Method for manufacturing glass yarn and glass cloth, and glass cloth

Abstract

To provide a glass cloth having little defect, a method of producing the same, and a glass yarn constituting the same.SOLUTION: A glass cloth is produced by weaving a glass yarn including a plurality of glass filaments as a warp yarn and a weft yarn, where the point deduction rate expressed by a point deduction rate (%)=(a total of defect counts / 500)×100 is 0-3.5% when counting one as a defect point in the case that a whole area fuzz exists on the cloth face by irradiating 500 m of a lengthwise direction of the glass cloth along its cloth face with white LED light, and observing every one m in a lengthwise direction.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for manufacturing glass fibers and glass cloths, and glass cloths.

Background Art

[0002] With the development of the information and communication society in recent years, data communication and / or signal processing are being carried out in large volumes and at high speeds. Printed wiring boards are used in high-end servers, high-end routers / switches, supercomputers, communication equipment for base stations, measuring instruments, etc., and the dielectric constant of printed wiring boards is decreasing. Therefore, low-dielectric glass cloths have been proposed for glass cloths constituting printed wiring boards. For example, Patent Document 1 discloses that, for conventionally used E-glass cloths, by increasing the amount of boron trioxide (B2O3) in the glass composition and adjusting the amounts of other components such as silicon dioxide (SiO2), the dielectric constant of the glass cloth is reduced.

[0003] Regarding terminal electronic devices such as smartphones, since they are required to support communication with large capacity and high speed, the reduction of the dielectric constant of printed wiring boards used for smartphones has also been increasing in recent years. Therefore, thin (for example, having a thickness of 10 to 50 μm) low-dielectric glass cloths have been strongly demanded.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

[0005] The inventors have found that the low-dielectric glass cloth described in Patent Document 1 exhibits variability in performance or quality compared to conventionally known E-glass cloths. In particular, low-dielectric glass cloths with a thickness of 10 to 50 μm tend to exhibit significant variability in fluff quality, making it difficult to obtain glass cloths with consistently excellent fluff quality.

[0006] As methods for improving the fluff quality of glass cloth, Patent Documents 2 and 3 disclose a method using a specific starch as a sizing agent for glass yarn, Patent Document 4 discloses a method for smoothing the bending of yarn in a traveler during glass yarn manufacturing, and Patent Document 5 discloses a method using a specific composition for low-dielectric glass.

[0007] Patent Document 2 discloses that by manufacturing glass cloth using glass yarn produced with a sizing agent containing starch composed of 25 to 100% by mass of amylose, and in which the average particle size of the starch is 12 μm or less, the fluffing of the cloth can be suppressed.

[0008] Patent Document 3 discloses that by preparing glass yarn to which 1.5 to 3.0% by mass of a sizing agent containing etherified high-amylose starch with an amylose content of 50% or more is attached, the sizing properties of the glass yarn can be improved, thereby effectively preventing the generation of fluff.

[0009] Patent Document 4 discloses that in the twisting process for glass yarn manufacturing, by making the yarn passage section of the traveler thicker and making the bending of the yarn as it passes through the traveler gentler, it becomes less likely for quality defects such as fuzzing, yarn breakage, and loops to occur.

[0010] Patent Document 5 discloses that by forming a low-dielectric glass containing Fe2O3 as part of a glass composition expressed in weight percent as 50≦SiO2≦56, 20≦B2O3≦30, 10≦Al2O3≦20, 3.5≦MgO+CaO≦10, and 0≦R2O≦1.0 (wherein R is at least one element selected from Li, Na, and K), it is possible to suppress thread breakage or fuzzing during glass thread processing.

[0011] It is presumed that low-dielectric glass yarn is weaker in strength than conventionally used E-glass yarn, and because glass cloth manufactured using commercially available low-dielectric glass yarn exhibits significant variations in fluff quality, a low-dielectric glass yarn that can consistently produce high-quality glass cloth has not yet been obtained.

[0012] For example, using glass yarn with fewer defects makes it easier to improve the quality of glass cloth. In recent years, as the required quality of glass cloth has increased, there has been a demand for glass cloth that can meet such expectations of quality improvement. For example, low dielectric resins tend to have high molecular weights or bulky functional groups, and may have inferior varnish impregnation properties compared to conventional resins, so there has been a need for high impregnation properties on the glass cloth side.

[0013] This invention has been made in view of the above-mentioned problems, and aims to provide glass yarn with few defects, to provide glass cloth with high uniformity and good quality using such glass yarn, and ultimately to provide a method for manufacturing the same. [Means for solving the problem]

[0014] The inventors of the present invention, after diligently studying to solve the above problems, focused on the fact that minute fluff can only be detected by predetermined visual observation, and thus completed the present invention. One aspect of the present invention is listed below. [1] A glass cloth woven using glass threads containing multiple glass filaments as both warp and weft threads, When a 500m length of the aforementioned glass cloth is irradiated with white LED light along its surface and observed every 1m along the length, and when the presence of fuzz across the entire surface of the cloth is counted as 1 defect, the following formula is used: Deduction rate (%) = (Total number of defects / 500) × 100 Glass cloth with a deduction rate of 0-3.5%, as shown by [formula]. [2] The glass cloth according to item 1, wherein the overall fluffiness includes fluffing of 200 to 1000 μm due to the breakage of the filaments, as observed on the cloth surface by optical microscope. [3] The glass cloth according to item 1 or 2, wherein the thickness of the glass cloth is 10 to 50 μm. [4] The following conditions: (i)TEX is 1 to 13, (ii) The breaking strength is 0.50 to 0.80 N / tex, and (iii) The number of slipped filaments is 3 or less, and is 2 times or more the average thread width when measured over 180m. A glass cloth according to any one of items 1 to 3, including the glass yarn that satisfies the requirements. [5] A glass cloth according to any one of items 1 to 4, comprising the glass yarn having a twist interval length of 1.8 to 10.0 cm. [6] A glass cloth according to any one of items 1 to 5, including the glass yarn, wherein the value obtained by dividing the difference between the maximum and minimum twist interval lengths of the glass yarn by the average value of the twist interval lengths (twist interval length difference index) is 0.7 or less. [7] Targeting the glass yarn having a length of 10,000m or more, The glass cloth described in any one of items 1 to 6, wherein when a measurement range of 180 m in the length direction is selected at five different locations, the number of filaments that have slipped out to more than twice the average thread width is 3 or less in each of the five measurement ranges. [8] Targeting the glass yarn having a length of 50,000m or more, The glass cloth described in any one of items 1 to 6, wherein when a measurement range of 180 m in the length direction is selected at seven different locations, the number of filaments that have slipped out is 3 or less in each of the seven measurement ranges, and the number of filaments that have slipped out is 2 times or more the average yarn width. [9] Targeting the glass yarn having a length of 100,000 m or more, The glass cloth described in any one of items 1 to 6, wherein when a measurement range of 180 m in the length direction is selected at 10 different locations, the number of filaments that have slipped out to more than twice the average thread width is 3 or less in each of the 10 measurement ranges.

[10] A method for manufacturing glass cloth, comprising the step of weaving using glass yarn containing multiple glass filaments as warp and weft threads, (i) The TEX of the glass yarn is 1 to 13, (ii) The breaking strength of the glass fiber is 0.50 to 0.80 N / tex, and (iii) The number of slipped filaments is 3 or less, and is 2 times or more the average thread width when measured over 180m. A method for manufacturing glass cloth.

[11] The method for manufacturing glass cloth according to item 10, wherein the TEX of the glass yarn is 1 to 7.

[12] A method for manufacturing glass cloth according to item 10 or 11, wherein the number of monoglass filaments constituting the glass thread is 30 to 120.

[13] A method for manufacturing glass cloth according to any one of items 10 to 12, wherein the twist interval length of the glass yarn is 1.8 to 10.0 cm.

[14] A method for manufacturing glass cloth according to any one of items 10 to 13, wherein the value obtained by dividing the difference between the maximum and minimum twist interval lengths of the glass yarn by the average value of the twist interval lengths (twist interval length difference index) is 0.7 or less.

[15] The density of the glass fiber is 2.2 g / cm³. 3 More than 2.5g / cm 3 A method for manufacturing glass cloth as described in any one of items 10 to 14, wherein the result is less than [amount missing].

[16] A method for manufacturing glass cloth according to any one of items 10 to 15, wherein the elastic modulus of the glass yarn is 50 to 70 GPa.

[17] A method for manufacturing glass cloth according to any one of items 10 to 16, wherein the elastic modulus of the glass yarn is 50 to 63 GPa.

[18] Targeting the glass yarn having a length of 10,000m or more, A method for manufacturing glass cloth according to any one of items 10 to 17, wherein when a measurement range of 180 m in the longitudinal direction is selected at five different locations, the number of filaments that have slipped off is 3 or less in each of the five measurement ranges, and the number of filaments that have slipped off is 2 times or more the average yarn width.

[19] Targeting the glass yarn having a length of 50,000m or more, A method for manufacturing glass cloth according to any one of items 10 to 17, wherein when a measurement range of 180 m in the longitudinal direction is selected at seven different locations, the number of filaments that have slipped out to more than twice the average yarn width is 3 or less in each of the seven measurement ranges.

[20] Targeting the glass yarn having a length of 100,000 m or more, A method for manufacturing glass cloth according to any one of items 10 to 17, wherein when a measurement range of 180 m in the longitudinal direction is selected at 10 different locations, the number of filaments that have slipped off is 3 or less in each of the 10 measurement ranges, which is 2 times or more the average yarn width. [twenty one] (i)TEX is 1 to 13, (ii) The breaking strength is 0.50 to 0.80 N / tex, and (iii) The number of slipped filaments is 3 or less, and is 2 times or more the average thread width when measured over 180m. Glass thread. [twenty two] The glass yarn described in item 21, wherein the TEX is 1 to 7. [twenty three] The glass yarn according to item 21 or 22, wherein the number of monoglass filaments constituting the glass yarn is 30 to 120. [twenty four] Glass yarn as described in any one of items 21-23, with a twist interval length of 1.8-10.0 cm. [twenty five] Glass yarn as described in any one of items 21 to 24, wherein the value obtained by dividing the difference between the maximum and minimum twist interval lengths by the average twist interval lengths (twist interval length difference index) is 0.7 or less.

[26] The density is 2.2 g / cm³. 3 More than 2.5g / cm 3 A glass fiber described in any one of items 21-25, which is less than [amount missing].

[27] A glass fiber described in any one of items 21 to 26, having an elastic modulus of 50 to 70 GPa.

[28] A glass fiber described in any one of items 21 to 27, having an elastic modulus of 50 to 63 GPa.

[29] Targeting the glass yarn having a length of 10,000m or more, The glass yarn described in any one of items 21 to 28, wherein when a measurement range of 180 m in the length direction is selected at five different locations, the number of filaments that have slipped out to more than twice the average yarn width is 3 or less in each of the five measurement ranges.

[30] Targeting the glass yarn having a length of 50,000m or more, The glass yarn described in any one of items 21 to 28, wherein when a measurement range of 180 m in the length direction is selected at seven different locations, the number of filaments that have slipped out to more than twice the average yarn width is 3 or less in each of the seven measurement ranges.

[31] Targeting the glass yarn having a length of 100,000 m or more, The glass yarn described in any one of items 21 to 28, wherein when a measurement range of 180 m in the length direction is selected at 10 different locations, the number of filaments that have slipped out to more than twice the average yarn width is 3 or less in each of the 10 measurement ranges. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide glass yarn with few defects, and using such glass yarn, it is possible to provide glass cloth with high uniformity and good quality, and furthermore, a method for manufacturing the same can be provided. [Modes for carrying out the invention]

[0016] The embodiments of the present invention (hereinafter referred to as "embodiments") will be described in detail below, but the present invention is not limited thereto, and various modifications are possible without departing from its essence.

[0017] [Glass cloth] The first embodiment of the present invention is glass cloth.

[0018] The glass cloth of this embodiment is A glass cloth woven using glass yarn containing multiple glass filaments (hereinafter also simply referred to as "filaments") as warp and weft threads, where a predetermined measurement length of 500 m of the total length of the glass cloth is observed by irradiating each 1 m lengthwise surface of the cloth with white LED light, and when the presence of fuzz across the entire surface of the cloth is counted as 1 defect, the following formula is used: Deduction rate (%) = Total number of fibers counted across the entire surface / 500 (m) × 100 The penalty rate, expressed as , ranges from 0 to 3.5%.

[0019] In this embodiment, by irradiating the cloth surface with white LED light along the cloth surface and observing it, filament breaks less than 1 mm in length (hereinafter also referred to as "minute fluff") can be detected with higher sensitivity compared to conventional observation by irradiating the cloth surface perpendicular to the cloth surface. Furthermore, because the deduction rate derived under such a detection method is 0 to 3.5%, there are fewer defects as a glass cloth, and consequently, it exhibits excellent properties in various aspects. From a similar viewpoint, the deduction rate is preferably 3.0% or less, and more preferably 2.9% or less. Furthermore, conventional observation methods (conventional observation using light irradiation perpendicular to the cross surface) were not designed to observe minute fluff. Therefore, using conventional observation methods, it would be impossible to detect minute fluff with sufficient sensitivity as envisioned in this embodiment, and consequently, it would be difficult to come up with the idea of ​​controlling the deduction rate to the numerical range envisioned in this embodiment. The method for calculating the "deduction rate (%)" will be described in detail in the examples.

[0020] The overall fluffiness includes fluffing of 200-1000 μm due to filament breakage, which can be observed on the cloth surface using an optical microscope. As in this embodiment, the cloth surface is easily observed by irradiating it with white LED light along the surface.

[0021] The glass cloth of this embodiment preferably has the thickness described later. Furthermore, the glass yarn used to obtain the glass cloth of this embodiment preferably has the configuration described later.

[0022] (Dielectric constant of glass cloth) The dielectric constant of the glass cloth 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 of the glass cloth can be measured by the cavity resonance method. In this specification, unless otherwise specified, the dielectric constant of the glass cloth refers to the dielectric constant at a frequency of 10 GHz.

[0023] [Glass thread] A second embodiment of the present invention is a glass fiber.

[0024] The glass yarn of the second embodiment is (i)TEX is 1 to 13, (ii) The breaking strength is 0.50 to 0.80 N / tex, and (iii) The number of filaments that have slipped out at a rate of more than twice the average thread width when measured over 180m (hereinafter, "the number of filaments that have slipped out at a rate of more than twice the average thread width when measured over 180m" will also be simply referred to as "the number of slipped filaments") is 3 or less.

[0025] Glass cloth manufactured using low-dielectric glass yarn exhibited greater variability in quality compared to conventional E-glass cloth. Therefore, it became clear that obtaining consistently high-quality low-dielectric glass cloth was difficult. A detailed examination of relatively inferior glass cloths revealed that those manufactured from low-dielectric glass yarn with a number of slipped filaments outside a specific range exhibited a significant number of "band-shaped fluff defects," where fluff was densely concentrated in a band-like pattern along the length. In contrast, this practical application is based on the finding that using low-dielectric glass yarn with filament shedding within a specific range can reduce this defect in low-dielectric glass cloth. While not theoretically bound, this reasoning suggests that glass yarn with a number of slipped filaments greater than three is more prone to increased filament shedding or filament breakage during the weaving process, particularly when encountering interference with loom components such as loop guides after being unwound from the bobbin.

[0026] In particular, the weft yarn is transported with a ballooning motion along the yarn path from the bobbin until it is ejected. Therefore, the areas where the filaments slip off are susceptible to shear stress and are prone to breaking, and the broken filament pieces tend to entangle due to their swirling motion, growing into coarse fluff. While a faster weft yarn insertion speed is preferable to increase productivity, it is thought that the faster the weft yarn transport speed, the greater the likelihood of filament shedding or breakage.

[0027] The glass yarn made from E-glass, which has been used until now, has a higher density and greater strength than low-dielectric glass yarn. As a result, the transport of the glass yarn is stable, and the degree of interference with loom components is small, and therefore the damage sustained when interference occurs is limited. On the other hand, with the lighter and weaker low-dielectric glass yarn, the vibration tends to be greater due to tension fluctuations when the glass yarn is transported. As a result, interference with loom components is more likely to occur, and when interference occurs, the yarn is more susceptible to greater damage. Therefore, it is thought that this is likely to increase the rate at which filaments fall off or break.

[0028] Furthermore, in glass yarns where filament shedding exceeds a specific range, the shedding areas are more prone to movement when subjected to physical loads such as high-pressure spray water during the fiber opening process. As a result, the shedding areas are more susceptible to loads such as interference with the glass cloth transport members, and it is thought that fuzzing due to filament breakage or fluffing at the broken areas is likely to occur starting from the shedding areas. While a strong fiber opening force is preferable for improving the in-plane uniformity and impregnation of the glass cloth, it is thought that the stronger the fiber opening force, the more likely fuzzing defects due to filament breakage or coarse fuzzing defects due to filament entanglement will occur.

[0029] Furthermore, low-dielectric glass yarns, which have lower density and weaker strength than E-glass, experience a significant decrease in glass strength during the heat cleaning process. Therefore, when performing the fiber opening process after the heat cleaning, they are subjected to strong physical stress from high-pressure water sprays, making them more susceptible to fraying due to filament breakage or fluffing of broken filaments. These effects are thought to be reflected in the quality of the glass cloth.

[0030] On the other hand, by using the glass yarn of this embodiment, even when using relatively light and weak glass yarn with low dielectric strength, the damage sustained when the glass yarn is unraveled in the weaving process and passes through loom components such as loop guides can be reduced. Furthermore, the use of the glass yarn of this embodiment can also reduce the degree to which the detached portion interferes with the conveying component or the damage sustained when such interference occurs during the fiber opening process. As a result, by using the glass yarn of this embodiment, the generation of fluff caused by filament breakage in the weaving and fiber opening processes can be suppressed, and a high-quality, uniform glass cloth can be obtained. In addition, using the above-mentioned glass yarn tends to increase the weaving speed (glass yarn beading speed) and / or the fiber opening force in the fiber opening process, which is preferable.

[0031] When using the glass yarn of this embodiment, defects such as the generation of fuzz when the glass yarn (e.g., warp thread) is rubbed against thread guides during the process of unwinding the bobbin yarn in the creel can be prevented, which is preferable as it tends to result in high-quality and stable production. Furthermore, using the above-mentioned glass yarn tends to increase the warping speed, which is also preferable.

[0032] (Tex made from glass fiber) The TEX of the glass yarn is 1 to 13, preferably 1.5 to 12, more preferably 2.0 to 11, even more preferably 2.5 to 10, or 1 to 7. If the TEX of the glass yarn is 13 or less, the strength of the glass yarn is weak, which may lead to a tendency for fluffing defects to occur due to interference with loom components such as loop guides when the glass yarn is unraveled and passes through the loom components, and interference with glass cloth transport components in the fiber opening process. On the other hand, by adjusting the degree of filament shedding to within the specific range of this embodiment, the degree of interference or the damage received during interference can be reduced, and as a result, high-quality glass cloth can be stably obtained. When the TEX of the glass yarn is 1 or more, and the degree of filament shedding is within the specific range of this embodiment, filament breakage can be suppressed when the glass yarn is unraveled and passes through loom components such as loop guides in the weaving process, and when it interferes with glass cloth transport components in the fiber opening process.

[0033] (Breaking strength of glass fiber) The breaking strength of glass yarn is 0.50 to 0.80 N / tex. The preferred range of breaking strength is 0.53 to 0.79 N / tex, the more preferred range is 0.57 to 0.78 N / tex, and the even more preferred range is 0.60 to 0.77 N / tex. If the breaking strength of glass yarn is above the lower limit above, the filaments are less likely to break and less likely to generate fluff when subjected to shear stress due to interference with loom components such as loop guides when the glass yarn is unwound and passes through loom components during the weaving process, and when it is subjected to interference with glass cloth transport components during the fiber opening process. On the other hand, if the breaking strength of glass yarn is below the upper limit above, the vibration or ballooning motion of the yarn during the yarn transport process from when the glass yarn is unwound from the bobbin until it is ejected tends to be suppressed, and as a result, increased filament shedding or fluffing defects due to filament breakage are less likely to occur. This is presumed to be an effect based on the flexibility of glass yarn.

[0034] (Number of slipped filaments in glass fiber) The glass filament has three or fewer sliding filaments. The preferred range for the number of sliding filaments is two or fewer, more preferably one or fewer, and even more preferably zero.

[0035] The "180m" mentioned above refers to, 1) The length of a glass thread, starting from one end (one end or the other) in the longitudinal direction; 2) Length at any point excluding the ends; Either one is fine. A specific example of the above 2) is: 2-1) Length set starting from a point 2 to 6 m (for example, 5 m) from the end in the longitudinal direction. One example is 2-1), which allows for accurate measurement of the number of slipped filaments in accordance with the spirit of the present invention, without being affected by "fraying" that tends to occur at the ends of the glass thread.

[0036] If the glass thread is wound onto a bobbin, then "180m" means, 3) Length including at least a portion of the outermost or innermost circumference of the bobbin; 4) Length at any point excluding the outermost and innermost circumferences; Either one is fine. As a specific example of the above 4), from the perspective of ease of observation, 4-1) The length set starting from the beginning of the second lap, with the outermost perimeter being considered the first lap; 4-2) The length set starting from the beginning of the second rotation, with the innermost circumference being considered the first rotation; However, the following can be cited. 4-3) Length set at any point other than the starting point mentioned above. That's fine.

[0037] When a glass yarn with a length of 10,000 m or more is subjected to measurement in the longitudinal direction of 180 m at five different locations, the number of slipped filaments is preferably 3 or less, more preferably 2 or less, even more preferably 1 or less, and most preferably 0 in each of the five measurement ranges.

[0038] Furthermore, when a glass yarn having a length of 50,000 m or more is subjected to a measurement range of 180 m in the longitudinal direction at seven different locations, the number of slipped filaments is preferably 3 or less, more preferably 2 or less, even more preferably 1 or less, and most preferably 0 in each of the seven measurement ranges.

[0039] Furthermore, when a glass yarn having a length of 100,000 m or more is subjected to a measurement range of 180 m in the length direction at 10 different locations, the number of slipped filaments is preferably 3 or less, more preferably 2 or less, even more preferably 1 or less, and most preferably 0 in each of the 10 measurement ranges.

[0040] When measuring the number of slipped filaments, the glass yarn transport speed may be increased. Similar to weft yarn ejection in the weaving process, the glass yarn should be unwound from the bobbin using air and transported while measurement is performed (at this time, appropriate yarn guides should be provided to prevent the ejected glass yarn from becoming unruly). These methods are possible. However, the measurement of the number of slipped filaments is performed in accordance with the method described in the examples.

[0041] Because the number of slipped filaments is below the above range and the breaking strength is within the above range, it is difficult to increase filament shedding, filament breakage, or the generation of coarse fluff due to entanglement of broken filaments during the transport process from unwinding the glass yarn from the bobbin to ejection. As a result, high-quality glass cloth with fewer areas of dense fluff can be stably obtained. This is presumed to be because the degree and frequency of filament slippage are small and within a certain range, so the degree to which the slipped areas interfere with loom components such as loop guides, or the resistance due to interference, is reduced, and thus damage due to interference with loom components can be kept to a minimum.

[0042] In particular, the weft threads are easily cut, as described above, and the cut filament pieces tend to entangle due to ballooning motion. On the other hand, it is presumed that by adjusting the number of detached filaments within the above range, filament cutting or entanglement of cut filaments can be suppressed. Furthermore, it is presumed that because the degree and frequency of filament slippage are small and within a certain range, the degree of interference with the glass cloth conveying member during the fiber opening process, or the resistance due to interference, is reduced, thereby minimizing damage caused by interference with the conveying member.

[0043] The number of sliding filaments can be adjusted by the following methods, either individually or in combination: A method for designing the arrangement of bushing nozzles in the spinning process of glass fiber manufacturing, such that the distance from multiple bushing nozzles to the convergence point is equal when converging filaments extruded from multiple bushing nozzles into a single yarn bundle; A method for adjusting the nozzle shape of the bushing nozzle according to the difference in distance from the bushing nozzle to the focal point; • A method for adjusting the temperature of the bushing nozzle according to the difference in distance from the bushing nozzle to the focal point; • A method for adjusting the cooling temperature in the spinning process of glass fiber manufacturing; • How to adjust the cake winding tension; • How to adjust the cake rolling speed; • How to adjust the traverse when rolling up the cake; A method for adjusting the cake winding method and aging conditions in the aging process of glass fiber manufacturing, so that the moisture content and sizing agent adhesion of the glass fiber become more uniform throughout the entire length of the glass fiber; • A method for adjusting the shape and weight of a traveler in the twisting process of glass yarn manufacturing to reduce the stress on the glass yarn when it is bent; A method for adjusting the variation in the number of twists per unit length to a specific range; A method for adjusting the tension fluctuations of the glass thread as it is unwound from the cake and wound onto the bobbin; · Method for adjusting ballooning during twisting; and · Method for adjusting the winding angle of glass yarn onto a bobbin.

[0044] (Density of glass yarn) The density of the glass yarn is preferably 2.2 g / cm 3 or more and 2.5 g / cm 3 less, more preferably 2.2 g / cm 3 or more and 2.45 g / cm 3 less, even more preferably 2.2 g / cm 3 or more and 2.40 g / cm 3 or less, still more preferably 2.25 g / cm 3 or more and 2.4 g / cm 3 or less.

[0045] When the density of the glass yarn is less than 2.5 g / cm 3 during the conveying process until the glass yarn is unwound from the bobbin and ejected, the vibration or ballooning movement in the direction perpendicular to the conveying direction tends to increase, and there may be a tendency for hairiness defects to occur due to interference with loom members. However, by adjusting the number of slippage filaments within the specific range according to this embodiment, the generation of hairiness due to interference with loom members can be suppressed, and thus a high-quality glass cloth can be stably obtained.

[0046] Also, when the density of the glass yarn is less than 2.5 g / cm 3 during the open fiber process when receiving physical loads such as high-pressure water spray pressure, the relaxation of the glass cloth becomes large, the glass cloth tends to interfere with the conveying member, and there may be a tendency for hairiness defects to occur due to interference with the conveying member. However, by adjusting the number of slippage filaments within the specific range in this embodiment, the generation of hairiness due to interference with the conveying member can be suppressed, and thus a high-quality glass cloth can be stably obtained.

[0047] On the other hand, when the density of the glass yarn is 2.2 g / cm 3 or more, the conveying path of the glass yarn can be stabilized. Also, when the density of the glass yarn is 2.2 g / cm 3As a result of the above, the slack in the glass cloth can be reduced. The density of the glass threads is 1 cm 3 It can be determined as the density of the solidified glass.

[0048] (Filament and diameter) Glass filaments are obtained by bundling multiple filaments together and twisting them as needed. In this case, glass filaments are classified as multi-glass filaments, while the filaments contained within the glass filaments (glass filaments) are classified as mono-glass filaments. Here, "filament slippage" refers not only to slippage of a single monoglass filament, slippage of several monoglass filaments, but also to filaments that have broken. The number of slipped filaments can be measured by the method described in the examples.

[0049] The glass yarn is preferably a glass yarn made by bundling 40 to 240 monoglass filaments with an average diameter of 3.5 to 5.5 mm, or a glass yarn with 30 to 120 monoglass filaments. By using glass yarn with an average diameter and number of filaments within the above range, it is easy to manufacture glass cloth with thicknesses equivalent to conventional E glass cloths of 1000, 1017, 1015, 1012, 1027, 1024, 1020, 1030, 1037, 1035, 106, 1067, and 1078 (IPC standard (IPC-4412B): Style 1000, 1017, 1015, 1012, 1027, 1024, 1020, 1030, 1037, 1035, 106, 1067, 1078).

[0050] (Elastic modulus of glass fiber) The elastic modulus of the glass yarn is preferably 50 to 70 GPa, more preferably 50 to 63 GPa, and even more preferably 53 to 63 GPa. An elastic modulus of 50 GPa or higher improves the rigidity of the glass yarn, making it less prone to fuzzing during the manufacturing process. An elastic modulus of 70 GPa or lower improves the brittleness resistance of the glass yarn, making it less prone to fuzzing during the manufacturing process. Furthermore, an elastic modulus within the above range gives the glass yarn moderate flexibility, making it less prone to filament breakage when mechanical load is applied, and less prone to fuzzing and weaving defects.

[0051] (Composition of glass fiber components) The constituent elements of glass fibers include silicon (Si), boron (B), aluminum (Al), calcium (Ca), magnesium (Mg), phosphorus (P), sodium (Na), potassium (K), titanium (Ti), zinc (Zn), iron (Fe), and fluorine (F).

[0052] The Si content of the glass yarn is preferably 40-60% by mass, more preferably 45-55% by mass, even more preferably 47-53% by mass, and even more preferably 48-52% by mass, in terms of SiO2.

[0053] Si is a component that forms the skeletal structure of glass fibers, and a Si content of 40% by mass or more tends to improve the strength of the glass fibers. As a result, the breakage of the glass cloth tends to be suppressed in the manufacturing process of glass cloth and in subsequent processes such as the manufacturing of prepregs using glass cloth. In addition, a Si content of 40% by mass or more tends to lower the dielectric constant of the glass cloth. On the other hand, a Si content of 60% by mass or less tends to lower the viscosity during melting in the filament manufacturing process, resulting in the acquisition of glass fibers with a more homogeneous glass composition. Therefore, the resulting filament is less likely to have areas that are easily devitrified or areas where air bubbles are difficult to escape, thus reducing the occurrence of locally weak areas in the filament, and as a result, the glass cloth made from the glass fibers obtained using this filament is less likely to break. The Si content can be adjusted according to the amount of raw materials used in filament production.

[0054] The B content of the glass yarn is preferably 15-40% by mass, more preferably 17-30% by mass, or 20-40% by mass, even more preferably 18-28% by mass, even more preferably 19-26% by mass, even more preferably 20-25% by mass, and most preferably 20.5-24% by mass, based on B2O3.

[0055] A B content of 15% by mass or more tends to lower the dielectric constant. Furthermore, a B content of 15% by mass or more improves the brittleness resistance of the glass cloth, imparts appropriate flexibility and suppleness, and tends to reduce fuzzing when the glass yarn comes into contact with loom components such as yarn guides and reeds. On the other hand, to maintain the strength of the glass yarn, a B content of 40% by mass or less is preferable. Additionally, a B content of 40% by mass or less improves moisture resistance. The B content can be adjusted according to the amount of raw material used in filament production. If conditions, usage, or content may fluctuate during filament production, the amount of raw material prepared can be adjusted in advance to account for these fluctuations.

[0056] The Al content of the glass filament is preferably 11-18% by mass, more preferably 11-16% by mass, and even more preferably 12-16% by mass, in terms of aluminum oxide (Al2O3). Having an Al content within this range tends to improve electrical properties and strength. The Al content can be adjusted according to the amount of raw material used in filament production.

[0057] The Ca content of the glass filament is preferably 5 to 10% by mass, preferably 5 to 9% by mass, and more preferably 5 to 8.5% by mass, in terms of calcium oxide (CaO). A Ca content of 5% by mass or more tends to reduce the viscosity during melting in the filament manufacturing process, resulting in glass fibers with a more homogeneous glass composition. Furthermore, a Ca content of 10% by mass or less tends to improve the dielectric constant. The Ca content can be adjusted according to the amount of raw materials used in filament production.

[0058] Glass filaments may exhibit superior properties by containing predetermined amounts of Mg, P, Na, K, Ti, Zn, Fe, and F. These elements can be adjusted according to the amount of raw materials used in filament production.

[0059] Each of the above content levels can be measured by ICP emission spectrometry. Specifically, the Si and B content can be obtained by dissolving the weighed glass cloth sample in sodium carbonate, then dissolving it in dilute nitric acid to a fixed volume, and measuring the resulting sample by ICP emission spectrometry. The Fe content can be obtained by dissolving the weighed glass cloth sample in an alkaline solution to a fixed volume, and measuring the resulting sample by ICP emission spectrometry. Furthermore, the Al, Ca, and Mg content can be obtained by thermally decomposing the weighed glass cloth sample with sulfuric acid, nitric acid, and hydrogen fluoride, then dissolving it in dilute nitric acid to a fixed volume, and measuring the resulting sample by ICP emission spectrometry. The ICP emission spectrometer used is the PS3520VDD II manufactured by Hitachi High-Tech Science Corporation.

[0060] (Dielectric constant of glass fiber) The dielectric constant of the glass fiber 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 of the glass fiber can be measured, for example, by the cavity resonance method. In this specification, unless otherwise specified, the dielectric constant of the glass fiber refers to the dielectric constant at a frequency of 10 GHz.

[0061] (Twist spacing length and twist spacing length difference index of glass yarn) The twist spacing length of the glass yarn is preferably 1.8 to 10.0 cm, more preferably 1.9 to 9.9 cm, even more preferably 1.95 to 4.0 cm, and most preferably 2.0 to 3.5 cm. The minimum twist spacing length is preferably 1.8 cm, more preferably 1.9 cm, even more preferably 1.95 cm, and most preferably 2.0 cm. The maximum twist spacing length is preferably 10.0 cm, more preferably 9.9 cm, even more preferably 4.0 cm, and most preferably 3.5 cm.

[0062] Furthermore, the value obtained by dividing the difference between the maximum and minimum twist spacing lengths of the glass yarn by the average twist spacing length (twist spacing length difference index) is preferably 0.7 or less, more preferably 0.6 or less, even more preferably 0.5 or less, and most preferably 0.4 or less, and may also be greater than 0. When the twist spacing length and / or twist spacing length difference index of the glass yarn are within the above numerical range, the number of slipped filaments evaluated in the outer layer of the bobbin tends to be 3 or less when the glass yarn is wound on a bobbin, and / or the number of slipped filaments tends to be small over the entire length of the bobbin. Although we do not wish to be constrained by theory, the following three reasons can be considered for the decrease in the number of slipped filaments: (i) If the twist spacing length is longer than the lower limit, the torsional shear stress is kept low, making filament slippage less likely; (ii) If the twist spacing length is shorter than the upper limit, the restraining force between the filaments constituting the glass yarn is increased, making it less likely for the filaments to slip off; (iii) When the twist spacing length difference index is smaller than the upper limit, the variation in the twist angle in the length direction of the glass yarn is kept small, making it less likely for the filament to slip off. The standard deviation of the number of twists in the glass yarn is preferably 0.05 to 0.20, and more preferably 0.09 to 0.18.

[0063] [Method for manufacturing glass cloth] A third embodiment of the present invention is a method for manufacturing glass cloth.

[0064] This embodiment is a method for manufacturing glass cloth, which includes a step of weaving using glass yarn containing multiple filaments as warp and weft threads. The glass thread used is as described above. (i)TEX is 1 to 13, (ii) The breaking strength is 0.50 to 0.80 N / tex, and (iii) Number of slipped filaments (The number of slipped filaments is 3 or less, and is 2 times or more the average thread width when measured over 180m.)

[0065] Such a manufacturing method specifically includes a glass yarn preparation step of adjusting the glass yarn so that the number of slipped filaments is less than or equal to a specific number, a weaving step of weaving the prepared glass yarn to obtain glass cloth, and a fiber opening step of opening the glass yarn of the glass cloth. The manufacturing method of glass cloth may optionally include a desizing step of removing sizing agents adhering to the glass yarn of the glass cloth and a surface treatment step of using a silane coupling agent. The following provides a more detailed explanation of each step in the manufacturing method of glass cloth.

[0066] (Glass thread adjustment process) The glass yarn preparation process is a process of preparing glass yarn so that the number of slipped filaments is 3 or less. More specifically, in the glass yarn preparation process, if the number of slipped filaments is within the above range, the glass yarn is used in the subsequent weaving process; if it is outside the range, the use of the glass yarn is prohibited.

[0067] Methods for measuring the number of slipped filaments include observing the thread width and the number of slipped filaments using a light projection type displacement meter such as a laser or LED light while transporting the glass thread; and observing the thread width and the number of slipped filaments while transporting the glass thread and observing the shape of the glass thread with an image.

[0068] (Weaving process) The weaving process involves weaving glass yarn to obtain glass cloth. Examples of weaving structures for glass cloth include plain weave, twill weave, satin weave, and twill weave. Among these, the plain weave structure is preferred.

[0069] In one example of the weaving process in the manufacturing method of this embodiment, the parallel warp threads are opened at the top and bottom using an air jet loom system, and weaving can be performed by feeding yarn supplied from a weft storage device as weft yarn through these openings by a jet stream from a nozzle.

[0070] In this weaving process, in the glass yarn ejection process, in which the glass yarn that will become the weft is wound from the bobbin and ejected through a storage device, The glass yarn is transported while moving in a direction different from the direction of travel, such as ballooning motion, and while interfering with loom components such as yarn guides; or, Because the weft yarn is ejected and stopped repeatedly in units of one weft thread length, it is transported while experiencing tension fluctuations and interference with loom components such as yarn guides; Weft yarns with a high number of slipped filaments are difficult to minimize damage caused by the above interference, and the resulting glass cloth may have fuzz or weaving defects.

[0071] In contrast, in this embodiment, by using glass yarn in which the number of slipped filaments is within a specific range, the occurrence of fluff or weaving defects when weaving the weft can be suppressed, thereby improving the in-plane uniformity and lot-to-lot uniformity of the glass cloth quality. The weaving method is not limited to the air jet loom method, but may also be the water jet loom method or the shuttle method.

[0072] The density of the warp and weft threads constituting the glass cloth is preferably 30 to 120 threads / 25 mm, more preferably 40 to 110 threads / 25 mm, and even more preferably 45 to 105 threads / 25 mm. The density of the warp threads can be controlled by adjusting the spacing between the parallel warp threads, and the density of the weft threads can be controlled by the number of weft threads ejected per unit time from the nozzle and the flow speed of the warp threads.

[0073] (Opening process) The fiber opening process is the process of separating the glass fibers of glass cloth. Examples of fiber opening methods include spray water (high-pressure water opening), vibro-washer, ultrasonic water, and mangle.

[0074] The thickness of the glass cloth finally obtained after the fiber opening process is preferably 5 to 60 μm, more preferably 7 to 55 μm, and even more preferably 9 to 50 μm or 10 to 50 μm. A glass cloth thickness within the above range tends to yield a thin yet relatively strong glass cloth. The fabric weight (basis weight) of the glass cloth finally obtained after the fiber opening process is preferably 5 to 55 g / m². 2 , more comfortably 6-50g / m 2 More preferably 7-48 g / m 2 That is the case.

[0075] (Desizing process) The de-sizing process is the process of removing the sizing agent adhering to the glass fibers of the glass cloth. One method of de-sizing is to remove the sizing agent by heating.

[0076] (Surface treatment process) The surface treatment process involves surface treatment of the glass cloth with a silane coupling agent. The surface treatment method includes contacting the glass cloth with a surface treatment agent containing the silane coupling agent and then drying it. Contact with the glass cloth can be achieved by impregnating the glass cloth with the surface treatment agent; or by applying the surface treatment agent to the glass cloth using a roll coater, die coater, or gravure coater. The drying method for the surface treatment agent is not particularly limited, but examples include hot air drying and drying using electromagnetic waves.

[0077] [Prepreg] The prepreg comprises a glass cloth obtained as described above and a matrix resin composition impregnated into the glass cloth. The prepreg having the glass cloth exhibits less variation in quality and a higher yield of the final product.

[0078] Prepregs can be manufactured according to conventional methods. For example, they can be manufactured by impregnating glass cloth with a varnish in which a matrix resin such as epoxy resin is diluted with an organic solvent, then evaporating the organic solvent in a drying oven to cure the thermosetting resin to the B-stage (semi-cured) state.

[0079] Examples of matrix resin compositions include, in addition to the epoxy resins mentioned above, thermosetting resins such as bismaleimide resins, cyanate ester resins, unsaturated polyester resins, polyimide resins, BT resins, and functionalized polyphenylene ether resins; thermoplastic resins such as polyphenylene ether resins, polyetherimide resins, all-aromatic polyester liquid crystal polymers (LCPs), polybutadiene, and fluororesins; and mixed resins thereof. From the viewpoint of improving dielectric properties, heat resistance, solvent resistance, and press moldability, a resin obtained by modifying a thermoplastic resin with a thermosetting resin may be used as the matrix resin composition.

[0080] Furthermore, the matrix resin composition may contain inorganic fillers such as silica and aluminum hydroxide; flame retardants such as bromine-based, phosphorus-based, or metal hydroxide-based agents; other silane coupling agents; heat stabilizers; antistatic agents; ultraviolet absorbers; pigments; colorants; lubricants, etc.

[0081] [Printed wiring board] It is preferable that the printed circuit board includes the above-mentioned prepreg. Printed circuit boards that include the above-mentioned prepreg have less variation in quality and a higher yield of the final product. Furthermore, printed circuit boards that include the above-mentioned prepreg have excellent dielectric properties and excellent moisture resistance, so they can also have the effect of being less affected by the operating environment, especially in high humidity environments, where the dielectric constant fluctuates less. [Examples]

[0082] The present invention will be described more specifically below using examples and comparative examples.

[0083] [Physical properties of glass yarn and glass cloth] The physical properties of the glass yarn and glass cloth, specifically the thickness of the glass cloth, the average diameter of the filaments constituting the glass yarn, the TEX of the glass yarn, the breaking strength (tensile strength) of the glass yarn, and the weave density (pile density) of the warp and weft threads, were measured in accordance with JIS R3420.

[0084] [Twist spacing length, twist spacing length difference index] Using a twist analyzer (manufactured by Technos Co., Ltd.), the number of twists in a 50cm length of glass yarn was measured. The length per twist interval was calculated by dividing the measured length of 50cm by the obtained number of twists. The number of twists per 50cm was repeatedly measured at 30 points using this method, and the length per twist interval was calculated for each of the 30 points of data. The length per twist interval was then averaged to determine the length of the twist interval.

[0085] Furthermore, using the average, maximum, and minimum values ​​of the 30 twist spacing length data points obtained, the twist spacing length difference index was calculated using the following formula (1) as the ratio of the difference between the maximum and minimum twist spacing lengths to the average twist spacing length. Twist spacing length difference index = {(Maximum twist spacing length - Minimum twist spacing length) / Average twist spacing length} × 100 ... (1)

[0086] [Standard deviation of the number of strands] Using a twist analyzer (manufactured by Technos Co., Ltd.), the number of twists in a 50cm length of glass yarn was measured and converted to the number of twists per 25mm. The number of twists per 25mm was repeatedly measured at 30 points using this method, and the standard deviation of the 30 obtained twist count data points was calculated.

[0087] [Elastic modulus] The elastic modulus of the glass fiber was measured using the pulsed echo overlap method, with glass bulk obtained by melting and cooling the glass fiber as the test specimen.

[0088] [Number of sliding filaments] While transporting glass yarn at a speed of 1 m / min, the yarn width was continuously measured using an LED camera-type dimension measuring instrument (HIGH ACCURACY CMOS MICROMETER LS-9006MR / Keyence Corporation) while observing the projected shape of the glass yarn on a monitor. The yarn width of 180 m of glass yarn was measured, and the average value of the yarn width was calculated from the obtained yarn width data. In addition, the number of cases in which filament slippage was observed at a rate of more than twice the yarn width from the center of the yarn width was counted, and the total of these counts was defined as the "number of slipped filaments," i.e., "the number of filaments that slipped at a rate of more than twice the average yarn width over 180 m of measurement."

[0089] Here, the yarn width measurement using an LED camera type dimensional measuring instrument was performed under conditions that yielded 1934 measurement points per meter. If an error occurred due to the LED not being in focus (a value of -9999 was displayed), the measurement was deleted, and the average yarn width and / or the number of slipped filaments were calculated.

[0090] The tension acting on the glass yarn during transport was measured using a tension meter (SCHMIDT Conrol instruments ETPB-100-C0585) and was between 0.12 and 0.18 N.

[0091] [Bobbin visual inspection (fuzz inspection)] The bobbin wound with glass thread was visually inspected, and the number of detected fuzzy fibers was counted. This inspection was performed 50 times, and the average number of fuzzy fibers was calculated.

[0092] [Fuzziness test of glass fiber by applying a load to the glass fiber] Using a fluff inspection device manufactured by NIHON KAGAKU ENG, glass yarn was transported at a speed of 1 m / min and passed through a model reed with a reed spacing of 0.35 mm, which made 450 reciprocations per minute, and then subjected to tacking. The number of fluff generated per 180 m was then counted using a sensor. Similarly, the number of fluff generated per 180 m was counted using a sensor when the reciprocating speed of the model reed was set to 100 reciprocations / min.

[0093] [Evaluation: Fiber quality of the glass cloth] The effect of glass yarn quality (e.g., number of slipped filaments) on the fluff quality of glass cloth was investigated. Standard conditions for glass cloth production were set to a loom rotation speed of 450 rpm, and fiber opening treatment was performed using a high-pressure water spray. Furthermore, the loom rotation speed was increased (550, 600 rpm) to improve productivity, and the intensity of the high-pressure water spray was increased to improve properties.

[0094] The fluff quality of the glass cloth obtained in the examples, comparative examples, and reference examples was evaluated by visual inspection. Using a glass cloth inspection machine, the fluff quality of the glass cloth was evaluated visually while the glass cloth was transported at a speed of 10 m / min. Here, conventional visual inspections observe fluff and weaving defects by shining halogen lamp light perpendicular to the glass cloth and observing the areas where the light is reflected. However, in order to sensitively observe filament breakage fluff of less than 1 mm in length, a visual inspection was performed by shining white LED light parallel to the glass cloth surface from the edge side of the glass cloth. Fuff was scattered throughout the entire surface of the inspection plate-shaped glass cloth, and therefore, the state of fluff occurrence that was observed as shining across the entire surface of the glass cloth was defined as a full-surface fluff defect. When the fluffing in the full-surface fluffing areas was observed with an optical microscope, a large amount of fluffing due to filament breakage of approximately 200 μm to 1000 μm was found.

[0095] For a measurement length of 500m, if lint is present throughout a 1m area in the length direction of the glass cloth, it is counted as 1 defect, and the following formula is used: Deduction rate (%) = (Total number of defects / 500) × 100 The penalty rate was calculated accordingly.

[0096] [Evaluation: Evaluation of the impregnation properties of glass cloth] Under conditions of 23±2℃, a bisphenol A type epoxy resin was dissolved in benzyl alcohol to prepare a varnish for evaluating impregnation with a viscosity of 230±5 mPa·s. Next, glass cloth test pieces were immersed in the impregnation evaluation varnish, and while irradiating with light from the side, the impregnation of the varnish into the glass cloth was observed using an optical microscope. The number of voids (unimpregnated areas of the impregnation evaluation varnish) was counted 5 minutes after immersion of the glass cloth test piece in the impregnation evaluation varnish. At this time, the field of view of the glass cloth observed with the optical microscope was approximately 6.5 mm in the warp direction and approximately 9 mm in the weft direction.

[0097] [Examples and Comparative Examples; Glass Yarn] [Test Example 1] Glass threads A-N (low dielectric glass thread, density 2.3 g / cm³) are wound on a bobbin. 3 Elastic modulus 61 GPa), O~Q (low dielectric glass yarn, density 2.3 g / cm³) 3 Elastic modulus 56 GPa), R(E glass yarn, density 2.6 g / cm³ 3 The outermost layer of glass yarn from a bobbin with an elastic modulus of 74 GPa was unwound, and the number of slipped filaments was measured starting from point T0, which was 5 m in the length direction from the end.

[0098] [Test Example 2] Next, the point where 500m of glass yarn is further unraveled from the bobbin, that is, the point 500m in the length direction from the starting point T0, is called starting point T 500 The number of slipped filaments was measured.

[0099] [Test Example 3] Following the above examples 1 and 2, the glass thread was further unraveled from the bobbin. Starting point T0 is 1,000m in the length direction from the starting point T. 1,000 as; Starting from the above starting point T0, the point 2,000m in the length direction is the starting point T 2,000 as; Starting from the above starting point T0, the point 5,000m in the length direction is the starting point T 5,000 as; Starting from the above starting point T0, the point 7,000m in the length direction is the starting point T 7,000 as; Starting from the above starting point T0, the point 9,000m in the length direction is the starting point T 9,000 as; Starting point T0 is 10,000m in the length direction from the above starting point T. 10,000 as; Starting point T0 is 20,000m in the length direction from the starting point T. 20,000 as; Starting point T0 is 30,000m in the length direction from the above starting point T. 30,000 as; Starting point T0 is 40,000m in the length direction from the above starting point T. 40,000 as; Starting point T0 is 50,000m in the length direction from the above starting point T. 50,000as; Starting point T0 is 60,000m in the length direction from the starting point T. 60,000 as; Starting point T0 is 70,000m in the length direction from the above starting point T. 70,000 as; Starting point T0 is 80,000m in the length direction from the above starting point T. 80,000 as; Starting point T0 is 100,000m in the length direction from the above starting point T. 100,000 as; Starting from the above starting point T0, the point 120,000m in the length direction is the starting point T 120,000 as; The number of slipped filaments was measured. The results are shown in Table 1.

[0100] [Table 1-1]

[0101] [Table 1-2]

[0102] Examples of glass yarns A-C, G, H, J, K, O, and P, which have a small twist spacing length difference index and are uniformly and loosely twisted, had a number of slipped filaments of 3 or less evaluated in the outer layer of the bobbin. And then, starting point T0; starting point T 500 ;Origin T 1,000 ;Origin T 2,000 ;Origin T 5,000 ;Origin T 7,000 ;Origin T 9,000 Regardless of which starting point was used for measurement, the number of slipped filaments was 3 or less. This confirmed that when a glass yarn with a length of 10,000 m or more was measured at five different locations, each with a measurement range of 180 m in the length direction, the number of slipped filaments was 3 or less in each of the five measurement ranges.

[0103] Even when using glass threads with a length of 50,000m or more, according to the same principle as above, when a measurement range of 180m in the length direction was selected at seven different locations, it was confirmed that the number of slipped filaments was 3 or less in each of the seven measurement ranges.

[0104] Even when using glass threads with a length of 100,000m or more, according to the same principle as above, when a measurement range of 180m in the length direction was selected at 10 different locations, it was confirmed that the number of slipped filaments was 3 or less in each of the 10 measurement ranges.

[0105] On the other hand, the comparative glass yarns D~F, I, L~N, Q, R, which had a large twist spacing length difference index, had four or more slipped filaments within the predetermined measurement range.

[0106] [Example 1] Using the low-dielectric glass yarns listed in the table below (TEX 4.9, 100 filaments, elastic modulus 61 GPa, glass composition: 51.2 mass% in SiO2 equivalent, 14.3 mass% in Al2O3 equivalent, 8.1 mass% in CaO equivalent, 0.3 mass% in MgO equivalent, 23.3 mass% in B2O3 equivalent, 0.1 mass% in P2O3 equivalent) for both warp and weft threads, a glass cloth fabric with a warp weave density of 65 threads / 25 mm and a weft weave density of 67 threads / 25 mm was obtained under the conditions of a loom rotation speed of 450 rpm (weft thread insertion speed of 450 threads / min) in an air jet room. As shown in the table under the item "Number of slipped filaments measured from starting point T0", in Example 1, a glass yarn was used in which the number of slipped filaments was 0, and the number of slipped filaments was 2 times or more the average yarn width when measured 180m from the starting point T0.

[0107] Next, the glass cloth is de-sticked by heating, and the water pressure is set to 5.0 ± 0.1 kg / cm². 2 High-pressure water fiber splitting was performed using a spray adjusted to the specified pressure, followed by surface treatment with a silane coupling agent to produce a glass cloth with a thickness of 29 μm.

[0108] [Example 2] A glass cloth with a thickness of 29 μm was prepared in the same manner as in Example 1, except that the low-dielectric glass yarn listed in the table below (TEX 4.9, 100 filaments, elastic modulus 61 GPa, glass composition: 51.2 mass% in terms of SiO2, 14.3 mass% in terms of Al2O3, 8.1 mass% in terms of CaO, 0.3 mass% in terms of MgO, 23.3 mass% in terms of B2O3, 0.1 mass% in terms of P2O3) was used.

[0109] [Example 3] A glass cloth with a thickness of 29 μm was prepared in the same manner as in Example 1, except that the low-dielectric glass yarn listed in the table below (TEX 4.9, 100 filaments, elastic modulus 61 GPa, glass composition: 51.2 mass% in terms of SiO2, 14.3 mass% in terms of Al2O3, 8.1 mass% in terms of CaO, 0.3 mass% in terms of MgO, 23.3 mass% in terms of B2O3, 0.1 mass% in terms of P2O3) was used.

[0110] [Example 4] A glass cloth with a thickness of 29 μm was prepared in the same manner as in Example 1, except that the low-dielectric glass yarn listed in the table below (TEX 4.9, 100 filaments, elastic modulus 61 GPa, glass composition: 51.2 mass% in terms of SiO2, 14.3 mass% in terms of Al2O3, 8.1 mass% in terms of CaO, 0.3 mass% in terms of MgO, 23.3 mass% in terms of B2O3, 0.1 mass% in terms of P2O3) was used.

[0111] [Comparative Example 1] A glass cloth with a thickness of 29 μm was prepared in the same manner as in Example 1, except that the low-dielectric glass yarn listed in the table below (TEX 4.9, 100 filaments, elastic modulus 61 GPa, glass composition: 51.2 mass% in terms of SiO2, 14.3 mass% in terms of Al2O3, 8.1 mass% in terms of CaO, 0.3 mass% in terms of MgO, 23.3 mass% in terms of B2O3, 0.1 mass% in terms of P2O3) was used.

[0112] [Comparative Example 2] A glass cloth with a thickness of 29 μm was prepared in the same manner as in Example 1, except that the low-dielectric glass yarn listed in the table below (TEX 4.9, 100 filaments, elastic modulus 61 GPa, glass composition: 51.2 mass% in terms of SiO2, 14.3 mass% in terms of Al2O3, 8.1 mass% in terms of CaO, 0.3 mass% in terms of MgO, 23.3 mass% in terms of B2O3, 0.1 mass% in terms of P2O3) was used.

[0113] [Comparative Example 3] A glass cloth with a thickness of 29 μm was prepared in the same manner as in Example 1, except that the low-dielectric glass yarn listed in the table below (TEX 4.9, 100 filaments, elastic modulus 61 GPa, glass composition: 51.2 mass% in terms of SiO2, 14.3 mass% in terms of Al2O3, 8.1 mass% in terms of CaO, 0.3 mass% in terms of MgO, 23.3 mass% in terms of B2O3, 0.1 mass% in terms of P2O3) was used.

[0114] [Example 5] A glass cloth with a thickness of 29 μm was fabricated in the same manner as in Example 1, except that the loom rotation speed in the air jet room was set to 550 rpm.

[0115] [Example 6] A glass cloth with a thickness of 29 μm was fabricated in the same manner as in Example 3, except that the loom rotation speed in the air jet room was set to 550 rpm.

[0116] [Comparative Example 4] A glass cloth with a thickness of 29 μm was fabricated in the same manner as in Comparative Example 1, except that the loom rotation speed in the air jet room was set to 550 rpm.

[0117] [Example 7] A glass cloth with a thickness of 29 μm was fabricated in the same manner as in Example 1, except that the rotation speed of the loom in the air jet room was set to 600 rpm.

[0118] [Example 8] A glass cloth with a thickness of 29 μm was fabricated in the same manner as in Example 3, except that the rotation speed of the loom in the air jet room was set to 600 rpm.

[0119] [Comparative Example 5] A glass cloth with a thickness of 29 μm was fabricated in the same manner as in Comparative Example 1, except that the loom rotation speed in the air jet room was set to 600 rpm.

[0120] [Example 9] The water pressure of the high-pressure water spray used in the fiber opening process was 12.0 ± 0.1 kg / cm². 2 A glass cloth with a thickness of 29 μm was prepared in the same manner as in Example 1, except that the fiber opening strength was increased by raising the temperature.

[0121] [Example 10] The water pressure of the high-pressure water spray used in the fiber opening process was 12.0 ± 0.1 kg / cm². 2 A glass cloth with a thickness of 29 μm was prepared in the same manner as in Example 3, except that the fiber opening strength was increased by raising the temperature.

[0122] [Comparative Example 6] The water pressure of the high-pressure water spray used in the fiber opening process was 12.0 ± 0.1 kg / cm². 2 A glass cloth with a thickness of 29 μm was prepared in the same manner as in Comparative Example 1, except that the fiber opening strength was increased by raising the temperature.

[0123] [Comparative Example 7] The water pressure of the high-pressure water spray used in the fiber opening process was 12.0 ± 0.1 kg / cm². 2 A glass cloth with a thickness of 29 μm was prepared in the same manner as in Comparative Example 2, except that the fiber opening strength was increased by raising the temperature.

[0124] [Comparative Example 8] The water pressure of the high-pressure water spray used in the fiber opening process was 12.0 ± 0.1 kg / cm². 2 A glass cloth with a thickness of 29 μm was prepared in the same manner as in Comparative Example 3, except that the fiber opening strength was increased by raising the temperature.

[0125] [Example 11] Using the low-dielectric glass yarns listed in the table below (TEX 2.9, 100 filaments, elastic modulus 61 GPa, glass composition: 51.2 mass% in SiO2 equivalent, 14.3 mass% in Al2O3 equivalent, 8.1 mass% in CaO equivalent, 0.3 mass% in MgO equivalent, 23.3 mass% in B2O3 equivalent, 0.1 mass% in P2O3 equivalent) for both warp and weft threads, a glass cloth fabric with a warp weave density of 74 threads / 25 mm was obtained under the conditions of a loom rotation speed of 450 rpm (weft thread insertion speed of 450 threads / min) in an air jet room.

[0126] Next, the glass cloth is de-sticked by heating, and the water pressure is set to 4.0 ± 0.1 kg / cm². 2 High-pressure water fiber splitting was performed using a spray adjusted to the specified pressure, followed by surface treatment with a silane coupling agent to produce a glass cloth with a thickness of 21 μm.

[0127] [Example 12] A glass cloth with a thickness of 21 μm was prepared in the same manner as in Example 11, except that the low-dielectric glass yarn listed in the table below (TEX2.9, 100 filaments, elastic modulus 61 GPa, glass composition: 51.2 mass% in terms of SiO2, 14.3 mass% in terms of Al2O3, 8.1 mass% in terms of CaO, 0.3 mass% in terms of MgO, 23.3 mass% in terms of B2O3, 0.1 mass% in terms of P2O3) was used.

[0128] [Comparative Example 9] A glass cloth with a thickness of 21 μm was prepared in the same manner as in Example 11, except that the low-dielectric glass yarn listed in the table below (TEX2.9, 100 filaments, elastic modulus 61 GPa, glass composition: 51.2 mass% in terms of SiO2, 14.3 mass% in terms of Al2O3, 8.1 mass% in terms of CaO, 0.3 mass% in terms of MgO, 23.3 mass% in terms of B2O3, 0.1 mass% in terms of P2O3) was used.

[0129] [Example 13] The water pressure of the high-pressure water spray used in the fiber opening process is set to 10.0 ± 0.1 kg / cm². 2 A glass cloth with a thickness of 21 μm was prepared in the same manner as in Example 11, except that the fiber opening strength was increased by raising the temperature.

[0130] [Comparative Example 10] The water pressure of the high-pressure water spray used in the fiber opening process is set to 10.0 ± 0.1 kg / cm². 2 A glass cloth with a thickness of 21 μm was prepared in the same manner as in Comparative Example 9, except that the fiber opening strength was increased by raising the temperature.

[0131] [Example 14] Using the low-dielectric glass yarns listed in the table below (TEX 9.8, 200 filaments, elastic modulus 61 GPa, glass composition: 51.2 mass% in SiO2 equivalent, 14.3 mass% in Al2O3 equivalent, 8.1 mass% in CaO equivalent, 0.3 mass% in MgO equivalent, 23.3 mass% in B2O3 equivalent, 0.1 mass% in P2O3 equivalent) for both warp and weft threads, a glass cloth fabric with a warp weave density of 52.5 threads / 25 mm was obtained under the conditions of a loom rotation speed of 450 rpm (weft thread insertion speed of 450 threads / min) in an air jet room.

[0132] Next, the glass cloth is de-sticked by heating, and the water pressure is set to 6.0 ± 0.1 kg / cm². 2 High-pressure water splitting was performed using a spray adjusted to the specified pressure, followed by surface treatment with a silane coupling agent to produce a glass cloth with a thickness of 46 μm.

[0133] [Example 15] A glass cloth with a thickness of 46 μm was prepared in the same manner as in Example 14, except that the low-dielectric glass yarn listed in the table below (TEX9.8, 200 filaments, elastic modulus 61 GPa, glass composition: 51.2 mass% in terms of SiO2, 14.3 mass% in terms of Al2O3, 8.1 mass% in terms of CaO, 0.3 mass% in terms of MgO, 23.3 mass% in terms of B2O3, 0.1 mass% in terms of P2O3) was used.

[0134] [Comparative Example 11] A glass cloth with a thickness of 46 μm was prepared in the same manner as in Example 14, except that the low-dielectric glass yarn listed in the table below (TEX9.8, 200 filaments, elastic modulus 61 GPa, glass composition: 51.2 mass% in terms of SiO2, 14.3 mass% in terms of Al2O3, 8.1 mass% in terms of CaO, 0.3 mass% in terms of MgO, 23.3 mass% in terms of B2O3, 0.1 mass% in terms of P2O3) was used.

[0135] [Example 16] The water pressure of the high-pressure water spray used in the fiber opening process was 12.0 ± 0.1 kg / cm². 2 A glass cloth with a thickness of 46 μm was prepared in the same manner as in Example 14, except that the fiber opening strength was increased by raising the temperature.

[0136] [Comparative Example 12] The water pressure of the high-pressure water spray used in the fiber opening process was 12.0 ± 0.1 kg / cm². 2 A glass cloth with a thickness of 46 μm was prepared in the same manner as in Comparative Example 11, except that the fiber opening strength was increased by raising the temperature.

[0137] [Example 17] Using the low-dielectric glass yarns listed in the table below (TEX 4.8, 100 filaments, elastic modulus 56 GPa, glass composition: 49.8 mass% in SiO2 equivalent, 16.8 mass% in Al2O3 equivalent, 3.1 mass% in CaO equivalent, 0.1 mass% in MgO equivalent, 23.9 mass% in B2O3 equivalent, 4.0 mass% in P2O3 equivalent) for both warp and weft threads, a glass cloth fabric with a warp weave density of 65 / 25 mm and a weft weave density of 67 / 25 mm was obtained under the conditions of a loom rotation speed of 450 rpm (weft thread insertion speed of 450 threads / min) in an air jet room.

[0138] Next, the glass cloth is de-sticked by heating, and the water pressure is set to 5.0 ± 0.1 kg / cm². 2 High-pressure water splitting was performed using a spray adjusted to the specified pressure, followed by surface treatment with a silane coupling agent to produce a glass cloth with a thickness of 31 μm.

[0139] [Example 18] A glass cloth with a thickness of 31 μm was prepared in the same manner as in Example 17, except that the low-dielectric glass yarn listed in the table below (TEX 4.8, 100 filaments, elastic modulus 56 GPa, glass composition: 49.8 mass% in terms of SiO2, 16.8 mass% in terms of Al2O3, 3.1 mass% in terms of CaO, 0.1 mass% in terms of MgO, 23.9 mass% in terms of B2O3, 4.0 mass% in terms of P2O3) was used.

[0140] [Comparative Example 13] A glass cloth with a thickness of 31 μm was prepared in the same manner as in Example 15, except that the low-dielectric glass yarn listed in the table below (TEX 4.8, 100 filaments, elastic modulus 56 GPa, glass composition: 49.8 mass% in terms of SiO2, 16.8 mass% in terms of Al2O3, 3.1 mass% in terms of CaO, 0.1 mass% in terms of MgO, 23.9 mass% in terms of B2O3, 4.0 mass% in terms of P2O3) was used.

[0141] [Example 19] The water pressure of the high-pressure water spray used in the fiber opening process was 12.0 ± 0.1 kg / cm². 2 A glass cloth with a thickness of 31 μm was prepared in the same manner as in Example 17, except that the fiber opening strength was increased by raising the temperature.

[0142] [Comparative Example 14] The water pressure of the high-pressure water spray used in the fiber opening process was 12.0 ± 0.1 kg / cm². 2 A glass cloth with a thickness of 31 μm was prepared in the same manner as in Comparative Example 13, except that the fiber opening strength was increased by raising the density.

[0143] [Reference Example 1a] Using low-dielectric glass yarn with 5 to 10 slipped filaments (TEX 14.6, 200 filaments, elastic modulus 61 GPa, glass composition: 51.2 mass% in SiO2 equivalent, 14.3 mass% in Al2O3 equivalent, 8.1 mass% in CaO equivalent, 0.3 mass% in MgO equivalent, 23.3 mass% in B2O3 equivalent, 0.1 mass% in P2O3) for both warp and weft, a glass cloth fabric with a warp weave density of 59 threads / 25 mm and a weft weave density of 61 threads / 25 mm was obtained under the conditions of a loom rotation speed of 450 rpm (weft thread insertion speed of 450 threads / min) in an air jet room.

[0144] Next, the glass cloth is de-sticked by heating, and the water pressure is set to 7.0 ± 0.1 kg / cm². 2 High-pressure water splitting was performed using a spray adjusted to the specified pressure, followed by surface treatment with a silane coupling agent to produce a glass cloth with a thickness of 73 μm.

[0145] [Reference example 1b] The water pressure of the high-pressure water spray used in the fiber opening process was 12.0 ± 0.1 kg / cm². 2 A glass cloth with a thickness of 73 μm was prepared in the same manner as in Reference Example 1a, except that the fiber opening strength was increased by raising the density.

[0146] [Reference example 2a] Low dielectric glass yarn with 5 to 10 slipped filaments (TEX 19.4, 200 filaments, elastic modulus 61 GPa, glass composition: 51.2 mass% in SiO2 equivalent, 14.3 mass% in Al2O3 equivalent, 8.1 mass% in CaO equivalent, 0.3 mass% in MgO equivalent, 23.3 mass% in B2O3 equivalent, 0.1 mass% in P2O3 equivalent) was used for both the warp and weft threads. Under the conditions of an air-jet loom with a rotation speed of 450 rpm (weft thread insertion speed of 450 threads / min), a glass cloth fabric with a warp weave density of 60 threads / 25 mm and a weft weave density of 57 threads / 25 mm was obtained.

[0147] Next, the glass cloth is de-sticked by heating, and the water pressure is set to 7.0 ± 0.1 kg / cm². 2High-pressure water splitting was performed using a spray adjusted to the specified pressure, followed by surface treatment with a silane coupling agent to produce a glass cloth with a thickness of 89 μm.

[0148] [Reference example 2b] The water pressure of the high-pressure water spray used in the fiber opening process was 12.0 ± 0.1 kg / cm². 2 A glass cloth with a thickness of 89 μm was prepared in the same manner as in Reference Example 2a, except that the fiber opening strength was increased by raising the density.

[0149] [Reference example 3a] Using E glass yarn (TEX5.5, 100 filaments, elastic modulus 74GPa, glass composition: 53.1 mass% SiO2 equivalent, 15.3 mass% Al2O3 equivalent, 21.0 mass% CaO equivalent, 1.9 mass% MgO equivalent, 8.0 mass% B2O3 equivalent, <0.1 mass% P2O3 equivalent) with 5 to 10 slipped filaments for both warp and weft, and under the conditions of a loom rotation speed of 450 rpm in an air jet room (weft thread insertion speed of 450 threads / min), a glass cloth fabric with a warp weave density of 65 threads / 25 mm and a weft weave density of 67 threads / 25 mm was obtained.

[0150] Next, the glass cloth is de-sticked by heating, and the water pressure is set to 5.0 ± 0.1 kg / cm². 2 High-pressure water fiber splitting was performed using a spray adjusted to the specified pressure, followed by surface treatment with a silane coupling agent to produce a glass cloth with a thickness of 29 μm.

[0151] [Reference example 3b] The water pressure of the high-pressure water spray used in the fiber opening process was 12.0 ± 0.1 kg / cm². 2 A glass cloth with a thickness of 89 μm was prepared in the same manner as in Reference Example 3a, except that the fiber opening strength was increased by raising the density.

[0152] The evaluation results for glass yarn and glass cloth in the above examples, comparative examples, and reference examples are shown in the table below. In the table, "Water pressure during high-pressure water fiber opening (kg / cm²)" is used. 2 In the item ")", it states "±0.1 (kg / cm 2The notation ")" is omitted in the example.

[0153] [Table 2-1]

[0154] [Table 2-2]

[0155] [Table 2-3]

[0156] [Table 2-4]

[0157] [Table 2-5]

[0158] [Table 2-6]

[0159] [Table 2-7]

[0160] [Table 2-8]

[0161] [Table 2-9]

[0162] Examples 1-4, 11, 12, 14, 15, 17, and 18 yielded glass cloth with excellent fluff quality. The glass yarn used in these examples had three or fewer slipped filaments measured from the starting point T0, suggesting that the number of slipped filaments was low throughout the entire glass yarn wound on the bobbin. It was confirmed that using such glass yarn yields glass cloth with excellent fluff quality.

[0163] In Examples 5-8, even when the loom rotation speed was increased from 450 rpm to 550 rpm or 600 rpm to improve productivity in the weaving process, the fluff quality did not deteriorate significantly, and glass cloth with relatively good fluff quality was obtained.

[0164] Examples 9, 10, 13, 16, and 19 showed that by increasing the water pressure of the high-pressure water spray, low-dielectric glass cloths were obtained with improved impregnation properties while maintaining relatively good fluff quality.

[0165] On the other hand, the glass cloths obtained in Comparative Examples 1-3, 9, 11, and 13 were inferior in terms of fluff quality.

[0166] Furthermore, in Comparative Examples 4-8, 10, 12, and 14, increasing the loom rotation speed from 450 rpm to 550 rpm or 600 rpm during the weaving process, or increasing the water pressure of the high-pressure water spray during the fiber opening process, resulted in glass cloth with significantly inferior fluff quality.

[0167] In Reference Example 1(a,b) and Reference Example 2(a,b), the thicknesses were 73 μm and 89 μm, respectively, which were not as thin as the glass cloths used in Examples 1-16.

[0168] Reference Example 3(a,b) using E glass yarn yielded a glass cloth with relatively good fluff quality. With low-dielectric glass yarns of equivalent TEX, a higher number of slipped filaments tends to lead to a decrease in fluff quality as the spray pressure of the high-pressure water spray increases (Comparative Examples 1-3, 6-8), whereas, based on the results of Reference Example 3, no such tendency was observed with E glass yarn.

[0169] In Examples 1-4 and Comparative Examples 1-3, the number of slipped filaments was found to reflect the fluff quality of the glass cloth more accurately than the number of fluff generated when a load was applied to the glass yarn, compared to the number of fluff samples taken from the bobbin.

Claims

1. A glass cloth woven using glass threads containing multiple glass filaments as both warp and weft threads, The glass yarn includes a glass yarn in which the number of slipped filaments is 3 or less, which is more than twice the average yarn width when measured over 180m. When a 500m length of the aforementioned glass cloth is irradiated with white LED light along its surface and observed every 1m along the length, and when the presence of fuzz across the entire surface of the cloth is counted as one defect, the following formula is used: Deduction rate (%) = (Total number of defects / 500) × 100 Glass cloth with a deduction rate of 0-3.5%, as shown by [formula].

2. The glass cloth according to claim 1, wherein the overall fluffiness includes fluffing of 200 to 1000 μm due to the breakage of the filaments, as observed on the cloth surface by optical microscope.

3. The glass cloth according to claim 1, wherein the thickness of the glass cloth is 10 to 50 μm.

4. The following conditions: (i) TEX is 1 to 13, (ii) The breaking strength is 0.50 to 0.80 N / tex, and (iii) The number of slipped filaments is 3 or less, and is more than twice the average thread width when measured over 180m. The glass cloth according to claim 1, comprising the glass yarn that satisfies the requirements.

5. The glass cloth according to claim 1, comprising the glass yarn having a twist interval length of 1.8 to 10.0 cm.

6. The glass cloth according to claim 1, wherein the glass yarn has a value (twist interval length difference index) of 0.7 or less, which is the difference between the maximum and minimum twist interval lengths of the glass yarn divided by the average value of the twist interval lengths.

7. Targeting the glass yarn having a length of 10,000 m or more, The glass cloth according to any one of claims 1 to 6, wherein when a measurement range of 180 m in the longitudinal direction is selected at five different locations, the number of filaments that have slipped off is 3 or less in each of the five measurement ranges, which is 2 times or more the average yarn width.

8. The glass yarn having a length of 50,000 m or more, The glass cloth according to any one of claims 1 to 6, wherein when a measurement range of 180 m in the longitudinal direction is selected at seven different locations, the number of filaments that have slipped out is 3 or less in each of the seven measurement ranges, which is 2 times or more the average yarn width.

9. The glass yarn having a length of 100,000 m or more, The glass cloth according to any one of claims 1 to 6, wherein when a measurement range of 180 m in the longitudinal direction is selected at 10 different locations, the number of filaments that have slipped out is 3 or less in each of the 10 measurement ranges, which is 2 times or more the average yarn width.

10. A method for manufacturing glass cloth, comprising the step of weaving using glass yarn containing multiple glass filaments as warp and weft threads, (i) The TEX of the glass yarn is 1 to 13, (ii) The breaking strength of the glass fiber is 0.50 to 0.80 N / tex, and (iii) The number of slipped filaments is 3 or less, and is more than twice the average thread width when measured over 180m. A method for manufacturing glass cloth.

11. The method for manufacturing glass cloth according to claim 10, wherein the TEX of the glass yarn is 1 to 7.

12. The method for manufacturing glass cloth according to claim 10, wherein the number of monoglass filaments constituting the glass thread is 30 to 120.

13. The method for manufacturing glass cloth according to claim 10, wherein the twist interval length of the glass yarn is 1.8 to 10.0 cm.

14. The method for manufacturing glass cloth according to claim 10, wherein the value obtained by dividing the difference between the maximum and minimum twist interval lengths of the glass yarn by the average value of the twist interval lengths (twist interval length difference index) is 0.7 or less.

15. The density of the aforementioned glass fiber is 2.2 g / cm³. ３ 2.5g / cm or more ３ A method for manufacturing glass cloth according to claim 10, wherein the result is less than [amount missing].

16. The method for manufacturing glass cloth according to claim 10, wherein the elastic modulus of the glass yarn is 50 to 70 GPa.

17. The method for manufacturing glass cloth according to claim 10, wherein the elastic modulus of the glass yarn is 50 to 63 GPa.

18. Targeting the glass yarn having a length of 10,000 m or more, A method for manufacturing glass cloth according to any one of claims 10 to 17, wherein when a measurement range of 180 m in the longitudinal direction is selected at five different locations, the number of filaments that have slipped out to twice or more the average yarn width is 3 or less in each of the five measurement ranges.

19. The glass yarn having a length of 50,000 m or more, A method for manufacturing glass cloth according to any one of claims 10 to 17, wherein when a measurement range of 180 m in the longitudinal direction is selected at seven different locations, the number of filaments that have slipped out to twice or more the average yarn width is three or less in each of the seven measurement ranges.

20. The glass yarn having a length of 100,000 m or more, A method for manufacturing glass cloth according to any one of claims 10 to 17, wherein when a measurement range of 180 m in the longitudinal direction is selected at 10 different locations, the number of filaments that have slipped out to twice or more the average yarn width is 3 or less in each of the 10 measurement ranges.

21. (i) TEX is 1 to 13, (ii) The breaking strength is 0.50 to 0.80 N / tex, and (iii) The number of slipped filaments is 3 or less, and is more than twice the average thread width when measured over 180m. Glass thread.

22. The glass yarn according to claim 21, wherein the TEX is 1 to 7.

23. The glass yarn according to claim 21, wherein the number of monoglass filaments constituting the glass yarn is 30 to 120.

24. The glass yarn according to claim 21, wherein the twist interval length is 1.8 to 10.0 cm.

25. The glass yarn according to claim 21, wherein the value obtained by dividing the difference between the maximum and minimum twist interval lengths by the average value of the twist interval lengths (twist interval length difference index) is 0.7 or less.

26. The density is 2.2 g / cm³. ３ 2.5g / cm or more ３ The glass yarn according to claim 21, which is less than [amount missing].

27. The glass yarn according to claim 21, wherein the elastic modulus is 50 to 70 GPa.

28. The glass yarn according to claim 21, wherein the elastic modulus is 50 to 63 GPa.

29. Targeting the glass yarn having a length of 10,000 m or more, The glass yarn according to any one of claims 21 to 28, wherein when a measurement range of 180 m in the longitudinal direction is selected at five different locations, the number of filaments that have slipped out to twice or more the average yarn width is 3 or less in each of the five measurement ranges.

30. The glass yarn having a length of 50,000 m or more, The glass yarn according to any one of claims 21 to 28, wherein when a measurement range of 180 m in the length direction is selected at seven different locations, the number of filaments that have slipped out to twice or more the average yarn width is three or less in each of the seven measurement ranges.

31. The glass yarn having a length of 100,000 m or more, The glass yarn according to any one of claims 21 to 28, wherein when a measurement range of 180 m in the length direction is selected at 10 different locations, the number of filaments that have slipped out to twice or more the average yarn width is 3 or less in each of the 10 measurement ranges.

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