Glass cloth, prepreg, and printed wiring boards

Abstract

An object of the present disclosure is to provide a glass cloth that can improve skew in printed wiring boards and has excellent productivity and resin impregnation properties. [Solution] This disclosure provides a glass cloth constructed with warp and weft yarns made of glass yarns consisting of a plurality of glass filaments. The glass cloth has a thickness in the range of 26 to 36 μm, with warp and weft widths in the ranges of 211 to 300 μm and 326 to 400 μm, respectively, or a thickness in the range of 42 to 58 μm, with warp and weft widths in the ranges of 267 to 385 μm and 425 to 550 μm, respectively. The coefficient of variation of the dielectric constant of the glass cloth at 10 GHz, measured using a split cylinder resonator, is 8.0% or less.

Description

[Technical Field]

[0001] The present disclosure relates to a glass cloth, a prepreg, and a printed wiring board. [Background technology]

[0002] Currently, with the increasing performance of information terminals such as smartphones and the trend toward high-speed communications typified by 5G communications, there has been a significant trend toward lowering the dielectric constant and dielectric loss tangent of insulating materials used in printed wiring boards for high-speed communications to reduce transmission loss.

[0003] Currently, the performance of information terminals such as smartphones is improving, and high-speed communications, exemplified by 5G communications, are advancing. Against this background, for example, further improvements in heat resistance and insulation reliability are required for printed wiring boards used in high-speed communications. Furthermore, as the wiring patterns of printed wiring boards become increasingly finer, there is a strong demand for improvements in the delay (skew) of propagation signals that occurs due to differences in the distribution of the matrix resin and glass cloth in printed wiring boards.

[0004] Various efforts have been made to improve skew, and Patent Document 1 discloses a prepreg that is effective in reducing skew. Furthermore, as an example of further improvement in skew, Patent Document 2, for example, reports that skew in printed wiring boards is improved by processing glass cloth while untwisting glass yarns. Patent Document 3 reports that skew is improved by dispersing hexagonal boron nitride in a matrix resin. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2013 / 140812 [Patent Document 2] International Publication No. 2023 / 238763 [Patent Document 3] Japanese Patent Application Laid-Open No. 2017-170748 Summary of the Invention [Problem to be solved by the invention]

[0006] However, even in Patent Documents 1 to 3, there is room for further improvement in skew in the glass cloth. Furthermore, for example, in Patent Document 2, the glass yarn is untwisted, which easily generates fluff in the glass cloth, which is likely to reduce the productivity of the prepreg. Furthermore, from the viewpoint of suppressing voids in the prepreg, a glass cloth with high resin impregnation is desired. Therefore, an object of the present disclosure is to provide a glass cloth that can improve skew in printed wiring boards and has excellent productivity and resin impregnation. [Means for solving the problem]

[0007] Some aspects of the present disclosure are illustrated below. [1] A glass cloth constructed by using glass yarns made of a plurality of glass filaments as warp yarns and weft yarns, The thickness of the glass cloth is in the range of 26 to 36 μm, The warp width and weft width of the glass cloth are in the ranges of 211 to 300 μm and 326 to 400 μm, respectively; The glass cloth has a coefficient of variation of dielectric constant of 8.0% or less at 10 GHz, as measured using a split cylinder resonator. [2] A glass cloth constructed by using glass yarns made of a plurality of glass filaments as warp yarns and weft yarns, The thickness of the glass cloth is in the range of 42 to 58 μm, The warp width and weft width of the glass cloth are in the ranges of 267 to 385 μm and 425 to 550 μm, respectively; The glass cloth has a coefficient of variation of dielectric constant of 8.0% or less at 10 GHz, as measured using a split cylinder resonator. [3] A glass cloth constructed by using glass yarns made of a plurality of glass filaments as warp yarns and weft yarns, The thickness of the glass cloth is in the range of 13 to 19 μm, The warp width and weft width of the glass cloth are in the ranges of 125 to 135 μm and 200 to 240 μm, respectively; The glass cloth has a coefficient of variation of dielectric constant of 8.0% or less at 10 GHz, as measured using a split cylinder resonator. [4] A glass cloth constructed by using glass yarns made of a plurality of glass filaments as warp yarns and weft yarns, The thickness of the glass cloth is in the range of 17 to 25 μm, The warp width and weft width of the glass cloth are in the ranges of 178 to 198 μm and 310 to 342 μm, respectively; The glass cloth has a coefficient of variation of dielectric constant of 8.0% or less at 10 GHz, as measured using a split cylinder resonator. [5] A glass cloth constructed by using glass yarns made of a plurality of glass filaments as warp yarns and weft yarns, The thickness of the glass cloth is in the range of 20 to 30 μm, The warp width and weft width of the glass cloth are in the ranges of 176 to 232 μm and 329 to 353 μm, respectively; The glass cloth has a coefficient of variation of dielectric constant of 8.0% or less at 10 GHz, as measured using a split cylinder resonator. [6] 6. The glass cloth according to any one of items 1 to 5, wherein the dielectric constant is in the range of 3.8 to 4.5. [7] 7. The glass cloth according to any one of items 1 to 6, wherein the glass fibers contain, in oxide equivalents based on the total mass of the glass fibers, 45 to 55 mass% of SiO, 17 to 27 mass% of BO, 11 to 21 mass% of AlO, 2.7 to 5.7 mass% in total of CaO and MgO, and 0 to 0.15 mass% in total of LiO, KO, and NaO. [8] 8. The glass cloth according to item 7, wherein the glass yarn contains, in oxide equivalents, 0.15 to 0.45 mass% of TiO, 2.5 to 7.5 mass% of PO, and 0 to 0.02 mass% of SrO, based on the total mass of the glass yarn. [9] 7. The glass cloth according to any one of items 1 to 6, wherein the glass yarn contains, in oxide equivalents based on the total mass of the glass yarn, 48 to 58 mass% of SiO, 18 to 28 mass% of BO, 8 to 18 mass% of AlO, 3.4 to 6.4 mass% in total of CaO and MgO, and 0 to 0.15 mass% in total of LiO, KO, and NaO.

[10] Item 10. The glass cloth according to item 9, wherein the glass yarn contains, in oxide equivalents, 0.9 to 2.9 mass% of TiO, 0 to 0.03 mass% of PO, and 0 to 3 mass% of SrO, based on the total mass of the glass yarn.

[11] 7. The glass cloth according to any one of items 1 to 6, wherein the glass yarn contains, in oxide equivalents based on the total mass of the glass yarn, 48 to 58 mass% of SiO, 17 to 27 mass% of BO, 11 to 21 mass% of AlO, 3.5 to 6.5 mass% in total of CaO and MgO, and 0 to 0.1 mass% in total of LiO, KO, and NaO.

[12] Item 12. The glass cloth according to item 11, wherein the glass yarn contains, in oxide equivalents, 0 to 0.3 mass% of TiO, 0 to 4.2 mass% of PO, and 0 to 1 mass% of SrO, based on the total mass of the glass yarn.

[13] 7. The glass cloth according to any one of items 1 to 6, wherein the glass yarn contains, in oxide equivalents based on the total mass of the glass yarn, 47 to 57 mass% of SiO, 22 to 32 mass% of BO, 8 to 18 mass% of AlO, 1.4 to 4.4 mass% in total of CaO and MgO, and 0.1 to 1.0 mass% in total of LiO, KO, and NaO.

[14] Item 14. The glass cloth according to item 13, wherein the glass yarn contains, in oxide equivalents, 0 to 1 mass % of TiO, 0 to 0.2 mass % of PO, and 0 to 0.3 mass % of SrO, based on the total mass of the glass yarn.

[15] 7. The glass cloth according to any one of items 1 to 6, wherein the glass yarn contains, in oxide equivalents based on the total mass of the glass yarn, 47 to 57 mass% of SiO, 18 to 28 mass% of BO, 9 to 19 mass% of AlO, 3.4 to 6.4 mass% in total of CaO and MgO, and 0 to 0.3 mass% in total of LiO, KO, and NaO.

[16] Item 16. The glass cloth according to item 15, wherein the glass yarn contains, in oxide equivalents, 0.01 to 0.3 mass% of TiO, 0 to 0.2 mass% of PO, and 0 to 0.3 mass% of SrO, based on the total mass of the glass yarn.

[17] 7. The glass cloth according to any one of items 1 to 6, wherein the glass yarn contains, in oxide equivalents based on the total mass of the glass yarn, 47 to 57 mass% of SiO, 20 to 30 mass% of BO, 8 to 18 mass% of AlO, 3.0 to 7.0 mass% in total of CaO and MgO, and 0 to 0.3 mass% in total of LiO, KO, and NaO.

[18] Item 18. The glass cloth according to item 17, wherein the glass yarn contains, in oxide equivalents, 1.0 to 5.0 mass% of TiO, 0 to 0.1 mass% of PO, and 0 to 0.2 mass% of SrO, based on the total mass of the glass yarn.

[19] Item 7. The glass cloth according to item 6, wherein the dielectric constant is in the range of 4.0 to 4.3.

[20] 7. The glass cloth according to any one of items 1 to 6, wherein the glass cloth has a dielectric loss tangent of 0.0025 or less at 10 GHz, as measured using a split cylinder resonator. [twenty one] 7. The glass cloth according to any one of items 1 to 6, wherein the glass cloth has a dielectric loss tangent of 0.0023 or less at 10 GHz, as measured using a split cylinder resonator. [twenty two] 7. The glass cloth according to any one of items 1 to 6, wherein the glass cloth has a dielectric loss tangent of 0.0020 or less at 10 GHz, as measured using a split cylinder resonator. [twenty three] 7. The glass cloth according to any one of items 1 to 6, wherein the glass cloth has a dielectric loss tangent at 10 GHz measured using a split cylinder resonator in the range of 0.0010 to 0.0018. [twenty four] 7. The glass cloth according to any one of items 1 to 6, wherein the dielectric loss tangent of the glass cloth at 10 GHz measured using a split cylinder resonator is in the range of 0.0018 to 0.0020. [twenty five] 7. The glass cloth according to any one of items 1 to 6, wherein the coefficient of variation of the dielectric constant is 6.0% or less.

[26] 7. The glass cloth according to any one of items 1 to 6, wherein the coefficient of variation of the dielectric constant is 4.0% or less.

[27] 7. The glass cloth according to any one of items 1 to 6, wherein the coefficient of variation of the dielectric constant is 2.0% or less.

[28] Item 2. The glass cloth according to item 1, wherein the warp width and weft width of the glass cloth are in the ranges of 213 to 290 μm and 335 to 390 μm, respectively.

[29] Item 2. The glass cloth according to item 1, wherein the warp width and weft width of the glass cloth are in the ranges of 215 to 275 μm and 345 to 380 μm, respectively.

[30] Item 2. The glass cloth according to item 1, wherein the warp width and weft width of the glass cloth are in the ranges of 218 to 260 μm and 350 to 375 μm, respectively.

[31] Item 2. The glass cloth according to item 1, wherein the standard deviations of the warp width and the weft width of the glass cloth are in the ranges of 16 μm or less and 34 μm or less, respectively.

[32] Item 3. The glass cloth according to item 2, wherein the warp width and weft width of the glass cloth are in the ranges of 270 to 370 μm and 440 to 540 μm, respectively.

[33] Item 3. The glass cloth according to item 2, wherein the warp width and weft width of the glass cloth are in the ranges of 275 to 360 μm and 450 to 530 μm, respectively.

[34] Item 3. The glass cloth according to item 2, wherein the warp width and weft width of the glass cloth are in the ranges of 285 to 350 μm and 460 to 500 μm, respectively.

[35] Item 3. The glass cloth according to item 2, wherein the standard deviations of the warp width and the weft width of the glass cloth are 26 μm or less and 39 μm or less, respectively.

[36] Item 4. The glass cloth according to item 3, wherein the warp width and weft width of the glass cloth are in the ranges of 126 to 134 μm and 204 to 236 μm, respectively.

[37] Item 4. The glass cloth according to item 3, wherein the warp width and weft width of the glass cloth are in the ranges of 127 to 133 μm and 208 to 232 μm, respectively.

[38] Item 4. The glass cloth according to item 3, wherein the standard deviations of the warp width and the weft width of the glass cloth are in the ranges of 15 μm or less and 24 μm or less, respectively.

[39] Item 5. The glass cloth according to item 4, wherein the warp width and weft width of the glass cloth are in the ranges of 180 to 196 μm and 313 to 339 μm, respectively.

[40] Item 5. The glass cloth according to item 4, wherein the warp width and weft width of the glass cloth are in the ranges of 182 to 194 μm and 316 to 336 μm, respectively.

[41] Item 5. The glass cloth according to item 4, wherein the standard deviations of the warp width and the weft width of the glass cloth are in the ranges of 20 μm or less and 40 μm or less, respectively.

[42] Item 6. The glass cloth according to item 5, wherein the warp width and weft width of the glass cloth are in the ranges of 183 to 225 μm and 332 to 350 μm, respectively.

[43] Item 6. The glass cloth according to item 5, wherein the warp width and weft width of the glass cloth are in the ranges of 190 to 218 μm and 335 to 347 μm, respectively.

[44] Item 6. The glass cloth according to item 5, wherein the standard deviations of the warp width and the weft width of the glass cloth are in the ranges of 20 μm or less and 43 μm or less, respectively.

[45] 45. The glass cloth according to any one of items 1 to 44, wherein the coefficient of variation of TEX of the glass yarn is 4.0% or less.

[46] 45. The glass cloth according to any one of items 1 to 44, wherein the coefficient of variation of TEX of the glass yarn is 3.0% or less.

[47] A prepreg comprising the glass cloth according to any one of items 1 to 46 and a matrix resin.

[48] Item 48. A printed wiring board comprising the prepreg according to item 47.

[49] Item 49. An integrated circuit comprising the printed wiring board according to item 48.

[50] Item 49. An electronic device comprising the printed wiring board according to item 48. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a glass cloth that can improve skew in a printed wiring board and has excellent productivity and resin impregnation properties. DETAILED DESCRIPTION OF THE INVENTION

[0009] Examples of embodiments of the present disclosure will be described below, but the present disclosure is not limited thereto and various modifications are possible without departing from the spirit of the present disclosure. In the present disclosure, a numerical range described using "to" indicates a numerical range that includes the numerical values ​​before and after "to" as the upper and lower limits. In the present disclosure, in a numerical range described in stages, the upper or lower limit described in a certain numerical range can be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in the present disclosure, the upper or lower limit described in a certain numerical range can also be replaced with a value shown in the examples. In the present disclosure, the term "process" refers not only to an independent process, but also to a process that cannot be clearly distinguished from other processes, as long as the function of the process is achieved.

[0010] Glass cloth The glass cloth of the present disclosure is a glass cloth configured with glass yarns consisting of a plurality of glass filaments as warp and weft. Examples of the weave structure of the glass cloth include plain weave, sash weave, satin weave, and twill weave. Among these, plain weave structures are preferred.

[0011] [Dielectric tangent and dielectric constant of glass cloth] The glass cloth preferably has a dielectric loss tangent (Df) at 10 GHz measured using a split cylinder resonator of 0.0025 or less. When the dielectric loss tangent of the glass cloth is within the above range, transmission loss in printed wiring boards can be reduced, facilitating high-speed signal communication. From the viewpoint of easily achieving the effect of reducing transmission loss, the dielectric loss tangent of the glass cloth is more preferably 0.0023 or less, even more preferably 0.0021 or less, particularly preferably 0.0020 or less, and may be 0.0019 or less, or 0.0018 or less. There is no particular restriction on the lower limit of the dielectric loss tangent, but it is preferably 0.0010 or more, and more preferably in the range of 0.0010 to 0.0018. Furthermore, from the viewpoint of easily achieving a high yield of glass yarn, fluff quality, and a low dielectric loss tangent when made into glass cloth, the dielectric loss tangent of the glass cloth is preferably in the range of 0.0017 to 0.0020, and more preferably in the range of 0.0018 to 0.0020. The dielectric constant (Dk) of the glass cloth is preferably in the range of 3.8 to 4.5, more preferably in the range of 4.0 to 4.3, from the viewpoint of reducing the difference in dielectric constant with the matrix resin and facilitating improvement of skew performance. The dielectric loss tangent and dielectric constant of the glass cloth are measured by the methods described in the Examples.

[0012] [Glass Cloth Cloth Type P] The glass cloth of the present disclosure has a thickness in the range of 26 to 36 μm, a warp width and a weft width in the range of 211 to 300 μm and 326 to 400 μm, respectively (also referred to as "Cloth Type P" in the present disclosure), and the coefficient of variation of the dielectric constant of the glass cloth at 10 GHz, measured using a split cylinder resonator, is in the range of 8.0% or less.

[0013] The glass cloth (Cloth Type P) of the present disclosure, having the above-described configuration, can provide a glass cloth with excellent skew characteristics and is also excellent in productivity and resin impregnation. The reason for this is presumed, without being limited by theory, as follows: A printed wiring board has a copper foil pattern for transmitting and receiving electrical signals on the surface of a laminate composed of a matrix resin and a glass cloth. The surface of the glass cloth is discontinuous, with voids filled with the matrix resin and glass threads intermingled, and the glass cloth and matrix resin have different dielectric constants, which mainly result in differences in signal speed between the matrix resin and the glass threads (commonly referred to as "skew"). Therefore, to improve skew using glass cloth, it is effective to increase the width of the glass cloth to make the surface of the glass cloth more uniform. Increasing the width of the glass cloth also improves resin impregnation. Printed wiring boards are made from prepregs obtained by impregnating glass cloth with a resin composition and then semi-curing the impregnated glass cloth. Using glass cloth with high resin impregnation properties reduces the occurrence of voids (commonly called voids) in the prepreg and printed wiring board, improving insulation reliability. Furthermore, excellent resin impregnation properties also improve the heat resistance of printed wiring boards and other components. A common method for widening the yarn width of glass cloth is to open the glass cloth. However, opening the glass cloth to widen the yarn width causes fluffing on the surface of the glass cloth, leading to reduced productivity. In other words, there is a trade-off between improving skew and resin impregnation properties and productivity (fluff quality). After extensive research, the inventors discovered that by designing the thickness, warp width, and weft width of the glass cloth within appropriate ranges, the yarn width can be sufficiently opened without applying strong opening processing to the glass cloth.Specifically, when the warp width and weft width of the glass cloth are within the ranges of 211 to 300 μm and 326 to 400 μm, respectively, a glass cloth thickness of 26 μm or more eliminates the need to excessively widen the glass cloth's thread width and eliminates the need for strong opening processing of the glass cloth, thereby improving the fluff quality of the glass cloth and leading to increased productivity. On the other hand, a glass cloth thickness of 36 μm or less allows the thread width to be sufficiently opened, improving skew and resin impregnation. Furthermore, since very fine patterns are formed on printed wiring boards using low-dielectric glass cloth, there is a demand for improved skew characteristics of the glass cloth more than ever before. Therefore, the inventors have conducted research and found that the skew characteristics of printed wiring boards can be significantly improved by setting the thickness, warp width, and weft width of the glass cloth within the above ranges and, in addition, setting the coefficient of variation of the dielectric constant of the glass cloth at 10 GHz, measured using a split cylinder resonator, to 8.0% or less. The reason for this is that skew characteristics have traditionally been thought to be a phenomenon caused by the difference in dielectric constant between the glass cloth and the matrix resin. However, the inventors discovered that the skew characteristics are also affected by the large variation in dielectric constant within the glass cloth plane caused by the variation in elements such as boron, which are easily volatilized by heating, within the glass cloth plane during the thermal deoiling process. Therefore, the inventors conceived the idea of ​​reducing the variation in dielectric constant within the glass cloth plane to reduce the difference in skew performance not only between the glass cloth and the matrix resin but also between glass cloths themselves. As a result of extensive research, as described below, by processing the glass cloth to achieve a more uniform glass composition within the plane, the variation in dielectric constant within the glass cloth plane was reduced, leading to a significant improvement in the skew performance of printed wiring boards. As a result, a glass cloth can be obtained that achieves high productivity, skew characteristics, and resin impregnation properties.

[0014] The thickness of the glass cloth (cloth type P) is in the range of 26 to 36 μm, preferably in the range of 27 to 35 μm, more preferably in the range of 28 to 34 μm, further preferably in the range of 29 to 33 μm, and particularly preferably in the range of 30 to 32 μm. When the thickness of the glass cloth is in the above range, it is possible to obtain a glass cloth that achieves a high level of productivity, skew characteristics, and resin impregnation properties.

[0015] The warp width and weft width of the glass cloth (cross type P) are in the ranges of 211 to 300 μm and 326 to 400 μm, respectively, preferably 213 to 290 μm and 335 to 390 μm, respectively, more preferably 215 to 275 μm and 345 to 380 μm, respectively, and particularly preferably 218 to 260 μm and 350 to 375 μm, respectively. Alternatively, the warp width and weft width of the glass cloth (cross type P) may be in the ranges of 211 to 280 μm and 326 to 400 μm, respectively, 215 to 270 μm and 335 to 390 μm, respectively, 220 to 260 μm and 345 to 380 μm, respectively, or 225 to 250 μm and 350 to 375 μm, respectively. When the warp width and weft width of the glass cloth are within the above ranges, a glass cloth can be obtained that achieves both high productivity and excellent skew characteristics.

[0016] The standard deviations of the warp width and weft width of the glass cloth (Cloth Type P) are preferably 16 μm or less and 34 μm or less, respectively. If the standard deviation of the width is within the above range, the effect of improving the skew characteristics of the glass cloth can be easily obtained. From the viewpoint of more easily obtaining the effect of improving the skew characteristics, the standard deviations of the warp width and weft width of the glass cloth are more preferably 15 μm or less and 33 μm or less, even more preferably 14 μm or less and 32 μm or less, and particularly preferably 13 μm or less and 31 μm or less. The standard deviation of the width can be reduced, for example, by performing an opening treatment to widen the width of the glass cloth. After surface treatment with a silane coupling agent, it is preferable to perform an opening treatment using a high-pressure spray or the like. After thermal deoiling treatment, it is more preferable to simultaneously treat the glass cloth with ultrasonic waves in water to eliminate adhesion between the glass filaments. The lower limits of the standard deviations of the warp width and weft width are not limited, but may be, for example, 5 μm or more and 10 μm or more, respectively.

[0017] The glass cloth (Cloth Type P) has a coefficient of variation of the dielectric constant at 10 GHz measured using a split cylinder resonator in the range of 8.0% or less. As a result of studies conducted by the present inventors, as described below, it has been found that by controlling the amount of Na ions and Mg ions attached to the surface of the glass cloth and adjusting the conditions for thermal deoiling, it is possible to suppress the compositional variation of the glass yarns and reduce the coefficient of variation of the dielectric constant of the glass cloth to 8.0% or less. From the viewpoint of easily achieving an improvement in skew characteristics, the coefficient of variation of the dielectric constant of the glass cloth is preferably in the range of 6.0% or less, more preferably in the range of 4.0% or less, and particularly preferably in the range of 2.0% or less. The lower limit of the coefficient of variation of the dielectric constant is not limited, but may be greater than 0%, for example, 1.0% or more.

[0018] The pitch density of the warp and weft yarns constituting the glass cloth (cloth type P) is preferably 55 to 75 yarns / 25 mm, more preferably 57 to 73 yarns / 25 mm, even more preferably 59 to 71 yarns / 25 mm, and particularly preferably 61 to 73 yarns / 25 mm. If the pitch density is within the above range, a glass cloth can be obtained that achieves a high level of productivity, skew characteristics, and resin impregnation. The pitch densities of the warp and weft yarns may be the same or different.

[0019] [Glass Cloth Cloth Type Q] Another embodiment of the glass cloth of the present disclosure is a glass cloth having a thickness in the range of 42 to 58 μm, a warp width and a weft width in the range of 267 to 385 μm and 425 to 550 μm, respectively (also referred to as "Cloth Type Q" in the present disclosure), and a coefficient of variation of the dielectric constant of the glass cloth at 10 GHz measured using a split cylinder resonator in the range of 8.0% or less.

[0020] The glass cloth (Cloth Type Q) of the present disclosure, having the above-described configuration, can provide a glass cloth with excellent skew characteristics, and is also excellent in productivity and resin impregnation. The reasons for this are the same as those for the above-described Cloth Type P, except that the thickness of the glass cloth and the appropriate ranges of the warp width and weft width are different.

[0021] The thickness of the glass cloth (Cloth Type Q) is in the range of 42 to 58 μm, preferably in the range of 43 to 57 μm, more preferably in the range of 44 to 56 μm, further preferably in the range of 45 to 55 μm, and particularly preferably in the range of 46 to 53 μm. When the thickness of the glass cloth is in the above range, it is possible to obtain a glass cloth that achieves a high degree of compatibility between productivity, skew characteristics, and resin impregnation properties.

[0022] The warp width and weft width of the glass cloth (cloth type Q) are in the ranges of 267 to 385 μm and 425 to 550 μm, respectively, preferably 270 to 370 μm and 440 to 540 μm, respectively, more preferably 275 to 360 μm and 450 to 530 μm, respectively, and particularly preferably 285 to 350 μm and 460 to 500 μm, respectively. Alternatively, the warp width and weft width of the glass cloth (cloth type Q) may be in the ranges of 267 to 350 μm and 425 to 550 μm, respectively, 280 to 340 μm and 440 to 540 μm, respectively, 285 to 330 μm and 450 to 530 μm, respectively, or 290 to 320 μm and 460 to 500 μm, respectively. When the warp width and weft width of the glass cloth are within the above ranges, a glass cloth can be obtained that has a higher degree of compatibility between productivity, skew characteristics, and resin impregnation properties.

[0023] The standard deviations of the warp width and weft width of the glass cloth (Cloth Type Q) are preferably in the ranges of 26 μm or less and 39 μm or less, respectively. If the standard deviation of the yarn width is within the above range, the effect of improving the skew characteristics of the glass cloth can be easily obtained. From the viewpoint of more easily obtaining the effect of improving the skew characteristics, the standard deviations of the warp width and weft width of the glass cloth are more preferably in the ranges of 25 μm or less and 38 μm or less, even more preferably in the ranges of 24 μm or less and 37 μm or less, and particularly preferably in the ranges of 23 μm or less and 36 μm or less. The adjustment of the standard deviation of the yarn width is the same as for Cross Type P. The lower limits of the standard deviations of the warp width and weft width are not limited, but may be, for example, 10 μm or more and 20 μm or more, respectively.

[0024] The glass cloth (Cloth Type Q) has a coefficient of variation of the dielectric constant at 10 GHz measured using a split cylinder resonator in the range of 8.0% or less. As a result of studies conducted by the present inventors, as described below, it has been found that by controlling the amount of Na ions and Mg ions attached to the surface of the glass cloth and adjusting the conditions for thermal deoiling, it is possible to suppress the compositional variation of the glass yarns and reduce the coefficient of variation of the dielectric constant of the glass cloth to 8.0% or less. From the viewpoint of easily achieving an improvement in skew characteristics, the coefficient of variation of the dielectric constant of the glass cloth is preferably in the range of 6.0% or less, more preferably in the range of 4.0% or less, and particularly preferably in the range of 2.0% or less. The lower limit of the coefficient of variation of the dielectric constant is not limited, but may be greater than 0%, for example, 1.0% or more.

[0025] The placement density of the warp and weft yarns constituting the glass cloth (Cloth Type Q) is preferably 43 to 63 yarns / 25 mm, more preferably 45 to 61 yarns / 25 mm, even more preferably 47 to 59 yarns / 25 mm, and particularly preferably 49 to 57 yarns / 25 mm. If the placement density is within the above range, a glass cloth can be obtained that achieves a high level of productivity, skew characteristics, and resin impregnation. The placement densities of the warp and weft yarns may be the same or different.

[0026] [Glass Cloth Cloth Type R] The glass cloth of the present disclosure has a thickness in the range of 13 to 19 μm, a warp width and a weft width in the range of 125 to 135 μm and 200 to 240 μm, respectively (also referred to as "Cloth Type R" in the present disclosure), and the coefficient of variation of the dielectric constant of the glass cloth at 10 GHz, measured using a split cylinder resonator, is in the range of 8.0% or less.

[0027] The glass cloth (Cloth Type R) of the present disclosure, having the above-described configuration, can provide a glass cloth with excellent skew characteristics and is also excellent in productivity and resin impregnation. The reason for this is presumed, without being limited by theory, as follows: A printed wiring board has a copper foil pattern for transmitting and receiving electrical signals on the surface of a laminate composed of a matrix resin and a glass cloth. The surface of the glass cloth is discontinuous, with voids filled with the matrix resin and glass threads intermingled, and the glass cloth and matrix resin have different dielectric constants, which mainly result in differences in signal speed between the matrix resin and glass threads (commonly referred to as "skew"). Therefore, to improve skew using glass cloth, it is effective to increase the width of the glass cloth to make the surface of the glass cloth more uniform. Increasing the width of the glass cloth also improves resin impregnation. Printed wiring boards are made from prepregs obtained by impregnating glass cloth with a resin composition and then semi-curing the impregnated glass cloth. Using glass cloth with high resin impregnation properties reduces the occurrence of voids (commonly called voids) in the prepreg and printed wiring board, improving insulation reliability. Furthermore, excellent resin impregnation properties also improve the heat resistance of printed wiring boards and other components. A common method for widening the yarn width of glass cloth is to open the glass cloth. However, opening the glass cloth to widen the yarn width causes fluffing on the surface of the glass cloth, leading to reduced productivity. In other words, there is a trade-off between improving skew and resin impregnation properties and productivity (fluff quality). After extensive research, the inventors discovered that by designing the thickness, warp width, and weft width of the glass cloth within appropriate ranges, the yarn width can be sufficiently opened without applying strong opening processing to the glass cloth.Specifically, when the warp and weft widths of the glass cloth are within the ranges of 125 to 135 μm and 200 to 240 μm, respectively, a glass cloth thickness of 13 μm or more eliminates the need to excessively widen the glass cloth's width and eliminates the need for strong opening processing of the glass cloth, thereby improving the fluff quality of the glass cloth and leading to increased productivity. On the other hand, a glass cloth thickness of 19 μm or less allows the glass cloth to be sufficiently opened, improving skew and resin impregnation. Furthermore, because extremely fine patterns are formed on printed wiring boards using low-dielectric glass cloth, there is a demand for improved skew characteristics of the glass cloth. Therefore, the inventors have conducted research and found that the skew characteristics of printed wiring boards can be significantly improved by setting the thickness, warp width, and weft width of the glass cloth within the above ranges and, in addition, setting the coefficient of variation of the dielectric constant of the glass cloth at 10 GHz, measured using a split cylinder resonator, to 8.0% or less. The reason for this is that skew characteristics have traditionally been thought to be a phenomenon caused by the difference in dielectric constant between the glass cloth and the matrix resin. However, the inventors discovered that the skew characteristics are also affected by the large variation in dielectric constant within the glass cloth plane caused by the variation in elements such as boron, which are easily volatilized by heating, within the glass cloth plane during the thermal deoiling process. Therefore, the inventors conceived the idea of ​​reducing the variation in dielectric constant within the glass cloth plane to reduce the difference in skew performance not only between the glass cloth and the matrix resin but also between glass cloths themselves. As a result of extensive research, as described below, by processing the glass cloth to achieve a more uniform glass composition within the plane, the variation in dielectric constant within the glass cloth plane was reduced, leading to a significant improvement in the skew performance of printed wiring boards. As a result, a glass cloth can be obtained that achieves high productivity, skew characteristics, and resin impregnation properties.

[0028] The thickness of the glass cloth (Cloth Type R) is in the range of 13 to 19 μm, preferably in the range of 14 to 18 μm, and particularly preferably in the range of 15 to 17 μm. When the thickness of the glass cloth is in the above range, it is possible to obtain a glass cloth that achieves a higher level of productivity, skew characteristics, and resin impregnation properties.

[0029] The warp width and weft width of the glass cloth (Cloth Type R) are in the ranges of 125 to 135 μm and 200 to 240 μm, respectively, preferably 126 to 134 μm and 204 to 236 μm, respectively, more preferably 127 to 133 μm and 208 to 232 μm, respectively, and particularly preferably 128 to 132 μm and 209 to 230 μm, respectively. When the warp width and weft width of the glass cloth are within the above ranges, a glass cloth can be obtained that achieves both high productivity and excellent skew characteristics.

[0030] The standard deviations of the warp width and weft width of the glass cloth (Cloth Type R) are preferably 15 μm or less and 24 μm or less, respectively. If the standard deviation of the width is within the above range, the effect of improving the skew characteristics of the glass cloth can be easily obtained. From the viewpoint of more easily obtaining the effect of improving the skew characteristics, the standard deviations of the warp width and weft width of the glass cloth are more preferably 14 μm or less and 23 μm or less, even more preferably 13 μm or less and 22 μm or less, and particularly preferably 12 μm or less and 21 μm or less. The standard deviation of the width can be reduced, for example, by performing an opening treatment to widen the width of the glass cloth. After surface treatment with a silane coupling agent, it is preferable to perform an opening treatment using a high-pressure spray or the like. After thermal deoiling treatment, it is more preferable to simultaneously treat the glass cloth with ultrasonic waves in water to eliminate adhesion between the glass filaments. The lower limits of the standard deviations of the warp width and weft width are not limited, but may be, for example, 2 μm or more and 5 μm or more, respectively.

[0031] The glass cloth (Cloth Type R) has a coefficient of variation of the dielectric constant at 10 GHz measured using a split cylinder resonator in the range of 8.0% or less. As a result of studies conducted by the present inventors, as described below, it has been found that by controlling the amount of Na ions and Mg ions attached to the surface of the glass cloth and adjusting the conditions for thermal deoiling, it is possible to suppress the compositional variation of the glass yarns and reduce the coefficient of variation of the dielectric constant of the glass cloth to 8.0% or less. From the viewpoint of easily achieving an improvement in skew characteristics, the coefficient of variation of the dielectric constant of the glass cloth is preferably in the range of 6.0% or less, more preferably in the range of 4.0% or less, and particularly preferably in the range of 2.0% or less. The lower limit of the coefficient of variation of the dielectric constant is not limited, but may be greater than 0%, for example, 1.0% or more.

[0032] The pitch density of the warp and weft yarns constituting the glass cloth (Cloth Type R) is preferably 88 to 98 yarns / 25 mm, more preferably 89 to 97 yarns / 25 mm, even more preferably 90 to 96 yarns / 25 mm, and particularly preferably 91 to 95 yarns / 25 mm. If the pitch density is within the above range, a glass cloth can be obtained that achieves a high level of productivity, skew characteristics, and resin impregnation. The pitch densities of the warp and weft yarns may be the same or different.

[0033] [Glass Cloth Cloth Type S] The glass cloth of the present disclosure has a thickness in the range of 17 to 25 μm, a warp width and a weft width in the range of 178 to 198 μm and 310 to 342 μm, respectively (also referred to as "Cloth Type S" in the present disclosure), and the coefficient of variation of the dielectric constant of the glass cloth at 10 GHz, measured using a split cylinder resonator, is in the range of 8.0% or less.

[0034] The glass cloth (Cloth Type S) of the present disclosure, having the above-described configuration, can provide a glass cloth with excellent skew characteristics and is also excellent in productivity and resin impregnation. The reason for this is presumed, without being limited by theory, as follows: A printed wiring board has a copper foil pattern for transmitting and receiving electrical signals on the surface of a laminate composed of a matrix resin and a glass cloth. The surface of the glass cloth is discontinuous, with voids filled with the matrix resin and glass threads intermingled, and the glass cloth and matrix resin have different dielectric constants, which mainly result in differences in signal speed between the matrix resin and glass threads (commonly referred to as "skew"). Therefore, to improve skew using glass cloth, it is effective to increase the width of the glass cloth to make the surface of the glass cloth more uniform. Increasing the width of the glass cloth also improves resin impregnation. Printed wiring boards are made from prepregs obtained by impregnating glass cloth with a resin composition and then semi-curing the impregnated glass cloth. Using glass cloth with high resin impregnation properties reduces the occurrence of voids (commonly called voids) in the prepreg and printed wiring board, improving insulation reliability. Furthermore, excellent resin impregnation properties also improve the heat resistance of printed wiring boards and other components. A common method for widening the yarn width of glass cloth is to open the glass cloth. However, opening the glass cloth to widen the yarn width causes fluffing on the surface of the glass cloth, leading to reduced productivity. In other words, there is a trade-off between improving skew and resin impregnation properties and productivity (fluff quality). After extensive research, the inventors discovered that by designing the thickness, warp width, and weft width of the glass cloth within appropriate ranges, the yarn width can be sufficiently opened without applying strong opening processing to the glass cloth.Specifically, when the warp width and weft width of the glass cloth are within the ranges of 178 to 198 μm and 310 to 342 μm, respectively, a glass cloth thickness of 17 μm or more eliminates the need to excessively widen the glass cloth's thread width and the need for strong opening processing of the glass cloth, thereby improving the fluff quality of the glass cloth and leading to increased productivity. On the other hand, a glass cloth thickness of 25 μm or less allows the thread width to be sufficiently opened, improving skew and resin impregnation. Furthermore, since very fine patterns are formed on printed wiring boards using low-dielectric glass cloth, there is a demand for improved skew characteristics of the glass cloth. Therefore, the inventors have conducted research and found that the skew characteristics of printed wiring boards can be significantly improved by setting the thickness, warp width, and weft width of the glass cloth within the above ranges and, in addition, setting the coefficient of variation of the dielectric constant of the glass cloth at 10 GHz, measured using a split cylinder resonator, to 8.0% or less. The reason for this is that skew characteristics have traditionally been thought to be a phenomenon caused by the difference in dielectric constant between the glass cloth and the matrix resin. However, the inventors discovered that the skew characteristics are also affected by the large variation in dielectric constant within the glass cloth plane caused by the variation in elements such as boron, which are easily volatilized by heating, within the glass cloth plane during the thermal deoiling process. Therefore, the inventors conceived the idea of ​​reducing the variation in dielectric constant within the glass cloth plane to reduce the difference in skew performance not only between the glass cloth and the matrix resin but also between glass cloths themselves. As a result of extensive research, as described below, by processing the glass cloth to achieve a more uniform glass composition within the plane, the variation in dielectric constant within the glass cloth plane was reduced, leading to a significant improvement in the skew performance of printed wiring boards. As a result, a glass cloth can be obtained that achieves high productivity, skew characteristics, and resin impregnation properties.

[0035] The thickness of the glass cloth (cloth type S) is in the range of 17 to 25 μm, preferably in the range of 18 to 24 μm, more preferably in the range of 19 to 23 μm, and particularly preferably in the range of 20 to 22 μm. When the thickness of the glass cloth is in the above range, it is possible to obtain a glass cloth that achieves a higher level of productivity, skew characteristics, and resin impregnation properties.

[0036] The warp width and weft width of the glass cloth (cloth type S) are in the ranges of 178 to 198 μm and 310 to 342 μm, respectively, preferably in the ranges of 180 to 196 μm and 313 to 339 μm, respectively, more preferably in the ranges of 182 to 194 μm and 316 to 336 μm, respectively, and particularly preferably in the ranges of 184 to 192 μm and 320 to 333 μm, respectively. When the warp width and weft width of the glass cloth are within the above ranges, a glass cloth can be obtained that achieves both high productivity and high skew characteristics.

[0037] The standard deviations of the warp width and weft width of the glass cloth (Cloth Type S) are preferably 20 μm or less and 40 μm or less, respectively. If the standard deviation of the width is within the above range, the effect of improving the skew characteristics of the glass cloth can be easily obtained. From the viewpoint of more easily obtaining the effect of improving the skew characteristics, the standard deviations of the warp width and weft width of the glass cloth are more preferably 19 μm or less and 39 μm or less, even more preferably 18 μm or less and 38 μm or less, and particularly preferably 17 μm or less and 37 μm or less. The standard deviation of the width can be reduced, for example, by performing a fiber-opening treatment to widen the width of the glass cloth. After surface treatment with a silane coupling agent, it is preferable to perform a fiber-opening treatment using a high-pressure spray or the like. After thermal deoiling treatment, it is more preferable to simultaneously treat the glass cloth with ultrasonic waves in water to eliminate adhesion between the glass filaments. The lower limits of the standard deviations of the warp width and weft width are not limited, but may be, for example, 5 μm or more and 10 μm or more, respectively.

[0038] The glass cloth (Cloth Type S) has a coefficient of variation of the dielectric constant at 10 GHz measured using a split cylinder resonator in the range of 8.0% or less. As a result of studies conducted by the present inventors, as described below, it has been found that by controlling the amount of Na ions and Mg ions attached to the surface of the glass cloth and adjusting the conditions for thermal deoiling, it is possible to suppress the compositional variation of the glass yarns and reduce the coefficient of variation of the dielectric constant of the glass cloth to 8.0% or less. From the viewpoint of easily achieving an improvement in skew characteristics, the coefficient of variation of the dielectric constant of the glass cloth is preferably in the range of 6.0% or less, more preferably in the range of 4.0% or less, and particularly preferably in the range of 2.0% or less. The lower limit of the coefficient of variation of the dielectric constant is not limited, but may be greater than 0%, for example, 1.0% or more.

[0039] The placement density of the warp and weft yarns constituting the glass cloth (cloth type S) is preferably 65 to 80 yarns / 25 mm, more preferably 67 to 79 yarns / 25 mm, even more preferably 68 to 78 yarns / 25 mm, and particularly preferably 69 to 77 yarns / 25 mm. If the placement density is within the above range, a glass cloth can be obtained that achieves a high level of productivity, skew characteristics, and resin impregnation. The placement densities of the warp and weft yarns may be the same or different.

[0040] [Glass Cloth Cloth Type T] The glass cloth of the present disclosure has a thickness in the range of 20 to 25 μm, a warp width and a weft width in the range of 176 to 232 μm and 239 to 353 μm, respectively (also referred to as "Cloth Type T" in the present disclosure), and the coefficient of variation of the dielectric constant of the glass cloth at 10 GHz, measured using a split cylinder resonator, is in the range of 8.0% or less.

[0041] The glass cloth (Cloth Type T) of the present disclosure, having the above-described configuration, can provide a glass cloth with excellent skew characteristics and is also excellent in productivity and resin impregnation. The reason for this is presumed, without being limited by theory, as follows: A printed wiring board has a copper foil pattern for transmitting and receiving electrical signals on the surface of a laminate composed of a matrix resin and a glass cloth. The surface of the glass cloth is discontinuous, with voids filled with the matrix resin and glass threads intermingled, and the glass cloth and matrix resin have different dielectric constants, which mainly result in differences in signal speed between the matrix resin and the glass threads (commonly referred to as "skew"). Therefore, to improve skew using glass cloth, it is effective to increase the width of the glass cloth to make the surface of the glass cloth more uniform. Increasing the width of the glass cloth also improves resin impregnation. Printed wiring boards are made from prepregs obtained by impregnating glass cloth with a resin composition and then semi-curing the impregnated glass cloth. Using glass cloth with high resin impregnation properties reduces the occurrence of voids (commonly called voids) in the prepreg and printed wiring board, improving insulation reliability. Furthermore, excellent resin impregnation properties also improve the heat resistance of printed wiring boards and other components. A common method for widening the yarn width of glass cloth is to open the glass cloth. However, opening the glass cloth to widen the yarn width causes fluffing on the surface of the glass cloth, leading to reduced productivity. In other words, there is a trade-off between improving skew and resin impregnation properties and productivity (fluff quality). After extensive research, the inventors discovered that by designing the thickness, warp width, and weft width of the glass cloth within appropriate ranges, the yarn width can be sufficiently opened without applying strong opening processing to the glass cloth.Specifically, when the warp width and weft width of the glass cloth are within the ranges of 176 to 232 μm and 329 to 353 μm, respectively, a thickness of 20 μm or more eliminates the need to excessively widen the glass cloth's thread width and the need for strong opening processing of the glass cloth, thereby improving the fluff quality of the glass cloth and leading to increased productivity. On the other hand, a thickness of 30 μm or less ensures sufficient opening of the thread width, improving skew and resin impregnation. Furthermore, since very fine patterns are formed on printed wiring boards using low-dielectric glass cloth, there is a demand for improved skew characteristics of the glass cloth. Therefore, the inventors have conducted studies and found that the skew characteristics of printed wiring boards can be significantly improved by setting the thickness, warp width, and weft width of the glass cloth within the above ranges and, in addition, setting the coefficient of variation of the dielectric constant of the glass cloth at 10 GHz, measured using a split cylinder resonator, to 8.0% or less. The reason for this is that skew characteristics have traditionally been thought to be a phenomenon caused by the difference in dielectric constant between the glass cloth and the matrix resin. However, the inventors discovered that the skew characteristics are also affected by the large variation in dielectric constant within the glass cloth plane caused by the variation in elements such as boron, which are easily volatilized by heating, within the glass cloth plane during the thermal deoiling process. Therefore, the inventors conceived the idea of ​​reducing the variation in dielectric constant within the glass cloth plane to reduce the difference in skew performance not only between the glass cloth and the matrix resin but also between glass cloths themselves. As a result of extensive research, as described below, by processing the glass cloth to achieve a more uniform glass composition within the plane, the variation in dielectric constant within the glass cloth plane was reduced, leading to a significant improvement in the skew performance of printed wiring boards. As a result, a glass cloth can be obtained that achieves high productivity, skew characteristics, and resin impregnation properties.

[0042] The thickness of the glass cloth (cloth type T) is in the range of 20 to 30 μm, preferably in the range of 21 to 29 μm, more preferably in the range of 22 to 28 μm, even more preferably in the range of 23 to 27 μm, and particularly preferably in the range of 24 to 26 μm. When the thickness of the glass cloth is in the above range, it is possible to obtain a glass cloth that achieves a high degree of compatibility between productivity, skew characteristics, and resin impregnation properties.

[0043] The warp width and weft width of the glass cloth (cloth type T) are in the ranges of 176 to 232 μm and 329 to 353 μm, respectively, preferably 183 to 225 μm and 332 to 350 μm, respectively, more preferably 190 to 218 μm and 335 to 347 μm, respectively, and particularly preferably 197 to 211 μm and 338 to 344 μm, respectively. When the warp width and weft width of the glass cloth are within the above ranges, a glass cloth can be obtained that achieves both high productivity and high skew characteristics.

[0044] The standard deviations of the warp width and weft width of the glass cloth (Cloth Type T) are preferably 20 μm or less and 43 μm or less, respectively. If the standard deviation of the width is within the above range, the effect of improving the skew characteristics of the glass cloth can be easily obtained. From the viewpoint of more easily obtaining the effect of improving the skew characteristics, the standard deviations of the warp width and weft width of the glass cloth are more preferably 19 μm or less and 42 μm or less, even more preferably 18 μm or less and 41 μm or less, and particularly preferably 17 μm or less and 40 μm or less. The standard deviation of the width can be reduced, for example, by performing an opening treatment to widen the width of the glass cloth. After surface treatment with a silane coupling agent, it is preferable to perform an opening treatment using a high-pressure spray or the like. After thermal deoiling treatment, it is more preferable to simultaneously treat the glass cloth with ultrasonic waves in water to eliminate adhesion between the glass filaments. The lower limits of the standard deviations of the warp width and weft width are not limited, but may be, for example, 5 μm or more and 10 μm or more, respectively.

[0045] The glass cloth (Cloth Type T) has a coefficient of variation of the dielectric constant at 10 GHz measured using a split cylinder resonator in the range of 8.0% or less. As a result of studies conducted by the present inventors, as described below, it has been found that by controlling the amount of Na ions and Mg ions attached to the surface of the glass cloth and adjusting the conditions for thermal deoiling, it is possible to suppress the compositional variation of the glass yarns and reduce the coefficient of variation of the dielectric constant of the glass cloth to 8.0% or less. From the viewpoint of easily achieving an improvement in skew characteristics, the coefficient of variation of the dielectric constant of the glass cloth is preferably in the range of 6.0% or less, more preferably in the range of 4.0% or less, and particularly preferably in the range of 2.0% or less. The lower limit of the coefficient of variation of the dielectric constant is not limited, but may be greater than 0%, for example, 1.0% or more.

[0046] The placement density of the warp and weft yarns constituting the glass cloth (cloth type T) is preferably 60 to 80 yarns / 25 mm, more preferably 61 to 79 yarns / 25 mm, even more preferably 62 to 78 yarns / 25 mm, and particularly preferably 63 to 77 yarns / 25 mm. If the placement density is within the above range, a glass cloth can be obtained that achieves a high level of productivity, skew characteristics, and resin impregnation. The placement densities of the warp and weft yarns may be the same or different.

[0047] [Glass thread] The average filament diameter of the glass filaments constituting the glass yarn is preferably 2.5 to 9.0 μm, more preferably 2.5 to 7.5 μm, even more preferably 3.5 to 7.0 μm, still more preferably 3.5 to 6.5 μm, and particularly preferably 3.5 to 6.0 μm. When the filament diameter is within the above range, the filaments have a high breaking strength, and therefore the resulting glass cloth is less likely to produce fluff.

[0048] The coefficient of variation of the filament diameter is preferably 10.0% or less, more preferably 7.0% or less, even more preferably 5.0% or less, even more preferably 4.0% or less, and particularly preferably 0.03% or less. When the coefficient of variation of the filament diameter of the glass fiber is 10.0% or less, the variation in the TEX of the glass yarn is reduced, thereby suppressing the variation in the dielectric constant of the glass cloth. As a result, the skew characteristics of the printed wiring board are improved. The coefficient of variation of the TEX of the glass yarn is preferably 4.0% or less, more preferably 3.0% or less. When the coefficient of variation of the TEX of the glass yarn is 4.0% or less, the variation in the dielectric constant of the glass cloth can be effectively suppressed, and as a result, the skew characteristics of the printed wiring board can be further improved. The coefficient of variation of the TEX of the glass yarn can be reduced by increasing the frequency of replacing the nozzle (bushing) when spinning the glass yarn. The lower limit of the coefficient of variation of the TEX is not limited, but may be greater than 0%, for example, 1.0% or more.

[0049] [Glass Type A] One of the compositions of the glass yarn (glass type A) preferably contains, based on the total mass of the glass yarn, 45 to 55 mass% SiO2, 17 to 27 mass% B2O3, 11 to 21 mass% Al2O3, a total of 2.7 to 5.7 mass% CaO and MgO, and a total of 0 to 0.15 mass% Li2O, K2O, and Na2O, calculated as oxides. Having a glass composition within the above ranges facilitates the provision of glass cloth exhibiting low dielectric constants and dielectric loss tangents. From the viewpoint of facilitating the production of glass cloth with even lower dielectric loss tangents, the SiO2 content is more preferably in the range of 46 to 54 mass%, even more preferably in the range of 47 to 53 mass%, and particularly preferably in the range of 48 to 52 mass%. The B2O3 content is more preferably in the range of 18 to 26 mass%, even more preferably in the range of 19 to 25 mass%, and particularly preferably in the range of 20 to 24 mass%. The content of Al2O3 is more preferably in the range of 12 to 20 mass%, even more preferably in the range of 13 to 19 mass%, and particularly preferably in the range of 14 to 18 mass%. The total content of CaO and MgO is more preferably in the range of 3.0 to 5.4 mass%, even more preferably in the range of 3.3 to 5.1 mass%, and particularly preferably in the range of 3.6 to 4.8 mass%. Alternatively, the total content of CaO and MgO may be in the range of 1.5 to 4.5 mass%, 2.0 to 4.0 mass%, 2.5 to 3.5 mass%, or 2.7 to 3.3 mass%. The total content of Li2O, KO, and Na2O is more preferably in the range of 0.01 to 0.13 mass%, even more preferably in the range of 0.02 to 0.11 mass%, and particularly preferably in the range of 0.03 to 0.09 mass%. The above contents can be measured by ICP atomic emission spectroscopy as described in the Examples.

[0050] From the viewpoint of improving the productivity of the glass yarn (glass type A), the glass yarn preferably contains, based on the total mass of the glass yarn, TiO2 in the range of 0.15 to 0.45 mass% in terms of oxides, P2O5 in the range of 2.5 to 7.5 mass%, and SrO in the range of 0 to 0.02 mass%. From the viewpoint of easily achieving better productivity, the TiO2 content is more preferably in the range of 0.17 to 0.43 mass%, even more preferably in the range of 0.20 to 40 mass%, and particularly preferably in the range of 0.25 to 0.35 mass%. The P2O5 content is more preferably in the range of 3.0 to 7.0 mass%, even more preferably in the range of 3.5 to 6.5 mass%, and particularly preferably in the range of 4.0 to 6.0 mass%. The SrO content is more preferably in the range of 0.0005 to 0.015 mass%, even more preferably in the range of 0.001 to 0.010 mass%, and particularly preferably in the range of 0.0015 to 0.005 mass%. The above contents can be measured by ICP atomic emission spectrometry as described in the Examples.

[0051] [Glass Type B] One of the glass fiber compositions (glass type B) preferably contains, based on the total mass of the glass fiber, 48 to 58 mass% SiO2, 18 to 28 mass% B2O3, 8 to 18 mass% Al2O3, a total of 3.4 to 6.4 mass% CaO and MgO, and a total of 0 to 0.15 mass% Li2O, K2O, and Na2O, calculated as oxides. Having a glass composition within the above ranges facilitates the provision of glass cloth exhibiting low dielectric constants and dielectric loss tangents. From the viewpoint of facilitating the production of glass cloth with even lower dielectric loss tangents, the SiO2 content is more preferably in the range of 49 to 57 mass%, even more preferably in the range of 50 to 56 mass%, and particularly preferably in the range of 51 to 55 mass%. The B2O3 content is more preferably in the range of 19 to 27 mass%, even more preferably in the range of 20 to 26 mass%, and particularly preferably in the range of 21 to 25 mass%. The content of Al2O3 is more preferably in the range of 9 to 17 mass%, even more preferably in the range of 10 to 16 mass%, and particularly preferably in the range of 11 to 15 mass%. The total content of CaO and MgO is more preferably in the range of 3.6 to 6.2 mass%, even more preferably in the range of 3.8 to 6.0 mass%, and particularly preferably in the range of 4.0 to 5.8 mass%. The total content of Li2O, KO, and Na2O is more preferably in the range of 0.01 to 0.13 mass%, even more preferably in the range of 0.03 to 0.11 mass%, and particularly preferably in the range of 0.05 to 0.09 mass%. The above contents can be measured by ICP atomic emission spectroscopy as described in the Examples.

[0052] From the viewpoint of improving the desmear resistance (resistance of glass to dissolution in a desmear solution) of the glass yarn (glass type B), the glass yarn preferably contains, in oxide equivalents, 0.9 to 2.9 mass% of TiO2, 0 to 0.03 mass% of P2O5, and 0 to 3 mass% of SrO, based on the total mass of the glass yarn. From the viewpoint of easily achieving better productivity, the content of TiO2 is more preferably in the range of 1.1 to 2.7 mass%, even more preferably in the range of 1.3 to 2.5 mass%, and particularly preferably in the range of 1.5 to 2.3 mass%. The content of P2O5 is more preferably in the range of 0.001 to 0.025 mass%, even more preferably in the range of 0.002 to 0.023 mass%, and particularly preferably in the range of 0.003 to 0.020 mass%. The SrO content is more preferably in the range of 0.2 to 2.5 mass%, even more preferably in the range of 0.2 to 2.0 mass%, and particularly preferably in the range of 0.4 to 1.5 mass%. The above contents can be measured by ICP atomic emission spectrometry as described in the Examples.

[0053] [Glass Type C] One glass fiber composition (glass type C) preferably contains, based on the total mass of the glass fiber, 48 to 58 mass% SiO2, 17 to 27 mass% B2O3, 11 to 21 mass% Al2O3, a total of 3.5 to 6.5 mass% CaO and MgO, and a total of 0 to 0.1 mass% Li2O, K2O, and Na2O, calculated as oxides. Having a glass composition within the above ranges facilitates the production of glass cloth exhibiting low dielectric constants and dielectric loss tangents. From the viewpoint of facilitating the production of glass cloth with even lower dielectric loss tangents, the SiO2 content is more preferably in the range of 49 to 57 mass%, even more preferably in the range of 50 to 56 mass%, and particularly preferably in the range of 51 to 55 mass%. The B2O3 content is more preferably in the range of 18 to 26 mass%, even more preferably in the range of 19 to 25 mass%, and particularly preferably in the range of 20 to 24 mass%. The content of Al2O3 is more preferably in the range of 12 to 20 mass%, even more preferably in the range of 13 to 19 mass%, and particularly preferably in the range of 14 to 18 mass%. The total content of CaO and MgO is more preferably in the range of 3.7 to 6.3 mass%, even more preferably in the range of 4.0 to 6.0 mass%, and particularly preferably in the range of 4.5 to 5.5 mass%. The total content of Li2O, KO, and Na2O is more preferably in the range of 0.005 to 0.09 mass%, even more preferably in the range of 0.01 to 0.08 mass%, and particularly preferably in the range of 0.02 to 0.07 mass%. The above contents can be measured by ICP atomic emission spectroscopy as described in the Examples.

[0054] From the viewpoint of improving the productivity of the glass yarn (glass type C), the glass yarn preferably contains, in oxide equivalents, 0 to 0.3 mass% of TiO2, 0 to 4.2 mass% of P2O5, and 0 to 1 mass% of SrO, based on the total mass of the glass yarn. From the viewpoint of easily achieving better productivity, the TiO2 content is more preferably 0.005 to 0.25 mass%, even more preferably 0.01 to 0.20 mass%, and particularly preferably 0.013 to 0.15 mass%. The P2O5 content is more preferably 1.0 to 4.0 mass%, even more preferably 1.3 to 3.7 mass%, and particularly preferably 1.6 to 3.4 mass%. The SrO content is more preferably 0.05 to 0.9 mass%, even more preferably 0.1 to 0.8 mass%, and particularly preferably 0.14 to 0.7 mass%. The above contents can be measured by ICP emission spectroscopy as described in the Examples.

[0055] [Glass Type D] One of the glass yarn compositions (glass type D) preferably contains, based on the total mass of the glass yarn, 47 to 57 mass% SiO2, 22 to 32 mass% B2O3, 8 to 18 mass% Al2O3, a total of 1.4 to 4.4 mass% CaO and MgO, and a total of 0.1 to 1.0 mass% Li2O, K2O, and Na2O, calculated as oxides. Having a glass composition within the above ranges facilitates the provision of glass cloth exhibiting low dielectric constants and dielectric loss tangents. From the viewpoint of facilitating the production of glass cloth with even lower dielectric loss tangents, the SiO2 content is more preferably in the range of 48 to 56 mass%, even more preferably in the range of 49 to 55 mass%, and particularly preferably in the range of 50 to 54 mass%. The B2O3 content is more preferably in the range of 23 to 31 mass%, even more preferably in the range of 24 to 30 mass%, and particularly preferably in the range of 25 to 29 mass%. The content of Al2O3 is more preferably in the range of 9 to 17 mass%, even more preferably in the range of 10 to 16 mass%, and particularly preferably in the range of 11 to 15 mass%. The total content of CaO and MgO is more preferably in the range of 1.6 to 4.2 mass%, even more preferably in the range of 1.8 to 4.0 mass%, and particularly preferably in the range of 2.0 to 3.8 mass%. The total content of Li2O, K2O, and Na2O is more preferably in the range of 0.12 to 0.9 mass%, even more preferably in the range of 0.14 to 0.7 mass%, and particularly preferably in the range of 0.16 to 0.5 mass%. Alternatively, the total content of Li2O, K2O, and Na2O may be in the range of 0.1 to 0.5 mass%, 0.12 to 0.48 mass%, 0.14 to 0.46 mass%, or 0.16 to 0.44 mass%. The above contents can be measured by ICP atomic emission spectroscopy as described in the Examples.

[0056] From the viewpoint of preventing bubbles from being trapped inside the glass filament (glass type D), the glass filament preferably contains, in oxide equivalents, 0 to 1 mass% of TiO2, 0 to 0.2 mass% of P2O5, and 0 to 0.3 mass% of SrO, based on the total mass of the glass filament. From the viewpoint of facilitating the production of glass filaments with less bubbles and greater uniformity, the content of TiO2 is more preferably in the range of 0.1 to 0.9 mass%, even more preferably in the range of 0.2 to 0.8 mass%, and particularly preferably in the range of 0.3 to 0.7 mass%. The content of P2O5 is more preferably in the range of 0.003 to 0.18 mass%, even more preferably in the range of 0.006 to 0.16 mass%, and particularly preferably in the range of 0.008 to 0.14 mass%. The SrO content is more preferably in the range of 0.001 to 0.25 mass%, even more preferably in the range of 0.01 to 0.20 mass%, and particularly preferably in the range of 0.02 to 0.15 mass%. The above contents can be measured by ICP atomic emission spectroscopy as described in the Examples.

[0057] [Glass Type E] One of the compositions of the glass yarn according to this embodiment (glass type E) preferably contains, based on the total mass of the glass yarn, 47 to 57 mass% SiO2, 18 to 28 mass% B2O3, 9 to 19 mass% Al2O3, a total of 3.4 to 6.4 mass% CaO and MgO, and a total of 0 to 0.3 mass% Li2O, K2O, and Na2O, calculated as oxides. Having a glass composition within the above ranges facilitates the provision of glass cloth exhibiting low dielectric constants and dielectric loss tangents. From the viewpoint of facilitating the production of glass cloth with even lower dielectric loss tangents, the SiO2 content is more preferably in the range of 48 to 56 mass%, even more preferably in the range of 49 to 55 mass%, and particularly preferably in the range of 50 to 54 mass%. The B2O3 content is more preferably in the range of 19 to 27 mass%, even more preferably in the range of 20 to 26 mass%, and particularly preferably in the range of 21 to 25 mass%. Alternatively, B2O3 may be in the range of 19-29 mass%, 20-28 mass%, 21-27 mass%, or 22-26 mass%. Al2O3 is more preferably in the range of 10-18 mass%, even more preferably in the range of 11-17 mass%, and particularly preferably in the range of 12-16 mass%. Alternatively, Al2O3 may be in the range of 7-17 mass%, 8-16 mass%, 9-16 mass%, or 10-15 mass%. The total content of CaO and MgO is more preferably in the range of 3.6-6.2 mass%, even more preferably in the range of 3.8-6.0 mass%, and particularly preferably in the range of 4.1-5.7 mass%. The total content of Li2O, K2O, and Na2O is more preferably in the range of 0.01-0.25 mass%, even more preferably in the range of 0.02-0.20 mass%, and particularly preferably in the range of 0.03-0.15 mass%. The above contents can be measured by ICP emission spectroscopy as described in the Examples.

[0058] From the viewpoint of preventing air bubbles from being trapped inside the glass yarn (glass type E) and improving the fluff quality of the glass yarn, the glass yarn preferably contains, in oxide equivalents, 0.01 to 0.3 mass% of TiO2, 0 to 0.2 mass% of P2O5, and 0 to 0.3 mass% of SrO, based on the total mass of the glass yarn. From the viewpoint of facilitating the production of more uniform glass yarns free of air bubbles and of facilitating the control of fluff quality, the content of TiO2 is more preferably in the range of 0.02 to 0.25 mass%, even more preferably in the range of 0.03 to 0.2 mass%, and particularly preferably in the range of 0.04 to 0.15 mass%. The content of P2O5 is more preferably in the range of 0.001 to 0.15 mass%, even more preferably in the range of 0.0015 to 0.12 mass%, and particularly preferably in the range of 0.002 to 0.08 mass%. The SrO content is more preferably in the range of 0.0001 to 0.25 mass%, even more preferably in the range of 0.0005 to 0.20 mass%, and particularly preferably in the range of 0.001 to 0.10 mass%. The above contents can be measured by ICP atomic emission spectroscopy as described in the Examples.

[0059] [Glass Type F] One of the compositions of the glass yarn according to this embodiment (glass type F) preferably contains, in oxide equivalents, 47 to 57 mass% SiO, 20 to 30 mass% BO, 8 to 18 mass% AlO, a total of 3.0 to 7.0 mass% CaO and MgO, and a total of 0 to 0.3 mass% LiO, KO, and NaO, based on the total mass of the glass yarn. Having a glass composition within the above ranges facilitates the provision of glass cloth exhibiting low dielectric constants and dielectric loss tangents. From the viewpoint of facilitating the production of glass cloth with even lower dielectric loss tangents, the SiO content is more preferably in the range of 48 to 56 mass%, even more preferably in the range of 49 to 55 mass%, and particularly preferably in the range of 50 to 54 mass%. The BO content is more preferably in the range of 21 to 29 mass%, even more preferably in the range of 22 to 28 mass%, and particularly preferably in the range of 23 to 27 mass%. The content of Al2O3 is more preferably in the range of 9 to 17 mass%, even more preferably in the range of 10 to 16 mass%, and particularly preferably in the range of 11 to 15 mass%. The total content of CaO and MgO is more preferably in the range of 3.2 to 6.8 mass%, even more preferably in the range of 3.4 to 6.6 mass%, and particularly preferably in the range of 3.6 to 6.4 mass%. The total content of Li2O, KO, and Na2O is more preferably in the range of 0.001 to 0.25 mass%, even more preferably in the range of 0.002 to 0.2 mass%, and particularly preferably in the range of 0.003 to 0.1 mass%. The above contents can be measured by ICP atomic emission spectroscopy as described in the Examples.

[0060] From the viewpoint of good spinning stability due to the prevention of air bubbles from entering the glass fiber (glass type E) and the uniform melting of the glass, the glass fiber preferably contains, in oxide equivalents, 1.0 to 5.0 mass% of TiO2, 0 to 0.1 mass% of P2O5, and 0 to 0.2 mass% of SrO, based on the total mass of the glass fiber. From the viewpoint of facilitating the production of glass fibers that are less prone to air bubbles and have excellent spinning stability, the content of TiO2 is more preferably in the range of 1.2 to 4.8 mass%, even more preferably in the range of 1.5 to 4.5 mass%, and particularly preferably in the range of 1.8 to 4.2 mass%. The content of P2O5 is more preferably in the range of 0 to 0.08 mass%, even more preferably in the range of 0 to 0.05 mass%, and particularly preferably in the range of 0 to 0.03 mass%. The SrO content is more preferably in the range of 0 to 0.01 mass%, even more preferably in the range of 0 to 0.005 mass%, and particularly preferably in the range of 0 to 0.001 mass%. The above contents can be measured by ICP atomic emission spectroscopy as described in the Examples.

[0061] [Na ion amount and Mg ion amount] The amounts of Na ions and Mg ions adhering to the surface of the glass cloth before thermal deoiling are preferably in the range of 0 to 50 ppm and 0 to 30 ppm, respectively. The inventors' studies have revealed that when glass cloth is subjected to thermal deoiling at high temperatures of 300 to 400°C, the Na ions and Mg ions adhering to the glass surface are absorbed into the glass. The absorption of Na ions and Mg ions into the glass alters the original glass composition, resulting in changes in the dielectric constant and dielectric loss tangent of the glass. Therefore, by controlling the amounts of Na ions and Mg ions adhering to the surface of the glass cloth before thermal deoiling within a certain range, the occurrence of a difference in dielectric constant between the longitudinal and transverse directions of the glass cloth can be suppressed, resulting in a glass cloth with excellent skew characteristics. From the viewpoint of easily achieving an improvement in skew characteristics, the amount of Na ions adhering to the surface of the glass cloth is preferably 40 ppm or less, more preferably 30 ppm or less, even more preferably 20 ppm or less, and particularly preferably 10 ppm or less. The amount of Mg ions attached to the surface of the glass cloth is preferably 25 ppm or less, more preferably 20 ppm or less, even more preferably 15 ppm or less, and particularly preferably 10 ppm or less.

[0062] The amounts of Na ions and Mg ions attached to the surface of the glass cloth can be controlled by the manufacturing method of the glass cloth described later. Specifically, they can be controlled by washing the glass cloth, the ion content of the solvent used for washing, and the amount of sizing agent attached. The amounts of Na ions and Mg ions are measured by the method described in the Examples.

[0063] [Sizing agent] The glass cloth before thermal deoiling may be surface-treated with a sizing agent. That is, the glass yarn may be surface-treated with a sizing agent. From the viewpoints of improving the convergence of the glass yarn, reducing fuzz, improving weaving properties, etc., the sizing agent preferably contains at least one selected from the group consisting of starch, PVA resin, polyurethane resin, epoxy resin, and acrylic resin as a main component. From the viewpoint of suppressing fuzz in the glass cloth, the sizing agent more preferably contains starch and / or PVA resin as a main component. Here, "main component" means the component that accounts for the largest mass % in the sizing agent, for example, a component that accounts for 50 mass % or more, 65 mass % or more, 80 mass % or more, or 95 mass % or more.

[0064] <Glass cloth manufacturing method> The method for producing a glass cloth according to the present disclosure includes a step of weaving glass yarns consisting of a plurality of glass filaments as warps and wefts to obtain a glass cloth (weaving step). The method preferably includes an inspection step (TEX inspection step) before the weaving step, in which all the glass yarns used are inspected to determine whether the coefficient of variation of TEX is 4.0% or less. The method preferably further includes, before, during, or after the weaving step, a step of opening the glass yarns before thermal deoiling (opening step before thermal deoiling), a step of cleaning the glass yarns before thermal deoiling with a solvent (cleaning step before thermal deoiling), and a step of thermally deoiling the glass yarns thereafter (thermal deoiling step). This suppresses not only the influence of TEX fluctuations in the glass cloth but also fluctuations in the glass composition caused by the thermal deoiling step, thereby suppressing variations in the dielectric tangent of the glass cloth. The method for producing a glass cloth according to the present disclosure may further include a step of cleaning and opening the washed and thermally deoiled glass yarns while transporting them in a liquid irradiated with ultrasonic waves at a speed of 50 m / min or less (cleaning and opening step). This makes it easier to adjust the warp width and weft width of the glass cloth and their standard deviations to fall within the above-mentioned preferred ranges, thereby making it possible to provide a glass cloth that has excellent resin impregnation properties and can improve the heat resistance of printed wiring boards and the like.

[0065] The above-mentioned glass treatment methods (opening step before thermal deoiling, cleaning step before thermal deoiling, thermal deoiling step, and cleaning and opening step) can be applied to glass yarns before weaving, and can also be applied to woven glass cloth. In other words, the step of weaving glass yarns to obtain glass cloth may be performed before, during, or after the glass treatment method. The method may further include a surface treatment step and a post-surface treatment opening step after the thermal deoiling step. Hereinafter, an embodiment including a TEX inspection step, a pre-heat deoiling opening step, a pre-heat deoiling cleaning step, a thermal deoiling step, a cleaning and opening step, a surface treatment step, and a post-surface treatment opening step in this order will be described as an example. However, the glass cloth manufacturing method of the present disclosure is not limited to this.

[0066] [Glass yarn TEX inspection process] The TEX of all glass yarns used in the glass cloth of the present disclosure is preferably measured, and only glass yarns with a coefficient of variation of 4.0% or less are used. The TEX of the glass yarns is measured according to the method described in JIS 3420 7.1. If the variation in the TEX value of the glass yarns is small, the variation in the dielectric constant and dielectric loss tangent within the plane of the printed wiring board can be further reduced, thereby further improving the skew characteristics.

[0067] [Opening process before heat deoiling] The glass cloth of the present disclosure is preferably subjected to an opening treatment before thermal deoiling. By performing an opening treatment on the glass cloth before thermal deoiling, it is possible to efficiently widen the yarn width while preventing fuzz from occurring on the surface of the glass cloth. The opening method is not particularly limited, and examples include opening methods using spray water (high-pressure water opening), a vibro washer, ultrasonic water, a mangle, etc. From the viewpoint of performing an opening treatment and facilitating the washing off of the sizing agent adhering to the surface of the glass yarns with water, opening methods using spray water (high-pressure water opening) and a vibro washer are preferred.

[0068] [Cleaning process before thermal deoiling] The pre-thermal deoiling washing step includes a step of reducing the amount of sizing agent by washing the glass cloth before thermal deoiling with a solvent. This reduces adhesion of the sizing agent to the glass filaments and the sizing agent combustion residue during thermal deoiling, thereby improving the resin impregnation of the resulting glass cloth. From the viewpoint of washing efficiency, water is preferably used as the solvent for washing in this process, and the temperature is preferably 50°C or higher. Using water at 50°C or higher allows excess sizing agent to be washed away while leaving behind an amount of sizing agent necessary to protect the glass filaments until the thermal deoiling step. The water temperature is preferably 50°C or higher but lower than 100°C. The lower limit of the water temperature is more preferably 55°C or higher, even more preferably 60°C or higher, and even more preferably 65°C or higher. The upper limit of the water temperature that can be combined with these lower limits is more preferably 95°C or lower, even more preferably 90°C or lower. The method for washing the glass cloth greige is not particularly limited, but possible methods include, for example, ultrasonic methods (e.g., ultrasonic vibrators), spraying (e.g., high-pressure spraying), and steam spraying. From the viewpoint of low-cost processing, a preferred method is to immerse the glass cloth greige in a tank containing a cleaning solution, remove excess cleaning solution with a squeeze roller or the like, and then dry the glass cloth greige. In this case, the immersion time may be, for example, 2 seconds or more, 5 seconds or more, 10 seconds or more, or 15 seconds or more, and 120 seconds or less, 90 seconds or less, 60 seconds or less, or 45 seconds or less.

[0069] In order to easily control the coefficient of variation of the dielectric constant of the glass cloth to 8.0% or less, it is preferable to use cleaning water with few impurities, such as RO water, ion-exchanged water, or distilled water, for the cleaning water used in the pre-heat deoiling cleaning step. Specifically, the amount of Na ions in the cleaning water is preferably 20 ppm or less, more preferably 15 ppm or less, even more preferably 12 ppm or less, even more preferably 10 ppm or less, particularly preferably 7 ppm or less, and most preferably 1.5 ppm or less. If the amount of Na ions in the cleaning solution is 20 ppm or less, the amount of Na ions adhering to the glass cloth surface is easily reduced. Furthermore, the amount of Mg ions is preferably 18 ppm or less, more preferably 12 ppm or less, even more preferably 8 ppm or less, even more preferably 6 ppm or less, particularly preferably 3 ppm or less, and most preferably 1 ppm or less. If the amount of Mg ions in the cleaning solution is 18 ppm or less, the amount of Mg ions adhering to the glass cloth surface is easily reduced. The inventors have found that by reducing the amounts of Na ions and Mg ions, it is possible to suppress the ion exchange reaction between Na ions and Mg ions attached to the surface of the glass fibers and the glass composition when the glass cloth is subjected to a thermal deoiling treatment, and as a result, the variations in the dielectric constant and dielectric loss tangent of the glass cloth are further reduced. Therefore, by washing the glass cloth with washing water containing Na ions and Mg ions in the above ranges, it is possible to further improve the skew characteristics.

[0070] [Heat deoiling process] In the thermal deoiling process, any known heating method, heating medium, heating mechanism, heating device, or heating component can be used as long as it can suitably control the thermal deoiling temperature. However, from the viewpoint of productivity, it is generally known to treat a plurality of glass cloths wrapped around a metal core tube in a batch oven (batch oven method). In this batch oven method, the surface layer of the glass cloth roll is easily heated, while the inner layer is difficult to heat, resulting in different thermal histories between the surface and inner layers. In this regard, the present inventors focused on suppressing the variation in the dielectric constant within the glass cloth plane by reducing the difference in thermal history between the surface and inner layers, which has not been considered important in the past. After extensive research, the present inventors found that performing the thermal deoiling process multiple times is effective in making the difference in thermal history of the glass cloth roll as uniform as possible. Specifically, by rewinding the glass cloth that has been subjected to thermal deoiling treatment onto another metal core tube, the inner layer side and the surface layer side of the glass cloth are reversed, and then the same thermal deoiling treatment is performed again, thereby making it possible to perform a thermal deoiling treatment with a uniform thermal history in the width direction and longitudinal direction of the glass cloth.

[0071] In order to reduce the variation in the dielectric constant of the glass cloth, the temperature for the thermal deoiling treatment is preferably 330 to 450°C, more preferably 340 to 440°C, even more preferably 350 to 430°C, and particularly preferably 360 to 420°C. Furthermore, in order to thoroughly remove the sizing agent adhering to the surface of the glass cloth, the heating time is preferably 24 to 72 hours, more preferably 30 to 60 hours, and even more preferably 40 to 55 hours. Reducing the number of times the glass cloth is rewound or subjected to thermal deoiling treatment can suppress the variation in the dielectric constant of the glass cloth while maintaining good fluff quality, and therefore, one rewind and two thermal deoiling treatments are particularly preferred to achieve both a low variation in the dielectric constant and good fluff quality.

[0072] [Cleaning and opening process] The cleaning and opening step is preferably a step (ultrasonic cleaning) in which ultrasonic waves are applied to the glass cloth after the thermal deoiling step and before the surface treatment step in a liquid to clean mainly the combustion residue of the thermal deoiling from the glass cloth and open it. Preferably, the cleaning and opening step is a step in which the glass cloth is transported in a roll-to-roll manner in a liquid to which ultrasonic waves are applied by an ultrasonic oscillator.

[0073] Although either water or an organic solvent can be used as the liquid for ultrasonic cleaning, it is preferable to use a liquid whose main component is water from the viewpoint of safety and environmental protection. A surfactant or a pH adjuster can also be added to the liquid used for cleaning to improve cleaning efficiency.

[0074] There are no particular restrictions on the temperature of the liquid used in ultrasonic cleaning, but from the viewpoint of enhancing the cleaning effect, it is preferable that the temperature be 5° C. or higher. Furthermore, from the viewpoint of safety, the temperature of the liquid used for cleaning is preferably 60° C. or lower.

[0075] The glass cloth can be cleaned by running it through a liquid to which ultrasonic waves are applied by an ultrasonic oscillator. The line tension acting on the warp yarns during the cleaning process is preferably 30N to 500N / 1m.

[0076] Ultrasonic cleaning can be performed using ultrasonic waves having a frequency of 20 kHz to 200 kHz. The ultrasonic frequency is preferably 20 kHz to 50 kHz, more preferably 20 kHz to 30 kHz. Using ultrasonic waves having a frequency of 20 kHz to 200 kHz is preferable because cleaning can be performed without major defects such as bending of the glass cloth.

[0077] For ultrasonic cleaning, 0.07W / cm 2 Over 3.60W / cm 2 Ultrasonic waves with the following output can be preferably used: A more preferred range of ultrasonic output is 0.14 W / cm 2 More than 2.16W / cm 2 Below that, a more preferable range is 0.21 W / cm2 More than 1.44W / cm 2 Ultrasonic output is 0.07W / cm 2 Above this level, cleaning can be performed satisfactorily, and the ultrasonic output is 3.60W / cm 2 This is preferable because uniform cleaning can be performed without causing any distortion of the mesh.

[0078] The conveying speed of the glass cloth during ultrasonic cleaning is preferably 50 m / min or less, more preferably 40 m / min or less, and particularly preferably 30 m / min or less. If the conveying speed of the glass cloth is 50 m / min or less, the glass cloth or its intermediate product can be satisfactorily cleaned and opened. This is also preferable because it can suppress fluffing and misalignment due to damage during conveyance.

[0079] The liquid used for ultrasonic cleaning usually contains dissolved air, primarily composed of nitrogen and oxygen. The amount of dissolved oxygen (by weight) is preferably 1 ppm to 20 ppm, more preferably 3 ppm to 17 ppm, and even more preferably 4 ppm to 14 ppm. By controlling the amount of dissolved oxygen, it is possible to indirectly control the amount of dissolved gas, and to control the degree to which ultrasonic waves are attenuated by the dissolved gas. A dissolved oxygen amount of 1 ppm or more is preferred because it allows for uniform fiber-opening treatment. A dissolved oxygen amount of 20 ppm or less is preferred because it provides good cleaning action to fiber fabrics. A dissolved oxygen amount in the range of 1 ppm to 20 ppm is preferred because it allows for uniform and good fiber-opening effects.

[0080] [Surface treatment process] The surface treatment step is a step of applying a surface treatment agent such as a silane coupling agent to the glass cloth, and may include, for example, at least one step of a coating step of applying the surface treatment agent to the glass surface and a fixing step of fixing the surface treatment agent to the glass surface by heating and drying. This makes it easier to perform a suitable surface treatment on the glass.

[0081] Methods for applying the surface treatment agent include applying a treatment solution containing the surface treatment agent to the glass cloth or immersing the glass cloth in the treatment solution. Methods for applying the treatment solution to the glass in the coating process include (a) immersing or passing the glass in a treatment solution stored in a bath (hereinafter referred to as the "immersion method"), and (b) applying the treatment solution to the glass using a roll coater, die coater, gravure coater, or the like. When using the immersion method, it is preferable to select a time period for immersing the glass in the treatment solution of 0.5 seconds to 1 minute. Furthermore, when using the immersion method, the glass can be passed through the treatment solution at a conveying speed of 10 to 50 m / min while applying a predetermined tension (e.g., 100 to 250 N) to the glass. Furthermore, after applying the treatment solution to the glass, the solvent contained in the treatment solution can be heated and dried using methods such as hot air or electromagnetic waves.

[0082] The concentration of the surface treatment agent contained in the treatment liquid is preferably 0.1 to 1.0 mass %, more preferably 0.1 to 0.8 mass %, and even more preferably 0.1 to 0.5 mass %, which makes it easier to perform a more suitable surface treatment on the glass.

[0083] In the fixing step, the heat drying temperature is preferably 80° C. or higher, more preferably 90° C. or higher, so that the reaction between the surface treatment agent, for example, a silane coupling agent, and the glass is sufficiently carried out, and the heat drying temperature is preferably 300° C. or lower, more preferably 180° C. or lower, to prevent deterioration of the organic group contained in the surface treatment agent, for example, the silane coupling agent.

[0084] [Surface treatment post-spreading process] As a step of opening the glass filaments bonded by the surface treatment agent, for example, a method of opening the glass cloth with spray water (high-pressure water opening), a vibro washer, ultrasonic water, a mangle, or the like can be adopted. During this opening process, there is a tendency for the yarn width to be wider by reducing the tension applied to the glass cloth. In addition, in order to suppress the generation of fluff in the glass cloth due to the opening process, it is preferable to take measures such as reducing friction with contact members when weaving the glass yarn, optimizing the surface treatment agent, and increasing the amount of adhesion.

[0085] The steps described above do not necessarily have to be performed separately, and multiple steps can be combined into one step. The composition of the glass cloth usually remains unchanged before and after fiber-spreading. The glass cloth manufacturing method can also include any other steps in addition to the steps described above. For example, a slitting step can be included after the fiber-spreading step. If possible, the order of the steps described above can be reversed.

[0086] Prepreg The prepreg of the present disclosure contains the glass cloth of the present disclosure and a matrix resin. This provides a prepreg that can improve the skew characteristics of a printed wiring board. The matrix resin can be a thermosetting resin, a thermoplastic resin, or a combination thereof.

[0087] Examples of thermosetting resins include: a) epoxy resins obtained by reacting a compound having an epoxy group with a compound having at least one of an amino group, a phenol group, an acid anhydride group, a hydrazide group, an isocyanate group, a cyanate group, and a hydroxyl group that reacts with the epoxy group, either without a catalyst or with the addition of a catalyst having reaction catalytic ability, such as an imidazole compound, a tertiary amine compound, a urea compound, or a phosphorus compound, and then curing the resulting mixture; b) radical polymerization curable resins obtained by curing a compound having at least one of an allyl group, a methacryl group, and an acrylic group, using a thermal decomposition catalyst or a photodecomposition catalyst as a reaction initiator; c) maleimide triazine resins obtained by reacting and curing a compound having a cyanate group with a compound having a maleimide group; d) thermosetting polyimide resins obtained by reacting and curing a maleimide compound with an amine compound; and e) benzoxazine resins obtained by crosslinking and curing a compound having a benzoxazine ring through thermal polymerization.

[0088] Examples of thermoplastic resins include polyphenylene ether, modified polyphenylene ether, polyphenylene sulfide, polysulfone, polyether sulfone, polyarylate, aromatic polyamide, polyether ether ketone, thermoplastic polyimide, insoluble polyimide, polyamide imide, LCP, polyester, cycloolefin polymer, and fluororesin.

[0089] The prepreg may further contain an inorganic filler. Examples of inorganic fillers include aluminum hydroxide, zirconium oxide, calcium carbonate, alumina, mica, aluminum carbonate, magnesium silicate, aluminum silicate, silica, talc, short glass fiber, aluminum borate, and silicon carbide. The inorganic filler can be used in combination with a thermosetting resin, a thermoplastic resin, or both.

[0090] <Printed wiring board> The printed wiring board of the present disclosure includes the prepreg of the present disclosure, thereby providing a printed wiring board with excellent skew characteristics and the like.

[0091] Integrated circuits and electronic devices The integrated circuit of the present disclosure includes the printed wiring board of the present disclosure. Furthermore, the electronic device of the present disclosure includes the printed wiring board of the present disclosure. These provide an integrated circuit and electronic device with excellent skew characteristics, etc. Examples of electronic devices include information terminals such as smartphones, and the integrated circuit can be used to improve the performance of electronic devices and enable high-speed communications, such as 5G communications. [Example]

[0092] Next, examples and comparative examples of the present disclosure will be described. The present disclosure is not limited by the following examples and comparative examples. Various evaluation methods will also be described below.

[0093] 《Measurement method》 [Method for measuring the thickness of glass cloth] In accordance with JIS R 3420, Section 7.10, which specifies the general testing method for long glass fiber and products such as glass cloth that use long glass fiber, a micrometer was used to gently rotate the spindle, bringing it into light contact parallel to the measurement surface, and the scale was read after the ratchet made three clicks.

[0094] [Method for measuring basis weight (glass cloth weight)] The basis weight of the cloth was determined by cutting the cloth to a predetermined size and dividing the weight by the sample area. 2 The weight of each glass cloth was determined by cutting it into pieces of the same size.

[0095] [Number of warp and weft filaments and filament diameter (μm)] The number of filaments and the filament diameter of each of the warp and weft yarns were determined by observing a cross-sectional image of the glass yarn. Specifically, a cross-sectional image of the glass yarn as the warp yarn (or the weft yarn) was obtained, and the number of filaments and the filament diameter of the warp yarn (or the weft yarn) were measured in the cross-sectional image. Similarly, the image acquisition of the glass yarn and the measurement of the number of filaments were repeated, and the average values ​​of the five measurements obtained were used as the number of filaments and the filament diameter of the warp yarn (or the weft yarn).

[0096] [Converted thickness] Since the glass cloth is a discontinuous planar body made of air and glass, the converted thickness required for measurement by the resonance method was calculated by dividing the basis weight of each glass cloth by the bulk density of the glass. Converted thickness (μm) = basis weight (g / m 2 ) ÷ bulk density of glass (g / cm 3 )

[0097] [Method for measuring the dielectric constant and dielectric loss tangent of glass cloth] The dielectric loss tangent of each glass cloth was measured in accordance with JIS R1641 / IEC 62562, which specifies methods for measuring the dielectric properties of fine ceramic materials for dielectric substrates, primarily used in microwave circuits, in the microwave band. Specifically, glass cloth samples were sampled to the size required for measurement with each resonator. They were then stored in a constant temperature and humidity oven at 23°C and 50% RH for at least 8 hours to condition the humidity, and then measured using a split cylinder resonator (EM Lab) and an impedance analyzer (Agilent Technologies). A total of 27 samples were taken at locations corresponding to 5%, 10%, 20%, 30%, 50%, 70%, 80%, 90%, and 95% of the total length of the glass cloth roll from the surface in the longitudinal direction, with three samples across the width. From the 27 measurement results, the average values ​​and coefficients of variation of the dielectric constant and dielectric loss tangent at 10 GHz were calculated. The thickness of each sample was measured using the equivalent thickness. Coefficient of variation (%) = standard deviation ÷ mean value × 100

[0098] [Warp width and weft width] The warp width and weft width of the glass cloth were determined by the following method. First, five glass cloth samples measuring 100 mm in the warp direction and 100 mm in the weft direction were cut out from the glass cloth. Each of the cut-out samples was observed vertically at 100x magnification using a macroscope. For each sample, the widths of 250 warp threads (or weft threads) were randomly measured, and the average and standard deviation of the widths of the 250 warp threads (or weft threads) were determined. The determined average value was used as the warp width (or weft width).

[0099] [Measurement of Na ion amount, Mg ion amount, and SO4 ion amount in cleaning solution] The amounts of Na ions, Mg ions, and SO4 ions in the cleaning solution used to wash the glass cloth before thermal deoiling were measured using an ion chromatograph. <Pretreatment conditions> The sample was prepared by diluting it appropriately with distilled water. <Cation ion chromatography conditions> Equipment:Tosoh,IC-2010 Separation column: Tosoh, TSKgel-Super IC-Cation / P (4.6 mm x 150 mm) Separation solution: 2.5mM HNO3 + 0.5mM L-histidine Flow rate: 1.0mL / min Detection: Electrical conductivity Column temperature: 40℃ Injection volume: 30μL <Anion ion chromatography conditions> Equipment:Tosoh,IC-2010 Separation column: Tosoh, TSKgel-Super IC-AZ (4.6 mm x 150 mm) Eluent: 6.3mM NaHCO3+1.7mM Na2CO3 Flow rate: 0.8mL / min Detection: Electrical conductivity Column temperature: 40℃ Injection volume: 30μL

[0100] [Measurement of the amount of Na ions, Mg ions, and SO4 ions adhering to the surface of glass cloth before thermal deoiling] The amounts of Na ions, Mg ions, and SO4 ions adhering to the surface of glass cloth (grey cloth) before thermal deoiling were measured using an ion chromatograph. <Pretreatment conditions> A piece of glass cloth cut to 18 cm x 7 cm was placed in a clean bottle (Wakayama CIC Laboratory Clean Pack Good Boy 100 ml (SCC: ultrapure water washed), AS ONE product number: 7-2214-01). It was then immersed in 10 ml of distilled water at room temperature and subjected to ultrasonic irradiation for 30 minutes. It was then left overnight at room temperature (20°C to 25°C, e.g., 23°C), and then centrifuged (12,000 rpm x 15 minutes). The supernatant, from which the glass cloth-derived impurities had been removed, was used as the sample. The same procedure was performed without the glass cloth, and the resulting supernatant was used as a blank. The amounts of Na ions, Mg ions, and SO 4 ions (ppm) adhering to the glass cloth surface were calculated using the following formula: Amount of each ion attached to the surface of the glass cloth (ppm) = (amount of each ion in the supernatant containing the glass cloth (μg / ml) - amount of each ion in the blank supernatant (μg / ml)) x 10 (ml) / mass of the glass cloth (g) <Cation ion chromatography conditions> Equipment:Tosoh,IC-2010 Separation column: Tosoh, TSKgel-Super IC-Cation / P (4.6 mm x 150 mm) Eluent: 2.5mM HNO3 + 0.5mM L-histidine Flow rate: 1.0mL / min Detection: Electrical conductivity Column temperature: 40℃ Injection volume: 30μL <Anion ion chromatography conditions> Equipment:Tosoh,IC-2010 Separation column: Tosoh, TSKgel-Super IC-AZ (4.6 mm x 150 mm) Eluent: 6.3mM NaHCO3+1.7mM Na2CO3 Flow rate: 0.8 mL / min Detection: Electrical conductivity Column temperature: 40 °C Injection volume: 30 μL

[0101] [Content of each element contained in the glass fiber] The content of each element constituting the glass fiber was determined by the absolute calibration curve method using an ICP mass spectrometer.

[0102] [Content (mass %) of SiO2, B2O3, and Al2O3] In order to reduce impurities (e.g., sizing agents, etc.) adhering to the glass cloth, glass fiber, or its raw materials, the calibration solution was adjusted by the following method. That is, the glass fiber (sample) was weighed and hydrolyzed with sodium hydroxide, and then dissolved with dilute nitric acid to adjust the calibration solution.

[0103] For the obtained calibration solution, the content of silicon was measured using an ICP emission spectrometer (PS3520VDDII manufactured by Hitachi High-Tech Science Corporation), and then the content of SiO2, B2O3, and Al2O3 contained in the sample was determined by converting it to an oxide value.

[0104] [Content (mass %) of CaO, MgO, Li2O, K2O, Na2O, TiO2, P2O5, and SrO] The weighed glass cloth or glass fiber (sample) was thermally decomposed with sulfuric acid, nitric acid, and hydrofluoric acid, and then heated and dissolved with dilute nitric acid to adjust the calibration solution. For the obtained calibration solution, the content in the data of each element was determined by ICP emission spectrometry and converted to an oxide value (ICP emission spectrometer PS3250VDDII manufactured by Hitachi High-Tech Science Corporation, atomic absorption spectrometer ZA3300 manufactured by Hitachi High-Tech Science Corporation).

[0105] [TEX of glass fiber] The TEX of the glass fiber was measured in accordance with R 34:2013. The average value and standard deviation were obtained from the values obtained by performing the TEX measurement operation 15 times.

[0106] <Glass cloth manufacturing example> [Manufacturing of Cross Type P] Glass yarns were woven using an air jet loom to a weave density of 65 warp yarns / 25 mm and 67 weft yarns / 25 mm to obtain a glass cloth P. The glass cloth was woven to a width of 1,300 mm. Glass yarns with an average filament diameter of 5.0 μm, 100 filaments, and a twist of 1.0 Z were used as the warp and weft yarns.

[0107] [Manufacturing of Cross Type Q] Glass yarns were woven using an air jet loom to a weave density of 53 warp yarns / 25 mm and 53 weft yarns / 25 mm to obtain a glass cloth P. The glass cloth was woven to a width of 1,300 mm. Glass yarns with an average filament diameter of 5.0 μm, 200 filaments, and a twist of 1.0 Z were used as the warp and weft yarns.

[0108] [Manufacturing of Cross Type R] Glass cloth R was obtained by weaving glass yarns using an air jet loom to a weave density of 94 warp yarns / 25 mm and 94 weft yarns / 25 mm. The glass cloth was woven to a width of 1,300 mm. Glass yarns with an average filament diameter of 4.0 μm, 50 filaments, and 1.0Z twist were used for the warp and weft.

[0109] [Manufacturing of Cross Type S] Glass cloth S was obtained by weaving glass yarns using an air jet loom to a weave density of 74 warp yarns / 25 mm and 74 weft yarns / 25 mm. The glass cloth was woven to a width of 1,300 mm. Glass yarns with an average filament diameter of 4.0 μm, 100 filaments, and 1.0Z twist were used for the warp and weft.

[0110] [Manufacturing of Cross Type T] Glass cloth T was obtained by weaving glass yarns using an air jet loom to a weave density of 69 warp yarns / 25 mm and 72 weft yarns / 25 mm. The glass cloth was woven to a width of 1,300 mm. Glass yarns with an average filament diameter of 4.5 μm, 100 filaments, and 1.0Z twist were used for the warp and weft.

[0111] [Amount of ions in cleaning solution] The amounts of Na ions and Mg ions in cleaning solution 1 are as shown in the table below. Na ion amount = 1.6 ppm Mg ion amount = 0.0 ppm

[0112] Examples and Comparative Examples Example 1 Glass cloth type P, which was created by selecting only glass yarn A1 with a coefficient of variation of 2.5% or less in the TEX test, was sprayed with high pressure (pressure = 3.0 kg / cm 2 The glass cloth was then subjected to a fiber-opening process using a vibro washer (multi-blade rotor rotation speed = 400 rpm) to wash away the sizing agent adhering to the glass fiber surface and to open the warp and weft yarns (the fiber-opening process before thermal deoiling). The glass cloth was then transported at a line speed of 20 m / min, immersed in a water tank containing cleaning water 1 for 20 seconds, to remove ions adhering to the glass surface. The moisture adhering to the glass cloth was then removed by heating it at 110°C for 10 seconds in a dryer installed on the same line (the cleaning process before thermal deoiling). The resulting glass cloth (2,000 m) was rewound onto a metal core tube and subjected to a thermal deoiling process at 370°C for 30 hours. After the first deoiling process, the glass cloth was rewound onto a metal core tube and subjected to a thermal deoiling process at 370°C for another 30 hours to completely remove the sizing agent from the glass fiber surface (the thermal deoiling process). Next, the glass cloth was run underwater at a conveying tension of 200 N and a line speed of 30 m / min, while being subjected to a frequency of 25 GHz and an output of 0.72 W / cm 2The cloth was irradiated with ultrasonic waves at 3.00 rpm to wash off the residue (cleaning and opening process). Next, a treatment solution was prepared by dispersing 0.3 mass% of 3-methacryloyloxypropyltrimethoxysilane; Z6030 (manufactured by Dow-Toray Industries, Inc.) in pure water adjusted to pH = 3 with acetic acid. The cloth was immersed in the treatment solution, squeezed out, and then heated and dried at 130°C for 60 seconds to fix the silane coupling agent (surface treatment process). The dried cloth was sprayed with 3.0 kg / cm 2 (opening process after surface treatment), and then dried at 130°C for 1 minute to obtain a glass cloth.

[0113] (Examples 2 to 13, Comparative Examples 1 to 9) A glass cloth was obtained in the same manner as in Example 1, except that the items described in the table below were changed as shown in the table below.

[0114] Example 14 In the thermal deoiling pre-opening process, high-pressure spray (pressure = 4.0 kg / cm 2 ) and a vibro washer (multi-blade rotor rotation speed = 500 rpm), the conveying tension was set to 100 N in the cleaning and opening process, and the spray tension was set to 3.5 kg / cm in the post-opening process after surface treatment. 2 A glass cloth was obtained in the same manner as in Example 1, except that high-pressure spreading was carried out at a pressure of 1000 kJ / cm.

[0115] Example 15 Glass cloth type Q, which was created by selecting only glass thread A2 with a coefficient of variation of 1.7% or less in the TEX test, was sprayed with high pressure (pressure = 4.0 kg / cm 2The glass cloth was then subjected to a fiber-opening process using a vibro washer (multi-blade rotor rotation speed = 500 rpm) to wash away the sizing agent adhering to the glass fiber surface and to open the warp and weft yarns (the fiber-opening process before thermal deoiling). The glass cloth was then transported at a line speed of 20 m / min, immersed in a water tank containing cleaning water 1 for 20 seconds, to remove ions adhering to the glass surface. The moisture adhering to the glass cloth was then removed by heating it at 110°C for 10 seconds in a dryer installed on the same line (the cleaning process before thermal deoiling). The resulting glass cloth (2,000 m) was rewound onto a metal core tube and subjected to a thermal deoiling process at 370°C for 30 hours. After the first deoiling process, the glass cloth was rewound onto a metal core tube and subjected to a thermal deoiling process at 370°C for another 30 hours to completely remove the sizing agent from the glass fiber surface (the thermal deoiling process). Next, the glass cloth was run underwater at a conveying tension of 200 N and a line speed of 30 m / min, while being subjected to a frequency of 25 GHz and an output of 0.95 W / cm 2 The cloth was irradiated with ultrasonic waves at 4.5 kg / cm to wash off the residue (cleaning and opening process). Next, a treatment solution was prepared by dispersing 0.3 mass% of 3-methacryloyloxypropyltrimethoxysilane; Z6030 (manufactured by Dow-Toray Industries, Inc.) in pure water adjusted to pH = 3 with acetic acid. The cloth was immersed in the treatment solution, squeezed out, and then heated and dried at 130°C for 60 seconds to fix the silane coupling agent (surface treatment process). The dried cloth was sprayed with 4.5 kg / cm 2 (opening process after surface treatment), and then dried at 130°C for 1 minute to obtain a glass cloth.

[0116] (Examples 16 to 27, Comparative Examples 10 to 18) A glass cloth was obtained in the same manner as in Example 15, except that the items described in the table below were changed as shown in the table below.

[0117] Example 28 In the thermal deoiling pre-opening process, high-pressure spray (pressure = 4.3 kg / cm 2) and a vibro washer (multi-blade rotor rotation speed = 500 rpm), the conveying tension was set to 130 N in the cleaning and opening process, and the spray tension was set to 3.8 kg / cm in the post-opening process after surface treatment. 2 A glass cloth was obtained in the same manner as in Example 15, except that the high-pressure opening was carried out at a pressure of 1000 kJ / cm.

[0118] Example 29 Glass cloth type R, which was created by selecting only glass thread A13 with a coefficient of variation of 1.6% or less in the TEX test, was sprayed with high pressure (pressure = 2.0 kg / cm 2 The glass cloth was then subjected to a fiber-opening process using a vibro washer (multi-blade rotor rotation speed = 450 rpm) to wash away the sizing agent adhering to the glass fiber surface and to open the warp and weft yarns (the fiber-opening process before thermal deoiling). The glass cloth was then transported at a line speed of 20 m / min, immersed in a water tank containing cleaning water 1 for 20 seconds, to remove ions adhering to the glass surface. The moisture adhering to the glass cloth was then removed by heating it at 110°C for 10 seconds in a dryer installed on the same line (the cleaning process before thermal deoiling). The resulting glass cloth (2,000 m) was rewound onto a metal core tube and subjected to a thermal deoiling process at 370°C for 30 hours. After the first deoiling process, the glass cloth was rewound onto a metal core tube and subjected to a thermal deoiling process at 370°C for another 30 hours to completely remove the sizing agent from the glass fiber surface (the thermal deoiling process). Next, the glass cloth was run underwater at a conveying tension of 200 N and a line speed of 30 m / min, while being subjected to a frequency of 25 GHz and an output of 0.55 W / cm 2 The cloth was irradiated with ultrasonic waves at 3.00 rpm to wash off the residue (cleaning and opening process). Next, a treatment solution was prepared by dispersing 0.3 mass% of 3-methacryloyloxypropyltrimethoxysilane; Z6030 (manufactured by Dow-Toray Industries, Inc.) in pure water adjusted to pH = 3 with acetic acid. The cloth was immersed in the treatment solution, squeezed out, and then heated and dried at 130°C for 60 seconds to fix the silane coupling agent (surface treatment process). The dried cloth was sprayed with 3.0 kg / cm 2(opening process after surface treatment), and then dried at 130°C for 1 minute to obtain a glass cloth.

[0119] (Examples 30 to 41, Comparative Examples 19 to 27) A glass cloth was obtained in the same manner as in Example 29, except that the items described in the table below were changed as shown in the table below.

[0120] Example 42 In the thermal deoiling pre-opening process, high-pressure spray (pressure = 3.5 kg / cm 2 ) and a vibro washer (rotation speed of the multi-blade rotor = 500 rpm), the conveying tension was set to 100 N in the cleaning and opening process, and the spray tension was set to 3.0 kg / cm in the post-opening process after the surface treatment. 2 A glass cloth was obtained in the same manner as in Example 29, except that the high-pressure opening was carried out at a pressure of 1000 kJ / cm.

[0121] Example 43 Glass cloth type S, which was created by selecting only glass thread A14 with a coefficient of variation of 1.5% or less in the TEX test, was sprayed with high pressure (pressure = 3.0 kg / cm 2The glass cloth was then subjected to a fiber-opening process using a vibro washer (multi-blade rotor rotation speed = 450 rpm) to wash away the sizing agent adhering to the glass fiber surface and to open the warp and weft yarns (the fiber-opening process before thermal deoiling). The glass cloth was then transported at a line speed of 20 m / min, immersed in a water tank containing cleaning water 1 for 20 seconds, to remove ions adhering to the glass surface. The moisture adhering to the glass cloth was then removed by heating it at 110°C for 10 seconds in a dryer installed on the same line (the cleaning process before thermal deoiling). The resulting glass cloth (2,000 m) was rewound onto a metal core tube and subjected to a thermal deoiling process at 370°C for 30 hours. After the first deoiling process, the glass cloth was rewound onto a metal core tube and subjected to a thermal deoiling process at 370°C for another 30 hours to completely remove the sizing agent from the glass fiber surface (the thermal deoiling process). Next, the glass cloth was run underwater at a conveying tension of 200 N and a line speed of 30 m / min, while being subjected to a frequency of 25 GHz and an output of 0.60 W / cm 2 The cloth was irradiated with ultrasonic waves at 3.00 rpm to wash off the residue (cleaning and opening process). Next, a treatment solution was prepared by dispersing 0.3 mass% of 3-methacryloyloxypropyltrimethoxysilane; Z6030 (manufactured by Dow-Toray Industries, Inc.) in pure water adjusted to pH = 3 with acetic acid. The cloth was immersed in the treatment solution, squeezed out, and then heated and dried at 130°C for 60 seconds to fix the silane coupling agent (surface treatment process). The dried cloth was sprayed with 3.0 kg / cm 2 (opening process after surface treatment), and then dried at 130°C for 1 minute to obtain a glass cloth.

[0122] (Examples 44 to 55, Comparative Examples 28 to 36) A glass cloth was obtained in the same manner as in Example 43, except that the items described in the table below were changed as shown in the table below.

[0123] Example 56 In the thermal deoiling pre-opening process, high-pressure spray (pressure = 4.0 kg / cm 2) and a vibro washer (rotation speed of the multi-blade rotor = 500 rpm), the conveying tension was set to 100 N in the cleaning and opening process, and the spray tension was set to 3.0 kg / cm in the post-opening process after the surface treatment. 2 A glass cloth was obtained in the same manner as in Example 43, except that high-pressure opening was carried out at a pressure of 1000 kJ / cm.

[0124] Example 57 Glass cloth type T, which was created by selecting only glass thread A15 with a coefficient of variation of 1.3% or less in the TEX test, was sprayed with high pressure (pressure = 3.5 kg / cm 2 The glass cloth was then subjected to a fiber-opening process using a vibro washer (multi-blade rotor rotation speed = 480 rpm) to wash away the sizing agent adhering to the glass fiber surface and open the warp and weft yarns (the fiber-opening process before thermal deoiling). The glass cloth was then transported at a line speed of 20 m / min, immersed in a water tank containing cleaning water 1 for 20 seconds, to remove ions adhering to the glass surface. The moisture adhering to the glass cloth was then removed by heating it at 110°C for 10 seconds in a dryer installed on the same line (the cleaning process before thermal deoiling). The resulting glass cloth (2,000 m) was rewound onto a metal core tube and subjected to a thermal deoiling process at 370°C for 30 hours. After the first deoiling process, the glass cloth was rewound onto a metal core tube and subjected to a thermal deoiling process at 370°C for another 30 hours to completely remove the sizing agent from the glass fiber surface (the thermal deoiling process). Next, the glass cloth was run underwater at a conveying tension of 200 N and a line speed of 30 m / min, while being subjected to a frequency of 25 GHz and an output of 0.60 W / cm 2 The cloth was irradiated with ultrasonic waves at 3.00 rpm to wash off the residue (cleaning and opening process). Next, a treatment solution was prepared by dispersing 0.3 mass% of 3-methacryloyloxypropyltrimethoxysilane; Z6030 (manufactured by Dow-Toray Industries, Inc.) in pure water adjusted to pH = 3 with acetic acid. The cloth was immersed in the treatment solution, squeezed out, and then heated and dried at 130°C for 60 seconds to fix the silane coupling agent (surface treatment process). The dried cloth was sprayed with 3.0 kg / cm 2(opening process after surface treatment), and then dried at 130°C for 1 minute to obtain a glass cloth.

[0125] (Examples 58 to 69, Comparative Examples 37 to 45) A glass cloth was obtained in the same manner as in Example 57, except that the items described in the table below were changed as shown in the table below.

[0126] Example 70 In the thermal deoiling pre-opening process, high-pressure spray (pressure = 4.0 kg / cm 2 ) and a vibro washer (multi-blade rotor rotation speed = 520 rpm), the conveying tension was set to 100 N in the cleaning and opening process, and the spray tension was set to 3.0 kg / cm in the post-opening process after surface treatment. 2 A glass cloth was obtained in the same manner as in Example 57, except that high-pressure spreading was carried out at a pressure of 1000 kJ / cm.

[0127] Evaluation Method [Method for evaluating fluff] The glass cloth is placed on a roll-to-roll inspection table with a tension of 100N / 1000mm and illuminated with a halogen lamp, and the glass cloth is visually inspected for 1m. 2 The number of protrusions of 0.8 mm or more per roll was counted. The surface layer and the inner layer of the obtained roll-shaped long glass cloth were evaluated, and the average number of fluffs was evaluated according to the following criteria. A: Number of fluffs: 3 or less B: Number of fluffs: 4 to 8 C: Number of fluffs: 9 to 10 D: Number of fluffs: 11 or more

[0128] [Method for evaluating resin impregnation] The glass cloth was sampled to a size of 50 mm x 50 mm or more. The sample was taken without bending or touching the measurement area. Castor oil (Hayashi Pure Chemical Industries, Ltd., product number: 03001535, static viscosity at 24 °C = 560 mPa s x g / cm) was added at a liquid temperature of 24 °C. 3The evaluation was performed by counting the number of voids in a glass cloth sampled in a 32 mm × 32 mm field of view after the sample was impregnated for a predetermined period of time. A high-precision camera (frame size: 5120 × 5120 pixels) was installed perpendicular to the glass cloth, and an LED light (power flash bar-type light, manufactured by CCS Corporation) was used as a light source. The light was shone from a position directly to the side, 15 cm away from the glass cloth, on both sides of the glass cloth. The number of voids 160 μm or larger present between the glass filaments was then counted within a 32 mm × 32 mm field of view, and the average of three measurements was taken as the number of voids. The voids correspond to areas not impregnated with the matrix resin. Therefore, a glass cloth with a small number of voids indicates that the glass cloth has excellent impregnation properties with the matrix resin.

[0129] Resin impregnation was evaluated according to the following criteria: Five minutes elapsed from the time the glass cloth test piece was immersed in the impregnation varnish until the number of unimpregnated areas was counted. A: Number of unimpregnated areas: 30 or less B: Number of unimpregnated areas: 31 or more and 45 or less C: Number of unimpregnated areas: 45 or more

[0130] [Method for producing laminate] To the glass cloth obtained in the Examples and Comparative Examples, 45 parts by mass of polyphenylene ether (SABIC, Noryl (trade name) SA9000), 10 parts by mass of triallyl isocyanurate, 45 parts by mass of toluene, and 0.6 parts by mass of 1,3-di(tert-butylisopropylbenzene) were added to a stainless steel container and stirred at room temperature for 1 hour to prepare a varnish. The glass cloth was impregnated with the prepared varnish and then dried at 115°C for 1 minute to obtain a prepreg. Ten sheets of the obtained prepreg were stacked, and copper foil (Furukawa Electric Co., Ltd., model: F2-WS, 12 μm) was further stacked on top and bottom, and the resulting mixture was heated at 200°C and 40 kg / cm 2 The mixture was heated and pressed at 100°C for 120 minutes to obtain a laminate.

[0131] [Method for evaluating the heat resistance of laminates] The copper foil of the laminate obtained as described above was removed by etching, and then the laminate was heated and absorbed in a pressure cooker at 133°C for 50 hours. After absorbing water, the laminate was immersed in a solder bath at 288°C for 20 seconds to remove 0.03cm peeling due to peeling at the interface between the glass cloth and the resin. 2 The presence or absence of the above swelling (blistering) was visually confirmed. Six tests were carried out for each laminate. The heat resistance was evaluated as follows. The fewer the swelling of the laminate, the better the heat resistance. A: Two or fewer laminates blistered. B: Three to four laminates blistered. C: Five or more laminates were blistered.

[0132] [Skew characteristic evaluation method] Fifteen microstrip lines with a circuit length of 10 cm were fabricated by etching only the copper foil on one side of the laminate obtained by the above method. The transmission speed of the 15 copper foil wirings (impedance = 100 Ω, wiring angle = 0 degrees) was measured from 10 GHz to 24 GHz, and the ratio of the maximum value to the minimum value was calculated as the skew characteristic of the glass cloth. Skew characteristic = maximum value ÷ minimum value

[0133] [Table 1-1]

[0134] [Table 1-2]

[0135] [Table 1-3]

[0136] [Table 2-1]

[0137] Table 2-2

[0138] Table 2-3

[0139] Table 3

[0140] Table 4

[0141] Table 5

[0142] Table 6

[0143] Table 7

[0144] Table 8

[0145] Table 9

[0146] Table 10

[0147] Table 11

[0148] [Table 12]

[0149] [Table 13]

[0150] [Table 14]

[0151] [Table 15]

[0152] [Table 16]

[0153] [Table 17] [Industrial Applicability]

[0154] The glass cloth of the present disclosure can be used for printed wiring boards, particularly printed wiring boards for high-speed communication. The printed wiring board of the present disclosure can also be used for high-speed communication in integrated circuits and electronic devices such as smartphones.

Claims

1. A glass cloth constructed by using glass yarns made of a plurality of glass filaments as warp yarns and weft yarns, The thickness of the glass cloth is in the range of 26 to 36 μm, The warp width and weft width of the glass cloth are in the ranges of 211 to 300 μm and 326 to 400 μm, respectively; The glass cloth has a coefficient of variation of dielectric constant at 10 GHz measured using a split cylinder resonator of 8.0% or less.

2. A glass cloth constructed by using glass yarns made of a plurality of glass filaments as warp yarns and weft yarns, The thickness of the glass cloth is in the range of 42 to 58 μm, The warp width and weft width of the glass cloth are in the ranges of 267 to 385 μm and 425 to 550 μm, respectively; The glass cloth has a coefficient of variation of dielectric constant at 10 GHz measured using a split cylinder resonator of 8.0% or less.

3. A glass cloth constructed by using glass yarns made of a plurality of glass filaments as warp yarns and weft yarns, The thickness of the glass cloth is in the range of 13 to 19 μm, The warp width and weft width of the glass cloth are in the ranges of 125 to 135 μm and 200 to 240 μm, respectively; The glass cloth has a coefficient of variation of dielectric constant at 10 GHz measured using a split cylinder resonator of 8.0% or less.

4. A glass cloth constructed by using glass yarns made of a plurality of glass filaments as warp yarns and weft yarns, The thickness of the glass cloth is in the range of 17 to 25 μm, The warp width and weft width of the glass cloth are in the ranges of 178 to 198 μm and 310 to 342 μm, respectively; The glass cloth has a coefficient of variation of dielectric constant at 10 GHz measured using a split cylinder resonator of 8.0% or less.

5. A glass cloth constructed by using glass yarns made of a plurality of glass filaments as warp yarns and weft yarns, The thickness of the glass cloth is in the range of 20 to 30 μm, The warp width and weft width of the glass cloth are in the ranges of 176 to 232 μm and 329 to 353 μm, respectively; The glass cloth has a coefficient of variation of dielectric constant at 10 GHz measured using a split cylinder resonator of 8.0% or less.

6. The glass cloth according to any one of claims 1 to 5, wherein the dielectric constant is in the range of 3.8 to 4.

5.

7. The glass fiber contains 45 to 55 mass % of SiO in terms of oxide based on the total mass of the glass fiber. ２ and B in the range of 17 to 27 mass% ２ O ３ and Al in the range of 11 to 21 mass% ２ O ３ and CaO and MgO in a total range of 2.7 to 5.7 mass%, and Li in a total range of 0 to 0.15 mass%. ２ O.K. ２ O and Na ２ The glass cloth according to any one of claims 1 to 5, comprising O.

8. The glass yarn contains, in terms of oxide, 0.15 to 0.45 mass % of TiO based on the total mass of the glass yarn. ２ and P in the range of 2.5 to 7.5 mass%. ２ O ５ and 0 to 0.02 mass % of SrO.

9. The glass fiber contains 48 to 58 mass % of SiO in terms of oxide based on the total mass of the glass fiber. ２ and B in the range of 18 to 28 mass% ２ O ３ and Al in the range of 8 to 18 mass % ２ O ３ and CaO and MgO in a total range of 3.4 to 6.4 mass%, and Li in a total range of 0 to 0.15 mass%. ２ O.K. ２ O and Na ２ The glass cloth according to any one of claims 1 to 5, comprising O.

10. The glass yarn contains 0.9 to 2.9 mass % of TiO in terms of oxide based on the total mass of the glass yarn. ２ and P in the range of 0 to 0.03 mass%. ２ O ５ and 0 to 3 mass % of SrO.

11. The glass fiber contains 48 to 58 mass % of SiO in terms of oxide based on the total mass of the glass fiber. ２ and B in the range of 17 to 27 mass% ２ O ３ and Al in the range of 11 to 21 mass% ２ O ３ and CaO and MgO in a total range of 3.5 to 6.5 mass%, and Li in a total range of 0 to 0.1 mass%. ２ O.K. ２ O and Na ２ The glass cloth according to any one of claims 1 to 5, comprising O.

12. The glass fiber contains TiO in an amount of 0 to 0.3 mass % in terms of oxide based on the total mass of the glass fiber. ２ and P in the range of 0 to 4.2 mass% ２ O ５ and 0 to 1 mass % of SrO.

13. The glass fiber has a SiO content in the range of 47 to 57 mass % in terms of oxide based on the total mass of the glass fiber. ２ and B in the range of 22 to 32 mass% ２ O ３ and Al in the range of 8 to 18 mass % ２ O ３ and CaO and MgO in a total range of 1.4 to 4.4 mass%, and Li in a total range of 0.1 to 1.0 mass%. ２ O.K. ２ O and Na ２ The glass cloth according to any one of claims 1 to 5, comprising O.

14. The glass fiber contains TiO in an amount of 0 to 1 mass % in terms of oxide based on the total mass of the glass fiber. ２ and P in the range of 0 to 0.2 mass% ２ O ５ and SrO in the range of 0 to 0.3 mass %.

15. The glass fiber has a SiO content in the range of 47 to 57 mass % in terms of oxide based on the total mass of the glass fiber. ２ and B in the range of 18 to 28 mass% ２ O ３ and Al in the range of 9 to 19 mass % ２ O ３ and CaO and MgO in a total range of 3.4 to 6.4 mass%, and Li in a total range of 0 to 0.3 mass%. ２ O.K. ２ O and Na ２ The glass cloth according to any one of claims 1 to 5, comprising O.

16. The glass fiber contains, in oxide equivalent, 0.01 to 0.3 mass % of TiO based on the total mass of the glass fiber. ２ and P in the range of 0 to 0.2 mass% ２ O ５ and SrO in the range of 0 to 0.3 mass %.

17. The glass fiber has a SiO content in the range of 47 to 57 mass % in terms of oxide based on the total mass of the glass fiber. ２ and B in the range of 20 to 30 mass% ２ O ３ and Al in the range of 8 to 18 mass % ２ O ３ and CaO and MgO in a total range of 3.0 to 7.0 mass%, and Li in a total range of 0 to 0.3 mass%. ２ O.K. ２ O and Na ２ The glass cloth according to any one of claims 1 to 5, comprising O.

18. The glass fiber contains, in terms of oxide, 1.0 to 5.0 mass % of TiO based on the total mass of the glass fiber. ２ and P in the range of 0 to 0.1 mass% ２ O ５ and SrO in the range of 0 to 0.2 mass %.

19. The glass cloth according to claim 6, wherein the dielectric constant is in the range of 4.0 to 4.

3.

20. The glass cloth according to any one of claims 1 to 5, wherein the glass cloth has a dielectric loss tangent at 10 GHz measured using a split cylinder resonator of 0.0025 or less.

21. The glass cloth according to any one of claims 1 to 5, wherein the glass cloth has a dielectric loss tangent at 10 GHz measured using a split cylinder resonator of 0.0023 or less.

22. The glass cloth according to any one of claims 1 to 5, wherein the glass cloth has a dielectric loss tangent of 0.0020 or less at 10 GHz, as measured using a split cylinder resonator.

23. The glass cloth according to any one of claims 1 to 5, wherein the glass cloth has a dielectric loss tangent at 10 GHz measured using a split cylinder resonator in the range of 0.0010 to 0.0018.

24. The glass cloth according to any one of claims 1 to 5, wherein the glass cloth has a dielectric loss tangent at 10 GHz measured using a split cylinder resonator in the range of 0.0018 to 0.0020.

25. The glass cloth according to any one of claims 1 to 5, wherein the coefficient of variation of the dielectric constant is 6.0% or less.

26. The glass cloth according to any one of claims 1 to 5, wherein the coefficient of variation of the dielectric constant is 4.0% or less.

27. The glass cloth according to any one of claims 1 to 5, wherein the coefficient of variation of the dielectric constant is 2.0% or less.

28. 2. The glass cloth according to claim 1, wherein the warp width and weft width of the glass cloth are in the ranges of 213 to 290 μm and 335 to 390 μm, respectively.

29. 2. The glass cloth according to claim 1, wherein the warp width and weft width of the glass cloth are in the ranges of 215 to 275 μm and 345 to 380 μm, respectively.

30. 2. The glass cloth according to claim 1, wherein the warp width and weft width of the glass cloth are in the ranges of 218 to 260 μm and 350 to 375 μm, respectively.

31. 2. The glass cloth according to claim 1, wherein the standard deviations of the warp width and the weft width of the glass cloth are in the ranges of 16 μm or less and 34 μm or less, respectively.

32. 3. The glass cloth according to claim 2, wherein the warp width and weft width of the glass cloth are in the ranges of 270 to 370 μm and 440 to 540 μm, respectively.

33. 3. The glass cloth according to claim 2, wherein the warp width and weft width of the glass cloth are in the ranges of 275 to 360 μm and 450 to 530 μm, respectively.

34. 3. The glass cloth according to claim 2, wherein the warp width and weft width of the glass cloth are in the ranges of 285 to 350 μm and 460 to 500 μm, respectively.

35. 3. The glass cloth according to claim 2, wherein the standard deviations of the warp width and the weft width of the glass cloth are 26 μm or less and 39 μm or less, respectively.

36. 4. The glass cloth according to claim 3, wherein the warp width and weft width of the glass cloth are in the ranges of 126 to 134 μm and 204 to 236 μm, respectively.

37. 4. The glass cloth according to claim 3, wherein the warp width and weft width of the glass cloth are in the ranges of 127 to 133 μm and 208 to 232 μm, respectively.

38. 4. The glass cloth according to claim 3, wherein the standard deviations of the warp width and the weft width of the glass cloth are in the ranges of 15 μm or less and 24 μm or less, respectively.

39. 5. The glass cloth according to claim 4, wherein the warp width and weft width of the glass cloth are in the ranges of 180 to 196 μm and 313 to 339 μm, respectively.

40. 5. The glass cloth according to claim 4, wherein the warp width and weft width of the glass cloth are in the ranges of 182 to 194 μm and 316 to 336 μm, respectively.

41. 5. The glass cloth according to claim 4, wherein the standard deviations of the warp width and the weft width of the glass cloth are in the ranges of 20 μm or less and 40 μm or less, respectively.

42. 6. The glass cloth according to claim 5, wherein the warp width and weft width of the glass cloth are in the ranges of 183 to 225 μm and 332 to 350 μm, respectively.

43. 6. The glass cloth according to claim 5, wherein the warp width and weft width of the glass cloth are in the ranges of 190 to 218 μm and 335 to 347 μm, respectively.

44. 6. The glass cloth according to claim 5, wherein the standard deviations of the warp width and the weft width of the glass cloth are in the ranges of 20 μm or less and 43 μm or less, respectively.

45. The glass cloth according to any one of claims 1 to 5, wherein the coefficient of variation of TEX of the glass yarn is 4.0% or less.

46. The glass cloth according to any one of claims 1 to 5, wherein the coefficient of variation of TEX of the glass yarn is 3.0% or less.

47. A prepreg comprising the glass cloth according to any one of claims 1 to 5 and a matrix resin.

48. A printed wiring board comprising the prepreg of claim 47.

49. 49. An integrated circuit comprising the printed wiring board of claim 48.

50. An electronic device comprising the printed wiring board of claim 48.

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