Glass yarn, glass cloth, prepreg, and printed wiring board

Abstract

The present invention addresses the problem of providing a glass cloth having excellent flatness and reduced frequency of occurrence of fluff.　The glass cloth of the present invention is composed of glass yarn, wherein the content of silicon (Si) in the glass yarn is 95.0%-100% by mass in terms of silicon dioxide (SiO2), and the Snarl value of the glass yarn is 400 mm or less. Alternatively, the glass cloth of the present invention is composed of glass yarn, wherein the bulk dielectric loss tangent of glass constituting the glass yarn at 10 GHz is 0.001 or less, and the Snarl value of the glass yarn is 400 mm or less.

Description

Glass thread, glass cloth, prepreg, and printed wiring boards

[0001] The present disclosure relates to glass yarn, glass cloth, prepreg, printed wiring boards, and the like.

[0002] Currently, the performance of information terminals such as smartphones is improving, and high-speed communications, as exemplified by 5G communications, are advancing. Against this background, not only is the heat resistance of printed wiring boards, particularly those used for high-speed communications, improved, but also further improvements in the dielectric properties of their insulating materials (e.g., lower dielectric loss tangent) are desired. Similarly, improvements in the dielectric properties of prepregs used as insulating materials for printed wiring boards, and glass yarns and glass cloths contained in the prepregs, are also desired.

[0003] In order to reduce the dielectric constant of insulating materials, a method for constructing insulating materials using a prepreg in which a low dielectric resin (hereinafter referred to as a "matrix resin") is impregnated into glass cloth is known (for example, Patent Documents 1 and 2). Patent Documents 1 and 2 describe that polyphenylene ether terminally modified with vinyl groups or methacryloxy groups is advantageous in terms of low dielectric properties and heat resistance, and that this modified polyphenylene ether is used as a matrix resin.

[0004] Furthermore, for the purpose of improving the flatness of glass cloth and stabilizing the signal transmission speed, it has been reported to use a glass yarn having a bending point with a curvature radius of 5 mm or less and a bending angle of 120 degrees or less, and a bending density of 0.10 pieces / cm or less (see, for example, Patent Document 3). Patent Document 3 states that a silica glass ingot having a desired roundness can be obtained by cylindrically grinding a silica glass ingot using a cylindrical grinder, and that glass filaments, which are the raw material for glass yarn, can be obtained by using such a silica glass ingot having the desired roundness.

[0005] Also, an invention has been reported that includes the requirements of surface-treating glass cloth with a silane coupling agent and adjusting the ignition loss of the glass cloth to 0.13 to 0.40 mass % (see, for example, Patent Document 4). Patent Document 4 discloses a glass cloth containing silicon dioxide (SiO２ ) for a glass cloth obtained by weaving glass yarns made of glass filaments having a composition of 98 to 100 mass %, the document states that by adjusting the ignition loss value of the glass cloth to the above range, it is possible to improve the insulation reliability and also to suppress the generation of fluff in the glass cloth.

[0006] Furthermore, an invention described in Patent Document 5 has been reported as an invention in the same technical field.

[0007] International Publication No. 2019 / 065940 International Publication No. 2019 / 065941 Japanese Patent Application Laid-Open No. 2020-90432 Japanese Patent Application Laid-Open No. 2018-127747 International Publication No. 2022 / 215288

[0008] However, the invention described in Patent Document 3 has a problem in that the yield is reduced because cylindrical grinding of the silica glass ingot is required. Therefore, there has been a strong demand for a technology to improve the flatness of glass cloth without requiring special processing such as cylindrical grinding.

[0009] Furthermore, as described in Patent Document 4, in an invention that requires surface treatment of glass cloth with a silane coupling agent, if the silane coupling agent unintentionally remains on the glass surface, there is a problem that the dielectric loss tangent of the glass cloth increases (see, for example, the above-mentioned Patent Document 5). Therefore, there has been a strong demand for the development of a technology for suppressing fluffing of glass cloth by a means other than adjusting the ignition loss value.

[0010] An object of the present disclosure is to provide a glass cloth having excellent flatness and a reduced frequency of fuzz generation. Another object of the present disclosure is to provide a glass cloth manufacturing method, a glass yarn package, and a glass yarn that can provide such a glass cloth. Another object of the present disclosure is to provide a prepreg, a printed wiring board, an integrated circuit, and an electronic device that use such a glass cloth.

[0011]

[0013] Examples of embodiments of the present disclosure are as follows: [1] A glass cloth made of glass yarns, wherein the silicon (Si) content in the glass yarns is silicon dioxide (SiO ２ ) and the Snarl index of the glass yarn is 400 mm or less. [2] A glass cloth composed of glass yarns, wherein the bulk dielectric dissipation factor at 10 GHz of the glass constituting the glass yarns is in the range of 0.001 or less and the Snarl index of the glass yarns is 400 mm or less. [3] The glass cloth according to item 1 or 2, wherein the Snarl index of the glass yarns is 70 mm or more. [4] The glass yarns are in the ranges described in the following formulas (A), (B), and (C): (A) x + y + z = 100 mass % (B) x ≥ 99.5 mass % (C) 0.0003 ppm ≤ y ≤ 0.50 ppm x: silicon dioxide (SiO ２ ) converted into y: silicon content, y: total content of uranium and thorium, z: total content of elements other than silicon, uranium, and thorium. [5] The glass cloth according to item 1 or 2, comprising glass yarns satisfying the following formula: [x]: silicon content when converted into y ... 3-n SiY n...(1) (in formula (1), X is an organic functional group having at least one of an amino group and an unsaturated double bond group having radical reactivity; each Y is independently an alkoxy group; n is an integer of 1 to 3; and each R is independently a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group). [9] The glass cloth according to item 8, wherein X in formula (1) is an organic functional group that does not form a salt with an ionic compound.

[10] The glass cloth according to item 8 or 9, wherein X in formula (1) does not contain an amine and / or an ammonium cation.

[11] The glass cloth according to any one of items 8 to 10, wherein X in formula (1) is an organic functional group having a methacryloxy group and / or an acryloxy group.

[12] The glass cloth according to any one of items 1 to 11, wherein the absolute value of the number of twists of the glass yarn is in the range of 0.5 to 1.5 turns / 25 mm.

[13] The glass cloth according to any one of items 1 to 12, wherein the glass cloth has the glass yarns as warp yarns and weft yarns, and the absolute value of the difference in the number of twists between the warp yarns and the weft yarns is in the range of 0.01 to 0.70 turns / 25 mm.

[14] The glass cloth according to any one of items 1 to 13, wherein the thickness of the glass cloth is 60 μm or less.

[15] The glass cloth according to any one of items 1 to 14, wherein the glass cloth is used for a printed wiring board.

[16] A prepreg comprising the glass cloth according to any one of items 1 to 15 and a thermosetting resin.

[17] A printed wiring board comprising the prepreg according to item 16.

[18] An integrated circuit comprising the printed wiring board according to item 17.

[19] An electronic device comprising the printed wiring board according to item 17.

[20] A method for producing a glass cloth, wherein the silicon (Si) content in the glass yarns is less than or equal to the silicon dioxide (SiO ２) in the range of 95.0 to 100 mass% in terms of the bulk dielectric loss tangent at 10 GHz of the glass constituting the glass yarn, and the Snarl index of the glass yarn is 400 mm or less.

[21] A method for producing a glass cloth, comprising a step of producing a glass cloth using the glass yarn, wherein the bulk dielectric loss tangent at 10 GHz of the glass constituting the glass yarn is 0.001 or less, and the Snarl index of the glass yarn is 400 mm or less.

[22] A method for producing a glass cloth according to item 20 or 21, wherein the Snarl index of the glass yarn is 70 mm or more.

[23] The glass yarn has a content of x + y + z in the ranges defined by the following formulas (A), (B), and (C): (A) x + y + z = 100 mass% (B) x ≥ 99.5 mass% (C) 0.0003 ppm ≤ y ≤ 0.50 ppm, ２ ), y: the silicon content when converted to y: the total content of uranium and thorium, z: the total content of elements other than silicon, uranium, and thorium.

[24] A method for producing a glass cloth according to any one of items 20 to 23, comprising: a step of warping the glass yarns used as warp yarns (warp warping step), and a step of weaving using the glass yarns (weaving step), wherein the absolute value of the number of twists of the glass yarns is adjusted to a range of 0.5 to 1.5 turns / 25 mm in the warp warping step and / or the weaving step.

[25] A method for producing a glass cloth according to item 24, wherein the glass cloth has the glass yarns as warp yarns and weft yarns, and comprises a step of adjusting the number of twists of the weft yarns so that the absolute value of the difference in the number of twists between the warp yarns and the weft yarns is within a range of 0.01 to 0.70 turns / 25 mm.

[26] The method for producing a glass cloth according to item 24 or 25, wherein the warp warping step and / or the weaving step are carried out using glass yarns having a value obtained by dividing the yarn width of the glass yarn by TEX in the range of 10 to 30.

[27] A glass yarn package having a core material and glass yarns wound around the core material, wherein the silicon (Si) content in the glass yarns is 0.01 to 0.02% by weight of silicon dioxide (SiO ２) and the Snarl index of the glass yarn is 400 mm or less.

[28] The glass yarn package according to item 27, wherein the Snarl index of the glass yarn is 70 mm or more.

[29] The glass yarn is in the ranges described in the following formulas (A), (B), and (C): (A) x + y + z = 100 mass % (B) x ≧ 99.5 mass % (C) 0.0003 ppm ≦ y ≦ 0.50 ppm x: silicon dioxide (SiO ２ ) y: the total content of uranium and thorium z: the total content of elements other than silicon, uranium, and thorium.

[30] The glass yarn package according to any one of items 27 to 29, wherein the absolute value of the number of twists of the glass yarn is in the range of 0.5 to 1.5 turns / 25 mm.

[31] The glass yarn package according to item 27 or 28, wherein the value obtained by dividing the yarn width of the glass yarn by TEX is in the range of 10 to 30.

[32] A glass yarn used for weaving a glass cloth, wherein the silicon (Si) content in the glass yarn is in the range of 10 to 30 based on silicon dioxide (SiO ２ ) and the Snarl index of the glass yarn is 95.0 to 100 mass% in terms of SiO ), and the Snarl index of the glass yarn is 400 mm or less.

[33] The glass yarn according to item 32, wherein the Snarl index of the glass yarn is 70 mm or more.

[34] The glass yarn is in the ranges described in the following formulas (A), (B), and (C): (A) x + y + z = 100 mass% (B) x ≧ 99.5 mass% (C) 0.0003 ppm ≦ y ≦ 0.50 ppm x: silicon dioxide (SiO ２) converted into a silicon content, y: the total content of uranium and thorium, z: the total content of elements other than silicon, uranium, and thorium.

[35] The glass fiber according to item 34, wherein y, representing the total content of uranium and thorium, is in the range of 0.0003 to 0.0010 ppm.

[36] The glass fiber according to item 34, wherein y, representing the total content of uranium and thorium, is in the range of more than 0.0010 and not more than 0.0015 ppm.

[37] The glass fiber according to item 34, wherein y, representing the total content of uranium and thorium, is in the range of more than 0.0015 and not more than 0.0018 ppm.

[38] The glass fiber according to item 34, wherein y, representing the total content of uranium and thorium, is in the range of more than 0.0018 and not more than 0.0035 ppm.

[39] The glass fiber according to item 34, wherein y, representing the total amount of uranium and thorium content, is in the range of more than 0.0035 and not more than 0.0040 ppm.

[40] The glass fiber according to item 34, wherein y, representing the total amount of uranium and thorium content, is in the range of more than 0.0040 and not more than 0.09 ppm.

[41] The glass fiber according to item 34, wherein y, representing the total amount of uranium and thorium content, is in the range of more than 0.09 and not more than 0.12 ppm.

[42] The glass fiber according to item 34, wherein y, representing the total amount of uranium and thorium content, is in the range of more than 0.12 and not more than 0.50 ppm.

[43] The glass fiber according to any one of items 32 to 42, wherein the Snarl index of the glass fiber is in the range of 330 to 400 mm.

[44] The glass fiber according to any one of items 32 to 42, wherein the Snarl index of the glass fiber is in the range of 300 to 329 mm.

[45] The glass fiber according to any one of items 32 to 42, wherein the Snarl index of the glass fiber is in the range of 220 to 299 mm.

[46] The glass fiber according to any one of items 32 to 42, wherein the Snarl index of the glass fiber is in the range of 200 to 219 mm.

[47] The glass fiber according to any one of items 32 to 42, wherein the Snarl index of the glass fiber is in the range of 125 to 199 mm.

[48] ​​The glass fiber according to any one of items 32 to 42, wherein the Snarl index of the glass fiber is in the range of 110 to 124 mm.

[49] The glass fiber according to any one of items 32 to 42, wherein the Snarl index of the glass fiber is 110 mm or less.

[0012] According to the present disclosure, it is possible to provide a glass cloth having excellent flatness and a reduced frequency of fuzz generation. Furthermore, according to the present disclosure, it is possible to provide a glass cloth manufacturing method, a glass yarn package, and a glass yarn that can provide such a glass cloth. Furthermore, according to the present disclosure, it is possible to provide a prepreg, a printed wiring board, an integrated circuit, and an electronic device that use such a glass cloth.

[0013] Fig. 1 is a schematic diagram for explaining a method for measuring the amount of warpage in the present disclosure. Fig. 2 is a schematic diagram for explaining a method for measuring the amount of warpage in the present disclosure.

[0014] Hereinafter, examples of embodiments of the present disclosure will be described. However, the present disclosure is not limited to the following embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0015] In this specification, when a plurality of structures represented by the same symbol exist in the same formula, the structures may be independently selected and may be the same or different from each other, unless otherwise specified. When a plurality of structures represented by the same symbol exist in different formulas, the structures may be independently selected and may be the same or different from each other, unless otherwise specified. Furthermore, in this specification, the upper or lower limit of a numerical range described in stages may be replaced by the upper or lower limit of a corresponding numerical range described in another stage, and may further be replaced by a corresponding value described in the examples. Furthermore, in this specification, the term "step" is included not only in the case of an independent step, but also in the case of a step that cannot be clearly distinguished from other steps, as long as the function of that step is achieved. In the contents shown in the drawings, the scale, shape, and length may be exaggerated for clarity.

[0016] <Glass Cloth> <Overall Configuration> The glass cloth of the present disclosure is a glass cloth made of glass yarns, and the silicon (Si) content in the glass yarns is silicon dioxide (SiO ２ ) is 95.0 to 100 mass % and the Snarl index of the glass yarn is in the range of 400 mm or less.

[0017] The glass cloth of the present disclosure is a glass cloth made of glass yarns, in which the bulk dielectric loss tangent at 10 GHz of the glass making up the glass yarns is in the range of 0.001 or less, and the Snarl index of the glass yarns is in the range of 400 mm or less.

[0018] The present inventors have discovered glass fibers that are advantageous for improving the dielectric properties of glass cloth, such as the following (1) and / or (2): (1) a glass fiber having a silicon (Si) content of silicon dioxide (SiO ２ The inventors have found that, in the case of (1) a glass yarn containing 95.0 to 100 mass % of glass fibers in a range of 10 GHz to 100 GHz, when converted into a dielectric constant of 0.001 or less, residual stress is likely to occur in a glass cloth obtained by using the glass yarn, and that such glass yarns tend to have a high Snarl index. The inventors have further found that a glass cloth using glass yarns with a higher Snarl index has a more adverse effect on the flatness (degree of warping) of the glass cloth.

[0019] Here, snare refers to the twist that occurs in a twisted yarn as the yarn tries to untwist, and in this specification, the higher the snare index, the more likely it is that snare will occur. In JIS-L-0210:1981, 3.1, item 1113, snare is defined as "the tangle of yarns that occurs due to the twist when the twisted yarn is relaxed." In this regard, the effect of the snare index on the quality of glass cloth has not been studied in the past.

[0020] Furthermore, the present inventors have found that, with respect to a glass yarn (referred to as a "glass yarn package" in the present disclosure) in a state in which the glass yarn is wound around a core material (in one embodiment, a bobbin), the higher the Snarl index of the glass yarn, the more likely the glass yarn is to be unwound while rubbing against the surface of the bobbin when released from the bobbin, and as a result, the more likely fluff is to occur on the surface of a glass cloth obtained using the glass yarn. In particular, the present inventors have also found that, in the process of warping glass yarns used as warp yarns for a glass cloth (warp warping process), the unwinding speed of the glass yarns is slower than in the process of weaving using the glass yarns (weaving process), and therefore the glass yarns tend to be more likely to rub against the surface of the bobbin.

[0021] Therefore, the present inventors conducted studies from the viewpoint of reducing the Snarl index and found that the Snarl index can be adjusted by the spinning conditions of the glass yarn. In one preferred embodiment, a glass yarn is produced from a glass rod having a silicon content of 99.5 mass% or more, and after the glass rod is heated and drawn, an annealing treatment can be performed to reduce the residual stress generated in the glass yarn (in one embodiment, to eliminate the residual stress). According to the present disclosure, a glass cloth can be provided that uses glass yarn with a controlled Snarl index, and that can improve flatness and reduce the frequency of fluff generation.

[0022] The weight of the glass cloth (mass of the glass cloth) is preferably 8 to 250 g / m 2 and more preferably 8 to 100 g / m 2 and more preferably 8 to 80 g / m 2 and particularly preferably 8 to 50 g / m 2 When the basis weight of the glass cloth is within the above range, the effects of the present disclosure are easily obtained.

[0023] The thickness of the glass cloth is preferably 60 μm or less, more preferably 55 μm or less, and even more preferably 50 μm or less. When the thickness of the glass cloth is within the above range, the effects of the present disclosure are easily obtained. The thickness of the glass cloth may be more than 0 μm, 5 μm or more, or 5 μm or more.

[0024] <Glass Yarn> The Snarl index of glass yarn is in the range of 400 mm or less. When a twist is applied to a yarn, an untwisting torque is generated that tries to undo the twist, and at this time, twisting of the yarn may occur. Such twisting is called "snarl" in this specification, and the Snarl index as described in JIS L1095, for example, can be used as an index of the likelihood of snarling.

[0025] It is known that glass yarns (glass threads) suitable for use in printed wiring boards, such as E-glass yarn, can be obtained by extruding molten glass in a melting furnace through a nozzle to obtain glass filaments with a diameter of several μm, and then processing these filaments.

[0026] On the other hand, silicon (Si) content is silicon dioxide (SiO ２ Silica glass having a SiO2 content of 95.0 to 100% by mass in terms of SiO2 has a melting point much higher than other glasses. Therefore, it differs from the E-glass yarn and the like in that the raw material, glass filaments, are obtained by heating and stretching a quartz glass rod (quartz glass ingot). By heating and stretching a quartz glass rod, the siloxane bonds that make up the glass are oriented in the stretching direction, which tends to cause residual stress in the resulting glass filaments.

[0027] The present inventors have found that this residual stress causes "snarling," which was not recognized as a problem in conventional glass yarns, and adversely affects the fluff quality and flatness of the glass cloth. Specifically, the higher the snarling index of a glass yarn, the more likely the glass yarn is to come into contact with the surface of a bobbin when unwound from the bobbin during warping of the glass cloth, and as a result, fluff is more likely to occur on the surface of the glass cloth. Furthermore, a glass yarn with a high snarling index tends to cause stronger undulations in the glass cloth, and therefore is more likely to adversely affect the flatness (warping) of the glass cloth.

[0028] Regarding "snarl," which has not been recognized as a problem in conventional glass yarns, in order to reduce the snarl index of quartz glass yarns more than ever before, it is preferable to anneal the glass filaments or glass yarns immediately after heating and drawing them. This method is relatively simple and is advantageous in providing glass cloth with excellent fluff quality and flatness.

[0029] As a result of studies, the present inventors have found that by setting the Snail index of the glass yarn to 400 mm or less, it is possible to perform warp warping while reducing the frequency of fluffing on the surface of the glass cloth. From the viewpoint of easily achieving the effects of the present disclosure, the Snail index of the glass yarn is preferably 70 to 400 mm. From the viewpoint of suppressing fluffing on the glass surface, the upper limit of the Snail index is preferably 380 mm or less, more preferably 370 mm or less, even more preferably 350 mm or less, still more preferably 330 mm or less, and particularly preferably 310 mm or less, for example, 300 mm or less, 250 mm or less, 200 mm or less, 150 mm or less, or 100 mm or less. The lower limit of the Snail index, which can be arbitrarily combined with these upper limits, may be 70 mm or more, 100 mm or more, 150 mm or more, 200 mm or more, 250 mm or more, 300 mm or more, or 330 or more. For example, from the viewpoint of easily obtaining the effects of the present disclosure, the Snail index of the glass yarn is preferably in the range of 330 to 400 mm, 300 to 329 mm, or 220 to 299 mm; from the viewpoint of placing some importance on fluff on the surface of the glass cloth in addition to the productivity of the glass yarn, the range of 200 to 219 mm is preferred; from the viewpoint of placing more importance on fluff on the surface of the glass cloth in addition to the productivity of the glass yarn, the range of 125 to 199 mm is preferred; from the viewpoint of placing even more importance on fluff on the surface of the glass cloth in addition to the productivity of the glass yarn, the range of 110 to 124 mm is even more preferred; and from the viewpoint of placing particular importance on fluff on the surface of the glass cloth in addition to the productivity of the glass yarn, the range of 110 mm or less, for example, the range of 70 to 110 mm or less is particularly preferred.

[0030] From the viewpoint of easily obtaining the effect of reducing the Snarl index by annealing treatment, the silicon (Si) content in the glass yarn is silicon dioxide (SiO ２) is preferably 99.5% by mass or more, more preferably 99.6% by mass or more, even more preferably 99.7% by mass or more, still more preferably 99.8% by mass or more, particularly preferably 99.9% by mass or more, and particularly preferably 99.95% by mass or more.

[0031] Glass cloth is obtained by weaving glass yarns (e.g., glass yarns consisting of a plurality of glass filaments) as warp and weft yarns. Examples of the weave structure of the glass cloth include plain weave, sash weave, satin weave, and twill weave, and among these, plain weave structure is preferred.

[0032] The placement density of the warp and weft yarns is preferably 10 to 120 yarns / inch (= 10 to 120 yarns / 25 mm), more preferably 40 to 100 yarns / inch. If the placement density is within the above range, the effects of the present disclosure are easily obtained. The placement densities of the warp and weft yarns may be different from each other.

[0033] The glass yarns constituting the glass cloth can be obtained by including so-called "low dielectric glass" as a raw material. The glass yarns satisfy the ranges described in (A), (B), and (C): (A) x + y + z = 100 mass% (B) x ≥ 99.5 mass% (C) 0.0003 ppm ≤ y ≤ 0.50 ppm, where x is silicon dioxide (SiO ２ ) y: silicon content when converted to y, y is the total content of uranium and thorium, z: the total content of elements other than silicon, uranium, and thorium. It is more preferable that the glass yarn satisfies the ranges described in (A), (B), and (C). By using glass yarns that satisfy the ranges described in (A), (B), and (C), it is easy to improve, for example, the dielectric properties of the obtained glass cloth.

[0034] From the viewpoint of improving the dielectric properties of the obtained glass cloth, the range of x is preferably 99.6 mass % or more, more preferably 99.7 mass % or more, even more preferably 99.8 mass % or more, still more preferably 99.9 mass % or more, and particularly preferably 99.95 mass % or more.

[0035] The range of y is preferably the range described in (C) above, i.e., 0.0003 ppm≦y≦0.50 ppm. Uranium (U) and thorium (Th) in the glass filament can cause memory malfunctions in electronic devices, so the lower their total content, the better. As a result of studies by the present inventors, although the mechanism of action is not entirely clear, they have found that the total content of uranium and thorium has an effect on controlling the residual stress in the glass filament and adjusting the Snarl index. That is, the present inventors have found that, as a phenomenon specific to producing a glass filament from a glass rod having a silicon content of 99.5% by mass or more, the residual stress in the glass filament is easily reduced if the total content of uranium and thorium is 0.0003 ppm or more. In this regard, the inventors have also clarified that glass yarns with high residual stress have a strong untwisting force and therefore tend to have a high Snarl index, and that glass cloths made using such glass yarns are prone to warping and poor flatness.

[0036] From the above viewpoint, it has been a common technical understanding to keep the total content of uranium (U) and thorium (Th) as low as possible. However, from the viewpoint of improving the flatness of the glass cloth, the total content of uranium and thorium has not been deliberately adjusted to be within an appropriate range. After extensive research, the present inventors have found that the higher the total content of uranium and thorium in the glass yarn, the more easily the effect of the annealing treatment for reducing the Snarl index of the glass yarn is exerted. From the viewpoint of easily achieving the effects of the present disclosure, the range of y can be 0.0003 ppm≦y≦0.50 ppm, and the lower limit is preferably 0.001 ppm or more, more preferably 0.003 ppm or more, even more preferably 0.005 ppm or more, still more preferably 0.007 ppm or more, and particularly preferably 0.01 ppm or more. The upper limit of y, which can be arbitrarily combined with these lower limits, is preferably 0.45 ppm or less, more preferably 0.40 ppm or less, even more preferably 0.35 ppm or less, even more preferably 0.30 ppm or less, and particularly preferably 0.25 ppm or less. If y is in the range of 0.0003 ppm or more, it is easy to avoid a situation in which the residual stress generated during heating and drawing is high due to the silicon content in the glass being too high, and as a result, it is easy to control the Snarl index of the glass yarn to a range of 400 mm or less. On the other hand, if y is in the range of 0.50 ppm or less, it is easy to avoid the influence of uranium and thorium, for example, the problem of memory malfunction in electronic devices containing glass yarn as components. Furthermore, from the viewpoint of easily improving memory malfunction performance, y is preferably in the range of 0.0003 to 0.0010 ppm.From the viewpoint of easily reducing the snarling of the glass yarn in addition to improving the malfunction performance of the memory, y is more preferably in the range of more than 0.0010 and not more than 0.0015 ppm; from the viewpoint of easily reducing the snarling of the glass yarn in addition to improving the malfunction performance of the memory, y is more preferably in the range of more than 0.0015 and not more than 0.0018 ppm; from the viewpoint of easily reducing the snarling of the glass yarn in addition to improving the malfunction performance of the memory, y is even more preferably in the range of more than 0.0018 and not more than 0.0035 ppm; from the viewpoint of easily reducing the snarling of the glass yarn in addition to improving the malfunction performance of the memory and facilitating the refining and processing of the quartz rod, y is more preferably in the range of more than 0.0035 and not more than 0.0040 ppm; from the viewpoint of easily reducing the snarling of the glass yarn in addition to improving the malfunction performance of the memory and facilitating the refining and processing of the quartz rod, y is particularly preferably in the range of more than 0.0040 and not more than 0.09 ppm.

[0037] <Bulk dielectric loss tangent> In this specification, the bulk dielectric loss tangent refers to the dielectric loss tangent of the raw material of a glass cloth measured at 10 GHz using a split cylinder resonator. The raw material of the glass cloth may be, for example, glass species, glass filaments, glass threads, etc. The bulk dielectric loss tangent of the glass raw material constituting the glass cloth can be measured by using a glass plate having a thickness of 300 μm or less and having the same type and composition as the glass raw material, in the same manner as the method for measuring the dielectric loss tangent of the glass cloth.

[0038] From the viewpoint of easily obtaining the effects of the present disclosure, the bulk dielectric loss tangent at 10 GHz is preferably 0.0009 or less, more preferably 0.0008 or less, even more preferably 0.0007 or less, still more preferably 0.0005 or less, even more preferably 0.0004 or less, particularly preferably 0.0003 or less, and most preferably 0.0002 or less. The bulk dielectric loss tangent may be greater than 0.

[0039] <Average Opening Degree of Glass Cloth> The average opening degree of the glass cloth is preferably 38% or more or more than 40%, more preferably more than 43%, even more preferably more than 46%, more than 50%, more than 53%, more than 56%, or more than 60%, and particularly preferably more than 65%. If the average opening degree of the glass cloth is 38% or more, it is easy to prevent air bubbles called voids from remaining in the bundle of glass yarns when producing a prepreg or a printed wiring board containing the same, and as a result, it is hard to adversely affect the soldering heat resistance, insulation reliability, etc. Furthermore, if the average opening degree of the glass cloth is 38% or more, it is hard to be affected by the snare of the glass yarns, and therefore it is easy to ensure the flatness of the glass cloth even if a glass yarn with a relatively high snare index is used.

[0040] <Silane Coupling Agent> The glass yarns (including glass filaments) constituting the glass cloth are preferably surface-treated with a silane coupling agent. That is, in one embodiment, the surface treatment agent for the glass yarns contains a silane coupling agent. Examples of the silane coupling agent include those represented by the following formula (1): X(R) 3-n SiY n ...(1) {in formula (1), X is an organic functional group having at least one of an amino group and an unsaturated double bond group having radical reactivity, each Y is independently an alkoxy group, n is an integer of 1 or more and 3 or less, and R is a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group}.

[0041] Conventionally, the causes of an increase in the dielectric tangent of glass cloth have been considered to be (i) trace amounts of thermally oxidized degradation products of sizing agents that remain physically attached to the glass yarn surface, and (ii) residues or modified products of surface treatment agents that physically adhere without forming chemical bonds with the glass surface and cannot be reduced by washing with water. From the viewpoint of suppressing the generation of (i) thermally oxidized degradation products and / or (ii) residues or modified products, X in formula (1) is preferably an organic functional group that does not form a salt with an ionic compound. Furthermore, from the viewpoint of reactivity with the matrix resin, X in formula (1) is more preferably an organic functional group having a methacryloxy group and / or an acryloxy group. From the viewpoint of easily achieving the effects of the present disclosure, X in formula (1) preferably does not contain amines such as primary amines, secondary amines, and tertiary amines, and preferably does not contain ammonium cations such as quaternary ammonium cations.

[0042] With regard to Y in the above formula (1), the alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms (1, 2, 3, 4 or 5 carbon atoms) from the viewpoint of stabilizing the treatment of the glass cloth.

[0043] As a surface treatment agent, the silane coupling agent represented by formula (1) may be used alone or in combination with two or more silane coupling agents having different X's in formula (1). As the silane coupling agent represented by formula (1), for example, vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 5-hexenyltrimethoxysilane, etc. may be used alone or as a mixture thereof.

[0044] The molecular weight of the silane coupling agent is preferably 100 to 600, more preferably 150 to 500, and even more preferably 200 to 450. It is particularly preferable to use two or more silane coupling agents with different molecular weights. Treating the glass fiber with two or more silane coupling agents with different molecular weights increases the density of the treatment agent on the glass surface, which tends to further improve the reactivity with the matrix resin.

[0045] From the viewpoint of not inhibiting reactivity with resins, the silane coupling agent is preferably nonionic. Among nonionic silane coupling agents, silane coupling agents having at least one group selected from the group consisting of vinyl groups, methacryloxy groups, and acryloxy groups are preferred, and silane coupling agents having methacryloxy groups and / or acryloxy groups are particularly preferred. Ensuring reactivity with resins makes it easier to improve the heat resistance and reliability of printed wiring boards.

[0046] In one embodiment, X in formula (1) is an organic functional group having at least one of the unsaturated double bond group and an amino group. Therefore, not only an embodiment in which X has both the unsaturated double bond group and the amino group, but also an embodiment in which X has the unsaturated double bond group but not the amino group, and an embodiment in which X does not have the unsaturated double bond group but has the amino group are all included in the scope of formula (1). However, X in formula (1) is preferably the unsaturated double bond group, and preferably does not contain an amino group.

[0047] <Ignition Loss Value of Glass Cloth> From the viewpoint of reducing the dielectric loss tangent of the glass cloth, the ignition loss value of the glass cloth is preferably 0.010% by mass or more but less than 0.180% by mass, preferably 0.010% by mass or more but less than 0.174% by mass, more preferably 0.010% by mass or more but less than 0.150% by mass, and even more preferably 0.010% by mass or more but less than 0.130% by mass. If the ignition loss value is less than 0.180% by mass, it is easy to avoid a situation in which a large amount of residue of the surface treatment agent and / or its modified product is present on the glass cloth surface, which does not form a chemical bond with the glass surface and therefore cannot be reduced by water washing. As a result, it is easy to reduce the dielectric loss tangent of the glass cloth. If the ignition loss value is 0.010% by mass or more, it is easy to achieve sufficient adhesion between the matrix resin and the glass cloth, and therefore it is easy to ensure the heat resistance and insulation reliability of the printed wiring board when it is produced.

[0048] <Yarn width / TEX value> The "yarn width / TEX" value, obtained by dividing the width of a glass yarn by the TEX of the glass yarn, is preferably in the range of 10 to 30. This value is preferably in the range of 11 to 29, more preferably in the range of 12 to 28, even more preferably in the range of 13 to 27, and particularly preferably in the range of 14 to 26. Here, the "yarn width / TEX" value corresponds to a parameter representing the convergence of the glass yarn. If the convergence of the warp yarn is insufficient in the warp warping process of a glass cloth, the warp yarn is likely to become frayed, which makes it easy for yarn breakage to occur. Therefore, if the "yarn width / TEX" value is 30 or less, it is easy to ensure the convergence of the glass yarn, and therefore it is easy to prevent breakage of the glass yarn in the warp warping process. If the "yarn width / TEX" value is 10 or more, it is easy to open the glass yarn in the next process, and therefore it is easy to prevent poor impregnation of the matrix resin during prepreg production.

[0049] <Average filament diameter> The average filament diameter of the glass filaments constituting the glass yarn is preferably in the range of 2.5 to 10.0 μm, more preferably in the range of 2.5 to 9.0 μm, even more preferably in the range of 3.5 to 8.5 μm, still more preferably in the range of 3.5 to 8.0 μm, and particularly preferably in the range of 3.5 to 7.5 μm. If the filament diameter is 2.5 μm or more, it is easy to ensure the breaking strength of the filaments, and therefore it is easy to prevent the generation of fluff in the obtained glass cloth. If the filament diameter is 10.0 μm or less, it is easy to avoid an increase in the mass of the glass cloth, and therefore it is easy to transport or process it.

[0050] <Twist Number> The absolute value of the twist number of the glass yarn is preferably in the range of 0.5 to 1.5 turns / 25 mm. More preferably, it is in the range of 0.55 to 1.45 turns / 25 mm, even more preferably, it is in the range of 0.57 to 1.4 turns / 25 mm, still more preferably, it is in the range of 0.59 to 1.3 turns / 25 mm, and particularly preferably, it is in the range of 0.60 to 1.2 turns / 25 mm. By adjusting the twist number of the glass yarn, it is possible to control the Snarl index of the glass yarn. The larger the absolute value of the twist number, the stronger the untwisting force of the glass yarn tends to be, and therefore, the Snarl index tends to be larger. If the absolute value of the twist number of the glass yarn is 0.5 turns / 25 mm or more, it is easy to ensure the bundle property of the glass yarn, and therefore, it is easy to prevent the glass yarn from breaking during the warp setting process and the generation of fluff on the surface of the glass cloth. If the absolute value of the number of twists of the glass yarn is 1.5 times / 25 mm or less, it is easy to prevent the Snarl index of the glass yarn from becoming too large, and in this case, it is easy to avoid the situation where the glass yarn rubs against the bobbin surface when the glass yarn is unwound, causing fluff to form on the surface of the glass cloth.

[0051] The absolute value of the difference in the number of twists between the warp and weft yarns is preferably in the range of 0.01 to 0.70 turns / 25 mm. If the absolute value difference is 0.01 turns / 25 mm or more, the flatness of the glass cloth is easily improved, and the glass yarns are easily opened during the production of the glass cloth. If the absolute value difference exceeds 0.7 turns / 25 mm, the directions of the untwisting forces of the warp and weft yarns are different (e.g., the warp yarns are in the z direction and the weft yarns are in the s direction), and the glass cloth tends to warp significantly. Furthermore, even if the untwisting force direction is the same, if the absolute value difference is large, the difference in untwisting force also tends to be large, and the glass cloth is more likely to warp. Therefore, if the absolute value difference is 0.7 turns / 25 mm or less, the generation of fluff in the obtained glass cloth is easily suppressed. The absolute value of the difference in the number of twists between the warp and weft yarns of the glass cloth is more preferably in the range of 0.05 to 0.65 turns / 25 mm, and even more preferably in the range of 0.07 to 0.55 turns / 25 mm.Furthermore, the absolute value of the difference in the number of twists between the warp and weft yarns of the glass cloth is more preferably in the range of 0.10 to 0.50 turns / 25 mm, and even more preferably in the range of 0.15 to 0.45 turns / 25 mm.

[0052] The twist of the glass yarn is classified as either the z-direction or the s-direction depending on the direction of the twist. In this disclosure, the twist in the z-direction is defined as "positive" and the twist in the s-direction as "negative." For example, in this specification, a "1.00z twist" is expressed as a twist number of 1.00, and a "1.00s twist" is expressed as a twist number of -1.00.

[0053] The twist number of the glass yarn can be adjusted, for example, in the process of twisting the glass yarn (twisting process). In one embodiment, bundling the glass filaments makes it easier to increase the twist number of the glass yarn. Increasing the twist number of the glass yarn makes it easier to suppress the generation of fluff due to breakage of the glass filaments and to suppress yarn breakage during the warping process of the glass cloth. On the other hand, the twist of the glass yarn tends to hinder the glass yarn from expanding in width and tends to cause thickness unevenness of the glass cloth at the twisted portion. Therefore, finding an appropriate twist number and using glass yarn adjusted to such twist number is advantageous in producing a high-quality glass cloth.

[0054] <Glass Yarn Package> In a preferred embodiment, the present disclosure provides a glass yarn package in which glass yarn is wound around a core material. The glass yarn package is a glass yarn package in which the silicon (Si) content in the glass yarn is 0.01% or less than silicon dioxide (SiO ２ ) and the Snarl index of the glass yarn is 400 mm or less. By using such a glass yarn package, it is possible to provide a glass cloth which can improve flatness and also reduce the frequency of fluffing.

[0055] As the preferable requirements for the glass yarn constituting the glass yarn package, the preferable requirements for the glass yarn constituting the glass cloth may be referred to. For example, the glass yarn constituting the glass yarn package may have the ranges described in the following formulas (A), (B), and (C): (A) x + y + z = 100 mass% (B) x ≥ 99.5 mass% (C) 0.0003 ppm ≤ y ≤ 0.50 ppm, where x is silicon dioxide (SiO ２ ) y: silicon content when converted into y, y is the total content of uranium and thorium, z is the total content of elements other than silicon, uranium, and thorium. It is preferable that the absolute value of the number of twists of the glass yarns constituting the glass yarn package is in the range of 0.5 to 1.5 times / 25 mm, and the value of "yarn width / TEX" is in the range of 10 to 30. Note that with regard to the preferred numerical ranges of the glass yarns constituting the glass yarn package, the preferred numerical ranges of the glass yarns constituting the glass cloth may be similarly referred to.

[0056] The core material for winding the glass yarn may be any material that allows the glass yarn to be suitably unwound from the core material, and in one embodiment, is a bobbin. However, the core material is not limited to a bobbin, and may be any material that has a function or configuration equivalent to that of a bobbin.

[0057] <<Methods for Producing Glass Yarn, Glass Yarn Package, and Glass Cloth>> In a preferred embodiment, the present disclosure provides methods for producing glass yarn, glass yarn package, and glass cloth. In one embodiment of the production method, the silicon (Si) content in the glass yarn is 0.01g / g or less than that of silicon dioxide (SiO２ ) is 95.0 to 100 mass % and the Snarl index of the glass yarn is 400 mm or less.

[0058] One aspect of the manufacturing method is a method for manufacturing a glass yarn package, which includes a step of winding the glass yarn around a core material to form a package.

[0059] In addition, one aspect of the manufacturing method is that the silicon (Si) content in the glass fiber is less than that of silicon dioxide (SiO ２ ) in the range of 95.0 to 100 mass %, and the Snarl index of the glass yarn is in the range of 400 mm or less, to obtain a glass cloth.

[0060] One aspect of the manufacturing method is a method for manufacturing a glass cloth, comprising a step of obtaining a glass cloth using a glass yarn, the glass constituting the glass yarn having a bulk dielectric loss tangent at 10 GHz in the range of 0.001 or less and a Snarl index of the glass yarn in the range of 400 mm or less.

[0061] Each of the above-described manufacturing methods in the present disclosure can include a step of manufacturing glass filaments by heating and drawing a glass rod (glass filament manufacturing step), and a step of bundling a plurality of the glass filaments (glass filament bundling step).

[0062] <Glass Rod Manufacturing Process> Known techniques may be used to manufacture a glass rod for producing the glass cloth of the present disclosure. The glass rod may be made of fused silica glass produced by an electric melting method, a flame melting method, or the like, or a synthetic quartz rod produced by a sol-gel method, or the like. In either manufacturing method, it is preferable to perform a purification process on the glass rod, which is the raw material for the glass filament, in order to adjust the silicon content in the glass filament. Furthermore, in order to facilitate control of the Snarl index of the glass filament, it is preferable to perform a purification process on the glass rod so that the total content of uranium and thorium in the glass filament is in the range of 0.0003 to 0.50 ppm. For example, in the case of fused silica glass, it is advantageous to use raw material powder with low uranium and thorium contents. Using a glass rod with a total content of uranium and thorium within the above range facilitates reducing the elongation stress when processing the glass filaments, which in turn facilitates reducing the residual stress in the glass filament and ultimately facilitates lowering the Snarl index of the glass filament.

[0063] <Glass Filament Manufacturing Process> In this process, glass filaments are produced by heating and stretching a glass rod. Known techniques may be used to produce and further process glass filaments. For example, a method of heating and stretching a glass rod is mentioned. In one embodiment, a glass rod having a diameter of 1 to 50 mm is heated and stretched in an electric furnace under an inert atmosphere at a temperature of 2000°C to produce glass filaments having a diameter of 3 to 10 μm. In this case, the diameter of the glass filament can be controlled by adjusting the speed ratio between the feeding speed of the glass rod into the electric furnace and the stretching speed of the glass filament. From the viewpoint of reducing stress during stretching of the glass rod, the temperature during heating and stretching is preferably in the range of 1700 to 2500°C, more preferably in the range of 1800 to 2400°C, and even more preferably in the range of 1900 to 2300°C.

[0064] The inventors have found that stress generated when a glass rod is heated and drawn may remain in the resulting glass yarn, and that the higher this residual stress is, the larger the Snarl index of the glass yarn tends to be. The inventors have also found that, in order to adjust the Snarl index of a glass yarn, it is effective to reduce the residual stress in the glass yarn after drawing the glass yarn, for example, to subject the glass yarn to an annealing treatment. The Snarl index of a glass yarn can be easily reduced by deorienting the microcrystalline structure oriented by drawing through an annealing treatment.

[0065] The annealing treatment is preferably carried out between the step of heating and stretching the glass rod and the step of applying a sizing agent to the glass filament. Furthermore, from the viewpoint of easily reducing the residual stress in the glass filament, the temperature during the annealing treatment is preferably in the range of 1000 to 1900°C, more preferably in the range of 1100 to 1800°C, even more preferably in the range of 1200 to 1700°C, even more preferably in the range of 1300 to 1650°C, and particularly preferably in the range of 1400 to 1600°C. If the temperature during the annealing treatment is 1900°C or less, there is a tendency to easily prevent the glass filament from breaking after heating and stretching. Furthermore, if the temperature during the annealing treatment is 1100°C or higher, the effect of reducing the residual stress in the glass filament is easily obtained. Furthermore, the time during the annealing treatment is preferably in the range of 0.1 to 30 seconds, more preferably in the range of 0.2 to 20 seconds, even more preferably in the range of 0.3 to 5 seconds, and particularly preferably in the range of 0.4 to 3 seconds.

[0066] <Glass filament bundling process> In this process, a plurality of glass filaments are bundled together. Generally, a bundle of glass filaments is called a "strand," so this process can also be understood as a "glass strand manufacturing method." Known techniques may be used to manufacture glass strands.

[0067] When producing a glass strand, it is preferable to apply a sizing agent to the glass filaments in order to enhance the bundling property of the glass filaments and to protect the surfaces of the glass filaments. Known methods for applying the sizing agent include, for example, using a roller-type applicator.

[0068] Known sizing agents include resin-based sizing agents such as PVA, polyurethane, and epoxy resin, as well as starch-based sizing agents. From the viewpoint of the flying property of the glass yarn during the weaving process and the ease of removing the sizing agent from the glass yarn, starch-based sizing agents are preferred. To improve the functionality of the glass yarn, additives such as lubricants and antistatic agents may be added to the sizing agent. From the viewpoint of easily suppressing snarling of the glass yarn, it is preferable to adjust the shape of the yarn path and the heating and drawing furnace, etc., so that tension is applied to each glass filament as uniformly as possible when bundling the glass filaments.

[0069] Since the "thread width / TEX" value, obtained by dividing the width of the glass yarn by the TEX of the glass yarn, is adjusted to a range of 10 to 30, it is possible to adjust the amount of sizing agent attached in the bundling process of the glass filaments. Here, from the viewpoint of easily achieving the effects of the present disclosure, the loss on ignition (LOI) of the glass yarn is preferably in the range of 1.0 to 2.5 mass%, more preferably in the range of 1.1 to 2.4 mass%, even more preferably in the range of 1.2 to 2.3 mass%, and particularly preferably in the range of 1.3 to 2.2 mass%. If the ignition loss of the glass yarn is 1.0 mass% or more, it is easy to ensure the bundling properties of the glass filaments, and in this case, it is easy to adjust the "thread width / TEX" value to a range of 10 to 30. If the ignition loss of the glass yarn is 2.5 mass% or less, it is easy to prevent poor deoiling and insufficient fiber-spreading in the deoiling process and fiber-spreading process of the glass yarn.

[0070] <Twisting Step> The method may include a step of applying a predetermined twist to the glass strand (twisting step). The glass strand can be twisted to a predetermined degree using, for example, a twisting machine. Known devices or techniques may be used for the twisting machine or twisting technique. For example, a method may be used in which a roll of glass strands (e.g., called a "collet") coated with a sizing agent is pulled out, twisted, and wound onto a core material (in one embodiment, a bobbin). At this time, the bobbin is attached to the twisting machine using a fixture called a spindle. The twisting machine generally has a component called a traveler around the spindle, and the number of twists applied to the glass strands can be adjusted by adjusting the speed ratio of the operations of these various components.

[0071] The twisting step may also serve as a step of winding the twisted glass strands around a core material, thereby producing a glass yarn package.

[0072] <Method for Producing Glass Cloth> The method for producing glass cloth includes a step of weaving the above-mentioned glass yarns as warp and weft to obtain glass cloth (weaving step).

[0073] The method for producing a glass cloth may further include a warping step, before the weaving step, of aligning the warp yarns of the glass cloth using glass yarns whose yarn width divided by the TEX of the glass yarns is in the range of 10 to 30, and then applying a sizing agent, and a step of thermally degreasing the glass yarns after the warping step and before, during, or after the weaving step to remove the sizing agent adhering to the glass yarns (thermal degreasing step), a step of applying a surface treatment agent to the glass yarns (surface treatment step), and a step of opening the glass yarns (opening step). By including these steps, it is easy to provide a glass cloth excellent in flatness and fluff quality.

[0074] The above-mentioned glass treatment methods (thermal deoiling process, surface treatment process, and fiber-opening process) can be applied to glass yarns before weaving, and can also be applied to woven glass cloth. In other words, the process of weaving glass yarns to obtain glass cloth may be performed before, during, or after the glass treatment method. Note that "reduction" in the glass treatment method refers to, for example, removing at least a portion of a sizing agent or a silane coupling agent, and some residue may remain. Hereinafter, an embodiment including a warping process, a weaving process, a thermal deoiling process, a surface treatment process, and a fiber-opening process in this order will be described as an example. However, the present disclosure is not limited to the following example.

[0075] <Warping process> In the warping process, the Si content is adjusted to SiO ２Glass yarns having a content of 95.0 to 100% by mass in terms of weight percent can be used, and after the warp yarns are pulled and aligned, a sizing agent (a sizing agent) can be applied to the glass yarns. By providing a sizing agent to the glass yarns, it is easy to suppress the generation of fluff in the glass cloth. As the sizing agent, it is preferable to use one with relatively high sizing ability, such as starch or PVA. In order to apply the sizing agent uniformly to the glass yarns, a preferred method is to immerse the glass yarns in the sizing agent, remove excess sizing agent with a squeeze roller, and then dry the sizing agent.

[0076] <Weaving Process> In the weaving process, a loom can be used to weave the warp yarns prepared in the warping process by beating the weft yarns into the warp yarns. Known looms include air jet, rapier, and shuttle types, but an air jet loom is preferred from the viewpoint of suppressing fluffing of the glass cloth. The absolute value of the number of twists of the glass yarns in the warp warping and weaving processes is preferably in the range of 0.5 to 1.5 turns / 25 mm. Furthermore, in this process, it is preferred to adjust the number of twists of the weft yarn so that the absolute value of the difference in the number of twists between the warp yarns and the weft yarns is in the range of 0.01 to 0.70 turns / 25 mm.

[0077] <Thermal Deoiling Process> In the thermal deoiling process of glass cloth, the glass yarns are heated to reduce, and preferably remove, sizing agents (sizing agents) and their residues, as well as modified products thereof, that are arbitrarily attached to the glass yarns. By performing the thermal deoiling process, it is possible to form a surface treatment layer on the surface of the glass yarns (glass filaments) after reducing organic substances that can increase the dielectric tangent, which makes it easy to produce glass cloth with excellent dielectric properties. Known means (heating means, heating medium, heating mechanism, heating device, heating component, etc.) can be used as the means for thermal deoiling.

[0078] As one embodiment of the thermal deoiling step, for example, a method in which the glass cloth is heated at a temperature of 600 to 1600°C is known.

[0079] In the heat treatment step, by heating a glass cloth greige having a glass yarn softening point of 900°C or higher in a temperature range of 600 to 1600°C, damage to the glass cloth can be easily suppressed and the dielectric loss tangent of the glass cloth can be easily reduced. From the viewpoint of suitably obtaining the effects of the present disclosure, the thermal deoiling temperature is preferably 700 to 1500°C, more preferably 800 to 1400°C, even more preferably 900 to 1300°C, and particularly preferably 1000 to 1200°C. When the thermal deoiling temperature is 600°C or higher, sizing agents and the like adhering to the cloth can be easily removed effectively, making it easy to produce a glass cloth with excellent dielectric properties. When the thermal deoiling temperature is 1600°C or lower, devitrification of the glass can be easily suppressed, and as a result, a decrease in the strength of the glass cloth can be easily prevented.

[0080] The heating time is preferably 30 minutes or less, more preferably 15 minutes or less, even more preferably 5 minutes or less, and particularly preferably 90 seconds or less. Since the heat treatment is performed at a high temperature, a heating time of 30 minutes or less tends to reduce damage to the glass cloth, and in this case, problems such as partial holes being formed in the glass cloth during processing or the glass cloth being cut can be easily avoided. From the viewpoint of effectively removing the sizing agent and the like, the heating time may be, for example, 1 second or more, 5 seconds or more, 10 seconds or more, or 15 seconds or more.

[0081] When the thermal deoiling of the glass cloth is carried out in a closed system, it is preferable to place the glass cloth in a heating furnace from the viewpoint of suitable heating by a heating means. Also, from the viewpoint of efficient storage space and heating range, it is preferable to heat the glass cloth while storing it in a rolled state. Furthermore, from the viewpoint of increasing the efficiency of removing organic substances and shortening the time required for removing organic substances, it is preferable to heat the glass cloth while transporting it in the heating furnace. The transportation of the glass cloth can be carried out, for example, by a combination of an unwinding mechanism and a winding mechanism.

[0082] When the thermal deoiling of the glass cloth is carried out in an open system, it is preferable to heat the glass cloth while transporting it, from the viewpoint of ensuring a heated area. The transportation of the glass cloth can be carried out, for example, by a combination of an unwinding mechanism and a winding mechanism.

[0083] The embodiment of the thermal deoiling step is not limited to the above. Another known embodiment of the thermal deoiling step is, for example, a method in which the material is heated in a vacuum or in a gas having a dew point of 15°C or less under conditions in which the heating amount, expressed as a heating temperature (°C) of 100°C or more x heating time (h), is 450 (°C·h) or more (provided that the maximum heating temperature is 100 to 600°C).

[0084] <Heating Means> Examples of the heating means include a heating furnace, an electric heater, a burner, etc., and among these, a gas single radiant tube burner or an electric heater is preferred. A plurality of different heating means may be combined.

[0085] From the viewpoint of efficiently removing organic substances adhering to the surface of the glass cloth, a continuous system in which the glass cloth is heated while being continuously passed through a heating furnace is preferred over a batch system in which the glass cloth wound around a core is heated at a predetermined atmospheric temperature. A system in which the glass cloth can also be continuously washed using washing water with a low metal ion content, such as reverse osmosis (RO) water or ion-exchanged water, is more preferred.

[0086] Furthermore, from the viewpoint of low running costs, the heating means may be such that the glass cloth is heated by bringing a member (contact member) heated to a predetermined temperature into contact with the glass cloth.

[0087] The contact member is preferably one that can heat the glass cloth at a high temperature. The shape of the contact member is preferably a roll because it allows for easy transport of the glass cloth. Specifically, the contact member is preferably, for example, a roll that can be used in a high-temperature range and heats by an induction heating method, which has relatively little temperature variation in the width direction. When the glass cloth is heated by the contact member, the temperature of the contact member and the surface temperature of the glass cloth are considered to be approximately equal.

[0088] When the glass cloth is continuously heated, in order to remove carbides adhering to the roll, the method using the roll is preferably a method equipped with a mechanism for removing adhering foreign matter, such as a mechanism such as a blade.

[0089] <Means for applying steam> The means for applying the above to the glass cloth (means for applying steam) may be spray, shower diffusion, jet nozzle, etc. Alternatively, the gas discharged from the heating furnace can be reused as high-temperature steam.

[0090] The steam applied to the glass cloth may contain, for example, a volatile solvent, water vapor, or a gas other than water vapor. However, water vapor is preferred from the viewpoint of reducing toxicity to the human body and facilitating decomposition of the sizing agent used in the glass fiber. The temperature of the high-temperature steam may be a temperature at which the surface temperature of the glass cloth is higher than 650°C. In this case, if necessary, a method may be adopted in which the high-temperature steam and heated air can be supplied in any ratio. The temperature of the high-temperature steam may be 400°C or higher, 450°C or higher, 550°C or higher, 600°C or higher, or 650°C or higher.

[0091] <Surface Treatment Step> The surface treatment step can be applied to glass yarns and also to 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 according to the present disclosure.

[0092] The step of applying the surface treatment agent can include at least one of a coating step of applying a silane coupling agent to the glass surface using a treatment solution having a concentration of 0.1 to 0.5% by mass, and a fixing step of fixing the silane coupling agent to the glass surface by heating and drying. This facilitates the surface treatment of the glass in a suitable manner.

[0093] Possible methods for applying the treatment liquid to the glass in the coating step include (a) immersing or passing the glass in a treatment liquid stored in a bath (hereinafter referred to as the "immersion method"), and (b) applying the treatment liquid to the glass using a roll coater, die coater, gravure coater, or the like. When using the immersion method, it is preferable to select the immersion time of the glass in the treatment liquid as 0.5 seconds or more and 1 minute or less. Furthermore, when using the immersion method, the glass can be passed through the treatment liquid 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 the treatment liquid is applied to the glass, the solvent contained in the treatment liquid can be heated and dried using methods such as hot air or electromagnetic waves.

[0094] The concentration of the treatment solution is preferably 0.1 to 0.5% by mass, more preferably 0.1 to 0.45% by mass, and even more preferably 0.1 to 0.4% by mass, which makes it easier to perform the surface treatment of the glass more favorably.

[0095] In the fixing step, the heating and drying temperature is preferably 80° C. or higher, more preferably 90° C. or higher, so that the reaction between the silane coupling agent and the glass is sufficiently carried out, and is preferably 300° C. or lower, more preferably 180° C. or lower, so as to prevent deterioration of the organic functional group of the silane coupling agent.

[0096] The process of reducing the silane coupling agent can include at least one of the following steps: a cleaning step for cleaning off the silane coupling agent that has not formed a chemical bond with the glass surface; a drying step for heating and drying the glass after cleaning; and a finish cleaning step for reducing unnecessary components that have not been completely cleaned off and have not formed a chemical bond with the glass surface. This makes it easier to control the ignition loss value. The process of reducing the silane coupling agent can include, for example, a finish drying step after the finish cleaning step.

[0097] Among these, the finish cleaning step can reduce unnecessary components that are not completely washed away with water in the cleaning step and do not form chemical bonds with the glass surface. In this finish cleaning step, for example, an organic solvent can be used as the cleaning liquid. By including the finish cleaning step, even when using low-dielectric glass as disclosed herein, it becomes easier to adjust the difference between the dielectric tangent and bulk dielectric tangent of the resulting glass cloth within the above-described numerical range. As the organic solvent, a highly hydrophobic organic solvent is preferred, and an organic solvent with a high affinity for the residue and modified product of the silane coupling agent having a hydroxyl group is also preferred. The cleaning method can be an immersion method, a shower spray, or the like, and may be heated or cooled as needed. To prevent the glass dissolved in the cleaning liquid from re-adhering, it is preferable to remove excess solvent from the cleaned glass using a squeeze roller or the like.

[0098] The organic solvent usable as the cleaning liquid in the finish cleaning step may be, for example, the following solvents, which may be used alone or in combination: Examples of highly hydrophobic organic solvents include saturated chain aliphatic hydrocarbons such as n-pentane, i-pentane, n-hexane, i-hexane, n-heptane, i-heptane, n-octane, i-octane, 2,2,4-trimethylpentane (isooctane), n-nonane, i-nonane, n-decane, i-decane, and 2,2,4,6,6-pentamethylheptane (isododecane); saturated cyclic aliphatic hydrocarbons such as cyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, and ethylcyclohexane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, trimethylbenzene, and triethylbenzene; and halogen-containing solvents such as chloroform, dichloromethane, and dichloroethane. Examples of organic solvents that have a high affinity for residues or modified products of silane coupling agents include alcohols such as methanol, ethanol, and butanol; ketones such as acetone and methyl ethyl ketone; ethers such as methyl ethyl ether and diethyl ether; amides such as N,N-dimethylformamide and N,N-dimethylacetamide; and dimethyl sulfoxide. Among these, aromatic hydrocarbons, alcohols, or ketones are preferred, with methanol being more preferred, from the viewpoint of easily and efficiently reducing the silane coupling agent physically adhered to the glass. Therefore, it is preferable to use a cleaning solution in which methanol is the main component (50% by mass or more, or 60% by mass or more of methanol per 100% by mass of the cleaning solution) as the cleaning solution in the finish cleaning step.

[0099] In the finish drying step, the cleaning liquid used in the finish washing step can be reduced. In order to facilitate the reduction of the cleaning liquid by drying, the cleaning liquid used in the finish washing step preferably has a boiling point of 120°C or less. For drying, a method of heat drying or air drying can be adopted. When an organic solvent is used as the cleaning liquid, from the viewpoint of safety, it is preferable to carry out heat drying by hot air drying using low-pressure steam or heat transfer oil as a heat source. The drying temperature is preferably equal to or higher than the boiling point of the cleaning liquid, and is preferably equal to or lower than 180°C from the viewpoint of suppressing deterioration of the silane coupling agent.

[0100] <Opening Process> As a method for opening the glass cloth in the opening process, 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 air permeability to be reduced by reducing the tension applied to the glass cloth. In order to prevent a decrease in the tensile strength of 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 yarns, optimizing the sizing agent and increasing the amount of adhesion. As a method for opening glass cloth composed of glass yarns with high glass hardness, dry ice blasting is preferable.

[0101] The above steps do not necessarily have to be performed as separate steps, and a plurality of steps can be combined into one step. For example, when the cleaning step is performed after the weaving step, the cleaning step can also serve as the fiber-spreading step by using a high-pressure water spray or the like. In many cases, the composition of the glass cloth does not usually change before and after fiber-spreading. Furthermore, the method for producing glass cloth can include any step other than the above steps. For example, a slitting step can be included after the fiber-spreading step. Furthermore, if possible, the order of the above steps can be reversed.

[0102] <Prepreg> The prepreg according to the present disclosure contains the glass cloth and a matrix resin impregnated into the glass cloth, thereby making it possible to provide a prepreg with few voids.

[0103] The matrix resin may be a thermosetting resin or a thermoplastic resin. If possible, both may be used in combination, or other resins may be further included.

[0104] Examples of thermosetting resins include: (a) epoxy resins obtained by reacting and curing a compound having an epoxy group with a compound having at least one group selected from the group consisting of an amino group, a phenol group, an acid anhydride group, a hydrazide group, an isocyanate group, a cyanate group, and a hydroxyl group, which reacts with the epoxy group; (b) radical polymerization curable resins obtained by curing a compound having at least one group selected from the group consisting of an allyl group, a methacryl group, and an acrylic group; (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. In addition, when obtaining (a) an epoxy resin, the compounds can be reacted without a catalyst, or the compounds can be reacted by adding a catalyst having reaction catalytic ability, such as an imidazole compound, a tertiary amine compound, a urea compound, or a phosphorus compound. In addition, when obtaining (b) a radical polymerization type curable resin, a thermal decomposition type catalyst or a photodecomposition type catalyst can be used as a reaction initiator.

[0105] 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, fluororesin, etc. As an insulating material for printed wiring boards for high-speed communication, polyphenylene ether or modified polyphenylene ether, which has high radical reactivity, is preferred.

[0106] When the matrix resin used in a printed wiring board for high-speed communication has a vinyl group or a methacryl group, a silane coupling agent that is relatively highly hydrophobic and has a functional group that participates in a radical reaction, such as a methacryl group, is compatible with the matrix resin.

[0107] As described above, the thermosetting resin and the thermoplastic resin can be used in combination. The prepreg can further contain an inorganic filler. The inorganic filler is preferably used in combination with the thermosetting resin, and examples thereof 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 may be used alone or in combination of two or more.

[0108] <Printed Wiring Board> The printed wiring board according to the present disclosure contains the prepreg, which makes it possible to provide a printed wiring board with excellent insulation reliability.

[0109] <Integrated Circuit and Electronic Device> The present disclosure also provides an integrated circuit and an electronic device including the printed wiring board. The integrated circuit and electronic device obtained using the printed wiring board according to the present disclosure have various excellent properties.

[0110] Examples of embodiments of the present disclosure will be described below with reference to examples and comparative examples. However, the present disclosure is not limited to the following examples. For the examples and comparative examples, various productions, measurements, evaluations, etc. were performed by the following methods. Unless otherwise specified, various productions, measurements, evaluations, etc. were performed at room temperature (25°C) and atmospheric pressure.

[0111] <<Measurement>> <Glass cloth thickness (μm)>> The thickness of the glass cloth was determined in accordance with JIS R 3420, Section 7.10. Specifically, using a micrometer, the spindle was gently rotated to lightly contact the measurement surface of the sample parallel to it. Then, the scale was read after the ratchet made three noises. JIS R 3420, Section 7.10, specifies the general test method for cloth products such as glass cloth.

[0112] <Snarl index (mm) of glass filament> The Snarl index of the glass filament was determined in accordance with 9.17 of JIS L 1095. Specifically, first, the glass filament (sample) was stretched so as to be straight with respect to the gripping distance while applying an initial load described in Method A described in 9.17.1 of JIS L 1095 to the glass filament. ―６ A load of 1000 N / tex was applied. One grip B was moved toward the other grip A at a speed of 0.5 m / min to sag the sample. When snare occurred at the load point, the number on the scale plate at the position of grip B was read. The test was conducted 30 times, and the snare index was calculated by calculating the average value.

[0113] <TEX (g / 1000m) of glass yarn> The TEX of the glass yarn was determined in accordance with JIS R3420-2012. Specifically, a glass yarn sampled to a length of 1000m was subjected to a heat deoiling treatment in a muffle furnace set at 625±20°C for 30 minutes, thereby removing the sizing agent adhering to the glass yarn. At this time, whether the sizing agent was removed was determined by whether the weight loss of the glass yarn before and after heat deoiling was less than 0.1% by mass. In other words, it was determined that the sizing agent was removed when the weight loss of the glass yarn before and after heat deoiling was less than 0.1% by mass. The TEX of the glass yarn was determined by measuring the weight of 1000m of glass yarn after the heat deoiling treatment was completed.

[0114] <Content of Each Element Contained in Glass Fiber> The contents of silicon, uranium, and thorium constituting the glass fiber were determined by an absolute calibration curve method using an ICP mass spectrometer.

[0115] <Silicon Content (% by mass)> In order to reduce impurities (e.g., sizing agents) attached to the glass yarn or its raw material, a constant solution was prepared by the following method: The glass yarn (sample) was weighed, hydrolyzed with sodium hydroxide, and then dissolved in dilute nitric acid to prepare a constant solution.

[0116] The silicon content of the obtained constant solution was measured using an ICP optical emission spectrometer (PS3520VDDII manufactured by Hitachi High-Tech Science Corporation), and then converted into an oxide value to determine the silicon content in the sample.

[0117] <Uranium and Thorium Content (ppm)> A weighed glass fiber (sample) was washed with aqua regia by heating, and then washed with ultrapure water. This sample was decomposed with nitric acid, hydrofluoric acid, and sulfuric acid, and heated and concentrated until white sulfuric acid smoke was generated, and then a constant volume solution was prepared using dilute nitric acid.

[0118] The uranium and thorium contents of the obtained constant volume solution were measured using an ICP mass spectrometer (SPQ9400 manufactured by SII NanoTechnology Inc.) to determine the respective contents of uranium and thorium contained in the sample.

[0119] <Content of Other Components (% by mass)> The content of other components (elements other than silicon, uranium, and thorium) in the glass yarn (sample) was determined by subtracting the content of silicon, uranium, and thorium from 100% by mass. The other components are shown as "impurities" in the table below. Here, the unit "ppm" indicating the content of uranium and thorium was converted as 1 ppm = 0.0001% by mass.

[0120] <Twist Number of Glass Yarns and Its Absolute Value Difference (Twists / 25 mm)> Measurements were performed in accordance with JIS R3420 to obtain the twist number of the glass yarns (twists / 25 mm). When measuring the twist number, glass yarns (warp or weft) were pulled out of the glass cloth so that the twist number of the glass yarns in the glass cloth could be accurately measured, and measurements were performed on the glass yarns (warp or weft). Regarding the obtained values, twist in the z direction was treated as positive, and twist in the s direction was treated as negative. For example, a twist of 1.00z (1.00 (twists / 25 mm) in the z direction) was treated as +1.00, and a twist of 1.00s (1.00 (twists / 25 mm) in the s direction) was treated as -1.00. Then, the absolute difference in the number of twists of the warp and weft yarns (turns / 25 mm) was calculated using the following formula: Absolute difference in number of twists = |number of twists of warp yarns - number of twists of weft yarns|.

[0121] <Glass yarn width (μm)> While transporting the glass yarn at a speed of 1 m / min, an LED projection type transmission dimension measuring instrument (HIGH ACCURACY CMOS MICROMETER LS-9006MR / manufactured by Keyence Corporation) was used to measure the yarn bundle width of the glass yarn over a length of 50 m. From the obtained yarn bundle width data for a length of 50 m, the proportion of yarns with a specific bundle width or less and the average value of the yarn bundle width were calculated. The yarn bundle width measurement using the LED projection type transmission dimension measuring instrument was performed under conditions that allowed for measurement values ​​of 1,934 points per 1 m to be obtained. If an error occurred due to LED out-of-focus or the like (a value of -9999 was displayed), the measurement value was deleted, and the average value of the glass yarn width was calculated. Other measurement values ​​that resulted in errors were appropriately omitted for the calculation. The tension acting on the glass yarn while it was being transported was 0.12 to 0.18 N when measured with a tension meter (Control Instruments ETPB-100-C0585 manufactured by SCHMIDT).

[0122] <Yarn width / TEX (μm / (g / 1000 m))> The yarn width obtained above was divided by the TEX obtained above to find the value of yarn width / TEX.

[0123] <Bulk Dielectric Loss Tangent at 10 GHz> The bulk dielectric loss tangent at 10 GHz of each glass rod (bulk), the raw material for each glass filament, was determined in accordance with IEC 62562. Specifically, glass plate samples of 300 μm or less, sampled to the size required for measurement using a split cylinder resonator, were stored in a constant temperature and humidity oven at 23°C and 50% RH for 8 hours. The dielectric properties of the stored samples were then measured using a split cylinder resonator (manufactured by EM Lab) and an impedance analyzer (manufactured by Agilent Technologies). Measurements were performed five times for each sample, and the average values ​​were calculated. IEC 62562 primarily specifies methods for measuring the dielectric properties of fine ceramic materials used in microwave circuits in the microwave band.

[0124] <Number of filaments and filament diameter (μm) of each warp and weft yarn> In calculating the average spread degree, the number of filaments and filament diameter of each warp and weft yarn 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 filament diameter of the warp yarn (or the weft yarn) were measured in the cross-sectional image. Similarly, image acquisition of the glass yarn and measurement of the number of filaments were repeated, and the average values ​​of the five measured values ​​obtained were used as the number of filaments and filament diameter of the warp yarn (or the weft yarn).

[0125] <Warp Width and Weft Width> For calculating the average degree of opening, the warp width and weft width were determined by the following method. First, five glass cloth samples each measuring 70 mm in the warp direction and 70 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 value of the widths of the 250 warp threads (or weft threads) was determined. The average value thus determined was used as the warp width (or weft width).

[0126] <Openness (%) of warp and weft yarns, and average openness (%) of glass cloth> The openness of the warp yarns of the glass cloth was calculated by the following formula: Openness (%) of warp yarns = [warp width (µm) / {number of warp filaments × warp filament diameter (µm)}] × 100. The openness of the weft yarns of the glass cloth was calculated by the following formula: Openness (%) of weft yarns = [weft width (µm) / {number of weft filaments × weft filament diameter (µm)}] × 100.

[0127] Using the calculated warp openness (%) and weft openness (%), the average openness was calculated according to the following formula: Average openness (%) = {warp openness (%) + weft openness (%)} / 2.

[0128] <Fluff Quality> The glass cloths obtained in the examples and comparative examples were subjected to a roll-to-roll inspection table, and while applying a tension of 100 N / 1000 mm and irradiating with a halogen lamp, the number of fluffs, particularly the number of fluffs with protrusions of 1 mm or more, was visually counted. ２ The number of fluffs per unit area was treated as the fluff frequency, and fluff quality was evaluated using the fluff frequency according to the following criteria: (Measurement criteria) Fluff quality A: The fluff frequency is 10 fluffs / m ２ Fluff quality B: Fluff frequency is 11 to 20 pieces / m ２ Fluff quality C: Fluff frequency is 21 pieces / m ２ That's all.

[0129] <Warpage of Glass Cloth> The glass cloths obtained in the examples and comparative examples were cut into samples measuring 200 mm x 200 mm. The samples were placed on a flat measuring table, and the warpage of the glass cloths was measured.

[0130] 1(a) and 1(b) are schematic diagrams for explaining a method for measuring the amount of warpage of a glass cloth. Fig. 1(a) is a plan view of the glass cloth and the mounting base viewed from above, and Fig. 1(b) is a schematic cross-sectional view of the left end of the glass cloth (the portion surrounded by dotted line A) in Fig. 1(a) when the left end is viewed so that the left end is in the front-rear direction. In Fig. 1(a) and 1(b), the x-direction, y-direction, and z-direction correspond to each other.

[0131] As shown in the figure, a glass cloth sample 2 is placed on a flat measuring table 1. The left end of the sample 2 is curved so as to rise from the measuring table 1, and as a result, the sample 2 is raised by a height T1. In this case, the height T1 is treated as the amount of warpage at the left end of the glass cloth. As in the example shown in Figures 1(a) and 1(b), the height T2 at the upper end of the glass cloth, the height T3 at the right end of the glass cloth, and the height T4 at the lower end of the glass cloth are treated as the amounts of warpage at the upper, right, and lower ends of the glass cloth, respectively. Of the amounts of warpage at the four ends of the glass cloth, the maximum amount of warpage Tmax is represented as "amount of warpage" in the table below.

[0132] Figures 2(a) and 2(b) are schematic diagrams for further explaining the method for measuring the amount of warpage. Figures 2(a) and 2(b) correspond to the cross section of the portion surrounded by dotted line A in Figure 1(a). Of these, Figure 2(a) shows a sample curled at the left end. In this case, the height Ta of the apex of the curl is treated as the amount of warpage at the left end of the glass cloth. Also, Figure 2(b) shows a sample curved in an arched shape at the left end. In this case, the height Tb of the apex of the arch is treated as the amount of warpage at the left end of the glass cloth.

[0133] <Preparation of Prepreg Samples> 45 parts by mass of polyphenylene ether (Noryl SA9000, manufactured by SABIC Corporation), 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 obtained in each of the examples and comparative examples was impregnated with the prepared varnish and then dried at 115°C for 1 minute. This gave a prepreg sample.

[0134] <Malfunction Performance Test> Two sheets of the prepreg obtained above were sandwiched between two sheets of copper foil with a thickness of 18 μm. ２The substrate was fabricated by heating and pressing at 400 K for two hours, thereby hardening it. A copper wiring pattern with a 10 μm L / S (line and space) was then fabricated on the substrate, and 30 DRAMs were mounted (so as to be electrically connected to the wiring pattern). The substrate with the DRAMs mounted on it was continuously operated for 1,000 hours at a temperature of 150°C and a frequency of 10 GHz. Based on this result, the malfunction performance due to the uranium and thorium contained in the glass yarn was evaluated. (Evaluation Criteria) A: 0 DRAM malfunctions. B: 1-2 DRAM malfunctions. C: 3-4 DRAM malfunctions. D: 5-6 DRAM malfunctions. E: 7-8 DRAM malfunctions. F: 9 DRAM malfunctions. G: 10 or more DRAM malfunctions.

[0135] Examples and Comparative Examples Production of Glass Filament 1 and Its Package A glass filament was produced using a quartz glass rod (diameter = 1 mm) with a silicon content of 99.92% by mass and a total uranium and thorium content of 0.103 ppm. The quartz glass rod was fed into a heating furnace filled with a sufficient amount of argon gas and set at 1970 ° C., and heated and drawn to produce a glass filament with a diameter of 5.0 μm and 50 filaments. Each heated and drawn glass filament was passed through a heating furnace set at 1500 ° C. for 1 second to reduce residual stress present in the glass filament (annealing treatment). The annealed glass filaments were aligned and bundled using an applicator to apply a sizing agent containing starch as the main agent, and then wound around a collet to obtain a glass filament bundle (glass strand). The obtained filament bundle was twisted in the z direction at a pitch of 0.8 turns / 25 mm using a twisting machine and wound around a bobbin to obtain glass yarn 1 and a package thereof.

[0136] <Production of Glass Fiber 2 and Its Package> Glass fiber 2 and its package were obtained in the same manner as glass fiber 1, except that a quartz glass rod (diameter = 1 mm) with a silicon content of 99.98 mass% and a total content of uranium and thorium of 0.0036 ppm was used.

[0137] <Production of Glass Fiber 3 and Its Package> Glass fiber 3 and its package were obtained in the same manner as glass fiber 1, except that a quartz glass rod (diameter = 1 mm) with a silicon content of 99.90 mass% and a total content of uranium and thorium of 0.204 ppm was used.

[0138] <Production of Glass Fiber 4 and Its Package> Glass fiber 4 and its package were obtained in the same manner as glass fiber 1, except that a quartz glass rod (diameter = 1 mm) with a silicon content of 99.85 mass% and a total content of uranium and thorium of 0.389 ppm was used.

[0139] <Production of Glass Yarn 5 and Package Thereof> Glass yarn 5 and its package were obtained in the same manner as in Example 1, except that a glass rod was heated and drawn so that the number of filaments was 200.

[0140] <Production of Glass Yarn 6 and Package Thereof> Glass yarn 6 and its package were obtained in the same manner as in Example 2, except that the glass rod was heated and drawn so that the number of filaments was 200.

[0141] <Production of Glass Yarn 7 and Package Thereof> The glass yarn 7 and its package were obtained in the same manner as in Example 1, except that the glass yarn 7 was twisted in the z direction at a pitch of 0.4 turns / 25 mm.

[0142] <Production of Glass Yarn 8 and Package Thereof> A glass yarn 8 and a package thereof were obtained in the same manner as in Example 1, except that the temperature for annealing the glass filaments was 1200°C.

[0143] <Production of Glass Yarn 9 and Package Thereof> A glass yarn 9 and a package thereof were obtained in the same manner as in Example 2, except that the temperature for annealing the glass filaments was 1200°C.

[0144] <Production of Glass Yarn 10 and Package Thereof> The glass yarn 10 and its package were obtained in the same manner as in Example 1, except that the glass filaments were not annealed.

[0145] <Production of Glass Fiber 11 and Its Package> Glass fiber 11 and its package were obtained in the same manner as glass fiber 1, except that a quartz glass rod (diameter = 1 mm) with a silicon content of 99.70 mass% and a total content of uranium and thorium of 0.561 ppm was used.

[0146] <Production of Glass Yarn 12> Glass was processed in the same manner as in Example 1, except that the temperature for annealing the glass filaments was set to 2000° C. However, several glass filaments were broken during the annealing treatment, and therefore, the glass yarn and its package could not be obtained.

[0147] <Production of Glass Fiber 13 and Its Package> Glass fiber 13 and its package were obtained in the same manner as glass fiber 1, except that a quartz glass rod (diameter = 1 mm) with a silicon content of 99.99 mass% and a total content of uranium and thorium of 0.0017 ppm was used.

[0148] <Production of Glass Fiber 14 and Its Package> Glass fiber 14 and its package were obtained in the same manner as glass fiber 1, except that a quartz glass rod (diameter = 1 mm) with a silicon content of 99.91 mass% and a total content of uranium and thorium of 0.09 ppm was used.

[0149] <Production of Glass Fiber 15 and Its Package> Glass fiber 15 and its package were obtained in the same manner as glass fiber 1, except that a quartz glass rod (diameter = 1 mm) with a silicon content of 99.99 mass% and a total content of uranium and thorium of 0.0006 ppm was used.

[0150] <Production of Glass Fiber 16 and Its Package> Glass fiber 16 and its package were obtained in the same manner as glass fiber 1, except that a quartz glass rod (diameter = 1 mm) with a silicon content of 99.99 mass% and a total content of uranium and thorium of 0.0010 ppm was used.

[0151] <Production of Glass Fiber 17 and Its Package> Glass fiber 17 and its package were obtained in the same manner as glass fiber 1, except that a quartz glass rod (diameter = 1 mm) with a silicon content of 99.98 mass% and a total content of uranium and thorium of 0.0022 ppm was used.

[0152] <Production of Glass Fiber 18 and Its Package> Glass fiber 18 and its package were obtained in the same manner as glass fiber 1, except that a quartz glass rod (diameter = 1 mm) with a silicon content of 99.93 mass% and a total content of uranium and thorium of 0.03 ppm was used.

[0153] Example 1: Glass yarn 1 was used as the warp and weft yarns. In the warp warping process, the warp yarns were aligned at a line speed of 60 m / min, and a loom beam was produced that underwent secondary sizing using a PVA sizing agent. Then, using an air jet loom, 2000 m of plain weave glass cloth was woven with a weave density of 66 warp yarns / 25 mm and 68 weft yarns / 25 mm and a cloth width of 1300 mm. During the weaving process, the number of weft twists can be adjusted by changing the loom conditions. Therefore, the main nozzle pressure and sub-nozzle angle of the loom were adjusted so that the number of weft twists in the z direction was 0.6 twists / 25 mm.

[0154] The resulting glass cloth was washed with ion-exchanged water and then dried. This removed alkali metal ions and other substances adhering to the cloth surface. The cloth was then heated at 1000°C for 15 seconds to deoil (thermal deoiling process). Subsequently, a treatment solution was prepared by dispersing 0.3% by mass of 3-methacryloxypropyltrimethoxysilane (silane coupling agent A); Z6030 (manufactured by Dow-Toray Industries, Inc.) in pure water adjusted to a pH of 3 with acetic acid. The cloth was immersed in the treatment solution at a line tension of 100 N and a line speed of 15 m / min (surface treatment process). After squeezing the treatment solution out of the cloth, it was heated at 130°C for 60 seconds and dried, thereby fixing the silane coupling agent (fixing process).

[0155] The dried cloth was then immersed in water at a frequency of 25 kHz and an output of 0.50 W / cm ２ The cloth was then subjected to an opening treatment using a columnar flow of water ejected from a high-pressure water spray at 1.4 MPa, while reducing excess silane coupling agent physically attached to the cloth (opening step). The cloth was then dried at 130°C for 1 minute (drying step). As a result of the above, the glass cloth of Example 1 was obtained.

[0156] Examples 2 to 16 and Comparative Example 1 Glass cloths were obtained in the same manner as in Example 1, except that the items shown in the table below were changed as shown in the table below.

[0157] The manufacturing conditions and evaluation results for the Examples and Comparative Examples are shown in the table below. Note that prepregs, printed wiring boards, integrated circuits, and electronic devices could be manufactured by ordinary methods using the glass cloths of the Examples.

[0158]

[0159]

[0160]

[0161]

[0162]

[0163]

[0164] From the above table, it was confirmed that the examples can provide a glass cloth that can improve flatness and also reduce the frequency of fluffing. Furthermore, from the above table, it was also confirmed that suitably controlling the total content of uranium and thorium in the glass yarn is advantageous for evaluation in the malfunction performance test.

[0165] The present disclosure can be suitably used in fields relating to glass yarn, glass cloth, prepreg, printed wiring boards, and methods for manufacturing glass cloth.

[0166] 1: Measuring table 2: Glass cloth sample

Claims

1. A glass cloth made of glass yarn, wherein the silicon (Si) content in the glass yarn is silicon dioxide (SiO ２ ) is 95.0 to 100 mass % in terms of the total mass of the glass fibers, and the Snarl index of the glass fibers is 400 mm or less.

2. A glass cloth made of glass yarns, wherein the bulk dielectric loss tangent at 10 GHz of the glass constituting the glass yarns is in the range of 0.001 or less, and the Snarl index of the glass yarns is 400 mm or less.

3. The glass cloth according to claim 1 or 2, wherein the Snarl index of the glass yarn is 70 mm or more.

4. The glass fibers are within the ranges defined by the following formulas (A), (B), and (C): (A) x + y + z = 100 mass% (B) x ≥ 99.5 mass% (C) 0.0003 ppm ≤ y ≤ 0.50 ppm, where x is silicon dioxide (SiO ２ 3. The glass cloth according to claim 1, comprising glass yarns satisfying the following formula: y: silicon content when converted into y: total content of uranium and thorium; and z: total content of elements other than silicon, uranium, and thorium.

5. The glass cloth according to claim 4, wherein the range of x is 99.6 mass % or more.

6. The glass cloth according to claim 4, wherein the range of x is 99.9 mass % or more.

7. The glass cloth according to claim 1 or 2, wherein the glass yarn is treated with a surface treatment agent containing a silane coupling agent.

8. The surface treatment agent is represented by the following formula (1): X(R) 3-n SiY n ...(1) (in formula (1), X represents an organic functional group having at least one of an amino group and an unsaturated double bond group having radical reactivity, each Y is independently an alkoxy group, n represents an integer of 1 or more and 3 or less, and each R is independently a group selected from the group consisting of a methyl group, an ethyl group, and a phenyl group).

9. The glass cloth according to claim 8, wherein X in the formula (1) is an organic functional group that does not form a salt with an ionic compound.

10. The glass cloth according to claim 8, wherein X in the formula (1) does not include an amine and / or an ammonium cation.

11. The glass cloth according to claim 8, wherein X in the formula (1) is an organic functional group having a methacryloxy group and / or an acryloxy group.

12. The glass cloth according to claim 1 or 2, wherein the absolute value of the number of twists of the glass yarns is in the range of 0.5 to 1.5 twists / 25 mm.

13. The glass cloth according to claim 1 or 2, wherein the glass cloth has the glass yarns as warp and weft, and the absolute value of the difference in the number of twists between the warp and weft is in the range of 0.01 to 0.70 turns / 25 mm.

14. The glass cloth according to claim 1 or 2, wherein the thickness of the glass cloth is 60 μm or less.

15. The glass cloth according to claim 1 or 2, which is for use in printed wiring boards.

16. A prepreg comprising the glass cloth according to claim 1 or 2 and a thermosetting resin.

17. A printed wiring board comprising the prepreg of claim 16.

18. An integrated circuit comprising the printed wiring board of claim 17.

19. An electronic device comprising the printed wiring board according to claim 17.

20. A method for manufacturing glass cloth, wherein the silicon (Si) content in the glass yarn is less than that of silicon dioxide (SiO ２ ) in the range of 95.0 to 100 mass % in terms of the total mass of the glass fiber, and the Snarl index of the glass fiber is 400 mm or less, to obtain a glass cloth.

21. A method for producing glass cloth, comprising a step of obtaining glass cloth using glass yarns, the bulk dielectric loss tangent of which at 10 GHz is in the range of 0.001 or less, and the Snarl index of the glass yarns is 400 mm or less.

22. The method for producing glass cloth according to claim 20 or 21, wherein the Snarl index of the glass yarn is 70 mm or more.

23. The glass yarn has a content within the ranges defined by the following formulas (A), (B), and (C): (A) x + y + z = 100 mass% (B) x ≥ 99.5 mass% (C) 0.0003 ppm ≤ y ≤ 0.50 ppm, where x is silicon dioxide (SiO ２ y: silicon content when converted into uranium and thorium; z: total content of elements other than silicon, uranium, and thorium, to obtain a glass cloth using the glass yarn satisfying the following formula: y: silicon content when converted into uranium and thorium; z: total content of elements other than silicon, uranium, and thorium.

24. A method for producing glass cloth according to claim 20 or 21, comprising: a step of warping the glass yarns used as warp yarns (warp warping step); and a step of weaving using the glass yarns (weaving step), wherein the absolute value of the number of twists of the glass yarns is adjusted to a range of 0.5 to 1.5 turns / 25 mm in the warp warping step and / or the weaving step.

25. A method for producing a glass cloth according to claim 24, wherein the glass cloth has the glass yarns as warp and weft, and the method includes a step of adjusting the number of twists of the weft so that the absolute value of the difference in the number of twists between the warp and weft is in the range of 0.01 to 0.70 turns / 25 mm.

26. A method for producing a glass cloth according to claim 24 or 25, wherein the warp warping step and / or the weaving step are carried out using glass yarns whose width divided by TEX is in the range of 10 to 30.

27. A glass yarn package having a core material and a glass yarn wound around the core material, wherein the silicon (Si) content in the glass yarn is silicon dioxide (SiO ２ ) is 95.0 to 100 mass% in terms of the total mass of the glass yarn, and the Snarl index of the glass yarn is 400 mm or less.

28. The glass yarn package according to claim 27, wherein the glass yarn has a Snarl index of 70 mm or more.

29. The glass yarn has a composition represented by the following formulas (A), (B), and (C): (A) x + y + z = 100 mass% (B) x ≥ 99.5 mass% (C) 0.0003 ppm ≤ y ≤ 0.50 ppm, where x is silicon dioxide (SiO ２ ) y: silicon content when converted into y, y: total content of uranium and thorium, and z: total content of elements other than silicon, uranium, and thorium. The glass filament package according to claim 27 or 28, 30. A glass yarn package according to claim 27 or 28, wherein the absolute value of the number of twists of the glass yarn is in the range of 0.5 to 1.5 twists / 25 mm.

31. The glass yarn package according to claim 27 or 28, wherein the value obtained by dividing the yarn width of the glass yarn by the TEX is in the range of 10 to 30.

32. Glass yarn used for weaving glass cloth, wherein the silicon (Si) content in the glass yarn is silicon dioxide (SiO ２ ) is 95.0 to 100 mass% in terms of the total mass of the glass fiber, and the Snarl index of the glass fiber is 400 mm or less.

33. The glass thread according to claim 32, wherein the Snarl index of the glass thread is 70 mm or more.

34. The glass yarn has a content within the ranges defined by the following formulas (A), (B), and (C): (A) x + y + z = 100 mass% (B) x ≥ 99.5 mass% (C) 0.0003 ppm ≤ y ≤ 0.50 ppm, where x is silicon dioxide (SiO ２ ) y: silicon content when converted into uranium and thorium; z: total content of elements other than silicon, uranium, and thorium. The glass filament according to claim 32 or 33, wherein: y: silicon content when converted into uranium and thorium; z: total content of elements other than silicon, uranium, and thorium.

35. The glass thread according to claim 34, wherein y, which represents the total content of uranium and thorium, is in the range of 0.0003 to 0.0010 ppm.

36. The glass thread according to claim 34, wherein y, which represents the total content of uranium and thorium, is in the range of more than 0.0010 and not more than 0.0015 ppm.

37. The glass thread according to claim 34, wherein y, representing the total content of uranium and thorium, is in the range of more than 0.0015 and not more than 0.0018 ppm.

38. The glass thread according to claim 34, wherein y, representing the total content of uranium and thorium, is in the range of more than 0.0018 and not more than 0.0035 ppm.

39. The glass thread according to claim 34, wherein y, representing the total content of uranium and thorium, is in the range of more than 0.0035 and not more than 0.0040 ppm.

40. The glass thread according to claim 34, wherein y, representing the total content of uranium and thorium, is in the range of more than 0.0040 and not more than 0.09 ppm.

41. The glass thread according to claim 34, wherein y, representing the total content of uranium and thorium, is in the range of more than 0.09 and not more than 0.12 ppm.

42. The glass thread according to claim 34, wherein y, representing the total content of uranium and thorium, is in the range of more than 0.12 and not more than 0.50 ppm.

43. The glass thread according to claim 32 or 33, wherein the Snarl index of the glass thread is in the range of 330 to 400 mm.

44. The glass thread according to claim 32 or 33, wherein the Snarl index of the glass thread is in the range of 300 to 329 mm.

45. The glass thread according to claim 32 or 33, wherein the Snarl index of the glass thread is in the range of 220 to 299 mm.

46. ​​The glass thread according to claim 32 or 33, wherein the Snarl index of the glass thread is in the range of 200 to 219 mm.

47. The glass thread according to claim 32 or 33, wherein the Snarl index of the glass thread is in the range of 125 to 199 mm.

48. The glass thread according to claim 32 or 33, wherein the Snarl index of the glass thread is in the range of 110 to 124 mm.

49. The glass thread according to claim 32 or 33, wherein the Snarl index of the glass thread is 110 mm or less.

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