Glass cloth

Abstract

The purpose of the present invention is to provide a glass cloth in which a residual curvature 2HB / B, which is the ratio of the weft-direction curve hysteresis 2HB to the weft-direction bending stress B, is 0.5 (cm-1) or less, and the residual shear distortion 2HG / G, which is the ratio of the weft-direction shear hysteresis 2HG (gf / cm) to the weft-direction shear stress G (gf / cm / deg), is 1.4 (deg -1) or less.　Provided is a glass cloth in which glass yarn composed of a plurality of long glass fibers is configured as warp and weft, wherein at least a part of the surface of the long glass fibers includes (A) a polyoxyalkylene bisphenol A ether and (B) a silane coupling agent having an acrylic group or a methacrylic group, the warp density and weft density of the glass cloth are each at least 70 per 25 mm, and the amount of carbon in the glass cloth is 0.4-1.5 mass%.

Description

[Technical Field]

[0001] This invention relates to glass cloth and prepregs. [Background technology]

[0002] Laminated boards such as printed circuit boards comprise an insulating layer and a conductive layer formed on top of it. Typically, glass fiber reinforced resin, strengthened with a glass fiber substrate such as glass cloth, is used as the insulating layer.

[0003] In recent years, there has been a growing demand for smaller and more powerful electronic components, and even greater miniaturization is required for laminated boards. To meet these demands, thin printed circuit boards and multilayer printed circuit boards have been developed, and thin glass cloth has been developed as the glass fiber used in them.

[0004] For example, Patent Document 1 describes a glass cloth that can suppress the occurrence of pinholes in a prepreg using glass cloth even when the average number of rows is less than 3.00, and can maintain the excellent appearance quality of the prepreg by having less fuzzing of the glass cloth. Specifically, Patent Document 1 describes the glass cloth as being composed of warp and weft threads made of 14 to 55 glass filaments with a diameter in the range of 3.0 to 4.2 μm, with a weave density of 86 to 140 threads / 25 mm, a thickness in the range of 7.5 to 12.0 μm, and 1 m 2A glass cloth having a mass in the range of 6.0 to 10.0 g per unit, wherein the average number of rows, expressed as the value obtained by dividing the thickness of the glass cloth by the average value of the diameter of the warp glass filaments and the diameter of the weft glass filaments (thickness of glass cloth / {(diameter of warp glass filaments + diameter of weft glass filaments) / 2}), is in the range of 2.00 or more and less than 3.00, wherein the opening degree of the warp threads (width of warp threads / (diameter of glass filaments constituting the warp threads × constituting the warp threads) The following glass cloth is described, in which the average fiber opening degree, expressed as the geometric mean ((fiber opening degree of warp threads × fiber opening degree of weft threads) 1 / 2) of the fiber opening degree of the weft (width of the weft thread / (diameter of the fiber opening degree of the weft threads × number of fiber opening degrees of the weft threads)) is in the range of 1.000 to 1.300, and the fiber width ratio, expressed as the ratio of the width of the warp threads to the width of the weft threads (width of warp threads / width of weft threads), is in the range of 0.720 to 0.960.

[0005] On the other hand, the glass cloth is surface-treated with a silane coupling agent to improve the impregnation and adhesion of the matrix resin in the prepreg and printed circuit board obtained from the prepreg to the glass cloth. As the surface-treated glass cloth, a surface-treated glass fiber fabric is known, which comprises a glass fiber fabric and a treatment agent attached to the glass fiber fabric, wherein the treatment agent contains a silane compound and a water-soluble polyurethane (see, for example, Patent Document 2). It is said that this surface-treated glass fiber fabric makes it possible to provide a surface-treated glass fiber fabric and a method for manufacturing the same that exhibits less mesh slippage even when thinned and has sufficient rigidity. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2018-21274 [Patent Document 2] Japanese Patent Publication No. 2006-342445 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] In recent years, in order to meet the demands for miniaturization of electronic devices and the demands for high-performance printed circuit boards, the thinning of prepregs and printed circuit boards has progressed further. Thinning of prepregs and printed circuit boards requires glass cloth with a thin profile. Furthermore, due to the rapidly increasing demand for high-speed transmission and processing of large amounts of data, there is a need for glass fibers with a low dielectric constant to be used in prepregs and printed circuit boards.

[0008] To form a thin glass cloth, it is necessary to weave it using warp and weft threads made of glass fibers with a smaller fiber diameter, and then flatten the warp and weft threads through a fiber-opening process.

[0009] In order to reduce the dielectric constant of glass fibers, low-dielectric-constant glass (for example, NE glass, L glass, LU glass manufactured by Unitika Ltd., etc.) is used as the glass material constituting the glass fibers.

[0010] Thin glass cloths, or glass cloths made with low dielectric constant glass, have the problem of lower tensile strength and being more prone to breakage compared to glass cloths made with relatively thick, general-purpose E-glass.

[0011] Here, the glass cloth used in the prepreg and printed circuit board is surface-treated with a surface treatment agent containing a silane coupling agent. This surface treatment process is carried out in the final stage of the glass cloth manufacturing process. The surface treatment is performed by impregnating glass cloth, which is continuous in the warp direction, with a surface treatment agent containing a silane coupling agent, adjusting the amount of surface treatment agent applied with a nip roll, and then drying it. The dried glass cloth is wound up to form a glass cloth roll, and this glass cloth roll is then wound back up and impregnated with a matrix resin to form a prepreg.

[0012] Furthermore, the inventors investigated and found that when manufacturing glass cloth with relatively low tensile strength, such as thin glass cloth or glass cloth using low dielectric constant glass, using the technologies of Patent Documents 1 and 2, if the warp tension applied to the glass cloth in the final surface treatment process is kept relatively low in order to prevent breakage of the glass cloth, a problem arises in that warp streaks (streaks extending in the length direction of the warp threads of the glass cloth) tend to occur in the wound glass cloth. Specifically, they found that by lowering the warp tension, bending and waviness occur in the weft direction (width direction) of the glass cloth during the surface treatment process, and if the glass cloth passes through the nip roll with this bending and waviness, it folds and overlaps in the width direction, which causes warp streaks to occur. If warp streaks occur in the final surface treatment process, these warp streaks may be carried over to the prepreg manufacturing process, potentially affecting the quality of the prepreg.

[0013] Furthermore, the inventors have found that when manufacturing glass cloth with relatively low tensile strength, such as thin glass cloth or glass cloth using low dielectric constant glass, using the technologies of Patent Documents 1 and 2, some skewing (a state in which the weft threads are not perpendicular to the warp threads) occurs in the glass cloth during winding. Stress concentrates in the skewing portion, and diagonal wrinkles (wrinkles extending in a direction non-parallel to the length direction of both the warp and weft threads) may occur during winding. This phenomenon does not usually occur in the case of relatively thick glass cloth using, for example, E-glass material. If diagonal wrinkles occur during winding in the final surface treatment process, these diagonal wrinkles may be carried over to the prepreg manufacturing process, potentially affecting the quality of the prepreg.

[0014] Further investigation by the inventors revealed that in order to suppress the aforementioned warp streaks, the "residual curvature 2HB / B, which is the ratio of the bending hysteresis 2HB in the weft direction to the bending stress B in the weft direction," obtained by using a pure bending tester, a type of texture measuring instrument, under the conditions described below, should be set to 0.5 (cm -1It was found that it is important to keep the residual curvature 2HB / B below 0.5 (cm²). The residual curvature 2HB / B is calculated from the bending hysteresis (2HB) and bending stiffness (B) obtained from the hysteresis curve of the bending characteristics measured by a pure bending test machine, and captures the energy loss in the recovery deformation process from bending deformation as residual strain, and quantifies the restoring force with the value of 2HB / B. In other words, the residual curvature 2HB / B can be considered as residual strain in the recovery deformation process from bending deformation, and the smaller this residual strain, the higher the restoring force. The inventors have found that the residual curvature 2HB / B should be 0.5 (cm²). -1 We found that by doing the following, bending and warping are less likely to occur during the glass cloth manufacturing process, and the occurrence of vertical streaks when passing through the nip roll during the process can be easily prevented.

[0015] Furthermore, the inventors have found that in order to suppress the aforementioned diagonal wrinkles, the "residual shear strain rate 2HG / G, which is the ratio of the shear hysteresis 2HG (gf / cm) in the weft direction to the shear stress G (gf / cm / deg) in the weft direction," obtained by using a tensile shear tester, a type of texture measuring instrument, under the conditions described below, should be 1.4 (deg -1 It has been found that it is important to keep the residual shear strain rate below 1.4 (deg). The residual shear strain rate 2HG / G is calculated from the shear hysteresis (2HG) and shear stress (G) obtained from the hysteresis curve of the shear characteristics measured by a tensile shear testing machine. It captures the energy loss in the recovery deformation process from shear deformation as residual strain, and quantifies the restoring force with the value of 2HG / G. In other words, this value can be considered as residual strain in the recovery deformation process from shear deformation, and the smaller the residual strain, the higher the restoring force. The inventors have found that the residual shear strain rate should be 1.4 (deg -1 We found that by doing the following, the inherent distortion in the glass cloth is more easily alleviated during the surface treatment process, and the occurrence of diagonal wrinkles during winding is more easily prevented.

[0016] Therefore, the present invention solves the above problem and makes the residual curvature 2HB / B, which is the ratio of the bending hysteresis 2HB in the weft direction to the bending stress B in the weft direction, 0.5 (cm -1 ) or less, and the residual shear strain rate 2HG / G, which is the ratio of the shear hysteresis 2HG (gf / cm) in the weft direction to the shear stress G (gf / cm / deg) in the weft direction, is 1.4 (deg -1 The main objective of this invention is to provide glass cloth that meets the following criteria. Another objective of this invention is to provide glass cloth in which the occurrence of vertical streaks and diagonal wrinkles is suppressed. [Means for solving the problem]

[0017] The inventors investigated the above problem. To reduce the residual curvature 2HB / B, it is necessary to increase the bending stiffness B while reducing the bending hysteresis 2HB in the weft direction. They found that in order to reduce the bending hysteresis 2HB in the weft direction of the glass cloth, it is important to apply a surface treatment agent to the glass cloth in the surface treatment process that includes (A) polyoxyalkylene bisphenol A ether and (B) a silane coupling agent having an acrylic group or a methacrylic group. Furthermore, they found that increasing the amount of surface treatment agent applied is effective in increasing the bending stiffness B.

[0018] Furthermore, in order to reduce the residual shear strain in the weft direction, it is necessary to increase the shear stress G in the weft direction while reducing the shear hysteresis 2HG in the weft direction. To reduce the shear hysteresis 2HG in the weft direction of the glass cloth, it was found that it is important to apply a surface treatment agent containing (A) polyoxyalkylene bisphenol A ether and (B) a silane coupling agent having an acrylic group or a methacrylic group to the glass cloth during the surface treatment process. In addition, it was found that in order to increase the shear stress G in the weft direction, it is important to set the warp density and weft density of the glass cloth to a certain value or higher, thereby increasing the frictional force associated with the movement of entanglement points due to shear deformation.

[0019] Then, the inventors of the present invention added (A) polyoxyalkylene bisphenol A ether and (B) a silane coupling agent having an acrylic group or a methacrylic group to at least a part of the surface of glass long fibers in a glass cloth composed of a plurality of glass yarns as warp and weft yarns, set the warp density and weft density of the glass cloth to 70 yarns / 25 mm or more, and set the carbon content of the glass cloth to 0.4 to 1.5% by mass, whereby the residual curvature 2HB / B is 0.5 (cm -1 ) or less, and the residual shear strain rate 2HG / G is 1.4 (deg -1 ) or less, and it was found that the occurrence of warp streaks and diagonal wrinkles can be suppressed.

[0020] The present invention has been completed by intensive studies based on such findings.

[0021] That is, the present invention provides an invention in the following aspects. Item 1. A glass cloth composed of a plurality of glass yarns as warp and weft yarns, including (A) polyoxyalkylene bisphenol A ether and (B) a silane coupling agent having an acrylic group or a methacrylic group on at least a part of the surface of the glass long fibers, where the warp density and weft density of the glass cloth are 70 yarns / 25 mm or more, and the carbon content of the glass cloth is 0.4 to 1.5% by mass. Item 2. The glass cloth according to Item 1, wherein the tensile strength in the warp direction is 20 to 120 N / 25 mm. Item 3. The glass cloth according to Item 1 or 2, having a thickness of 5 to 30 μm. Item 4. A roll-shaped long glass cloth in which the glass cloth according to any one of Items 1 to 3 is wound around a core. Item 5. A prepreg containing the glass cloth according to any one of Items 1 to 4 and a thermosetting resin contained in a state of being impregnated in the glass cloth.

Effects of the Invention

[0022] According to the glass cloth of the present invention, by performing surface treatment with a specific surface treatment agent and setting the weave density and carbon content of the glass cloth within a specific range, the residual curvature 2HB / B is 0.5 (cm -1 ) or less and the residual shear strain rate 2HG / G is 1.4 (deg -1 ) The following conditions can be met, and the occurrence of vertical creases and diagonal wrinkles can be effectively suppressed. [Brief explanation of the drawing]

[0023] [Figure 1] (a) shows a schematic diagram of measuring the residual curvature 2HB / B using a pure bending tester, and (b) shows an example of a bending hysteresis curve obtained using a pure bending tester. [Figure 2] (a) shows a schematic diagram of measuring the residual shear strain rate 2HG / G using a tensile shear testing machine, and (b) shows an example of a shear hysteresis curve obtained using a tensile shear testing machine. [Modes for carrying out the invention]

[0024] 1. Glass cloth The glass cloth of the present invention is a glass cloth composed of glass yarn made of a plurality of glass filaments as warp and weft threads, wherein at least a portion of the surface of the glass filaments contains (A) polyoxyalkylene bisphenol A ether and (B) a silane coupling agent having an acrylic group or a methacrylic group, the weaving density of the glass cloth is 70 threads / 25 mm or more, and the carbon content of the glass cloth is 0.4 to 1.5% by mass. The glass cloth of the present invention will be described in detail below.

[0025] [Glass threads that make up glass cloth] The glass cloth of the present invention uses glass yarn, which consists of multiple glass filaments, as the warp and weft threads.

[0026] In the glass cloth of the present invention, the glass material constituting the glass long fibers is not particularly limited. Examples include E glass, T glass, S glass, UT glass, D glass, NE glass, L glass, LU glass, C glass, or AR glass, which are trade names of Unitika Ltd.

[0027] From the standpoint of versatility, it is preferable to use glass fibers having an E-glass composition. The E-glass composition is a composition that, based on the total amount of glass fibers, contains SiO2 in the range of 52 to 56 mass%, B2O3 in the range of 5 to 10 mass%, Al2O3 in the range of 12 to 16 mass%, CaO and MgO in total in the range of 20 to 25 mass%, and Li2O, K2O and Na2O in total in the range of 0 to 1 mass%.

[0028] Furthermore, from the viewpoint of further increasing the strength of the prepreg and printed circuit board, it is preferable that the glass yarn is made of a glass material having a composition containing SiO2 in the range of 60 to 66 mass%, Al2O3 in the range of 20 to 26 mass%, and MgO in the range of 10 to 15 mass%, relative to the total amount of glass fibers.

[0029] Furthermore, from the viewpoint of reducing the dielectric constant and dielectric loss tangent of the prepreg and printed circuit board, it is preferable that the glass yarn is made of a glass material containing SiO2 in the range of 45 to 60 mass%, B2O3 in the range of 15 to 35 mass%, Al2O3 in the range of 10 to 20 mass%, and CaO in the range of 1 to 15 mass%, relative to the total amount of glass fibers, and more preferably made of a glass material containing SiO2 in the range of 45 to 55 mass%, B2O3 in the range of 20 to 35 mass%, Al2O3 in the range of 10 to 20 mass%, and CaO in the range of 3 to 10 mass%, relative to the total amount of glass fibers.

[0030] In this invention, the glass composition is measured by ICP emission spectrometry. Specifically, the Si content and B content are obtained by dissolving a weighed glass cloth sample in sodium carbonate, then dissolving it in dilute nitric acid to a fixed volume, and measuring the resulting sample by ICP emission spectrometry. The Fe content is obtained by dissolving a weighed glass cloth sample in an alkaline solution to a fixed volume, and measuring the resulting sample by ICP emission spectrometry. Furthermore, the Al content, Ca content, and Mg content are obtained by thermally decomposing a weighed glass cloth sample with sulfuric acid, nitric acid, and hydrogen fluoride, then dissolving it in dilute nitric acid to a fixed volume, and measuring the resulting sample by ICP emission spectrometry. A Thermo Fisher iCAP6300Duo can be used as the ICP emission spectrometer.

[0031] In the glass cloth of the present invention, the average fiber diameter of the glass fibers is not particularly limited. For example, the average fiber diameter of the glass fibers can be 2 to 7 μm, and from the viewpoint of making it easier to achieve the effects of the present invention, 2.5 to 5.5 μm is preferred, and 3 to 5 μm is more preferred.

[0032] Furthermore, in the glass cloth of the present invention, there are no particular limitations on the number of glass filaments that constitute the glass yarn. For example, 20 to 200 fibers are possible, and from the viewpoint of making it easier to achieve the effects of the present invention, 20 to 100 fibers are preferred, and 20 to 50 fibers or 30 to 50 fibers are more preferred.

[0033] The average fiber diameter and number of glass fibers are measured and calculated as follows: Two 30cm square pieces of the glass cloth to be measured are prepared. One is used for warp observation and the other for weft observation. Each piece is embedded in an epoxy cold embedding resin and allowed to harden. Next, the glass cloth embedded in the epoxy cold embedding resin is polished to a degree that allows observation of the warp or weft. An SEM (product name JSM-6390A, manufactured by JEOL Ltd.) is used to observe the average fiber diameter at a magnification of 2000x and the number of fibers at a magnification of 500x. (1) Average fiber diameter of glass yarn (μm) For both the warp and weft threads, 30 strands are randomly selected. The cross-section of the long fibers contained in each of these 30 glass threads is observed, and their diameter is measured. The average value of these measurements is then calculated to determine the average fiber diameter of the glass long fibers in the warp and weft threads. (2) Number of items (items) For both the warp and weft threads, 30 strands are randomly selected. The number of long fibers contained in each of the 30 glass threads is measured, and the average value is calculated to determine the number of warp and weft threads.

[0034] Furthermore, the count of the glass yarn in the glass cloth of the present invention is not particularly limited. For example, 0.5 to 25 tex is used, and from the viewpoint of making it easier to achieve the effects of the present invention, 0.5 to 12 tex is preferred, 0.5 to 5 tex is more preferred, and 0.8 to 3.2 tex is even more preferred. In the present invention, the count of the glass yarn is a value measured and calculated according to the method specified in "7.1 Count" of the Japanese Industrial Standard JIS R 3420 2013 "General Test Methods for Glass Fibers".

[0035] [Density and weave structure of glass cloth] The glass cloth of this invention has a warp and weft density of 70 threads / 25 mm or more. This increases the shear stress G in the weft direction of the glass cloth, resulting in a residual shear strain ratio of 2HG / G of 1.4 (deg -1 ) can be easily satisfied. From a similar viewpoint, the warp density and weft density are preferably 85 threads / 25mm or higher. There are no particular upper limits on the warp density and weft density, but from the viewpoint of further reducing the mass of the glass cloth, 130 threads / 25mm or lower is preferred, and 120 threads / 25mm or lower is more preferred. Specifically, warp density and weft density can be 70 to 130 threads / 25mm, preferably 85 to 120 threads / 25mm. In this invention, the warp density and weft density are values ​​measured and calculated according to the method specified in "7.9 Density (weaving density)" of the Japanese Industrial Standard JIS R 3420 2013 "General Test Methods for Glass Fibers".

[0036] Furthermore, when glass cloth is manufactured, the warp threads are subjected to more tension than the weft threads. Consequently, since the weft threads of glass cloth are manufactured under relatively less tension, the unevenness in thread width when viewed from the plane of the glass cloth is greater than that of the warp threads. Therefore, in this invention, the weft thread can also be defined as the glass thread among the warp and weft threads that has greater unevenness in thread width when viewed from the plane.

[0037] There are no particular restrictions on the weave structure of glass cloth, but examples include plain weave, satin weave, twill weave, diagonal weave, and rib weave. Among these, plain weave is preferred.

[0038] [Surface treatment of glass cloth] The glass cloth of the present invention contains (A) polyoxyalkylene bisphenol A ether and (B) a silane coupling agent having an acrylic group or a methacrylic group on at least a portion of the surface of the glass filaments. By including these, the bending hysteresis 2HB in the weft direction of the glass cloth is reduced, and the residual curvature 2HB / B is reduced to 0.5 cm. -1 ) or less. Furthermore, by including these, the shear hysteresis 2HG in the weft direction of the glass cloth is reduced, and the residual shear strain rate 2HG / G is 1.4 (deg -1 ) The following is possible:

[0039] Polyoxyalkylene bisphenol A ether is a compound represented by the following general formula (1). [ka]

[0040] In general formula (1), R 1 and R 2 n represents an alkylene group, either identical or different. The number of carbon atoms in the alkylene group can be, for example, 2 to 4, preferably 2 or 3, and more preferably 2. In general formula (1), n 1 and n 2 n represents the average number of moles of alkylene oxide added. 1 and n2 For example, 2 to 50, preferably 4 to 30, and more preferably 6 to 20. 1 and n 2 These may be different values, but may also be approximately the same value. As one embodiment of polyoxyalkylene bisphenol A ether, in general formula (1), R 1 and R 2 These are the same alkylene group, and n 1 and n 2 Examples include those with nearly identical numerical values.

[0041] The polyoxyalkylene bisphenol A ether used in the present invention is preferably polyoxyethylene bisphenol A ether or polyoxypropylene bisphenol A ether. Among these, polyoxyethylene bisphenol A ether is more preferred from the viewpoint of having excellent lubricity and making it easier to reduce the generation of lint in the glass cloth. The average number of moles of alkylene oxide added in the polyoxyalkylene bisphenol A ether used in the present invention is, for example, 2 to 40, preferably 4 to 30, and more preferably 6 to 20. Here, the average number of moles of alkylene oxide added in the polyoxyalkylene bisphenol A ether is the average value of the total number of alkylene oxides contained in the two polyalkylene oxide chains that constitute the polyoxyalkylene bisphenol A ether.

[0042] Examples of silane coupling agents having an acrylic group or a methacrylic group include compounds represented by the following general formula (2). [ka]

[0043] In general formula (2), R 3 R represents a hydrogen atom or a methyl group. In general formula (2), R 4 R is an alkylene group having 1 to 6 carbon atoms. 4Preferably, alkylene groups having 1 to 4 carbon atoms are used, more preferably alkylene groups having 2 to 4 carbon atoms, and even more preferably alkylene groups having 3 carbon atoms. 4 The alkylene group may be linear or branched, but is preferably branched. In general formula (2), R 5 and R 6 Each of these independently represents an alkyl group having 1 to 5 carbon atoms. 5 and R 6 Preferably, the group is an alkyl group having 1 to 3 carbon atoms, more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably a methyl group. In general formula (2), m represents an integer between 0 and 2. Preferably, m is 0 or 1, more preferably 0.

[0044] Specifically, as a silane coupling agent having an acrylic group or a methacrylic group, 3-acryloxypropyltrimethoxysilane (in general formula (2), R 3 H, R 4 ga is -C3H6-, m is 0, R 6 Compounds in which R is -CH3), 3-methacryloxypropyltrimethoxysilane (in general formula (2), 3 -CH3, R 4 ga is -C3H6-, m is 0, R 6 Compounds in which R is -CH3), 3-acryloxypropylmethyldimethoxysilane (in general formula (2), R 3 H, R 4 ga is -C3H6-, m is 1, R 5 and R 6 Compounds in which R is -CH3), 3-methacryloxypropylmethyldimethoxysilane (in general formula (2), R 3 -CH3, R 4 ga is -C3H6-, m is 1, R 5 and R 6 Compounds in which R is -CH3), 3-acryloxypropyltriethoxysilane (in general formula (2), 3 H, R 4 ga is -C3H6-, m is 0, R 6Compounds in which R is -C2H5), 3-methacryloxypropyltriethoxysilane (in general formula (2), R 3 -CH3, R 4 ga is -C3H6-, m is 0, R 6 Examples include compounds in which the parentheses are C2H5. Among these, 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane are preferred.

[0045] In the glass cloth of the present invention, the ratio of (A) polyoxyalkylene bisphenol A ether to (B) silane coupling agent having an acrylic group or a methacrylic group is, for example, 1 to 1000 parts by mass, preferably 10 to 500 parts by mass, and more preferably 50 to 400 parts by mass of (B) silane coupling agent having an acrylic group or a methacrylic group, per 100 parts by mass of the total amount of (A) polyoxyalkylene bisphenol A ether.

[0046] Furthermore, in the glass cloth of the present invention, the mass ratio of (A) polyoxyalkylene bisphenol A ether per 100 parts by mass of the total amount of components attached to the surface of the glass fibers is, for example, 10 to 90 parts by mass, preferably 10 to 80 parts by mass, more preferably 10 to 50 parts by mass, and even more preferably 15 to 45 parts by mass.

[0047] Furthermore, in the glass cloth of the present invention, the mass ratio of (B) silane coupling agent having an acrylic group or a methacrylic group per 100 parts by mass of the total amount of components attached to the surface of the glass long fibers is, for example, 10 to 90 parts by mass, preferably 20 to 80 parts by mass.

[0048] In the glass cloth of the present invention, at least a portion of the surface of the glass fibers may contain a silane coupling agent other than a silane coupling agent having an acrylic group or a methacrylic group (B). Examples of silane coupling agents other than a silane coupling agent having an acrylic group or a methacrylic group include a silane coupling agent having an amino group, a silane coupling agent having a vinyl group, a silane coupling agent having a phenyl group, a silane coupling agent having a glycidoxy group, a silane coupling agent having an isocyanate group, a silane coupling agent having a mercapto group, a silane coupling agent having a styryl group, a silane coupling agent having a ureido group, and the like. In particular, the combined use of a silane coupling agent having an acrylic group or a methacrylic group and a silane coupling agent having an amino group or a vinyl group is preferred in that it tends to improve adhesion with the matrix resin when forming a prepreg.

[0049] Examples of silane coupling agents having an organic functional group containing an amino group include the compound represented by the following general formula (3) and its salts. [ka]

[0050] In general formula (3), X represents an organic functional group having one or more amino groups. In general formula (3), p represents an integer between 0 and 2. Preferably, p is 0 or 1, more preferably 0. In general formula (3), R 7 and R 8 Each of these independently represents an alkyl group having 1 to 5 carbon atoms. 7 and R 8 Preferably, alkyl groups having 1 to 3 carbon atoms are used, and more preferably alkyl groups having 1 or 2 carbon atoms.

[0051] Examples of silane coupling agents having an amino group include individual compounds such as N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltriethoxysilane and its hydrochloride, N-β-(N-benzylaminoethyl)-γ-aminopropyltrimethoxysilane and its hydrochloride, N-β-(N-benzylaminoethyl)-γ-aminopropyltriethoxysilane and its hydrochloride, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, or mixtures thereof. Of these, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltriethoxysilane and its hydrochloride, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltriethoxysilane and its hydrochloride, N-β-(N-benzylaminoethyl)-γ-aminopropyltriethoxysilane and its hydrochloride, and N-β-(N-benzylaminoethyl)-γ-aminopropyltriethoxysilane and its hydrochloride are more preferred.

[0052] Examples of silane coupling agents having a vinyl group or a styryl group include compounds represented by the following general formula (4). [ka]

[0053] In general formula (4), Y represents an organic functional group containing one or more vinyl or styryl groups. In general formula (4), R 9 is an alkyl group having 1 to 8 carbon atoms, preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, or a t-butyl group. Also, in general formula (4), OR 10 is an alkoxy group having 1 to 8 carbon atoms, which may have substituents, and is preferably a methoxy group, an ethoxy group, or a methoxyethoxy group. In general formula (4), q is an integer from 0 to 2, and is preferably 0.

[0054] Specific examples of silane coupling agents having a vinyl group or a styryl group include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, and styryltrimethoxysilane.

[0055] In the glass cloth of the present invention, the mass ratio of the total amount of silane coupling agent per 100 parts by mass of the total amount of components attached to the surface of the glass fibers is, for example, 10 to 90 parts by mass, preferably 40 to 90 parts by mass, and more preferably 45 to 85 parts by mass. Here, the total amount of silane coupling agent is the sum of the mass of (B) the silane coupling agent having an acrylic group or a methacrylic group and any other silane coupling agents included as needed.

[0056] Furthermore, in the glass cloth of the present invention, the mass ratio of the silane coupling agent having (B) an acrylic group or a methacrylic group per 100 parts by mass of the total amount of silane coupling agent attached to the surface of the glass long fibers is, for example, 10 to 100 parts by mass, preferably 30 to 100 parts by mass, and more preferably 50 to 100 parts by mass. Here, the total amount of silane coupling agent is the sum of the mass of the silane coupling agent having (B) an acrylic group or a methacrylic group and any other silane coupling agents included as needed.

[0057] Furthermore, in the glass cloth of the present invention, at least a portion of the surface of the glass fibers may contain a softener, an antistatic agent, or a surfactant, as needed. The softener, antistatic agent, or surfactant may be appropriately selected depending on the type of surface treatment agent used.

[0058] [Physical properties of glass cloth, etc.] The glass cloth of the present invention has a carbon content of 0.4 to 1.5% by mass. This carbon content serves as an indicator of the amount of surface treatment agent adhering to it, which includes (A) polyoxyalkylene bisphenol A ether and (B) a silane coupling agent having an acrylic group or a methacrylic group. By setting the carbon content within the above range, the bending stiffness B can be effectively increased, and the residual curvature 2HB / B is 0.5 cm. -1 ) can be reduced to less than or equal to the above. From the viewpoint of improving adhesion with the matrix resin when forming a prepreg, the carbon content is more preferably 0.5 to 1.2 mass%, and even more preferably 0.6 to 1.1 mass%. In the present invention, the carbon content is a value measured by the following procedure. First, using a total carbon analyzer, the glass cloth is combusted and reduced under oxygen circulation at a reaction temperature of 850°C and a reduction temperature of 600°C, and the total organic carbon separated by chromatography using a porous polymer bead-packed column is quantified using a thermal conductivity detector (TCD). Next, the carbon content of the glass cloth is calculated from a calibration curve prepared using the elemental quantification standard sample acetanilide as a standard sample.

[0059] In the glass cloth of the present invention, the ignition loss is not particularly limited, but for example, it can be 0.2 to 1.5 mass%, preferably 0.5 to 1.5 mass%, more preferably 1.0 to 1.4 mass%, and even more preferably 1.05 to 1.3 mass%. In the present invention, the ignition loss is a value measured in accordance with the method specified in "7.3.2 Ignition Loss" of the Japanese Industrial Standard JIS R 3420:2013 "General Test Methods for Glass Fibers".

[0060] The mass of the glass cloth of the present invention is not particularly limited, but for example, 5 to 50 g / m² 2 These include 5-30g / m 2 Preferably, 5-20 g / m 2 This is more preferable. In the present invention, the mass of the glass cloth is a value measured in accordance with the method specified in "7.2 Mass of cloth and mat (mass)" of the Japanese Industrial Standard JIS R 3420:2013 "General Test Methods for Glass Fibers".

[0061] The thickness (μm) of the glass cloth in the present invention is not particularly limited, but for example, it can be 5 to 50 μm, preferably 5 to 30 μm, and more preferably 9 to 25 μm. In the present invention, the thickness of the glass cloth is a value measured using an electronic micrometer with a minimum display value of 0.001 mm, in accordance with Method B specified in "7.10.1 Thickness of Cloth" of the Japanese Industrial Standard JIS R3420:2013 "General Test Methods for Glass Fibers".

[0062] In the glass cloth of the present invention, the tensile strength in the warp direction can be 20 to 120 N / 25 mm, preferably 25 to 110 N / 25 mm, and more preferably 30 to 100 N / 25 mm. The above tensile strength is determined by using a constant-speed elongation tensile testing machine in accordance with the method specified in "7.4.2 For cloth" of the Japanese Industrial Standard JIS R 3420:2013 "General Test Methods for Glass Fibers," with a test specimen length of 25 cm, a test specimen width (width before unraveling the threads from both ends) of 30 mm, a gripping distance of 15 cm, a test specimen width (width after unraveling the threads from both ends) of 25 mm, and a constant-speed tensile speed of 200 mm / min. The tensile strength is measured five times in each direction of the warp of the glass cloth, and the average value is taken as the tensile strength in the warp direction of the glass cloth (N / 25 mm).

[0063] Furthermore, in the manufacture of glass cloth, the sizing agent and sizing agent required during the weaving of the warp and weft threads are de-oiled. This de-oiling process is called heat cleaning. The tensile strength of glass cloth that has undergone this heat cleaning process is reduced to about half or less compared to glass cloth before the heat cleaning process. The aforementioned preferred range of tensile strength of 20 to 120 N / 25 mm represents the tensile strength of heat-cleaned glass cloth, which is significantly different from that of glass cloth that has not undergone heat cleaning.

[0064] The glass cloth of the present invention is a glass cloth composed of glass yarn made of multiple glass filaments as warp and weft threads, wherein at least a portion of the surface of the glass filaments contains (A) polyoxyalkylene bisphenol A ether and (B) a silane coupling agent having an acrylic group or a methacrylic group, the weaving density of the glass cloth is 70 threads / 25 mm or more, and the carbon content of the glass cloth is 0.4 to 1.5% by mass, and based on this, the residual curvature 2HB / B is 0.5 cm -1 The following applies, and the residual shear strain rate 2HG / G is 1.4 (deg -1 The following can be satisfied. A more preferred range for the residual curvature 2HB / B of the glass cloth of the present invention is 0.1 cm -1 More than 0.5cm -1 The following are examples, including 0.2cm -1 Above 0.45cm -1 The following is more preferable. Furthermore, a more preferable range for the residual shear strain rate 2HG / G possessed by the glass cloth of the present invention is 0.1deg -1 The above is 1.4deg -1 The following is preferable: 0.5deg -1 The above is 1.2deg -1 The following is more preferable: 0.7deg -1 The above is 1.1 degrees. -1 The following is even more preferable.

[0065] In this invention, the residual curvature 2HB / B of the glass cloth is a value measured using a KES-FB2 pure bending tester manufactured by Kato Tech Co., Ltd. The method for measuring the residual curvature 2HB / B of the glass cloth will be described below with reference to Figure 1. The left figure of Figure 1(a) is a schematic diagram of the glass cloth bent into an arc shape using a pure bending tester, and the right figure of Figure 1(a) is a schematic diagram showing the bending moment (M) generated when the glass cloth is bent into an arc shape using a pure bending tester. Figure 1(b) is an example of a bending hysteresis curve obtained using a pure bending tester. First, two pieces of glass cloth cut to 20cm x 20cm are prepared, and these two pieces are stacked so that the warp and weft threads of each are in the same direction to make a test sample. If the warp and weft threads in the glass cloth cannot be immediately distinguished, as mentioned above, the thread with greater variation in thread width when viewed from the planar direction should be considered to be the weft thread. The test sample is fixed so that the distance between the chucks is 1 cm. When fixing, the weft of the test sample is wrapped evenly around the chucks from both ends in the longitudinal direction (i.e., the direction in which the weft is continuous). Then, as shown in Figure 1(a), the weft has a curvature K = +2.5 cm. -1 Maintaining constant velocity (deformation rate (0.5)) until it reaches this point. -1 The weft is then bent into an arc shape at a rate of / sec)) and then the weft reaches a maximum curvature of -2.5cm. -1 Maintaining constant velocity (deformation rate (0.5)) until it reaches this point. -1 A bending test is performed by bending the material in an arc shape to the opposite side at a rate of 1 / sec) and then returning it to its original shape, and the bending moment generated along with the change in curvature is measured (Figure 1(a)). The bending test is performed as one cycle, and a bending hysteresis curve (vertical axis: bending moment, horizontal axis: curvature) as shown in Figure 1(b) is obtained as the bending characteristic value. From this bending hysteresis curve, the bending stiffness B (gf·cm) per unit length can be calculated. 2 The bending stiffness B per unit length is calculated as curvature K = +0.5 cm. -1 +1.5cm -1 The mean slope of the differential value of the bending moment (M) measured between 2HB and the curvature K = +1.0 cm. -1This is calculated as the width of the hysteresis in the weft (see Figure 1(b)). This measurement can be performed using, for example, the KES-FB SYSTEM (Ver.7.18WJ) data measurement program, and B and 2HB can be calculated using the KES-FB CALC (Ver.7.07J) data calculation program. The above measurement is performed five times using 10 different glass cloth samples, and the average value of the residual shear strain rate 2HB / B, which is the ratio of the bending hysteresis 2HB in the weft direction to the bending stress B in the weft direction, is determined.

[0066] Furthermore, in this invention, the residual shear strain rate 2HG / G of the glass cloth is a value measured using a KES-FB1 tensile shear testing machine manufactured by Kato Tech Co., Ltd. The method for measuring the residual shear strain rate 2HG / G of the glass cloth will be described below with reference to Figure 2. Figure 2(a) is a schematic diagram of the state in which the glass cloth has been shear-deformed to a shear angle φ using a tensile shear testing machine, and Figure 2(b) is an example of a shear hysteresis curve obtained using a tensile shear testing machine. First, two pieces of glass cloth cut to 20cm x 20cm are prepared, and these two pieces are stacked so that the warp and weft threads of each are in the same direction to form a test sample. If the warp and weft threads in the glass cloth cannot be immediately distinguished, as mentioned above, the side with greater variation in thread width when viewed from the planar direction should be considered to be the weft thread. The test sample is fixed so that the distance between the chucks is 5cm. When fixing the test sample, the weft threads are wrapped evenly around the chuck from both ends in the longitudinal direction (i.e., the direction in which the weft threads are continuous) of the test sample. Next, as shown in Figure 2, a forced load (W) of 10gf / cm is applied in the longitudinal direction (i.e., the direction in which the weft threads are continuous) of the test sample, and the sample is deformed at a constant speed (0.00834° / sec) in the longitudinal direction (i.e., the direction in which the warp threads are continuous) until the shear angle φ = +8°. Then, it is deformed in the opposite direction until the shear angle φ = -8°, and then returned to its original position. The shear force generated along with the change in shear angle is measured (see Figure 2(a)). The shear test is performed as one cycle, and a shear hysteresis curve (vertical axis: shear force, horizontal axis: shear angle) as shown in Figure 2(b) is obtained as the shear characteristic value. From this shear hysteresis curve, the shear stress G (gf / cm / deg) in the weft direction and the hysteresis width 2HG (gf / cm) are determined. This measurement will be conducted under conditions of 23°C and 50% RH. The shear stress G per unit length will be calculated as the average slope of the derivative of the shear force (Fs) measured between shear angles φ = +0.5 and +2.5, and the hysteresis width 2HG will be calculated as the hysteresis width at shear angle φ = +0.5 (see Figure 2(b)).This measurement can be performed using, for example, the KES-FB SYSTEM (Ver.7.18WJ) data measurement program, and G and 2HG can be calculated using the KES-FB CALC (Ver.7.07J) data calculation program. The above measurement is performed five times using 10 different glass cloth samples, and the average value of the residual shear strain rate 2HG / G, which is the ratio of the shear hysteresis 2HG (gf / cm) in the weft direction to the shear stress G (gf / cm / deg) in the weft direction, is determined.

[0067] [Method for manufacturing glass cloth] Next, an example of a method for manufacturing glass cloth according to the present invention will be described. First, glass cloth is woven using glass yarn made of multiple glass filaments as warp and weft threads. Any conventionally known method can be used for weaving. For example, the warp threads may be subjected to a warping process and a sizing process, and then the weft threads may be beaten using a jet loom (e.g., an air jet loom, a water jet loom, etc.), a Sulzer loom, a Repier loom, etc.

[0068] Furthermore, if necessary, fiber opening treatment and / or heat cleaning treatment can be performed. Methods for fiber opening treatment include, for example, fiber opening treatment by pressure of a water flow on the obtained glass cloth, fiber opening treatment by high-frequency vibration using water (e.g., degassed water, ion-exchanged water, deionized water, electrolyzed cationized water, or electrolyzed anionized water, etc.) as a medium, and processing treatment by pressing with a roll. Such fiber opening treatment may be performed simultaneously with weaving or after weaving. In addition, fiber opening treatment may be performed before or after heat cleaning treatment or simultaneously with heat cleaning treatment, or simultaneously with or after the surface treatment described later. In addition, known methods can be used to adjust the degree of fiber opening of the warp and weft threads, and include methods of adjusting the warp tension, methods of adjusting and applying tension balance between the warp and weft directions while performing fiber opening using methods such as a pinch expander, curved rubber roller, rotating peripheral roller, Mirabou roller, or tenter in the weft direction, or methods of combining these.

[0069] If the woven glass cloth has substances (e.g., sizing agents) that hinder the adhesion and impregnation of the matrix resin when used as a prepreg or printed circuit board, it is preferable to remove these substances by, for example, heat cleaning. However, for glass cloth woven with glass yarn to which the primary and secondary adhesives have been treated with the surface treatment agents described later, the heat cleaning process can be omitted. The temperature conditions for the heat cleaning process are preferably 350°C or higher, more preferably 350 to 500°C, and even more preferably 380 to 450°C. The time for the heat cleaning process can be set appropriately according to the temperature conditions adopted, but for example, when the glass cloth is made into a roll product (a product in which glass cloth is wound onto a core) and the heat cleaning process is performed on the roll product, the time is 20 to 60 hours, preferably 24 to 48 hours, and even more preferably 24 to 36 hours.

[0070] Then, in the method for manufacturing glass cloth according to the present invention, the prepared glass cloth is subjected to surface treatment. For the surface treatment, first, a treatment agent is prepared.

[0071] The treatment agent to be prepared contains components to be attached to the surface of the glass long fibers and a solvent, and specifically, the treatment agent contains (A) polyoxyalkylene bisphenol A ether and / or (B) a silane coupling agent having an acrylic group or a methacrylic group, and a solvent. The type of solvent is not particularly limited, but water is an example.

[0072] The content of (A) polyoxyalkylene bisphenol A ether in the treatment agent is not particularly limited, but for example, it can be 1 to 30 g / L, preferably 2 to 20 g / L, and more preferably 3 to 15 g / L. The content of (B) silane coupling agent having an acrylic group or a methacrylic group in the treatment agent is not particularly limited, but for example, it can be 3 to 40 g / L, preferably 5 to 35 g / L, and more preferably 10 to 30 g / L.

[0073] The mass ratio of (A) polyoxyalkylene bisphenol A ether to the total mass of nonvolatile components contained in the treatment agent is not particularly limited, but for example, it is 10 to 90% by mass, preferably 20 to 80% by mass, more preferably 10 to 50% by mass, and even more preferably 15 to 45% by mass. The mass ratio of (B) silane coupling agent having an acrylic group or a methacrylic group to the total mass of nonvolatile components contained in the treatment agent is not particularly limited, but for example, it is 10 to 90% by mass, preferably 20 to 80% by mass. Furthermore, the mass ratio of the total silane coupling agent to the total mass of nonvolatile components contained in the treatment agent is not particularly limited, but for example, it is 10 to 90% by mass, preferably 40 to 90% by mass, and more preferably 45 to 85% by mass. Furthermore, the ratio of the total mass of silane coupling agents having an acrylic group or a methacrylic group to 100 parts by mass of the total silane coupling agents contained in the treatment agent is not particularly limited, but for example, it is 10 to 100 parts by mass, preferably 30 to 100 parts by mass, and more preferably 50 to 100 parts by mass. In this invention, "non-volatile component" refers to the oven-dried component when a constant weight is reached after heat treatment at 110°C under normal pressure to remove the solvent, etc., and is the component that ultimately adheres to and remains on the surface of the glass fibers in the glass cloth of this invention.

[0074] The glass cloth can be surface-treated by impregnating, coating, or spraying it with the prepared treatment agent, and then drying it. In the surface treatment process, the glass cloth may be surface-treated by applying a mixed treatment agent of (A) and (B) to the prepared glass cloth and drying it, or by applying (A) and (B) as separate treatment agents in two stages and drying them.

[0075] [Forms and uses of glass cloth] In one embodiment of the glass cloth of the present invention, it is provided as a roll-shaped long glass cloth wound around a core. When the glass cloth of the present invention is a roll-shaped long glass cloth, the length and width of the glass cloth are not particularly limited, but for example, the length can be 10 to 4000 m, preferably 50 to 3000 m, more preferably 100 to 2000 m, and the width can be 10 to 200 cm, preferably 30 to 150 cm, more preferably 50 to 130 cm.

[0076] The glass cloth of the present invention is suitably used as a fiber base material for prepregs. In particular, the glass cloth of the present invention is especially suitable as a fiber base material for prepregs for printed circuit boards. Prepregs using the glass cloth of the present invention will be described later.

[0077] 2. Prepreg The prepreg of the present invention comprises the aforementioned glass cloth and a thermosetting resin impregnated into the glass cloth.

[0078] The thermosetting resin is not particularly limited as long as it is a resin that hardens with heat, but examples include phenolic resins, epoxy resins, non-halogenated epoxy resins, cyanate resins, maleimide resins, bismaleimide resins, modified bismaleimide resins, isocyanate resins, benzocyclobutene resins, vinyl resins, bismaleimide triazine resins, phenolic resins, and thermosetting polyphenylene ether resins. The thermosetting resin may be used alone or in combination of two or more types.

[0079] Furthermore, the prepreg of the present invention may contain inorganic fillers. Examples of inorganic fillers include silicas such as natural silica, fused silica, amorphous silica, and hollow silica; boehmite; molybdenum compounds such as molybdenum oxide and zinc molybdate; and glass fillers such as alumina, talc, calcined talc, mica, glass short fibers, and spherical glass (glass fillers using E glass, T glass, UT glass, S glass, D glass, NE glass, L glass, LU glass, etc. as glass materials).

[0080] The prepreg of the present invention can be suitably used as a component material for printed circuit boards. [Examples]

[0081] The present invention will be described in detail below with reference to examples and comparative examples. However, the present invention is not limited to the examples.

[0082] 1. Measurement and Evaluation Methods 1-1. Average fiber diameter and number of glass fibers The average fiber diameter of the glass filaments and the number of glass filaments constituting the glass yarn were measured as follows. Specifically, two 30cm square pieces of the obtained glass cloth were prepared, one for warp observation and the other for weft observation, and each was embedded in epoxy cold embedding resin (product name Epoxy Resin Specific-40, manufactured by Storuas Co., Ltd.) and cured. Next, the glass cloth embedded in the epoxy cold embedding resin was polished to a degree in which the warp or weft could be observed, and the average fiber diameter was measured at a magnification of 2000x and the number of fibers at a magnification of 500x using a scanning electron microscope (SEM) (product name JSM-6390A, manufactured by JEOL Ltd.). (1) Average fiber diameter of glass long fibers (μm) For both the warp and weft threads, 30 strands were randomly selected. The cross-section of the long fibers contained in each of these 30 glass threads was observed, and their diameters were measured. The average value was then calculated to determine the average fiber diameter of the glass long fibers in the warp and weft threads. (2) Number of glass fibers (fibers) For both the warp and weft threads, 30 strands were randomly selected. The total number of long fibers contained in each of the 30 glass threads was measured, and the average value was calculated to determine the number of glass long fibers in the warp and weft threads.

[0083] 1-2. Weave density of glass cloth The weave density of the glass cloth was measured according to the method specified in "7.9 Density (weave density)" of the Japanese Industrial Standard JIS R 3420:2013 "General Test Methods for Glass Fibers". Specifically, the measurement target was a position at least 50 mm away from the edge and selvage of the glass cloth, with a measurement interval of 10 mm to 200 mm, and the total number of threads within the set measurement interval was measured. This was considered one measurement, and the number of threads within the measurement interval was measured again two more times using the same method, moving to a different position that did not contain the previously measured threads. After every three measurements, the number of threads per 25 mm was calculated according to the following formula, and the average of the three measured values ​​was calculated.

number

[0084] 1-3. Glass yarn count The yarn count of the glass fiber cloth was measured according to the method specified in "7.1 Yarn Count" of the Japanese Industrial Standard JIS R 3420 2013 "General Test Methods for Glass Fibers". Specifically, first, 500m of glass fiber was taken from the winding machine and used as a test specimen. The test specimen was placed flat and placed in a muffle furnace, fired at 625°C for 25 minutes, and then allowed to cool in a desiccator, after which the mass of the test specimen was measured. The yarn count was calculated according to the following formula.

number

[0085] 1-4. Mass of glass cloth The mass of the glass cloth was measured according to the method specified in "7.2 Mass of cloth and mat (mass)" of the Japanese Industrial Standard JIS R 3420:2013 "General Test Methods for Glass Fibers". Specifically, the mass was measured over an area of ​​100 cm² from a distance of 50 mm or more from the edge of the glass cloth. 2 A square test specimen was taken, dried at 105°C for 1 hour, and then its mass was measured. The following formula was used to determine the mass of the 1 m² specimen. 2 The mass per unit was calculated.

number

[0086] 1-5. Thickness of glass cloth The thickness of the glass cloth was measured according to Method B specified in "7.10.1 Thickness of Cloth" of the Japanese Industrial Standard JIS R3420:2013 "General Test Methods for Glass Fibers". Specifically, the thickness was measured at a point 50 mm or more inward from both ends and the selvage using an electronic micrometer with a minimum display value of 0.001 mm.

[0087] 1-6. Loss of weight on ignition of glass cloth The ignition loss of the glass cloth was measured according to the method specified in "7.3.2 Ignition Loss" of the Japanese Industrial Standard JIS R 3420:2013 "General Test Methods for Glass Fibers". Specifically, the measurement was taken from a point at least 10 mm inward from a corner or edge, at a distance of 100 cm. 2 The above test specimens were cut out and dried in a 105°C dryer for 30 minutes. After drying, the test specimens were transferred to a desiccator and allowed to cool to room temperature, and their mass was measured. Drying, cooling, and measurement were repeated until the mass became constant, and the mass of the dried test specimens was determined. Next, the dried test specimens were placed in a muffle furnace adjusted to 625°C and heated for 10 minutes or more. After removing the test specimens from the muffle furnace, they were transferred to a desiccator and allowed to cool, and their mass was measured. Heating, cooling, and measurement were repeated until the mass became constant, and the mass of the dried and heated test specimens was determined. The ignition loss (%) was calculated according to the following formula.

number

[0088] 1-7. Tensile strength of glass cloth The tensile strength of the glass cloth was determined according to the method specified in "7.4.2 For cloth" of the Japanese Industrial Standard JIS R 3420:2013 "General Test Methods for Glass Fibers," using a constant-speed elongation tensile testing machine (manufactured by Intesco Co., Ltd.). The test specimen length was 25 cm, the width of the specimen (before unraveling the threads from both ends) was 30 mm, the gripping distance was 15 cm, the width of the specimen (after unraveling the threads from both ends) was 25 mm, and the constant-speed tensile speed was 200 mm / min. The breaking strength was measured five times in the warp direction of the glass cloth, and the average of the measured values ​​was taken as the tensile strength of the glass cloth (N / 25 mm).

[0089] 1-8. Carbon content of glass cloth Using a total carbon analyzer (SUMIGRAPH® NCH-22F, manufactured by Sumika Analysis Center), glass cloth was combusted and reduced under oxygen circulation at a reaction temperature of 850°C and a reduction temperature of 600°C. The total organic carbon separated chromatographically using a porous polymer bead-packed column was quantified using a thermal conductivity detector (TCD). The carbon content of the glass cloth was calculated from a calibration curve created using acetanilide, an elemental quantification standard, as a standard sample.

[0090] 1-9. Unevenness in the width of warp and weft threads To assess the unevenness of the yarn width, a 20cm x 20cm piece of glass cloth was cut and observed from a planar direction using an optical microscope. One glass thread was arbitrarily selected from the warp threads, and for each of the three threads, the yarn width was measured at a point 1cm from the end along the length of the glass thread. This measurement was repeated 18 times at 1cm intervals along the length of the glass thread, for a total of 19 measurement points. The coefficient of variation (CV) of the yarn width at these 19 points was then calculated. This measurement was performed for the three glass threads constituting the warp threads, and the average of the CV values ​​for the three warp threads was calculated. The CV value of the yarn width of the glass threads constituting the weft threads was also calculated using the same method. A larger CV value indicates greater unevenness in yarn width.

[0091] 1-10.Residual curvature 2HB / B The residual curvature 2HB / B was measured using a KES-FB2 pure bending tester manufactured by Kato Tech Co., Ltd. as a bending measurement testing machine. Specifically, two pieces of glass cloth cut into 20 cm × 20 cm were prepared, and the two pieces were overlapped so that their warp and weft threads were in the same direction to form a test sample. The test sample was fixed so that the distance between the chucks was 1 cm. When fixing, it was evenly wound around the chucks from both ends in the length direction of the weft thread of the test sample. Then, as shown in Fig. 1(a), it was bent in an arc shape at a constant speed (deformation speed (0.5 -1 / sec)) until the weft thread had a curvature K = +2.5 cm -1 . Next, it was bent in an arc shape to the opposite side at a constant speed (deformation speed (0.5 -1 / sec)) until the weft thread had a maximum curvature of -2.5 cm -1 and then returned to its original state to conduct a bending test, and the bending moment generated along with the change in curvature was measured (Fig. 1(a)). The bending test was regarded as one cycle, and a bending hysteresis curve as shown in Fig. 1(b) was obtained as a bending characteristic value, and the bending rigidity B (gf·cm 2 / cm) per unit length and the width 2HB (gf·cm / cm) of the hysteresis were determined. This measurement was carried out under the environment of 23°C and 50% RH. In the present invention, B is the average slope of the differential value of the bending moment (M) measured between a curvature K = +0.5 cm -1 and +1.5 cm -1 , and 2HB was calculated as the width of the hysteresis at a curvature K = +1.0 cm -1 (see Fig. 1(b)). In this test, the measurement was carried out using a KES-FB SYSTEM (Ver.7.18WJ) data measurement program, and B and 2HB were calculated using a KES-FB CALC (Ver.7.07J) data calculation program. The above measurement was carried out 5 times using 10 different glass cloth samples, and the average value of the residual shear strain rate 2HB / B was determined.

[0092] 1-11. Residual shear strain rate 2HG / G The residual shear strain rate of 2HG / G was measured using a KES-FB1 tensile shear testing machine manufactured by Kato Tech Co., Ltd. Specifically, two pieces of glass cloth cut to 20cm x 20cm were prepared, and these two pieces were stacked so that the warp and weft threads of each were in the same direction to form the test sample. The test sample was fixed so that the distance between the chucks was 5cm. When fixing, the weft threads of the test sample were wrapped evenly around the chucks from both ends in the longitudinal direction. Next, as shown in Figure 2, a forced load (W) of 10gf / cm was applied in the longitudinal direction of the weft threads (i.e., the direction in which the weft threads are continuous), and the sample was deformed at a constant speed (0.00834° / sec) in the longitudinal direction of the warp threads (i.e., the direction in which the warp threads are continuous) until the shear angle φ = +8°. Then it was deformed in the opposite direction until the shear angle φ = -8°, and then returned to its original position. The shear force generated with the change in shear angle was measured (see Figure 2(a)). The shear test was performed in one cycle, and a shear hysteresis curve as shown in Figure 2(b) was obtained as the shear characteristic value. The shear stress G (gf / cm / deg) in the weft direction and the hysteresis width 2HG (gf / cm) were determined. This measurement was performed in an environment of 23°C and 50% RH. G was calculated as the average slope of the derivative of the shear force (Fs) measured between shear angles φ = +0.5 and +2.5, and 2HG was calculated as the hysteresis width at shear angle φ = +0.5 (see Figure 2(b)). In this measurement, the KES-FB SYSTEM (Ver.7.18WJ) data measurement program was used, and G and 2HG were calculated using the KES-FB CALC (Ver.7.07J) data calculation program. The above measurement was performed five times using 10 different glass cloth samples, and the average value of the residual shear strain rate 2HG / G was determined.

[0093] 1-12. Evaluation of the level of streaking in glass cloth The obtained glass cloth was randomly inspected in lengths of 1000m to observe the number of vertical streaks, and the number of vertical streaks per 100m was calculated and evaluated according to the following criteria. Note that only vertical streaks 100cm or longer were counted. A: The number of streaks was 0.0 per 100m. B: The number of streaks was 0.1 to 0.5 per 100m. C: The number of streaks was greater than 0.6 per 100m.

[0094] 1-13. Evaluation of whether or not diagonal wrinkles occur in the glass cloth. The obtained glass cloth was randomly inspected in lengths of 1000m, and the number of diagonal wrinkles was observed to evaluate the presence or absence of diagonal wrinkles. Diagonal wrinkles with a length of 10cm or more were counted. A: No diagonal wrinkles were observed. B: A number of diagonal wrinkles were observed.

[0095] 2. Manufacturing of glass cloth Example 1 Glass yarn was used as the warp and weft threads, consisting of glass filaments made from a low dielectric constant, low dielectric loss tangent glass material with a composition of SiO2: 51% by mass, Al2O3: 13% by mass, CaO: 8% by mass, B2O3: 23% by mass, and the remainder 5% by mass. The average fiber diameter was 4.0 μm and the number of fibers was 100. The glass yarn was woven on an air-jet loom to obtain a plain weave glass cloth roll (a roll of long glass cloth wound around a core) with a warp density of 75 threads / 25 mm and a weft density of 76 threads / 25 mm. The obtained glass cloth roll was then subjected to a heat cleaning treatment by heating at an ambient temperature of 400°C for 30 hours. No warp streaks or diagonal wrinkles were observed in the glass cloth after the heat cleaning treatment.

[0096] Next, a treatment agent of Formulation 1 was prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 1. (Prescription 1) N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride (manufactured by JNC Corporation, product name: Sylace® S-350, non-volatile component 30%): 9.0g / L 3-Methacryloxypropyltrimethoxysilane (manufactured by JNC Corporation, product name: Sylace® S-710, 98% non-volatile components): 13.5 g / L Polyoxyethylene bisphenol A ether (trade name GF690 manufactured by Yoshimura Oil Chemical Co., Ltd., non-volatile component 70%): 5.2 g / L The balance: pure water

[0097] The glass cloth subjected to heat cleaning treatment was impregnated with the treating agent of Formulation 1 while applying a tension of 150 N / m in the longitudinal direction of the warp (the direction in which the warp is continuous), and squeezed with nip rolls having a nip pressure of 35 N / cm 2 and dried at a temperature of 120°C. Next, after subjecting it to fibrillation treatment by high-pressure spraying, it was impregnated again with the treating agent of Formulation 1 and squeezed with nip rolls having a nip pressure of 35 N / cm 2 and dried at a temperature of 120°C to obtain a glass cloth.

[0098] In the obtained glass cloth, the weft has a greater unevenness in yarn width than the warp, the tensile strength in the warp direction is 96 N / 25 mm, the residual curvature 2HB / B in the weft direction is 0.41 (cm -1 ), the residual shear strain rate 2HG / G in the weft direction is 0.99 (deg -1 ), the loss on ignition is 1.16% by mass, and the carbon content is 0.72% by mass.

[0099] [Example 2] As the warp and weft, glass yarns composed of a low dielectric constant and low dielectric tangent glass material having a composition of SiO2: 51% by mass, Al2O3: 13% by mass, CaO: 8% by mass, B2O3: 23% by mass, and the balance 5% by mass, an average fiber diameter of 4.0 μm, and 100 fibers were used. The glass yarns were woven on an air jet loom to obtain a plain woven glass cloth roll having a warp density of 75 yarns / 25 mm and a weft density of 76 yarns / 25 mm. Next, the obtained glass cloth roll was subjected to heat cleaning treatment by heating at an atmospheric temperature of 400°C for 30 hours. No warp streaks or diagonal wrinkles occurred in the glass cloth after the heat cleaning treatment.

[0100] Next, a treating agent of Formulation 2 was prepared as a surface treating agent. The composition ratio of the non-volatile components of the treating agent is shown in Table 1. (Formulation 2) 3-Methacryloxypropyltrimethoxysilane (manufactured by JNC Corporation, product name Sylace® S710, 98% non-volatile components): 6.75 g / L Vinyltrimethoxysilane (manufactured by JNC Corporation, product name Sylace® S210, 99% non-volatile components): 6.0 g / L Polyoxyethylene bisphenol A ether (product name GF690, manufactured by Yoshimura Oil Chemical Co., Ltd., 70% non-volatile components): 15.7 g / L Polyalkylene polyamine fatty acid amide (product name KSK-2240, manufactured by Lion Specialty Chemicals Co., Ltd., 30% non-volatile components): 5.0 g / L Remainder: pure water

[0101] The heat-cleaned glass cloth is impregnated with the treatment agent of Formulation 2 while applying a tension of 150 N / m in the length direction of the warp threads, at 35 N / cm 2 The material was squeezed with a nip roll at a nip pressure of 35 N / cm² and dried at 120°C. Next, it underwent a fiber-opening treatment with a high-pressure spray, and then re-impregnated with the treatment agent of Formulation 2 at 35 N / cm². 2 Glass cloth was obtained by squeezing it with a nip roll at a nip pressure and drying it at a temperature of 120°C.

[0102] The resulting glass cloth had greater variation in yarn width in the weft threads than in the warp threads, a tensile strength in the warp direction of 81 N / 25 mm, and a residual curvature in the weft direction of 2 HB / B of 0.36 cm. -1 ), the residual shear strain rate in the weft direction is 2HG / G, which is 0.94 (deg -1 The ignition loss was 1.25% by mass, and the carbon content was 0.96% by mass.

[0103] [Example 3] Glass yarn was used as the warp and weft threads, consisting of glass filaments made from a low dielectric constant, low dielectric loss tangent glass material with a composition of SiO2: 51% by mass, Al2O3: 13% by mass, CaO: 8% by mass, B2O3: 23% by mass, and the remainder 5% by mass. The average fiber diameter was 4.0 μm and the number of fibers was 100. The glass yarn was woven on an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 75 threads / 25 mm and a weft density of 76 threads / 25 mm. The obtained glass cloth roll was then subjected to a heat cleaning treatment by heating it at an ambient temperature of 400°C for 30 hours. No warp streaks or diagonal wrinkles were observed in the glass cloth after the heat cleaning treatment.

[0104] Next, we prepared the treatment agent for Formulation 3 as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 1. (Prescription 3) 3-Methacryloxypropyltrimethoxysilane (manufactured by JNC Corporation, product name: Sylace® S-710, 98% non-volatile components): 13.5 g / L Polyoxyethylene bisphenol A ether (product name GF690, manufactured by Yoshimura Oil Chemical Co., Ltd., 70% non-volatile components): 5.2 g / L Remainder: pure water

[0105] The heat-cleaned glass cloth is impregnated with the treatment agent of Formulation 3 while applying a tension of 150 N / m in the length direction of the warp threads, at 35 N / cm 2 The material was squeezed with a nip roll at a nip pressure of 35 N / cm² and dried at 120°C. Next, it underwent a fiber-opening treatment with a high-pressure spray, and then re-impregnated with the treatment agent of Formulation 3 at 35 N / cm². 2 Glass cloth was obtained by squeezing it with a nip roll at a nip pressure and drying it at a temperature of 120°C.

[0106] The resulting glass cloth had greater variation in yarn width in the weft threads than in the warp threads, a tensile strength in the warp direction of 84 N / 25 mm, and a residual curvature in the weft direction of 2 HB / B of 0.34 cm. -1 ), the residual shear strain rate in the weft direction 2HG / G is 1.02 (deg -1The ignition loss was 1.10 mass%, and the carbon content was 0.65 mass%.

[0107] [Example 4] Glass yarn was used as the warp and weft threads, consisting of glass filaments made from a low dielectric constant, low dielectric loss tangent glass material with a composition of SiO2: 49% by mass, Al2O3: 14% by mass, CaO: 6% by mass, B2O3: 28% by mass, and the remainder 3% by mass. The average fiber diameter was 4.0 μm and the number of fibers was 50. The glass yarn was woven on an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 95 threads / 25 mm and a weft density of 95 threads / 25 mm. The obtained glass cloth roll was then subjected to a heat cleaning treatment by heating at an ambient temperature of 400°C for 30 hours. No warp streaks or diagonal wrinkles were observed in the glass cloth after the heat cleaning treatment.

[0108] Next, the treatment agent of Formulation 1 was prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 1.

[0109] The heat-cleaned glass cloth is impregnated with the treatment agent of Formulation 1 while applying a tension of 150 N / m in the length direction of the warp threads, at 35 N / cm 2 The material was squeezed with a nip roll at a nip pressure of 35 N / cm² and dried at 120°C. Next, it underwent a fiber-opening treatment with a high-pressure spray, and then re-impregnated with the treatment agent of Formulation 1 at 35 N / cm². 2 Glass cloth was obtained by squeezing it with a nip roll at a nip pressure and drying it at a temperature of 120°C.

[0110] The resulting glass cloth had greater variation in yarn width in the weft threads than in the warp threads, a tensile strength in the warp direction of 49 N / 25 mm, and a residual curvature in the weft direction of 2 HB / B of 0.40 cm. -1 ), the residual shear strain rate in the weft direction is 2HG / G, which is 0.96 (deg -1 The ignition loss was 1.13% by mass, and the carbon content was 0.64% by mass.

[0111] [Example 5] Glass yarn was used as the warp and weft threads, consisting of glass filaments made from a low dielectric constant, low dielectric loss tangent glass material with a composition of SiO2: 49% by mass, Al2O3: 14% by mass, CaO: 6% by mass, B2O3: 28% by mass, and the remainder 3% by mass. The average fiber diameter was 4.0 μm and the number of fibers was 50. The glass yarn was woven on an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 95 threads / 25 mm and a weft density of 95 threads / 25 mm. The obtained glass cloth roll was then subjected to a heat cleaning treatment by heating at an ambient temperature of 400°C for 30 hours. No warp streaks or diagonal wrinkles were observed in the glass cloth after the heat cleaning treatment.

[0112] Next, the treatment agent for Formulation 2 was prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 1.

[0113] The heat-cleaned glass cloth is impregnated with the treatment agent of Formulation 2 while applying a tension of 150 N / m in the length direction of the warp threads, at 35 N / cm 2 The fibers were squeezed using a nip roll with a nip pressure of 35 N / cm² and dried at 120°C. Next, they were subjected to a high-pressure spray treatment to open the fibers, and then re-impregnated with the treatment agent of Formulation 2 at 35 N / cm². 2 Glass cloth was obtained by squeezing it with a nip roll at a nip pressure and drying it at a temperature of 120°C.

[0114] The resulting glass cloth had greater variation in yarn width in the weft threads than in the warp threads, a tensile strength in the warp direction of 50 N / 25 mm, and a residual curvature in the weft direction of 2 HB / B of 0.43 cm. -1 ), the residual shear strain rate in the weft direction is 2HG / G, which is 0.93 (deg -1 The ignition loss was 1.35% by mass, and the carbon content was 1.06% by mass.

[0115] [Example 6] Glass yarn was used as the warp and weft threads, consisting of glass filaments made from a low dielectric constant, low dielectric loss tangent glass material with a composition of SiO2: 49% by mass, Al2O3: 14% by mass, CaO: 6% by mass, B2O3: 28% by mass, and the remainder 3% by mass. The average fiber diameter was 4.0 μm and the number of fibers was 50. The glass yarn was woven on an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 95 threads / 25 mm and a weft density of 95 threads / 25 mm. The obtained glass cloth roll was then subjected to a heat cleaning treatment by heating at an ambient temperature of 400°C for 30 hours. No warp streaks or diagonal wrinkles were observed in the glass cloth after the heat cleaning treatment.

[0116] Next, the treatment agent of formulation 3 was prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 2.

[0117] The heat-cleaned glass cloth is impregnated with the treatment agent of Formulation 3 while applying a tension of 150 N / m in the length direction of the warp threads, at 35 N / cm 2 The material was squeezed using a nip roll with a nip pressure of 35 N / cm² and dried at 120°C. Next, it underwent a fiber-opening treatment with a high-pressure spray, and then re-impregnated with the treatment agent of Formulation 3 at 35 N / cm². 2 Glass cloth was obtained by squeezing it with a nip roll at a nip pressure and drying it at a temperature of 120°C.

[0118] The resulting glass cloth had greater variation in yarn width in the weft threads than in the warp threads, a tensile strength in the warp direction of 52 N / 25 mm, and a residual curvature in the weft direction of 2 HB / B of 0.41 cm. -1 ), the residual shear strain rate in the weft direction is 2HG / G, which is 1.07 (deg -1 The ignition loss was 1.06 mass%, and the carbon content was 0.70 mass%.

[0119] [Example 7] As the warp and weft threads, glass yarn was used, consisting of glass long fibers with an average fiber diameter of 4.0 μm and a fiber count of 40, composed of a low dielectric constant, low dielectric loss tangent glass material with a composition of SiO2: 50% by mass, Al2O3: 15% by mass, CaO: 5% by mass, B2O3: 27% by mass, and the remainder being 3% by mass. The glass yarn was woven on an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 95 threads / 25 mm and a weft density of 95 threads / 25 mm. The obtained glass cloth roll was then subjected to a heat cleaning treatment by heating at an ambient temperature of 400°C for 30 hours. No warp streaks or diagonal wrinkles were observed in the glass cloth after the heat cleaning treatment.

[0120] Next, the treatment agent for Formulation 1 was prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 2.

[0121] The heat-cleaned glass cloth is impregnated with the treatment agent of Formulation 1 while applying a tension of 150 N / m in the length direction of the warp threads, at 35 N / cm 2 The material was squeezed with a nip roll at a nip pressure of 35 N / cm² and dried at 120°C. Next, it underwent a fiber-opening treatment with a high-pressure spray, and then re-impregnated with the treatment agent of Formulation 1 at 35 N / cm². 2 Glass cloth was obtained by squeezing it with a nip roll at a nip pressure and drying it at a temperature of 120°C.

[0122] The resulting glass cloth had greater variation in yarn width in the weft threads than in the warp threads, a tensile strength in the warp direction of 36 N / 25 mm, and a residual curvature in the weft direction of 2 HB / B of 0.44 cm. -1 ), the residual shear strain rate in the weft direction is 2HG / G, which is 0.89 (deg -1 The ignition loss was 1.17 mass%, and the carbon content was 0.80 mass%.

[0123] [Example 8] As the warp and weft threads, glass yarn was used, consisting of glass long fibers with an average fiber diameter of 4.0 μm and a fiber count of 40, composed of a low dielectric constant, low dielectric loss tangent glass material with a composition of SiO2: 50% by mass, Al2O3: 15% by mass, CaO: 5% by mass, B2O3: 27% by mass, and the remainder being 3% by mass. The glass yarn was woven on an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 95 threads / 25 mm and a weft density of 95 threads / 25 mm. The obtained glass cloth roll was then subjected to a heat cleaning treatment by heating at an ambient temperature of 400°C for 30 hours. No warp streaks or diagonal wrinkles were observed in the glass cloth after the heat cleaning treatment.

[0124] Next, the treatment agent for Formulation 2 was prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 2.

[0125] The heat-cleaned glass cloth is impregnated with the treatment agent of Formulation 2 while applying a tension of 150 N / m in the length direction of the warp threads, at 35 N / cm 2 The fibers were squeezed using a nip roll with a nip pressure of 35 N / cm² and dried at 120°C. Next, they were subjected to a high-pressure spray treatment to open the fibers, and then re-impregnated with the treatment agent of Formulation 2 at 35 N / cm². 2 Glass cloth was obtained by squeezing it with a nip roll at a nip pressure and drying it at a temperature of 120°C.

[0126] The resulting glass cloth had greater variation in yarn width in the weft threads than in the warp threads, a tensile strength in the warp direction of 36 N / 25 mm, and a residual curvature in the weft direction of 2 HB / B of 0.49 cm. -1 ), the residual shear strain rate in the weft direction is 2HG / G, which is 0.89 (deg -1 The ignition loss was 1.30% by mass, and the carbon content was 0.92% by mass.

[0127] [Example 9] As the warp and weft threads, glass yarn was used, consisting of glass long fibers with an average fiber diameter of 4.0 μm and a fiber count of 40, composed of a low dielectric constant, low dielectric loss tangent glass material with a composition of SiO2: 50% by mass, Al2O3: 15% by mass, CaO: 5% by mass, B2O3: 27% by mass, and the remainder being 3% by mass. The glass yarn was woven on an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 95 threads / 25 mm and a weft density of 95 threads / 25 mm. The obtained glass cloth roll was then subjected to a heat cleaning treatment by heating at an ambient temperature of 400°C for 30 hours. No warp streaks or diagonal wrinkles were observed in the glass cloth after the heat cleaning treatment.

[0128] Next, the treatment agent of Formulation 3 was prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 2.

[0129] The heat-cleaned glass cloth is impregnated with the treatment agent of Formulation 3 while applying a tension of 150 N / m in the length direction of the warp threads, at 35 N / cm 2 The material was squeezed using a nip roll with a nip pressure of 35 N / cm² and dried at 120°C. Next, it underwent a fiber-opening treatment with a high-pressure spray, and then re-impregnated with the treatment agent of Formulation 3 at 35 N / cm². 2 Glass cloth was obtained by squeezing it with a nip roll at a nip pressure and drying it at a temperature of 120°C.

[0130] The resulting glass cloth had greater variation in yarn width in the weft threads than in the warp threads, a tensile strength in the warp direction of 39 N / 25 mm, and a residual curvature in the weft direction of 2 HB / B of 0.49 cm. -1 ), the residual shear strain rate in the weft direction 2HG / G is 1.01 (deg -1 The ignition loss was 1.18 mass%, and the carbon content was 0.66 mass%.

[0131] [Example 10] Glass yarn was used as the warp and weft threads, consisting of glass filaments composed of E-glass with a composition of SiO2: 54% by mass, Al2O3: 14% by mass, CaO: 23% by mass, MgO: 1% by mass, B2O3: 6% by mass, and the remainder 2% by mass, with an average fiber diameter of 3.6 μm and 38 strands per filament. The glass yarn was woven on an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 105 threads / 25 mm and a weft density of 110 threads / 25 mm. The obtained glass cloth roll was then subjected to a heat cleaning treatment by heating at an ambient temperature of 400°C for 30 hours. No warp streaks or diagonal wrinkles were observed in the glass cloth after the heat cleaning treatment.

[0132] Next, the treatment agent for Formulation 1 was prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 2.

[0133] The heat-cleaned glass cloth is impregnated with the treatment agent of Formulation 1 while applying a tension of 150 N / m in the length direction of the warp threads, at 35 N / cm 2 The material was squeezed with a nip roll at a nip pressure of 35 N / cm² and dried at 120°C. Next, it underwent a fiber-opening treatment with a high-pressure spray, and then re-impregnated with the treatment agent of Formulation 1 at 35 N / cm². 2 Glass cloth was obtained by squeezing it with a nip roll at a nip pressure and drying it at a temperature of 120°C.

[0134] The resulting glass cloth had greater variation in yarn width in the weft threads than in the warp threads, a tensile strength in the warp direction of 51 N / 25 mm, and a residual curvature in the weft direction of 2 HB / B of 0.48 cm. -1 ), the residual shear strain rate in the weft direction is 2HG / G, which is 1.03 (deg -1 The ignition loss was 0.61% by mass, and the carbon content was 0.73% by mass.

[0135] [Comparative Example 1] Glass yarn was used as the warp and weft threads, consisting of glass filaments made from a low dielectric constant, low dielectric loss tangent glass material with a composition of SiO2: 51% by mass, Al2O3: 13% by mass, CaO: 8% by mass, B2O3: 23% by mass, and the remainder 5% by mass. The average fiber diameter was 4.0 μm and the number of fibers was 100. The glass yarn was woven on an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 75 threads / 25 mm and a weft density of 76 threads / 25 mm. The obtained glass cloth roll was then subjected to a heat cleaning treatment by heating it at an ambient temperature of 400°C for 30 hours. No warp streaks or diagonal wrinkles were observed in the glass cloth after the heat cleaning treatment.

[0136] Next, we prepared the treatment agent of Formulation 4 as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 3. (Prescription 4) N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride (manufactured by JNC Corporation, product name: Sylace® S-350, non-volatile component 30%): 9.0g / L Trimethoxyphenylsilane (product name Z6124, manufactured by DuPont-Toray Specialty Materials Co., Ltd., 90% non-volatile components): 14.7 g / L Remainder: pure water

[0137] The heat-cleaned glass cloth is impregnated with the treatment agent of Formulation 4 while applying a tension of 150 N / m in the length direction of the warp threads, at 35 N / cm 2 The material was squeezed with a nip roll at a nip pressure of 35 N / cm² and dried at 120°C. Next, it underwent a fiber-opening treatment with a high-pressure spray, and then re-impregnated with the treatment agent of Formulation 4 at 35 N / cm². 2 Glass cloth was obtained by squeezing it with a nip roll at a nip pressure and drying it at a temperature of 120°C.

[0138] The resulting glass cloth had greater variation in yarn width in the weft threads than in the warp threads, a tensile strength in the warp direction of 96 N / 25 mm, and a residual curvature in the weft direction of 2 HB / B of 0.34 cm. -1 ), the residual shear strain rate in the weft direction is 2.96 (deg -1The ignition loss was 0.99% by mass, and the carbon content was 0.43% by mass.

[0139] [Comparative Example 2] Glass yarn was used as the warp and weft threads, consisting of glass filaments made from a low dielectric constant, low dielectric loss tangent glass material with a composition of SiO2: 51% by mass, Al2O3: 13% by mass, CaO: 8% by mass, B2O3: 23% by mass, and the remainder 5% by mass. The average fiber diameter was 4.0 μm and the number of fibers was 100. The glass yarn was woven on an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 75 threads / 25 mm and a weft density of 76 threads / 25 mm. The obtained glass cloth roll was then subjected to a heat cleaning treatment by heating it at an ambient temperature of 400°C for 30 hours. No warp streaks or diagonal wrinkles were observed in the glass cloth after the heat cleaning treatment.

[0140] Next, we prepared the treatment agent of Formulation 5 as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 3. (Prescription 5) N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride (manufactured by JNC Corporation, product name: Sylace® S-350, non-volatile component 30%): 9.0g / L Remainder: pure water

[0141] The heat-cleaned glass cloth is impregnated with the treatment agent of Formulation 5 while applying a tension of 150 N / m in the length direction of the warp threads, at 35 N / cm 2 The material was squeezed with a nip roll at a nip pressure of 35 N / cm² and dried at 120°C. Next, it underwent a fiber-opening treatment with a high-pressure spray, and then re-impregnated with the treatment agent of Formulation 5 at 35 N / cm². 2 Glass cloth was obtained by squeezing it with a nip roll at a nip pressure and drying it at a temperature of 120°C.

[0142] The resulting glass cloth had greater variation in yarn width in the weft threads than in the warp threads, a tensile strength in the warp direction of 78 N / 25 mm, and a residual curvature in the weft direction of 2 HB / B of 0.62 cm. -1), the residual shear strain rate in the weft direction is 2HG / G, which is 1.83 (deg -1 The ignition loss was 0.63% by mass, and the carbon content was 0.14% by mass.

[0143] [Comparative Example 3] Glass yarn was used as the warp and weft threads, consisting of glass filaments made from a low dielectric constant, low dielectric loss tangent glass material with a composition of SiO2: 51% by mass, Al2O3: 13% by mass, CaO: 8% by mass, B2O3: 23% by mass, and the remainder 5% by mass. The average fiber diameter was 4.0 μm and the number of fibers was 100. The glass yarn was woven on an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 75 threads / 25 mm and a weft density of 76 threads / 25 mm. The obtained glass cloth roll was then subjected to a heat cleaning treatment by heating it at an ambient temperature of 400°C for 30 hours. No warp streaks or diagonal wrinkles were observed in the glass cloth after the heat cleaning treatment.

[0144] Next, a treatment agent of formulation 6 was prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 3. (Prescription 6) N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride (manufactured by JNC Corporation, product name: Sylace® S-350, non-volatile component 30%): 3.0g / L Polyoxyethylene bisphenol A ether (product name GF690, manufactured by Yoshimura Oil Chemical Co., Ltd., 70% non-volatile components): 5.2 g / L Remainder: pure water

[0145] The heat-cleaned glass cloth is impregnated with the treatment agent of Formulation 6 while applying a tension of 150 N / m in the length direction of the warp threads, at 35 N / cm 2 The material was squeezed using a nip roll with a nip pressure of 35 N / cm² and dried at 120°C. Next, it underwent a fiber-opening treatment with a high-pressure spray, and then re-impregnated with the treatment agent of Formulation 6 at 35 N / cm². 2 Glass cloth was obtained by squeezing it with a nip roll at a nip pressure and drying it at a temperature of 120°C.

[0146] The resulting glass cloth had greater variation in yarn width in the weft threads than in the warp threads, a tensile strength in the warp direction of 92 N / 25 mm, and a residual curvature in the weft direction of 2 HB / B of 1.42 cm. -1 ), the residual shear strain rate in the weft direction is 2HG / G, which is 1.09 (deg -1 The ignition loss was 0.85% by mass, and the carbon content was 0.24% by mass.

[0147] [Comparative Example 4] Glass yarn was used as the warp and weft threads, consisting of glass filaments made from a low dielectric constant, low dielectric loss tangent glass material with a composition of SiO2: 49% by mass, Al2O3: 14% by mass, CaO: 6% by mass, B2O3: 28% by mass, and the remainder 3% by mass. The average fiber diameter was 4.0 μm and the number of fibers was 50. The glass yarn was woven on an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 95 threads / 25 mm and a weft density of 95 threads / 25 mm. The obtained glass cloth roll was then subjected to a heat cleaning treatment by heating at an ambient temperature of 400°C for 30 hours. No warp streaks or diagonal wrinkles were observed in the glass cloth after the heat cleaning treatment.

[0148] Next, the treatment agent of formulation 5 was prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 3.

[0149] The heat-cleaned glass cloth is impregnated with the treatment agent of Formulation 5 while applying a tension of 150 N / m in the length direction of the warp threads, at 35 N / cm 2 The material was squeezed using a nip roll with a nip pressure of 35 N / cm² and dried at 120°C. Next, it underwent a fiber-opening treatment with a high-pressure spray, and then re-impregnated with the treatment agent of Formulation 5 at 35 N / cm². 2 Glass cloth was obtained by squeezing it with a nip roll at a nip pressure and drying it at a temperature of 120°C.

[0150] The resulting glass cloth had greater variation in yarn width in the weft threads than in the warp threads, a tensile strength in the warp direction of 53 N / 25 mm, and a residual curvature in the weft direction of 2 HB / B of 0.58 cm. -1), the residual shear strain rate in the weft direction is 2HG / G, which is 1.79 (deg -1 The ignition loss was 0.65 mass%, and the carbon content was 0.12 mass%.

[0151] [Comparative Example 5] As the warp and weft threads, glass yarn was used, consisting of glass long fibers with an average fiber diameter of 4.0 μm and a fiber count of 40, composed of a low dielectric constant, low dielectric loss tangent glass material with a composition of SiO2: 50% by mass, Al2O3: 15% by mass, CaO: 5% by mass, B2O3: 27% by mass, and the remainder being 3% by mass. The glass yarn was woven on an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 95 threads / 25 mm and a weft density of 95 threads / 25 mm. The obtained glass cloth roll was then subjected to a heat cleaning treatment by heating at an ambient temperature of 400°C for 30 hours. No warp streaks or diagonal wrinkles were observed in the glass cloth after the heat cleaning treatment.

[0152] Next, the treatment agent of formulation 5 was prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 3.

[0153] The heat-cleaned glass cloth is impregnated with the treatment agent of Formulation 5 while applying a tension of 150 N / m in the length direction of the warp threads, at 35 N / cm 2 The material was squeezed using a nip roll with a nip pressure of 35 N / cm² and dried at 120°C. Next, it underwent a fiber-opening treatment with a high-pressure spray, and then re-impregnated with the treatment agent of Formulation 5 at 35 N / cm². 2 Glass cloth was obtained by squeezing it with a nip roll at a nip pressure and drying it at a temperature of 120°C.

[0154] The resulting glass cloth had greater variation in yarn width in the weft threads than in the warp threads, a tensile strength in the warp direction of 30 N / 25 mm, and a residual curvature in the weft direction of 2 HB / B of 0.56 cm. -1 ), the residual shear strain rate in the weft direction is 2HG / G, which is 1.63 (deg -1 The ignition loss was 0.65 mass%, and the carbon content was 0.12 mass%.

[0155] [Comparative Example 6] Glass yarn was used as the warp and weft threads, consisting of glass filaments composed of E-glass with a composition of SiO2: 54% by mass, Al2O3: 14% by mass, CaO: 23% by mass, MgO: 1% by mass, B2O3: 6% by mass, and the remainder 2% by mass, with an average fiber diameter of 3.6 μm and 38 strands per filament. The glass yarn was woven on an air-jet loom to obtain a plain weave glass cloth roll with a warp density of 105 threads / 25 mm and a weft density of 110 threads / 25 mm. The obtained glass cloth roll was then subjected to a heat cleaning treatment by heating at an ambient temperature of 400°C for 30 hours. No warp streaks or diagonal wrinkles were observed in the glass cloth after the heat cleaning treatment.

[0156] Next, the treatment agent of formulation 5 was prepared as a surface treatment agent. The composition ratio of the non-volatile components of the treatment agent is shown in Table 3.

[0157] The heat-cleaned glass cloth is impregnated with the treatment agent of Formulation 5 while applying a tension of 150 N / m in the length direction of the warp threads, at 35 N / cm 2 The material was squeezed using a nip roll with a nip pressure of 35 N / cm² and dried at 120°C. Next, it underwent a fiber-opening treatment with a high-pressure spray, and then re-impregnated with the treatment agent of Formulation 5 at 35 N / cm². 2 Glass cloth was obtained by squeezing it with a nip roll at a nip pressure and drying it at a temperature of 120°C.

[0158] The resulting glass cloth had greater variation in yarn width in the weft threads than in the warp threads, a tensile strength in the warp direction of 43 N / 25 mm, and a residual curvature in the weft direction of 2 HB / B of 0.79 cm. -1 ), the residual shear strain rate in the weft direction is 2HG / G, which is 1.59 (deg -1 The ignition loss was 0.23% by mass, and the carbon content was 0.21% by mass.

[0159] 3.Results For each glass cloth, the average fiber diameter and number of glass fibers contained in the glass yarn used, weaving density, yarn count, mass, thickness, ignition loss, tensile strength and carbon content, residual curvature 2HB / B, residual shear strain 2HG / G, occurrence of warp streaks, and occurrence of diagonal wrinkles were evaluated. The evaluation results are shown in Tables 1, 2, and 3.

[0160] [Table 1]

[0161] [Table 2]

[0162] [Table 3]

[0163] The glass cloths of Examples 1 to 10 are glass cloths composed of glass yarns made of multiple glass filaments as warp and weft threads, wherein at least a portion of the surface of the glass filaments contains (A) polyoxyalkylene bisphenol A ether and (B) a silane coupling agent having an acrylic group or a methacrylic group, the weaving density of the glass cloth is 70 threads / 25 mm or more, and the carbon content of the glass cloth is 0.4 to 1.5 mass%, so the residual curvature 2HB / B is 0.5 (cm -1 ) or less, and the residual shear strain rate 2HG / G is 1.4 (deg -1 ) The following glass cloths could be obtained. Furthermore, the glass cloths of Examples 1 to 10 were able to suppress the occurrence of vertical and diagonal wrinkles.

[0164] On the other hand, although the glass cloth of Comparative Example 1 had a carbon content of 0.4% by mass or more, it did not contain (A) polyoxyalkylene bisphenol A ether and (B) a silane coupling agent having an acrylic group or a methacrylic group in at least a portion of the surface of the glass long fibers, so the residual shear strain rate 2HG / G was 1.4 (deg -1 This exceeded the previous result. Furthermore, the glass cloth in Comparative Example 1 was unable to suppress the occurrence of diagonal wrinkles.

[0165] Furthermore, the glass cloths of Comparative Examples 2, 4-6 had a carbon content of less than 0.4% by mass, and did not contain (A) polyoxyalkylene bisphenol A ether and (B) silane coupling agents having acrylic or methacrylic groups on at least a portion of the surface of the glass long fibers, resulting in a residual curvature of 2HB / B of 0.5 cm. -1 ) is greater than and the residual shear strain rate 2HG / G is 1.4 (deg -1 ) exceeded the limit. Furthermore, the glass cloths of Comparative Examples 2, 4-6 were unable to suppress the occurrence of vertical streaks and diagonal wrinkles.

[0166] The glass cloth of Comparative Example 3 had a carbon content of less than 0.4% by mass and did not contain a silane coupling agent having (B) acrylic groups or methacrylic groups on at least a portion of the surface of the glass long fibers, resulting in a residual shear strain of 1.4 (deg -1 It exceeded the limit. Furthermore, the glass cloth of Comparative Example 3 was unable to suppress the occurrence of vertical streaks.

Claims

1. A glass cloth composed of glass threads made from multiple glass filaments, with glass threads used as warp and weft threads, The glass long fibers contain (A) polyoxyalkylene bisphenol A ether and (B) a silane coupling agent having an acrylic group or a methacrylic group on at least a portion of the surface, The warp and weft density of the aforementioned glass cloth is 70 threads / 25 mm or more. A glass cloth having a carbon content of 0.4 to 1.5% by mass.

2. The glass cloth according to claim 1, wherein the tensile strength in the warp direction is 20 to 120 N / 25 mm.

3. The glass cloth according to claim 1 or 2, wherein the thickness is 5 to 30 μm.

4. The glass cloth according to any one of claims 1 to 3, which is a roll-shaped long glass cloth in which glass cloth is wound around a winding core.

5. A prepreg comprising a glass cloth according to any one of claims 1 to 4 and a thermosetting resin impregnated into the glass cloth.

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