Glass cloth manufacturing method and glass yarn

Abstract

To provide a method for manufacturing a low-dielectric glass cloth with uniform quality and a glass yarn suitable for manufacturing the low-dielectric glass cloth.SOLUTION: In the method for manufacturing a glass cloth obtained by weaving glass yarns, composed of a plurality of glass filaments, as warp yarns and weft yarns, density of the glass yarns as the weft yarns is 2.2 g / cm3 or more and 2.5 g / cm3 or less and yarn width variation of the glass yarn as the weft yarns (yarn width dispersion coefficient) is 0.003 or more and 0.013 or less and / or a yarn width distribution variation coefficient A which indicates yarn width distribution variation of the glass yarns as the weft yarns is 0.0002 or more and 0.0015 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing glass cloth and a glass yarn. [Background technology]

[0002] With the recent development of the information and communications society, data communication and / or signal processing have become large-volume and high-speed, and the dielectric constant of printed wiring boards used in electronic devices has been significantly reduced. For this reason, many low-dielectric glass cloths have been proposed as glass cloths for use in printed wiring boards.

[0003] For example, the low dielectric glass cloth disclosed in Patent Document 1 achieves a low dielectric constant by incorporating a large amount of B2O3 into the glass composition, as compared to the E-glass cloth that has been commonly used in the past, while simultaneously adjusting the amounts of other components such as SiO2. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-292567 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors have conducted studies and found that low-dielectric glass cloths made from such low-dielectric glass yarns vary greatly in performance and quality compared to conventional E-glass cloths. Such variations in performance and quality of glass cloths affect the quality of prepregs, laminates for printed wiring boards, and other products obtained using the same.

[0006] The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for producing low dielectric glass cloth having uniform quality, and glass yarn suitable for producing low dielectric glass cloth. [Means for solving the problem]

[0007] As a result of intensive research to solve the above problems, the inventors discovered that the above problems can be solved by setting the width of the glass yarn, the range of variation in the width, and the uniformity of the range of variation in the width to specific ranges, and thus completed the present invention.

[0008] That is, the present invention is as follows. [1] A glass fabric made by weaving glass yarns consisting of a plurality of glass filaments as warp and weft yarns. A method for producing lath cloth, comprising: The density of the glass yarn that becomes the weft is 2.2 g / cm 3 More than 2.5g / cm 3 Less than can be, The yarn width dispersion coefficient indicating the yarn width variation of the glass yarn that becomes the weft yarn is 0.003 or more is less than or equal to .013, and / or The yarn width distribution variation coefficient A, which indicates the yarn width distribution variation of the glass yarn that becomes the weft yarn, is 0 Between .0002 and 0.0015, Glass cloth manufacturing method. Yarn width dispersion coefficient = Standard deviation of yarn width (yarn width standard deviation A) of the glass filament Divide by the average diameter Yarn width distribution variation coefficient A = Calculate the standard deviation of yarn width (yarn width standard deviation B) for every 0.5 m length The standard deviation of the yarn width standard deviation B (standard deviation of yarn width distribution) is calculated by dividing the standard deviation of the glass fiber that constitutes the weft yarn. Value obtained by dividing by lament diameter [2] The density of the glass yarn is 2.2 g / cm 3 Excess, 2.5g / cm 3 is less than The yarn width dispersion coefficient is more than 0.003 and less than 0.010, And / or, the yarn width distribution variation coefficient A is more than 0.0003 and less than 0.0012; A method for producing the glass cloth according to [1]. [3] The yarn width distribution coefficient is 0.005 or more and 0.013 or less, The yarn width distribution variation coefficient A is 0.0006 or more and 0.0015 or less, and / or 、 A yarn width distribution showing the distribution variation of the yarn width of the glass yarn that becomes the weft yarn. The coefficient of variation B is 0.013 or more and 0.027 or less. A method for producing the glass cloth according to [1]. Yarn width distribution variation coefficient B = Calculate the standard deviation of yarn width (yarn width standard deviation B) for every 0.5 m length The standard deviation of the yarn width standard deviation B (standard deviation of the yarn width distribution) is calculated by dividing the average value of the yarn width standard deviation B by the The yarn width distribution CV value, which is obtained by dividing the CV value by the diameter of the glass filaments that make up the weft yarn, is calculated. Values ​​that can be set [4] The average number of twists per 25 mm of the weft is 0.50 or more and 1.20 or less, The standard deviation indicating the variation in the number of twists is 0.10 or more and 0.20 or less. The method for producing glass cloth according to any one of [1] to [3]. [5] The weft yarn is made of 80 glass filaments having an average diameter of more than 4.5 μm and not more than 5.5 μm. The glass yarn is a bundle of 120 or more strands, and the average width of the glass yarn is 90 μm or more and 13 0 μm or less, The method for producing glass cloth according to any one of [1] to [4]. [6] The weft yarn is made of 180 glass filaments having an average diameter of more than 4.5 μm and not more than 5.5 μm. The glass yarn is a bundle of 220 or more strands, and the average width of the glass yarn is 120 μm. is greater than or equal to 175 μm, The method for producing glass cloth according to any one of [1] to [4]. [7] The weft yarn is made of 180 glass filaments having an average diameter of more than 5.5 μm and not more than 6.5 μm. The glass fibers are bundled together with 220 or more strands, and the average width of the glass fibers is 155 μm or more. 195 μm or less, The method for producing glass cloth according to any one of [1] to [4]. [8] The weft yarn is made of 180 glass filaments having an average diameter of more than 6.5 μm and not more than 7.5 μm. The glass fibers are bundled together with 220 or more strands, and the average width of the glass fibers is 180 μm or more. 220 μm or less, The method for producing glass cloth according to any one of [1] to [4]. [9] The elastic modulus of the glass yarn is 50 to 70 GPa. The method for producing glass cloth according to any one of [1] to [8].

[10] The elastic modulus of the glass yarn is 50 to 63 GPa. [9] A method for producing glass cloth according to [9].

[11] The glass cloth has a dielectric constant of 5.0 or less at a frequency of 1 GHz.

[10] A method for producing a glass cloth according to any one of [1] to

[10] .

[12] The glass yarn, The Si content is 40 to 60 mass% in terms of SiO2, The B content is 15 to 30 mass% in terms of B2O3.

[11] The method for producing glass cloth according to any one of [1] to

[11] .

[13] Density: 2.2g / cm 3 More than 2.5g / cm 3 is less than The yarn width dispersion coefficient, which indicates the variation in yarn width, is 0.003 or more and 0.013 or less, and / or teeth, The yarn width distribution variation coefficient A, which indicates the distribution variation of the yarn width, is 0.0002 or more and 0.0015 or less. That is, Glass thread. Yarn width dispersion coefficient = Standard deviation of yarn width (yarn width standard deviation A) of the glass filament Divide by the average diameter Yarn width distribution variation coefficient A = Calculate the standard deviation of yarn width (yarn width standard deviation B) for every 0.5 m length The standard deviation of the yarn width standard deviation B (standard deviation of yarn width distribution) is calculated by dividing the standard deviation of the glass fiber that constitutes the weft yarn. Value obtained by dividing by lament diameter

[14] The density of the glass yarn is 2.2 g / cm 3 Excess, 2.5g / cm 3 is less than The yarn width dispersion coefficient is more than 0.003 and less than 0.010, And / or, the yarn width distribution variation coefficient A is more than 0.0003 and less than 0.0012; The glass fiber according to

[13] .

[15] The yarn width distribution coefficient is 0.005 or more and 0.013 or less, The yarn width distribution variation coefficient A is 0.0006 or more and 0.0015 or less, and / or 、 A yarn width distribution showing the distribution variation of the yarn width of the glass yarn that becomes the weft yarn. The coefficient of variation B is 0.013 or more and 0.027 or less. The glass fiber according to

[13] . Yarn width distribution variation coefficient B = Calculate the standard deviation of yarn width (yarn width standard deviation B) for every 0.5 m length The standard deviation of the yarn width standard deviation B (standard deviation of the yarn width distribution) is calculated by dividing the average value of the yarn width standard deviation B by the The yarn width distribution CV value, which is obtained by dividing the CV value by the diameter of the glass filaments that make up the weft yarn, is calculated. Values ​​that can be set

[16] The average number of twists per 25 mm is 0.50 or more and 1.20 or less, The standard deviation indicating the variation in the number of twists is 0.10 or more and 0.20 or less.

[13] The glass fiber according to any one of

[15] to

[16] .

[17] 80 to 120 glass filaments with an average diameter of more than 4.5 μm and less than 5.5 μm The following are bundled glass fibers, and the average width of the fibers is 90 μm or more and 130 μm or less. The glass fiber according to any one of

[13] to

[16] .

[18] 180 or more 220 glass filaments with an average diameter of more than 4.5 μm and less than 5.5 μm The glass fibers are bundled together in a bundle of 100 or less strands, and the average width of the fibers is 120 μm or more and 175 μm or less. , The glass fiber according to any one of

[13] to

[16] .

[19] 180 or more 220 glass filaments with an average diameter of more than 5.5 μm and less than 6.5 μm The glass yarn is bundled together in a bundle of 155 μm or less, and the average yarn width is 155 μm or more and 195 μm or less. The glass fiber according to any one of

[13] to

[16] .

[20] 180 or more 220 glass filaments with an average diameter of more than 6.5 μm and less than 7.5 μm The glass yarn is bundled together in a bundle of 180 μm or less, and the average yarn width is 180 μm or more and 220 μm or less. The glass fiber according to any one of

[13] to

[16] . 〔twenty one〕 The elastic modulus is 50 to 70 GPa. The glass fiber according to any one of

[13] to

[20] . 〔twenty two〕 The elastic modulus is 50 to 63 GPa. The glass fiber according to any one of

[13] to

[20] . 〔twenty three〕 A dielectric constant of 5.0 or less at a frequency of 1 GHz. The glass fiber according to any one of

[13] to

[22] . 〔twenty four〕 The Si content is 40 to 60 mass% in terms of SiO2, The B content is 15 to 30 mass% in terms of B2O3. The glass fiber according to any one of

[13] to

[23] . [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a method for producing a low dielectric glass cloth having uniform quality, and a glass yarn suitable for producing a low dielectric glass cloth. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a perspective view showing one aspect of a weaving step in the manufacturing method of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Below, we will explain in detail the embodiment of the present invention (hereinafter referred to as the ``present embodiment''), but the present invention is not limited to this and various modifications are possible within the scope of the gist of the present invention.

[0012] [Method for manufacturing glass cloth] The method for producing a glass cloth according to the present embodiment is a method for producing a glass cloth by weaving glass yarns consisting of a plurality of glass filaments as warp yarns and weft yarns, and the density of the glass yarns that become the weft yarns is 2.2 g / cm 3 More than 2.5g / cm 3 and a yarn width distribution coefficient indicating the yarn width variation of the glass yarn that becomes the weft is 0.003 or more and 0.013 or less, and / or a yarn width distribution variation coefficient A indicating the yarn width distribution variation of the glass yarn that becomes the weft is 0.0002 or more and 0.0015 or less.

[0013] It has been found that glass cloth manufactured using low-dielectric glass yarns varies in quality compared to conventional E-glass cloth, and that in rare cases, glass cloth of inferior quality is obtained. A detailed examination of glass cloths of relatively poor quality among these has revealed that they have in common the presence of unevenly distributed wide and narrow glass yarns, and that glass yarns with large variations in yarn width are used. Furthermore, glass cloths made from glass yarns with such large variations in yarn width distribution have many weaving defects, such as areas where the filaments that make up the glass yarns have been partially broken, creating a fuzz-like appearance, and areas where the weft yarns are loose.

[0014] The reason for this is not limited, but it is thought that glass yarns (weft yarns) that have an uneven distribution of wide and thin yarn widths have difficulty in obtaining a stable flight trajectory when woven, making it difficult for them to pass straight between the warp yarns, which makes them more likely to produce fuzz and weaving defects.

[0015] Furthermore, the E-glass glass yarns that have been used until now are heavier than low-dielectric glass yarns, and variations in yarn width have had little impact on weaving. However, with lighter low-dielectric glass yarns, the weft yarn is more susceptible to the effects of the yarn width shape when woven, which is thought to promote the occurrence of fuzz and weaving defects.

[0016] Furthermore, low-dielectric glass yarns, which have a small elastic modulus and are not strong against mechanical loads, are likely to cause filament breakage and promote the generation of fluff. These effects are thought to be reflected in the quality of the woven glass cloth.

[0017] In contrast, in this embodiment, the density of the glass yarn is 2.2 g / cm 3 More than 2.5g / cm 3By using a weft yarn having a weft width variation range (width distribution coefficient) of 0.003 to 0.013 or a weft width distribution range (width distribution variation coefficient A) of 0.0002 to 0.0015, the influence of the shape of the yarn width during weaving can be reduced even when a relatively light glass yarn with low dielectric constant is used. This makes it possible to suppress the occurrence of fluff and weaving defects and obtain glass cloth of uniform quality.

[0018] (Glass thread density) The density of the glass weft thread is 2.2g / cm 3 More than 2.5g / cm 3 less than 2.2 g / cm 3 Excess 2.5g / cm 3 more preferably less than 2.22 g / cm 3 More than 2.45g / cm 3 or less, and more preferably 2.25 g / cm 3 More than 2.4g / cm 3 The density of the glass yarn in the weft is 2.5 g / cm 3 If the density of the glass yarn in the weft is less than 2.2 g / cm, the flying trajectory is easily affected by the shape of the glass yarn when the weft is woven onto the discharged air, and quality defects such as fuzz and weaving defects are likely to occur. However, by setting the yarn width dispersion coefficient and yarn width distribution variation coefficient A of the weft within the specific ranges of the present invention, the flying trajectory can be stabilized, and a high-quality glass cloth can be stably obtained. 3 By satisfying the above, when the yarn width variation range and yarn width distribution variation range of the weft yarn are within the ranges of the present invention, the flying trajectory of the weft yarn can be stabilized. The glass density of the warp yarn may be the same as or different from the above ranges, but it is preferable that it is in the same range from the viewpoint of uniforming the properties of the glass cloth, such as the air permeability, resin impregnation, resin adhesiveness, and electrical properties, and from the viewpoint of obtaining a low dielectric glass cloth. The density of the glass yarn is 1 cm 3 The density of the bulk glass can be calculated as:

[0019] (Weft yarn width dispersion coefficient) The weft bundle has a width dispersion coefficient of 0.003 or more, preferably greater than 0.003, more preferably 0.004 or more, even more preferably 0.005 or more, still more preferably 0.006 or more, and particularly preferably 0.007 or more. The weft bundle also has a width dispersion coefficient of 0.013 or less, preferably less than 0.010, and more preferably 0.009 or less. Having a width dispersion coefficient within the above range means that when the weft is driven into an air jet loom, excessive air pressure is not required, and the weft can be inserted along a stable flight trajectory from the driving side to the opposite side, thereby enabling the consistent production of high-quality glass cloth with little fuzz or weaving defects.

[0020] The yarn width dispersion coefficient of a yarn bundle is a value obtained by dividing the standard deviation of the yarn width measurements of the yarn bundle by the average diameter of the glass filaments constituting the yarn bundle. The yarn width dispersion coefficient of the warp yarn bundle may be the same as or different from the above range, but is preferably in the same range from the viewpoint of further suppressing the occurrence of fluff and weaving defects. Yarn width dispersion coefficient = Value obtained by dividing the standard deviation of the yarn width (yarn width standard deviation A) by the average diameter of the glass filaments

[0021] (Weft width distribution variation coefficient A) The weft width distribution variation coefficient A is 0.0002 or more, preferably more than 0.0003, and more preferably 0.0004 or more. The weft width distribution variation coefficient A is 0.0015 or less, preferably less than 0.0012, and more preferably 0.0010 or less. When the weft width distribution variation coefficient A is within the above range, the weft yarn is likely to fly straight and stably without disruption of its flight trajectory, and a high-quality glass cloth with little fuzz or weaving defects can be stably obtained. This is presumably because the weft yarn can be uniformly exposed to compressed air in the length direction. Furthermore, when the yarn width distribution variation coefficient A is within the above range, the unwinding resistance when unwinding the yarn bundle from the bobbin is kept within a small range, and a high-quality glass cloth with little fuzz or weaving defects can be stably obtained. This is presumably because excessive overlap of the yarns on the bobbin on which they are wound can be avoided. If the yarn bundle frays during unwinding and one or several filaments separate, this will cause the filaments to break in the weaving process or in subsequent processes, resulting in fuzz or weaving defects.

[0022] When it is desired to stabilize the flight characteristics of the weft yarn and to place more importance on weaving productivity, the weft yarn width distribution variation coefficient A is 0.0002 or more and 0.0015 or less, and preferably 0.0006 or more and 0.0015 or less.

[0023] The yarn width distribution variation coefficient A of the yarn bundle is a value obtained by using the standard deviation (standard deviation A) of yarn width measurements in a specific short length range (e.g., 0.5 m) to determine the yarn width distribution state in a long length range (e.g., 50 m) as the standard deviation (standard deviation B = standard deviation of standard deviation A), and dividing this value by the average diameter of the filaments constituting the yarn bundle. The yarn width distribution variation coefficient A of the warp yarn bundle may be the same as or different from the above range, but is preferably in the same range from the viewpoint of further suppressing the occurrence of fuzz and weaving defects. Coefficient of variation of yarn width distribution A = Value obtained by dividing the standard deviation of yarn width standard deviation B (standard deviation of yarn width distribution) by the diameter of the glass filaments that make up the weft yarn when calculating the standard deviation of yarn width (standard deviation of yarn width B) for every 0.5 m length.

[0024] It is preferable that both the yarn width dispersion coefficient and the yarn width distribution variation coefficient A of the yarn bundle are within the above ranges.

[0025] The yarn width dispersion coefficient, yarn width distribution variation coefficient A, and average value of the yarn bundle can be calculated from the yarn width data obtained by measuring the yarn width of a glass yarn of 10 m or more at equal intervals shorter than 1 mm.

[0026] The method for measuring the filament width is not particularly limited, but for example, the glass filament width can be measured continuously while being continuously transported by irradiating it with LED light from the side and obtaining the width of the glass filament from the projected width of the portion where the LED light is blocked by the glass filament.The filament width can also be measured while observing it with a microscope.

[0027] (Weft width distribution variation coefficient B) The yarn width distribution variation coefficient B, which indicates the yarn width distribution variation of the glass yarn serving as the weft yarn, is preferably 0.013 or more, more preferably 0.014 or more, and even more preferably 0.015 or more. The yarn width distribution variation coefficient B is preferably 0.027 or less, more preferably 0.024 or less, and even more preferably 0.021 or less. When the yarn width distribution variation coefficient B is within the above range, the flying stability of the weft yarn tends to be further improved.

[0028] Coefficient of variation of yarn width distribution B = The value obtained by dividing the standard deviation of yarn width standard deviation B (yarn width distribution standard deviation) by the average value of yarn width standard deviation B when calculating the standard deviation of yarn width (yarn width standard deviation B) for each 0.5 m length, and then dividing the yarn width distribution CV value by the diameter of the glass filaments that make up the weft yarn.

[0029] (average value of thread width) In the method for producing a glass cloth of the present invention, when a glass cloth having a thickness of 20 μm or more and 38 μm or less is produced, it is preferable that a glass yarn formed by bundling 80 to 120 glass filaments having an average diameter of more than 4.5 μm and 5.5 μm or less is used as a weft yarn, and that the average yarn width of the weft yarn is 90 μm or more and 130 μm or less. In this case, the average yarn width is more preferably 95 μm or more, even more preferably 100 μm or more, and particularly preferably 102 μm or more. Furthermore, the average yarn width is more preferably 125 μm or less, even more preferably 122 μm or less, and particularly preferably 120 μm or less.

[0030] When producing a glass cloth having a thickness of 39 μm or more and 63 μm or less, a glass yarn formed by bundling 180 to 220 glass filaments having an average diameter of more than 4.5 μm and not more than 5.5 μm is preferably used as the weft yarn, and the average yarn width of the weft yarn is preferably 120 μm or more and 175 μm or less. In this case, the average yarn width is more preferably 125 μm or more, and even more preferably 130 μm or more. The average yarn width is more preferably 170 μm or less, even more preferably 165 μm or less, and particularly preferably 150 μm or less.

[0031] In the case of producing a glass cloth having a thickness of 64 μm or more and 83 μm or less, a glass yarn formed by bundling 180 to 220 glass filaments having an average diameter of more than 5.5 μm and 6.5 μm or less is preferably used as the weft yarn, and the average yarn width of the weft yarn is preferably 155 μm or more and 195 μm or less. In this case, the average yarn width is more preferably 160 μm or more, and even more preferably 162 μm or more. The average yarn width is more preferably 191 μm or less, even more preferably 183 μm or less, and particularly preferably 170 μm or less.

[0032] When producing a glass cloth having a thickness of 84 μm or more and 100 μm or less, a glass yarn formed by bundling 180 to 220 glass filaments having an average diameter of more than 6.5 μm and not more than 7.5 μm is preferably used as the weft yarn, and the average yarn width of the weft yarn is preferably 180 to 220 μm. In this case, the average yarn width is more preferably 185 μm or more, and even more preferably 190 μm or more. The average yarn width is more preferably 215 μm or less, and even more preferably 210 μm or less.

[0033] When the average width of the weft yarn is equal to or less than the above upper limit, the effect of any variation in yarn width is reduced, and the occurrence of fuzz and weaving defects in the obtained glass cloth tends to be suppressed. Furthermore, when the average width is equal to or more than the above lower limit, the glass yarn is appropriately exposed to the injected air during weft driving, and the weft can be blown out with a relatively gentle injection pressure, so the occurrence of fuzz and weaving defects in the obtained glass cloth tends to be suppressed. Note that the average width of the warp yarn may be the same as or different from the above range, but from the viewpoint of further suppressing the occurrence of fuzz and weaving defects, it is preferably within the same range.

[0034] (variation in twist number) The standard deviation indicating the variation in the number of twists per 25 mm of the weft yarn is preferably 0.03 or more, more preferably 0.05 or more, and even more preferably 0.10 or more. The standard deviation indicating the variation in the number of twists per 25 mm of the weft yarn is preferably 0.20 or less, more preferably 0.18 or less, even more preferably 0.15 or less, and particularly preferably 0.13 or less. When the standard deviation of the number of twists is within the above range, the influence of the shape of the yarn width during weaving is reduced, and the occurrence of fluff and weaving defects in the resulting glass cloth tends to be suppressed. Furthermore, when the standard deviation of the number of twists is within the above range, the glass cloth tends to have excellent solder heat resistance.

[0035] The standard deviation indicating the variation in the number of twists per 25 mm of the warp yarn is preferably 0.03 or more, more preferably 0.05 or more, and even more preferably 0.10 or more. The standard deviation indicating the variation in the number of twists per 25 mm of the warp yarn is preferably 0.20 or less, more preferably 0.18 or less, even more preferably 0.15 or less, and particularly preferably 0.13 or less. A standard deviation of the number of twists within the above range is preferred from the viewpoint of further suppressing the occurrence of fuzz and weaving defects. Furthermore, having a standard deviation of the number of twists within the above range tends to result in excellent solder heat resistance. The standard deviations of the number of twists of the weft yarn and the warp yarn may be the same or different.

[0036] The reason why excellent soldering heat resistance is achieved by having a standard deviation indicating the variation in the number of twists per 25 mm of weft and / or warp yarns within the above range is not particularly limited, but is thought to be as follows: When the standard deviation indicating the variation in the number of twists is 0.10 or more, adjacent yarns are prevented from coming into excessive contact with each other, and an appropriate gap is formed between adjacent yarns, which improves the resin impregnation of the glass cloth and tends to improve the adhesion between the glass yarns and the resin. It is therefore believed that soldering heat resistance is further improved. Furthermore, when the standard deviation indicating the variation in the number of twists is 0.20 or less, the distribution of the glass yarns is more uniform in the resulting glass cloth and in the substrate obtained by impregnating the glass cloth with resin, which tends to prevent the occurrence of locally weak areas. It is therefore believed that soldering heat resistance is further improved.

[0037] (Average number of twists) The average number of twists per 25 mm of the weft yarn is preferably 0.50 to 1.20, more preferably 0.60 to 1.10, and even more preferably 0.65 to 1.05. When the average number of twists is within the above range, the influence of the shape of the yarn width during weaving is reduced, and the occurrence of fluff and weaving defects in the obtained glass cloth tends to be suppressed.

[0038] The average number of twists per 25 mm of the warp yarns is preferably 0.50 to 1.20, more preferably 0.60 to 1.10, and even more preferably 0.65 to 1.05. It is preferable that the average number of twists be within the above range in order to further suppress the occurrence of fluff and weaving defects. The average number of twists of the weft yarns and the warp yarns may be the same or different.

[0039] (Glass thread composition) Next, the structure of the glass yarn will be explained. The glass yarn is obtained by bundling a plurality of glass filaments and twisting them as necessary. In this case, the glass yarn is classified as a multifilament, and the glass filament is classified as a monofilament.

[0040] The average diameter of the glass filaments constituting the warp and weft is preferably 2.5 to 9 μm, more preferably 3.0 to 7.5 μm, and even more preferably 3.5 to 5.4 μm. When the average diameter of the glass filaments is 9 μm or less, processability is further improved, making it possible to realize a thin, high-density printed wiring board. Furthermore, when the average diameter is 3.5 μm or more, breakage of the glass cloth tends to be less likely to occur.

[0041] Examples of elements constituting the glass filaments include Si, B, Al, Ca, Mg, P, Na, K, Ti, Zn, Fe, and F.

[0042] The Si content of the glass yarn, calculated as SiO2, is preferably 40 to 60% by mass, more preferably 45 to 55% by mass, even more preferably 47 to 53% by mass, and even more preferably 48 to 52% by mass. Si is a component that forms the skeletal structure of the glass yarn. When the Si content is 40% by mass or more, the strength of the glass yarn is further improved, and breakage of the glass cloth tends to be further suppressed in the glass cloth manufacturing process and in subsequent processes such as the production of prepregs using the glass cloth. Furthermore, when the Si content is 40% by mass or more, the dielectric constant of the glass cloth tends to be further reduced. On the other hand, when the Si content is 60% by mass or less, the viscosity at the time of melting is further reduced in the glass filament manufacturing process, and glass fibers with a more homogeneous glass composition tend to be obtained. Therefore, the resulting glass filaments are less likely to have parts that are prone to devitrification or parts that are difficult to remove bubbles from. This makes it less likely that the glass filaments will have locally weak parts, and as a result, the glass cloth composed of glass yarns obtained using this will be less likely to break. The Si content can be adjusted depending on the amount of raw material used to prepare the glass filaments.

[0043] The B content of the glass yarn, calculated as B2O3, is preferably 15 to 30 mass%, more preferably 17 to 28 mass%, even more preferably 20 to 27 mass%, still more preferably 21 to 25 mass%, and even more preferably 21.5 to 24 mass%. A B content of 15 mass% or more tends to further reduce the dielectric constant. Furthermore, a B content of 30 mass% or less tends to improve moisture absorption resistance and insulation reliability. The B content can be adjusted depending on the amount of raw material used in producing the glass filaments. Note that if the B content may fluctuate during glass filament production, the amount charged can be adjusted in advance in anticipation of this.

[0044] The Al content of the glass filament is preferably 11 to 18 mass%, more preferably 11 to 16 mass%, and even more preferably 12 to 16 mass%, calculated as Al2O3. When the Al content is within the above range, electrical properties and strength tend to be further improved. The Al content can be adjusted depending on the amount of raw material used to produce the glass filament.

[0045] The Ca content of the glass yarn is preferably 5 to 10 mass %, preferably 5 to 9 mass %, and more preferably 5 to 8.5 mass %, calculated as CaO. When the Ca content is 4 mass % or more, the viscosity at the time of melting tends to be further reduced in the manufacturing process of the glass filament, and glass fibers with a more homogeneous glass composition tend to be obtained. Furthermore, when the Ca content is 10 mass % or less, the dielectric constant tends to be further improved. The Ca content can be adjusted depending on the amount of raw material used in manufacturing the glass filament.

[0046] The above contents can be measured by ICP atomic emission spectroscopy. Specifically, the Si content and B content can be obtained by melting a weighed glass cloth sample with sodium carbonate, dissolving it in dilute nitric acid to a constant volume, and measuring the resulting sample by ICP atomic emission spectroscopy. The Fe content can be obtained by dissolving a weighed glass cloth sample by alkaline dissolution to a constant volume, and measuring the resulting sample by ICP atomic emission spectroscopy. The Al content, Ca content, and Mg content can be obtained by thermally decomposing a weighed glass cloth sample with sulfuric acid, nitric acid, and hydrogen fluoride, dissolving it in dilute nitric acid to a constant volume, and measuring the resulting sample by ICP atomic emission spectroscopy. The ICP atomic emission spectroscopy analyzer can be a PS3520VDD II manufactured by Hitachi High-Tech Science Corporation.

[0047] 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. When the elastic modulus is 50 GPa or more, the rigidity of the glass yarn is improved, and fluffing tends to be less likely to occur during the production process. Furthermore, when the elastic modulus is 70 GPa or less, the brittleness resistance of the glass yarn is improved, and fluffing tends to be less likely to occur during the production process. Furthermore, when the elastic modulus is within the above range, the glass yarn has appropriate flexibility, and when a mechanical load is applied, filament rupture and the like are less likely to occur, and fluffing and weaving defects tend to be less likely to occur.

[0048] The dielectric constant of the obtained glass cloth is preferably 5.0 or less, more preferably 4.8 or less, even more preferably 4.6 or less, and particularly preferably 4.0 or less at a frequency of 1 GHz. The dielectric constant can be measured, for example, by a cavity resonance method. In this embodiment, the dielectric constant refers to the value at a frequency of 1 GHz unless otherwise specified. A glass cloth having a dielectric constant of 5.0 or less at a frequency of 1 GHz is preferred because it can meet the demand for a low dielectric constant.

[0049] The method for producing a glass cloth of this embodiment is not particularly limited as long as it uses the above-mentioned weft yarn, but examples thereof include a yarn width adjusting step of adjusting the yarn width so that the yarn width distribution coefficient of the weft yarn is 0.003 to 0.013 and / or the yarn width variation coefficient is 0.0002 to 0.0015, a weaving step of weaving glass yarns to obtain a glass cloth, and a fiber-opening step of opening the glass yarns of the glass cloth. Furthermore, if necessary, the method may include a desizing step of removing sizing agents adhering to the glass yarns of the glass cloth and a surface treatment step with a silane coupling agent. Each step of this embodiment will be described in more detail below.

[0050] [Thread width adjustment process] The yarn width adjusting step is a step of adjusting the yarn width dispersion coefficient of the weft yarn to be used to be 0.003 or more and 0.013 or less and / or the yarn width distribution variation coefficient A to be 0.0002 or more and 0.0015 or less. More specifically, in the yarn width adjusting step, the yarn width dispersion coefficient and / or yarn width distribution variation coefficient A of the weft yarn are measured, and if the yarn width dispersion coefficient is 0.003 or more and 0.013 or less and / or the yarn width distribution variation coefficient A is 0.0002 or more and 0.0015 or less, the yarn is used in the subsequent weaving step, and if it is outside the range, the yarn is discarded or adjusted by untwisting or untwisting so that the yarn width dispersion coefficient is 0.003 or more and 0.013 or less and / or the yarn width distribution variation coefficient A is 0.0002 or more and 0.0015 or less. Alternatively, it is also possible to provide feedback to the glass yarn manufacturing process and adjust the yarn manufacturing conditions. The width of the glass yarn is affected by variations in the number of twists, such as between high and low twist density areas, and variations in the width of the glass filaments. Therefore, the coefficient of variation of the glass yarn to be used in the weaving process can be adjusted by untwisting or untwisting. Furthermore, if the measurement of the yarn width distribution coefficient and / or yarn width distribution coefficient A of the weft yarn shows that the quality of the glass yarn exceeds the range of the coefficient of variation that can be adjusted by twisting, the glass yarn itself can be replaced as part of the adjustment of the coefficient of variation.

[0051] [Weaving process] The weaving process is a process in which glass yarns are woven to obtain a glass cloth. The weaving method is not particularly limited as long as it weaves weft yarns and warp yarns to form a predetermined weave structure. The weaving structure of the glass cloth is not particularly limited, and examples thereof include plain weave, sash weave, satin weave, twill weave, etc. Among these, a plain weave structure is more preferred.

[0052] FIG. 1 is a perspective view showing one aspect of the weaving process in the manufacturing method of this embodiment. This figure shows one aspect of the weaving process using an air jet loom system. Parallel-pulled warp yarns 1 are opened above and below the opening, and yarns supplied from a weft storage device 2 are sent through the opening by a jet of air from a nozzle 3, resulting in weaving. In this weaving process, it is difficult to send out light weft yarns with a large yarn width variance coefficient and / or yarn width distribution variation coefficient A in a straight line, which can result in fuzz and weaving defects in the resulting glass cloth. In contrast, in this embodiment, we use weft yarns with a yarn width variance coefficient of 0.003 to 0.013 and / or a yarn width distribution variation coefficient A of 0.0002 to 0.0015, as a result of undergoing the yarn width adjustment process described above, thereby suppressing the occurrence of fuzz and weaving defects when the weft yarns are woven. This improves the in-plane 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 a water jet loom method or a shuttle method.

[0053] The pitch density of the warp and weft yarns constituting the glass cloth is preferably 30 to 120 yarns / inch, more preferably 40 to 110 yarns / inch, and even more preferably 50 to 100 yarns / inch. The pitch density of the warp yarns can be controlled by adjusting the interval between the warp yarns drawn in parallel, and the pitch density of the weft yarns can be controlled by the number of jets of the weft yarn from the nozzle per unit time and the flow speed of the warp yarns.

[0054] The thickness of the glass cloth finally obtained after the fiber-opening step etc. is preferably 8 to 100 μm, more preferably 9 to 90 μm, and even more preferably 9.5 to 80 μm. When the thickness of the glass cloth is within the above range, a thin glass cloth with relatively high strength tends to be obtained.

[0055] The fabric weight (basis weight) of the glass cloth is preferably 8 to 250 g / m 2 and more preferably 8 to 130 g / m 2 and more preferably 8 to 100 g / m 2and particularly preferably 8 to 90 g / m 2 is.

[0056] [Opening process] The opening step is a step of opening the glass fibers of the glass cloth. The opening method is not particularly limited, but examples thereof include opening processing using spray water (high-pressure water opening), a vibro washer, ultrasonic water, a mangle, etc.

[0057] [Desizing process] The desizing step is a step of removing the sizing agent attached to the glass yarns of the glass cloth. The desizing method is not particularly limited, but for example, a method of removing the sizing agent by heating can be mentioned.

[0058] [Surface treatment process] The surface treatment step is a step of performing a surface treatment using a silane coupling agent. Examples of the surface treatment method include contacting a surface treatment agent containing a silane coupling agent with glass cloth and drying the resulting mixture. Examples of contacting the glass cloth with the surface treatment agent include immersing the glass cloth in the surface treatment agent, or applying the surface treatment agent to the glass cloth using a roll coater, a die coater, a gravure coater, or the like. The method for drying the surface treatment agent is not particularly limited, and examples thereof include hot air drying and drying using electromagnetic waves.

[0059] (Surface treatment) The glass cloth may be surface-treated with a surface treatment agent. The surface treatment agent is not particularly limited, but examples thereof include a silane coupling agent, and water, an organic solvent, an acid, a dye, a pigment, a surfactant, and the like may be used in combination as needed.

[0060] The silane coupling agent is not particularly limited, but examples thereof include compounds represented by formula (1). X(R) 3-n SiY n ···(1) (In formula (1), X is an organic functional group having at least one of an amino group and an unsaturated double bond group; each Y is independently an alkoxy group; n is an integer of 1 to 3; and each R is independently a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group.)

[0061] X is preferably an organic functional group having at least three or more amino groups and unsaturated double bond groups, and more preferably an organic functional group having at least four or more amino groups and unsaturated double bond groups.

[0062] The alkoxy group may take any form, but from the viewpoint of stabilizing the treatment of glass cloth, an alkoxy group having 5 or less carbon atoms is preferred.

[0063] Specific examples of the silane coupling agent include N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropylmethyldimethoxysilane and its hydrochloride, N-β-(N-di(vinylbenzyl)aminoethyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-di(vinylbenzyl)aminoethyl)-N-γ-(N-vinylbenzyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, and N-β Examples of known simple substances include -(N-benzylaminoethyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-benzylaminoethyl)-γ-aminopropyltriisoethoxysilane and its hydrochloride, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, aminopropyltrimethoxysilane, vinyltrimethoxysilane, methacryloxypropyltrimethoxysilane, and acryloxypropyltrimethoxysilane, or mixtures thereof.

[0064] The molecular weight of the silane coupling agent is preferably 100 to 600, more preferably 150 to 500, and even more preferably 200 to 450. Among these, it is preferable to use two or more silane coupling agents with different molecular weights. By treating the surface of the glass yarn with two or more silane coupling agents with different molecular weights, the density of the surface treatment agent on the surface of the glass cloth tends to increase, and the reactivity with the matrix resin tends to further improve.

[0065] [Other methods for producing glass cloth] In another aspect of the present embodiment, there is provided a method for producing a glass cloth by weaving glass yarns consisting of a plurality of glass filaments as warp yarns and weft yarns, wherein the average number of twists per 25 mm of the weft yarns is 0.50 or more and 1.20 or less, the standard deviation of the number of twists is 0.03 or more and 0.18 or less, and the density of the glass yarns that become the weft yarns is 2.2 g / cm 3 More than 2.5g / cm 3 A manufacturing method in which the temperature is less than 100°C may also be used.

[0066] [Glass thread] The glass yarn of this embodiment is the glass yarn used in the above-mentioned method for producing a glass cloth, particularly the glass yarn used as a weft. The configuration of the glass yarn may be the same as that described above.

[0067] The glass cloth of the present embodiment is obtained by the above-described method for producing a glass cloth, and has the above-described glass yarns at least as weft yarns.

[0068] [Prepreg] The prepreg of this embodiment comprises the glass cloth obtained as described above and a matrix resin composition impregnated into the glass cloth. Prepregs containing the glass cloth have little variation in quality and a high yield of final products. Furthermore, because they have excellent dielectric properties and moisture absorption resistance, they can provide printed wiring boards with little variation in dielectric constant under the influence of the usage environment, particularly in high-humidity environments.

[0069] The prepreg of this embodiment can be produced by a conventional method, for example, by impregnating the glass cloth of this embodiment with a varnish prepared by diluting a matrix resin such as an epoxy resin with an organic solvent, volatilizing the organic solvent in a drying oven, and curing the thermosetting resin to a B-stage state (semi-cured state).

[0070] Examples of the matrix resin composition include, in addition to the above-mentioned epoxy resins, 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, wholly 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.

[0071] The matrix resin composition may also contain inorganic fillers such as silica and aluminum hydroxide; flame retardants such as bromine-based, phosphorus-based, and metal hydroxides; other silane coupling agents; heat stabilizers; antistatic agents; ultraviolet absorbers; pigments; colorants; lubricants; etc.

[0072] [Printed wiring board] The printed wiring board of this embodiment includes the prepreg. A printed wiring board including the prepreg of this embodiment has little variation in quality and a high yield of final products. Furthermore, because the prepreg has excellent dielectric properties and moisture absorption resistance, it also has the effect of minimizing fluctuations in the dielectric constant due to the influence of the usage environment, particularly in high humidity environments. [Example]

[0073] The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to the following examples.

[0074] [Physical properties of glass cloth] The physical properties of the glass cloth, specifically, the thickness of the glass cloth, the diameter of the filaments constituting the warp and weft, the number of filaments, and the weaving density of the warp and weft (weave density) were measured in accordance with JIS R3420.

[0075] [Elastic modulus] The elastic modulus was measured by the pulse-echo overlap method.

[0076] [Composition of glass yarn] The composition of the glass fiber was measured by ICP atomic emission spectroscopy. Specifically, the Si content and B content were obtained by melting a weighed glass cloth sample with sodium carbonate, dissolving it in dilute nitric acid, and measuring the resulting sample by ICP atomic emission spectroscopy. The Fe content was obtained by dissolving a weighed glass cloth sample by an alkaline dissolution method, measuring the resulting sample by ICP atomic emission spectroscopy. The Al content, Ca content, and Mg content were obtained by thermally decomposing a weighed glass cloth sample with sulfuric acid, nitric acid, and hydrogen fluoride, dissolving it in dilute nitric acid, and measuring the resulting sample by ICP atomic emission spectroscopy. The ICP atomic emission spectroscopy analyzer used was a PS3520VDD II manufactured by Hitachi High-Tech Science Corporation.

[0077] [Measurement of standard deviation A and average value of yarn width] While the glass yarn was being transported at a speed of 1 m / min, the width of 50 m of the glass yarn was measured using an LED projection type transmission dimension measuring instrument (HIGH ACCURACY CMOS MICROMETER LS-9006MR / manufactured by Keyence Corporation), and the standard deviation of the glass yarn width (yarn width standard deviation A) and the average value of the yarn width were calculated from the obtained yarn width data.

[0078] The tension acting on the glass yarn as it is transported is measured using a tension meter (SCHMIDT Conrol Instruments ETPB-100-C0585). In Examples 1 to 18, Comparative Example 1, and Reference Examples 1 to 3, the pressure was 0.12 to 0.18 N. In Examples 19 to 29 and Comparative Examples 2 and 3, the pressure was 0.10 to 0.17N. In Examples 30 to 40 and Comparative Examples 4 and 5, the pressure was 0.08 to 0.16 N. In Examples 41 to 48 and Comparative Examples 6 and 7, the pressure was 0.07 to 0.14N. It was.

[0079] [Measurement of yarn width standard deviation B and yarn width distribution standard deviation] The yarn width data of 50 m of glass yarn obtained as described above was divided into 100 equal parts in the length direction, and 100 pieces of yarn width data of the glass yarn were obtained every 0.5 m. Based on this yarn width data of the glass yarn every 0.5 m, the standard deviation (yarn width standard deviation B) was calculated. Then, in order to confirm the variation in the yarn width standard deviation B, the standard deviation was calculated based on the obtained 100 yarn width standard deviations B, and the yarn width distribution standard deviation was obtained.

[0080] [Variation in twist count] The twist count of 50 cm of glass yarn was measured using a twist detector (manufactured by Technos Co., Ltd.) and converted to the twist count per 25 mm. The standard deviation calculated from 30 pieces of twist count data (measured at 10 points on the outer layer side of the bobbin, 10 points in the middle, and 10 points on the inner layer side) was used as the twist count variation.

[0081] [Evaluation 1: Fluff, weaving defects quality] 1000 m of glass cloth was unwound from the glass cloth rolls obtained in the Examples and Comparative Examples, and the presence or absence of fluff and weaving defects was checked, and the quality was evaluated according to the following evaluation criteria. 5: Three or fewer fuzz or weaving defects were found. 4: 3 to 5 fluffs or weaving defects were observed. 3: 6 to 15 fuzz or weaving defects were found. 2: 15 to 30 pieces of fuzz or weaving defects were found. 1: 30 or more pieces of fuzz or weaving defects were found.

[0082] [Evaluation 2: Weaving ability] In the weaving process using the air jet loom in the Examples and Comparative Examples, the number of times weaving stopped during the weaving of 2100 glass cloth was counted, and the weavability was evaluated according to the following evaluation criteria. 5: Stopped 0 times. 4: Stop 1-2 times. 3: Stop 3~4 times. 2: Stop 5-7 times. 1: Stopped 8 times or more.

[0083] [Evaluation 3: Heat resistance] The glass cloth obtained in the examples and comparative examples was impregnated with polyphenylene ether resin varnish, and then the excess varnish was scraped off by passing it through a predetermined slit. The cloth was then dried for a predetermined time in a drying oven at 105°C to remove the toluene, thereby obtaining a prepreg.

[0084] Eight sheets of the resulting prepreg were stacked, and copper foil (FV-WS foil, manufactured by Furukawa Electric Co., Ltd.) with a thickness of 12 μm and a surface roughness of Rz 2.0 μm was placed on both sides of the stack. Then, the stack was heated from room temperature at a temperature increase rate of 3°C / min while applying a pressure of 5 kg / cm. 2 After the temperature reached 130°C, the material was heated at a rate of 3°C / min while applying a pressure of 40 kg / cm. 2 After the temperature reached 200°C, the pressure was increased to 40 kg / cm while maintaining the temperature at 200°C. 2 A copper clad laminate was produced by vacuum pressing under the conditions of 1000 psi and 60 minutes.

[0085] The copper foil on one side was removed by etching, and a heat resistance test was conducted. The test pieces were cut into 50mm squares, placed in a 105°C oven, dried for two hours, and then subjected to a pressure cooker test at two atmospheres for four hours. The heat resistance test was then conducted by dipping the test pieces in a solder bath at 260°C or 288°C for 20 seconds, repeating this test 30 times. The dip intervals were 20 seconds.

[0086] In the heat resistance test, evaluation was carried out by visual observation based on the following criteria. 5: Laminate that showed no blistering, peeling, or whitening at 288°C 3: Laminate that showed no swelling, peeling, or whitening at 260°C (Note that at 288°C, swelling, peeling, or whitening occurred.) 1: Laminate that showed swelling, peeling, or whitening at 260°C

[0087] [Examples 1 to 18, Comparative Example 1, Reference Examples 1 to 3] Glass yarns (average diameter of glass filaments: 5.0 μm, number of filaments: 100) having the composition shown in Table 1 were woven using an air jet loom to obtain glass cloth with a warp pick density of 65 / 25 mm, a weft pick density of 67 / 25 mm, and a thickness of 30 μm. Next, a desizing treatment was performed by heating, and a fiber-opening process was carried out using a high-pressure water spray, followed by a surface treatment using a silane coupling agent to produce glass cloth. Similarly, glass cloths were produced using E-glass as Reference Examples 1 to 3.

[0088] [Examples 19 to 29, Comparative Examples 2 and 3] Glass yarns (average diameter of glass filaments: 5.0 μm, number of filaments: 200) having the composition shown in Table 2 were woven to obtain glass cloth with a warp and weft density of 52.5 / 25 mm and a thickness of 45 μm.

[0089] [Examples 30 to 40, Comparative Examples 4 and 5] Glass yarns (average diameter of glass filaments: 6.0 μm, number of filaments: 200) having the composition shown in Table 2 were woven to obtain glass cloth with a warp density of 59 / 25 mm, a weft density of 61 / 25 mm, and a thickness of 70 μm.

[0090] [Examples 41 to 48, Comparative Examples 6 and 7] Glass yarns (average diameter of glass filaments: 7.0 μm, number of filaments: 200) having the composition shown in Table 2 were woven to obtain a glass cloth with a warp density of 60 / 25 mm, a weft density of 57 / 25 mm, and a thickness of 88 μm.

[0091] [Table 1]

[0092] [Table 2]

[0093] [Table 3]

[0094] [Table 4] [Industrial Applicability]

[0095] INDUSTRIAL APPLICABILITY The present invention has industrial applicability as a method for producing glass cloth used for prepregs and the like.

Claims

1. A method for producing a glass cloth, which is woven using glass yarns made of a plurality of glass filaments as warp yarns and weft yarns, comprising: The density of the glass yarn that becomes the weft yarn is 2.2 g / cm 3 Above, 2.5g / cm 3 is less than The yarn width dispersion coefficient indicating the yarn width variation of the glass yarn that becomes the weft yarn is 0.003 or more and 0.013 or less, and / or The yarn width distribution variation coefficient A, which indicates the yarn width distribution variation of the glass yarn that becomes the weft yarn, is 0.0002 or more and 0.0015 or less. Glass cloth manufacturing method. Yarn width dispersion coefficient = Value obtained by dividing the standard deviation of the yarn width (yarn width standard deviation A) by the average diameter of the glass filaments Coefficient of variation of yarn width distribution A = Value obtained by dividing the standard deviation of yarn width standard deviation B (yarn width distribution standard deviation) when determining the standard deviation of yarn width (yarn width standard deviation B) for every 0.5 m length by the diameter of the glass filaments that make up the weft yarn

2. The density of the glass yarn is 2.2 g / cm 3 Excess, 2.5g / cm 3 is less than The yarn width dispersion coefficient is more than 0.003 and less than 0.010, And / or the yarn width distribution variation coefficient A is more than 0.0003 and less than 0.0012, The method for producing the glass cloth according to claim 1.

3. The yarn width distribution coefficient is 0.005 or more and 0.013 or less, The yarn width distribution variation coefficient A is 0.0006 or more and 0.0015 or less, And / or, the yarn width distribution variation coefficient B, which indicates the yarn width distribution variation of the glass yarn that becomes the weft yarn, is 0.013 or more and 0.027 or less; The method for producing the glass cloth according to claim 1. Coefficient of variation of yarn width distribution B = A value obtained by dividing the yarn width distribution CV value, which is obtained by dividing the standard deviation of yarn width standard deviation B (yarn width distribution standard deviation) by the average value of yarn width standard deviation B when the standard deviation of yarn width (yarn width standard deviation B) is calculated for each 0.5 m length, by the diameter of the glass filaments constituting the weft yarn.

4. The average number of twists per 25 mm of the weft is 0.50 or more and 1.20 or less, The standard deviation indicating the variation in the number of twists is 0.10 or more and 0.20 or less. The method for producing glass cloth according to any one of claims 1 to 3.

5. the weft is a glass yarn formed by bundling 80 to 120 glass filaments having an average diameter of more than 4.5 μm and not more than 5.5 μm, and the average yarn width of the glass yarn is 90 μm to 130 μm; The method for producing the glass cloth according to any one of claims 1 to 4.

6. the weft is a glass yarn formed by bundling 180 to 220 glass filaments having an average diameter of more than 4.5 μm and not more than 5.5 μm, and the average yarn width of the glass yarn is 120 μm to 175 μm; The method for producing the glass cloth according to any one of claims 1 to 4.

7. the weft is a glass yarn formed by bundling 180 to 220 glass filaments having an average diameter of more than 5.5 μm and not more than 6.5 μm, and the average yarn width of the glass yarn is 155 μm to 195 μm; The method for producing the glass cloth according to any one of claims 1 to 4.

8. the weft is a glass yarn formed by bundling 180 to 220 glass filaments having an average diameter of more than 6.5 μm and not more than 7.5 μm, and the average yarn width of the glass yarn is 180 μm to 220 μm; The method for producing the glass cloth according to any one of claims 1 to 4.

9. The elastic modulus of the glass yarn is 50 to 70 GPa. The method for producing glass cloth according to any one of claims 1 to 8.

10. The elastic modulus of the glass yarn is 50 to 63 GPa. The method for producing glass cloth according to claim 9.

11. The glass cloth has a dielectric constant of 5.0 or less at a frequency of 1 GHz. The method for producing glass cloth according to any one of claims 1 to 10.

12. The glass yarn, The Si content is 40 to 60 mass% in terms of SiO2, The B content is 15 to 30 mass% in terms of B2O3. The method for producing glass cloth according to any one of claims 1 to 11.

13. The density is 2.2 g / cm or more and less than 2.5 g / cm, The yarn width dispersion coefficient, which indicates the yarn width variation, is 0.003 or more and 0.013 or less, and / or The yarn width distribution variation coefficient A, which indicates the distribution variation of the yarn width, is 0.0002 or more and 0.0015 or less; Glass thread. Yarn width dispersion coefficient = Value obtained by dividing the standard deviation of the yarn width (yarn width standard deviation A) by the average diameter of the glass filaments Coefficient of variation of yarn width distribution A = Value obtained by dividing the standard deviation of yarn width standard deviation B (yarn width distribution standard deviation) when determining the standard deviation of yarn width (yarn width standard deviation B) for every 0.5 m length by the diameter of the glass filaments that make up the weft yarn

14. The density of the glass yarn is 2.2 g / cm 3 Excess, 2.5g / cm 3 is less than The yarn width dispersion coefficient is more than 0.003 and less than 0.010, And / or the yarn width distribution variation coefficient A is more than 0.0003 and less than 0.0012, The glass thread according to claim 13.

15. The yarn width distribution coefficient is 0.005 or more and 0.013 or less, The yarn width distribution variation coefficient A is 0.0006 or more and 0.0015 or less, And / or, the yarn width distribution variation coefficient B, which indicates the yarn width distribution variation of the glass yarn that becomes the weft yarn, is 0.013 or more and 0.027 or less; The glass thread according to claim 13. Coefficient of variation of yarn width distribution B = A value obtained by dividing the yarn width distribution CV value, which is obtained by dividing the standard deviation of yarn width standard deviation B (yarn width distribution standard deviation) by the average value of yarn width standard deviation B when the standard deviation of yarn width (yarn width standard deviation B) is calculated for each 0.5 m length, by the diameter of the glass filaments constituting the weft yarn.

16. The average number of twists per 25 mm is 0.50 or more and 1.20 or less, The standard deviation indicating the variation in the number of twists is 0.10 or more and 0.20 or less. The glass fiber according to any one of claims 13 to 15.

17. The glass yarn is a bundle of 80 to 120 glass filaments having an average diameter of more than 4.5 μm and not more than 5.5 μm, and the average yarn width is 90 μm to 130 μm. The glass filament according to any one of claims 13 to 16.

18. The glass yarn is a bundle of 180 to 220 glass filaments having an average diameter of more than 4.5 μm and not more than 5.5 μm, and the average yarn width is 120 μm to 175 μm. The glass filament according to any one of claims 13 to 16.

19. The glass yarn is a bundle of 180 to 220 glass filaments having an average diameter of more than 5.5 μm and not more than 6.5 μm, and the average yarn width is 155 μm to 195 μm. The glass filament according to any one of claims 13 to 16.

20. The glass yarn is a bundle of 180 to 220 glass filaments having an average diameter of more than 6.5 μm and not more than 7.5 μm, and the average yarn width is 180 μm to 220 μm. The glass filament according to any one of claims 13 to 16.

21. The elastic modulus is 50 to 70 GPa. The glass fiber according to any one of claims 13 to 20.

22. The elastic modulus is 50 to 63 GPa. The glass fiber according to any one of claims 13 to 20.

23. having a dielectric constant of 5.0 or less at a frequency of 1 GHz; The glass filament according to any one of claims 13 to 22.

24. The Si content is 40 to 60 mass% in terms of SiO2, The B content is 15 to 30 mass% in terms of B2O3. The glass fiber according to any one of claims 13 to 23.

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