Example 2 lies in the thickness, basis weight, and fiber thickness after manufacturing. Other manufacturing conditions are the same as in Example 1. Furthermore, the methods for measuring thickness, droop length, and fiber thickness are the same as in Example 1. In Example 2, the measured thickness is 120.8 μm. The basis weight is 25 g. These values ​​are shown in Table 1.

[0061] Furthermore, in Example 2, the measured sag length was 48.5 mm, confirming sufficient bending strength. Additionally, the measured fiber thickness was 29.70 μm, confirming sufficient thickness. These values ​​are shown in Table 1.

[0062] (Comparative Example 1)

[0063] The difference between Example 1 and Comparative Example 1 lies in the thickness, basis weight, and fiber thickness after manufacturing. Additionally, the fiber structure is not a core-sheath structure, but a single fiber structure. Other manufacturing conditions are the same as in Example 1. Furthermore, the methods for measuring thickness, droop length, and fiber thickness are the same as in Example 1. In Comparative Example 1, the measured thickness was 168.9 μm. The basis weight was 35 g. These values ​​are shown in Table 1.

[0064] In Comparative Example 1, the measured sag length was 73.8 mm, confirming low bending strength. In this case, the measured fiber thickness was 14.75 μm, which is insufficient. Furthermore, in Comparative Example 1, the thickness was at least 160 μm (standard value), indicating that the stacking height reached the specified level during lamination. These values ​​are shown in Table 1.

[0065] (Comparative Example 2)

[0066] The difference between Example 1 and Comparative Example 2 lies in the thickness, basis weight, and fiber thickness after manufacturing. Additionally, the fiber structure is not a core-sheath structure, but a single fiber structure. Other manufacturing conditions are the same as in Example 1. Furthermore, the methods for measuring thickness, droop length, and fiber thickness are the same as in Example 1. In Comparative Example 2, the measured thickness was 169.4 μm. The basis weight was 30 g. These values ​​are shown in Table 1.

[0067] In Comparative Example 2, the measured sag length was 73.4 mm, confirming low bending strength. In this case, the measured fiber thickness was 18.41 μm, which is insufficient. Furthermore, in Comparative Example 2, the thickness was at least 160 μm, exceeding the standard value. With this glass backing paper, it is evident that the stacking height during lamination reached the specified level. These values ​​are shown in Table 1.

[0068] (Comparative Example 3)

[0069] The difference between Example 1 and Comparative Example 3 lies in the thickness, basis weight, and fiber thickness after manufacturing. Additionally, the fiber structure is not a core-sheath structure, but a single fiber structure. Other manufacturing conditions are the same as in Example 1. Furthermore, the methods for measuring thickness, droop length, and fiber thickness are the same as in Example 1. In Comparative Example 3, the measured thickness was 181.0 μm. The basis weight was 35 g. These values ​​are shown in Table 1.

[0070] In Comparative Example 3, the measured sag length was 69.1 mm, confirming sufficient bending strength. However, the measured fiber thickness was 17.91 μm, which was insufficient. Furthermore, in Comparative Example 3, the thickness was above the standard value of 160 μm, indicating that the stacking height reached the specified value during lamination. These values ​​are shown in Table 1.

[0071] (Comparative Example 4)

[0072] The difference between Example 1 and Comparative Example 4 lies in the thickness, basis weight, and fiber thickness after manufacturing. Additionally, the fiber structure is not a core-sheath structure, but a single fiber structure. Other manufacturing conditions are the same as in Example 1. Furthermore, the methods for measuring thickness, droop length, and fiber thickness are the same as in Example 1. In Comparative Example 4, the measured thickness was 186.6 μm. The basis weight was 40 g. These values ​​are shown in Table 1.

[0073] In Comparative Example 4, the measured sag length was 63.6 mm, confirming sufficient bending strength. However, the measured fiber thickness was 13.53 μm, which was insufficient. Furthermore, in Comparative Example 4, the thickness was at least 160 μm, exceeding the standard value, indicating that the stacking height during lamination exceeded the specified limit. These values ​​are shown in Table 1.

[0074] (Comparative Example 5)

[0075] The difference between Example 1 and Comparative Example 5 lies in the thickness, basis weight, and fiber thickness after manufacturing. Additionally, the fiber structure is not a core-sheath structure, but a single fiber structure. Other manufacturing conditions are the same as in Example 1. Furthermore, the methods for measuring thickness, droop length, and fiber thickness are the same as in Example 1. In Comparative Example 5, the measured thickness was 192.5 μm. The basis weight was 45 g. These values ​​are shown in Table 1.

[0076] In Comparative Example 5, the measured sag length was 61.0 mm, confirming sufficient bending strength. However, the measured fiber thickness was 12.82 μm, which was insufficient. Furthermore, in Comparative Example 5, the thickness was at least 160 μm, exceeding the standard value, indicating that the stacking height reached the specified level during lamination. These values ​​are shown in Table 1.

[0077] (Comparative Example 6)

[0078] The difference between Example 1 and Comparative Example 6 lies in the thickness, basis weight, and fiber thickness after manufacturing. Additionally, the fiber structure is not a core-sheath structure, but a single fiber structure. Other manufacturing conditions are the same as in Example 1. Furthermore, the methods for measuring thickness, droop length, and fiber thickness are the same as in Example 1. In Comparative Example 6, the measured thickness was 197.1 μm. The basis weight was 45 g. These values ​​are shown in Table 1.

[0079] In Comparative Example 6, the measured sag length was 45.4 mm, confirming sufficient bending strength. However, the measured fiber thickness was 16.37 μm, which was insufficient. Furthermore, in Comparative Example 6, the thickness was at least 160 μm, exceeding the standard value, indicating that the stacking height reached the specified level during lamination. These values ​​are shown in Table 1.

[0080] (Comparative Example 7)

[0081] The difference between Example 1 and Comparative Example 7 lies in the thickness and fiber thickness after manufacturing. Additionally, the fiber structure is not a core-sheath structure, but a separate fiber structure. Other manufacturing conditions are the same as in Example 1. Furthermore, the methods for measuring thickness, droop length, and fiber thickness are the same as in Example 1. In Comparative Example 7, the measured thickness was 117.7 μm. The basis weight was 20 g. These values ​​are shown in Table 1.

[0082] In Comparative Example 7, the thickness was below the standard value of 160 μm, which is quite thin. However, the measured sag length was 100.9 mm, confirming low bending strength. Furthermore, the measured fiber thickness was 14.34 μm, which is insufficient. These values ​​are shown in Table 1.

[0083] (Comparative Example 8)

[0084] The difference between Example 1 and Comparative Example 8 lies in the thickness, basis weight, and fiber thickness after manufacturing. Additionally, the fiber structure is not a core-sheath structure, but a single fiber structure. Other manufacturing conditions are the same as in Example 1. Furthermore, the methods for measuring thickness, droop length, and fiber thickness are the same as in Example 1. In Comparative Example 8, the measured thickness was 129.8 μm. The basis weight was 25 g. These values ​​are shown in Table 1.

[0085] In Comparative Example 8, the thickness was below the standard value of 160 μm, which is quite thin. However, the measured sag length was 91.2 mm, confirming low bending strength. Furthermore, the measured fiber thickness was 15.60 μm, which is insufficient. These values ​​are shown in Table 1.

[0086] (Comparative Example 9)

[0087] The difference between Example 1 and Comparative Example 9 lies in the thickness, basis weight, and fiber thickness after manufacturing. Additionally, the fiber structure is not a core-sheath structure, but a single fiber structure. Other manufacturing conditions are the same as in Example 1. Furthermore, the methods for measuring thickness, droop length, and fiber thickness are the same as in Example 1. In Comparative Example 9, the measured thickness was 156.3 μm. The basis weight was 30 g. These values ​​are shown in Table 1.

[0088] In Comparative Example 9, the thickness was below the standard value of 160 μm, which is quite thin. However, the measured sag length was 86.2 mm, confirming low bending strength. Furthermore, the measured fiber thickness was 13.09 μm, which is insufficient. These values ​​are shown in Table 1.

[0089] (Refer to Example 1)

[0090] The difference between Example 1 and Reference Example 1 is that Example 1 is a nonwoven fabric, while Reference Example 1 is paper made from pulp. That is, the concept of fiber thickness is not present in Reference Example 1. Furthermore, Example 1 differs from Reference Example 1 in the thickness and basis weight after manufacturing. However, the methods for measuring thickness, droop length, and fiber thickness are the same as in Example 1. In Reference Example 1, the measured thickness is 83.2 μm. The basis weight is 50 g. These values ​​are shown in Table 1.

[0091] In Reference Example 1, the measured sag length was 41.3 mm, confirming sufficient bending strength. The values ​​are shown in Table 1.

[0092] (Table 1)

[0093]

[0094] Glass liner sheets were prepared for both the examples and comparative examples, and the orientation of adjacent glass liner sheets after stacking was visually assessed. The results showed that in the glass liner sheets of Examples 1 and 2, sufficient space was available between adjacent glass liner sheets, and the clamping member of the glass liner sheet could be easily inserted between them. In contrast, for the glass liner sheets of Comparative Examples 1-6, the thickness of the glass liner sheet and the thickness of the stacked body were increased. Furthermore, in Comparative Examples 7-9, the glass liner sheets were tightly fitted together, and sometimes the clamping member of the glass liner sheet could not be inserted between adjacent glass liner sheets.

[0095] (Example regarding dust generation from nonwoven fabrics)

[0096] For Example 1 and Comparative Example 1, a second test piece was prepared and measured regarding the dust emission amount of the nonwoven fabric. The dust emission amount was determined by using the tumbling method specified in JIS-B9923-1997 "Method for determination of contaminating particles in clothing for cleanroom use".

[0097] (Example 1)

[0098] A second test piece of nonwoven fabric measuring 295 mm × 208 mm was prepared as the sample size. This sample was not washed. The amount of dust generated by this second sample was determined using a tumbling dust generation tester CW-HDT-102 manufactured by Akado Seisakusho Co., Ltd. The test apparatus had a drum speed of 30 RPM, a flow rate of 0.0102 m³ / s, an intake rate of 1 cubic foot / min, and a particle counter of Met One A2400B from Hach Ultra Analytics. The measurement results show that the number of particles that can be separated per second is: 1.3 for particles larger than 0.3 μm and smaller than 0.5 μm, 3.7 for particles larger than 0.5 μm and smaller than 1.0 μm, and 2.0 for particles larger than 1.0 μm and smaller than 5.0 μm. For paper made from pulp, the standard particle count is: 10 for particles larger than 0.3 μm and smaller than 0.5 μm, 20 for particles larger than 0.5 μm and smaller than 1.0 μm, and less than 20 for particles larger than 1.0 μm and smaller than 5.0 μm. These values ​​are shown in Table 2.

[0099] (Comparative Example 1)

[0100] The difference between Example 1 and Comparative Example 1 lies in the thickness, basis weight, and fiber coarseness after manufacturing. Additionally, the fiber structure is not a core-sheath structure, but a single fiber structure. Other manufacturing conditions are the same as in Example 1. Furthermore, the method for measuring dust generation is the same as in Example 1. The measurement results show that the number of separable particles per second is: 13.8 for particles 0.3 μm or larger and smaller than 0.5 μm, 22.3 for particles 0.5 μm or larger and smaller than 1.0 μm, and 28.5 for particles 1.0 μm or larger and smaller than 5.0 μm. All of these exceed the standard values ​​for paper made from pulp. These values ​​are shown in Table 2.

[0101] (Table 2)

[0102]

[0103] Explanation of reference numerals in the attached figures

[0104] 10: Testing machine, 11: Base, 12: Column, 13: Moving table, 14: Scale, 15: Knob, 16: Weight, 20: Test piece, b: Droop length, W: Protrusion length.

Claims

1. A glass lining paper which is a nonwoven fabric having a thickness of 60 μm or more and 160 μm or less, characterized in that, for a first test piece cut from the nonwoven fabric to 20 mm x 150 mm, a sag length of 70 mm or less is measured by a stiffness measurement method prescribed in the B method of JIS-L1096-2010, in a case where a protruding length is 100 mm.

2. The glass lining paper according to claim 1, characterized in that, a diameter of a fiber constituting the nonwoven fabric is 20 μm or more.

3. The glass lining paper according to claim 1 or 2, characterized in that, for a second test piece cut from the nonwoven fabric to 295 mm x 208 mm and not subjected to a washing treatment, when measured using a tumbling method of JIS-B9923-1997, for a number of particles of 0.3 μm or more and less than 0.5 μm, the number of particles is 10 or less, for a number of particles of 0.5 μm or more and less than 1.0 μm, the number of particles is 20 or less, and for a number of particles of 1.0 μm or more and less than 5.0 μm, the number of particles is 20 or less.

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