Method and apparatus for manufacturing glass cloth

Abstract

To provide a method and apparatus for manufacturing glass cloth that enables low dielectric loss tangent of glass cloth with excellent productivity. [Solution] A method for manufacturing glass cloth, wherein the method includes a de-oiling step of irradiating the glass cloth with laser light, and the de-oiling step is performed using a roll-to-roll method.

Description

[Technical Field] 【0001】 This disclosure relates to a method for manufacturing glass cloth and an apparatus for manufacturing glass cloth. [Background technology] 【0002】 Currently, with the increasing performance of information terminals such as smartphones and the advancement of high-speed communication represented by 5G communication, there is a significant progress in reducing the dielectric constant and dielectric loss tangent of insulating materials used in printed circuit boards for high-speed communication in order to reduce transmission loss. 【0003】 Currently, information terminals such as smartphones are becoming more high-performance, and high-speed communication, exemplified by 5G communication, is progressing. Against this backdrop, for example, there is a demand for not only improved heat resistance in printed circuit boards for high-speed communication, but also for further improvement in the dielectric properties of their insulating materials (e.g., lower dielectric loss tangent). Similarly, there is a demand for improved dielectric properties in prepregs used as insulating materials for printed circuit boards, and in the glass yarns and glass cloths contained in said prepregs. 【0004】 For example, a method for constructing prepregs using low-dielectric glass is known (see Patent Documents 1 and 2). Patent Document 1 describes a method using glass yarn with a silicon dioxide (SiO2) composition of 98% to 100% by mass, and Patent Document 2 attempts to further reduce the dielectric loss tangent by heat-treating glass cloth (quartz glass cloth). 【0005】 Various reports have been published regarding heating and de-oiling methods for reducing the dielectric loss tangent of quartz glass cloth. Patent Document 3 reports that by heating and de-oiling the glass cloth in a batch oven under vacuum or in an atmosphere with a dew point of 15°C or lower, it is possible to reduce the dielectric loss tangent of the glass cloth at a lower heating and de-oiling temperature than conventional methods. Furthermore, Patent Document 4 reports that by heating and de-oiling the glass cloth while transporting it under conditions where the surface temperature of the glass cloth exceeds 650°C, the dielectric loss tangent of the glass cloth can be reduced in a very short time. [Prior art documents] [Patent Documents] 【0006】 [Patent Document 1] Japanese Patent Publication No. 2018-127747 [Patent Document 2] Japanese Patent Publication No. 2021-63320 [Patent Document 3] Japanese Patent Publication No. 2023-177400 [Patent Document 4] Japanese Patent Publication No. 2022-161665 [Overview of the Initiative] [Problems that the invention aims to solve] 【0007】 However, even in Patent Documents 1 to 4, there is room for improvement in the de-oiling treatment method for glass cloth that enables excellent productivity in reducing dielectric loss tangent. 【0008】 One of the objectives of this disclosure is to provide a method for manufacturing glass cloth and a manufacturing apparatus that enables the reduction of the dielectric loss tangent of glass cloth with excellent productivity. [Means for solving the problem] 【0009】 Some embodiments of this disclosure are illustrated below. [1] A method for manufacturing glass cloth, wherein the method is The process includes a de-oiling step, which involves irradiating the glass cloth with laser light. A method for manufacturing glass cloth, wherein the oil removal step is performed using a roll-to-roll method. [2] A method for manufacturing glass cloth according to item 1, comprising a bonding step of bonding multiple glass cloths together to each other prior to the oil removal step. [3] The method for manufacturing glass cloth according to item 1 or 2, wherein the bonding step includes bonding a plurality of glass cloths together using a heat-sealing tape. [4] The method for manufacturing a glass cloth according to any one of items 1 to 3, further comprising a cleaning step of cleaning the glass cloth with water having a sodium ion content of 20 ppm or less before the deoiling step. [5] The method for manufacturing a glass cloth according to any one of items 1 to 4, wherein the light source wavelength of the laser light in the deoiling step is in the range of 2 μm to 20 μm. [6] The method for manufacturing a glass cloth according to item 5, wherein the light source of the laser light is a CO2 laser. [7] The method for manufacturing a glass cloth according to any one of items 1 to 6, wherein in the deoiling step, automatic control of the output of the laser light is performed according to the conveyance speed of the glass cloth. [8] The method for manufacturing a glass cloth according to item 7, wherein the automatic control of the output of the laser light is performed so that the surface temperature of the glass filaments of the glass cloth is 650°C or higher and lower than the softening point of the glass filaments. [9] The method for manufacturing a glass cloth according to item 2, wherein the output of the laser light irradiated on the joint portion of the glass cloths joined in the joining step is reduced, or the joint portion is not irradiated with the laser light.

[10] The method for manufacturing a glass cloth according to any one of items 1 to 9, wherein the glass filaments of the glass cloth have a Si content in the range of 95% to 100% by mass in terms of SiO2.

[11] The method for manufacturing a glass cloth according to any one of items 1 to 10, wherein the laser light is irradiated on both surfaces of the glass cloth.

[12] The method for manufacturing a glass cloth according to any one of items 1 to 11, wherein the laser light is irradiated using 1 to 50 light sources.

[13] The method for manufacturing a glass cloth according to any one of items 1 to 12, wherein the laser light is irradiated so that the irradiation range partially overlaps in the width direction of the glass cloth.

[14] The manufacturing method of the glass cloth according to any one of items 1 to 13, wherein the laser light is irradiated so as to swing in the width direction of the glass cloth.

[15] The manufacturing method of the glass cloth according to any one of items 1 to 14, wherein the laser light is irradiated so as to diffuse in the width direction of the glass cloth.

[16] The manufacturing method of the glass cloth according to any one of items 1 to 15, wherein the laser light is irradiated so as to scan in the width direction of the glass cloth.

[17] A manufacturing apparatus for a glass cloth, wherein the manufacturing apparatus includes a conveying mechanism for conveying the glass cloth in a Roll to Roll manner, and a laser light irradiation unit for irradiating laser light onto the glass cloth being conveyed. A manufacturing apparatus for a glass cloth, comprising the above.

[18] The manufacturing apparatus for a glass cloth according to item 17, further comprising a joining mechanism for joining a plurality of the glass cloths to each other upstream of the laser light irradiation unit in the conveying direction of the glass cloth.

[19] The manufacturing apparatus for a glass cloth according to item 17 or 18, wherein the joining mechanism is configured to adhere a plurality of glass cloths to each other using a thermocompression bonding tape.

[20] The manufacturing apparatus for a glass cloth according to any one of items 17 to 19, wherein the light source wavelength of the laser light is in the range of 2 μm to 20 μm.

[21] The manufacturing apparatus for a glass cloth according to item 20, wherein the light source of the laser light is a CO2 laser.

[22] The manufacturing apparatus for a glass cloth according to any one of items 17 to 21, further comprising a cleaning mechanism for cleaning the glass cloth with water having a sodium ion content of 20 ppm or less upstream of the laser light irradiation unit in the conveying direction of the glass cloth.

[23] The laser light irradiation unit is a glass cloth manufacturing apparatus according to any one of items 17 to 22, having 1 to 50 laser light sources. [twenty four] The glass cloth manufacturing apparatus according to any one of items 17 to 23, wherein the laser light irradiation unit is configured such that the irradiation range of the laser light partially overlaps in the width direction of the glass cloth. [twenty five] The glass cloth manufacturing apparatus according to any one of items 17 to 24, wherein the laser light irradiation unit is configured to irradiate the glass cloth while oscillating the laser light in the width direction of the glass cloth.

[26] The glass cloth manufacturing apparatus according to any one of items 17 to 25, wherein the laser light irradiation unit is configured to irradiate the glass cloth by diffusing the laser light in the width direction.

[27] The glass cloth manufacturing apparatus according to any one of items 17 to 26, wherein the laser light irradiation unit is configured to irradiate the glass cloth while scanning the laser light in the width direction. [Effects of the Invention] 【0010】 According to this disclosure, it is possible to provide a method for manufacturing glass cloth and a manufacturing apparatus that enables the reduction of the dielectric loss tangent of glass cloth with excellent productivity. [Brief explanation of the drawing] 【0011】 [Figure 1] Figure 1 is a schematic diagram illustrating an example of a method in which laser light is irradiated while scanning in the width direction. [Figure 2] Figure 2 is a schematic diagram illustrating an example of a method for irradiating laser light while diffusing it in the width direction. [Modes for carrying out the invention] 【0012】 The embodiments of this disclosure will be described below, but this disclosure is not limited thereto, and various modifications are possible without departing from its essence. In these embodiments, numerical ranges indicated using "~" represent numerical ranges that include the numbers before and after "~" as the lower and upper limits, respectively. In these embodiments, in numerical ranges described in stages, the upper or lower limit indicated in one numerical range can be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in these embodiments, the upper or lower limit indicated in one numerical range can also be replaced with the values ​​shown in the examples. In these embodiments, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, as long as the function of that process is achieved. 【0013】 Method for manufacturing glass cloth The glass cloth manufacturing method of this disclosure includes a de-oiling step, which involves irradiating the glass cloth with laser light, and the de-oiling step is performed in a roll-to-roll manner. By irradiating the glass cloth with laser light in the de-oiling step, the glass cloth is heated, and sizing agents (organic substances) on the surface of the glass fibers, for example, can be removed, thereby enabling the glass cloth to have a low dielectric loss tangent. Furthermore, by performing de-oiling while conveying the glass cloth in a roll-to-roll manner, the dielectric loss tangent of the glass cloth can be reduced in a very short time, improving productivity. In addition, in conventional methods of de-oiling by heating glass cloth rolls in a batch manner, variations in dielectric loss tangent tend to occur between the surface and inner layers of the glass cloth roll, and damage to the glass cloth tends to occur on the inner layer side. In contrast, according to the glass cloth manufacturing method of this disclosure, since de-oiling is performed while conveying the glass cloth in a roll-to-roll manner, in one embodiment, it is considered that variations in dielectric loss tangent are less likely to occur over a long length of glass cloth. Furthermore, in conventional methods of degreasing glass cloth by passing it through a high-temperature heating furnace in a roll-to-roll fashion, it was necessary to lower the temperature of the heating furnace each time the glass cloth was switched. In contrast, according to the glass cloth manufacturing method of this disclosure, since the output of the laser light can be easily changed, in one embodiment, when a joint such as a heat-seal tape is transported near the laser light irradiation area, the output of the laser light can be reduced to or set to zero (laser light irradiation is stopped) below the normal operating level, and then returned to the normal operating level after the joint has passed. Therefore, the degreasing process of glass cloth can be performed at a very high production speed. 【0014】 [Oil removal process] The laser light can be any laser light capable of heating the glass cloth, and preferably includes infrared light (wavelength approximately 0.7 μm to 1000 μm). The lower limit of the laser light wavelength is preferably 0.7 μm or more, more preferably 1 μm or more, and even more preferably 2 μm or more. The upper limit of the wavelength that can be arbitrarily combined with these lower limits is preferably 1000 μm or less, more preferably 500 μm or less, even more preferably 100 μm or less, even more preferably 50 μm or less, and particularly preferably 20 μm or less. By including light within this wavelength range in the laser light, the glass cloth can be heated to a high temperature in a shorter time, and sizing agents that may adhere to the surface of the glass yarn can be removed more efficiently. 【0015】 It is preferable to use a CO2 laser not only to remove sizing agents that may adhere to the surface of glass threads, but also to dehydrate and condense the silanol groups (SiOH groups) within the glass threads. A CO2 laser is a type of gas laser that uses a gas containing CO2 (carbon dioxide) as its medium. CO2 lasers can generally emit light in the wavelength range of approximately 9.2 μm to 10.8 μm, with wavelengths centered around approximately 9.6 μm or 10.6 μm. It is generally known that quartz glass does not easily absorb light in the wavelength range of 2 μm or less. Therefore, when using quartz glass as the glass type for glass cloth, it is effective to use a CO2 laser, which is a relatively long-wavelength light source, to efficiently dehydrate and condense the silanol groups in the glass in order to reduce the dielectric loss tangent of the quartz glass. 【0016】 To more efficiently remove the sizing agent adhering to the surface of the glass thread, it is preferable to irradiate both sides of the glass cloth with laser light. The laser light may be irradiated onto both sides of the glass cloth sequentially, one side at a time, or it may be irradiated from both sides simultaneously. 【0017】 The shape and size of the spot (irradiation area when irradiated perpendicularly to a plane) per laser light source are not particularly limited, but for example, the spot diameter is preferably 1 mm to 1000 mm, more preferably 10 mm to 500 mm, and even more preferably 20 mm to 100 mm. Here, "spot diameter" is defined as the diameter of a circle that is circumscribing the shape of the spot when the laser light is irradiated perpendicularly to a plane. If the spot diameter is 1 mm or more, it is easier to irradiate the glass cloth uniformly in the width direction, and if it is 1000 mm or less, the output of the laser light is concentrated over a smaller area, so heating and oil removal can be performed more efficiently. Note that the "width direction" of the glass cloth means the direction perpendicular to the transport direction (length direction) of the glass cloth transported by the Roll to Roll method. 【0018】 From the viewpoint of more efficient heating and oil removal, the laser light output is preferably 10W to 5000W, with a lower limit of preferably 20W or more, more preferably 50W or more, and even more preferably 100W or more. The upper limit of the laser light output, which can be arbitrarily combined with these lower limits, is preferably 4000W or less, or 3000W or less. The laser light output can be appropriately adjusted depending on the width and transport speed of the glass cloth, as well as the specific mode of laser light irradiation described later, such as the number of light sources, the scanning speed of the light sources, and the degree of spot overlap. From the viewpoint of more efficient heating and oil removal, it is preferable to adjust the laser light output so that the surface temperature of the glass fibers in the glass cloth is preferably 600°C or higher, more preferably 650°C or higher, and below the softening point of the glass fibers. 【0019】 It is preferable to automatically control the laser beam output according to the glass cloth transport speed. More specifically, the automatic control preferably includes, for example, reducing the laser beam output when the glass cloth transport speed decreases, and increasing the laser beam output when the transport speed increases. Laser beam heating and de-oiling methods tend to easily supply excessive energy to the glass, but by automatically controlling the laser beam output, it is possible to perform the de-oiling process without overheating while preventing insufficient heating. From the viewpoint of more efficient heating and de-oiling, it is even more preferable to control the automatic control of the laser beam output so that the surface temperature of the glass fibers in the glass cloth is preferably 600°C or higher, more preferably 650°C or higher, and below the softening point of the glass fibers. 【0020】 In order to uniformly irradiate the glass cloth with laser light in the width direction, it is preferable to perform heat degreasing of the glass cloth by (1) irradiating while scanning (moving) the laser light in the width direction, (2) irradiating while oscillating the laser light in the width direction, (3) irradiating while diffusing the laser light in the width direction, (4) irradiating with laser light using multiple light sources, or (5) irradiating with laser light so that the irradiation ranges of the laser light partially overlap, or a combination of these methods. 【0021】 (1) Scanning of laser light Figure 1 is a schematic diagram illustrating an example of a method for irradiating glass cloth 100 while scanning it in the width direction. As schematically shown in Figure 1, laser light 220 is irradiated from the light source 210 of the laser light irradiation unit 200 onto glass cloth 100 being transported in a roll-to-roll manner. In Figure 1, the laser light irradiation unit includes one light source, but it may include multiple light sources. While transporting the glass cloth in the transport direction 110, the laser light spot 230 can be scanned back and forth across the width direction 120 as shown by the spot scanning trajectory 240. The scanning line pitch 250 can be set shorter than the spot diameter so that the spot scanning trajectory partially overlaps in the transport direction. This allows for more efficient and uniform heating and oil removal. The scanning of the laser light can be performed, for example, by continuously changing the angle of a mirror that reflects the laser light. Examples of mirrors include galvanometer mirrors. The galvanometer mirror may include, when the width direction of the glass cloth is the X-axis direction and the transport direction is the Y-axis direction, at least a first mirror that can move (scan) the laser beam spot in the X-axis direction and a second mirror that can move (scan) in the Y-axis direction. 【0022】 (2) Oscillation of laser light While not limited to a specific method, one possible method for oscillating the laser beam in the width direction is to continuously change (oscillate) the angle of a mirror that reflects the laser beam. This makes it possible to irradiate the laser beam uniformly. Examples of mirrors include the galvanometer mirror mentioned above. It is preferable that the speed at which the angle of the mirror is changed (oscillated) is constant. 【0023】 (3) Diffusion of laser light Figure 2 is a schematic diagram illustrating an example of a method for irradiating with laser light while diffusing it in the width direction. As schematically shown in Figure 2, laser light 220 is irradiated from the light source 210 of the laser light irradiation unit 200 onto a glass cloth 100 being transported in a roll-to-roll manner. In Figure 2, the laser light irradiation unit includes two light sources, but it may include one or more light sources. The laser light is diffused in the width direction using an optical device that can diffuse the laser light in the width direction, such as a beam expander 260 and a diffusion lens such as a line beam shaper 270. The shape of the diffused laser light spot 230 is linear with a predetermined width and length, and is arranged so that the length direction of the linear spot corresponds to the width direction of the glass cloth. The length of the diffused spot corresponding to the width direction of the glass cloth is preferably 50 mm to 1000 mm, more preferably 100 mm to 800 mm, and even more preferably 200 mm to 500 mm. In Figure 2, two adjacent light sources are positioned with a predetermined distance of 280 in the transport direction, and the edges of the linearly diffused spots partially overlap each other. This prevents overheating of the glass cloth in the overlapping portion 290, while enabling more efficient and uniform heating and oil removal. 【0024】 (4) Multiple light sources The number of laser light sources may be one per side of the glass cloth; however, to heat and de-oil the glass cloth over a larger area, it is preferable to have two or more, more preferably three or more, even more preferably four or more, and even more preferably five or more. The upper limit of the number of light sources that can be arbitrarily combined with these lower limits may be, for example, 50 or less per side of the glass cloth. By providing multiple laser light sources, it becomes easy to uniformly irradiate the entire surface of the glass cloth with lasers, even if the width of the glass cloth exceeds 1000 mm. 【0025】 (5) Overlap of irradiation areas The irradiation ranges (spots) of the laser beams may partially overlap. This prevents insufficient heating of the glass cloth and allows for more efficient and uniform heating and oil removal. There may be one or more light sources. The direction of the overlap may be in the width direction of the glass cloth or in the transport direction (length direction). For example, Figure 1 illustrates a method in which the laser beam is irradiated while scanning in the width direction, using one light source, in which the scanning trajectory of the spot partially overlaps in the transport direction (length direction). Figure 2 illustrates a method in which the laser beam is irradiated while diffusing in the width direction, using two light sources, in which the spots partially overlap in the width direction. 【0026】 [Joining process] The method for manufacturing glass cloth may include a joining step in which multiple glass cloths are joined together, prior to the de-oiling step described above. In a roll-to-roll method for manufacturing glass cloth, once one glass cloth roll has finished unwinding, it may be necessary to switch to the next glass cloth roll. By including a glass cloth joining step in the manufacturing method, glass cloth can be manufactured continuously, thus improving productivity. 【0027】 The method of joining is not particularly limited, but from the viewpoint of ease of operation, it is preferable to bond multiple glass cloths together using heat-sealing tape. However, in the method of heat degreasing by passing the glass cloth through a high-temperature heating furnace, the heat resistance of the joint made by the heat-sealing tape is poor, and if the joint is passed through the furnace while it is still hot, the joint may burn through. Therefore, it is necessary to lower the temperature of the heating furnace each time a switch is made and raise the temperature of the heating furnace again once the joint has passed through the furnace, which reduces productivity. In contrast, in the heat degreasing method using laser light of this disclosure, in a preferred embodiment, the output of the laser light irradiated onto the joint between glass cloths joined in the joining process can be reduced, or the laser light can not be irradiated onto the joint at all. Since the laser light output can be adjusted very easily and in a short time, the joint between glass cloths can be detected before the joint is transported to the laser light irradiation unit, and the output of the laser light can be reduced, or the laser light can not be irradiated onto the joint at all, thereby enabling the switching of glass cloths without the joint burning through. 【0028】 Reducing the laser output only requires lowering the surface temperature of the glass fibers in the glass cloth to the extent that the joint does not burn completely. For example, the output can be reduced to below 650°C, 500°C or below, 400°C or below, 300°C or below, 200°C or below, or 100°C or below. Methods to prevent the laser beam from irradiating the joint include, for example, setting the laser output to 0W (stopping it), changing the direction of laser irradiation, interposing an obstacle between the light source and the glass cloth to block the laser beam irradiation, and combinations thereof. 【0029】 From the viewpoint of further increasing productivity in the heat desorption process of glass cloth, it is preferable to perform the joining of glass cloths without stopping the transport of the glass cloth. For this reason, it is preferable that the glass cloth roll-to-roll transport mechanism (unwinding mechanism and winding mechanism) has a mechanism (accumulator) for temporarily storing the transported glass cloth. 【0030】 [Washing process] The method for manufacturing glass cloth preferably includes a washing step, prior to the de-oiling step, in which the glass cloth is washed with water containing 20 ppm or less of sodium ions. As a result of diligent research by the inventors, it was found that when the amount of Na ions and / or Mg ions adhering to the surface of the glass cloth is controlled within a predetermined range, even if the glass cloth is heated and de-oiled at high temperatures using laser light, a significant decrease in the tensile strength of the glass cloth due to glass devitrification can be suppressed. Furthermore, it was found that if the glass cloth is washed with a solvent containing low amounts of Na ions and / or Mg ions before heating and de-oiling to suppress devitrification, the amount of Na ions and / or Mg ions on the glass surface decreases, making it possible to suppress glass devitrification even when the temperature of the glass surface is high. Maintaining the strength of the glass cloth after heating and de-oiling facilitates tension control in subsequent processing steps, and as a result, cutting and other damage can be suppressed. 【0031】 From the viewpoint of easily maintaining high strength of the glass cloth after heat degreasing, it is preferable that the solvent used to wash the glass cloth is a solvent in which the amount of Na ions and / or Mg ions is controlled to predetermined levels, as shown below. 【0032】 Here, the numerical value (ppm) for the amount of ions adhering to the glass cloth surface indicates the amount of ions relative to the mass of the glass cloth, and the numerical value (ppm) for the amount of ions in the cleaning solution indicates the amount of ions relative to the mass of the cleaning solution. By cleaning the glass cloth with a cleaning solution having a predetermined Na ion concentration and / or a predetermined Mg ion concentration, the above ions on the glass cloth surface can be transferred to the cleaning solution, and the above ions in the cleaning solution can be transferred to and adhered to the glass cloth surface. 【0033】 The amount of sodium ions in the solvent used for washing is preferably 20 ppm or less, more preferably 15 ppm or less, even more preferably 12 ppm or less, even more preferably 10 ppm or less, particularly preferably 7 ppm or less, and most preferably 1.5 ppm or less. If the amount of sodium ions in the washing solution is 20 ppm or less, it is easier to reduce the amount of sodium ions adhering to the glass cloth surface, which makes it easier to suppress the devitrification phenomenon of the glass even when the temperature of the glass surface is high (for example, 600°C to 1500°C), and as a result, it is easier to ensure the tensile strength of the glass cloth. 【0034】 The amount of Mg ions in the solvent used for washing is preferably 18 ppm or less, more preferably 12 ppm or less, even more preferably 8 ppm or less, even more preferably 6 ppm or less, particularly preferably 3 ppm or less, and most preferably 1 ppm or less. If the amount of Mg ions in the washing solution is 18 ppm or less, it is easier to reduce the amount of Mg ions adhering to the glass cloth surface. This makes it easier to suppress the devitrification phenomenon of quartz glass even when the temperature of the glass surface is high (for example, 600°C to 1500°C), and as a result, it is easier to ensure the tensile strength of the glass cloth. 【0035】 From the viewpoint of suitably obtaining the effects of the present invention, it is preferable that the solvent used for cleaning the glass cloth is a solvent in which the amount of SO4 ions is controlled to a predetermined amount, as shown below. By cleaning the glass cloth with a cleaning solution of a predetermined SO4 ion concentration, the above ions on the surface of the glass cloth can be transferred to the cleaning solution, and the above ions in the cleaning solution can be transferred to and adhered to the surface of the glass cloth. 【0036】 The amount of SO4 ions in the solvent used for washing is preferably 18 ppm or less, more preferably 12 ppm or less, even more preferably 8 ppm or less, particularly preferably 6 ppm or less, and most preferably 3 ppm or less. If the amount of SO4 ions in the washing solution is 18 ppm or less, it is easier to reduce the amount of SO4 ions adhering to the glass cloth surface, and even if the temperature of the glass surface becomes high (for example, 600°C to 1500°C), it is easier to suppress the devitrification phenomenon of the glass, and as a result, it is easier to ensure the tensile strength of the glass cloth. 【0037】 To reduce the amount of ions adhering to the glass cloth surface, the means for cleaning the glass should be a method that can reduce Na ions and / or Mg ions on the glass surface, and preferably a method that can further reduce SO4 ions. For example, methods such as ultrasonic methods (e.g., methods using ultrasonic transducers), spraying (e.g., spraying with high-pressure spray), and steam spraying can be considered. From the viewpoint of inexpensive processing, a method is preferred in which the glass is immersed in a tank containing a cleaning solution (a solvent with a Na ion content of 20 ppm or less and / or a solvent with a Mg ion content of 18 ppm or less, preferably a solvent with an SO4 ion content of 18 ppm or less), the excess cleaning solution is removed with a squeeze roller or the like, and then the glass is dried. In this case, the immersion time may be, for example, 2 seconds or more, 5 seconds or more, 10 seconds or more, 15 seconds or more, or 120 seconds or less, 90 seconds or less, 60 seconds or less, or 45 seconds or less. 【0038】 Water is preferred as the solvent, and water with a Na ion content of 20 ppm or less and / or a Mg ion content of 18 ppm or less, preferably water with an SO4 ion content of 18 ppm or less, can be produced using known methods. For example, methods such as filtration using an RO membrane, deionization using an ion exchange resin, and distillation can be considered. The solvent used for washing may contain other liquid components (liquids other than water, etc.) within a range that does not hinder the effects of the present invention. The solvent may also be a lower alcohol (methanol, etc.), or a mixture of water and a lower alcohol. stomach. 【0039】 [Glass cloth] Glass cloth can have a woven structure in which glass threads (for example, glass threads consisting of multiple glass filaments) are used as warp and weft threads. Examples of woven structures for glass cloth include plain weave, twill weave, satin weave, and twill weave. Among these, the plain weave structure is preferred. 【0040】 The weft and warp thread density of the glass cloth is preferably 10 to 120 threads / inch (= 10 to 120 threads / 25 mm), and more preferably 40 to 100 threads / inch. If the weft density is within the above range, the dielectric loss tangent is easily reduced by the de-oiling process, improving productivity. The weft and warp thread densities may be the same or different. 【0041】 The basis weight (mass) of the glass cloth is preferably 8 to 250 g / m². 2 More preferably 8-100 g / m² 2 And more preferably 8-80 g / m 2 The g / m² is particularly preferably 8-50 g / m². 2 Therefore, if the basis weight of the glass cloth is within the above range, the dielectric loss tangent can be easily reduced by the de-oiling process, improving productivity. 【0042】 The coefficient of variation of the filament diameter is preferably less than 10%, more preferably 7% or less, even more preferably 5% or less, even more preferably 4% or less, and particularly preferably 3% or less. When the coefficient of variation of the glass fiber filament diameter is less than 10%, wrinkles and other defects are less likely to occur in the glass cloth when it is transported, thus improving productivity. 【0043】 [Glass thread] The glass fibers constituting the glass cloth are preferably obtained from low-dielectric glass. Specifically, the Si content of the glass fibers is preferably in the range of 95.0 to 100% by mass, in terms of SiO2. By using such glass fibers, for example, the dielectric properties of the resulting glass cloth can be improved. From the viewpoint of improving the dielectric properties of the resulting glass cloth, the Si content is preferably in the range of 99.0 to 100% by mass, more preferably in the range of 99.5 to 100% by mass, and even more preferably in the range of 99.9 to 100% by mass. 【0044】 When glass with a mass of 99.0% or more SiO2 is in a bulk state with a certain thickness, its dielectric loss tangent (bulk dielectric loss tangent) is generally given by the following formula: Bulk dielectric loss tangent ≤ 1.2 × 10⁻⁶ -3 This shows the relationship. 【0045】 The average filament diameter of the glass filaments constituting the glass yarn is preferably 2.5 to 9.0 μm, more preferably 2.5 to 7.5 μm, even more preferably 3.5 to 7.0 μm, even more preferably 3.5 to 6.0 μm, and particularly preferably 3.5 to 5.0 μm. When the filament diameter is 2.5 μm or more, the breaking strength of the filaments is high, so the resulting glass cloth is less likely to develop lint. Also, when the filament diameter is 9.0 μm or less, the mass of the glass cloth is small, making it easier to transport or process. Furthermore, if the average filament diameter of the glass filaments is within the above range, it is easier to reduce the dielectric loss tangent through the de-oiling process, and it is easier to transport and process, thus improving productivity. 【0046】 [Na ion amount and Mg ion amount] The amount of Na ions adhering to the surface of the glass cloth, for example, the amount of Na ions adhering to the surface of the glass cloth before the de-oiling process, is preferably 0 to 15 ppm. When the amount of Na ions is 15 ppm or less, the devitrification phenomenon of quartz glass can be suppressed when de-oiling is performed by heating at a high temperature (for example, 600°C or higher), and the tensile strength of the glass cloth can be easily maintained. The amount of Na ions is preferably 12 ppm or less, more preferably 8 ppm or less, even more preferably 6 ppm or less, and particularly preferably 3.5 ppm or less. If the amount of Na ions is within the above range, the devitrification phenomenon of quartz glass during de-oiling by heating can be easily suppressed. The lower limit of the amount of Na ions may be 0 or greater than 0. 【0047】 The amount of Mg ions adhering to the surface of the glass cloth, for example, the amount of Mg ions adhering to the surface of the glass cloth before the de-oiling process, is preferably 0 to 8 ppm. When the amount of Mg ions is 8 ppm or less, the devitrification phenomenon of quartz glass can be suppressed when de-oiling is performed by heating at a high temperature (for example, 600°C or higher), and the tensile strength of the glass cloth can be easily maintained. The amount of Mg ions is preferably 6 ppm or less, more preferably 4 ppm or less, even more preferably 3 ppm or less, and particularly preferably 2 ppm or less. If the amount of Mg ions is within the above range, the devitrification phenomenon of quartz glass during de-oiling by heating can be easily suppressed. The lower limit of the amount of Mg ions may be 0 or greater than 0. 【0048】 The amount of Na ions and Mg ions adhering to the surface of the glass cloth can be controlled by the cleaning process described above. Specifically, this can be controlled by cleaning the glass cloth, the ion content of the solvent used for cleaning, and the amount of sizing agent adhering to it. The amount of Na ions and Mg ions is measured by the method described in the examples. 【0049】 [SO4 ion amount] The amount of SO4 ions adhering to the surface of the glass cloth, for example, the amount of SO4 ions adhering to the surface of the glass cloth before the de-oiling process, is preferably 12 ppm or less, more preferably 10 ppm or less, even more preferably 8 ppm or less, and particularly preferably 6 ppm or less. If the amount of SO4 ions is within the above range, it is easier to suppress the devitrification phenomenon of quartz glass when de-oiling is performed by heating at a high temperature (for example, 600°C or higher), and in particular, it is easier to suppress the devitrification phenomenon caused by Mg ions. The lower limit of the amount of SO4 ions may be 0 or greater than 0. 【0050】 The amount of SO4 ions adhering to the surface of the glass cloth can be controlled by the cleaning process described above. Specifically, it can be controlled by cleaning the glass cloth, the ion content of the solvent used for cleaning, and the amount of sizing agent adhering to it. The amount of SO4 ions is measured by the method described in the examples. 【0051】 [Sizing agent] The glass cloth may be surface-treated with a sizing agent before the de-oiling process. From the viewpoint of improving the convergence of glass fibers, reducing fluff, and improving weaving properties, the sizing agent is preferably one that mainly contains at least one selected from the group consisting of starch, PVA resin, polyurethane resin, epoxy resin, and acrylic resin. From the viewpoint of suppressing fluff of the glass cloth, the sizing agent is more preferably one that mainly contains starch and / or PVA resin. Here, "main component" means the component that accounts for the largest mass % among the components constituting the sizing agent, and the "main component" can account for, for example, 50% or more by mass, 65% or more by mass, 80% or more by mass, or 95% or more by mass. 【0052】 [Loss on ignition] The ignition loss of the glass cloth, for example, the ignition loss of the glass cloth before the de-oiling process, is preferably 0.07% by mass or more and 5.0% by mass or less. The upper limit is more preferably 4.5% by mass or less, 4.0% by mass or less, 3.5% by mass or less, 3.0% by mass or less, 2.0% by mass or less, 1.8% by mass or less, or less than 1.5% by mass. The lower limit, which can be arbitrarily combined with these upper limits, is more preferably 0.07% by mass or more, 0.10% by mass or more, 0.1% by mass or more, or 0.1% by mass or more. When the ignition loss is 5.0% by mass or less, the amount of sizing agent residue adhering to the glass cloth after the de-oiling process can be reduced. As a result, the dielectric loss tangent of the glass cloth is further reduced, and the Na ions and / or Mg ions adhering to the glass cloth surface can be effectively reduced by washing before the de-oiling process. Furthermore, if the ignition loss value is 0.07% by mass or higher, the effect of improving convergence as a sizing agent is enhanced, resulting in less fuzzing and damage to the resulting cloth, and thus further improving productivity. 【0053】 The ignition loss can be controlled, for example, by the amount of sizing agent adhering to the glass yarn and the washing conditions of the glass yarn. The ignition loss is measured in accordance with JIS R3420. 【0054】 [Dielectric loss tangent of glass cloth after de-oiling process] The dielectric loss tangent of the glass cloth at 10 GHz after the de-oiling process is preferably 0.001 or less, more preferably 0.0008 or less, even more preferably 0.0007 or less, even more preferably 0.0006 or less, and particularly preferably 0.0004 or less. If the dielectric loss tangent is 0.001 or less, it is easier to improve the dielectric properties of the printed circuit board. If the dielectric loss tangent at 10 GHz is 0.00035 or less, 0.00033 or less, or 0.00030 or less, it is even easier to improve the dielectric properties. 【0055】 Glass cloth manufacturing equipment The glass cloth manufacturing apparatus of this disclosure comprises a conveying mechanism for conveying glass cloth in a roll-to-roll manner and a laser light irradiation unit for irradiating the glass cloth with laser light while it is being conveyed. As a result, the glass cloth manufacturing apparatus of this disclosure can carry out the glass cloth manufacturing method of this disclosure, and as described above, it is possible to reduce the dielectric loss tangent of the glass cloth with excellent productivity. In one embodiment, the glass cloth manufacturing apparatus of this disclosure can be a manufacturing apparatus equipped with a roll-to-roll conveying path that is independent of other processes (e.g., joining process, washing process, and fiber opening process after de-oiling process) if it is possible to use a roll of glass cloth that has already been woven and optionally surface-treated with a sizing agent as raw material (raw material) and heat-de-oil it with laser light to obtain a roll of heat-de-oiled glass cloth. Alternatively, the manufacturing apparatus may be configured to optionally carry out other processes on the same roll-to-roll conveying path. 【0056】 [Conveying mechanism] The conveying mechanism can convey glass cloth in a roll-to-roll manner. More specifically, the conveying mechanism includes, for example, an unwinding device that serves as the starting point of the roll-to-roll process, a winding device that serves as the ending point, one or more guide rolls positioned between the unwinding device and the winding device, and a drive device, etc. The glass cloth manufacturing apparatus may include a laser irradiation unit, etc., between the unwinding device and the winding device. 【0057】 [Laser irradiation unit] The laser irradiation unit comprises one or more light sources that emit laser light, and optionally at least one mechanism selected from the group consisting of a mechanism for scanning the laser light, a mechanism for oscillating the laser light, and a mechanism for diffusing the laser light. Regarding the light sources, the wavelength of the laser light source is as described above in the manufacturing method section, and is preferably in the range of 2 μm to 20 μm. The light source of the laser light is as described above in the manufacturing method section, and is preferably a CO2 laser. 【0058】 The laser irradiation unit is preferably configured to automatically control the output of the laser light according to the transport speed of the glass cloth, and it is more preferable to control the temperature so that the surface temperature of the glass fibers of the glass cloth is 600°C or higher, preferably 650°C or higher, and below the softening point of the glass fibers. The output can be controlled using a sensor for detecting the transport speed of the glass cloth, and an information processing device that is communicatively connected to the sensor and the laser irradiation unit. Details regarding the control of the laser light output are as described above in the manufacturing method section. 【0059】 In order to uniformly irradiate the glass cloth with laser light in the width direction, it is preferable that the laser light irradiation unit is configured to (1) irradiate while scanning (moving) the laser light in the width direction of the glass cloth; (2) irradiate while oscillating the laser light in the width direction; (3) irradiate while diffusing the laser light in the width direction; (4) irradiate with laser light using multiple light sources; (5) irradiate with laser light such that the irradiation ranges of the laser light partially overlap; or a combination of these configurations. Detailed embodiments of these configurations are described above in the section on manufacturing methods. 【0060】 [Joining mechanism] Upstream of the laser irradiation unit in the glass cloth transport direction, the system further includes a joining mechanism for joining multiple glass cloths together. The joining mechanism is preferably configured to bond multiple glass cloths together using heat-sealable tape. From the viewpoint of further increasing productivity in the heat desorption process of the glass cloth, the joining mechanism is preferably configured to allow joining of glass cloths without stopping the transport of the glass cloths. Therefore, the joining mechanism preferably includes a mechanism (accumulator) for temporarily storing the transported glass cloths. 【0061】 The glass cloth manufacturing apparatus preferably includes, in front of the laser irradiation unit, a mechanism for detecting the joints of the glass cloth, and a mechanism for reducing the output of the laser light irradiated onto the joints in response to the detection of the joints, or for preventing laser light from irradiating the joints. Such control can be performed using a sensor for detecting the joints of the glass cloth, and an information processing device that is communicatively connected to the sensor and the laser irradiation unit, etc. 【0062】 [Cleaning mechanism] It is preferable to further provide a cleaning mechanism upstream of the laser irradiation unit in the glass cloth transport direction for cleaning the glass cloth with water containing 20 ppm or less of sodium ions. Examples of cleaning mechanisms include a spray device, a tank for storing cleaning solution, an ultrasonic vibrator, a squeeze roller, and a drying device. The detailed aspects of the cleaning are as described above in the manufacturing method section. 【0063】 Method for measuring the dielectric loss tangent of glass cloth The dielectric loss tangent of glass cloth can be measured using the resonance method. Since the resonance method is suitable for evaluating low-loss materials in the high-frequency range, the measurement method using the resonance method allows for simpler and more accurate measurements compared to conventional measurement methods that require the fabrication of a substrate as a measurement sample to evaluate dielectric properties. Other known dielectric property evaluation methods include the lumped parameter method and the reflection transmission method. The lumped parameter method requires the formation of a capacitor by sandwiching the measurement sample between two electrodes, making the operation very complicated. The reflection transmission method has problems in that, when evaluating low-loss materials, the influence of port matching characteristics is strongly apparent, making it difficult to evaluate the dielectric loss tangent of the sample with high accuracy. For these reasons, the resonance method is preferred for evaluating the dielectric properties of the glass cloth in question. 【0064】 In this measurement process, preferred measuring instruments using the resonance method include a split cylinder resonator, an open resonator, and an NRD guide excited dielectric resonator. However, as long as the principle of the resonance method is utilized, the dielectric properties of the glass cloth may be evaluated using measuring instruments other than the above-mentioned ones. 【0065】 To measure the dielectric properties of the above-mentioned glass cloth used for high-speed communication printed wiring boards, the measurable range of the measuring instrument is, for the dielectric constant (Dk) and the dielectric loss tangent (Df), Dk = 1.1 to 50 and Df = 1.0×10 -6 ~1.0×10 -1 respectively, with a range of Dk = 1.5 to 10 and Df = 1.0×10 -5 ~5.0×10 -1 being more preferred, and a range of Dk = 2.0 to 5 and Df = 5.0×10 -5 ~1.0×10 -2 being even more preferred. 【0066】 The measurable frequency of the measuring instrument is preferably 10 GHz or higher. When the frequency is 10 GHz or higher, it is possible to evaluate the characteristics in the frequency band region assumed when actually used as the glass cloth for the substrate of a high-speed communication printed wiring board. 【0067】 To measure the dielectric properties of the glass cloth over a larger area and determine whether the measurement results are within the range of preset reference values, the measurement area of this measurement method is preferably 10 mm 2 or more. The measurement area of this measurement method is more preferably 15 mm 2 or more, and even more preferably 20 mm 2 or more. 【Examples】 【0068】 Next, the present invention will be further described in more detail with reference to examples and comparative examples. The present invention is not limited in any way by the following examples. Various evaluation methods will also be described below. 【0069】 《Measurement and Evaluation Methods》 [Method for measuring the thickness of glass cloth] In accordance with JIS R3420, section 7.10, which specifies general test methods for glass fibers and glass cloths using glass fibers, a micrometer was used. The spindle was rotated gently and lightly brought into contact with the measuring surface parallel to it, and the scale reading was taken after the ratchet clicked three times. 【0070】 [Method for measuring the basis weight (weight of glass cloth)] The basis weight of the cloth was determined by cutting the cloth to a predetermined size and dividing its weight by the sample area. In this example, glass cloth was 10 cm 2 The basis weight of each fiberglass cloth was determined by cutting it to the appropriate size and measuring its weight. 【0071】 [Average filament diameter of glass fiber] The cross-sections of 30 glass filament bundles at arbitrary positions were observed using a scanning electron microscope, and the average value was calculated to determine the average filament diameter. 【0072】 [Converted Thickness] Since glass cloth is a discontinuous planar material composed of air and glass, the equivalent thickness required for measurement using the resonance method was calculated by dividing the basis weight of each glass cloth by the density of the glass. Equivalent thickness (μm) = Basis weight (g / m²) 2 ) ÷ density of glass (g / cm³) 3 ) 【0073】 [Method for measuring dielectric loss tangent] In accordance with JIS R1641 / IEC 62562, which specifies a method for measuring the dielectric properties of fine ceramic materials used as dielectric substrates, primarily for microwave circuits, in the microwave band, the dielectric loss tangent of each glass cloth was measured. Specifically, glass cloth samples, sampled to the size required for measurement in each resonator, were conditioned by storing them in a constant temperature and humidity oven at 23°C and 50%RH for at least 8 hours, and then measured using a split cylinder resonator (EM Labs) and an impedance analyzer (Agilent Technologies). Measurements were performed five times for each sample, and the average value was calculated. The thickness of each sample was measured using the above-mentioned converted thickness. 【0074】 [Loss on ignition] The ignition loss of glass was determined in accordance with JIS R3420. Specifically, the glass cloth was dried at a temperature of 110°C ± 5°C for 60 minutes. Then, it was transferred to a desiccator and allowed to cool at room temperature for 20 minutes, after which the mass of the test specimen was weighed to the nearest 0.1 mg (A mg). The dried test specimen was then heat-treated at a temperature of 625°C ± 20°C for 20 minutes. Then, it was transferred to a desiccator and allowed to cool for 20 minutes, after which the mass of the test specimen was weighed to the nearest 0.1 mg (B mg). The ignition loss was calculated using the following formula and rounded to the third decimal place. Loss on ignition (%) = (A (mg) - B (mg)) / A (mg) × 100 【0075】 [Measurement of Na ion, Mg ion, and SO4 ion content in the washing solution] The amounts of Na ions, Mg ions, and SO4 ions in the washing solution used to clean the glass cloth before heating and degreasing were measured using an ion chromatograph. <Pretreatment conditions> Samples were prepared by diluting them with distilled water as needed. <Cation Ion Chromatography Conditions> Equipment:Tosoh,IC-2010 Separation column: Tosoh, TSKgel-Super IC-Cation / P (4.6mm x 150mm) Separated solution: 2.5 mM HNO3 + 0.5 mM L-histidine Flow rate: 1.0mL / min Detection: Electrical conductivity Column temperature: 40℃ Injection volume: 30μL <Anion Ion Chromatography Conditions> Equipment:Tosoh,IC-2010 Separation column: Tosoh, TSKgel-Super IC-AZ (4.6mm x 150mm) Eluent: 6.3mM NaHCO3+1.7mM Na2CO3 Flow rate: 0.8mL / min Detection: Electrical conductivity Column temperature: 40℃ Injection volume: 30μL 【0076】 [Measurement of the amount of Na ions, Mg ions, and SO4 ions adhering to the surface of the glass cloth before heating and degreasing.] The amount of Na ions and Mg ions adhering to the surface of glass cloth (raw material cloth) before heating and de-oiling was measured using an ion chromatograph. <Pretreatment conditions> A piece of glass cloth cut to 18cm x 7cm was placed in a clean bottle (Wakayama CIC Laboratory Clean Pack Good Boy 100ml (SCC: ultrapure water washed), AS ONE part number: 7-2214-01). Next, it was immersed in 10ml of distilled water at room temperature and then irradiated with ultrasound for 30 minutes. After that, it was left to stand overnight at room temperature of 20℃~25℃ (for example, 23℃), and then centrifuged (12000rpm x 15 minutes). The supernatant liquid, from which foreign matter from the glass cloth had been removed, was used as the sample. The supernatant liquid obtained by performing the same procedure without glass cloth was used as a blank. The amount of Na ions and Mg ions (ppm) attached to the surface of the glass cloth was determined using the following formula. The amount of each ion (ppm) adhering to the surface of the glass cloth = (Amount of each ion in the supernatant containing the glass cloth (μg / ml) - Amount of each ion in the supernatant of the blank (μg / ml)) × 10 (ml) / Mass of the glass cloth (g) <Cation Ion Chromatography Conditions> Equipment:Tosoh,IC-2010 Separation column: Tosoh, TSKgel-Super IC-Cation / P (4.6mm x 150mm) Eluent: 2.5 mM HNO3 + 0.5 mM L-histidine Flow rate: 1.0mL / min Detection: Electrical conductivity Column temperature: 40℃ Injection volume: 30μL 【0077】 [Sizing agent A: Polyvinyl alcohol resin] Sizing agent A, mainly composed of polyvinyl alcohol (PVA) resin, was applied to glass yarn used to produce raw cloth using the following procedure. An aqueous solution with a concentration of 5% PVA (product name: PVA403, manufactured by Kuraray Co., Ltd.) was prepared, and 2% hydrogenated castor oil was added to this aqueous solution as a lubricant to obtain sizing agent A. Sizing agent A, which had been kept warm at 60°C, was applied to the glass yarn. 【0078】 [Manufacturing of Q1035 (raw fabric cloth)] Using glass yarn with an SiO2 composition content greater than 99.9% by mass, a cloth was woven in an air-jet loom at a weaving density of 66 warp threads / 25 mm and 68 weft threads / 25 mm. The cloth width was woven to 1300 mm. As the warp threads, quartz glass yarn with an average filament diameter of 5.0 μm, 100 filaments, and 1.0 Z twist was used. Similarly, as the weft threads, quartz glass yarn with an average filament diameter of 5.0 μm, 100 filaments, and 1.0 Z twist was used. 【0079】 [Ion content in the cleaning solution] The amounts of Na ions, Mg ions, and SO4 ions in washing solution 1 are as shown in the table below. Na ion content = 1.6 ppm Mg ion content = 0.0 ppm SO4 ion content = 0.0 ppm 【0080】 [The process of joining glass cloths together] To switch between the glass cloths, we used Maxell's heat-seal adhesive tape (product name: SLIONTEC N0.5200) to heat-seal and bond the glass cloths together. 【0081】 Examples and Comparative Examples [Example 1] A raw cloth Q1035 was obtained using glass yarn to which sizing agent A was attached. The obtained cloth was transported at a line speed (transport speed = 30 m / min) while being immersed in a water tank containing washing water 1 for 20 seconds to wash away ions attached to the glass surface. After that, the moisture attached to the glass cloth was removed by heating it at 110°C for 15 seconds in a dryer installed on the same line (drying process). 【0082】 Subsequently, the glass cloth of Example 1 was de-oiled by heating with a CO2 laser beam, which was also installed on the same line. Here, 20 laser beams (spot diameter = 0.1 mm) were arranged on both the front and back surfaces of the glass cloth, and they were oscillated so that there were no areas in the width direction of the glass cloth that were not illuminated by the laser beam, and each laser beam was uniformly irradiated in the width direction of the glass cloth. During this process, the output of the laser beam was automatically controlled according to the glass cloth transport speed so that the glass cloth surface temperature was in the range of 1000 to 1050°C. In the joining process where glass cloths were switched, the above de-oiling treatment was performed using an accumulator without stopping the transport of the glass cloth. In addition, the laser beam irradiation unit was equipped with a sensor to detect the joint of the glass cloth before the de-oiling process, and the output of the laser beam was set to 0W the moment the sensor detected the joint. As a result, the heat-sealable tape used at the joint was not burned out, and the glass cloth could be transported. 【0083】 [Example 2] A laser irradiation unit equipped with a diffusion lens that diffuses CO2 laser light to a length of 300 mm in the width direction was used to perform a heating and de-oiling process on glass cloth. Here, five laser beams were arranged on both the front and back surfaces of the glass cloth, fixed in a longitudinal position so that there were no areas of the glass cloth that were not exposed to the laser light in the width direction, and so that the glass cloth would not melt due to excessive energy. During this process, the laser beam output was automatically controlled so that the glass cloth surface temperature was in the range of 1000 to 1050°C, according to the glass cloth transport speed. In the joining process, where glass cloths were switched, the above heating and de-oiling treatment was performed using an accumulator without stopping the transport of the glass cloth. Furthermore, the laser irradiation unit was equipped with a sensor that detects the joint of the glass cloth before the heating and de-oiling process, and the laser beam output was reduced to 0W the moment the sensor detected a joint. As a result, the heat-sealable tape used at the joint was not burned, and the glass cloth could be transported. 【0084】 [Comparative Example 1] The procedure was the same as in Example 1, except that the glass cloth was passed through an electric furnace set to an ambient temperature of 1000°C for 10 seconds to remove the oil by heating. The heat-sealing tape used for joining the glass cloths burned out in the electric furnace, making it impossible to switch the glass cloths. 【0085】 [Table 1] [Explanation of symbols] 【0086】 100 glass cloth 110 Conveying direction 120 Width direction 200 Laser beam irradiation units 210 Light source 220 laser light 230 spots The trajectory of 240 spot scans 250 line pitch 260 Beam Expander 270 Line Beam Shaper 280 interval 290 Overlap portion

Claims

[Claim 1] A method for manufacturing glass cloth, wherein the method is The process includes a de-oiling step, which involves irradiating the glass cloth with laser light. A method for manufacturing glass cloth, wherein the oil removal step is performed using a roll-to-roll method. [Claim 2] A method for manufacturing glass cloth according to claim 1, further comprising a bonding step of bonding a plurality of glass cloths together to one another, prior to the oil removal step. [Claim 3] The method for manufacturing glass cloth according to claim 1 or 2, wherein the bonding step includes bonding a plurality of glass cloths together using a heat-sealable tape. [Claim 4] A method for producing glass cloth according to claim 1 or 2, further comprising a washing step of washing the glass cloth with water containing 20 ppm or less of sodium ions prior to the oil removal step. [Claim 5] The method for manufacturing glass cloth according to claim 1 or 2, wherein the wavelength of the laser light source in the oil removal step is in the range of 2 μm to 20 μm. [Claim 6] The aforementioned laser light source is CO ２ A method for manufacturing glass cloth according to claim 5, wherein the laser is used. [Claim 7] The method for manufacturing glass cloth according to claim 1 or 2, wherein in the de-oiling step, the output of the laser light is automatically controlled according to the conveying speed of the glass cloth. [Claim 8] The method for manufacturing a glass cloth according to claim 7, wherein the automatic control of the output of the laser light is controlled so that the surface temperature of the glass fibers of the glass cloth is 650°C or higher and below the softening point of the glass fibers. [Claim 9] The method for manufacturing glass cloth according to claim 2, wherein the output of the laser light irradiated onto the joint portion of the glass cloths joined in the joining step is reduced, or the laser light is not irradiated onto the joint portion. [Claim 10] The glass fibers of the aforementioned glass cloth have a Si content of SiO ２ A method for producing glass cloth according to claim 1 or 2, wherein the amount is in the range of 95% to 100% by mass when converted. [Claim 11] The method for manufacturing a glass cloth according to claim 1 or 2, wherein the laser light is irradiated onto both sides of the glass cloth. [Claim 12] A method for manufacturing glass cloth according to claim 1 or 2, wherein the laser light is irradiated using 1 to 50 light sources. [Claim 13] The method for manufacturing a glass cloth according to claim 1 or 2, wherein the laser light is irradiated such that the irradiation range of the laser light partially overlaps in the width direction of the glass cloth. [Claim 14] The method for manufacturing a glass cloth according to claim 1 or 2, wherein the laser light is irradiated so as to oscillate in the width direction of the glass cloth. [Claim 15] The method for manufacturing a glass cloth according to claim 1 or 2, wherein the laser light is irradiated so as to diffuse in the width direction of the glass cloth. [Claim 16] The method for manufacturing a glass cloth according to claim 1 or 2, wherein the laser light is irradiated so as to scan in the width direction of the glass cloth. [Claim 17] A glass cloth manufacturing apparatus, the manufacturing apparatus, A conveying mechanism for transporting the aforementioned glass cloth in a roll-to-roll manner, A laser beam irradiation unit that irradiates the glass cloth with laser light while it is being transported. A glass cloth manufacturing apparatus equipped with the following features. [Claim 18] The glass cloth manufacturing apparatus according to claim 17, further comprising a joining mechanism for joining a plurality of glass cloths together, upstream of the laser light irradiation unit in the direction of transporting the glass cloth. [Claim 19] The glass cloth manufacturing apparatus according to claim 17 or 18, wherein the bonding mechanism is configured to bond a plurality of glass cloths together using a heat-sealing tape. [Claim 20] The apparatus for manufacturing glass cloth according to claim 17 or 18, wherein the wavelength of the laser light source is in the range of 2 μm to 20 μm. [Claim 21] The aforementioned laser light source is CO ２ A laser is used in the apparatus for manufacturing glass cloth according to claim 20. [Claim 22] The glass cloth manufacturing apparatus according to claim 17 or 18, further comprising a cleaning mechanism upstream of the laser light irradiation unit in the glass cloth transport direction, for washing the glass cloth with water containing 20 ppm or less of sodium ions. [Claim 23] The glass cloth manufacturing apparatus according to claim 17 or 18, wherein the laser light irradiation unit has 1 to 50 laser light sources. [Claim 24] The glass cloth manufacturing apparatus according to claim 17 or 18, wherein the laser light irradiation unit is configured such that the irradiation range of the laser light partially overlaps in the width direction of the glass cloth. [Claim 25] The glass cloth manufacturing apparatus according to claim 17 or 18, wherein the laser light irradiation unit is configured to irradiate the glass cloth while oscillating the laser light in the width direction of the glass cloth. [Claim 26] The glass cloth manufacturing apparatus according to claim 17 or 18, wherein the laser light irradiation unit is configured to irradiate the glass cloth by diffusing the laser light in the width direction. [Claim 27] The glass cloth manufacturing apparatus according to claim 17 or 18, wherein the laser light irradiation unit is configured to irradiate the glass cloth while scanning the laser light in the width direction.

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