Method for manufacturing glass cloth

Abstract

To provide a method for manufacturing glass cloth, which includes detecting the degree of air permeability in real time during the continuous production of glass cloth. [Solution] A method for manufacturing glass cloth, comprising weaving glass yarn to obtain glass cloth and transporting the glass cloth, wherein, during the transport of the glass cloth, the total area of ​​basket holes per predetermined area of ​​the glass cloth is measured, and the air permeability of the glass cloth is estimated from the obtained total area of ​​basket holes per predetermined area of ​​the glass cloth.

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing glass cloth. [Background technology]

[0002] In recent years, with the increasing sophistication of electronic devices, there has been a remarkable progress in increasing the density and thinning of printed circuit boards used in them.

[0003] As an insulating material for printed circuit boards, laminates are widely used that are made by laminating prepregs, obtained by impregnating glass cloth with a thermosetting resin (matrix resin) such as epoxy resin, and then curing them under heat and pressure. In this case, if there are variations in the performance and quality of the glass cloth, then variations will also occur in the properties of the prepreg containing it, such as resin content, heat resistance, copper foil peel strength, dimensional stability, and substrate warpage, which in turn will lead to variations in the performance of the resulting printed circuit board. Therefore, glass cloth is required to have stable and uniform properties.

[0004] In particular, the breathability of the glass cloth is an important parameter that determines the performance of the printed circuit board, and variations in breathability can lead to problems such as the following: When manufacturing prepregs by impregnating glass cloth with thermosetting resin, variations in the amount of resin can lead to uneven thickness of printed circuit boards; When manufacturing prepregs by impregnating glass cloth with thermosetting resin, variations in the wettability of the glass cloth result in an uneven distribution of the resin, causing warping in the printed circuit board; The uneven distribution of glass particles within the glass cloth causes a propagation delay time difference (skew) between a pair of differential transmission wirings; The occurrence of pinholes during the manufacturing of prepregs by impregnating glass cloth with thermosetting resin, which impairs the electrical performance of printed circuit boards; etc.

[0005] Therefore, controlling the degree of air permeability is extremely important when manufacturing glass cloth. In this regard, Patent Document 1 describes how to equalize properties such as air permeability by controlling the difference in warp thread width between the widthwise edges and the widthwise center of the glass cloth so that it is less than or equal to the standard deviation of the warp thread width. Furthermore, Patent Document 2 describes cutting the manufactured glass cloth into a sample of a predetermined size, and evaluating its properties such as air permeability at a total of 60 locations, with 20 locations at equal intervals in the width direction and three rows of these locations in the length direction. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2024-048028 [Patent Document 2] Japanese Patent Publication No. 2023-125119 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, Patent Document 1 merely explains that the standard deviation of warp thread width can be reduced by adjusting the tension during warping, the pressure of the high-pressure water spray during fiber opening, and the line tension during fiber opening processing, thereby indirectly making the breathability more uniform. Patent Document 2, on the other hand, concerns a method for evaluating glass cloth after manufacturing. Therefore, none of these patent documents relate to a technique for detecting products that are below specification in terms of air permeability during the manufacturing of glass cloth produced in continuous production. Furthermore, since measuring air permeability in accordance with JIS standards is a destructive test, it is considered essentially impossible to measure air permeability during the manufacturing of glass cloth, which is produced in continuous production.

[0008] This invention was made in view of the above circumstances. An object of the present invention is to provide a method for manufacturing a glass cloth, which includes detecting the air permeability in real time during continuous production of the glass cloth.

Means for Solving the Problems

[0009] The present invention is summarized as follows.

[0010] <<Aspect 1>> A method for manufacturing a glass cloth, including weaving glass yarns to obtain a glass cloth and conveying the glass cloth, wherein during the conveyance of the glass cloth, the total area of the basket holes per predetermined area of the glass cloth is measured, and the air permeability of the glass cloth is estimated from the total area of the basket holes per predetermined area of the obtained glass cloth. A method for manufacturing a glass cloth. <<Aspect 2>> The method for manufacturing a glass cloth according to Aspect 1, wherein the measurement of the total area of the basket holes per predetermined area of the glass cloth is performed by photographing the glass cloth with a camera arranged opposite to a light source through the glass cloth and image analysis of the photographed image. <<Aspect 3>> The method for manufacturing a glass cloth according to Aspect 1, wherein the estimation of the air permeability of the glass cloth from the total area of the basket holes per predetermined area of the glass cloth is performed using a calibration curve prepared in advance using the total area of the basket holes per predetermined area measured for a plurality of glass cloths having the same weave structure (style) as the glass cloth and the actually measured value of the air permeability measured for the glass cloth in accordance with JIS R3420:2023. <<Aspect 4>> The method for manufacturing a glass cloth according to Aspect 1, wherein the estimation of the air permeability of the glass cloth from the total area of the basket holes per predetermined area of the glass cloth is ​​​​Regarding a plurality of glass cloths having the same weaving structure (style) as the glass cloth, the total area of the basket holes per predetermined area measured for the glass cloth, and the measured actual air permeability value of the glass cloth measured in accordance with JIS R3420:2023 for the glass cloth using a calibration curve prepared in advance, The method for manufacturing the glass cloth according to Embodiment 2. <<Embodiment 5>> The method for manufacturing the glass cloth according to any one of Embodiments 1 to 4, wherein the measurement of the total area of the basket holes per predetermined area of the glass cloth and the estimation of the air permeability of the glass cloth are continuously performed in the conveying direction of the glass cloth. <<Embodiment 6>> The method for manufacturing the glass cloth according to any one of Embodiments 1 to 4, including winding the glass cloth after conveyance into a roll shape. <<Embodiment 7>> The method for manufacturing the glass cloth according to Embodiment 6, wherein the total length of the glass cloth wound into a roll shape is 200 m or more and 5,000 m or less. <<Embodiment 8>> The method for manufacturing the glass cloth according to Embodiment 6, wherein the measurement of the total area of the basket holes per predetermined area of the glass cloth and the estimation of the air permeability of the glass cloth are continuously performed in the conveying direction (MD direction) of the glass cloth. <<Embodiment 9>> A tolerance range is set for the air permeability of the glass cloth, and when the glass cloth has a region showing an air permeability outside the set tolerance range, excluding the region showing an air permeability outside the set tolerance range from the glass cloth. The method for manufacturing the glass cloth according to any one of Embodiments 1 to 4. <<Embodiment 10>> The method for manufacturing the glass cloth according to any one of Embodiments 1 to 4, wherein the dielectric constant of the glass cloth at 10 GHz is 5.0 or less.

Advantages of the Invention

[0011] A method for manufacturing glass cloth is provided, which includes detecting, in real time, products that are out of specification, particularly in terms of air permeability, during the continuous production of glass cloth. [Modes for carrying out the invention]

[0012] The method for manufacturing glass cloth in this embodiment is: A method for manufacturing glass cloth, comprising weaving glass yarn to obtain glass cloth (weaving process) and transporting the glass cloth (transportation process), During the transport of the aforementioned glass cloth, The total area of ​​basket holes per predetermined area of ​​the glass cloth is measured. The degree of air permeability of the glass cloth is estimated from the total area of ​​basket holes per predetermined area of ​​the obtained glass cloth. This is a method for manufacturing glass cloth.

[0013] In this specification, "basket hole" refers to the space between the warp and weft threads when viewing the glass cloth from the thickness direction, and is a part where no glass threads are present. The inventors have found that the air permeability of a prepreg correlates with the total area of ​​basket holes per unit area of ​​glass cloth, provided that the weave structure (style) is the same. In this embodiment, by utilizing the relationship between the degree of air permeability and the total area of ​​the basket holes, it is possible to detect the degree of air permeability of the glass cloth in real time, preferably continuously, during the conveying process.

[0014] The method for manufacturing glass cloth in this embodiment includes a weaving process and a conveying process, as described above. The method for manufacturing glass cloth according to this embodiment may include a processing step selected from at least one of the following, either before or after the weaving process: removing sizing agents adhering to the glass yarn (de-oiling step), covering the surface of the glass yarn with a silane coupling agent (surface treatment step), and after the weaving process, it may include a fiber opening step for the glass cloth. Preferably, the process involves a de-oiling step after the weaving step, followed by a surface treatment step and a fiber opening step in any order, and then a conveying step. The fiber opening step may be performed before or after the surface treatment step, or simultaneously with the surface treatment step.

[0015] First, a glass cloth to which the glass cloth manufacturing method of this embodiment is preferably applied will be described, followed by a description of each step constituting the glass cloth manufacturing method of this embodiment.

[0016] Glass cloth The glass cloth of this embodiment is woven using glass yarn containing multiple glass filaments as the warp and weft threads. Examples of weaving methods for the glass cloth include plain weave, twill weave, satin weave, and twill weave, with plain weave being preferred. The average filament diameter of the glass filaments constituting the glass thread is preferably 3.0 μm or more and 9.0 μm or less, more preferably 3.0 μm or more and 7.5 μm or less, and even more preferably 3.5 μm or more and 7.0 μm or less. The average number of monoglass filaments constituting the warp and weft threads is preferably 20 to 250, more preferably 30 to 230, and even more preferably 33 to 220, respectively.

[0017] The weft and warp thread density of the glass cloth in this embodiment is preferably 30 to 120 threads / 25 mm (= 30 to 120 threads / inch), and more preferably 40 to 100 threads / 25 mm, respectively. If the weft density is within the above range, it is easy to obtain a glass cloth of a suitable thickness for use on printed circuit boards. The weft and warp thread density may be the same or different. The thickness of the glass cloth is preferably 120 μm or less, more preferably 100 μm or less. In particular, when emphasizing the miniaturization of electronic devices manufactured using the glass cloth, the thickness of the glass cloth may be 80 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, or 20 μm or less. The thickness of the glass cloth is preferably 5 μm or more, more preferably 10 μm or more. In particular, when emphasizing the reduction of warping of electronic devices manufactured using the glass cloth, the thickness of the glass cloth may be 20 μm or more, 50 μm or more, or 80 μm or more. If the thickness of the glass cloth is within the above range, it is easy to obtain a glass cloth suitable as an insulating material in a printed circuit board.

[0018] The air permeability of the glass cloth measured in accordance with JIS R3420:2023 is, from the viewpoint of ensuring good resin impregnation properties, more than 0 cm 3 / (cm 2 · second), 5 cm 3 / (cm 2 · second) or more, or 10 cm 3 / (cm 2 · second) or more, and from the viewpoint of reducing pinholes and skew, 250 cm 3 / (cm 2 · second) or less, 220 cm 3 / (cm 2 · second) or less, or 200 cm 3 / (cm 2 · second) or less.

[0019] In the present embodiment, as the material of the glass fibers (glass filaments) constituting the glass cloth, glass generally used for printed wiring board applications may be used. Specifically, for example, E glass (alkali-free glass); low dielectric constant glasses such as D glass, L glass, NE glass, L2 glass, silica glass, and quartz glass; high-strength glasses such as S glass and T glass; high dielectric constant glasses such as H glass; etc. can be used. The glass fibers may be composed of one type of glass material, or may be a combination of two or more types of glass fibers composed of different glass materials.

[0020] The dielectric constant of the glass cloth in this embodiment is preferably 5.0 or less, more preferably 4.9 or less, even more preferably 4.8 or less, and particularly preferably 4.6 or less at a frequency of 10 GHz. The dielectric constant can be measured, for example, by the cavity resonance method. In this embodiment, unless otherwise specified, the dielectric constant refers to the dielectric constant at a frequency of 10 GHz.

[0021] In this embodiment, the width of the glass cloth (in the TD direction) is preferably 1,000 mm or more and 1,500 mm or less. Furthermore, as will be described later, when winding the glass cloth onto a roll after manufacturing, the total length of the glass cloth (in the MD direction) is preferably between 200m and 5,000m.

[0022] 《Weaving process》 In the weaving process, glass yarn is woven to obtain glass cloth. Here, the glass cloth is woven by weaving the weft threads into the warp threads using a suitable loom, so that the resulting glass cloth has the desired weave structure (style). In one embodiment, warp threads arranged horizontally in parallel are opened at the top and bottom using an air jet loom system, and weft threads supplied from a weft storage device are fed out by a jet stream from a nozzle and inserted into the openings at the top and bottom of the warp threads to perform weaving. In another embodiment, a water jet loom system or a shuttle system is used instead of the air jet loom system. The weaving process may include a glass yarn ejection process in which the glass yarn to be used as the weft is unwound from a bobbin and ejected through a weft yarn storage device. In the glass yarn ejection process, the weft yarn is transported while interfering with loom components such as yarn guides, for example, as follows: Conveying that involves movement in a direction different from the direction of weft movement (such as ballooning motion), or Conveying involves fluctuations in tension due to the repeated ejection and stopping of the weft thread in units of one weft thread length.

[0023] 《Deoiling process》 In the de-oiling process, sizing agents adhering to the glass fibers of the glass cloth are removed. Sizing agents are used to protect glass yarn, particularly in the weaving process. Glass yarn to which a sizing agent is applied reduces problems such as yarn breakage during the weaving process. Examples of such sizing agents include starch-based binders and polyvinyl alcohol-based binders. Starch-based binders contain at least starch, and polyvinyl alcohol-based binders contain at least polyvinyl alcohol. They may also be mixtures of starch or polyvinyl alcohol with waxes, respectively.

[0024] The method of degreasing may be, for example, heat removal (heat cleaning). The temperature used for heat removal is preferably 300°C to 550°C, more preferably 350°C to 480°C, and even more preferably 370°C to 450°C, from the viewpoint of sufficiently removing the sizing agent while maintaining the breaking strength of the glass yarn. The heating time used for heat removal may be appropriately adjusted by those skilled in the art depending on conditions such as the heating temperature and the thickness of the glass cloth. The heating time used for heat removal is preferably 20 hours to 80 hours, more preferably 25 hours to 70 hours, and even more preferably 30 hours to 60 hours, from the viewpoint of sufficiently removing the sizing agent while maintaining the breaking strength.

[0025] In the de-oiling process, the glass cloth may be washed with water at least before and after the heat removal. Washing with water before heat removal can remove a portion of the sizing agent. Washing with water after heat removal can remove the combustion residue of the sizing agent adhering to the surface of the glass fibers that make up the glass cloth.

[0026] Surface treatment process In the surface treatment process, the surface of the glass fibers that make up the glass cloth is covered with a silane coupling agent. This improves the reactivity between the glass cloth and the matrix resin when manufacturing the prepreg from the glass cloth. The surface treatment process may be carried out, for example, by contacting the glass cloth with a surface treatment agent consisting of a solution containing a silane coupling agent at a concentration of 0.1% by mass or more and 3.0% by mass or less, followed by drying. Methods for bringing the glass cloth into contact with the surface treatment agent include, for example, immersion methods and coating methods. The coating method may be carried out using, for example, a roll coater, die coater, or gravure coater. To dry the glass cloth after contact with the surface treatment agent, methods such as hot air drying or electromagnetic wave heating can be used.

[0027] Examples of silane coupling agents included in surface treatment agents include N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropylmethyldimethoxysilane, N-β-(N-di(vinylbenzyl)aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(N-di(vinylbenzyl)aminoethyl)-N-γ-(N-vinylbenzyl)-γ-aminopropyltrimethoxysilane, etc., and their hydrochloride salts; as well as N-vinyltrimethoxysilane, methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, etc., and one or more selected from these may be used. The solvent contained in the surface treatment agent may be water or an organic solvent, but from the viewpoint of safety and environmental protection, water or a mixed solvent of water and a water-soluble organic solvent is preferred, and water is more preferred. The surface treatment agent may further contain a dispersant to improve the dispersibility and stability of the silane coupling agent.

[0028] 《Opening process》 Glass cloth's glass threads are in a state where multiple glass filaments are bundled together in a cylindrical shape, resulting in a round cross-section. In the fiber opening process, the multiple glass filaments that make up the glass yarn are opened into a wide, thin cross-section yarn, reducing the number of filaments in the thickness direction of the glass cloth. Performing this fiber opening process allows for quick and uniform impregnation of the matrix resin into the glass cloth when manufacturing the prepreg from the glass cloth.

[0029] The fiber opening process involves applying physical force to the glass cloth to separate the multiple glass filaments that make up the glass thread. Examples of physical forces used for fiber separation include water flow, high-pressure airflow, dry ice blasting, high-frequency vibration, ultrasonic vibration, and pressurization by a roll. The medium used when applying high-frequency vibration and ultrasonic vibration may be, for example, degassed water, ion-exchanged water, deionized water, electrolyzed cationized water, electrolyzed anionized water, etc.

[0030] The fiber opening process may be performed before or after the surface treatment process, or it may be performed simultaneously with the surface treatment process. When water or the like is used to apply physical force, the glass cloth after the fiber opening process may be appropriately heated and dried.

[0031] 《Conveying Process》 In the conveying process, the glass cloth after the weaving process (preferably after the weaving process, de-oiling process, surface treatment process, and fiber opening process) is moved using a roll-to-roll method. In other words, the glass cloth, which has been wound into a roll on the source roll after passing through the weaving process (preferably the weaving process, de-oiling process, surface treatment process, and fiber opening process), is unwound and then wound into a roll again on the destination roll, thereby carrying it to the destination. Therefore, the glass cloth is wound into a roll after transport.

[0032] In the glass cloth manufacturing method of this embodiment, during the conveying process, The total area of ​​basket holes per predetermined area of ​​glass cloth is measured. The air permeability of the glass cloth is estimated from the total area of ​​basket holes per predetermined area of ​​the obtained glass cloth. The measurement of the total area of ​​basket holes per predetermined area of ​​glass cloth is preferably performed by continuously photographing the portion of the glass cloth being transported, from the time it is unwound from the source roll until it is wound onto the destination roll, using a camera, and then performing image analysis. Here, "continuously photographing the glass cloth during transport" means taking at least three photographs for the entire length of the glass cloth without any seams. A higher number of photographs per length of the glass cloth is preferable. Specifically, it is preferable to take at least 0.1 photographs per meter of glass cloth, and more preferably 1 or more. There is no particular upper limit to the number of photographs per meter of glass cloth, but 10 or fewer is sufficient.

[0033] The camera used for shooting should preferably have a high pixel resolution. Specifically, a pixel resolution of 0.1 mm / pix or less is desirable. Examples of cameras with such high pixel resolution include cameras equipped with contact image sensors, area sensors, etc.

[0034] It is preferable to photograph the glass cloth using a camera positioned opposite the light source through the glass cloth. That is, during the transport of the glass cloth, the camera, glass cloth, and light source are arranged in this order, and the glass cloth, illuminated by the light source, is photographed by the camera from the side opposite the light source. Here, it is preferable that the line connecting the camera and the light source is perpendicular to the plane of the transported glass cloth. The distance between the camera lens and the glass cloth is preferably set to a range of 5 mm to 50 mm. The distance between the light source and the glass cloth is preferably set to a range of 5 mm to 50 mm.

[0035] By performing image analysis on the images of the glass cloth taken in the manner described above, the total area of ​​basket holes per predetermined area of ​​the glass cloth can be obtained. Image analysis of captured images of glass cloth may be performed, for example, by the following logic. When the light source is visible light, in a positive image of glass cloth, areas where the irradiated light passes through areas without glass cloth appear white. Therefore, by binarizing the captured image and calculating the ratio of the white area to the image area, the area ratio of basket holes per captured area of ​​glass cloth can be determined, and from this value, the total area of ​​basket holes per predetermined area of ​​glass cloth can be calculated. When calculating the ratio of basket hole area per glass cloth exposure area, the exposure area of ​​the glass cloth is 3,000 mm² per image. 2 Over 100,000 mm 2 The following is preferable.

[0036] Next, the air permeability of the glass cloth is estimated from the total area of ​​basket holes per predetermined area of ​​the glass cloth. Here, it has been found that if the weave structure (style) of the glass cloth is the same, there is a linear correlation between the total area of ​​basket holes per predetermined area of ​​the glass cloth and the value of air permeability according to JIS P3420:2023. Therefore, a calibration curve can be created in advance using the total area of ​​basket holes per predetermined area measured by the above method for glass cloth with the same weave structure (style) as the glass cloth of the measurement plate design, and the measured value of air permeability measured according to JIS R3420:2023 for that glass cloth. Using this calibration curve, the air permeability of the glass cloth can be estimated from the total area of ​​basket holes per predetermined area of ​​the glass cloth.

[0037] The measurement of the total area of ​​basket holes per predetermined area of ​​glass cloth and the estimation of the air permeability of the glass cloth may be performed independently and continuously in one or both of the glass cloth's transport direction (MD direction) and width direction (TD direction). In particular, it is preferable to perform the measurement of the total area of ​​basket holes per predetermined area of ​​glass cloth and the estimation of the glass cloth's air permeability continuously in the glass cloth's transport direction (MD direction).

[0038] Through the above operations, it is possible to determine the distribution of air permeability in the direction of transport (MD direction) of the glass cloth, preferably wound into a roll. By setting an acceptable range for the air permeability of the glass cloth, it is possible to determine whether there is a "spec-out" area in the glass cloth that exceeds the set acceptable range for air permeability, and to identify its location. Therefore, preferably, the air permeability specification out region can be excluded from the glass cloth wound in a roll.

[0039] Even if the method of this embodiment detects that the glass cloth being transported has a specification-out region indicating an air permeability outside the set tolerance range, the transport of the glass cloth may be continued without interruption. If the transported glass cloth is to be wound into a roll, the winding onto the roll may be continued without interruption. Furthermore, during "re-transportation," where the glass cloth that has been wound onto a roll is wound onto, for example, another roll, when the unwound glass cloth reaches the out-of-spec region, the transport can be stopped, and the out-of-spec region can be cut out and removed. After cutting out the specified area, the sections before and after that area can be joined together, for example, with splice tape, and transport can be continued. Alternatively, the sections before and after that area can be left unjoined and treated as separate rolls.

[0040] 《Specific application example》 A glass cloth (L glass cloth, style 3313) with a weft width of 1,300 mm and a total length of 2,000 m was manufactured. During the transport process, the total area of ​​basket holes per predetermined area of ​​the glass cloth was measured, and the air permeability of the glass cloth was estimated from the obtained measurements. The weaving process, de-oiling process, surface treatment process, and fiber opening process were carried out in this order (the surface treatment process and fiber opening process were performed simultaneously), after which the glass cloth was transported and wound into a roll. During this transport process, the area of ​​the basket holes was measured and the degree of ventilation was estimated under the following conditions.

[0041] The following light source and camera were positioned opposite each other across the glass cloth being transported. At this time, the line connecting the light source and the camera was perpendicular to the surface of the glass cloth being transported, and the arrangement was such that the camera, glass cloth, and light source were positioned vertically above. Light source: LED line light source device (manufactured by Rebox Co., Ltd., product name "SPX-TB-80-NN-1680-WHT-S-NP-CLR") Camera: Contact image sensor (CIS) camera (manufactured by Mitsubishi Electric Corporation, product name "KD6R1688CXL-NL")

[0042] While winding the glass cloth at a speed of 30 m / min, a light source was shone from below, and images were taken with a CIS camera 200 times at a frequency of once every 10 m along the entire length of the glass cloth roll. The shooting range per image was 65,000 mm. 2 The dimensions were set to (1,300 mm in the width direction x 50 mm in the transport direction). After all the images were captured, each of the 200 images was binarized, and the white areas were used to represent the basket holes. The total area of ​​the white areas relative to the image (capture range) was calculated, and the degree of ventilation was determined.

Claims

1. A method for manufacturing glass cloth, comprising weaving glass yarn to obtain glass cloth and transporting the glass cloth, During the transport of the aforementioned glass cloth, The total area of ​​basket holes per predetermined area of ​​the glass cloth is measured. The degree of air permeability of the glass cloth is estimated from the total area of ​​basket holes per predetermined area of ​​the obtained glass cloth. A method for manufacturing glass cloth.

2. The measurement of the total area of ​​basket holes per predetermined area of ​​the glass cloth is The glass cloth is photographed by a camera positioned opposite the light source via the glass cloth, and Image analysis of captured images A method for manufacturing glass cloth according to claim 1, carried out by the method described above.

3. The estimation of the air permeability of the glass cloth is based on the total area of ​​basket holes per predetermined area of ​​the glass cloth. Regarding multiple glass cloths having the same weave structure (style) as the aforementioned glass cloth, The total area of ​​basket holes per predetermined area measured for the glass cloth, The measured values ​​of the air permeability of the glass cloth in accordance with JIS R3420:2023 and This is performed using a calibration curve that has been prepared in advance. A method for manufacturing glass cloth according to claim 1.

4. The estimation of the air permeability of the glass cloth is based on the total area of ​​basket holes per predetermined area of ​​the glass cloth. Regarding multiple glass cloths having the same weave structure (style) as the aforementioned glass cloth, The total area of ​​basket holes per predetermined area measured for the glass cloth, The measured values ​​of the air permeability of the glass cloth in accordance with JIS R3420:2023 and This is performed using a calibration curve that has been prepared in advance. The method for manufacturing glass cloth according to claim 2.

5. A method for manufacturing glass cloth according to any one of claims 1 to 4, wherein the measurement of the total area of ​​the basket holes per predetermined area of ​​the glass cloth and the estimation of the air permeability of the glass cloth are performed continuously in the direction of transport of the glass cloth.

6. A method for manufacturing glass cloth according to any one of claims 1 to 4, comprising winding the glass cloth into a roll after transport.

7. The method for manufacturing glass cloth according to claim 6, wherein the total length of the glass cloth wound into a roll is 200 m or more and 5,000 m or less.

8. A method for manufacturing glass cloth according to claim 6, wherein the measurement of the total area of ​​the basket holes per predetermined area of ​​the glass cloth and the estimation of the air permeability of the glass cloth are performed continuously in the direction of transport of the glass cloth.

9. A tolerance range is set for the breathability of the glass cloth. If the glass cloth has a region exhibiting a degree of permeability outside the set tolerance range, the method includes removing the region exhibiting a degree of permeability outside the set tolerance range from the glass cloth. A method for manufacturing glass cloth according to any one of claims 1 to 4.

10. A method for manufacturing a glass cloth according to any one of claims 1 to 4, wherein the dielectric constant of the glass cloth at 10 GHz is 5.0 or less.